From 461b008e5ff045cc9573ce04374ab8825a36f1a0 Mon Sep 17 00:00:00 2001
From: Dennis Snell <dennis.snell@automattic.com>
Date: Fri, 8 Nov 2019 22:40:54 -0600
Subject: [PATCH 01/34] JavaScript: Stop breaking surrogate pairs in toDelta()

Resolves #69 for JavaScript

Sometimes we can find a common prefix that runs into the middle of a
surrogate pair and we split that pair when building our diff groups.

This is fine as long as we are operating on UTF-16 code units. It
becomes problematic when we start trying to treat those substrings as
valid Unicode (or UTF-8) sequences.

When we pass these split groups into `toDelta()` we do just that and the
library crashes. In this patch we're post-processing the diff groups
before encoding them to make sure that we un-split the surrogate pairs.

The post-processed diffs should produce the same output when applying
the diffs. The diff string itself will be different but should change
that much - only by a single character at surrogate boundaries.
---
 javascript/diff_match_patch_uncompressed.js | 25 +++++++++
 javascript/tests/diff_match_patch_test.js   | 58 +++++++++++++++++++++
 2 files changed, 83 insertions(+)

diff --git a/javascript/diff_match_patch_uncompressed.js b/javascript/diff_match_patch_uncompressed.js
index 88a702c..e8bb278 100644
--- a/javascript/diff_match_patch_uncompressed.js
+++ b/javascript/diff_match_patch_uncompressed.js
@@ -1339,6 +1339,15 @@ diff_match_patch.prototype.diff_levenshtein = function(diffs) {
   return levenshtein;
 };
 
+diff_match_patch.prototype.isHighSurrogate = function(c) {
+  var v = c.charCodeAt(0);
+  return v >= 0xD800 && v <= 0xDBFF;
+}
+
+diff_match_patch.prototype.isLowSurrogate = function(c) {
+  var v = c.charCodeAt(0);
+  return v >= 0xDC00 && v <= 0xDFFF;
+}
 
 /**
  * Crush the diff into an encoded string which describes the operations
@@ -1350,7 +1359,23 @@ diff_match_patch.prototype.diff_levenshtein = function(diffs) {
  */
 diff_match_patch.prototype.diff_toDelta = function(diffs) {
   var text = [];
+  var lastEnd;
   for (var x = 0; x < diffs.length; x++) {
+
+    var thisDiff = diffs[x];
+    var thisTop = thisDiff[1][0];
+    var thisEnd = thisDiff[1][thisDiff[1].length - 1];
+
+    if (thisEnd && this.isHighSurrogate(thisEnd)) {
+      thisDiff[1] = thisDiff[1].slice(0, -1);
+    }
+
+    if (lastEnd && thisTop && this.isHighSurrogate(lastEnd) && this.isLowSurrogate(thisTop)) {
+      thisDiff[1] = lastEnd + thisDiff[1];
+    }
+
+    lastEnd = thisEnd;
+
     switch (diffs[x][0]) {
       case DIFF_INSERT:
         text[x] = '+' + encodeURI(diffs[x][1]);
diff --git a/javascript/tests/diff_match_patch_test.js b/javascript/tests/diff_match_patch_test.js
index 109e56a..c48f3bb 100644
--- a/javascript/tests/diff_match_patch_test.js
+++ b/javascript/tests/diff_match_patch_test.js
@@ -492,6 +492,64 @@ function testDiffDelta() {
   // Convert delta string into a diff.
   assertEquivalent(diffs, dmp.diff_fromDelta(text1, delta));
 
+  diffs = [[DIFF_EQUAL, '\ud83d\ude4b\ud83d'], [DIFF_INSERT, '\ude4c\ud83d'], [DIFF_EQUAL, '\ude4b']];
+  try {
+    delta = dmp.diff_toDelta(diffs);
+    assertEquals('=2\t+%F0%9F%99%8C\t=2', delta);
+  } catch ( e ) {
+    assertEquals(false, true);
+  }
+
+  (function(){
+    const originalText = `U+1F17x	🅰️	🅱️		🅾️	🅿️ safhawifhkw
+    U+1F18x															🆎	
+    0	1	2	3	4	5	6	7	8	9	A	B	C	D	E	F
+    U+1F19x		🆑	🆒	🆓	🆔	🆕	🆖	🆗	🆘	🆙	🆚					
+    U+1F20x		🈁	🈂️							sfss.,_||saavvvbbds						
+    U+1F21x	🈚					
+    U+1F22x			🈯
+    U+1F23x			🈲	🈳	🈴	🈵	🈶	🈷️	🈸	🈹	🈺					
+    U+1F25x	🉐	🉑		
+    U+1F30x	🌀	🌁	🌂	🌃	🌄	🌅	🌆	🌇	🌈	🌉	🌊	🌋	🌌	🌍	🌎	🌏
+    U+1F31x	🌐	🌑	🌒	🌓	🌔	🌕	🌖	🌗	🌘	🌙	🌚	🌛	🌜	🌝	🌞	`;
+
+    // applies some random edits to string and returns new, edited string
+    function applyRandomTextEdit(text) {
+      let textArr = [...text];
+      let r = Math.random();
+      if(r < 1/3) { // swap
+      let swapCount = Math.floor(Math.random()*5);
+        for(let i = 0; i < swapCount; i++) {
+        let swapPos1 = Math.floor(Math.random()*textArr.length);
+          let swapPos2 = Math.floor(Math.random()*textArr.length);
+          let char1 = textArr[swapPos1];
+          let char2 = textArr[swapPos2];
+          textArr[swapPos1] = char2;
+          textArr[swapPos2] = char1;
+        }
+      } else if(r < 2/3) { // remove
+        let removeCount = Math.floor(Math.random()*5);
+        for(let i = 0; i < removeCount; i++) {
+          let removePos = Math.floor(Math.random()*textArr.length);
+          textArr[removePos] = "";
+        }
+      } else { // add
+        let addCount = Math.floor(Math.random()*5);
+        for(let i = 0; i < addCount; i++) {
+          let addPos = Math.floor(Math.random()*textArr.length);
+          let addFromPos = Math.floor(Math.random()*textArr.length);
+          textArr[addPos] = textArr[addPos] + textArr[addFromPos];
+        }
+      }
+      return textArr.join("");
+    }
+
+    for(let i = 0; i < 1000; i++) {
+      newText = applyRandomTextEdit(originalText);
+      dmp.patch_toText(dmp.patch_make(originalText, newText));
+    }
+  });
+
   // Verify pool of unchanged characters.
   diffs = [[DIFF_INSERT, 'A-Z a-z 0-9 - _ . ! ~ * \' ( ) ; / ? : @ & = + $ , # ']];
   var text2 = dmp.diff_text2(diffs);

From 71646fbcff9cab79983bf1aa04dbfabd23d63aa4 Mon Sep 17 00:00:00 2001
From: Dennis Snell <dennis.snell@automattic.com>
Date: Sat, 9 Nov 2019 14:54:38 -0600
Subject: [PATCH 02/34] Add fixes for Java client

---
 .../neil/plaintext/diff_match_patch.java       | 18 ++++++++++++++++++
 .../neil/plaintext/diff_match_patch_test.java  |  4 ++++
 2 files changed, 22 insertions(+)

diff --git a/java/src/name/fraser/neil/plaintext/diff_match_patch.java b/java/src/name/fraser/neil/plaintext/diff_match_patch.java
index 9d07867..c7935ed 100644
--- a/java/src/name/fraser/neil/plaintext/diff_match_patch.java
+++ b/java/src/name/fraser/neil/plaintext/diff_match_patch.java
@@ -19,6 +19,7 @@
 package name.fraser.neil.plaintext;
 
 import java.io.UnsupportedEncodingException;
+import java.lang.Character;
 import java.net.URLDecoder;
 import java.net.URLEncoder;
 import java.util.*;
@@ -1429,7 +1430,24 @@ public int diff_levenshtein(List<Diff> diffs) {
    */
   public String diff_toDelta(List<Diff> diffs) {
     StringBuilder text = new StringBuilder();
+    char lastEnd = 0;
+    boolean isFirst = true;
     for (Diff aDiff : diffs) {
+
+      char thisTop = aDiff.text.charAt(0);
+      char thisEnd = aDiff.text.charAt(aDiff.text.length() - 1);
+
+      if (Character.isHighSurrogate(thisEnd)) {
+        aDiff.text = aDiff.text.substring(0, aDiff.text.length() - 1);
+      }
+
+      if (! isFirst && Character.isHighSurrogate(lastEnd) && Character.isLowSurrogate(thisTop)) {
+        aDiff.text = lastEnd + aDiff.text;
+      }
+
+      isFirst = false;
+      lastEnd = thisEnd;
+
       switch (aDiff.operation) {
       case INSERT:
         try {
diff --git a/java/tests/name/fraser/neil/plaintext/diff_match_patch_test.java b/java/tests/name/fraser/neil/plaintext/diff_match_patch_test.java
index 2f38793..aef98ce 100644
--- a/java/tests/name/fraser/neil/plaintext/diff_match_patch_test.java
+++ b/java/tests/name/fraser/neil/plaintext/diff_match_patch_test.java
@@ -424,6 +424,10 @@ public static void testDiffDelta() {
 
     assertEquals("diff_fromDelta: Unicode.", diffs, dmp.diff_fromDelta(text1, delta));
 
+    diffs = diffList(new Diff(EQUAL, "\ud83d\ude4b\ud83d"), new Diff(INSERT, "\ude4c\ud83d"), new Diff(EQUAL, "\ude4b"));
+    delta = dmp.diff_toDelta(diffs);
+    assertEquals("diff_toDelta: Surrogate Pairs.", "=2\t+%F0%9F%99%8C\t=2", delta);
+
     // Verify pool of unchanged characters.
     diffs = diffList(new Diff(INSERT, "A-Z a-z 0-9 - _ . ! ~ * ' ( ) ; / ? : @ & = + $ , # "));
     String text2 = dmp.diff_text2(diffs);

From 8d2a5f8a8cd4684228eaf5df28654492cb2e7902 Mon Sep 17 00:00:00 2001
From: Dennis Snell <dennis.snell@automattic.com>
Date: Sat, 9 Nov 2019 22:54:25 -0600
Subject: [PATCH 03/34] Add fixes for ObjectiveC

---
 objectivec/DiffMatchPatch.m | 15 +++++++++++++++
 1 file changed, 15 insertions(+)

diff --git a/objectivec/DiffMatchPatch.m b/objectivec/DiffMatchPatch.m
index 580f265..8adb5dc 100755
--- a/objectivec/DiffMatchPatch.m
+++ b/objectivec/DiffMatchPatch.m
@@ -1299,7 +1299,22 @@ - (NSString *)diff_text2:(NSMutableArray *)diffs;
 - (NSString *)diff_toDelta:(NSMutableArray *)diffs;
 {
   NSMutableString *delta = [NSMutableString string];
+  UniChar lastEnd;
   for (Diff *aDiff in diffs) {
+
+    UniChar thisTop = [aDiff.text characterAtIndex:0];
+    UniChar thisEnd = [aDiff.text characterAtIndex:([aDiff.text length]-1)];
+
+    if (CFStringIsSurrogateHighCharacter(thisEnd)) {
+      aDiff.text = [aDiff.text substringToIndex:([aDiff.text length] - 1)];
+    }
+
+    if (nil != lastEnd && CFStringIsSurrogateHighCharacter(lastEnd) && CFStringIsSurrogateLowCharacter(thisTop)) {
+      aDiff.text = [[NSString stringWithFormat:@"%C", lastEnd] stringByAppendingString:aDiff.text];
+    }
+
+    lastEnd = thisEnd;
+
     switch (aDiff.operation) {
       case DIFF_INSERT:
         [delta appendFormat:@"+%@\t", [[aDiff.text diff_stringByAddingPercentEscapesForEncodeUriCompatibility]

From 535e29e8447ec303eb7350db6ceb88333c5ab2f5 Mon Sep 17 00:00:00 2001
From: Dennis Snell <dennis.snell@automattic.com>
Date: Sun, 10 Nov 2019 00:28:26 -0600
Subject: [PATCH 04/34] Add fixes for Python2

---
 python2/diff_match_patch.py            | 25 +++++++++++++++++++++++++
 python2/tests/diff_match_patch_test.py |  4 ++++
 2 files changed, 29 insertions(+)

diff --git a/python2/diff_match_patch.py b/python2/diff_match_patch.py
index 806fe1e..0d0e8a8 100644
--- a/python2/diff_match_patch.py
+++ b/python2/diff_match_patch.py
@@ -28,6 +28,7 @@
 __author__ = 'fraser@google.com (Neil Fraser)'
 
 import re
+import struct
 import sys
 import time
 import urllib
@@ -1135,6 +1136,16 @@ def diff_levenshtein(self, diffs):
     levenshtein += max(insertions, deletions)
     return levenshtein
 
+  @classmethod
+  def is_high_surrogate(cls, utf16be_bytes):
+    c = struct.unpack('>H', utf16be_bytes)[0]
+    return c >= 0xd800 and c <= 0xdbff
+
+  @classmethod
+  def is_low_surrogate(cls, utf16be_bytes):
+    c = struct.unpack('>H', utf16be_bytes)[0]
+    return c >= 0xdc00 and c <= 0xdfff
+
   def diff_toDelta(self, diffs):
     """Crush the diff into an encoded string which describes the operations
     required to transform text1 into text2.
@@ -1148,7 +1159,21 @@ def diff_toDelta(self, diffs):
       Delta text.
     """
     text = []
+    last_end = None
     for (op, data) in diffs:
+      encoded = data.encode('utf-16be')
+      this_top = encoded[0:2]
+      this_end = encoded[-2:]
+
+      if self.is_high_surrogate(this_end):
+        encoded = encoded[0:-2]
+
+      if last_end and self.is_high_surrogate(last_end) and self.is_low_surrogate(this_top):
+        encoded = last_end + encoded
+
+      data = encoded.decode('utf-16be')
+      last_end = this_end
+
       if op == self.DIFF_INSERT:
         # High ascii will raise UnicodeDecodeError.  Use Unicode instead.
         data = data.encode("utf-8")
diff --git a/python2/tests/diff_match_patch_test.py b/python2/tests/diff_match_patch_test.py
index 661a6b6..fc633bc 100644
--- a/python2/tests/diff_match_patch_test.py
+++ b/python2/tests/diff_match_patch_test.py
@@ -441,6 +441,10 @@ def testDiffDelta(self):
     # Convert delta string into a diff.
     self.assertEquals(diffs, self.dmp.diff_fromDelta(text1, delta))
 
+    diffs = [(self.dmp.DIFF_EQUAL, u"\ud83d\ude4b\ud83d"), (self.dmp.DIFF_INSERT, u"\ude4c\ud83d"), (self.dmp.DIFF_EQUAL, u"\ude4b")]
+    delta = self.dmp.diff_toDelta(diffs)
+    self.assertEquals("=2\t+%F0%9F%99%8C\t=2", delta)
+
     # Verify pool of unchanged characters.
     diffs = [(self.dmp.DIFF_INSERT, "A-Z a-z 0-9 - _ . ! ~ * ' ( ) ; / ? : @ & = + $ , # ")]
     text2 = self.dmp.diff_text2(diffs)

From aafbd58d356a1b783e759ec1895c2ffbcc471cb3 Mon Sep 17 00:00:00 2001
From: Dennis Snell <dennis.snell@automattic.com>
Date: Sun, 10 Nov 2019 01:05:47 -0600
Subject: [PATCH 05/34] Add fixes for Python3

---
 python3/diff_match_patch.py            | 24 ++++++++++++++++++++++++
 python3/tests/diff_match_patch_test.py |  5 +++++
 2 files changed, 29 insertions(+)

diff --git a/python3/diff_match_patch.py b/python3/diff_match_patch.py
index cc7f590..e5c52e4 100644
--- a/python3/diff_match_patch.py
+++ b/python3/diff_match_patch.py
@@ -26,6 +26,7 @@
 __author__ = 'fraser@google.com (Neil Fraser)'
 
 import re
+import struct
 import sys
 import time
 import urllib.parse
@@ -1133,6 +1134,16 @@ def diff_levenshtein(self, diffs):
     levenshtein += max(insertions, deletions)
     return levenshtein
 
+  @classmethod
+  def is_high_surrogate(cls, utf16be_bytes):
+    c = struct.unpack('>H', utf16be_bytes)[0]
+    return c >= 0xd800 and c <= 0xdbff
+
+  @classmethod
+  def is_low_surrogate(cls, utf16be_bytes):
+    c = struct.unpack('>H', utf16be_bytes)[0]
+    return c >= 0xdc00 and c <= 0xdfff
+
   def diff_toDelta(self, diffs):
     """Crush the diff into an encoded string which describes the operations
     required to transform text1 into text2.
@@ -1146,7 +1157,20 @@ def diff_toDelta(self, diffs):
       Delta text.
     """
     text = []
+    last_end = None
     for (op, data) in diffs:
+      encoded = data.encode('utf-16be', 'surrogatepass')
+      this_top = encoded[0:2]
+      this_end = encoded[-2:]
+
+      if self.is_high_surrogate(this_end):
+        encoded = encoded[0:-2]
+
+      if last_end and self.is_high_surrogate(last_end) and self.is_low_surrogate(this_top):
+        encoded = last_end + encoded
+
+      data = encoded.decode('utf-16be', 'surrogateescape')
+      last_end = this_end
       if op == self.DIFF_INSERT:
         # High ascii will raise UnicodeDecodeError.  Use Unicode instead.
         data = data.encode("utf-8")
diff --git a/python3/tests/diff_match_patch_test.py b/python3/tests/diff_match_patch_test.py
index 3659d3e..6fa69ad 100644
--- a/python3/tests/diff_match_patch_test.py
+++ b/python3/tests/diff_match_patch_test.py
@@ -18,6 +18,7 @@
 """
 
 import imp
+import json
 import os
 import sys
 import time
@@ -444,6 +445,10 @@ def testDiffDelta(self):
     # Convert delta string into a diff.
     self.assertEqual(diffs, self.dmp.diff_fromDelta(text1, delta))
 
+    diffs = [(self.dmp.DIFF_EQUAL, "\ud83d\ude4b\ud83d"), (self.dmp.DIFF_INSERT, "\ude4c\ud83d"), (self.dmp.DIFF_EQUAL, "\ude4b")]
+    delta = self.dmp.diff_toDelta(diffs)
+    self.assertEquals("=2\t+%F0%9F%99%8C\t=2", delta)
+
     # Verify pool of unchanged characters.
     diffs = [(self.dmp.DIFF_INSERT, "A-Z a-z 0-9 - _ . ! ~ * ' ( ) ; / ? : @ & = + $ , # ")]
     text2 = self.dmp.diff_text2(diffs)

From 4fc00732de199b38b5e1ed18e8c465a75a2772c2 Mon Sep 17 00:00:00 2001
From: Dennis Snell <dennis.snell@automattic.com>
Date: Sun, 10 Nov 2019 01:20:34 -0600
Subject: [PATCH 06/34] Add fixes for Python3 and fix counter in Python2

---
 python2/diff_match_patch.py            | 4 ++--
 python3/diff_match_patch.py            | 4 ++--
 python3/tests/diff_match_patch_test.py | 2 +-
 3 files changed, 5 insertions(+), 5 deletions(-)

diff --git a/python2/diff_match_patch.py b/python2/diff_match_patch.py
index 0d0e8a8..d859753 100644
--- a/python2/diff_match_patch.py
+++ b/python2/diff_match_patch.py
@@ -1179,9 +1179,9 @@ def diff_toDelta(self, diffs):
         data = data.encode("utf-8")
         text.append("+" + urllib.quote(data, "!~*'();/?:@&=+$,# "))
       elif op == self.DIFF_DELETE:
-        text.append("-%d" % len(data))
+        text.append("-%d" % (len(data.encode('utf-16be')) // 2))
       elif op == self.DIFF_EQUAL:
-        text.append("=%d" % len(data))
+        text.append("=%d" % (len(data.encode('utf-16be')) // 2))
     return "\t".join(text)
 
   def diff_fromDelta(self, text1, delta):
diff --git a/python3/diff_match_patch.py b/python3/diff_match_patch.py
index e5c52e4..5253c8b 100644
--- a/python3/diff_match_patch.py
+++ b/python3/diff_match_patch.py
@@ -1176,9 +1176,9 @@ def diff_toDelta(self, diffs):
         data = data.encode("utf-8")
         text.append("+" + urllib.parse.quote(data, "!~*'();/?:@&=+$,# "))
       elif op == self.DIFF_DELETE:
-        text.append("-%d" % len(data))
+        text.append("-%d" % (len(data.encode('utf-16-be')) // 2))
       elif op == self.DIFF_EQUAL:
-        text.append("=%d" % len(data))
+        text.append("=%d" % (len(data.encode('utf-16-be')) // 2))
     return "\t".join(text)
 
   def diff_fromDelta(self, text1, delta):
diff --git a/python3/tests/diff_match_patch_test.py b/python3/tests/diff_match_patch_test.py
index 6fa69ad..e8bae30 100644
--- a/python3/tests/diff_match_patch_test.py
+++ b/python3/tests/diff_match_patch_test.py
@@ -447,7 +447,7 @@ def testDiffDelta(self):
 
     diffs = [(self.dmp.DIFF_EQUAL, "\ud83d\ude4b\ud83d"), (self.dmp.DIFF_INSERT, "\ude4c\ud83d"), (self.dmp.DIFF_EQUAL, "\ude4b")]
     delta = self.dmp.diff_toDelta(diffs)
-    self.assertEquals("=2\t+%F0%9F%99%8C\t=2", delta)
+    self.assertEqual("=2\t+%F0%9F%99%8C\t=2", delta)
 
     # Verify pool of unchanged characters.
     diffs = [(self.dmp.DIFF_INSERT, "A-Z a-z 0-9 - _ . ! ~ * ' ( ) ; / ? : @ & = + $ , # ")]

From d0a578f152bc7099bc2fd664be49f16b58a97d96 Mon Sep 17 00:00:00 2001
From: Dennis Snell <dennis.snell@automattic.com>
Date: Sun, 10 Nov 2019 10:56:35 -0600
Subject: [PATCH 07/34] Adjust Python3 code

I'm not sure that I made the right assumptions about Python3's Unicode
handling when I made the first patch to it.

By constructing the specific `diffs` output I created a sequence of code
units that `diff_main` in Python3 would _not_ have made because it's
operating on Unicode code points natively when finding the common
prefix.

Therefore I do not think that the Python3 library experienced this
problem as the others did. Nonetheless it _has_ been reporting the diff
length differently than in other languages and I have left that change
in there.

Of note, it doesn't look like we have true harmony between the languages
despite the appearance of such. The `lua` wiki page makes this clear,
but at least with Python we have the ability to harmonize the meaning of
the lengths and I have done that in this change.
---
 python3/diff_match_patch.py            | 22 ----------------------
 python3/tests/diff_match_patch_test.py |  2 +-
 2 files changed, 1 insertion(+), 23 deletions(-)

diff --git a/python3/diff_match_patch.py b/python3/diff_match_patch.py
index 5253c8b..aa0fc90 100644
--- a/python3/diff_match_patch.py
+++ b/python3/diff_match_patch.py
@@ -1134,16 +1134,6 @@ def diff_levenshtein(self, diffs):
     levenshtein += max(insertions, deletions)
     return levenshtein
 
-  @classmethod
-  def is_high_surrogate(cls, utf16be_bytes):
-    c = struct.unpack('>H', utf16be_bytes)[0]
-    return c >= 0xd800 and c <= 0xdbff
-
-  @classmethod
-  def is_low_surrogate(cls, utf16be_bytes):
-    c = struct.unpack('>H', utf16be_bytes)[0]
-    return c >= 0xdc00 and c <= 0xdfff
-
   def diff_toDelta(self, diffs):
     """Crush the diff into an encoded string which describes the operations
     required to transform text1 into text2.
@@ -1159,18 +1149,6 @@ def diff_toDelta(self, diffs):
     text = []
     last_end = None
     for (op, data) in diffs:
-      encoded = data.encode('utf-16be', 'surrogatepass')
-      this_top = encoded[0:2]
-      this_end = encoded[-2:]
-
-      if self.is_high_surrogate(this_end):
-        encoded = encoded[0:-2]
-
-      if last_end and self.is_high_surrogate(last_end) and self.is_low_surrogate(this_top):
-        encoded = last_end + encoded
-
-      data = encoded.decode('utf-16be', 'surrogateescape')
-      last_end = this_end
       if op == self.DIFF_INSERT:
         # High ascii will raise UnicodeDecodeError.  Use Unicode instead.
         data = data.encode("utf-8")
diff --git a/python3/tests/diff_match_patch_test.py b/python3/tests/diff_match_patch_test.py
index e8bae30..f88f003 100644
--- a/python3/tests/diff_match_patch_test.py
+++ b/python3/tests/diff_match_patch_test.py
@@ -445,7 +445,7 @@ def testDiffDelta(self):
     # Convert delta string into a diff.
     self.assertEqual(diffs, self.dmp.diff_fromDelta(text1, delta))
 
-    diffs = [(self.dmp.DIFF_EQUAL, "\ud83d\ude4b\ud83d"), (self.dmp.DIFF_INSERT, "\ude4c\ud83d"), (self.dmp.DIFF_EQUAL, "\ude4b")]
+    diffs = self.dmp.diff_main("\U0001F64B\U0001F64B", "\U0001F64B\U0001F64C\U0001F64B")
     delta = self.dmp.diff_toDelta(diffs)
     self.assertEqual("=2\t+%F0%9F%99%8C\t=2", delta)
 

From 08de57e85ba1807e678c800314945759550bcc09 Mon Sep 17 00:00:00 2001
From: Dennis Snell <dennis.snell@automattic.com>
Date: Sun, 10 Nov 2019 12:20:40 -0600
Subject: [PATCH 08/34] Fix reconstructing diff in Python3

---
 python3/diff_match_patch.py            | 11 ++++++-----
 python3/tests/diff_match_patch_test.py |  2 ++
 2 files changed, 8 insertions(+), 5 deletions(-)

diff --git a/python3/diff_match_patch.py b/python3/diff_match_patch.py
index aa0fc90..9fb3e26 100644
--- a/python3/diff_match_patch.py
+++ b/python3/diff_match_patch.py
@@ -1174,7 +1174,8 @@ def diff_fromDelta(self, text1, delta):
       ValueError: If invalid input.
     """
     diffs = []
-    pointer = 0  # Cursor in text1
+    as_utf16 = text1.encode('utf-16-be')
+    pointer = 0  # Cursor in as_utf16
     tokens = delta.split("\t")
     for token in tokens:
       if token == "":
@@ -1193,8 +1194,8 @@ def diff_fromDelta(self, text1, delta):
           raise ValueError("Invalid number in diff_fromDelta: " + param)
         if n < 0:
           raise ValueError("Negative number in diff_fromDelta: " + param)
-        text = text1[pointer : pointer + n]
-        pointer += n
+        text = as_utf16[pointer : pointer + n * 2].decode('utf-16-be')
+        pointer += n * 2
         if token[0] == "=":
           diffs.append((self.DIFF_EQUAL, text))
         else:
@@ -1203,10 +1204,10 @@ def diff_fromDelta(self, text1, delta):
         # Anything else is an error.
         raise ValueError("Invalid diff operation in diff_fromDelta: " +
             token[0])
-    if pointer != len(text1):
+    if pointer != len(as_utf16):
       raise ValueError(
           "Delta length (%d) does not equal source text length (%d)." %
-         (pointer, len(text1)))
+         (pointer, len(as_utf16)))
     return diffs
 
   #  MATCH FUNCTIONS
diff --git a/python3/tests/diff_match_patch_test.py b/python3/tests/diff_match_patch_test.py
index f88f003..9474762 100644
--- a/python3/tests/diff_match_patch_test.py
+++ b/python3/tests/diff_match_patch_test.py
@@ -449,6 +449,8 @@ def testDiffDelta(self):
     delta = self.dmp.diff_toDelta(diffs)
     self.assertEqual("=2\t+%F0%9F%99%8C\t=2", delta)
 
+    self.assertEqual(diffs, self.dmp.diff_fromDelta("\U0001F64B\U0001F64B", "=2\t+%F0%9F%99%8C\t=2"))
+
     # Verify pool of unchanged characters.
     diffs = [(self.dmp.DIFF_INSERT, "A-Z a-z 0-9 - _ . ! ~ * ' ( ) ; / ? : @ & = + $ , # ")]
     text2 = self.dmp.diff_text2(diffs)

From df810f72007c3da7fda2570da8ab18f206eeff6b Mon Sep 17 00:00:00 2001
From: Dennis Snell <dennis.snell@automattic.com>
Date: Mon, 11 Nov 2019 16:20:38 -0600
Subject: [PATCH 09/34] Updates from review feedback

---
 .../name/fraser/neil/plaintext/diff_match_patch.java |  3 +++
 javascript/diff_match_patch_uncompressed.js          |  3 +++
 objectivec/DiffMatchPatch.m                          |  9 ++++++---
 objectivec/Tests/DiffMatchPatchTest.m                | 12 ++++++++++++
 python2/diff_match_patch.py                          |  2 ++
 python3/diff_match_patch.py                          |  1 -
 6 files changed, 26 insertions(+), 4 deletions(-)

diff --git a/java/src/name/fraser/neil/plaintext/diff_match_patch.java b/java/src/name/fraser/neil/plaintext/diff_match_patch.java
index c7935ed..d5ecb2c 100644
--- a/java/src/name/fraser/neil/plaintext/diff_match_patch.java
+++ b/java/src/name/fraser/neil/plaintext/diff_match_patch.java
@@ -1447,6 +1447,9 @@ public String diff_toDelta(List<Diff> diffs) {
 
       isFirst = false;
       lastEnd = thisEnd;
+      if ( aDiff.text.isEmpty() ) {
+        continue;
+      }
 
       switch (aDiff.operation) {
       case INSERT:
diff --git a/javascript/diff_match_patch_uncompressed.js b/javascript/diff_match_patch_uncompressed.js
index e8bb278..84a78e8 100644
--- a/javascript/diff_match_patch_uncompressed.js
+++ b/javascript/diff_match_patch_uncompressed.js
@@ -1375,6 +1375,9 @@ diff_match_patch.prototype.diff_toDelta = function(diffs) {
     }
 
     lastEnd = thisEnd;
+    if ( 0 === thisDiff[1].length ) {
+      continue;
+    }
 
     switch (diffs[x][0]) {
       case DIFF_INSERT:
diff --git a/objectivec/DiffMatchPatch.m b/objectivec/DiffMatchPatch.m
index 8adb5dc..75efae0 100755
--- a/objectivec/DiffMatchPatch.m
+++ b/objectivec/DiffMatchPatch.m
@@ -1299,7 +1299,7 @@ - (NSString *)diff_text2:(NSMutableArray *)diffs;
 - (NSString *)diff_toDelta:(NSMutableArray *)diffs;
 {
   NSMutableString *delta = [NSMutableString string];
-  UniChar lastEnd;
+  UniChar lastEnd = 0;
   for (Diff *aDiff in diffs) {
 
     UniChar thisTop = [aDiff.text characterAtIndex:0];
@@ -1309,11 +1309,14 @@ - (NSString *)diff_toDelta:(NSMutableArray *)diffs;
       aDiff.text = [aDiff.text substringToIndex:([aDiff.text length] - 1)];
     }
 
-    if (nil != lastEnd && CFStringIsSurrogateHighCharacter(lastEnd) && CFStringIsSurrogateLowCharacter(thisTop)) {
-      aDiff.text = [[NSString stringWithFormat:@"%C", lastEnd] stringByAppendingString:aDiff.text];
+    if (0 != lastEnd && CFStringIsSurrogateHighCharacter(lastEnd) && CFStringIsSurrogateLowCharacter(thisTop)) {
+      aDiff.text = [NSString stringWithFormat:@"%C%@", lastEnd, stringByAppendingString:aDiff.text];
     }
 
     lastEnd = thisEnd;
+    if (0 == [aDiff.text length]) {
+      continue;
+    }
 
     switch (aDiff.operation) {
       case DIFF_INSERT:
diff --git a/objectivec/Tests/DiffMatchPatchTest.m b/objectivec/Tests/DiffMatchPatchTest.m
index 9697b04..807ae82 100755
--- a/objectivec/Tests/DiffMatchPatchTest.m
+++ b/objectivec/Tests/DiffMatchPatchTest.m
@@ -752,6 +752,18 @@ - (void)test_diff_deltaTest {
 
   XCTAssertEqualObjects(diffs, [dmp diff_fromDeltaWithText:text1 andDelta:delta error:NULL], @"diff_fromDelta: Unicode 2.");
 
+  diffs = [dmp diff_mainOfOldString:@"☺️🖖🏿" andNewString:@"☺️😃🖖🏿"];
+  delta = [dmp diff_toDelta:diffs];
+
+  XCTAssertEqualObjects(delta, @"=2\t+%F0%9F%98%83\t=4", @"Delta should match the expected string");
+
+  diffs = [dmp diff_mainOfOldString:@"☺️🖖🏿" andNewString:@"☺️😃🖖🏿"];
+  patches = [dmp patch_makeFromDiffs:diffs];
+  expectedResult = [dmp patch_apply:patches toString:@"☺️🖖🏿"];
+
+  expectedString = [result firstObject];
+  XCTAssertEqualObjects(edited, expectedString, @"Output String should match the Edited one!");
+
   // Verify pool of unchanged characters.
   diffs = [NSMutableArray arrayWithObject:
        [Diff diffWithOperation:DIFF_INSERT andText:@"A-Z a-z 0-9 - _ . ! ~ * ' ( ) ; / ? : @ & = + $ , # "]];
diff --git a/python2/diff_match_patch.py b/python2/diff_match_patch.py
index d859753..71cbd19 100644
--- a/python2/diff_match_patch.py
+++ b/python2/diff_match_patch.py
@@ -1173,6 +1173,8 @@ def diff_toDelta(self, diffs):
 
       data = encoded.decode('utf-16be')
       last_end = this_end
+      if 0 == len(encoded):
+        continue
 
       if op == self.DIFF_INSERT:
         # High ascii will raise UnicodeDecodeError.  Use Unicode instead.
diff --git a/python3/diff_match_patch.py b/python3/diff_match_patch.py
index 9fb3e26..99aa853 100644
--- a/python3/diff_match_patch.py
+++ b/python3/diff_match_patch.py
@@ -1147,7 +1147,6 @@ def diff_toDelta(self, diffs):
       Delta text.
     """
     text = []
-    last_end = None
     for (op, data) in diffs:
       if op == self.DIFF_INSERT:
         # High ascii will raise UnicodeDecodeError.  Use Unicode instead.

From 1d45818a42eb6dd3b3471f2a1d9943fbbc173fcc Mon Sep 17 00:00:00 2001
From: Dennis Snell <dennis.snell@automattic.com>
Date: Mon, 11 Nov 2019 16:39:39 -0600
Subject: [PATCH 10/34] fixup! Updates from review feedback

---
 objectivec/DiffMatchPatch.m | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/objectivec/DiffMatchPatch.m b/objectivec/DiffMatchPatch.m
index 75efae0..495a07b 100755
--- a/objectivec/DiffMatchPatch.m
+++ b/objectivec/DiffMatchPatch.m
@@ -1310,7 +1310,7 @@ - (NSString *)diff_toDelta:(NSMutableArray *)diffs;
     }
 
     if (0 != lastEnd && CFStringIsSurrogateHighCharacter(lastEnd) && CFStringIsSurrogateLowCharacter(thisTop)) {
-      aDiff.text = [NSString stringWithFormat:@"%C%@", lastEnd, stringByAppendingString:aDiff.text];
+      aDiff.text = [NSString stringWithFormat:@"%C%@", lastEnd, aDiff.text];
     }
 
     lastEnd = thisEnd;

From 82c11111e4c3b99633b7d387fd616db24f503dd0 Mon Sep 17 00:00:00 2001
From: Dennis Snell <dennis.snell@automattic.com>
Date: Mon, 11 Nov 2019 16:42:18 -0600
Subject: [PATCH 11/34] fixup! fixup! Updates from review feedback

---
 objectivec/Tests/DiffMatchPatchTest.m | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/objectivec/Tests/DiffMatchPatchTest.m b/objectivec/Tests/DiffMatchPatchTest.m
index 807ae82..2869492 100755
--- a/objectivec/Tests/DiffMatchPatchTest.m
+++ b/objectivec/Tests/DiffMatchPatchTest.m
@@ -758,11 +758,11 @@ - (void)test_diff_deltaTest {
   XCTAssertEqualObjects(delta, @"=2\t+%F0%9F%98%83\t=4", @"Delta should match the expected string");
 
   diffs = [dmp diff_mainOfOldString:@"☺️🖖🏿" andNewString:@"☺️😃🖖🏿"];
-  patches = [dmp patch_makeFromDiffs:diffs];
-  expectedResult = [dmp patch_apply:patches toString:@"☺️🖖🏿"];
+  NSArray *patches = [dmp patch_makeFromDiffs:diffs];
+  NSArray *patchResult = [dmp patch_apply:patches toString:@"☺️🖖🏿"];
 
-  expectedString = [result firstObject];
-  XCTAssertEqualObjects(edited, expectedString, @"Output String should match the Edited one!");
+  expectedString = [patchResult firstObject];
+  XCTAssertEqualObjects(@"☺️😃🖖🏿", expectedString, @"Output String should match the Edited one!");
 
   // Verify pool of unchanged characters.
   diffs = [NSMutableArray arrayWithObject:

From ea303f28cbf41dd7ec27cbf1183c6bdf0ee5d84c Mon Sep 17 00:00:00 2001
From: Dennis Snell <dennis.snell@automattic.com>
Date: Mon, 11 Nov 2019 17:06:52 -0600
Subject: [PATCH 12/34] Rebuild compressed JavaScript with Closure Compiler

```bash
java \
  -jar path/to/closure-compiler-v20191027.jar \
  --js_output_file=diff_match_patch.js \
  diff_match_patch_uncompressed.js
```
---
 javascript/diff_match_patch.js | 102 ++++++++++++++++-----------------
 1 file changed, 51 insertions(+), 51 deletions(-)

diff --git a/javascript/diff_match_patch.js b/javascript/diff_match_patch.js
index 2fe320a..7fce1db 100644
--- a/javascript/diff_match_patch.js
+++ b/javascript/diff_match_patch.js
@@ -1,55 +1,55 @@
 var diff_match_patch=function(){this.Diff_Timeout=1;this.Diff_EditCost=4;this.Match_Threshold=.5;this.Match_Distance=1E3;this.Patch_DeleteThreshold=.5;this.Patch_Margin=4;this.Match_MaxBits=32},DIFF_DELETE=-1,DIFF_INSERT=1,DIFF_EQUAL=0;diff_match_patch.Diff=function(a,b){this[0]=a;this[1]=b};diff_match_patch.Diff.prototype.length=2;diff_match_patch.Diff.prototype.toString=function(){return this[0]+","+this[1]};
-diff_match_patch.prototype.diff_main=function(a,b,c,d){"undefined"==typeof d&&(d=0>=this.Diff_Timeout?Number.MAX_VALUE:(new Date).getTime()+1E3*this.Diff_Timeout);if(null==a||null==b)throw Error("Null input. (diff_main)");if(a==b)return a?[new diff_match_patch.Diff(DIFF_EQUAL,a)]:[];"undefined"==typeof c&&(c=!0);var e=c,f=this.diff_commonPrefix(a,b);c=a.substring(0,f);a=a.substring(f);b=b.substring(f);f=this.diff_commonSuffix(a,b);var g=a.substring(a.length-f);a=a.substring(0,a.length-f);b=b.substring(0,
-b.length-f);a=this.diff_compute_(a,b,e,d);c&&a.unshift(new diff_match_patch.Diff(DIFF_EQUAL,c));g&&a.push(new diff_match_patch.Diff(DIFF_EQUAL,g));this.diff_cleanupMerge(a);return a};
-diff_match_patch.prototype.diff_compute_=function(a,b,c,d){if(!a)return[new diff_match_patch.Diff(DIFF_INSERT,b)];if(!b)return[new diff_match_patch.Diff(DIFF_DELETE,a)];var e=a.length>b.length?a:b,f=a.length>b.length?b:a,g=e.indexOf(f);return-1!=g?(c=[new diff_match_patch.Diff(DIFF_INSERT,e.substring(0,g)),new diff_match_patch.Diff(DIFF_EQUAL,f),new diff_match_patch.Diff(DIFF_INSERT,e.substring(g+f.length))],a.length>b.length&&(c[0][0]=c[2][0]=DIFF_DELETE),c):1==f.length?[new diff_match_patch.Diff(DIFF_DELETE,
-a),new diff_match_patch.Diff(DIFF_INSERT,b)]:(e=this.diff_halfMatch_(a,b))?(b=e[1],f=e[3],a=e[4],e=this.diff_main(e[0],e[2],c,d),c=this.diff_main(b,f,c,d),e.concat([new diff_match_patch.Diff(DIFF_EQUAL,a)],c)):c&&100<a.length&&100<b.length?this.diff_lineMode_(a,b,d):this.diff_bisect_(a,b,d)};
-diff_match_patch.prototype.diff_lineMode_=function(a,b,c){var d=this.diff_linesToChars_(a,b);a=d.chars1;b=d.chars2;d=d.lineArray;a=this.diff_main(a,b,!1,c);this.diff_charsToLines_(a,d);this.diff_cleanupSemantic(a);a.push(new diff_match_patch.Diff(DIFF_EQUAL,""));for(var e=d=b=0,f="",g="";b<a.length;){switch(a[b][0]){case DIFF_INSERT:e++;g+=a[b][1];break;case DIFF_DELETE:d++;f+=a[b][1];break;case DIFF_EQUAL:if(1<=d&&1<=e){a.splice(b-d-e,d+e);b=b-d-e;d=this.diff_main(f,g,!1,c);for(e=d.length-1;0<=e;e--)a.splice(b,
-0,d[e]);b+=d.length}d=e=0;g=f=""}b++}a.pop();return a};
-diff_match_patch.prototype.diff_bisect_=function(a,b,c){for(var d=a.length,e=b.length,f=Math.ceil((d+e)/2),g=2*f,h=Array(g),l=Array(g),k=0;k<g;k++)h[k]=-1,l[k]=-1;h[f+1]=0;l[f+1]=0;k=d-e;for(var m=0!=k%2,p=0,x=0,w=0,q=0,t=0;t<f&&!((new Date).getTime()>c);t++){for(var v=-t+p;v<=t-x;v+=2){var n=f+v;var r=v==-t||v!=t&&h[n-1]<h[n+1]?h[n+1]:h[n-1]+1;for(var y=r-v;r<d&&y<e&&a.charAt(r)==b.charAt(y);)r++,y++;h[n]=r;if(r>d)x+=2;else if(y>e)p+=2;else if(m&&(n=f+k-v,0<=n&&n<g&&-1!=l[n])){var u=d-l[n];if(r>=
-u)return this.diff_bisectSplit_(a,b,r,y,c)}}for(v=-t+w;v<=t-q;v+=2){n=f+v;u=v==-t||v!=t&&l[n-1]<l[n+1]?l[n+1]:l[n-1]+1;for(r=u-v;u<d&&r<e&&a.charAt(d-u-1)==b.charAt(e-r-1);)u++,r++;l[n]=u;if(u>d)q+=2;else if(r>e)w+=2;else if(!m&&(n=f+k-v,0<=n&&n<g&&-1!=h[n]&&(r=h[n],y=f+r-n,u=d-u,r>=u)))return this.diff_bisectSplit_(a,b,r,y,c)}}return[new diff_match_patch.Diff(DIFF_DELETE,a),new diff_match_patch.Diff(DIFF_INSERT,b)]};
-diff_match_patch.prototype.diff_bisectSplit_=function(a,b,c,d,e){var f=a.substring(0,c),g=b.substring(0,d);a=a.substring(c);b=b.substring(d);f=this.diff_main(f,g,!1,e);e=this.diff_main(a,b,!1,e);return f.concat(e)};
-diff_match_patch.prototype.diff_linesToChars_=function(a,b){function c(a){for(var b="",c=0,g=-1,h=d.length;g<a.length-1;){g=a.indexOf("\n",c);-1==g&&(g=a.length-1);var l=a.substring(c,g+1);(e.hasOwnProperty?e.hasOwnProperty(l):void 0!==e[l])?b+=String.fromCharCode(e[l]):(h==f&&(l=a.substring(c),g=a.length),b+=String.fromCharCode(h),e[l]=h,d[h++]=l);c=g+1}return b}var d=[],e={};d[0]="";var f=4E4,g=c(a);f=65535;var h=c(b);return{chars1:g,chars2:h,lineArray:d}};
-diff_match_patch.prototype.diff_charsToLines_=function(a,b){for(var c=0;c<a.length;c++){for(var d=a[c][1],e=[],f=0;f<d.length;f++)e[f]=b[d.charCodeAt(f)];a[c][1]=e.join("")}};diff_match_patch.prototype.diff_commonPrefix=function(a,b){if(!a||!b||a.charAt(0)!=b.charAt(0))return 0;for(var c=0,d=Math.min(a.length,b.length),e=d,f=0;c<e;)a.substring(f,e)==b.substring(f,e)?f=c=e:d=e,e=Math.floor((d-c)/2+c);return e};
-diff_match_patch.prototype.diff_commonSuffix=function(a,b){if(!a||!b||a.charAt(a.length-1)!=b.charAt(b.length-1))return 0;for(var c=0,d=Math.min(a.length,b.length),e=d,f=0;c<e;)a.substring(a.length-e,a.length-f)==b.substring(b.length-e,b.length-f)?f=c=e:d=e,e=Math.floor((d-c)/2+c);return e};
-diff_match_patch.prototype.diff_commonOverlap_=function(a,b){var c=a.length,d=b.length;if(0==c||0==d)return 0;c>d?a=a.substring(c-d):c<d&&(b=b.substring(0,c));c=Math.min(c,d);if(a==b)return c;d=0;for(var e=1;;){var f=a.substring(c-e);f=b.indexOf(f);if(-1==f)return d;e+=f;if(0==f||a.substring(c-e)==b.substring(0,e))d=e,e++}};
-diff_match_patch.prototype.diff_halfMatch_=function(a,b){function c(a,b,c){for(var d=a.substring(c,c+Math.floor(a.length/4)),e=-1,g="",h,k,l,m;-1!=(e=b.indexOf(d,e+1));){var p=f.diff_commonPrefix(a.substring(c),b.substring(e)),u=f.diff_commonSuffix(a.substring(0,c),b.substring(0,e));g.length<u+p&&(g=b.substring(e-u,e)+b.substring(e,e+p),h=a.substring(0,c-u),k=a.substring(c+p),l=b.substring(0,e-u),m=b.substring(e+p))}return 2*g.length>=a.length?[h,k,l,m,g]:null}if(0>=this.Diff_Timeout)return null;
-var d=a.length>b.length?a:b,e=a.length>b.length?b:a;if(4>d.length||2*e.length<d.length)return null;var f=this,g=c(d,e,Math.ceil(d.length/4));d=c(d,e,Math.ceil(d.length/2));if(g||d)g=d?g?g[4].length>d[4].length?g:d:d:g;else return null;if(a.length>b.length){d=g[0];e=g[1];var h=g[2];var l=g[3]}else h=g[0],l=g[1],d=g[2],e=g[3];return[d,e,h,l,g[4]]};
-diff_match_patch.prototype.diff_cleanupSemantic=function(a){for(var b=!1,c=[],d=0,e=null,f=0,g=0,h=0,l=0,k=0;f<a.length;)a[f][0]==DIFF_EQUAL?(c[d++]=f,g=l,h=k,k=l=0,e=a[f][1]):(a[f][0]==DIFF_INSERT?l+=a[f][1].length:k+=a[f][1].length,e&&e.length<=Math.max(g,h)&&e.length<=Math.max(l,k)&&(a.splice(c[d-1],0,new diff_match_patch.Diff(DIFF_DELETE,e)),a[c[d-1]+1][0]=DIFF_INSERT,d--,d--,f=0<d?c[d-1]:-1,k=l=h=g=0,e=null,b=!0)),f++;b&&this.diff_cleanupMerge(a);this.diff_cleanupSemanticLossless(a);for(f=1;f<
-a.length;){if(a[f-1][0]==DIFF_DELETE&&a[f][0]==DIFF_INSERT){b=a[f-1][1];c=a[f][1];d=this.diff_commonOverlap_(b,c);e=this.diff_commonOverlap_(c,b);if(d>=e){if(d>=b.length/2||d>=c.length/2)a.splice(f,0,new diff_match_patch.Diff(DIFF_EQUAL,c.substring(0,d))),a[f-1][1]=b.substring(0,b.length-d),a[f+1][1]=c.substring(d),f++}else if(e>=b.length/2||e>=c.length/2)a.splice(f,0,new diff_match_patch.Diff(DIFF_EQUAL,b.substring(0,e))),a[f-1][0]=DIFF_INSERT,a[f-1][1]=c.substring(0,c.length-e),a[f+1][0]=DIFF_DELETE,
+diff_match_patch.prototype.diff_main=function(a,b,d,c){"undefined"==typeof c&&(c=0>=this.Diff_Timeout?Number.MAX_VALUE:(new Date).getTime()+1E3*this.Diff_Timeout);if(null==a||null==b)throw Error("Null input. (diff_main)");if(a==b)return a?[new diff_match_patch.Diff(DIFF_EQUAL,a)]:[];"undefined"==typeof d&&(d=!0);var e=d,f=this.diff_commonPrefix(a,b);d=a.substring(0,f);a=a.substring(f);b=b.substring(f);f=this.diff_commonSuffix(a,b);var g=a.substring(a.length-f);a=a.substring(0,a.length-f);b=b.substring(0,
+b.length-f);a=this.diff_compute_(a,b,e,c);d&&a.unshift(new diff_match_patch.Diff(DIFF_EQUAL,d));g&&a.push(new diff_match_patch.Diff(DIFF_EQUAL,g));this.diff_cleanupMerge(a);return a};
+diff_match_patch.prototype.diff_compute_=function(a,b,d,c){if(!a)return[new diff_match_patch.Diff(DIFF_INSERT,b)];if(!b)return[new diff_match_patch.Diff(DIFF_DELETE,a)];var e=a.length>b.length?a:b,f=a.length>b.length?b:a,g=e.indexOf(f);return-1!=g?(d=[new diff_match_patch.Diff(DIFF_INSERT,e.substring(0,g)),new diff_match_patch.Diff(DIFF_EQUAL,f),new diff_match_patch.Diff(DIFF_INSERT,e.substring(g+f.length))],a.length>b.length&&(d[0][0]=d[2][0]=DIFF_DELETE),d):1==f.length?[new diff_match_patch.Diff(DIFF_DELETE,
+a),new diff_match_patch.Diff(DIFF_INSERT,b)]:(e=this.diff_halfMatch_(a,b))?(b=e[1],f=e[3],a=e[4],e=this.diff_main(e[0],e[2],d,c),d=this.diff_main(b,f,d,c),e.concat([new diff_match_patch.Diff(DIFF_EQUAL,a)],d)):d&&100<a.length&&100<b.length?this.diff_lineMode_(a,b,c):this.diff_bisect_(a,b,c)};
+diff_match_patch.prototype.diff_lineMode_=function(a,b,d){var c=this.diff_linesToChars_(a,b);a=c.chars1;b=c.chars2;c=c.lineArray;a=this.diff_main(a,b,!1,d);this.diff_charsToLines_(a,c);this.diff_cleanupSemantic(a);a.push(new diff_match_patch.Diff(DIFF_EQUAL,""));for(var e=c=b=0,f="",g="";b<a.length;){switch(a[b][0]){case DIFF_INSERT:e++;g+=a[b][1];break;case DIFF_DELETE:c++;f+=a[b][1];break;case DIFF_EQUAL:if(1<=c&&1<=e){a.splice(b-c-e,c+e);b=b-c-e;c=this.diff_main(f,g,!1,d);for(e=c.length-1;0<=e;e--)a.splice(b,
+0,c[e]);b+=c.length}c=e=0;g=f=""}b++}a.pop();return a};
+diff_match_patch.prototype.diff_bisect_=function(a,b,d){for(var c=a.length,e=b.length,f=Math.ceil((c+e)/2),g=2*f,h=Array(g),l=Array(g),k=0;k<g;k++)h[k]=-1,l[k]=-1;h[f+1]=0;l[f+1]=0;k=c-e;for(var m=0!=k%2,p=0,x=0,w=0,t=0,u=0;u<f&&!((new Date).getTime()>d);u++){for(var r=-u+p;r<=u-x;r+=2){var n=f+r;var q=r==-u||r!=u&&h[n-1]<h[n+1]?h[n+1]:h[n-1]+1;for(var y=q-r;q<c&&y<e&&a.charAt(q)==b.charAt(y);)q++,y++;h[n]=q;if(q>c)x+=2;else if(y>e)p+=2;else if(m&&(n=f+k-r,0<=n&&n<g&&-1!=l[n])){var v=c-l[n];if(q>=
+v)return this.diff_bisectSplit_(a,b,q,y,d)}}for(r=-u+w;r<=u-t;r+=2){n=f+r;v=r==-u||r!=u&&l[n-1]<l[n+1]?l[n+1]:l[n-1]+1;for(q=v-r;v<c&&q<e&&a.charAt(c-v-1)==b.charAt(e-q-1);)v++,q++;l[n]=v;if(v>c)t+=2;else if(q>e)w+=2;else if(!m&&(n=f+k-r,0<=n&&n<g&&-1!=h[n]&&(q=h[n],y=f+q-n,v=c-v,q>=v)))return this.diff_bisectSplit_(a,b,q,y,d)}}return[new diff_match_patch.Diff(DIFF_DELETE,a),new diff_match_patch.Diff(DIFF_INSERT,b)]};
+diff_match_patch.prototype.diff_bisectSplit_=function(a,b,d,c,e){var f=a.substring(0,d),g=b.substring(0,c);a=a.substring(d);b=b.substring(c);f=this.diff_main(f,g,!1,e);e=this.diff_main(a,b,!1,e);return f.concat(e)};
+diff_match_patch.prototype.diff_linesToChars_=function(a,b){function d(a){for(var b="",d=0,g=-1,m=c.length;g<a.length-1;){g=a.indexOf("\n",d);-1==g&&(g=a.length-1);var p=a.substring(d,g+1);(e.hasOwnProperty?e.hasOwnProperty(p):void 0!==e[p])?b+=String.fromCharCode(e[p]):(m==f&&(p=a.substring(d),g=a.length),b+=String.fromCharCode(m),e[p]=m,c[m++]=p);d=g+1}return b}var c=[],e={};c[0]="";var f=4E4;a=d(a);f=65535;b=d(b);return{chars1:a,chars2:b,lineArray:c}};
+diff_match_patch.prototype.diff_charsToLines_=function(a,b){for(var d=0;d<a.length;d++){for(var c=a[d][1],e=[],f=0;f<c.length;f++)e[f]=b[c.charCodeAt(f)];a[d][1]=e.join("")}};diff_match_patch.prototype.diff_commonPrefix=function(a,b){if(!a||!b||a.charAt(0)!=b.charAt(0))return 0;for(var d=0,c=Math.min(a.length,b.length),e=c,f=0;d<e;)a.substring(f,e)==b.substring(f,e)?f=d=e:c=e,e=Math.floor((c-d)/2+d);return e};
+diff_match_patch.prototype.diff_commonSuffix=function(a,b){if(!a||!b||a.charAt(a.length-1)!=b.charAt(b.length-1))return 0;for(var d=0,c=Math.min(a.length,b.length),e=c,f=0;d<e;)a.substring(a.length-e,a.length-f)==b.substring(b.length-e,b.length-f)?f=d=e:c=e,e=Math.floor((c-d)/2+d);return e};
+diff_match_patch.prototype.diff_commonOverlap_=function(a,b){var d=a.length,c=b.length;if(0==d||0==c)return 0;d>c?a=a.substring(d-c):d<c&&(b=b.substring(0,d));d=Math.min(d,c);if(a==b)return d;c=0;for(var e=1;;){var f=a.substring(d-e);f=b.indexOf(f);if(-1==f)return c;e+=f;if(0==f||a.substring(d-e)==b.substring(0,e))c=e,e++}};
+diff_match_patch.prototype.diff_halfMatch_=function(a,b){function d(a,b,c){for(var d=a.substring(c,c+Math.floor(a.length/4)),e=-1,g="",h,k,l,r;-1!=(e=b.indexOf(d,e+1));){var n=f.diff_commonPrefix(a.substring(c),b.substring(e)),q=f.diff_commonSuffix(a.substring(0,c),b.substring(0,e));g.length<q+n&&(g=b.substring(e-q,e)+b.substring(e,e+n),h=a.substring(0,c-q),k=a.substring(c+n),l=b.substring(0,e-q),r=b.substring(e+n))}return 2*g.length>=a.length?[h,k,l,r,g]:null}if(0>=this.Diff_Timeout)return null;
+var c=a.length>b.length?a:b,e=a.length>b.length?b:a;if(4>c.length||2*e.length<c.length)return null;var f=this,g=d(c,e,Math.ceil(c.length/4));c=d(c,e,Math.ceil(c.length/2));if(g||c)g=c?g?g[4].length>c[4].length?g:c:c:g;else return null;a.length>b.length?(a=g[0],b=g[1],c=g[2],e=g[3]):(c=g[0],e=g[1],a=g[2],b=g[3]);return[a,b,c,e,g[4]]};
+diff_match_patch.prototype.diff_cleanupSemantic=function(a){for(var b=!1,d=[],c=0,e=null,f=0,g=0,h=0,l=0,k=0;f<a.length;)a[f][0]==DIFF_EQUAL?(d[c++]=f,g=l,h=k,k=l=0,e=a[f][1]):(a[f][0]==DIFF_INSERT?l+=a[f][1].length:k+=a[f][1].length,e&&e.length<=Math.max(g,h)&&e.length<=Math.max(l,k)&&(a.splice(d[c-1],0,new diff_match_patch.Diff(DIFF_DELETE,e)),a[d[c-1]+1][0]=DIFF_INSERT,c--,c--,f=0<c?d[c-1]:-1,k=l=h=g=0,e=null,b=!0)),f++;b&&this.diff_cleanupMerge(a);this.diff_cleanupSemanticLossless(a);for(f=1;f<
+a.length;){if(a[f-1][0]==DIFF_DELETE&&a[f][0]==DIFF_INSERT){b=a[f-1][1];d=a[f][1];c=this.diff_commonOverlap_(b,d);e=this.diff_commonOverlap_(d,b);if(c>=e){if(c>=b.length/2||c>=d.length/2)a.splice(f,0,new diff_match_patch.Diff(DIFF_EQUAL,d.substring(0,c))),a[f-1][1]=b.substring(0,b.length-c),a[f+1][1]=d.substring(c),f++}else if(e>=b.length/2||e>=d.length/2)a.splice(f,0,new diff_match_patch.Diff(DIFF_EQUAL,b.substring(0,e))),a[f-1][0]=DIFF_INSERT,a[f-1][1]=d.substring(0,d.length-e),a[f+1][0]=DIFF_DELETE,
 a[f+1][1]=b.substring(e),f++;f++}f++}};
-diff_match_patch.prototype.diff_cleanupSemanticLossless=function(a){function b(a,b){if(!a||!b)return 6;var c=a.charAt(a.length-1),d=b.charAt(0),e=c.match(diff_match_patch.nonAlphaNumericRegex_),f=d.match(diff_match_patch.nonAlphaNumericRegex_),g=e&&c.match(diff_match_patch.whitespaceRegex_),h=f&&d.match(diff_match_patch.whitespaceRegex_);c=g&&c.match(diff_match_patch.linebreakRegex_);d=h&&d.match(diff_match_patch.linebreakRegex_);var k=c&&a.match(diff_match_patch.blanklineEndRegex_),l=d&&b.match(diff_match_patch.blanklineStartRegex_);
-return k||l?5:c||d?4:e&&!g&&h?3:g||h?2:e||f?1:0}for(var c=1;c<a.length-1;){if(a[c-1][0]==DIFF_EQUAL&&a[c+1][0]==DIFF_EQUAL){var d=a[c-1][1],e=a[c][1],f=a[c+1][1],g=this.diff_commonSuffix(d,e);if(g){var h=e.substring(e.length-g);d=d.substring(0,d.length-g);e=h+e.substring(0,e.length-g);f=h+f}g=d;h=e;for(var l=f,k=b(d,e)+b(e,f);e.charAt(0)===f.charAt(0);){d+=e.charAt(0);e=e.substring(1)+f.charAt(0);f=f.substring(1);var m=b(d,e)+b(e,f);m>=k&&(k=m,g=d,h=e,l=f)}a[c-1][1]!=g&&(g?a[c-1][1]=g:(a.splice(c-
-1,1),c--),a[c][1]=h,l?a[c+1][1]=l:(a.splice(c+1,1),c--))}c++}};diff_match_patch.nonAlphaNumericRegex_=/[^a-zA-Z0-9]/;diff_match_patch.whitespaceRegex_=/\s/;diff_match_patch.linebreakRegex_=/[\r\n]/;diff_match_patch.blanklineEndRegex_=/\n\r?\n$/;diff_match_patch.blanklineStartRegex_=/^\r?\n\r?\n/;
-diff_match_patch.prototype.diff_cleanupEfficiency=function(a){for(var b=!1,c=[],d=0,e=null,f=0,g=!1,h=!1,l=!1,k=!1;f<a.length;)a[f][0]==DIFF_EQUAL?(a[f][1].length<this.Diff_EditCost&&(l||k)?(c[d++]=f,g=l,h=k,e=a[f][1]):(d=0,e=null),l=k=!1):(a[f][0]==DIFF_DELETE?k=!0:l=!0,e&&(g&&h&&l&&k||e.length<this.Diff_EditCost/2&&3==g+h+l+k)&&(a.splice(c[d-1],0,new diff_match_patch.Diff(DIFF_DELETE,e)),a[c[d-1]+1][0]=DIFF_INSERT,d--,e=null,g&&h?(l=k=!0,d=0):(d--,f=0<d?c[d-1]:-1,l=k=!1),b=!0)),f++;b&&this.diff_cleanupMerge(a)};
-diff_match_patch.prototype.diff_cleanupMerge=function(a){a.push(new diff_match_patch.Diff(DIFF_EQUAL,""));for(var b=0,c=0,d=0,e="",f="",g;b<a.length;)switch(a[b][0]){case DIFF_INSERT:d++;f+=a[b][1];b++;break;case DIFF_DELETE:c++;e+=a[b][1];b++;break;case DIFF_EQUAL:1<c+d?(0!==c&&0!==d&&(g=this.diff_commonPrefix(f,e),0!==g&&(0<b-c-d&&a[b-c-d-1][0]==DIFF_EQUAL?a[b-c-d-1][1]+=f.substring(0,g):(a.splice(0,0,new diff_match_patch.Diff(DIFF_EQUAL,f.substring(0,g))),b++),f=f.substring(g),e=e.substring(g)),
-g=this.diff_commonSuffix(f,e),0!==g&&(a[b][1]=f.substring(f.length-g)+a[b][1],f=f.substring(0,f.length-g),e=e.substring(0,e.length-g))),b-=c+d,a.splice(b,c+d),e.length&&(a.splice(b,0,new diff_match_patch.Diff(DIFF_DELETE,e)),b++),f.length&&(a.splice(b,0,new diff_match_patch.Diff(DIFF_INSERT,f)),b++),b++):0!==b&&a[b-1][0]==DIFF_EQUAL?(a[b-1][1]+=a[b][1],a.splice(b,1)):b++,c=d=0,f=e=""}""===a[a.length-1][1]&&a.pop();c=!1;for(b=1;b<a.length-1;)a[b-1][0]==DIFF_EQUAL&&a[b+1][0]==DIFF_EQUAL&&(a[b][1].substring(a[b][1].length-
-a[b-1][1].length)==a[b-1][1]?(a[b][1]=a[b-1][1]+a[b][1].substring(0,a[b][1].length-a[b-1][1].length),a[b+1][1]=a[b-1][1]+a[b+1][1],a.splice(b-1,1),c=!0):a[b][1].substring(0,a[b+1][1].length)==a[b+1][1]&&(a[b-1][1]+=a[b+1][1],a[b][1]=a[b][1].substring(a[b+1][1].length)+a[b+1][1],a.splice(b+1,1),c=!0)),b++;c&&this.diff_cleanupMerge(a)};
-diff_match_patch.prototype.diff_xIndex=function(a,b){var c=0,d=0,e=0,f=0,g;for(g=0;g<a.length;g++){a[g][0]!==DIFF_INSERT&&(c+=a[g][1].length);a[g][0]!==DIFF_DELETE&&(d+=a[g][1].length);if(c>b)break;e=c;f=d}return a.length!=g&&a[g][0]===DIFF_DELETE?f:f+(b-e)};
-diff_match_patch.prototype.diff_prettyHtml=function(a){for(var b=[],c=/&/g,d=/</g,e=/>/g,f=/\n/g,g=0;g<a.length;g++){var h=a[g][0],l=a[g][1].replace(c,"&amp;").replace(d,"&lt;").replace(e,"&gt;").replace(f,"&para;<br>");switch(h){case DIFF_INSERT:b[g]='<ins style="background:#e6ffe6;">'+l+"</ins>";break;case DIFF_DELETE:b[g]='<del style="background:#ffe6e6;">'+l+"</del>";break;case DIFF_EQUAL:b[g]="<span>"+l+"</span>"}}return b.join("")};
-diff_match_patch.prototype.diff_text1=function(a){for(var b=[],c=0;c<a.length;c++)a[c][0]!==DIFF_INSERT&&(b[c]=a[c][1]);return b.join("")};diff_match_patch.prototype.diff_text2=function(a){for(var b=[],c=0;c<a.length;c++)a[c][0]!==DIFF_DELETE&&(b[c]=a[c][1]);return b.join("")};
-diff_match_patch.prototype.diff_levenshtein=function(a){for(var b=0,c=0,d=0,e=0;e<a.length;e++){var f=a[e][1];switch(a[e][0]){case DIFF_INSERT:c+=f.length;break;case DIFF_DELETE:d+=f.length;break;case DIFF_EQUAL:b+=Math.max(c,d),d=c=0}}return b+=Math.max(c,d)};
-diff_match_patch.prototype.diff_toDelta=function(a){for(var b=[],c=0;c<a.length;c++)switch(a[c][0]){case DIFF_INSERT:b[c]="+"+encodeURI(a[c][1]);break;case DIFF_DELETE:b[c]="-"+a[c][1].length;break;case DIFF_EQUAL:b[c]="="+a[c][1].length}return b.join("\t").replace(/%20/g," ")};
-diff_match_patch.prototype.diff_fromDelta=function(a,b){for(var c=[],d=0,e=0,f=b.split(/\t/g),g=0;g<f.length;g++){var h=f[g].substring(1);switch(f[g].charAt(0)){case "+":try{c[d++]=new diff_match_patch.Diff(DIFF_INSERT,decodeURI(h))}catch(k){throw Error("Illegal escape in diff_fromDelta: "+h);}break;case "-":case "=":var l=parseInt(h,10);if(isNaN(l)||0>l)throw Error("Invalid number in diff_fromDelta: "+h);h=a.substring(e,e+=l);"="==f[g].charAt(0)?c[d++]=new diff_match_patch.Diff(DIFF_EQUAL,h):c[d++]=
-new diff_match_patch.Diff(DIFF_DELETE,h);break;default:if(f[g])throw Error("Invalid diff operation in diff_fromDelta: "+f[g]);}}if(e!=a.length)throw Error("Delta length ("+e+") does not equal source text length ("+a.length+").");return c};diff_match_patch.prototype.match_main=function(a,b,c){if(null==a||null==b||null==c)throw Error("Null input. (match_main)");c=Math.max(0,Math.min(c,a.length));return a==b?0:a.length?a.substring(c,c+b.length)==b?c:this.match_bitap_(a,b,c):-1};
-diff_match_patch.prototype.match_bitap_=function(a,b,c){function d(a,d){var e=a/b.length,g=Math.abs(c-d);return f.Match_Distance?e+g/f.Match_Distance:g?1:e}if(b.length>this.Match_MaxBits)throw Error("Pattern too long for this browser.");var e=this.match_alphabet_(b),f=this,g=this.Match_Threshold,h=a.indexOf(b,c);-1!=h&&(g=Math.min(d(0,h),g),h=a.lastIndexOf(b,c+b.length),-1!=h&&(g=Math.min(d(0,h),g)));var l=1<<b.length-1;h=-1;for(var k,m,p=b.length+a.length,x,w=0;w<b.length;w++){k=0;for(m=p;k<m;)d(w,
-c+m)<=g?k=m:p=m,m=Math.floor((p-k)/2+k);p=m;k=Math.max(1,c-m+1);var q=Math.min(c+m,a.length)+b.length;m=Array(q+2);for(m[q+1]=(1<<w)-1;q>=k;q--){var t=e[a.charAt(q-1)];m[q]=0===w?(m[q+1]<<1|1)&t:(m[q+1]<<1|1)&t|(x[q+1]|x[q])<<1|1|x[q+1];if(m[q]&l&&(t=d(w,q-1),t<=g))if(g=t,h=q-1,h>c)k=Math.max(1,2*c-h);else break}if(d(w+1,c)>g)break;x=m}return h};
-diff_match_patch.prototype.match_alphabet_=function(a){for(var b={},c=0;c<a.length;c++)b[a.charAt(c)]=0;for(c=0;c<a.length;c++)b[a.charAt(c)]|=1<<a.length-c-1;return b};
-diff_match_patch.prototype.patch_addContext_=function(a,b){if(0!=b.length){if(null===a.start2)throw Error("patch not initialized");for(var c=b.substring(a.start2,a.start2+a.length1),d=0;b.indexOf(c)!=b.lastIndexOf(c)&&c.length<this.Match_MaxBits-this.Patch_Margin-this.Patch_Margin;)d+=this.Patch_Margin,c=b.substring(a.start2-d,a.start2+a.length1+d);d+=this.Patch_Margin;(c=b.substring(a.start2-d,a.start2))&&a.diffs.unshift(new diff_match_patch.Diff(DIFF_EQUAL,c));(d=b.substring(a.start2+a.length1,
-a.start2+a.length1+d))&&a.diffs.push(new diff_match_patch.Diff(DIFF_EQUAL,d));a.start1-=c.length;a.start2-=c.length;a.length1+=c.length+d.length;a.length2+=c.length+d.length}};
-diff_match_patch.prototype.patch_make=function(a,b,c){if("string"==typeof a&&"string"==typeof b&&"undefined"==typeof c){var d=a;b=this.diff_main(d,b,!0);2<b.length&&(this.diff_cleanupSemantic(b),this.diff_cleanupEfficiency(b))}else if(a&&"object"==typeof a&&"undefined"==typeof b&&"undefined"==typeof c)b=a,d=this.diff_text1(b);else if("string"==typeof a&&b&&"object"==typeof b&&"undefined"==typeof c)d=a;else if("string"==typeof a&&"string"==typeof b&&c&&"object"==typeof c)d=a,b=c;else throw Error("Unknown call format to patch_make.");
-if(0===b.length)return[];c=[];a=new diff_match_patch.patch_obj;for(var e=0,f=0,g=0,h=d,l=0;l<b.length;l++){var k=b[l][0],m=b[l][1];e||k===DIFF_EQUAL||(a.start1=f,a.start2=g);switch(k){case DIFF_INSERT:a.diffs[e++]=b[l];a.length2+=m.length;d=d.substring(0,g)+m+d.substring(g);break;case DIFF_DELETE:a.length1+=m.length;a.diffs[e++]=b[l];d=d.substring(0,g)+d.substring(g+m.length);break;case DIFF_EQUAL:m.length<=2*this.Patch_Margin&&e&&b.length!=l+1?(a.diffs[e++]=b[l],a.length1+=m.length,a.length2+=m.length):
-m.length>=2*this.Patch_Margin&&e&&(this.patch_addContext_(a,h),c.push(a),a=new diff_match_patch.patch_obj,e=0,h=d,f=g)}k!==DIFF_INSERT&&(f+=m.length);k!==DIFF_DELETE&&(g+=m.length)}e&&(this.patch_addContext_(a,h),c.push(a));return c};
-diff_match_patch.prototype.patch_deepCopy=function(a){for(var b=[],c=0;c<a.length;c++){var d=a[c],e=new diff_match_patch.patch_obj;e.diffs=[];for(var f=0;f<d.diffs.length;f++)e.diffs[f]=new diff_match_patch.Diff(d.diffs[f][0],d.diffs[f][1]);e.start1=d.start1;e.start2=d.start2;e.length1=d.length1;e.length2=d.length2;b[c]=e}return b};
-diff_match_patch.prototype.patch_apply=function(a,b){if(0==a.length)return[b,[]];a=this.patch_deepCopy(a);var c=this.patch_addPadding(a);b=c+b+c;this.patch_splitMax(a);for(var d=0,e=[],f=0;f<a.length;f++){var g=a[f].start2+d,h=this.diff_text1(a[f].diffs),l=-1;if(h.length>this.Match_MaxBits){var k=this.match_main(b,h.substring(0,this.Match_MaxBits),g);-1!=k&&(l=this.match_main(b,h.substring(h.length-this.Match_MaxBits),g+h.length-this.Match_MaxBits),-1==l||k>=l)&&(k=-1)}else k=this.match_main(b,h,
-g);if(-1==k)e[f]=!1,d-=a[f].length2-a[f].length1;else if(e[f]=!0,d=k-g,g=-1==l?b.substring(k,k+h.length):b.substring(k,l+this.Match_MaxBits),h==g)b=b.substring(0,k)+this.diff_text2(a[f].diffs)+b.substring(k+h.length);else if(g=this.diff_main(h,g,!1),h.length>this.Match_MaxBits&&this.diff_levenshtein(g)/h.length>this.Patch_DeleteThreshold)e[f]=!1;else{this.diff_cleanupSemanticLossless(g);h=0;var m;for(l=0;l<a[f].diffs.length;l++){var p=a[f].diffs[l];p[0]!==DIFF_EQUAL&&(m=this.diff_xIndex(g,h));p[0]===
-DIFF_INSERT?b=b.substring(0,k+m)+p[1]+b.substring(k+m):p[0]===DIFF_DELETE&&(b=b.substring(0,k+m)+b.substring(k+this.diff_xIndex(g,h+p[1].length)));p[0]!==DIFF_DELETE&&(h+=p[1].length)}}}b=b.substring(c.length,b.length-c.length);return[b,e]};
-diff_match_patch.prototype.patch_addPadding=function(a){for(var b=this.Patch_Margin,c="",d=1;d<=b;d++)c+=String.fromCharCode(d);for(d=0;d<a.length;d++)a[d].start1+=b,a[d].start2+=b;d=a[0];var e=d.diffs;if(0==e.length||e[0][0]!=DIFF_EQUAL)e.unshift(new diff_match_patch.Diff(DIFF_EQUAL,c)),d.start1-=b,d.start2-=b,d.length1+=b,d.length2+=b;else if(b>e[0][1].length){var f=b-e[0][1].length;e[0][1]=c.substring(e[0][1].length)+e[0][1];d.start1-=f;d.start2-=f;d.length1+=f;d.length2+=f}d=a[a.length-1];e=d.diffs;
-0==e.length||e[e.length-1][0]!=DIFF_EQUAL?(e.push(new diff_match_patch.Diff(DIFF_EQUAL,c)),d.length1+=b,d.length2+=b):b>e[e.length-1][1].length&&(f=b-e[e.length-1][1].length,e[e.length-1][1]+=c.substring(0,f),d.length1+=f,d.length2+=f);return c};
-diff_match_patch.prototype.patch_splitMax=function(a){for(var b=this.Match_MaxBits,c=0;c<a.length;c++)if(!(a[c].length1<=b)){var d=a[c];a.splice(c--,1);for(var e=d.start1,f=d.start2,g="";0!==d.diffs.length;){var h=new diff_match_patch.patch_obj,l=!0;h.start1=e-g.length;h.start2=f-g.length;""!==g&&(h.length1=h.length2=g.length,h.diffs.push(new diff_match_patch.Diff(DIFF_EQUAL,g)));for(;0!==d.diffs.length&&h.length1<b-this.Patch_Margin;){g=d.diffs[0][0];var k=d.diffs[0][1];g===DIFF_INSERT?(h.length2+=
-k.length,f+=k.length,h.diffs.push(d.diffs.shift()),l=!1):g===DIFF_DELETE&&1==h.diffs.length&&h.diffs[0][0]==DIFF_EQUAL&&k.length>2*b?(h.length1+=k.length,e+=k.length,l=!1,h.diffs.push(new diff_match_patch.Diff(g,k)),d.diffs.shift()):(k=k.substring(0,b-h.length1-this.Patch_Margin),h.length1+=k.length,e+=k.length,g===DIFF_EQUAL?(h.length2+=k.length,f+=k.length):l=!1,h.diffs.push(new diff_match_patch.Diff(g,k)),k==d.diffs[0][1]?d.diffs.shift():d.diffs[0][1]=d.diffs[0][1].substring(k.length))}g=this.diff_text2(h.diffs);
-g=g.substring(g.length-this.Patch_Margin);k=this.diff_text1(d.diffs).substring(0,this.Patch_Margin);""!==k&&(h.length1+=k.length,h.length2+=k.length,0!==h.diffs.length&&h.diffs[h.diffs.length-1][0]===DIFF_EQUAL?h.diffs[h.diffs.length-1][1]+=k:h.diffs.push(new diff_match_patch.Diff(DIFF_EQUAL,k)));l||a.splice(++c,0,h)}}};diff_match_patch.prototype.patch_toText=function(a){for(var b=[],c=0;c<a.length;c++)b[c]=a[c];return b.join("")};
-diff_match_patch.prototype.patch_fromText=function(a){var b=[];if(!a)return b;a=a.split("\n");for(var c=0,d=/^@@ -(\d+),?(\d*) \+(\d+),?(\d*) @@$/;c<a.length;){var e=a[c].match(d);if(!e)throw Error("Invalid patch string: "+a[c]);var f=new diff_match_patch.patch_obj;b.push(f);f.start1=parseInt(e[1],10);""===e[2]?(f.start1--,f.length1=1):"0"==e[2]?f.length1=0:(f.start1--,f.length1=parseInt(e[2],10));f.start2=parseInt(e[3],10);""===e[4]?(f.start2--,f.length2=1):"0"==e[4]?f.length2=0:(f.start2--,f.length2=
-parseInt(e[4],10));for(c++;c<a.length;){e=a[c].charAt(0);try{var g=decodeURI(a[c].substring(1))}catch(h){throw Error("Illegal escape in patch_fromText: "+g);}if("-"==e)f.diffs.push(new diff_match_patch.Diff(DIFF_DELETE,g));else if("+"==e)f.diffs.push(new diff_match_patch.Diff(DIFF_INSERT,g));else if(" "==e)f.diffs.push(new diff_match_patch.Diff(DIFF_EQUAL,g));else if("@"==e)break;else if(""!==e)throw Error('Invalid patch mode "'+e+'" in: '+g);c++}}return b};
+diff_match_patch.prototype.diff_cleanupSemanticLossless=function(a){function b(a,b){if(!a||!b)return 6;var c=a.charAt(a.length-1),d=b.charAt(0),e=c.match(diff_match_patch.nonAlphaNumericRegex_),f=d.match(diff_match_patch.nonAlphaNumericRegex_),g=e&&c.match(diff_match_patch.whitespaceRegex_),h=f&&d.match(diff_match_patch.whitespaceRegex_);c=g&&c.match(diff_match_patch.linebreakRegex_);d=h&&d.match(diff_match_patch.linebreakRegex_);a=c&&a.match(diff_match_patch.blanklineEndRegex_);b=d&&b.match(diff_match_patch.blanklineStartRegex_);
+return a||b?5:c||d?4:e&&!g&&h?3:g||h?2:e||f?1:0}for(var d=1;d<a.length-1;){if(a[d-1][0]==DIFF_EQUAL&&a[d+1][0]==DIFF_EQUAL){var c=a[d-1][1],e=a[d][1],f=a[d+1][1],g=this.diff_commonSuffix(c,e);if(g){var h=e.substring(e.length-g);c=c.substring(0,c.length-g);e=h+e.substring(0,e.length-g);f=h+f}g=c;h=e;for(var l=f,k=b(c,e)+b(e,f);e.charAt(0)===f.charAt(0);){c+=e.charAt(0);e=e.substring(1)+f.charAt(0);f=f.substring(1);var m=b(c,e)+b(e,f);m>=k&&(k=m,g=c,h=e,l=f)}a[d-1][1]!=g&&(g?a[d-1][1]=g:(a.splice(d-
+1,1),d--),a[d][1]=h,l?a[d+1][1]=l:(a.splice(d+1,1),d--))}d++}};diff_match_patch.nonAlphaNumericRegex_=/[^a-zA-Z0-9]/;diff_match_patch.whitespaceRegex_=/\s/;diff_match_patch.linebreakRegex_=/[\r\n]/;diff_match_patch.blanklineEndRegex_=/\n\r?\n$/;diff_match_patch.blanklineStartRegex_=/^\r?\n\r?\n/;
+diff_match_patch.prototype.diff_cleanupEfficiency=function(a){for(var b=!1,d=[],c=0,e=null,f=0,g=!1,h=!1,l=!1,k=!1;f<a.length;)a[f][0]==DIFF_EQUAL?(a[f][1].length<this.Diff_EditCost&&(l||k)?(d[c++]=f,g=l,h=k,e=a[f][1]):(c=0,e=null),l=k=!1):(a[f][0]==DIFF_DELETE?k=!0:l=!0,e&&(g&&h&&l&&k||e.length<this.Diff_EditCost/2&&3==g+h+l+k)&&(a.splice(d[c-1],0,new diff_match_patch.Diff(DIFF_DELETE,e)),a[d[c-1]+1][0]=DIFF_INSERT,c--,e=null,g&&h?(l=k=!0,c=0):(c--,f=0<c?d[c-1]:-1,l=k=!1),b=!0)),f++;b&&this.diff_cleanupMerge(a)};
+diff_match_patch.prototype.diff_cleanupMerge=function(a){a.push(new diff_match_patch.Diff(DIFF_EQUAL,""));for(var b=0,d=0,c=0,e="",f="",g;b<a.length;)switch(a[b][0]){case DIFF_INSERT:c++;f+=a[b][1];b++;break;case DIFF_DELETE:d++;e+=a[b][1];b++;break;case DIFF_EQUAL:1<d+c?(0!==d&&0!==c&&(g=this.diff_commonPrefix(f,e),0!==g&&(0<b-d-c&&a[b-d-c-1][0]==DIFF_EQUAL?a[b-d-c-1][1]+=f.substring(0,g):(a.splice(0,0,new diff_match_patch.Diff(DIFF_EQUAL,f.substring(0,g))),b++),f=f.substring(g),e=e.substring(g)),
+g=this.diff_commonSuffix(f,e),0!==g&&(a[b][1]=f.substring(f.length-g)+a[b][1],f=f.substring(0,f.length-g),e=e.substring(0,e.length-g))),b-=d+c,a.splice(b,d+c),e.length&&(a.splice(b,0,new diff_match_patch.Diff(DIFF_DELETE,e)),b++),f.length&&(a.splice(b,0,new diff_match_patch.Diff(DIFF_INSERT,f)),b++),b++):0!==b&&a[b-1][0]==DIFF_EQUAL?(a[b-1][1]+=a[b][1],a.splice(b,1)):b++,d=c=0,f=e=""}""===a[a.length-1][1]&&a.pop();d=!1;for(b=1;b<a.length-1;)a[b-1][0]==DIFF_EQUAL&&a[b+1][0]==DIFF_EQUAL&&(a[b][1].substring(a[b][1].length-
+a[b-1][1].length)==a[b-1][1]?(a[b][1]=a[b-1][1]+a[b][1].substring(0,a[b][1].length-a[b-1][1].length),a[b+1][1]=a[b-1][1]+a[b+1][1],a.splice(b-1,1),d=!0):a[b][1].substring(0,a[b+1][1].length)==a[b+1][1]&&(a[b-1][1]+=a[b+1][1],a[b][1]=a[b][1].substring(a[b+1][1].length)+a[b+1][1],a.splice(b+1,1),d=!0)),b++;d&&this.diff_cleanupMerge(a)};
+diff_match_patch.prototype.diff_xIndex=function(a,b){var d=0,c=0,e=0,f=0,g;for(g=0;g<a.length;g++){a[g][0]!==DIFF_INSERT&&(d+=a[g][1].length);a[g][0]!==DIFF_DELETE&&(c+=a[g][1].length);if(d>b)break;e=d;f=c}return a.length!=g&&a[g][0]===DIFF_DELETE?f:f+(b-e)};
+diff_match_patch.prototype.diff_prettyHtml=function(a){for(var b=[],d=/&/g,c=/</g,e=/>/g,f=/\n/g,g=0;g<a.length;g++){var h=a[g][0],l=a[g][1].replace(d,"&amp;").replace(c,"&lt;").replace(e,"&gt;").replace(f,"&para;<br>");switch(h){case DIFF_INSERT:b[g]='<ins style="background:#e6ffe6;">'+l+"</ins>";break;case DIFF_DELETE:b[g]='<del style="background:#ffe6e6;">'+l+"</del>";break;case DIFF_EQUAL:b[g]="<span>"+l+"</span>"}}return b.join("")};
+diff_match_patch.prototype.diff_text1=function(a){for(var b=[],d=0;d<a.length;d++)a[d][0]!==DIFF_INSERT&&(b[d]=a[d][1]);return b.join("")};diff_match_patch.prototype.diff_text2=function(a){for(var b=[],d=0;d<a.length;d++)a[d][0]!==DIFF_DELETE&&(b[d]=a[d][1]);return b.join("")};
+diff_match_patch.prototype.diff_levenshtein=function(a){for(var b=0,d=0,c=0,e=0;e<a.length;e++){var f=a[e][1];switch(a[e][0]){case DIFF_INSERT:d+=f.length;break;case DIFF_DELETE:c+=f.length;break;case DIFF_EQUAL:b+=Math.max(d,c),c=d=0}}return b+=Math.max(d,c)};diff_match_patch.prototype.isHighSurrogate=function(a){a=a.charCodeAt(0);return 55296<=a&&56319>=a};diff_match_patch.prototype.isLowSurrogate=function(a){a=a.charCodeAt(0);return 56320<=a&&57343>=a};
+diff_match_patch.prototype.diff_toDelta=function(a){for(var b=[],d,c=0;c<a.length;c++){var e=a[c],f=e[1][0],g=e[1][e[1].length-1];g&&this.isHighSurrogate(g)&&(e[1]=e[1].slice(0,-1));d&&f&&this.isHighSurrogate(d)&&this.isLowSurrogate(f)&&(e[1]=d+e[1]);d=g;if(0!==e[1].length)switch(a[c][0]){case DIFF_INSERT:b[c]="+"+encodeURI(a[c][1]);break;case DIFF_DELETE:b[c]="-"+a[c][1].length;break;case DIFF_EQUAL:b[c]="="+a[c][1].length}}return b.join("\t").replace(/%20/g," ")};
+diff_match_patch.prototype.diff_fromDelta=function(a,b){var d=[],c=0,e=0;b=b.split(/\t/g);for(var f=0;f<b.length;f++){var g=b[f].substring(1);switch(b[f].charAt(0)){case "+":try{d[c++]=new diff_match_patch.Diff(DIFF_INSERT,decodeURI(g))}catch(l){throw Error("Illegal escape in diff_fromDelta: "+g);}break;case "-":case "=":var h=parseInt(g,10);if(isNaN(h)||0>h)throw Error("Invalid number in diff_fromDelta: "+g);g=a.substring(e,e+=h);"="==b[f].charAt(0)?d[c++]=new diff_match_patch.Diff(DIFF_EQUAL,g):
+d[c++]=new diff_match_patch.Diff(DIFF_DELETE,g);break;default:if(b[f])throw Error("Invalid diff operation in diff_fromDelta: "+b[f]);}}if(e!=a.length)throw Error("Delta length ("+e+") does not equal source text length ("+a.length+").");return d};diff_match_patch.prototype.match_main=function(a,b,d){if(null==a||null==b||null==d)throw Error("Null input. (match_main)");d=Math.max(0,Math.min(d,a.length));return a==b?0:a.length?a.substring(d,d+b.length)==b?d:this.match_bitap_(a,b,d):-1};
+diff_match_patch.prototype.match_bitap_=function(a,b,d){function c(a,c){a/=b.length;c=Math.abs(d-c);return f.Match_Distance?a+c/f.Match_Distance:c?1:a}if(b.length>this.Match_MaxBits)throw Error("Pattern too long for this browser.");var e=this.match_alphabet_(b),f=this,g=this.Match_Threshold,h=a.indexOf(b,d);-1!=h&&(g=Math.min(c(0,h),g),h=a.lastIndexOf(b,d+b.length),-1!=h&&(g=Math.min(c(0,h),g)));var l=1<<b.length-1;h=-1;for(var k,m,p=b.length+a.length,x,w=0;w<b.length;w++){k=0;for(m=p;k<m;)c(w,d+
+m)<=g?k=m:p=m,m=Math.floor((p-k)/2+k);p=m;k=Math.max(1,d-m+1);var t=Math.min(d+m,a.length)+b.length;m=Array(t+2);for(m[t+1]=(1<<w)-1;t>=k;t--){var u=e[a.charAt(t-1)];m[t]=0===w?(m[t+1]<<1|1)&u:(m[t+1]<<1|1)&u|(x[t+1]|x[t])<<1|1|x[t+1];if(m[t]&l&&(u=c(w,t-1),u<=g))if(g=u,h=t-1,h>d)k=Math.max(1,2*d-h);else break}if(c(w+1,d)>g)break;x=m}return h};
+diff_match_patch.prototype.match_alphabet_=function(a){for(var b={},d=0;d<a.length;d++)b[a.charAt(d)]=0;for(d=0;d<a.length;d++)b[a.charAt(d)]|=1<<a.length-d-1;return b};
+diff_match_patch.prototype.patch_addContext_=function(a,b){if(0!=b.length){if(null===a.start2)throw Error("patch not initialized");for(var d=b.substring(a.start2,a.start2+a.length1),c=0;b.indexOf(d)!=b.lastIndexOf(d)&&d.length<this.Match_MaxBits-this.Patch_Margin-this.Patch_Margin;)c+=this.Patch_Margin,d=b.substring(a.start2-c,a.start2+a.length1+c);c+=this.Patch_Margin;(d=b.substring(a.start2-c,a.start2))&&a.diffs.unshift(new diff_match_patch.Diff(DIFF_EQUAL,d));(b=b.substring(a.start2+a.length1,
+a.start2+a.length1+c))&&a.diffs.push(new diff_match_patch.Diff(DIFF_EQUAL,b));a.start1-=d.length;a.start2-=d.length;a.length1+=d.length+b.length;a.length2+=d.length+b.length}};
+diff_match_patch.prototype.patch_make=function(a,b,d){if("string"==typeof a&&"string"==typeof b&&"undefined"==typeof d){var c=a;b=this.diff_main(c,b,!0);2<b.length&&(this.diff_cleanupSemantic(b),this.diff_cleanupEfficiency(b))}else if(a&&"object"==typeof a&&"undefined"==typeof b&&"undefined"==typeof d)b=a,c=this.diff_text1(b);else if("string"==typeof a&&b&&"object"==typeof b&&"undefined"==typeof d)c=a;else if("string"==typeof a&&"string"==typeof b&&d&&"object"==typeof d)c=a,b=d;else throw Error("Unknown call format to patch_make.");
+if(0===b.length)return[];d=[];a=new diff_match_patch.patch_obj;for(var e=0,f=0,g=0,h=c,l=0;l<b.length;l++){var k=b[l][0],m=b[l][1];e||k===DIFF_EQUAL||(a.start1=f,a.start2=g);switch(k){case DIFF_INSERT:a.diffs[e++]=b[l];a.length2+=m.length;c=c.substring(0,g)+m+c.substring(g);break;case DIFF_DELETE:a.length1+=m.length;a.diffs[e++]=b[l];c=c.substring(0,g)+c.substring(g+m.length);break;case DIFF_EQUAL:m.length<=2*this.Patch_Margin&&e&&b.length!=l+1?(a.diffs[e++]=b[l],a.length1+=m.length,a.length2+=m.length):
+m.length>=2*this.Patch_Margin&&e&&(this.patch_addContext_(a,h),d.push(a),a=new diff_match_patch.patch_obj,e=0,h=c,f=g)}k!==DIFF_INSERT&&(f+=m.length);k!==DIFF_DELETE&&(g+=m.length)}e&&(this.patch_addContext_(a,h),d.push(a));return d};
+diff_match_patch.prototype.patch_deepCopy=function(a){for(var b=[],d=0;d<a.length;d++){var c=a[d],e=new diff_match_patch.patch_obj;e.diffs=[];for(var f=0;f<c.diffs.length;f++)e.diffs[f]=new diff_match_patch.Diff(c.diffs[f][0],c.diffs[f][1]);e.start1=c.start1;e.start2=c.start2;e.length1=c.length1;e.length2=c.length2;b[d]=e}return b};
+diff_match_patch.prototype.patch_apply=function(a,b){if(0==a.length)return[b,[]];a=this.patch_deepCopy(a);var d=this.patch_addPadding(a);b=d+b+d;this.patch_splitMax(a);for(var c=0,e=[],f=0;f<a.length;f++){var g=a[f].start2+c,h=this.diff_text1(a[f].diffs),l=-1;if(h.length>this.Match_MaxBits){var k=this.match_main(b,h.substring(0,this.Match_MaxBits),g);-1!=k&&(l=this.match_main(b,h.substring(h.length-this.Match_MaxBits),g+h.length-this.Match_MaxBits),-1==l||k>=l)&&(k=-1)}else k=this.match_main(b,h,
+g);if(-1==k)e[f]=!1,c-=a[f].length2-a[f].length1;else if(e[f]=!0,c=k-g,g=-1==l?b.substring(k,k+h.length):b.substring(k,l+this.Match_MaxBits),h==g)b=b.substring(0,k)+this.diff_text2(a[f].diffs)+b.substring(k+h.length);else if(g=this.diff_main(h,g,!1),h.length>this.Match_MaxBits&&this.diff_levenshtein(g)/h.length>this.Patch_DeleteThreshold)e[f]=!1;else{this.diff_cleanupSemanticLossless(g);h=0;var m;for(l=0;l<a[f].diffs.length;l++){var p=a[f].diffs[l];p[0]!==DIFF_EQUAL&&(m=this.diff_xIndex(g,h));p[0]===
+DIFF_INSERT?b=b.substring(0,k+m)+p[1]+b.substring(k+m):p[0]===DIFF_DELETE&&(b=b.substring(0,k+m)+b.substring(k+this.diff_xIndex(g,h+p[1].length)));p[0]!==DIFF_DELETE&&(h+=p[1].length)}}}b=b.substring(d.length,b.length-d.length);return[b,e]};
+diff_match_patch.prototype.patch_addPadding=function(a){for(var b=this.Patch_Margin,d="",c=1;c<=b;c++)d+=String.fromCharCode(c);for(c=0;c<a.length;c++)a[c].start1+=b,a[c].start2+=b;c=a[0];var e=c.diffs;if(0==e.length||e[0][0]!=DIFF_EQUAL)e.unshift(new diff_match_patch.Diff(DIFF_EQUAL,d)),c.start1-=b,c.start2-=b,c.length1+=b,c.length2+=b;else if(b>e[0][1].length){var f=b-e[0][1].length;e[0][1]=d.substring(e[0][1].length)+e[0][1];c.start1-=f;c.start2-=f;c.length1+=f;c.length2+=f}c=a[a.length-1];e=c.diffs;
+0==e.length||e[e.length-1][0]!=DIFF_EQUAL?(e.push(new diff_match_patch.Diff(DIFF_EQUAL,d)),c.length1+=b,c.length2+=b):b>e[e.length-1][1].length&&(f=b-e[e.length-1][1].length,e[e.length-1][1]+=d.substring(0,f),c.length1+=f,c.length2+=f);return d};
+diff_match_patch.prototype.patch_splitMax=function(a){for(var b=this.Match_MaxBits,d=0;d<a.length;d++)if(!(a[d].length1<=b)){var c=a[d];a.splice(d--,1);for(var e=c.start1,f=c.start2,g="";0!==c.diffs.length;){var h=new diff_match_patch.patch_obj,l=!0;h.start1=e-g.length;h.start2=f-g.length;""!==g&&(h.length1=h.length2=g.length,h.diffs.push(new diff_match_patch.Diff(DIFF_EQUAL,g)));for(;0!==c.diffs.length&&h.length1<b-this.Patch_Margin;){g=c.diffs[0][0];var k=c.diffs[0][1];g===DIFF_INSERT?(h.length2+=
+k.length,f+=k.length,h.diffs.push(c.diffs.shift()),l=!1):g===DIFF_DELETE&&1==h.diffs.length&&h.diffs[0][0]==DIFF_EQUAL&&k.length>2*b?(h.length1+=k.length,e+=k.length,l=!1,h.diffs.push(new diff_match_patch.Diff(g,k)),c.diffs.shift()):(k=k.substring(0,b-h.length1-this.Patch_Margin),h.length1+=k.length,e+=k.length,g===DIFF_EQUAL?(h.length2+=k.length,f+=k.length):l=!1,h.diffs.push(new diff_match_patch.Diff(g,k)),k==c.diffs[0][1]?c.diffs.shift():c.diffs[0][1]=c.diffs[0][1].substring(k.length))}g=this.diff_text2(h.diffs);
+g=g.substring(g.length-this.Patch_Margin);k=this.diff_text1(c.diffs).substring(0,this.Patch_Margin);""!==k&&(h.length1+=k.length,h.length2+=k.length,0!==h.diffs.length&&h.diffs[h.diffs.length-1][0]===DIFF_EQUAL?h.diffs[h.diffs.length-1][1]+=k:h.diffs.push(new diff_match_patch.Diff(DIFF_EQUAL,k)));l||a.splice(++d,0,h)}}};diff_match_patch.prototype.patch_toText=function(a){for(var b=[],d=0;d<a.length;d++)b[d]=a[d];return b.join("")};
+diff_match_patch.prototype.patch_fromText=function(a){var b=[];if(!a)return b;a=a.split("\n");for(var d=0,c=/^@@ -(\d+),?(\d*) \+(\d+),?(\d*) @@$/;d<a.length;){var e=a[d].match(c);if(!e)throw Error("Invalid patch string: "+a[d]);var f=new diff_match_patch.patch_obj;b.push(f);f.start1=parseInt(e[1],10);""===e[2]?(f.start1--,f.length1=1):"0"==e[2]?f.length1=0:(f.start1--,f.length1=parseInt(e[2],10));f.start2=parseInt(e[3],10);""===e[4]?(f.start2--,f.length2=1):"0"==e[4]?f.length2=0:(f.start2--,f.length2=
+parseInt(e[4],10));for(d++;d<a.length;){e=a[d].charAt(0);try{var g=decodeURI(a[d].substring(1))}catch(h){throw Error("Illegal escape in patch_fromText: "+g);}if("-"==e)f.diffs.push(new diff_match_patch.Diff(DIFF_DELETE,g));else if("+"==e)f.diffs.push(new diff_match_patch.Diff(DIFF_INSERT,g));else if(" "==e)f.diffs.push(new diff_match_patch.Diff(DIFF_EQUAL,g));else if("@"==e)break;else if(""!==e)throw Error('Invalid patch mode "'+e+'" in: '+g);d++}}return b};
 diff_match_patch.patch_obj=function(){this.diffs=[];this.start2=this.start1=null;this.length2=this.length1=0};
-diff_match_patch.patch_obj.prototype.toString=function(){for(var a=["@@ -"+(0===this.length1?this.start1+",0":1==this.length1?this.start1+1:this.start1+1+","+this.length1)+" +"+(0===this.length2?this.start2+",0":1==this.length2?this.start2+1:this.start2+1+","+this.length2)+" @@\n"],b,c=0;c<this.diffs.length;c++){switch(this.diffs[c][0]){case DIFF_INSERT:b="+";break;case DIFF_DELETE:b="-";break;case DIFF_EQUAL:b=" "}a[c+1]=b+encodeURI(this.diffs[c][1])+"\n"}return a.join("").replace(/%20/g," ")};
+diff_match_patch.patch_obj.prototype.toString=function(){for(var a=["@@ -"+(0===this.length1?this.start1+",0":1==this.length1?this.start1+1:this.start1+1+","+this.length1)+" +"+(0===this.length2?this.start2+",0":1==this.length2?this.start2+1:this.start2+1+","+this.length2)+" @@\n"],b,d=0;d<this.diffs.length;d++){switch(this.diffs[d][0]){case DIFF_INSERT:b="+";break;case DIFF_DELETE:b="-";break;case DIFF_EQUAL:b=" "}a[d+1]=b+encodeURI(this.diffs[d][1])+"\n"}return a.join("").replace(/%20/g," ")};
 this.diff_match_patch=diff_match_patch;this.DIFF_DELETE=DIFF_DELETE;this.DIFF_INSERT=DIFF_INSERT;this.DIFF_EQUAL=DIFF_EQUAL;

From a5f35ab0549121a9e1e7af8cfbe837281aede325 Mon Sep 17 00:00:00 2001
From: Dennis Snell <dennis.snell@automattic.com>
Date: Thu, 12 Dec 2019 20:36:02 -0700
Subject: [PATCH 13/34] Handle cases where we delete characters

In the previous iteration of this patch we were only properly handling
cases where a new surrogate pair was inserted in between two existing
pairs whose high surrogates all matched.

Unfortunately when swapping characters or performing any edits where we
delete a surrogate pair the patch failed because it only carried the
trailing high surrogate over to the next group instead of distributing
it to any insert _and_ delete groups following an equality group.

In this patch I've updated the JavaScript library to properly distribute
the trailing high surrogate.
---
 javascript/diff_match_patch.js              | 105 ++++++++++----------
 javascript/diff_match_patch_uncompressed.js |  24 +++--
 javascript/tests/diff_match_patch_test.js   |  39 +++++++-
 3 files changed, 109 insertions(+), 59 deletions(-)

diff --git a/javascript/diff_match_patch.js b/javascript/diff_match_patch.js
index 7fce1db..4ba112a 100644
--- a/javascript/diff_match_patch.js
+++ b/javascript/diff_match_patch.js
@@ -1,55 +1,56 @@
 var diff_match_patch=function(){this.Diff_Timeout=1;this.Diff_EditCost=4;this.Match_Threshold=.5;this.Match_Distance=1E3;this.Patch_DeleteThreshold=.5;this.Patch_Margin=4;this.Match_MaxBits=32},DIFF_DELETE=-1,DIFF_INSERT=1,DIFF_EQUAL=0;diff_match_patch.Diff=function(a,b){this[0]=a;this[1]=b};diff_match_patch.Diff.prototype.length=2;diff_match_patch.Diff.prototype.toString=function(){return this[0]+","+this[1]};
-diff_match_patch.prototype.diff_main=function(a,b,d,c){"undefined"==typeof c&&(c=0>=this.Diff_Timeout?Number.MAX_VALUE:(new Date).getTime()+1E3*this.Diff_Timeout);if(null==a||null==b)throw Error("Null input. (diff_main)");if(a==b)return a?[new diff_match_patch.Diff(DIFF_EQUAL,a)]:[];"undefined"==typeof d&&(d=!0);var e=d,f=this.diff_commonPrefix(a,b);d=a.substring(0,f);a=a.substring(f);b=b.substring(f);f=this.diff_commonSuffix(a,b);var g=a.substring(a.length-f);a=a.substring(0,a.length-f);b=b.substring(0,
-b.length-f);a=this.diff_compute_(a,b,e,c);d&&a.unshift(new diff_match_patch.Diff(DIFF_EQUAL,d));g&&a.push(new diff_match_patch.Diff(DIFF_EQUAL,g));this.diff_cleanupMerge(a);return a};
-diff_match_patch.prototype.diff_compute_=function(a,b,d,c){if(!a)return[new diff_match_patch.Diff(DIFF_INSERT,b)];if(!b)return[new diff_match_patch.Diff(DIFF_DELETE,a)];var e=a.length>b.length?a:b,f=a.length>b.length?b:a,g=e.indexOf(f);return-1!=g?(d=[new diff_match_patch.Diff(DIFF_INSERT,e.substring(0,g)),new diff_match_patch.Diff(DIFF_EQUAL,f),new diff_match_patch.Diff(DIFF_INSERT,e.substring(g+f.length))],a.length>b.length&&(d[0][0]=d[2][0]=DIFF_DELETE),d):1==f.length?[new diff_match_patch.Diff(DIFF_DELETE,
-a),new diff_match_patch.Diff(DIFF_INSERT,b)]:(e=this.diff_halfMatch_(a,b))?(b=e[1],f=e[3],a=e[4],e=this.diff_main(e[0],e[2],d,c),d=this.diff_main(b,f,d,c),e.concat([new diff_match_patch.Diff(DIFF_EQUAL,a)],d)):d&&100<a.length&&100<b.length?this.diff_lineMode_(a,b,c):this.diff_bisect_(a,b,c)};
-diff_match_patch.prototype.diff_lineMode_=function(a,b,d){var c=this.diff_linesToChars_(a,b);a=c.chars1;b=c.chars2;c=c.lineArray;a=this.diff_main(a,b,!1,d);this.diff_charsToLines_(a,c);this.diff_cleanupSemantic(a);a.push(new diff_match_patch.Diff(DIFF_EQUAL,""));for(var e=c=b=0,f="",g="";b<a.length;){switch(a[b][0]){case DIFF_INSERT:e++;g+=a[b][1];break;case DIFF_DELETE:c++;f+=a[b][1];break;case DIFF_EQUAL:if(1<=c&&1<=e){a.splice(b-c-e,c+e);b=b-c-e;c=this.diff_main(f,g,!1,d);for(e=c.length-1;0<=e;e--)a.splice(b,
-0,c[e]);b+=c.length}c=e=0;g=f=""}b++}a.pop();return a};
-diff_match_patch.prototype.diff_bisect_=function(a,b,d){for(var c=a.length,e=b.length,f=Math.ceil((c+e)/2),g=2*f,h=Array(g),l=Array(g),k=0;k<g;k++)h[k]=-1,l[k]=-1;h[f+1]=0;l[f+1]=0;k=c-e;for(var m=0!=k%2,p=0,x=0,w=0,t=0,u=0;u<f&&!((new Date).getTime()>d);u++){for(var r=-u+p;r<=u-x;r+=2){var n=f+r;var q=r==-u||r!=u&&h[n-1]<h[n+1]?h[n+1]:h[n-1]+1;for(var y=q-r;q<c&&y<e&&a.charAt(q)==b.charAt(y);)q++,y++;h[n]=q;if(q>c)x+=2;else if(y>e)p+=2;else if(m&&(n=f+k-r,0<=n&&n<g&&-1!=l[n])){var v=c-l[n];if(q>=
-v)return this.diff_bisectSplit_(a,b,q,y,d)}}for(r=-u+w;r<=u-t;r+=2){n=f+r;v=r==-u||r!=u&&l[n-1]<l[n+1]?l[n+1]:l[n-1]+1;for(q=v-r;v<c&&q<e&&a.charAt(c-v-1)==b.charAt(e-q-1);)v++,q++;l[n]=v;if(v>c)t+=2;else if(q>e)w+=2;else if(!m&&(n=f+k-r,0<=n&&n<g&&-1!=h[n]&&(q=h[n],y=f+q-n,v=c-v,q>=v)))return this.diff_bisectSplit_(a,b,q,y,d)}}return[new diff_match_patch.Diff(DIFF_DELETE,a),new diff_match_patch.Diff(DIFF_INSERT,b)]};
-diff_match_patch.prototype.diff_bisectSplit_=function(a,b,d,c,e){var f=a.substring(0,d),g=b.substring(0,c);a=a.substring(d);b=b.substring(c);f=this.diff_main(f,g,!1,e);e=this.diff_main(a,b,!1,e);return f.concat(e)};
-diff_match_patch.prototype.diff_linesToChars_=function(a,b){function d(a){for(var b="",d=0,g=-1,m=c.length;g<a.length-1;){g=a.indexOf("\n",d);-1==g&&(g=a.length-1);var p=a.substring(d,g+1);(e.hasOwnProperty?e.hasOwnProperty(p):void 0!==e[p])?b+=String.fromCharCode(e[p]):(m==f&&(p=a.substring(d),g=a.length),b+=String.fromCharCode(m),e[p]=m,c[m++]=p);d=g+1}return b}var c=[],e={};c[0]="";var f=4E4;a=d(a);f=65535;b=d(b);return{chars1:a,chars2:b,lineArray:c}};
-diff_match_patch.prototype.diff_charsToLines_=function(a,b){for(var d=0;d<a.length;d++){for(var c=a[d][1],e=[],f=0;f<c.length;f++)e[f]=b[c.charCodeAt(f)];a[d][1]=e.join("")}};diff_match_patch.prototype.diff_commonPrefix=function(a,b){if(!a||!b||a.charAt(0)!=b.charAt(0))return 0;for(var d=0,c=Math.min(a.length,b.length),e=c,f=0;d<e;)a.substring(f,e)==b.substring(f,e)?f=d=e:c=e,e=Math.floor((c-d)/2+d);return e};
-diff_match_patch.prototype.diff_commonSuffix=function(a,b){if(!a||!b||a.charAt(a.length-1)!=b.charAt(b.length-1))return 0;for(var d=0,c=Math.min(a.length,b.length),e=c,f=0;d<e;)a.substring(a.length-e,a.length-f)==b.substring(b.length-e,b.length-f)?f=d=e:c=e,e=Math.floor((c-d)/2+d);return e};
-diff_match_patch.prototype.diff_commonOverlap_=function(a,b){var d=a.length,c=b.length;if(0==d||0==c)return 0;d>c?a=a.substring(d-c):d<c&&(b=b.substring(0,d));d=Math.min(d,c);if(a==b)return d;c=0;for(var e=1;;){var f=a.substring(d-e);f=b.indexOf(f);if(-1==f)return c;e+=f;if(0==f||a.substring(d-e)==b.substring(0,e))c=e,e++}};
-diff_match_patch.prototype.diff_halfMatch_=function(a,b){function d(a,b,c){for(var d=a.substring(c,c+Math.floor(a.length/4)),e=-1,g="",h,k,l,r;-1!=(e=b.indexOf(d,e+1));){var n=f.diff_commonPrefix(a.substring(c),b.substring(e)),q=f.diff_commonSuffix(a.substring(0,c),b.substring(0,e));g.length<q+n&&(g=b.substring(e-q,e)+b.substring(e,e+n),h=a.substring(0,c-q),k=a.substring(c+n),l=b.substring(0,e-q),r=b.substring(e+n))}return 2*g.length>=a.length?[h,k,l,r,g]:null}if(0>=this.Diff_Timeout)return null;
-var c=a.length>b.length?a:b,e=a.length>b.length?b:a;if(4>c.length||2*e.length<c.length)return null;var f=this,g=d(c,e,Math.ceil(c.length/4));c=d(c,e,Math.ceil(c.length/2));if(g||c)g=c?g?g[4].length>c[4].length?g:c:c:g;else return null;a.length>b.length?(a=g[0],b=g[1],c=g[2],e=g[3]):(c=g[0],e=g[1],a=g[2],b=g[3]);return[a,b,c,e,g[4]]};
-diff_match_patch.prototype.diff_cleanupSemantic=function(a){for(var b=!1,d=[],c=0,e=null,f=0,g=0,h=0,l=0,k=0;f<a.length;)a[f][0]==DIFF_EQUAL?(d[c++]=f,g=l,h=k,k=l=0,e=a[f][1]):(a[f][0]==DIFF_INSERT?l+=a[f][1].length:k+=a[f][1].length,e&&e.length<=Math.max(g,h)&&e.length<=Math.max(l,k)&&(a.splice(d[c-1],0,new diff_match_patch.Diff(DIFF_DELETE,e)),a[d[c-1]+1][0]=DIFF_INSERT,c--,c--,f=0<c?d[c-1]:-1,k=l=h=g=0,e=null,b=!0)),f++;b&&this.diff_cleanupMerge(a);this.diff_cleanupSemanticLossless(a);for(f=1;f<
-a.length;){if(a[f-1][0]==DIFF_DELETE&&a[f][0]==DIFF_INSERT){b=a[f-1][1];d=a[f][1];c=this.diff_commonOverlap_(b,d);e=this.diff_commonOverlap_(d,b);if(c>=e){if(c>=b.length/2||c>=d.length/2)a.splice(f,0,new diff_match_patch.Diff(DIFF_EQUAL,d.substring(0,c))),a[f-1][1]=b.substring(0,b.length-c),a[f+1][1]=d.substring(c),f++}else if(e>=b.length/2||e>=d.length/2)a.splice(f,0,new diff_match_patch.Diff(DIFF_EQUAL,b.substring(0,e))),a[f-1][0]=DIFF_INSERT,a[f-1][1]=d.substring(0,d.length-e),a[f+1][0]=DIFF_DELETE,
+diff_match_patch.prototype.diff_main=function(a,b,c,d){"undefined"==typeof d&&(d=0>=this.Diff_Timeout?Number.MAX_VALUE:(new Date).getTime()+1E3*this.Diff_Timeout);if(null==a||null==b)throw Error("Null input. (diff_main)");if(a==b)return a?[new diff_match_patch.Diff(DIFF_EQUAL,a)]:[];"undefined"==typeof c&&(c=!0);var e=c,f=this.diff_commonPrefix(a,b);c=a.substring(0,f);a=a.substring(f);b=b.substring(f);f=this.diff_commonSuffix(a,b);var g=a.substring(a.length-f);a=a.substring(0,a.length-f);b=b.substring(0,
+b.length-f);a=this.diff_compute_(a,b,e,d);c&&a.unshift(new diff_match_patch.Diff(DIFF_EQUAL,c));g&&a.push(new diff_match_patch.Diff(DIFF_EQUAL,g));this.diff_cleanupMerge(a);return a};
+diff_match_patch.prototype.diff_compute_=function(a,b,c,d){if(!a)return[new diff_match_patch.Diff(DIFF_INSERT,b)];if(!b)return[new diff_match_patch.Diff(DIFF_DELETE,a)];var e=a.length>b.length?a:b,f=a.length>b.length?b:a,g=e.indexOf(f);return-1!=g?(c=[new diff_match_patch.Diff(DIFF_INSERT,e.substring(0,g)),new diff_match_patch.Diff(DIFF_EQUAL,f),new diff_match_patch.Diff(DIFF_INSERT,e.substring(g+f.length))],a.length>b.length&&(c[0][0]=c[2][0]=DIFF_DELETE),c):1==f.length?[new diff_match_patch.Diff(DIFF_DELETE,
+a),new diff_match_patch.Diff(DIFF_INSERT,b)]:(e=this.diff_halfMatch_(a,b))?(b=e[1],f=e[3],a=e[4],e=this.diff_main(e[0],e[2],c,d),c=this.diff_main(b,f,c,d),e.concat([new diff_match_patch.Diff(DIFF_EQUAL,a)],c)):c&&100<a.length&&100<b.length?this.diff_lineMode_(a,b,d):this.diff_bisect_(a,b,d)};
+diff_match_patch.prototype.diff_lineMode_=function(a,b,c){var d=this.diff_linesToChars_(a,b);a=d.chars1;b=d.chars2;d=d.lineArray;a=this.diff_main(a,b,!1,c);this.diff_charsToLines_(a,d);this.diff_cleanupSemantic(a);a.push(new diff_match_patch.Diff(DIFF_EQUAL,""));for(var e=d=b=0,f="",g="";b<a.length;){switch(a[b][0]){case DIFF_INSERT:e++;g+=a[b][1];break;case DIFF_DELETE:d++;f+=a[b][1];break;case DIFF_EQUAL:if(1<=d&&1<=e){a.splice(b-d-e,d+e);b=b-d-e;d=this.diff_main(f,g,!1,c);for(e=d.length-1;0<=e;e--)a.splice(b,
+0,d[e]);b+=d.length}d=e=0;g=f=""}b++}a.pop();return a};
+diff_match_patch.prototype.diff_bisect_=function(a,b,c){for(var d=a.length,e=b.length,f=Math.ceil((d+e)/2),g=2*f,h=Array(g),l=Array(g),k=0;k<g;k++)h[k]=-1,l[k]=-1;h[f+1]=0;l[f+1]=0;k=d-e;for(var m=0!=k%2,p=0,x=0,w=0,q=0,t=0;t<f&&!((new Date).getTime()>c);t++){for(var v=-t+p;v<=t-x;v+=2){var n=f+v;var r=v==-t||v!=t&&h[n-1]<h[n+1]?h[n+1]:h[n-1]+1;for(var y=r-v;r<d&&y<e&&a.charAt(r)==b.charAt(y);)r++,y++;h[n]=r;if(r>d)x+=2;else if(y>e)p+=2;else if(m&&(n=f+k-v,0<=n&&n<g&&-1!=l[n])){var u=d-l[n];if(r>=
+u)return this.diff_bisectSplit_(a,b,r,y,c)}}for(v=-t+w;v<=t-q;v+=2){n=f+v;u=v==-t||v!=t&&l[n-1]<l[n+1]?l[n+1]:l[n-1]+1;for(r=u-v;u<d&&r<e&&a.charAt(d-u-1)==b.charAt(e-r-1);)u++,r++;l[n]=u;if(u>d)q+=2;else if(r>e)w+=2;else if(!m&&(n=f+k-v,0<=n&&n<g&&-1!=h[n]&&(r=h[n],y=f+r-n,u=d-u,r>=u)))return this.diff_bisectSplit_(a,b,r,y,c)}}return[new diff_match_patch.Diff(DIFF_DELETE,a),new diff_match_patch.Diff(DIFF_INSERT,b)]};
+diff_match_patch.prototype.diff_bisectSplit_=function(a,b,c,d,e){var f=a.substring(0,c),g=b.substring(0,d);a=a.substring(c);b=b.substring(d);f=this.diff_main(f,g,!1,e);e=this.diff_main(a,b,!1,e);return f.concat(e)};
+diff_match_patch.prototype.diff_linesToChars_=function(a,b){function c(a){for(var b="",c=0,g=-1,h=d.length;g<a.length-1;){g=a.indexOf("\n",c);-1==g&&(g=a.length-1);var l=a.substring(c,g+1);(e.hasOwnProperty?e.hasOwnProperty(l):void 0!==e[l])?b+=String.fromCharCode(e[l]):(h==f&&(l=a.substring(c),g=a.length),b+=String.fromCharCode(h),e[l]=h,d[h++]=l);c=g+1}return b}var d=[],e={};d[0]="";var f=4E4,g=c(a);f=65535;var h=c(b);return{chars1:g,chars2:h,lineArray:d}};
+diff_match_patch.prototype.diff_charsToLines_=function(a,b){for(var c=0;c<a.length;c++){for(var d=a[c][1],e=[],f=0;f<d.length;f++)e[f]=b[d.charCodeAt(f)];a[c][1]=e.join("")}};diff_match_patch.prototype.diff_commonPrefix=function(a,b){if(!a||!b||a.charAt(0)!=b.charAt(0))return 0;for(var c=0,d=Math.min(a.length,b.length),e=d,f=0;c<e;)a.substring(f,e)==b.substring(f,e)?f=c=e:d=e,e=Math.floor((d-c)/2+c);return e};
+diff_match_patch.prototype.diff_commonSuffix=function(a,b){if(!a||!b||a.charAt(a.length-1)!=b.charAt(b.length-1))return 0;for(var c=0,d=Math.min(a.length,b.length),e=d,f=0;c<e;)a.substring(a.length-e,a.length-f)==b.substring(b.length-e,b.length-f)?f=c=e:d=e,e=Math.floor((d-c)/2+c);return e};
+diff_match_patch.prototype.diff_commonOverlap_=function(a,b){var c=a.length,d=b.length;if(0==c||0==d)return 0;c>d?a=a.substring(c-d):c<d&&(b=b.substring(0,c));c=Math.min(c,d);if(a==b)return c;d=0;for(var e=1;;){var f=a.substring(c-e);f=b.indexOf(f);if(-1==f)return d;e+=f;if(0==f||a.substring(c-e)==b.substring(0,e))d=e,e++}};
+diff_match_patch.prototype.diff_halfMatch_=function(a,b){function c(a,b,c){for(var d=a.substring(c,c+Math.floor(a.length/4)),e=-1,g="",h,k,l,m;-1!=(e=b.indexOf(d,e+1));){var p=f.diff_commonPrefix(a.substring(c),b.substring(e)),u=f.diff_commonSuffix(a.substring(0,c),b.substring(0,e));g.length<u+p&&(g=b.substring(e-u,e)+b.substring(e,e+p),h=a.substring(0,c-u),k=a.substring(c+p),l=b.substring(0,e-u),m=b.substring(e+p))}return 2*g.length>=a.length?[h,k,l,m,g]:null}if(0>=this.Diff_Timeout)return null;
+var d=a.length>b.length?a:b,e=a.length>b.length?b:a;if(4>d.length||2*e.length<d.length)return null;var f=this,g=c(d,e,Math.ceil(d.length/4));d=c(d,e,Math.ceil(d.length/2));if(g||d)g=d?g?g[4].length>d[4].length?g:d:d:g;else return null;if(a.length>b.length){d=g[0];e=g[1];var h=g[2];var l=g[3]}else h=g[0],l=g[1],d=g[2],e=g[3];return[d,e,h,l,g[4]]};
+diff_match_patch.prototype.diff_cleanupSemantic=function(a){for(var b=!1,c=[],d=0,e=null,f=0,g=0,h=0,l=0,k=0;f<a.length;)a[f][0]==DIFF_EQUAL?(c[d++]=f,g=l,h=k,k=l=0,e=a[f][1]):(a[f][0]==DIFF_INSERT?l+=a[f][1].length:k+=a[f][1].length,e&&e.length<=Math.max(g,h)&&e.length<=Math.max(l,k)&&(a.splice(c[d-1],0,new diff_match_patch.Diff(DIFF_DELETE,e)),a[c[d-1]+1][0]=DIFF_INSERT,d--,d--,f=0<d?c[d-1]:-1,k=l=h=g=0,e=null,b=!0)),f++;b&&this.diff_cleanupMerge(a);this.diff_cleanupSemanticLossless(a);for(f=1;f<
+a.length;){if(a[f-1][0]==DIFF_DELETE&&a[f][0]==DIFF_INSERT){b=a[f-1][1];c=a[f][1];d=this.diff_commonOverlap_(b,c);e=this.diff_commonOverlap_(c,b);if(d>=e){if(d>=b.length/2||d>=c.length/2)a.splice(f,0,new diff_match_patch.Diff(DIFF_EQUAL,c.substring(0,d))),a[f-1][1]=b.substring(0,b.length-d),a[f+1][1]=c.substring(d),f++}else if(e>=b.length/2||e>=c.length/2)a.splice(f,0,new diff_match_patch.Diff(DIFF_EQUAL,b.substring(0,e))),a[f-1][0]=DIFF_INSERT,a[f-1][1]=c.substring(0,c.length-e),a[f+1][0]=DIFF_DELETE,
 a[f+1][1]=b.substring(e),f++;f++}f++}};
-diff_match_patch.prototype.diff_cleanupSemanticLossless=function(a){function b(a,b){if(!a||!b)return 6;var c=a.charAt(a.length-1),d=b.charAt(0),e=c.match(diff_match_patch.nonAlphaNumericRegex_),f=d.match(diff_match_patch.nonAlphaNumericRegex_),g=e&&c.match(diff_match_patch.whitespaceRegex_),h=f&&d.match(diff_match_patch.whitespaceRegex_);c=g&&c.match(diff_match_patch.linebreakRegex_);d=h&&d.match(diff_match_patch.linebreakRegex_);a=c&&a.match(diff_match_patch.blanklineEndRegex_);b=d&&b.match(diff_match_patch.blanklineStartRegex_);
-return a||b?5:c||d?4:e&&!g&&h?3:g||h?2:e||f?1:0}for(var d=1;d<a.length-1;){if(a[d-1][0]==DIFF_EQUAL&&a[d+1][0]==DIFF_EQUAL){var c=a[d-1][1],e=a[d][1],f=a[d+1][1],g=this.diff_commonSuffix(c,e);if(g){var h=e.substring(e.length-g);c=c.substring(0,c.length-g);e=h+e.substring(0,e.length-g);f=h+f}g=c;h=e;for(var l=f,k=b(c,e)+b(e,f);e.charAt(0)===f.charAt(0);){c+=e.charAt(0);e=e.substring(1)+f.charAt(0);f=f.substring(1);var m=b(c,e)+b(e,f);m>=k&&(k=m,g=c,h=e,l=f)}a[d-1][1]!=g&&(g?a[d-1][1]=g:(a.splice(d-
-1,1),d--),a[d][1]=h,l?a[d+1][1]=l:(a.splice(d+1,1),d--))}d++}};diff_match_patch.nonAlphaNumericRegex_=/[^a-zA-Z0-9]/;diff_match_patch.whitespaceRegex_=/\s/;diff_match_patch.linebreakRegex_=/[\r\n]/;diff_match_patch.blanklineEndRegex_=/\n\r?\n$/;diff_match_patch.blanklineStartRegex_=/^\r?\n\r?\n/;
-diff_match_patch.prototype.diff_cleanupEfficiency=function(a){for(var b=!1,d=[],c=0,e=null,f=0,g=!1,h=!1,l=!1,k=!1;f<a.length;)a[f][0]==DIFF_EQUAL?(a[f][1].length<this.Diff_EditCost&&(l||k)?(d[c++]=f,g=l,h=k,e=a[f][1]):(c=0,e=null),l=k=!1):(a[f][0]==DIFF_DELETE?k=!0:l=!0,e&&(g&&h&&l&&k||e.length<this.Diff_EditCost/2&&3==g+h+l+k)&&(a.splice(d[c-1],0,new diff_match_patch.Diff(DIFF_DELETE,e)),a[d[c-1]+1][0]=DIFF_INSERT,c--,e=null,g&&h?(l=k=!0,c=0):(c--,f=0<c?d[c-1]:-1,l=k=!1),b=!0)),f++;b&&this.diff_cleanupMerge(a)};
-diff_match_patch.prototype.diff_cleanupMerge=function(a){a.push(new diff_match_patch.Diff(DIFF_EQUAL,""));for(var b=0,d=0,c=0,e="",f="",g;b<a.length;)switch(a[b][0]){case DIFF_INSERT:c++;f+=a[b][1];b++;break;case DIFF_DELETE:d++;e+=a[b][1];b++;break;case DIFF_EQUAL:1<d+c?(0!==d&&0!==c&&(g=this.diff_commonPrefix(f,e),0!==g&&(0<b-d-c&&a[b-d-c-1][0]==DIFF_EQUAL?a[b-d-c-1][1]+=f.substring(0,g):(a.splice(0,0,new diff_match_patch.Diff(DIFF_EQUAL,f.substring(0,g))),b++),f=f.substring(g),e=e.substring(g)),
-g=this.diff_commonSuffix(f,e),0!==g&&(a[b][1]=f.substring(f.length-g)+a[b][1],f=f.substring(0,f.length-g),e=e.substring(0,e.length-g))),b-=d+c,a.splice(b,d+c),e.length&&(a.splice(b,0,new diff_match_patch.Diff(DIFF_DELETE,e)),b++),f.length&&(a.splice(b,0,new diff_match_patch.Diff(DIFF_INSERT,f)),b++),b++):0!==b&&a[b-1][0]==DIFF_EQUAL?(a[b-1][1]+=a[b][1],a.splice(b,1)):b++,d=c=0,f=e=""}""===a[a.length-1][1]&&a.pop();d=!1;for(b=1;b<a.length-1;)a[b-1][0]==DIFF_EQUAL&&a[b+1][0]==DIFF_EQUAL&&(a[b][1].substring(a[b][1].length-
-a[b-1][1].length)==a[b-1][1]?(a[b][1]=a[b-1][1]+a[b][1].substring(0,a[b][1].length-a[b-1][1].length),a[b+1][1]=a[b-1][1]+a[b+1][1],a.splice(b-1,1),d=!0):a[b][1].substring(0,a[b+1][1].length)==a[b+1][1]&&(a[b-1][1]+=a[b+1][1],a[b][1]=a[b][1].substring(a[b+1][1].length)+a[b+1][1],a.splice(b+1,1),d=!0)),b++;d&&this.diff_cleanupMerge(a)};
-diff_match_patch.prototype.diff_xIndex=function(a,b){var d=0,c=0,e=0,f=0,g;for(g=0;g<a.length;g++){a[g][0]!==DIFF_INSERT&&(d+=a[g][1].length);a[g][0]!==DIFF_DELETE&&(c+=a[g][1].length);if(d>b)break;e=d;f=c}return a.length!=g&&a[g][0]===DIFF_DELETE?f:f+(b-e)};
-diff_match_patch.prototype.diff_prettyHtml=function(a){for(var b=[],d=/&/g,c=/</g,e=/>/g,f=/\n/g,g=0;g<a.length;g++){var h=a[g][0],l=a[g][1].replace(d,"&amp;").replace(c,"&lt;").replace(e,"&gt;").replace(f,"&para;<br>");switch(h){case DIFF_INSERT:b[g]='<ins style="background:#e6ffe6;">'+l+"</ins>";break;case DIFF_DELETE:b[g]='<del style="background:#ffe6e6;">'+l+"</del>";break;case DIFF_EQUAL:b[g]="<span>"+l+"</span>"}}return b.join("")};
-diff_match_patch.prototype.diff_text1=function(a){for(var b=[],d=0;d<a.length;d++)a[d][0]!==DIFF_INSERT&&(b[d]=a[d][1]);return b.join("")};diff_match_patch.prototype.diff_text2=function(a){for(var b=[],d=0;d<a.length;d++)a[d][0]!==DIFF_DELETE&&(b[d]=a[d][1]);return b.join("")};
-diff_match_patch.prototype.diff_levenshtein=function(a){for(var b=0,d=0,c=0,e=0;e<a.length;e++){var f=a[e][1];switch(a[e][0]){case DIFF_INSERT:d+=f.length;break;case DIFF_DELETE:c+=f.length;break;case DIFF_EQUAL:b+=Math.max(d,c),c=d=0}}return b+=Math.max(d,c)};diff_match_patch.prototype.isHighSurrogate=function(a){a=a.charCodeAt(0);return 55296<=a&&56319>=a};diff_match_patch.prototype.isLowSurrogate=function(a){a=a.charCodeAt(0);return 56320<=a&&57343>=a};
-diff_match_patch.prototype.diff_toDelta=function(a){for(var b=[],d,c=0;c<a.length;c++){var e=a[c],f=e[1][0],g=e[1][e[1].length-1];g&&this.isHighSurrogate(g)&&(e[1]=e[1].slice(0,-1));d&&f&&this.isHighSurrogate(d)&&this.isLowSurrogate(f)&&(e[1]=d+e[1]);d=g;if(0!==e[1].length)switch(a[c][0]){case DIFF_INSERT:b[c]="+"+encodeURI(a[c][1]);break;case DIFF_DELETE:b[c]="-"+a[c][1].length;break;case DIFF_EQUAL:b[c]="="+a[c][1].length}}return b.join("\t").replace(/%20/g," ")};
-diff_match_patch.prototype.diff_fromDelta=function(a,b){var d=[],c=0,e=0;b=b.split(/\t/g);for(var f=0;f<b.length;f++){var g=b[f].substring(1);switch(b[f].charAt(0)){case "+":try{d[c++]=new diff_match_patch.Diff(DIFF_INSERT,decodeURI(g))}catch(l){throw Error("Illegal escape in diff_fromDelta: "+g);}break;case "-":case "=":var h=parseInt(g,10);if(isNaN(h)||0>h)throw Error("Invalid number in diff_fromDelta: "+g);g=a.substring(e,e+=h);"="==b[f].charAt(0)?d[c++]=new diff_match_patch.Diff(DIFF_EQUAL,g):
-d[c++]=new diff_match_patch.Diff(DIFF_DELETE,g);break;default:if(b[f])throw Error("Invalid diff operation in diff_fromDelta: "+b[f]);}}if(e!=a.length)throw Error("Delta length ("+e+") does not equal source text length ("+a.length+").");return d};diff_match_patch.prototype.match_main=function(a,b,d){if(null==a||null==b||null==d)throw Error("Null input. (match_main)");d=Math.max(0,Math.min(d,a.length));return a==b?0:a.length?a.substring(d,d+b.length)==b?d:this.match_bitap_(a,b,d):-1};
-diff_match_patch.prototype.match_bitap_=function(a,b,d){function c(a,c){a/=b.length;c=Math.abs(d-c);return f.Match_Distance?a+c/f.Match_Distance:c?1:a}if(b.length>this.Match_MaxBits)throw Error("Pattern too long for this browser.");var e=this.match_alphabet_(b),f=this,g=this.Match_Threshold,h=a.indexOf(b,d);-1!=h&&(g=Math.min(c(0,h),g),h=a.lastIndexOf(b,d+b.length),-1!=h&&(g=Math.min(c(0,h),g)));var l=1<<b.length-1;h=-1;for(var k,m,p=b.length+a.length,x,w=0;w<b.length;w++){k=0;for(m=p;k<m;)c(w,d+
-m)<=g?k=m:p=m,m=Math.floor((p-k)/2+k);p=m;k=Math.max(1,d-m+1);var t=Math.min(d+m,a.length)+b.length;m=Array(t+2);for(m[t+1]=(1<<w)-1;t>=k;t--){var u=e[a.charAt(t-1)];m[t]=0===w?(m[t+1]<<1|1)&u:(m[t+1]<<1|1)&u|(x[t+1]|x[t])<<1|1|x[t+1];if(m[t]&l&&(u=c(w,t-1),u<=g))if(g=u,h=t-1,h>d)k=Math.max(1,2*d-h);else break}if(c(w+1,d)>g)break;x=m}return h};
-diff_match_patch.prototype.match_alphabet_=function(a){for(var b={},d=0;d<a.length;d++)b[a.charAt(d)]=0;for(d=0;d<a.length;d++)b[a.charAt(d)]|=1<<a.length-d-1;return b};
-diff_match_patch.prototype.patch_addContext_=function(a,b){if(0!=b.length){if(null===a.start2)throw Error("patch not initialized");for(var d=b.substring(a.start2,a.start2+a.length1),c=0;b.indexOf(d)!=b.lastIndexOf(d)&&d.length<this.Match_MaxBits-this.Patch_Margin-this.Patch_Margin;)c+=this.Patch_Margin,d=b.substring(a.start2-c,a.start2+a.length1+c);c+=this.Patch_Margin;(d=b.substring(a.start2-c,a.start2))&&a.diffs.unshift(new diff_match_patch.Diff(DIFF_EQUAL,d));(b=b.substring(a.start2+a.length1,
-a.start2+a.length1+c))&&a.diffs.push(new diff_match_patch.Diff(DIFF_EQUAL,b));a.start1-=d.length;a.start2-=d.length;a.length1+=d.length+b.length;a.length2+=d.length+b.length}};
-diff_match_patch.prototype.patch_make=function(a,b,d){if("string"==typeof a&&"string"==typeof b&&"undefined"==typeof d){var c=a;b=this.diff_main(c,b,!0);2<b.length&&(this.diff_cleanupSemantic(b),this.diff_cleanupEfficiency(b))}else if(a&&"object"==typeof a&&"undefined"==typeof b&&"undefined"==typeof d)b=a,c=this.diff_text1(b);else if("string"==typeof a&&b&&"object"==typeof b&&"undefined"==typeof d)c=a;else if("string"==typeof a&&"string"==typeof b&&d&&"object"==typeof d)c=a,b=d;else throw Error("Unknown call format to patch_make.");
-if(0===b.length)return[];d=[];a=new diff_match_patch.patch_obj;for(var e=0,f=0,g=0,h=c,l=0;l<b.length;l++){var k=b[l][0],m=b[l][1];e||k===DIFF_EQUAL||(a.start1=f,a.start2=g);switch(k){case DIFF_INSERT:a.diffs[e++]=b[l];a.length2+=m.length;c=c.substring(0,g)+m+c.substring(g);break;case DIFF_DELETE:a.length1+=m.length;a.diffs[e++]=b[l];c=c.substring(0,g)+c.substring(g+m.length);break;case DIFF_EQUAL:m.length<=2*this.Patch_Margin&&e&&b.length!=l+1?(a.diffs[e++]=b[l],a.length1+=m.length,a.length2+=m.length):
-m.length>=2*this.Patch_Margin&&e&&(this.patch_addContext_(a,h),d.push(a),a=new diff_match_patch.patch_obj,e=0,h=c,f=g)}k!==DIFF_INSERT&&(f+=m.length);k!==DIFF_DELETE&&(g+=m.length)}e&&(this.patch_addContext_(a,h),d.push(a));return d};
-diff_match_patch.prototype.patch_deepCopy=function(a){for(var b=[],d=0;d<a.length;d++){var c=a[d],e=new diff_match_patch.patch_obj;e.diffs=[];for(var f=0;f<c.diffs.length;f++)e.diffs[f]=new diff_match_patch.Diff(c.diffs[f][0],c.diffs[f][1]);e.start1=c.start1;e.start2=c.start2;e.length1=c.length1;e.length2=c.length2;b[d]=e}return b};
-diff_match_patch.prototype.patch_apply=function(a,b){if(0==a.length)return[b,[]];a=this.patch_deepCopy(a);var d=this.patch_addPadding(a);b=d+b+d;this.patch_splitMax(a);for(var c=0,e=[],f=0;f<a.length;f++){var g=a[f].start2+c,h=this.diff_text1(a[f].diffs),l=-1;if(h.length>this.Match_MaxBits){var k=this.match_main(b,h.substring(0,this.Match_MaxBits),g);-1!=k&&(l=this.match_main(b,h.substring(h.length-this.Match_MaxBits),g+h.length-this.Match_MaxBits),-1==l||k>=l)&&(k=-1)}else k=this.match_main(b,h,
-g);if(-1==k)e[f]=!1,c-=a[f].length2-a[f].length1;else if(e[f]=!0,c=k-g,g=-1==l?b.substring(k,k+h.length):b.substring(k,l+this.Match_MaxBits),h==g)b=b.substring(0,k)+this.diff_text2(a[f].diffs)+b.substring(k+h.length);else if(g=this.diff_main(h,g,!1),h.length>this.Match_MaxBits&&this.diff_levenshtein(g)/h.length>this.Patch_DeleteThreshold)e[f]=!1;else{this.diff_cleanupSemanticLossless(g);h=0;var m;for(l=0;l<a[f].diffs.length;l++){var p=a[f].diffs[l];p[0]!==DIFF_EQUAL&&(m=this.diff_xIndex(g,h));p[0]===
-DIFF_INSERT?b=b.substring(0,k+m)+p[1]+b.substring(k+m):p[0]===DIFF_DELETE&&(b=b.substring(0,k+m)+b.substring(k+this.diff_xIndex(g,h+p[1].length)));p[0]!==DIFF_DELETE&&(h+=p[1].length)}}}b=b.substring(d.length,b.length-d.length);return[b,e]};
-diff_match_patch.prototype.patch_addPadding=function(a){for(var b=this.Patch_Margin,d="",c=1;c<=b;c++)d+=String.fromCharCode(c);for(c=0;c<a.length;c++)a[c].start1+=b,a[c].start2+=b;c=a[0];var e=c.diffs;if(0==e.length||e[0][0]!=DIFF_EQUAL)e.unshift(new diff_match_patch.Diff(DIFF_EQUAL,d)),c.start1-=b,c.start2-=b,c.length1+=b,c.length2+=b;else if(b>e[0][1].length){var f=b-e[0][1].length;e[0][1]=d.substring(e[0][1].length)+e[0][1];c.start1-=f;c.start2-=f;c.length1+=f;c.length2+=f}c=a[a.length-1];e=c.diffs;
-0==e.length||e[e.length-1][0]!=DIFF_EQUAL?(e.push(new diff_match_patch.Diff(DIFF_EQUAL,d)),c.length1+=b,c.length2+=b):b>e[e.length-1][1].length&&(f=b-e[e.length-1][1].length,e[e.length-1][1]+=d.substring(0,f),c.length1+=f,c.length2+=f);return d};
-diff_match_patch.prototype.patch_splitMax=function(a){for(var b=this.Match_MaxBits,d=0;d<a.length;d++)if(!(a[d].length1<=b)){var c=a[d];a.splice(d--,1);for(var e=c.start1,f=c.start2,g="";0!==c.diffs.length;){var h=new diff_match_patch.patch_obj,l=!0;h.start1=e-g.length;h.start2=f-g.length;""!==g&&(h.length1=h.length2=g.length,h.diffs.push(new diff_match_patch.Diff(DIFF_EQUAL,g)));for(;0!==c.diffs.length&&h.length1<b-this.Patch_Margin;){g=c.diffs[0][0];var k=c.diffs[0][1];g===DIFF_INSERT?(h.length2+=
-k.length,f+=k.length,h.diffs.push(c.diffs.shift()),l=!1):g===DIFF_DELETE&&1==h.diffs.length&&h.diffs[0][0]==DIFF_EQUAL&&k.length>2*b?(h.length1+=k.length,e+=k.length,l=!1,h.diffs.push(new diff_match_patch.Diff(g,k)),c.diffs.shift()):(k=k.substring(0,b-h.length1-this.Patch_Margin),h.length1+=k.length,e+=k.length,g===DIFF_EQUAL?(h.length2+=k.length,f+=k.length):l=!1,h.diffs.push(new diff_match_patch.Diff(g,k)),k==c.diffs[0][1]?c.diffs.shift():c.diffs[0][1]=c.diffs[0][1].substring(k.length))}g=this.diff_text2(h.diffs);
-g=g.substring(g.length-this.Patch_Margin);k=this.diff_text1(c.diffs).substring(0,this.Patch_Margin);""!==k&&(h.length1+=k.length,h.length2+=k.length,0!==h.diffs.length&&h.diffs[h.diffs.length-1][0]===DIFF_EQUAL?h.diffs[h.diffs.length-1][1]+=k:h.diffs.push(new diff_match_patch.Diff(DIFF_EQUAL,k)));l||a.splice(++d,0,h)}}};diff_match_patch.prototype.patch_toText=function(a){for(var b=[],d=0;d<a.length;d++)b[d]=a[d];return b.join("")};
-diff_match_patch.prototype.patch_fromText=function(a){var b=[];if(!a)return b;a=a.split("\n");for(var d=0,c=/^@@ -(\d+),?(\d*) \+(\d+),?(\d*) @@$/;d<a.length;){var e=a[d].match(c);if(!e)throw Error("Invalid patch string: "+a[d]);var f=new diff_match_patch.patch_obj;b.push(f);f.start1=parseInt(e[1],10);""===e[2]?(f.start1--,f.length1=1):"0"==e[2]?f.length1=0:(f.start1--,f.length1=parseInt(e[2],10));f.start2=parseInt(e[3],10);""===e[4]?(f.start2--,f.length2=1):"0"==e[4]?f.length2=0:(f.start2--,f.length2=
-parseInt(e[4],10));for(d++;d<a.length;){e=a[d].charAt(0);try{var g=decodeURI(a[d].substring(1))}catch(h){throw Error("Illegal escape in patch_fromText: "+g);}if("-"==e)f.diffs.push(new diff_match_patch.Diff(DIFF_DELETE,g));else if("+"==e)f.diffs.push(new diff_match_patch.Diff(DIFF_INSERT,g));else if(" "==e)f.diffs.push(new diff_match_patch.Diff(DIFF_EQUAL,g));else if("@"==e)break;else if(""!==e)throw Error('Invalid patch mode "'+e+'" in: '+g);d++}}return b};
+diff_match_patch.prototype.diff_cleanupSemanticLossless=function(a){function b(a,b){if(!a||!b)return 6;var c=a.charAt(a.length-1),d=b.charAt(0),e=c.match(diff_match_patch.nonAlphaNumericRegex_),f=d.match(diff_match_patch.nonAlphaNumericRegex_),g=e&&c.match(diff_match_patch.whitespaceRegex_),h=f&&d.match(diff_match_patch.whitespaceRegex_);c=g&&c.match(diff_match_patch.linebreakRegex_);d=h&&d.match(diff_match_patch.linebreakRegex_);var k=c&&a.match(diff_match_patch.blanklineEndRegex_),l=d&&b.match(diff_match_patch.blanklineStartRegex_);
+return k||l?5:c||d?4:e&&!g&&h?3:g||h?2:e||f?1:0}for(var c=1;c<a.length-1;){if(a[c-1][0]==DIFF_EQUAL&&a[c+1][0]==DIFF_EQUAL){var d=a[c-1][1],e=a[c][1],f=a[c+1][1],g=this.diff_commonSuffix(d,e);if(g){var h=e.substring(e.length-g);d=d.substring(0,d.length-g);e=h+e.substring(0,e.length-g);f=h+f}g=d;h=e;for(var l=f,k=b(d,e)+b(e,f);e.charAt(0)===f.charAt(0);){d+=e.charAt(0);e=e.substring(1)+f.charAt(0);f=f.substring(1);var m=b(d,e)+b(e,f);m>=k&&(k=m,g=d,h=e,l=f)}a[c-1][1]!=g&&(g?a[c-1][1]=g:(a.splice(c-
+1,1),c--),a[c][1]=h,l?a[c+1][1]=l:(a.splice(c+1,1),c--))}c++}};diff_match_patch.nonAlphaNumericRegex_=/[^a-zA-Z0-9]/;diff_match_patch.whitespaceRegex_=/\s/;diff_match_patch.linebreakRegex_=/[\r\n]/;diff_match_patch.blanklineEndRegex_=/\n\r?\n$/;diff_match_patch.blanklineStartRegex_=/^\r?\n\r?\n/;
+diff_match_patch.prototype.diff_cleanupEfficiency=function(a){for(var b=!1,c=[],d=0,e=null,f=0,g=!1,h=!1,l=!1,k=!1;f<a.length;)a[f][0]==DIFF_EQUAL?(a[f][1].length<this.Diff_EditCost&&(l||k)?(c[d++]=f,g=l,h=k,e=a[f][1]):(d=0,e=null),l=k=!1):(a[f][0]==DIFF_DELETE?k=!0:l=!0,e&&(g&&h&&l&&k||e.length<this.Diff_EditCost/2&&3==g+h+l+k)&&(a.splice(c[d-1],0,new diff_match_patch.Diff(DIFF_DELETE,e)),a[c[d-1]+1][0]=DIFF_INSERT,d--,e=null,g&&h?(l=k=!0,d=0):(d--,f=0<d?c[d-1]:-1,l=k=!1),b=!0)),f++;b&&this.diff_cleanupMerge(a)};
+diff_match_patch.prototype.diff_cleanupMerge=function(a){a.push(new diff_match_patch.Diff(DIFF_EQUAL,""));for(var b=0,c=0,d=0,e="",f="",g;b<a.length;)switch(a[b][0]){case DIFF_INSERT:d++;f+=a[b][1];b++;break;case DIFF_DELETE:c++;e+=a[b][1];b++;break;case DIFF_EQUAL:1<c+d?(0!==c&&0!==d&&(g=this.diff_commonPrefix(f,e),0!==g&&(0<b-c-d&&a[b-c-d-1][0]==DIFF_EQUAL?a[b-c-d-1][1]+=f.substring(0,g):(a.splice(0,0,new diff_match_patch.Diff(DIFF_EQUAL,f.substring(0,g))),b++),f=f.substring(g),e=e.substring(g)),
+g=this.diff_commonSuffix(f,e),0!==g&&(a[b][1]=f.substring(f.length-g)+a[b][1],f=f.substring(0,f.length-g),e=e.substring(0,e.length-g))),b-=c+d,a.splice(b,c+d),e.length&&(a.splice(b,0,new diff_match_patch.Diff(DIFF_DELETE,e)),b++),f.length&&(a.splice(b,0,new diff_match_patch.Diff(DIFF_INSERT,f)),b++),b++):0!==b&&a[b-1][0]==DIFF_EQUAL?(a[b-1][1]+=a[b][1],a.splice(b,1)):b++,c=d=0,f=e=""}""===a[a.length-1][1]&&a.pop();c=!1;for(b=1;b<a.length-1;)a[b-1][0]==DIFF_EQUAL&&a[b+1][0]==DIFF_EQUAL&&(a[b][1].substring(a[b][1].length-
+a[b-1][1].length)==a[b-1][1]?(a[b][1]=a[b-1][1]+a[b][1].substring(0,a[b][1].length-a[b-1][1].length),a[b+1][1]=a[b-1][1]+a[b+1][1],a.splice(b-1,1),c=!0):a[b][1].substring(0,a[b+1][1].length)==a[b+1][1]&&(a[b-1][1]+=a[b+1][1],a[b][1]=a[b][1].substring(a[b+1][1].length)+a[b+1][1],a.splice(b+1,1),c=!0)),b++;c&&this.diff_cleanupMerge(a)};
+diff_match_patch.prototype.diff_xIndex=function(a,b){var c=0,d=0,e=0,f=0,g;for(g=0;g<a.length;g++){a[g][0]!==DIFF_INSERT&&(c+=a[g][1].length);a[g][0]!==DIFF_DELETE&&(d+=a[g][1].length);if(c>b)break;e=c;f=d}return a.length!=g&&a[g][0]===DIFF_DELETE?f:f+(b-e)};
+diff_match_patch.prototype.diff_prettyHtml=function(a){for(var b=[],c=/&/g,d=/</g,e=/>/g,f=/\n/g,g=0;g<a.length;g++){var h=a[g][0],l=a[g][1].replace(c,"&amp;").replace(d,"&lt;").replace(e,"&gt;").replace(f,"&para;<br>");switch(h){case DIFF_INSERT:b[g]='<ins style="background:#e6ffe6;">'+l+"</ins>";break;case DIFF_DELETE:b[g]='<del style="background:#ffe6e6;">'+l+"</del>";break;case DIFF_EQUAL:b[g]="<span>"+l+"</span>"}}return b.join("")};
+diff_match_patch.prototype.diff_text1=function(a){for(var b=[],c=0;c<a.length;c++)a[c][0]!==DIFF_INSERT&&(b[c]=a[c][1]);return b.join("")};diff_match_patch.prototype.diff_text2=function(a){for(var b=[],c=0;c<a.length;c++)a[c][0]!==DIFF_DELETE&&(b[c]=a[c][1]);return b.join("")};
+diff_match_patch.prototype.diff_levenshtein=function(a){for(var b=0,c=0,d=0,e=0;e<a.length;e++){var f=a[e][1];switch(a[e][0]){case DIFF_INSERT:c+=f.length;break;case DIFF_DELETE:d+=f.length;break;case DIFF_EQUAL:b+=Math.max(c,d),d=c=0}}return b+=Math.max(c,d)};diff_match_patch.prototype.isHighSurrogate=function(a){a=a.charCodeAt(0);return 55296<=a&&56319>=a};diff_match_patch.prototype.isLowSurrogate=function(a){a=a.charCodeAt(0);return 56320<=a&&57343>=a};
+diff_match_patch.prototype.diff_toDelta=function(a){for(var b=[],c,d=0;d<a.length;d++){var e=a[d],f=e[1][0],g=e[1][e[1].length-1];if(0!==e[1].length&&(g&&this.isHighSurrogate(g)&&(c=g,e[1]=e[1].slice(0,-1)),c&&f&&this.isHighSurrogate(c)&&this.isLowSurrogate(f)&&(e[1]=c+e[1]),DIFF_EQUAL===e[0]&&(c=g),0!==e[1].length))switch(e[0]){case DIFF_INSERT:b.push("+"+encodeURI(e[1]));break;case DIFF_DELETE:b.push("-"+e[1].length);break;case DIFF_EQUAL:b.push("="+e[1].length)}}return b.join("\t").replace(/%20/g,
+" ")};
+diff_match_patch.prototype.diff_fromDelta=function(a,b){for(var c=[],d=0,e=0,f=b.split(/\t/g),g=0;g<f.length;g++){var h=f[g].substring(1);switch(f[g].charAt(0)){case "+":try{c[d++]=new diff_match_patch.Diff(DIFF_INSERT,decodeURI(h))}catch(k){throw Error("Illegal escape in diff_fromDelta: "+h);}break;case "-":case "=":var l=parseInt(h,10);if(isNaN(l)||0>l)throw Error("Invalid number in diff_fromDelta: "+h);h=a.substring(e,e+=l);"="==f[g].charAt(0)?c[d++]=new diff_match_patch.Diff(DIFF_EQUAL,h):c[d++]=
+new diff_match_patch.Diff(DIFF_DELETE,h);break;default:if(f[g])throw Error("Invalid diff operation in diff_fromDelta: "+f[g]);}}if(e!=a.length)throw Error("Delta length ("+e+") does not equal source text length ("+a.length+").");return c};diff_match_patch.prototype.match_main=function(a,b,c){if(null==a||null==b||null==c)throw Error("Null input. (match_main)");c=Math.max(0,Math.min(c,a.length));return a==b?0:a.length?a.substring(c,c+b.length)==b?c:this.match_bitap_(a,b,c):-1};
+diff_match_patch.prototype.match_bitap_=function(a,b,c){function d(a,d){var e=a/b.length,g=Math.abs(c-d);return f.Match_Distance?e+g/f.Match_Distance:g?1:e}if(b.length>this.Match_MaxBits)throw Error("Pattern too long for this browser.");var e=this.match_alphabet_(b),f=this,g=this.Match_Threshold,h=a.indexOf(b,c);-1!=h&&(g=Math.min(d(0,h),g),h=a.lastIndexOf(b,c+b.length),-1!=h&&(g=Math.min(d(0,h),g)));var l=1<<b.length-1;h=-1;for(var k,m,p=b.length+a.length,x,w=0;w<b.length;w++){k=0;for(m=p;k<m;)d(w,
+c+m)<=g?k=m:p=m,m=Math.floor((p-k)/2+k);p=m;k=Math.max(1,c-m+1);var q=Math.min(c+m,a.length)+b.length;m=Array(q+2);for(m[q+1]=(1<<w)-1;q>=k;q--){var t=e[a.charAt(q-1)];m[q]=0===w?(m[q+1]<<1|1)&t:(m[q+1]<<1|1)&t|(x[q+1]|x[q])<<1|1|x[q+1];if(m[q]&l&&(t=d(w,q-1),t<=g))if(g=t,h=q-1,h>c)k=Math.max(1,2*c-h);else break}if(d(w+1,c)>g)break;x=m}return h};
+diff_match_patch.prototype.match_alphabet_=function(a){for(var b={},c=0;c<a.length;c++)b[a.charAt(c)]=0;for(c=0;c<a.length;c++)b[a.charAt(c)]|=1<<a.length-c-1;return b};
+diff_match_patch.prototype.patch_addContext_=function(a,b){if(0!=b.length){if(null===a.start2)throw Error("patch not initialized");for(var c=b.substring(a.start2,a.start2+a.length1),d=0;b.indexOf(c)!=b.lastIndexOf(c)&&c.length<this.Match_MaxBits-this.Patch_Margin-this.Patch_Margin;)d+=this.Patch_Margin,c=b.substring(a.start2-d,a.start2+a.length1+d);d+=this.Patch_Margin;(c=b.substring(a.start2-d,a.start2))&&a.diffs.unshift(new diff_match_patch.Diff(DIFF_EQUAL,c));(d=b.substring(a.start2+a.length1,
+a.start2+a.length1+d))&&a.diffs.push(new diff_match_patch.Diff(DIFF_EQUAL,d));a.start1-=c.length;a.start2-=c.length;a.length1+=c.length+d.length;a.length2+=c.length+d.length}};
+diff_match_patch.prototype.patch_make=function(a,b,c){if("string"==typeof a&&"string"==typeof b&&"undefined"==typeof c){var d=a;b=this.diff_main(d,b,!0);2<b.length&&(this.diff_cleanupSemantic(b),this.diff_cleanupEfficiency(b))}else if(a&&"object"==typeof a&&"undefined"==typeof b&&"undefined"==typeof c)b=a,d=this.diff_text1(b);else if("string"==typeof a&&b&&"object"==typeof b&&"undefined"==typeof c)d=a;else if("string"==typeof a&&"string"==typeof b&&c&&"object"==typeof c)d=a,b=c;else throw Error("Unknown call format to patch_make.");
+if(0===b.length)return[];c=[];a=new diff_match_patch.patch_obj;for(var e=0,f=0,g=0,h=d,l=0;l<b.length;l++){var k=b[l][0],m=b[l][1];e||k===DIFF_EQUAL||(a.start1=f,a.start2=g);switch(k){case DIFF_INSERT:a.diffs[e++]=b[l];a.length2+=m.length;d=d.substring(0,g)+m+d.substring(g);break;case DIFF_DELETE:a.length1+=m.length;a.diffs[e++]=b[l];d=d.substring(0,g)+d.substring(g+m.length);break;case DIFF_EQUAL:m.length<=2*this.Patch_Margin&&e&&b.length!=l+1?(a.diffs[e++]=b[l],a.length1+=m.length,a.length2+=m.length):
+m.length>=2*this.Patch_Margin&&e&&(this.patch_addContext_(a,h),c.push(a),a=new diff_match_patch.patch_obj,e=0,h=d,f=g)}k!==DIFF_INSERT&&(f+=m.length);k!==DIFF_DELETE&&(g+=m.length)}e&&(this.patch_addContext_(a,h),c.push(a));return c};
+diff_match_patch.prototype.patch_deepCopy=function(a){for(var b=[],c=0;c<a.length;c++){var d=a[c],e=new diff_match_patch.patch_obj;e.diffs=[];for(var f=0;f<d.diffs.length;f++)e.diffs[f]=new diff_match_patch.Diff(d.diffs[f][0],d.diffs[f][1]);e.start1=d.start1;e.start2=d.start2;e.length1=d.length1;e.length2=d.length2;b[c]=e}return b};
+diff_match_patch.prototype.patch_apply=function(a,b){if(0==a.length)return[b,[]];a=this.patch_deepCopy(a);var c=this.patch_addPadding(a);b=c+b+c;this.patch_splitMax(a);for(var d=0,e=[],f=0;f<a.length;f++){var g=a[f].start2+d,h=this.diff_text1(a[f].diffs),l=-1;if(h.length>this.Match_MaxBits){var k=this.match_main(b,h.substring(0,this.Match_MaxBits),g);-1!=k&&(l=this.match_main(b,h.substring(h.length-this.Match_MaxBits),g+h.length-this.Match_MaxBits),-1==l||k>=l)&&(k=-1)}else k=this.match_main(b,h,
+g);if(-1==k)e[f]=!1,d-=a[f].length2-a[f].length1;else if(e[f]=!0,d=k-g,g=-1==l?b.substring(k,k+h.length):b.substring(k,l+this.Match_MaxBits),h==g)b=b.substring(0,k)+this.diff_text2(a[f].diffs)+b.substring(k+h.length);else if(g=this.diff_main(h,g,!1),h.length>this.Match_MaxBits&&this.diff_levenshtein(g)/h.length>this.Patch_DeleteThreshold)e[f]=!1;else{this.diff_cleanupSemanticLossless(g);h=0;var m;for(l=0;l<a[f].diffs.length;l++){var p=a[f].diffs[l];p[0]!==DIFF_EQUAL&&(m=this.diff_xIndex(g,h));p[0]===
+DIFF_INSERT?b=b.substring(0,k+m)+p[1]+b.substring(k+m):p[0]===DIFF_DELETE&&(b=b.substring(0,k+m)+b.substring(k+this.diff_xIndex(g,h+p[1].length)));p[0]!==DIFF_DELETE&&(h+=p[1].length)}}}b=b.substring(c.length,b.length-c.length);return[b,e]};
+diff_match_patch.prototype.patch_addPadding=function(a){for(var b=this.Patch_Margin,c="",d=1;d<=b;d++)c+=String.fromCharCode(d);for(d=0;d<a.length;d++)a[d].start1+=b,a[d].start2+=b;d=a[0];var e=d.diffs;if(0==e.length||e[0][0]!=DIFF_EQUAL)e.unshift(new diff_match_patch.Diff(DIFF_EQUAL,c)),d.start1-=b,d.start2-=b,d.length1+=b,d.length2+=b;else if(b>e[0][1].length){var f=b-e[0][1].length;e[0][1]=c.substring(e[0][1].length)+e[0][1];d.start1-=f;d.start2-=f;d.length1+=f;d.length2+=f}d=a[a.length-1];e=d.diffs;
+0==e.length||e[e.length-1][0]!=DIFF_EQUAL?(e.push(new diff_match_patch.Diff(DIFF_EQUAL,c)),d.length1+=b,d.length2+=b):b>e[e.length-1][1].length&&(f=b-e[e.length-1][1].length,e[e.length-1][1]+=c.substring(0,f),d.length1+=f,d.length2+=f);return c};
+diff_match_patch.prototype.patch_splitMax=function(a){for(var b=this.Match_MaxBits,c=0;c<a.length;c++)if(!(a[c].length1<=b)){var d=a[c];a.splice(c--,1);for(var e=d.start1,f=d.start2,g="";0!==d.diffs.length;){var h=new diff_match_patch.patch_obj,l=!0;h.start1=e-g.length;h.start2=f-g.length;""!==g&&(h.length1=h.length2=g.length,h.diffs.push(new diff_match_patch.Diff(DIFF_EQUAL,g)));for(;0!==d.diffs.length&&h.length1<b-this.Patch_Margin;){g=d.diffs[0][0];var k=d.diffs[0][1];g===DIFF_INSERT?(h.length2+=
+k.length,f+=k.length,h.diffs.push(d.diffs.shift()),l=!1):g===DIFF_DELETE&&1==h.diffs.length&&h.diffs[0][0]==DIFF_EQUAL&&k.length>2*b?(h.length1+=k.length,e+=k.length,l=!1,h.diffs.push(new diff_match_patch.Diff(g,k)),d.diffs.shift()):(k=k.substring(0,b-h.length1-this.Patch_Margin),h.length1+=k.length,e+=k.length,g===DIFF_EQUAL?(h.length2+=k.length,f+=k.length):l=!1,h.diffs.push(new diff_match_patch.Diff(g,k)),k==d.diffs[0][1]?d.diffs.shift():d.diffs[0][1]=d.diffs[0][1].substring(k.length))}g=this.diff_text2(h.diffs);
+g=g.substring(g.length-this.Patch_Margin);k=this.diff_text1(d.diffs).substring(0,this.Patch_Margin);""!==k&&(h.length1+=k.length,h.length2+=k.length,0!==h.diffs.length&&h.diffs[h.diffs.length-1][0]===DIFF_EQUAL?h.diffs[h.diffs.length-1][1]+=k:h.diffs.push(new diff_match_patch.Diff(DIFF_EQUAL,k)));l||a.splice(++c,0,h)}}};diff_match_patch.prototype.patch_toText=function(a){for(var b=[],c=0;c<a.length;c++)b[c]=a[c];return b.join("")};
+diff_match_patch.prototype.patch_fromText=function(a){var b=[];if(!a)return b;a=a.split("\n");for(var c=0,d=/^@@ -(\d+),?(\d*) \+(\d+),?(\d*) @@$/;c<a.length;){var e=a[c].match(d);if(!e)throw Error("Invalid patch string: "+a[c]);var f=new diff_match_patch.patch_obj;b.push(f);f.start1=parseInt(e[1],10);""===e[2]?(f.start1--,f.length1=1):"0"==e[2]?f.length1=0:(f.start1--,f.length1=parseInt(e[2],10));f.start2=parseInt(e[3],10);""===e[4]?(f.start2--,f.length2=1):"0"==e[4]?f.length2=0:(f.start2--,f.length2=
+parseInt(e[4],10));for(c++;c<a.length;){e=a[c].charAt(0);try{var g=decodeURI(a[c].substring(1))}catch(h){throw Error("Illegal escape in patch_fromText: "+g);}if("-"==e)f.diffs.push(new diff_match_patch.Diff(DIFF_DELETE,g));else if("+"==e)f.diffs.push(new diff_match_patch.Diff(DIFF_INSERT,g));else if(" "==e)f.diffs.push(new diff_match_patch.Diff(DIFF_EQUAL,g));else if("@"==e)break;else if(""!==e)throw Error('Invalid patch mode "'+e+'" in: '+g);c++}}return b};
 diff_match_patch.patch_obj=function(){this.diffs=[];this.start2=this.start1=null;this.length2=this.length1=0};
-diff_match_patch.patch_obj.prototype.toString=function(){for(var a=["@@ -"+(0===this.length1?this.start1+",0":1==this.length1?this.start1+1:this.start1+1+","+this.length1)+" +"+(0===this.length2?this.start2+",0":1==this.length2?this.start2+1:this.start2+1+","+this.length2)+" @@\n"],b,d=0;d<this.diffs.length;d++){switch(this.diffs[d][0]){case DIFF_INSERT:b="+";break;case DIFF_DELETE:b="-";break;case DIFF_EQUAL:b=" "}a[d+1]=b+encodeURI(this.diffs[d][1])+"\n"}return a.join("").replace(/%20/g," ")};
-this.diff_match_patch=diff_match_patch;this.DIFF_DELETE=DIFF_DELETE;this.DIFF_INSERT=DIFF_INSERT;this.DIFF_EQUAL=DIFF_EQUAL;
+diff_match_patch.patch_obj.prototype.toString=function(){for(var a=["@@ -"+(0===this.length1?this.start1+",0":1==this.length1?this.start1+1:this.start1+1+","+this.length1)+" +"+(0===this.length2?this.start2+",0":1==this.length2?this.start2+1:this.start2+1+","+this.length2)+" @@\n"],b,c=0;c<this.diffs.length;c++){switch(this.diffs[c][0]){case DIFF_INSERT:b="+";break;case DIFF_DELETE:b="-";break;case DIFF_EQUAL:b=" "}a[c+1]=b+encodeURI(this.diffs[c][1])+"\n"}return a.join("").replace(/%20/g," ")};
+this.diff_match_patch=diff_match_patch;this.DIFF_DELETE=DIFF_DELETE;this.DIFF_INSERT=DIFF_INSERT;this.DIFF_EQUAL=DIFF_EQUAL;
\ No newline at end of file
diff --git a/javascript/diff_match_patch_uncompressed.js b/javascript/diff_match_patch_uncompressed.js
index 84a78e8..48c40cb 100644
--- a/javascript/diff_match_patch_uncompressed.js
+++ b/javascript/diff_match_patch_uncompressed.js
@@ -1366,7 +1366,14 @@ diff_match_patch.prototype.diff_toDelta = function(diffs) {
     var thisTop = thisDiff[1][0];
     var thisEnd = thisDiff[1][thisDiff[1].length - 1];
 
+    if (0 === thisDiff[1].length) {
+      continue;
+    }
+
+    // trap a trailing high-surrogate so we can
+    // distribute it to the successive edits
     if (thisEnd && this.isHighSurrogate(thisEnd)) {
+      lastEnd = thisEnd;
       thisDiff[1] = thisDiff[1].slice(0, -1);
     }
 
@@ -1374,20 +1381,25 @@ diff_match_patch.prototype.diff_toDelta = function(diffs) {
       thisDiff[1] = lastEnd + thisDiff[1];
     }
 
-    lastEnd = thisEnd;
-    if ( 0 === thisDiff[1].length ) {
+    // we have to carry the surrogate half through
+    // any successive insert/delete edits
+    if (DIFF_EQUAL === thisDiff[0]) {
+      lastEnd = thisEnd;
+    }
+
+    if (0 === thisDiff[1].length) {
       continue;
     }
 
-    switch (diffs[x][0]) {
+    switch (thisDiff[0]) {
       case DIFF_INSERT:
-        text[x] = '+' + encodeURI(diffs[x][1]);
+        text.push('+' + encodeURI(thisDiff[1]));
         break;
       case DIFF_DELETE:
-        text[x] = '-' + diffs[x][1].length;
+        text.push('-' + thisDiff[1].length);
         break;
       case DIFF_EQUAL:
-        text[x] = '=' + diffs[x][1].length;
+        text.push('=' + thisDiff[1].length);
         break;
     }
   }
diff --git a/javascript/tests/diff_match_patch_test.js b/javascript/tests/diff_match_patch_test.js
index c48f3bb..4283f9d 100644
--- a/javascript/tests/diff_match_patch_test.js
+++ b/javascript/tests/diff_match_patch_test.js
@@ -548,7 +548,44 @@ function testDiffDelta() {
       newText = applyRandomTextEdit(originalText);
       dmp.patch_toText(dmp.patch_make(originalText, newText));
     }
-  });
+  })();
+
+  // Unicode - splitting surrogates
+  try {
+    assertEquivalent(
+      dmp.diff_toDelta([[DIFF_EQUAL,'\ud83c\udd70'], [DIFF_INSERT, '\ud83c\udd70'], [DIFF_EQUAL, '\ud83c\udd71']]),
+      dmp.diff_toDelta(dmp.diff_main('\ud83c\udd70\ud83c\udd71', '\ud83c\udd70\ud83c\udd70\ud83c\udd71'))
+    );
+  } catch ( e ) {
+    assertEquals('Inserting similar surrogate pair', 'crashed');
+  }
+
+  try {
+    assertEquivalent(
+      dmp.diff_toDelta([[DIFF_DELETE, '\ud83c\udd70'], [DIFF_INSERT, '\ud83c\udd71']]),
+      dmp.diff_toDelta([[DIFF_EQUAL, '\ud83c'], [DIFF_DELETE, '\udd70'], [DIFF_INSERT, '\udd71']]),
+    );
+  } catch ( e ) {
+    assertEquals('Swap surrogate pair', 'crashed');
+  }
+
+  try {
+    assertEquivalent(
+      dmp.diff_toDelta([[DIFF_INSERT, '\ud83c\udd70'], [DIFF_DELETE, '\ud83c\udd71']]),
+      dmp.diff_toDelta([[DIFF_EQUAL, '\ud83c'], [DIFF_INSERT, '\udd70'], [DIFF_DELETE, '\udd71']]),
+    );
+  } catch ( e ) {
+    assertEquals('Swap surrogate pair', 'crashed');
+  }
+
+  // Empty diff groups
+  assertEquivalent(
+    JSON.stringify(dmp.diff_toDelta([[DIFF_EQUAL, 'abcdef'], [DIFF_DELETE, ''], [DIFF_INSERT, 'ghijk']])),
+    JSON.stringify(dmp.diff_toDelta([[DIFF_EQUAL, 'abcdef'], [DIFF_INSERT, 'ghijk']])),
+  );
+
+  // Invalid UTF8 but valid surrogate pairs
+  
 
   // Verify pool of unchanged characters.
   diffs = [[DIFF_INSERT, 'A-Z a-z 0-9 - _ . ! ~ * \' ( ) ; / ? : @ & = + $ , # ']];

From 55a8779c7432a0ffc5f81991d980096ede39cc22 Mon Sep 17 00:00:00 2001
From: Dennis Snell <dennis.snell@automattic.com>
Date: Thu, 12 Dec 2019 23:23:23 -0700
Subject: [PATCH 14/34] Augment diff_fromDelta with custom decodeURI for
 encoded surrogate halves

Because sometimes we get a patch that was built in Python or another
library that will happily URI-encode half of a surrogate pair.
---
 javascript/diff_match_patch.js              | 103 ++++++++++----------
 javascript/diff_match_patch_uncompressed.js |  96 +++++++++++++++++-
 javascript/tests/diff_match_patch_test.js   |  16 ++-
 3 files changed, 160 insertions(+), 55 deletions(-)

diff --git a/javascript/diff_match_patch.js b/javascript/diff_match_patch.js
index 4ba112a..37bd784 100644
--- a/javascript/diff_match_patch.js
+++ b/javascript/diff_match_patch.js
@@ -1,56 +1,59 @@
 var diff_match_patch=function(){this.Diff_Timeout=1;this.Diff_EditCost=4;this.Match_Threshold=.5;this.Match_Distance=1E3;this.Patch_DeleteThreshold=.5;this.Patch_Margin=4;this.Match_MaxBits=32},DIFF_DELETE=-1,DIFF_INSERT=1,DIFF_EQUAL=0;diff_match_patch.Diff=function(a,b){this[0]=a;this[1]=b};diff_match_patch.Diff.prototype.length=2;diff_match_patch.Diff.prototype.toString=function(){return this[0]+","+this[1]};
-diff_match_patch.prototype.diff_main=function(a,b,c,d){"undefined"==typeof d&&(d=0>=this.Diff_Timeout?Number.MAX_VALUE:(new Date).getTime()+1E3*this.Diff_Timeout);if(null==a||null==b)throw Error("Null input. (diff_main)");if(a==b)return a?[new diff_match_patch.Diff(DIFF_EQUAL,a)]:[];"undefined"==typeof c&&(c=!0);var e=c,f=this.diff_commonPrefix(a,b);c=a.substring(0,f);a=a.substring(f);b=b.substring(f);f=this.diff_commonSuffix(a,b);var g=a.substring(a.length-f);a=a.substring(0,a.length-f);b=b.substring(0,
-b.length-f);a=this.diff_compute_(a,b,e,d);c&&a.unshift(new diff_match_patch.Diff(DIFF_EQUAL,c));g&&a.push(new diff_match_patch.Diff(DIFF_EQUAL,g));this.diff_cleanupMerge(a);return a};
-diff_match_patch.prototype.diff_compute_=function(a,b,c,d){if(!a)return[new diff_match_patch.Diff(DIFF_INSERT,b)];if(!b)return[new diff_match_patch.Diff(DIFF_DELETE,a)];var e=a.length>b.length?a:b,f=a.length>b.length?b:a,g=e.indexOf(f);return-1!=g?(c=[new diff_match_patch.Diff(DIFF_INSERT,e.substring(0,g)),new diff_match_patch.Diff(DIFF_EQUAL,f),new diff_match_patch.Diff(DIFF_INSERT,e.substring(g+f.length))],a.length>b.length&&(c[0][0]=c[2][0]=DIFF_DELETE),c):1==f.length?[new diff_match_patch.Diff(DIFF_DELETE,
-a),new diff_match_patch.Diff(DIFF_INSERT,b)]:(e=this.diff_halfMatch_(a,b))?(b=e[1],f=e[3],a=e[4],e=this.diff_main(e[0],e[2],c,d),c=this.diff_main(b,f,c,d),e.concat([new diff_match_patch.Diff(DIFF_EQUAL,a)],c)):c&&100<a.length&&100<b.length?this.diff_lineMode_(a,b,d):this.diff_bisect_(a,b,d)};
-diff_match_patch.prototype.diff_lineMode_=function(a,b,c){var d=this.diff_linesToChars_(a,b);a=d.chars1;b=d.chars2;d=d.lineArray;a=this.diff_main(a,b,!1,c);this.diff_charsToLines_(a,d);this.diff_cleanupSemantic(a);a.push(new diff_match_patch.Diff(DIFF_EQUAL,""));for(var e=d=b=0,f="",g="";b<a.length;){switch(a[b][0]){case DIFF_INSERT:e++;g+=a[b][1];break;case DIFF_DELETE:d++;f+=a[b][1];break;case DIFF_EQUAL:if(1<=d&&1<=e){a.splice(b-d-e,d+e);b=b-d-e;d=this.diff_main(f,g,!1,c);for(e=d.length-1;0<=e;e--)a.splice(b,
-0,d[e]);b+=d.length}d=e=0;g=f=""}b++}a.pop();return a};
-diff_match_patch.prototype.diff_bisect_=function(a,b,c){for(var d=a.length,e=b.length,f=Math.ceil((d+e)/2),g=2*f,h=Array(g),l=Array(g),k=0;k<g;k++)h[k]=-1,l[k]=-1;h[f+1]=0;l[f+1]=0;k=d-e;for(var m=0!=k%2,p=0,x=0,w=0,q=0,t=0;t<f&&!((new Date).getTime()>c);t++){for(var v=-t+p;v<=t-x;v+=2){var n=f+v;var r=v==-t||v!=t&&h[n-1]<h[n+1]?h[n+1]:h[n-1]+1;for(var y=r-v;r<d&&y<e&&a.charAt(r)==b.charAt(y);)r++,y++;h[n]=r;if(r>d)x+=2;else if(y>e)p+=2;else if(m&&(n=f+k-v,0<=n&&n<g&&-1!=l[n])){var u=d-l[n];if(r>=
-u)return this.diff_bisectSplit_(a,b,r,y,c)}}for(v=-t+w;v<=t-q;v+=2){n=f+v;u=v==-t||v!=t&&l[n-1]<l[n+1]?l[n+1]:l[n-1]+1;for(r=u-v;u<d&&r<e&&a.charAt(d-u-1)==b.charAt(e-r-1);)u++,r++;l[n]=u;if(u>d)q+=2;else if(r>e)w+=2;else if(!m&&(n=f+k-v,0<=n&&n<g&&-1!=h[n]&&(r=h[n],y=f+r-n,u=d-u,r>=u)))return this.diff_bisectSplit_(a,b,r,y,c)}}return[new diff_match_patch.Diff(DIFF_DELETE,a),new diff_match_patch.Diff(DIFF_INSERT,b)]};
-diff_match_patch.prototype.diff_bisectSplit_=function(a,b,c,d,e){var f=a.substring(0,c),g=b.substring(0,d);a=a.substring(c);b=b.substring(d);f=this.diff_main(f,g,!1,e);e=this.diff_main(a,b,!1,e);return f.concat(e)};
-diff_match_patch.prototype.diff_linesToChars_=function(a,b){function c(a){for(var b="",c=0,g=-1,h=d.length;g<a.length-1;){g=a.indexOf("\n",c);-1==g&&(g=a.length-1);var l=a.substring(c,g+1);(e.hasOwnProperty?e.hasOwnProperty(l):void 0!==e[l])?b+=String.fromCharCode(e[l]):(h==f&&(l=a.substring(c),g=a.length),b+=String.fromCharCode(h),e[l]=h,d[h++]=l);c=g+1}return b}var d=[],e={};d[0]="";var f=4E4,g=c(a);f=65535;var h=c(b);return{chars1:g,chars2:h,lineArray:d}};
-diff_match_patch.prototype.diff_charsToLines_=function(a,b){for(var c=0;c<a.length;c++){for(var d=a[c][1],e=[],f=0;f<d.length;f++)e[f]=b[d.charCodeAt(f)];a[c][1]=e.join("")}};diff_match_patch.prototype.diff_commonPrefix=function(a,b){if(!a||!b||a.charAt(0)!=b.charAt(0))return 0;for(var c=0,d=Math.min(a.length,b.length),e=d,f=0;c<e;)a.substring(f,e)==b.substring(f,e)?f=c=e:d=e,e=Math.floor((d-c)/2+c);return e};
-diff_match_patch.prototype.diff_commonSuffix=function(a,b){if(!a||!b||a.charAt(a.length-1)!=b.charAt(b.length-1))return 0;for(var c=0,d=Math.min(a.length,b.length),e=d,f=0;c<e;)a.substring(a.length-e,a.length-f)==b.substring(b.length-e,b.length-f)?f=c=e:d=e,e=Math.floor((d-c)/2+c);return e};
-diff_match_patch.prototype.diff_commonOverlap_=function(a,b){var c=a.length,d=b.length;if(0==c||0==d)return 0;c>d?a=a.substring(c-d):c<d&&(b=b.substring(0,c));c=Math.min(c,d);if(a==b)return c;d=0;for(var e=1;;){var f=a.substring(c-e);f=b.indexOf(f);if(-1==f)return d;e+=f;if(0==f||a.substring(c-e)==b.substring(0,e))d=e,e++}};
-diff_match_patch.prototype.diff_halfMatch_=function(a,b){function c(a,b,c){for(var d=a.substring(c,c+Math.floor(a.length/4)),e=-1,g="",h,k,l,m;-1!=(e=b.indexOf(d,e+1));){var p=f.diff_commonPrefix(a.substring(c),b.substring(e)),u=f.diff_commonSuffix(a.substring(0,c),b.substring(0,e));g.length<u+p&&(g=b.substring(e-u,e)+b.substring(e,e+p),h=a.substring(0,c-u),k=a.substring(c+p),l=b.substring(0,e-u),m=b.substring(e+p))}return 2*g.length>=a.length?[h,k,l,m,g]:null}if(0>=this.Diff_Timeout)return null;
-var d=a.length>b.length?a:b,e=a.length>b.length?b:a;if(4>d.length||2*e.length<d.length)return null;var f=this,g=c(d,e,Math.ceil(d.length/4));d=c(d,e,Math.ceil(d.length/2));if(g||d)g=d?g?g[4].length>d[4].length?g:d:d:g;else return null;if(a.length>b.length){d=g[0];e=g[1];var h=g[2];var l=g[3]}else h=g[0],l=g[1],d=g[2],e=g[3];return[d,e,h,l,g[4]]};
-diff_match_patch.prototype.diff_cleanupSemantic=function(a){for(var b=!1,c=[],d=0,e=null,f=0,g=0,h=0,l=0,k=0;f<a.length;)a[f][0]==DIFF_EQUAL?(c[d++]=f,g=l,h=k,k=l=0,e=a[f][1]):(a[f][0]==DIFF_INSERT?l+=a[f][1].length:k+=a[f][1].length,e&&e.length<=Math.max(g,h)&&e.length<=Math.max(l,k)&&(a.splice(c[d-1],0,new diff_match_patch.Diff(DIFF_DELETE,e)),a[c[d-1]+1][0]=DIFF_INSERT,d--,d--,f=0<d?c[d-1]:-1,k=l=h=g=0,e=null,b=!0)),f++;b&&this.diff_cleanupMerge(a);this.diff_cleanupSemanticLossless(a);for(f=1;f<
-a.length;){if(a[f-1][0]==DIFF_DELETE&&a[f][0]==DIFF_INSERT){b=a[f-1][1];c=a[f][1];d=this.diff_commonOverlap_(b,c);e=this.diff_commonOverlap_(c,b);if(d>=e){if(d>=b.length/2||d>=c.length/2)a.splice(f,0,new diff_match_patch.Diff(DIFF_EQUAL,c.substring(0,d))),a[f-1][1]=b.substring(0,b.length-d),a[f+1][1]=c.substring(d),f++}else if(e>=b.length/2||e>=c.length/2)a.splice(f,0,new diff_match_patch.Diff(DIFF_EQUAL,b.substring(0,e))),a[f-1][0]=DIFF_INSERT,a[f-1][1]=c.substring(0,c.length-e),a[f+1][0]=DIFF_DELETE,
+diff_match_patch.prototype.diff_main=function(a,b,d,c){"undefined"==typeof c&&(c=0>=this.Diff_Timeout?Number.MAX_VALUE:(new Date).getTime()+1E3*this.Diff_Timeout);if(null==a||null==b)throw Error("Null input. (diff_main)");if(a==b)return a?[new diff_match_patch.Diff(DIFF_EQUAL,a)]:[];"undefined"==typeof d&&(d=!0);var e=d,f=this.diff_commonPrefix(a,b);d=a.substring(0,f);a=a.substring(f);b=b.substring(f);f=this.diff_commonSuffix(a,b);var g=a.substring(a.length-f);a=a.substring(0,a.length-f);b=b.substring(0,
+b.length-f);a=this.diff_compute_(a,b,e,c);d&&a.unshift(new diff_match_patch.Diff(DIFF_EQUAL,d));g&&a.push(new diff_match_patch.Diff(DIFF_EQUAL,g));this.diff_cleanupMerge(a);return a};
+diff_match_patch.prototype.diff_compute_=function(a,b,d,c){if(!a)return[new diff_match_patch.Diff(DIFF_INSERT,b)];if(!b)return[new diff_match_patch.Diff(DIFF_DELETE,a)];var e=a.length>b.length?a:b,f=a.length>b.length?b:a,g=e.indexOf(f);return-1!=g?(d=[new diff_match_patch.Diff(DIFF_INSERT,e.substring(0,g)),new diff_match_patch.Diff(DIFF_EQUAL,f),new diff_match_patch.Diff(DIFF_INSERT,e.substring(g+f.length))],a.length>b.length&&(d[0][0]=d[2][0]=DIFF_DELETE),d):1==f.length?[new diff_match_patch.Diff(DIFF_DELETE,
+a),new diff_match_patch.Diff(DIFF_INSERT,b)]:(e=this.diff_halfMatch_(a,b))?(b=e[1],f=e[3],a=e[4],e=this.diff_main(e[0],e[2],d,c),d=this.diff_main(b,f,d,c),e.concat([new diff_match_patch.Diff(DIFF_EQUAL,a)],d)):d&&100<a.length&&100<b.length?this.diff_lineMode_(a,b,c):this.diff_bisect_(a,b,c)};
+diff_match_patch.prototype.diff_lineMode_=function(a,b,d){var c=this.diff_linesToChars_(a,b);a=c.chars1;b=c.chars2;c=c.lineArray;a=this.diff_main(a,b,!1,d);this.diff_charsToLines_(a,c);this.diff_cleanupSemantic(a);a.push(new diff_match_patch.Diff(DIFF_EQUAL,""));for(var e=c=b=0,f="",g="";b<a.length;){switch(a[b][0]){case DIFF_INSERT:e++;g+=a[b][1];break;case DIFF_DELETE:c++;f+=a[b][1];break;case DIFF_EQUAL:if(1<=c&&1<=e){a.splice(b-c-e,c+e);b=b-c-e;c=this.diff_main(f,g,!1,d);for(e=c.length-1;0<=e;e--)a.splice(b,
+0,c[e]);b+=c.length}c=e=0;g=f=""}b++}a.pop();return a};
+diff_match_patch.prototype.diff_bisect_=function(a,b,d){for(var c=a.length,e=b.length,f=Math.ceil((c+e)/2),g=2*f,h=Array(g),l=Array(g),k=0;k<g;k++)h[k]=-1,l[k]=-1;h[f+1]=0;l[f+1]=0;k=c-e;for(var m=0!=k%2,p=0,x=0,w=0,q=0,t=0;t<f&&!((new Date).getTime()>d);t++){for(var v=-t+p;v<=t-x;v+=2){var n=f+v;var r=v==-t||v!=t&&h[n-1]<h[n+1]?h[n+1]:h[n-1]+1;for(var y=r-v;r<c&&y<e&&a.charAt(r)==b.charAt(y);)r++,y++;h[n]=r;if(r>c)x+=2;else if(y>e)p+=2;else if(m&&(n=f+k-v,0<=n&&n<g&&-1!=l[n])){var u=c-l[n];if(r>=
+u)return this.diff_bisectSplit_(a,b,r,y,d)}}for(v=-t+w;v<=t-q;v+=2){n=f+v;u=v==-t||v!=t&&l[n-1]<l[n+1]?l[n+1]:l[n-1]+1;for(r=u-v;u<c&&r<e&&a.charAt(c-u-1)==b.charAt(e-r-1);)u++,r++;l[n]=u;if(u>c)q+=2;else if(r>e)w+=2;else if(!m&&(n=f+k-v,0<=n&&n<g&&-1!=h[n]&&(r=h[n],y=f+r-n,u=c-u,r>=u)))return this.diff_bisectSplit_(a,b,r,y,d)}}return[new diff_match_patch.Diff(DIFF_DELETE,a),new diff_match_patch.Diff(DIFF_INSERT,b)]};
+diff_match_patch.prototype.diff_bisectSplit_=function(a,b,d,c,e){var f=a.substring(0,d),g=b.substring(0,c);a=a.substring(d);b=b.substring(c);f=this.diff_main(f,g,!1,e);e=this.diff_main(a,b,!1,e);return f.concat(e)};
+diff_match_patch.prototype.diff_linesToChars_=function(a,b){function d(a){for(var b="",d=0,g=-1,h=c.length;g<a.length-1;){g=a.indexOf("\n",d);-1==g&&(g=a.length-1);var l=a.substring(d,g+1);(e.hasOwnProperty?e.hasOwnProperty(l):void 0!==e[l])?b+=String.fromCharCode(e[l]):(h==f&&(l=a.substring(d),g=a.length),b+=String.fromCharCode(h),e[l]=h,c[h++]=l);d=g+1}return b}var c=[],e={};c[0]="";var f=4E4,g=d(a);f=65535;var h=d(b);return{chars1:g,chars2:h,lineArray:c}};
+diff_match_patch.prototype.diff_charsToLines_=function(a,b){for(var d=0;d<a.length;d++){for(var c=a[d][1],e=[],f=0;f<c.length;f++)e[f]=b[c.charCodeAt(f)];a[d][1]=e.join("")}};diff_match_patch.prototype.diff_commonPrefix=function(a,b){if(!a||!b||a.charAt(0)!=b.charAt(0))return 0;for(var d=0,c=Math.min(a.length,b.length),e=c,f=0;d<e;)a.substring(f,e)==b.substring(f,e)?f=d=e:c=e,e=Math.floor((c-d)/2+d);return e};
+diff_match_patch.prototype.diff_commonSuffix=function(a,b){if(!a||!b||a.charAt(a.length-1)!=b.charAt(b.length-1))return 0;for(var d=0,c=Math.min(a.length,b.length),e=c,f=0;d<e;)a.substring(a.length-e,a.length-f)==b.substring(b.length-e,b.length-f)?f=d=e:c=e,e=Math.floor((c-d)/2+d);return e};
+diff_match_patch.prototype.diff_commonOverlap_=function(a,b){var d=a.length,c=b.length;if(0==d||0==c)return 0;d>c?a=a.substring(d-c):d<c&&(b=b.substring(0,d));d=Math.min(d,c);if(a==b)return d;c=0;for(var e=1;;){var f=a.substring(d-e);f=b.indexOf(f);if(-1==f)return c;e+=f;if(0==f||a.substring(d-e)==b.substring(0,e))c=e,e++}};
+diff_match_patch.prototype.diff_halfMatch_=function(a,b){function d(a,b,c){for(var d=a.substring(c,c+Math.floor(a.length/4)),e=-1,g="",h,k,l,m;-1!=(e=b.indexOf(d,e+1));){var p=f.diff_commonPrefix(a.substring(c),b.substring(e)),u=f.diff_commonSuffix(a.substring(0,c),b.substring(0,e));g.length<u+p&&(g=b.substring(e-u,e)+b.substring(e,e+p),h=a.substring(0,c-u),k=a.substring(c+p),l=b.substring(0,e-u),m=b.substring(e+p))}return 2*g.length>=a.length?[h,k,l,m,g]:null}if(0>=this.Diff_Timeout)return null;
+var c=a.length>b.length?a:b,e=a.length>b.length?b:a;if(4>c.length||2*e.length<c.length)return null;var f=this,g=d(c,e,Math.ceil(c.length/4));c=d(c,e,Math.ceil(c.length/2));if(g||c)g=c?g?g[4].length>c[4].length?g:c:c:g;else return null;if(a.length>b.length){c=g[0];e=g[1];var h=g[2];var l=g[3]}else h=g[0],l=g[1],c=g[2],e=g[3];return[c,e,h,l,g[4]]};
+diff_match_patch.prototype.diff_cleanupSemantic=function(a){for(var b=!1,d=[],c=0,e=null,f=0,g=0,h=0,l=0,k=0;f<a.length;)a[f][0]==DIFF_EQUAL?(d[c++]=f,g=l,h=k,k=l=0,e=a[f][1]):(a[f][0]==DIFF_INSERT?l+=a[f][1].length:k+=a[f][1].length,e&&e.length<=Math.max(g,h)&&e.length<=Math.max(l,k)&&(a.splice(d[c-1],0,new diff_match_patch.Diff(DIFF_DELETE,e)),a[d[c-1]+1][0]=DIFF_INSERT,c--,c--,f=0<c?d[c-1]:-1,k=l=h=g=0,e=null,b=!0)),f++;b&&this.diff_cleanupMerge(a);this.diff_cleanupSemanticLossless(a);for(f=1;f<
+a.length;){if(a[f-1][0]==DIFF_DELETE&&a[f][0]==DIFF_INSERT){b=a[f-1][1];d=a[f][1];c=this.diff_commonOverlap_(b,d);e=this.diff_commonOverlap_(d,b);if(c>=e){if(c>=b.length/2||c>=d.length/2)a.splice(f,0,new diff_match_patch.Diff(DIFF_EQUAL,d.substring(0,c))),a[f-1][1]=b.substring(0,b.length-c),a[f+1][1]=d.substring(c),f++}else if(e>=b.length/2||e>=d.length/2)a.splice(f,0,new diff_match_patch.Diff(DIFF_EQUAL,b.substring(0,e))),a[f-1][0]=DIFF_INSERT,a[f-1][1]=d.substring(0,d.length-e),a[f+1][0]=DIFF_DELETE,
 a[f+1][1]=b.substring(e),f++;f++}f++}};
 diff_match_patch.prototype.diff_cleanupSemanticLossless=function(a){function b(a,b){if(!a||!b)return 6;var c=a.charAt(a.length-1),d=b.charAt(0),e=c.match(diff_match_patch.nonAlphaNumericRegex_),f=d.match(diff_match_patch.nonAlphaNumericRegex_),g=e&&c.match(diff_match_patch.whitespaceRegex_),h=f&&d.match(diff_match_patch.whitespaceRegex_);c=g&&c.match(diff_match_patch.linebreakRegex_);d=h&&d.match(diff_match_patch.linebreakRegex_);var k=c&&a.match(diff_match_patch.blanklineEndRegex_),l=d&&b.match(diff_match_patch.blanklineStartRegex_);
-return k||l?5:c||d?4:e&&!g&&h?3:g||h?2:e||f?1:0}for(var c=1;c<a.length-1;){if(a[c-1][0]==DIFF_EQUAL&&a[c+1][0]==DIFF_EQUAL){var d=a[c-1][1],e=a[c][1],f=a[c+1][1],g=this.diff_commonSuffix(d,e);if(g){var h=e.substring(e.length-g);d=d.substring(0,d.length-g);e=h+e.substring(0,e.length-g);f=h+f}g=d;h=e;for(var l=f,k=b(d,e)+b(e,f);e.charAt(0)===f.charAt(0);){d+=e.charAt(0);e=e.substring(1)+f.charAt(0);f=f.substring(1);var m=b(d,e)+b(e,f);m>=k&&(k=m,g=d,h=e,l=f)}a[c-1][1]!=g&&(g?a[c-1][1]=g:(a.splice(c-
-1,1),c--),a[c][1]=h,l?a[c+1][1]=l:(a.splice(c+1,1),c--))}c++}};diff_match_patch.nonAlphaNumericRegex_=/[^a-zA-Z0-9]/;diff_match_patch.whitespaceRegex_=/\s/;diff_match_patch.linebreakRegex_=/[\r\n]/;diff_match_patch.blanklineEndRegex_=/\n\r?\n$/;diff_match_patch.blanklineStartRegex_=/^\r?\n\r?\n/;
-diff_match_patch.prototype.diff_cleanupEfficiency=function(a){for(var b=!1,c=[],d=0,e=null,f=0,g=!1,h=!1,l=!1,k=!1;f<a.length;)a[f][0]==DIFF_EQUAL?(a[f][1].length<this.Diff_EditCost&&(l||k)?(c[d++]=f,g=l,h=k,e=a[f][1]):(d=0,e=null),l=k=!1):(a[f][0]==DIFF_DELETE?k=!0:l=!0,e&&(g&&h&&l&&k||e.length<this.Diff_EditCost/2&&3==g+h+l+k)&&(a.splice(c[d-1],0,new diff_match_patch.Diff(DIFF_DELETE,e)),a[c[d-1]+1][0]=DIFF_INSERT,d--,e=null,g&&h?(l=k=!0,d=0):(d--,f=0<d?c[d-1]:-1,l=k=!1),b=!0)),f++;b&&this.diff_cleanupMerge(a)};
-diff_match_patch.prototype.diff_cleanupMerge=function(a){a.push(new diff_match_patch.Diff(DIFF_EQUAL,""));for(var b=0,c=0,d=0,e="",f="",g;b<a.length;)switch(a[b][0]){case DIFF_INSERT:d++;f+=a[b][1];b++;break;case DIFF_DELETE:c++;e+=a[b][1];b++;break;case DIFF_EQUAL:1<c+d?(0!==c&&0!==d&&(g=this.diff_commonPrefix(f,e),0!==g&&(0<b-c-d&&a[b-c-d-1][0]==DIFF_EQUAL?a[b-c-d-1][1]+=f.substring(0,g):(a.splice(0,0,new diff_match_patch.Diff(DIFF_EQUAL,f.substring(0,g))),b++),f=f.substring(g),e=e.substring(g)),
-g=this.diff_commonSuffix(f,e),0!==g&&(a[b][1]=f.substring(f.length-g)+a[b][1],f=f.substring(0,f.length-g),e=e.substring(0,e.length-g))),b-=c+d,a.splice(b,c+d),e.length&&(a.splice(b,0,new diff_match_patch.Diff(DIFF_DELETE,e)),b++),f.length&&(a.splice(b,0,new diff_match_patch.Diff(DIFF_INSERT,f)),b++),b++):0!==b&&a[b-1][0]==DIFF_EQUAL?(a[b-1][1]+=a[b][1],a.splice(b,1)):b++,c=d=0,f=e=""}""===a[a.length-1][1]&&a.pop();c=!1;for(b=1;b<a.length-1;)a[b-1][0]==DIFF_EQUAL&&a[b+1][0]==DIFF_EQUAL&&(a[b][1].substring(a[b][1].length-
-a[b-1][1].length)==a[b-1][1]?(a[b][1]=a[b-1][1]+a[b][1].substring(0,a[b][1].length-a[b-1][1].length),a[b+1][1]=a[b-1][1]+a[b+1][1],a.splice(b-1,1),c=!0):a[b][1].substring(0,a[b+1][1].length)==a[b+1][1]&&(a[b-1][1]+=a[b+1][1],a[b][1]=a[b][1].substring(a[b+1][1].length)+a[b+1][1],a.splice(b+1,1),c=!0)),b++;c&&this.diff_cleanupMerge(a)};
-diff_match_patch.prototype.diff_xIndex=function(a,b){var c=0,d=0,e=0,f=0,g;for(g=0;g<a.length;g++){a[g][0]!==DIFF_INSERT&&(c+=a[g][1].length);a[g][0]!==DIFF_DELETE&&(d+=a[g][1].length);if(c>b)break;e=c;f=d}return a.length!=g&&a[g][0]===DIFF_DELETE?f:f+(b-e)};
-diff_match_patch.prototype.diff_prettyHtml=function(a){for(var b=[],c=/&/g,d=/</g,e=/>/g,f=/\n/g,g=0;g<a.length;g++){var h=a[g][0],l=a[g][1].replace(c,"&amp;").replace(d,"&lt;").replace(e,"&gt;").replace(f,"&para;<br>");switch(h){case DIFF_INSERT:b[g]='<ins style="background:#e6ffe6;">'+l+"</ins>";break;case DIFF_DELETE:b[g]='<del style="background:#ffe6e6;">'+l+"</del>";break;case DIFF_EQUAL:b[g]="<span>"+l+"</span>"}}return b.join("")};
-diff_match_patch.prototype.diff_text1=function(a){for(var b=[],c=0;c<a.length;c++)a[c][0]!==DIFF_INSERT&&(b[c]=a[c][1]);return b.join("")};diff_match_patch.prototype.diff_text2=function(a){for(var b=[],c=0;c<a.length;c++)a[c][0]!==DIFF_DELETE&&(b[c]=a[c][1]);return b.join("")};
-diff_match_patch.prototype.diff_levenshtein=function(a){for(var b=0,c=0,d=0,e=0;e<a.length;e++){var f=a[e][1];switch(a[e][0]){case DIFF_INSERT:c+=f.length;break;case DIFF_DELETE:d+=f.length;break;case DIFF_EQUAL:b+=Math.max(c,d),d=c=0}}return b+=Math.max(c,d)};diff_match_patch.prototype.isHighSurrogate=function(a){a=a.charCodeAt(0);return 55296<=a&&56319>=a};diff_match_patch.prototype.isLowSurrogate=function(a){a=a.charCodeAt(0);return 56320<=a&&57343>=a};
-diff_match_patch.prototype.diff_toDelta=function(a){for(var b=[],c,d=0;d<a.length;d++){var e=a[d],f=e[1][0],g=e[1][e[1].length-1];if(0!==e[1].length&&(g&&this.isHighSurrogate(g)&&(c=g,e[1]=e[1].slice(0,-1)),c&&f&&this.isHighSurrogate(c)&&this.isLowSurrogate(f)&&(e[1]=c+e[1]),DIFF_EQUAL===e[0]&&(c=g),0!==e[1].length))switch(e[0]){case DIFF_INSERT:b.push("+"+encodeURI(e[1]));break;case DIFF_DELETE:b.push("-"+e[1].length);break;case DIFF_EQUAL:b.push("="+e[1].length)}}return b.join("\t").replace(/%20/g,
+return k||l?5:c||d?4:e&&!g&&h?3:g||h?2:e||f?1:0}for(var d=1;d<a.length-1;){if(a[d-1][0]==DIFF_EQUAL&&a[d+1][0]==DIFF_EQUAL){var c=a[d-1][1],e=a[d][1],f=a[d+1][1],g=this.diff_commonSuffix(c,e);if(g){var h=e.substring(e.length-g);c=c.substring(0,c.length-g);e=h+e.substring(0,e.length-g);f=h+f}g=c;h=e;for(var l=f,k=b(c,e)+b(e,f);e.charAt(0)===f.charAt(0);){c+=e.charAt(0);e=e.substring(1)+f.charAt(0);f=f.substring(1);var m=b(c,e)+b(e,f);m>=k&&(k=m,g=c,h=e,l=f)}a[d-1][1]!=g&&(g?a[d-1][1]=g:(a.splice(d-
+1,1),d--),a[d][1]=h,l?a[d+1][1]=l:(a.splice(d+1,1),d--))}d++}};diff_match_patch.nonAlphaNumericRegex_=/[^a-zA-Z0-9]/;diff_match_patch.whitespaceRegex_=/\s/;diff_match_patch.linebreakRegex_=/[\r\n]/;diff_match_patch.blanklineEndRegex_=/\n\r?\n$/;diff_match_patch.blanklineStartRegex_=/^\r?\n\r?\n/;
+diff_match_patch.prototype.diff_cleanupEfficiency=function(a){for(var b=!1,d=[],c=0,e=null,f=0,g=!1,h=!1,l=!1,k=!1;f<a.length;)a[f][0]==DIFF_EQUAL?(a[f][1].length<this.Diff_EditCost&&(l||k)?(d[c++]=f,g=l,h=k,e=a[f][1]):(c=0,e=null),l=k=!1):(a[f][0]==DIFF_DELETE?k=!0:l=!0,e&&(g&&h&&l&&k||e.length<this.Diff_EditCost/2&&3==g+h+l+k)&&(a.splice(d[c-1],0,new diff_match_patch.Diff(DIFF_DELETE,e)),a[d[c-1]+1][0]=DIFF_INSERT,c--,e=null,g&&h?(l=k=!0,c=0):(c--,f=0<c?d[c-1]:-1,l=k=!1),b=!0)),f++;b&&this.diff_cleanupMerge(a)};
+diff_match_patch.prototype.diff_cleanupMerge=function(a){a.push(new diff_match_patch.Diff(DIFF_EQUAL,""));for(var b=0,d=0,c=0,e="",f="",g;b<a.length;)switch(a[b][0]){case DIFF_INSERT:c++;f+=a[b][1];b++;break;case DIFF_DELETE:d++;e+=a[b][1];b++;break;case DIFF_EQUAL:1<d+c?(0!==d&&0!==c&&(g=this.diff_commonPrefix(f,e),0!==g&&(0<b-d-c&&a[b-d-c-1][0]==DIFF_EQUAL?a[b-d-c-1][1]+=f.substring(0,g):(a.splice(0,0,new diff_match_patch.Diff(DIFF_EQUAL,f.substring(0,g))),b++),f=f.substring(g),e=e.substring(g)),
+g=this.diff_commonSuffix(f,e),0!==g&&(a[b][1]=f.substring(f.length-g)+a[b][1],f=f.substring(0,f.length-g),e=e.substring(0,e.length-g))),b-=d+c,a.splice(b,d+c),e.length&&(a.splice(b,0,new diff_match_patch.Diff(DIFF_DELETE,e)),b++),f.length&&(a.splice(b,0,new diff_match_patch.Diff(DIFF_INSERT,f)),b++),b++):0!==b&&a[b-1][0]==DIFF_EQUAL?(a[b-1][1]+=a[b][1],a.splice(b,1)):b++,d=c=0,f=e=""}""===a[a.length-1][1]&&a.pop();d=!1;for(b=1;b<a.length-1;)a[b-1][0]==DIFF_EQUAL&&a[b+1][0]==DIFF_EQUAL&&(a[b][1].substring(a[b][1].length-
+a[b-1][1].length)==a[b-1][1]?(a[b][1]=a[b-1][1]+a[b][1].substring(0,a[b][1].length-a[b-1][1].length),a[b+1][1]=a[b-1][1]+a[b+1][1],a.splice(b-1,1),d=!0):a[b][1].substring(0,a[b+1][1].length)==a[b+1][1]&&(a[b-1][1]+=a[b+1][1],a[b][1]=a[b][1].substring(a[b+1][1].length)+a[b+1][1],a.splice(b+1,1),d=!0)),b++;d&&this.diff_cleanupMerge(a)};
+diff_match_patch.prototype.diff_xIndex=function(a,b){var d=0,c=0,e=0,f=0,g;for(g=0;g<a.length;g++){a[g][0]!==DIFF_INSERT&&(d+=a[g][1].length);a[g][0]!==DIFF_DELETE&&(c+=a[g][1].length);if(d>b)break;e=d;f=c}return a.length!=g&&a[g][0]===DIFF_DELETE?f:f+(b-e)};
+diff_match_patch.prototype.diff_prettyHtml=function(a){for(var b=[],d=/&/g,c=/</g,e=/>/g,f=/\n/g,g=0;g<a.length;g++){var h=a[g][0],l=a[g][1].replace(d,"&amp;").replace(c,"&lt;").replace(e,"&gt;").replace(f,"&para;<br>");switch(h){case DIFF_INSERT:b[g]='<ins style="background:#e6ffe6;">'+l+"</ins>";break;case DIFF_DELETE:b[g]='<del style="background:#ffe6e6;">'+l+"</del>";break;case DIFF_EQUAL:b[g]="<span>"+l+"</span>"}}return b.join("")};
+diff_match_patch.prototype.diff_text1=function(a){for(var b=[],d=0;d<a.length;d++)a[d][0]!==DIFF_INSERT&&(b[d]=a[d][1]);return b.join("")};diff_match_patch.prototype.diff_text2=function(a){for(var b=[],d=0;d<a.length;d++)a[d][0]!==DIFF_DELETE&&(b[d]=a[d][1]);return b.join("")};
+diff_match_patch.prototype.diff_levenshtein=function(a){for(var b=0,d=0,c=0,e=0;e<a.length;e++){var f=a[e][1];switch(a[e][0]){case DIFF_INSERT:d+=f.length;break;case DIFF_DELETE:c+=f.length;break;case DIFF_EQUAL:b+=Math.max(d,c),c=d=0}}return b+=Math.max(d,c)};diff_match_patch.prototype.isHighSurrogate=function(a){a=a.charCodeAt(0);return 55296<=a&&56319>=a};diff_match_patch.prototype.isLowSurrogate=function(a){a=a.charCodeAt(0);return 56320<=a&&57343>=a};
+diff_match_patch.prototype.diff_toDelta=function(a){for(var b=[],d,c=0;c<a.length;c++){var e=a[c],f=e[1][0],g=e[1][e[1].length-1];if(0!==e[1].length&&(g&&this.isHighSurrogate(g)&&(d=g,e[1]=e[1].slice(0,-1)),d&&f&&this.isHighSurrogate(d)&&this.isLowSurrogate(f)&&(e[1]=d+e[1]),DIFF_EQUAL===e[0]&&(d=g),0!==e[1].length))switch(e[0]){case DIFF_INSERT:b.push("+"+encodeURI(e[1]));break;case DIFF_DELETE:b.push("-"+e[1].length);break;case DIFF_EQUAL:b.push("="+e[1].length)}}return b.join("\t").replace(/%20/g,
 " ")};
-diff_match_patch.prototype.diff_fromDelta=function(a,b){for(var c=[],d=0,e=0,f=b.split(/\t/g),g=0;g<f.length;g++){var h=f[g].substring(1);switch(f[g].charAt(0)){case "+":try{c[d++]=new diff_match_patch.Diff(DIFF_INSERT,decodeURI(h))}catch(k){throw Error("Illegal escape in diff_fromDelta: "+h);}break;case "-":case "=":var l=parseInt(h,10);if(isNaN(l)||0>l)throw Error("Invalid number in diff_fromDelta: "+h);h=a.substring(e,e+=l);"="==f[g].charAt(0)?c[d++]=new diff_match_patch.Diff(DIFF_EQUAL,h):c[d++]=
-new diff_match_patch.Diff(DIFF_DELETE,h);break;default:if(f[g])throw Error("Invalid diff operation in diff_fromDelta: "+f[g]);}}if(e!=a.length)throw Error("Delta length ("+e+") does not equal source text length ("+a.length+").");return c};diff_match_patch.prototype.match_main=function(a,b,c){if(null==a||null==b||null==c)throw Error("Null input. (match_main)");c=Math.max(0,Math.min(c,a.length));return a==b?0:a.length?a.substring(c,c+b.length)==b?c:this.match_bitap_(a,b,c):-1};
-diff_match_patch.prototype.match_bitap_=function(a,b,c){function d(a,d){var e=a/b.length,g=Math.abs(c-d);return f.Match_Distance?e+g/f.Match_Distance:g?1:e}if(b.length>this.Match_MaxBits)throw Error("Pattern too long for this browser.");var e=this.match_alphabet_(b),f=this,g=this.Match_Threshold,h=a.indexOf(b,c);-1!=h&&(g=Math.min(d(0,h),g),h=a.lastIndexOf(b,c+b.length),-1!=h&&(g=Math.min(d(0,h),g)));var l=1<<b.length-1;h=-1;for(var k,m,p=b.length+a.length,x,w=0;w<b.length;w++){k=0;for(m=p;k<m;)d(w,
-c+m)<=g?k=m:p=m,m=Math.floor((p-k)/2+k);p=m;k=Math.max(1,c-m+1);var q=Math.min(c+m,a.length)+b.length;m=Array(q+2);for(m[q+1]=(1<<w)-1;q>=k;q--){var t=e[a.charAt(q-1)];m[q]=0===w?(m[q+1]<<1|1)&t:(m[q+1]<<1|1)&t|(x[q+1]|x[q])<<1|1|x[q+1];if(m[q]&l&&(t=d(w,q-1),t<=g))if(g=t,h=q-1,h>c)k=Math.max(1,2*c-h);else break}if(d(w+1,c)>g)break;x=m}return h};
-diff_match_patch.prototype.match_alphabet_=function(a){for(var b={},c=0;c<a.length;c++)b[a.charAt(c)]=0;for(c=0;c<a.length;c++)b[a.charAt(c)]|=1<<a.length-c-1;return b};
-diff_match_patch.prototype.patch_addContext_=function(a,b){if(0!=b.length){if(null===a.start2)throw Error("patch not initialized");for(var c=b.substring(a.start2,a.start2+a.length1),d=0;b.indexOf(c)!=b.lastIndexOf(c)&&c.length<this.Match_MaxBits-this.Patch_Margin-this.Patch_Margin;)d+=this.Patch_Margin,c=b.substring(a.start2-d,a.start2+a.length1+d);d+=this.Patch_Margin;(c=b.substring(a.start2-d,a.start2))&&a.diffs.unshift(new diff_match_patch.Diff(DIFF_EQUAL,c));(d=b.substring(a.start2+a.length1,
-a.start2+a.length1+d))&&a.diffs.push(new diff_match_patch.Diff(DIFF_EQUAL,d));a.start1-=c.length;a.start2-=c.length;a.length1+=c.length+d.length;a.length2+=c.length+d.length}};
-diff_match_patch.prototype.patch_make=function(a,b,c){if("string"==typeof a&&"string"==typeof b&&"undefined"==typeof c){var d=a;b=this.diff_main(d,b,!0);2<b.length&&(this.diff_cleanupSemantic(b),this.diff_cleanupEfficiency(b))}else if(a&&"object"==typeof a&&"undefined"==typeof b&&"undefined"==typeof c)b=a,d=this.diff_text1(b);else if("string"==typeof a&&b&&"object"==typeof b&&"undefined"==typeof c)d=a;else if("string"==typeof a&&"string"==typeof b&&c&&"object"==typeof c)d=a,b=c;else throw Error("Unknown call format to patch_make.");
-if(0===b.length)return[];c=[];a=new diff_match_patch.patch_obj;for(var e=0,f=0,g=0,h=d,l=0;l<b.length;l++){var k=b[l][0],m=b[l][1];e||k===DIFF_EQUAL||(a.start1=f,a.start2=g);switch(k){case DIFF_INSERT:a.diffs[e++]=b[l];a.length2+=m.length;d=d.substring(0,g)+m+d.substring(g);break;case DIFF_DELETE:a.length1+=m.length;a.diffs[e++]=b[l];d=d.substring(0,g)+d.substring(g+m.length);break;case DIFF_EQUAL:m.length<=2*this.Patch_Margin&&e&&b.length!=l+1?(a.diffs[e++]=b[l],a.length1+=m.length,a.length2+=m.length):
-m.length>=2*this.Patch_Margin&&e&&(this.patch_addContext_(a,h),c.push(a),a=new diff_match_patch.patch_obj,e=0,h=d,f=g)}k!==DIFF_INSERT&&(f+=m.length);k!==DIFF_DELETE&&(g+=m.length)}e&&(this.patch_addContext_(a,h),c.push(a));return c};
-diff_match_patch.prototype.patch_deepCopy=function(a){for(var b=[],c=0;c<a.length;c++){var d=a[c],e=new diff_match_patch.patch_obj;e.diffs=[];for(var f=0;f<d.diffs.length;f++)e.diffs[f]=new diff_match_patch.Diff(d.diffs[f][0],d.diffs[f][1]);e.start1=d.start1;e.start2=d.start2;e.length1=d.length1;e.length2=d.length2;b[c]=e}return b};
-diff_match_patch.prototype.patch_apply=function(a,b){if(0==a.length)return[b,[]];a=this.patch_deepCopy(a);var c=this.patch_addPadding(a);b=c+b+c;this.patch_splitMax(a);for(var d=0,e=[],f=0;f<a.length;f++){var g=a[f].start2+d,h=this.diff_text1(a[f].diffs),l=-1;if(h.length>this.Match_MaxBits){var k=this.match_main(b,h.substring(0,this.Match_MaxBits),g);-1!=k&&(l=this.match_main(b,h.substring(h.length-this.Match_MaxBits),g+h.length-this.Match_MaxBits),-1==l||k>=l)&&(k=-1)}else k=this.match_main(b,h,
-g);if(-1==k)e[f]=!1,d-=a[f].length2-a[f].length1;else if(e[f]=!0,d=k-g,g=-1==l?b.substring(k,k+h.length):b.substring(k,l+this.Match_MaxBits),h==g)b=b.substring(0,k)+this.diff_text2(a[f].diffs)+b.substring(k+h.length);else if(g=this.diff_main(h,g,!1),h.length>this.Match_MaxBits&&this.diff_levenshtein(g)/h.length>this.Patch_DeleteThreshold)e[f]=!1;else{this.diff_cleanupSemanticLossless(g);h=0;var m;for(l=0;l<a[f].diffs.length;l++){var p=a[f].diffs[l];p[0]!==DIFF_EQUAL&&(m=this.diff_xIndex(g,h));p[0]===
-DIFF_INSERT?b=b.substring(0,k+m)+p[1]+b.substring(k+m):p[0]===DIFF_DELETE&&(b=b.substring(0,k+m)+b.substring(k+this.diff_xIndex(g,h+p[1].length)));p[0]!==DIFF_DELETE&&(h+=p[1].length)}}}b=b.substring(c.length,b.length-c.length);return[b,e]};
-diff_match_patch.prototype.patch_addPadding=function(a){for(var b=this.Patch_Margin,c="",d=1;d<=b;d++)c+=String.fromCharCode(d);for(d=0;d<a.length;d++)a[d].start1+=b,a[d].start2+=b;d=a[0];var e=d.diffs;if(0==e.length||e[0][0]!=DIFF_EQUAL)e.unshift(new diff_match_patch.Diff(DIFF_EQUAL,c)),d.start1-=b,d.start2-=b,d.length1+=b,d.length2+=b;else if(b>e[0][1].length){var f=b-e[0][1].length;e[0][1]=c.substring(e[0][1].length)+e[0][1];d.start1-=f;d.start2-=f;d.length1+=f;d.length2+=f}d=a[a.length-1];e=d.diffs;
-0==e.length||e[e.length-1][0]!=DIFF_EQUAL?(e.push(new diff_match_patch.Diff(DIFF_EQUAL,c)),d.length1+=b,d.length2+=b):b>e[e.length-1][1].length&&(f=b-e[e.length-1][1].length,e[e.length-1][1]+=c.substring(0,f),d.length1+=f,d.length2+=f);return c};
-diff_match_patch.prototype.patch_splitMax=function(a){for(var b=this.Match_MaxBits,c=0;c<a.length;c++)if(!(a[c].length1<=b)){var d=a[c];a.splice(c--,1);for(var e=d.start1,f=d.start2,g="";0!==d.diffs.length;){var h=new diff_match_patch.patch_obj,l=!0;h.start1=e-g.length;h.start2=f-g.length;""!==g&&(h.length1=h.length2=g.length,h.diffs.push(new diff_match_patch.Diff(DIFF_EQUAL,g)));for(;0!==d.diffs.length&&h.length1<b-this.Patch_Margin;){g=d.diffs[0][0];var k=d.diffs[0][1];g===DIFF_INSERT?(h.length2+=
-k.length,f+=k.length,h.diffs.push(d.diffs.shift()),l=!1):g===DIFF_DELETE&&1==h.diffs.length&&h.diffs[0][0]==DIFF_EQUAL&&k.length>2*b?(h.length1+=k.length,e+=k.length,l=!1,h.diffs.push(new diff_match_patch.Diff(g,k)),d.diffs.shift()):(k=k.substring(0,b-h.length1-this.Patch_Margin),h.length1+=k.length,e+=k.length,g===DIFF_EQUAL?(h.length2+=k.length,f+=k.length):l=!1,h.diffs.push(new diff_match_patch.Diff(g,k)),k==d.diffs[0][1]?d.diffs.shift():d.diffs[0][1]=d.diffs[0][1].substring(k.length))}g=this.diff_text2(h.diffs);
-g=g.substring(g.length-this.Patch_Margin);k=this.diff_text1(d.diffs).substring(0,this.Patch_Margin);""!==k&&(h.length1+=k.length,h.length2+=k.length,0!==h.diffs.length&&h.diffs[h.diffs.length-1][0]===DIFF_EQUAL?h.diffs[h.diffs.length-1][1]+=k:h.diffs.push(new diff_match_patch.Diff(DIFF_EQUAL,k)));l||a.splice(++c,0,h)}}};diff_match_patch.prototype.patch_toText=function(a){for(var b=[],c=0;c<a.length;c++)b[c]=a[c];return b.join("")};
-diff_match_patch.prototype.patch_fromText=function(a){var b=[];if(!a)return b;a=a.split("\n");for(var c=0,d=/^@@ -(\d+),?(\d*) \+(\d+),?(\d*) @@$/;c<a.length;){var e=a[c].match(d);if(!e)throw Error("Invalid patch string: "+a[c]);var f=new diff_match_patch.patch_obj;b.push(f);f.start1=parseInt(e[1],10);""===e[2]?(f.start1--,f.length1=1):"0"==e[2]?f.length1=0:(f.start1--,f.length1=parseInt(e[2],10));f.start2=parseInt(e[3],10);""===e[4]?(f.start2--,f.length2=1):"0"==e[4]?f.length2=0:(f.start2--,f.length2=
-parseInt(e[4],10));for(c++;c<a.length;){e=a[c].charAt(0);try{var g=decodeURI(a[c].substring(1))}catch(h){throw Error("Illegal escape in patch_fromText: "+g);}if("-"==e)f.diffs.push(new diff_match_patch.Diff(DIFF_DELETE,g));else if("+"==e)f.diffs.push(new diff_match_patch.Diff(DIFF_INSERT,g));else if(" "==e)f.diffs.push(new diff_match_patch.Diff(DIFF_EQUAL,g));else if("@"==e)break;else if(""!==e)throw Error('Invalid patch mode "'+e+'" in: '+g);c++}}return b};
+diff_match_patch.prototype.decodeURI=function(a){try{return decodeURI(a)}catch(h){for(var b=0,d="";b<a.length;)if("%"!==a[b])d+=a[b++];else{var c=parseInt(a.substring(b+1,b+3),16);if(0===(c&128))d+=String.fromCharCode(c),b+=3;else{if("%"!==a[b+3])throw new URIError("URI malformed");var e=parseInt(a.substring(b+4,b+6),16);if(128!==(e&192))throw new URIError("URI malformed");e&=63;if(192===(c&224))d+=String.fromCharCode((c&31)<<6|e),b+=6;else{if("%"!==a[b+6])throw new URIError("URI malformed");var f=
+parseInt(a.substring(b+7,b+9),16);if(128!==(f&192))throw new URIError("URI malformed");f&=63;if(224===(c&240))d+=String.fromCharCode((c&15)<<12|e<<6|f),b+=9;else{if("%"!==a[b+9])throw new URIError("URI malformed");var g=parseInt(a.substring(b+10,b+12),16);if(128!==(g&192))throw new URIError("URI malformed");g&=63;if(240===(c&248)&&(c=(c&7)<<18|e<<12|f<<6|g,65536<=c&&1114111>=c)){d+=String.fromCharCode((c&65535)>>>10&1023|55296);d+=String.fromCharCode(56320|c&1023);b+=12;continue}throw new URIError("URI malformed");
+}}}}return d}};
+diff_match_patch.prototype.diff_fromDelta=function(a,b){for(var d=[],c=0,e=0,f=b.split(/\t/g),g=0;g<f.length;g++){var h=f[g].substring(1);switch(f[g].charAt(0)){case "+":try{d[c++]=new diff_match_patch.Diff(DIFF_INSERT,this.decodeURI(h))}catch(k){throw Error("Illegal escape in diff_fromDelta: "+h);}break;case "-":case "=":var l=parseInt(h,10);if(isNaN(l)||0>l)throw Error("Invalid number in diff_fromDelta: "+h);h=a.substring(e,e+=l);"="==f[g].charAt(0)?d[c++]=new diff_match_patch.Diff(DIFF_EQUAL,h):
+d[c++]=new diff_match_patch.Diff(DIFF_DELETE,h);break;default:if(f[g])throw Error("Invalid diff operation in diff_fromDelta: "+f[g]);}}if(e!=a.length)throw Error("Delta length ("+e+") does not equal source text length ("+a.length+").");return d};diff_match_patch.prototype.match_main=function(a,b,d){if(null==a||null==b||null==d)throw Error("Null input. (match_main)");d=Math.max(0,Math.min(d,a.length));return a==b?0:a.length?a.substring(d,d+b.length)==b?d:this.match_bitap_(a,b,d):-1};
+diff_match_patch.prototype.match_bitap_=function(a,b,d){function c(a,c){var e=a/b.length,g=Math.abs(d-c);return f.Match_Distance?e+g/f.Match_Distance:g?1:e}if(b.length>this.Match_MaxBits)throw Error("Pattern too long for this browser.");var e=this.match_alphabet_(b),f=this,g=this.Match_Threshold,h=a.indexOf(b,d);-1!=h&&(g=Math.min(c(0,h),g),h=a.lastIndexOf(b,d+b.length),-1!=h&&(g=Math.min(c(0,h),g)));var l=1<<b.length-1;h=-1;for(var k,m,p=b.length+a.length,x,w=0;w<b.length;w++){k=0;for(m=p;k<m;)c(w,
+d+m)<=g?k=m:p=m,m=Math.floor((p-k)/2+k);p=m;k=Math.max(1,d-m+1);var q=Math.min(d+m,a.length)+b.length;m=Array(q+2);for(m[q+1]=(1<<w)-1;q>=k;q--){var t=e[a.charAt(q-1)];m[q]=0===w?(m[q+1]<<1|1)&t:(m[q+1]<<1|1)&t|(x[q+1]|x[q])<<1|1|x[q+1];if(m[q]&l&&(t=c(w,q-1),t<=g))if(g=t,h=q-1,h>d)k=Math.max(1,2*d-h);else break}if(c(w+1,d)>g)break;x=m}return h};
+diff_match_patch.prototype.match_alphabet_=function(a){for(var b={},d=0;d<a.length;d++)b[a.charAt(d)]=0;for(d=0;d<a.length;d++)b[a.charAt(d)]|=1<<a.length-d-1;return b};
+diff_match_patch.prototype.patch_addContext_=function(a,b){if(0!=b.length){if(null===a.start2)throw Error("patch not initialized");for(var d=b.substring(a.start2,a.start2+a.length1),c=0;b.indexOf(d)!=b.lastIndexOf(d)&&d.length<this.Match_MaxBits-this.Patch_Margin-this.Patch_Margin;)c+=this.Patch_Margin,d=b.substring(a.start2-c,a.start2+a.length1+c);c+=this.Patch_Margin;(d=b.substring(a.start2-c,a.start2))&&a.diffs.unshift(new diff_match_patch.Diff(DIFF_EQUAL,d));(c=b.substring(a.start2+a.length1,
+a.start2+a.length1+c))&&a.diffs.push(new diff_match_patch.Diff(DIFF_EQUAL,c));a.start1-=d.length;a.start2-=d.length;a.length1+=d.length+c.length;a.length2+=d.length+c.length}};
+diff_match_patch.prototype.patch_make=function(a,b,d){if("string"==typeof a&&"string"==typeof b&&"undefined"==typeof d){var c=a;b=this.diff_main(c,b,!0);2<b.length&&(this.diff_cleanupSemantic(b),this.diff_cleanupEfficiency(b))}else if(a&&"object"==typeof a&&"undefined"==typeof b&&"undefined"==typeof d)b=a,c=this.diff_text1(b);else if("string"==typeof a&&b&&"object"==typeof b&&"undefined"==typeof d)c=a;else if("string"==typeof a&&"string"==typeof b&&d&&"object"==typeof d)c=a,b=d;else throw Error("Unknown call format to patch_make.");
+if(0===b.length)return[];d=[];a=new diff_match_patch.patch_obj;for(var e=0,f=0,g=0,h=c,l=0;l<b.length;l++){var k=b[l][0],m=b[l][1];e||k===DIFF_EQUAL||(a.start1=f,a.start2=g);switch(k){case DIFF_INSERT:a.diffs[e++]=b[l];a.length2+=m.length;c=c.substring(0,g)+m+c.substring(g);break;case DIFF_DELETE:a.length1+=m.length;a.diffs[e++]=b[l];c=c.substring(0,g)+c.substring(g+m.length);break;case DIFF_EQUAL:m.length<=2*this.Patch_Margin&&e&&b.length!=l+1?(a.diffs[e++]=b[l],a.length1+=m.length,a.length2+=m.length):
+m.length>=2*this.Patch_Margin&&e&&(this.patch_addContext_(a,h),d.push(a),a=new diff_match_patch.patch_obj,e=0,h=c,f=g)}k!==DIFF_INSERT&&(f+=m.length);k!==DIFF_DELETE&&(g+=m.length)}e&&(this.patch_addContext_(a,h),d.push(a));return d};
+diff_match_patch.prototype.patch_deepCopy=function(a){for(var b=[],d=0;d<a.length;d++){var c=a[d],e=new diff_match_patch.patch_obj;e.diffs=[];for(var f=0;f<c.diffs.length;f++)e.diffs[f]=new diff_match_patch.Diff(c.diffs[f][0],c.diffs[f][1]);e.start1=c.start1;e.start2=c.start2;e.length1=c.length1;e.length2=c.length2;b[d]=e}return b};
+diff_match_patch.prototype.patch_apply=function(a,b){if(0==a.length)return[b,[]];a=this.patch_deepCopy(a);var d=this.patch_addPadding(a);b=d+b+d;this.patch_splitMax(a);for(var c=0,e=[],f=0;f<a.length;f++){var g=a[f].start2+c,h=this.diff_text1(a[f].diffs),l=-1;if(h.length>this.Match_MaxBits){var k=this.match_main(b,h.substring(0,this.Match_MaxBits),g);-1!=k&&(l=this.match_main(b,h.substring(h.length-this.Match_MaxBits),g+h.length-this.Match_MaxBits),-1==l||k>=l)&&(k=-1)}else k=this.match_main(b,h,
+g);if(-1==k)e[f]=!1,c-=a[f].length2-a[f].length1;else if(e[f]=!0,c=k-g,g=-1==l?b.substring(k,k+h.length):b.substring(k,l+this.Match_MaxBits),h==g)b=b.substring(0,k)+this.diff_text2(a[f].diffs)+b.substring(k+h.length);else if(g=this.diff_main(h,g,!1),h.length>this.Match_MaxBits&&this.diff_levenshtein(g)/h.length>this.Patch_DeleteThreshold)e[f]=!1;else{this.diff_cleanupSemanticLossless(g);h=0;var m;for(l=0;l<a[f].diffs.length;l++){var p=a[f].diffs[l];p[0]!==DIFF_EQUAL&&(m=this.diff_xIndex(g,h));p[0]===
+DIFF_INSERT?b=b.substring(0,k+m)+p[1]+b.substring(k+m):p[0]===DIFF_DELETE&&(b=b.substring(0,k+m)+b.substring(k+this.diff_xIndex(g,h+p[1].length)));p[0]!==DIFF_DELETE&&(h+=p[1].length)}}}b=b.substring(d.length,b.length-d.length);return[b,e]};
+diff_match_patch.prototype.patch_addPadding=function(a){for(var b=this.Patch_Margin,d="",c=1;c<=b;c++)d+=String.fromCharCode(c);for(c=0;c<a.length;c++)a[c].start1+=b,a[c].start2+=b;c=a[0];var e=c.diffs;if(0==e.length||e[0][0]!=DIFF_EQUAL)e.unshift(new diff_match_patch.Diff(DIFF_EQUAL,d)),c.start1-=b,c.start2-=b,c.length1+=b,c.length2+=b;else if(b>e[0][1].length){var f=b-e[0][1].length;e[0][1]=d.substring(e[0][1].length)+e[0][1];c.start1-=f;c.start2-=f;c.length1+=f;c.length2+=f}c=a[a.length-1];e=c.diffs;
+0==e.length||e[e.length-1][0]!=DIFF_EQUAL?(e.push(new diff_match_patch.Diff(DIFF_EQUAL,d)),c.length1+=b,c.length2+=b):b>e[e.length-1][1].length&&(f=b-e[e.length-1][1].length,e[e.length-1][1]+=d.substring(0,f),c.length1+=f,c.length2+=f);return d};
+diff_match_patch.prototype.patch_splitMax=function(a){for(var b=this.Match_MaxBits,d=0;d<a.length;d++)if(!(a[d].length1<=b)){var c=a[d];a.splice(d--,1);for(var e=c.start1,f=c.start2,g="";0!==c.diffs.length;){var h=new diff_match_patch.patch_obj,l=!0;h.start1=e-g.length;h.start2=f-g.length;""!==g&&(h.length1=h.length2=g.length,h.diffs.push(new diff_match_patch.Diff(DIFF_EQUAL,g)));for(;0!==c.diffs.length&&h.length1<b-this.Patch_Margin;){g=c.diffs[0][0];var k=c.diffs[0][1];g===DIFF_INSERT?(h.length2+=
+k.length,f+=k.length,h.diffs.push(c.diffs.shift()),l=!1):g===DIFF_DELETE&&1==h.diffs.length&&h.diffs[0][0]==DIFF_EQUAL&&k.length>2*b?(h.length1+=k.length,e+=k.length,l=!1,h.diffs.push(new diff_match_patch.Diff(g,k)),c.diffs.shift()):(k=k.substring(0,b-h.length1-this.Patch_Margin),h.length1+=k.length,e+=k.length,g===DIFF_EQUAL?(h.length2+=k.length,f+=k.length):l=!1,h.diffs.push(new diff_match_patch.Diff(g,k)),k==c.diffs[0][1]?c.diffs.shift():c.diffs[0][1]=c.diffs[0][1].substring(k.length))}g=this.diff_text2(h.diffs);
+g=g.substring(g.length-this.Patch_Margin);k=this.diff_text1(c.diffs).substring(0,this.Patch_Margin);""!==k&&(h.length1+=k.length,h.length2+=k.length,0!==h.diffs.length&&h.diffs[h.diffs.length-1][0]===DIFF_EQUAL?h.diffs[h.diffs.length-1][1]+=k:h.diffs.push(new diff_match_patch.Diff(DIFF_EQUAL,k)));l||a.splice(++d,0,h)}}};diff_match_patch.prototype.patch_toText=function(a){for(var b=[],d=0;d<a.length;d++)b[d]=a[d];return b.join("")};
+diff_match_patch.prototype.patch_fromText=function(a){var b=[];if(!a)return b;a=a.split("\n");for(var d=0,c=/^@@ -(\d+),?(\d*) \+(\d+),?(\d*) @@$/;d<a.length;){var e=a[d].match(c);if(!e)throw Error("Invalid patch string: "+a[d]);var f=new diff_match_patch.patch_obj;b.push(f);f.start1=parseInt(e[1],10);""===e[2]?(f.start1--,f.length1=1):"0"==e[2]?f.length1=0:(f.start1--,f.length1=parseInt(e[2],10));f.start2=parseInt(e[3],10);""===e[4]?(f.start2--,f.length2=1):"0"==e[4]?f.length2=0:(f.start2--,f.length2=
+parseInt(e[4],10));for(d++;d<a.length;){e=a[d].charAt(0);try{var g=decodeURI(a[d].substring(1))}catch(h){throw Error("Illegal escape in patch_fromText: "+g);}if("-"==e)f.diffs.push(new diff_match_patch.Diff(DIFF_DELETE,g));else if("+"==e)f.diffs.push(new diff_match_patch.Diff(DIFF_INSERT,g));else if(" "==e)f.diffs.push(new diff_match_patch.Diff(DIFF_EQUAL,g));else if("@"==e)break;else if(""!==e)throw Error('Invalid patch mode "'+e+'" in: '+g);d++}}return b};
 diff_match_patch.patch_obj=function(){this.diffs=[];this.start2=this.start1=null;this.length2=this.length1=0};
-diff_match_patch.patch_obj.prototype.toString=function(){for(var a=["@@ -"+(0===this.length1?this.start1+",0":1==this.length1?this.start1+1:this.start1+1+","+this.length1)+" +"+(0===this.length2?this.start2+",0":1==this.length2?this.start2+1:this.start2+1+","+this.length2)+" @@\n"],b,c=0;c<this.diffs.length;c++){switch(this.diffs[c][0]){case DIFF_INSERT:b="+";break;case DIFF_DELETE:b="-";break;case DIFF_EQUAL:b=" "}a[c+1]=b+encodeURI(this.diffs[c][1])+"\n"}return a.join("").replace(/%20/g," ")};
+diff_match_patch.patch_obj.prototype.toString=function(){for(var a=["@@ -"+(0===this.length1?this.start1+",0":1==this.length1?this.start1+1:this.start1+1+","+this.length1)+" +"+(0===this.length2?this.start2+",0":1==this.length2?this.start2+1:this.start2+1+","+this.length2)+" @@\n"],b,d=0;d<this.diffs.length;d++){switch(this.diffs[d][0]){case DIFF_INSERT:b="+";break;case DIFF_DELETE:b="-";break;case DIFF_EQUAL:b=" "}a[d+1]=b+encodeURI(this.diffs[d][1])+"\n"}return a.join("").replace(/%20/g," ")};
 this.diff_match_patch=diff_match_patch;this.DIFF_DELETE=DIFF_DELETE;this.DIFF_INSERT=DIFF_INSERT;this.DIFF_EQUAL=DIFF_EQUAL;
\ No newline at end of file
diff --git a/javascript/diff_match_patch_uncompressed.js b/javascript/diff_match_patch_uncompressed.js
index 48c40cb..0d2821d 100644
--- a/javascript/diff_match_patch_uncompressed.js
+++ b/javascript/diff_match_patch_uncompressed.js
@@ -1406,6 +1406,100 @@ diff_match_patch.prototype.diff_toDelta = function(diffs) {
   return text.join('\t').replace(/%20/g, ' ');
 };
 
+/**
+ * Decode URI-encoded string but allow for encoded surrogate halves
+ * 
+ * diff_match_patch needs this relaxation of the requirements because
+ * not all libraries and versions produce valid URI strings in toDelta
+ * and we don't want to crash this code when the input is valid input
+ * but at the same time invalid utf-8
+ * 
+ * @example: decodeURI( 'abcd%3A %F0%9F%85%B0' ) = 'abcd: \ud83c\udd70'
+ * @example: decodeURI( 'abcd%3A %ED%A0%BC' ) = 'abcd: \ud83c'
+ * 
+ * @cite: @mathiasbynens utf8.js at https://github.com/mathiasbynens/utf8.js
+ * 
+ * @param {String} text input string encoded by encodeURI() or equivalent
+ * @return {String}
+ */
+diff_match_patch.prototype.decodeURI = function(text) {
+  try {
+    return decodeURI(text);
+  } catch ( e ) {
+    var i = 0;
+    var decoded = '';
+
+    while (i < text.length) {
+      if ( text[i] !== '%' ) {
+        decoded += text[i++];
+        continue;
+      }
+
+      // start a percent-sequence
+      var byte1 = parseInt(text.substring(i + 1, i + 3), 16);
+      
+      if ((byte1 & 0x80) === 0) {
+        decoded += String.fromCharCode(byte1);
+        i += 3;
+        continue;
+      }
+
+      if ('%' !== text[i + 3]) {
+        throw new URIError('URI malformed');
+      }
+
+      var byte2 = parseInt(text.substring(i + 4, i + 6), 16);
+      if ((byte2 & 0xC0) !== 0x80) {
+        throw new URIError('URI malformed');
+      }
+      byte2 = byte2 & 0x3F;
+      if ((byte1 & 0xE0) === 0xC0) {
+        decoded += String.fromCharCode(((byte1 & 0x1F) << 6) | byte2);
+        i += 6;
+        continue;
+      }
+
+      if ('%' !== text[i + 6]) {
+        throw new URIError('URI malformed');
+      }
+
+      var byte3 = parseInt(text.substring(i + 7, i + 9), 16);
+      if ((byte3 & 0xC0) !== 0x80) {
+        throw new URIError('URI malformed');
+      }
+      byte3 = byte3 & 0x3F;
+      if ((byte1 & 0xF0) === 0xE0) {
+        // unpaired surrogate are fine here
+        decoded += String.fromCharCode(((byte1 & 0x0F) << 12) | (byte2 << 6) | byte3);
+        i += 9;
+        continue;
+      }
+
+      if ('%' !== text[i + 9]) {
+        throw new URIError('URI malformed');
+      }
+
+      var byte4 = parseInt(text.substring(i + 10, i + 12), 16);
+      if ((byte4 & 0xC0) !== 0x80) {
+        throw new URIError('URI malformed');
+      }
+      byte4 = byte4 & 0x3F;
+      if ((byte1 & 0xF8) === 0xF0) {
+        var codePoint = ((byte1 & 0x07) << 0x12) | (byte2 << 0x0C) | (byte3 << 0x06) | byte4;
+        if (codePoint >= 0x010000 && codePoint <= 0x10FFFF) {
+          decoded += String.fromCharCode((codePoint & 0xFFFF) >>> 10 & 0x3FF | 0xD800);
+          decoded += String.fromCharCode(0xDC00 | (codePoint & 0xFFFF) & 0x3FF);
+          i += 12;
+          continue;
+        }
+      }
+
+      throw new URIError('URI malformed');
+    }
+
+    return decoded;
+  }
+};
 
 /**
  * Given the original text1, and an encoded string which describes the
@@ -1428,7 +1522,7 @@ diff_match_patch.prototype.diff_fromDelta = function(text1, delta) {
       case '+':
         try {
           diffs[diffsLength++] =
-              new diff_match_patch.Diff(DIFF_INSERT, decodeURI(param));
+              new diff_match_patch.Diff(DIFF_INSERT, this.decodeURI(param));
         } catch (ex) {
           // Malformed URI sequence.
           throw new Error('Illegal escape in diff_fromDelta: ' + param);
diff --git a/javascript/tests/diff_match_patch_test.js b/javascript/tests/diff_match_patch_test.js
index 4283f9d..4222ce6 100644
--- a/javascript/tests/diff_match_patch_test.js
+++ b/javascript/tests/diff_match_patch_test.js
@@ -580,12 +580,20 @@ function testDiffDelta() {
 
   // Empty diff groups
   assertEquivalent(
-    JSON.stringify(dmp.diff_toDelta([[DIFF_EQUAL, 'abcdef'], [DIFF_DELETE, ''], [DIFF_INSERT, 'ghijk']])),
-    JSON.stringify(dmp.diff_toDelta([[DIFF_EQUAL, 'abcdef'], [DIFF_INSERT, 'ghijk']])),
+    dmp.diff_toDelta([[DIFF_EQUAL, 'abcdef'], [DIFF_DELETE, ''], [DIFF_INSERT, 'ghijk']]),
+    dmp.diff_toDelta([[DIFF_EQUAL, 'abcdef'], [DIFF_INSERT, 'ghijk']]),
   );
 
-  // Invalid UTF8 but valid surrogate pairs
-  
+  // Different versions of the library may have created deltas with
+  // half of a surrogate pair encoded as if it were valid UTF-8
+  try {
+    assertEquivalent(
+      dmp.diff_toDelta(dmp.diff_fromDelta('\ud83c\udd70', '-2\t+%F0%9F%85%B1')),
+      dmp.diff_toDelta(dmp.diff_fromDelta('\ud83c\udd70', '=1\t-1\t+%ED%B5%B1'))
+    );
+  } catch ( e ) {
+    assertEquals('Decode UTF8-encoded surrogate half', 'crashed');
+  }
 
   // Verify pool of unchanged characters.
   diffs = [[DIFF_INSERT, 'A-Z a-z 0-9 - _ . ! ~ * \' ( ) ; / ? : @ & = + $ , # ']];

From 7e5a643dec0d84bfd531413bec144331067273d0 Mon Sep 17 00:00:00 2001
From: Dennis Snell <dennis.snell@automattic.com>
Date: Fri, 13 Dec 2019 00:56:49 -0700
Subject: [PATCH 15/34] Port the improvements to Java

---
 .../neil/plaintext/diff_match_patch.java      | 89 +++++++++++++++++--
 .../neil/plaintext/diff_match_patch_test.java | 32 +++++++
 2 files changed, 116 insertions(+), 5 deletions(-)

diff --git a/java/src/name/fraser/neil/plaintext/diff_match_patch.java b/java/src/name/fraser/neil/plaintext/diff_match_patch.java
index d5ecb2c..fe00bc1 100644
--- a/java/src/name/fraser/neil/plaintext/diff_match_patch.java
+++ b/java/src/name/fraser/neil/plaintext/diff_match_patch.java
@@ -1433,6 +1433,9 @@ public String diff_toDelta(List<Diff> diffs) {
     char lastEnd = 0;
     boolean isFirst = true;
     for (Diff aDiff : diffs) {
+      if (aDiff.text.isEmpty()) {
+        continue;
+      }
 
       char thisTop = aDiff.text.charAt(0);
       char thisEnd = aDiff.text.charAt(aDiff.text.length() - 1);
@@ -1446,7 +1449,11 @@ public String diff_toDelta(List<Diff> diffs) {
       }
 
       isFirst = false;
-      lastEnd = thisEnd;
+
+      if (aDiff.operation == Operation.EQUAL) {
+        lastEnd = thisEnd;
+      }
+
       if ( aDiff.text.isEmpty() ) {
         continue;
       }
@@ -1478,6 +1485,81 @@ public String diff_toDelta(List<Diff> diffs) {
     return delta;
   }
 
+  private String decodeURI(String text) throws IllegalArgumentException {
+    int i = 0;
+    StringBuffer decoded = new StringBuffer("");
+
+    while (i < text.length()) {
+      if ( text.charAt(i) != '%' ) {
+        decoded.append(text.charAt(i++));
+        continue;
+      }
+
+      // start a percent-sequence
+      int byte1 = Integer.parseInt(text.substring(i + 1, i + 3), 16);
+      
+      if ((byte1 & 0x80) == 0) {
+        decoded.append(Character.toChars(byte1));
+        i += 3;
+        continue;
+      }
+
+      if ( text.charAt(i + 3) != '%') {
+        throw new IllegalArgumentException();
+      }
+
+      int byte2 = Integer.parseInt(text.substring(i + 4, i + 6), 16);
+      if ((byte2 & 0xC0) != 0x80) {
+        throw new IllegalArgumentException();
+      }
+      byte2 = byte2 & 0x3F;
+      if ((byte1 & 0xE0) == 0xC0) {
+        decoded.append(Character.toChars(((byte1 & 0x1F) << 6) | byte2));
+        i += 6;
+        continue;
+      }
+
+      if (text.charAt(i + 6) != '%') {
+        throw new IllegalArgumentException();
+      }
+
+      int byte3 = Integer.parseInt(text.substring(i + 7, i + 9), 16);
+      if ((byte3 & 0xC0) != 0x80) {
+        throw new IllegalArgumentException();
+      }
+      byte3 = byte3 & 0x3F;
+      if ((byte1 & 0xF0) == 0xE0) {
+        // unpaired surrogate are fine here
+        decoded.append(Character.toChars(((byte1 & 0x0F) << 12) | (byte2 << 6) | byte3));
+        i += 9;
+        continue;
+      }
+
+      if (text.charAt(i + 9) != '%') {
+        throw new IllegalArgumentException();
+      }
+
+      int byte4 = Integer.parseInt(text.substring(i + 10, i + 12), 16);
+      if ((byte4 & 0xC0) != 0x80) {
+        throw new IllegalArgumentException();
+      }
+      byte4 = byte4 & 0x3F;
+      if ((byte1 & 0xF8) == 0xF0) {
+        int codePoint = ((byte1 & 0x07) << 0x12) | (byte2 << 0x0C) | (byte3 << 0x06) | byte4;
+        if (codePoint >= 0x010000 && codePoint <= 0x10FFFF) {
+          decoded.append(Character.toChars((codePoint & 0xFFFF) >>> 10 & 0x3FF | 0xD800));
+          decoded.append(Character.toChars(0xDC00 | (codePoint & 0xFFFF) & 0x3FF));
+          i += 12;
+          continue;
+        }
+      }
+
+      throw new IllegalArgumentException();
+    }
+
+    return decoded.toString();
+  }
+
   /**
    * Given the original text1, and an encoded string which describes the
    * operations required to transform text1 into text2, compute the full diff.
@@ -1504,10 +1586,7 @@ public LinkedList<Diff> diff_fromDelta(String text1, String delta)
         // decode would change all "+" to " "
         param = param.replace("+", "%2B");
         try {
-          param = URLDecoder.decode(param, "UTF-8");
-        } catch (UnsupportedEncodingException e) {
-          // Not likely on modern system.
-          throw new Error("This system does not support UTF-8.", e);
+          param = this.decodeURI(param);
         } catch (IllegalArgumentException e) {
           // Malformed URI sequence.
           throw new IllegalArgumentException(
diff --git a/java/tests/name/fraser/neil/plaintext/diff_match_patch_test.java b/java/tests/name/fraser/neil/plaintext/diff_match_patch_test.java
index aef98ce..5be10f1 100644
--- a/java/tests/name/fraser/neil/plaintext/diff_match_patch_test.java
+++ b/java/tests/name/fraser/neil/plaintext/diff_match_patch_test.java
@@ -428,6 +428,38 @@ public static void testDiffDelta() {
     delta = dmp.diff_toDelta(diffs);
     assertEquals("diff_toDelta: Surrogate Pairs.", "=2\t+%F0%9F%99%8C\t=2", delta);
 
+    assertEquals(
+      "diff_toDelta: insert surrogate pair between similar high surrogates",
+      dmp.diff_toDelta(diffList(new Diff(EQUAL, "\ud83c\udd70"), new Diff(INSERT, "\ud83c\udd70"), new Diff(EQUAL, "\ud83c\udd71"))),
+      dmp.diff_toDelta(diffList(new Diff(EQUAL, "\ud83c\udd70\ud83c"), new Diff(INSERT, "\udd70\ud83c"), new Diff(EQUAL, "\udd71")))
+    );
+
+    assertEquals(
+      "diff_toDelta: swap surrogate pairs delete/insert",
+      dmp.diff_toDelta(diffList(new Diff(DELETE, "\ud83c\udd70"), new Diff(INSERT, "\ud83c\udd71"))),
+      dmp.diff_toDelta(diffList(new Diff(EQUAL, "\ud83c"), new Diff(DELETE, "\udd70"), new Diff(INSERT, "\udd71")))
+    );
+
+    assertEquals(
+      "diff_toDelta: swap surrogate pairs insert/delete",
+      dmp.diff_toDelta(diffList(new Diff(INSERT, "\ud83c\udd70"), new Diff(DELETE, "\ud83c\udd71"))),
+      dmp.diff_toDelta(diffList(new Diff(EQUAL, "\ud83c"), new Diff(INSERT, "\udd70"), new Diff(DELETE, "\udd71")))
+    );
+
+    assertEquals(
+      "diff_toDelta: empty diff groups",
+      dmp.diff_toDelta(diffList(new Diff(EQUAL, "abcdef"), new Diff(DELETE, ""), new Diff(INSERT, "ghijk"))),
+      dmp.diff_toDelta(diffList(new Diff(EQUAL, "abcdef"), new Diff(INSERT, "ghijk")))
+    );
+
+    // Different versions of the library may have created deltas with
+    // half of a surrogate pair encoded as if it were valid UTF-8
+    assertEquals(
+      "diff_toDelta: surrogate half encoded as UTF8",
+      dmp.diff_toDelta(dmp.diff_fromDelta("\ud83c\udd70", "-2\t+%F0%9F%85%B1")),
+      dmp.diff_toDelta(dmp.diff_fromDelta("\ud83c\udd70", "=1\t-1\t+%ED%B5%B1"))
+    );
+
     // Verify pool of unchanged characters.
     diffs = diffList(new Diff(INSERT, "A-Z a-z 0-9 - _ . ! ~ * ' ( ) ; / ? : @ & = + $ , # "));
     String text2 = dmp.diff_text2(diffs);

From 42bc948729868067b8f90fe2a0b8671de9c9d2b8 Mon Sep 17 00:00:00 2001
From: Dennis Snell <dennis.snell@automattic.com>
Date: Fri, 13 Dec 2019 01:56:56 -0700
Subject: [PATCH 16/34] Java: Use lookup vs. parseInt() for URI decoding

---
 .../neil/plaintext/diff_match_patch.java      | 39 ++++++++++++++-----
 1 file changed, 29 insertions(+), 10 deletions(-)

diff --git a/java/src/name/fraser/neil/plaintext/diff_match_patch.java b/java/src/name/fraser/neil/plaintext/diff_match_patch.java
index fe00bc1..2d52098 100644
--- a/java/src/name/fraser/neil/plaintext/diff_match_patch.java
+++ b/java/src/name/fraser/neil/plaintext/diff_match_patch.java
@@ -1485,19 +1485,41 @@ public String diff_toDelta(List<Diff> diffs) {
     return delta;
   }
 
+  private int digit16(char b) throws IllegalArgumentException {
+    switch (b) {
+      case '0': return 0;
+      case '1': return 1;
+      case '2': return 2;
+      case '3': return 3;
+      case '4': return 4;
+      case '5': return 5;
+      case '6': return 6;
+      case '7': return 7;
+      case '8': return 8;
+      case '9': return 9;
+      case 'A': case 'a': return 10;
+      case 'B': case 'b': return 11;
+      case 'C': case 'c': return 12;
+      case 'D': case 'd': return 13;
+      case 'E': case 'e': return 14;
+      case 'F': case 'f': return 15;
+      default:
+        throw new IllegalArgumentException();
+    }
+  }
+
   private String decodeURI(String text) throws IllegalArgumentException {
     int i = 0;
     StringBuffer decoded = new StringBuffer("");
 
     while (i < text.length()) {
-      if ( text.charAt(i) != '%' ) {
+      if (text.charAt(i) != '%') {
         decoded.append(text.charAt(i++));
         continue;
       }
 
       // start a percent-sequence
-      int byte1 = Integer.parseInt(text.substring(i + 1, i + 3), 16);
-      
+      int byte1 = (digit16(text.charAt(i + 1)) << 4) + digit16(text.charAt(i + 2));
       if ((byte1 & 0x80) == 0) {
         decoded.append(Character.toChars(byte1));
         i += 3;
@@ -1508,7 +1530,7 @@ private String decodeURI(String text) throws IllegalArgumentException {
         throw new IllegalArgumentException();
       }
 
-      int byte2 = Integer.parseInt(text.substring(i + 4, i + 6), 16);
+      int byte2 = (digit16(text.charAt(i + 4)) << 4) + digit16(text.charAt(i + 5));
       if ((byte2 & 0xC0) != 0x80) {
         throw new IllegalArgumentException();
       }
@@ -1523,7 +1545,7 @@ private String decodeURI(String text) throws IllegalArgumentException {
         throw new IllegalArgumentException();
       }
 
-      int byte3 = Integer.parseInt(text.substring(i + 7, i + 9), 16);
+      int byte3 = (digit16(text.charAt(i + 7)) << 4) + digit16(text.charAt(i + 8));
       if ((byte3 & 0xC0) != 0x80) {
         throw new IllegalArgumentException();
       }
@@ -1539,7 +1561,7 @@ private String decodeURI(String text) throws IllegalArgumentException {
         throw new IllegalArgumentException();
       }
 
-      int byte4 = Integer.parseInt(text.substring(i + 10, i + 12), 16);
+      int byte4 = (digit16(text.charAt(i + 10)) << 4) + digit16(text.charAt(i + 11));
       if ((byte4 & 0xC0) != 0x80) {
         throw new IllegalArgumentException();
       }
@@ -2369,10 +2391,7 @@ public List<Patch> patch_fromText(String textline)
         line = text.getFirst().substring(1);
         line = line.replace("+", "%2B");  // decode would change all "+" to " "
         try {
-          line = URLDecoder.decode(line, "UTF-8");
-        } catch (UnsupportedEncodingException e) {
-          // Not likely on modern system.
-          throw new Error("This system does not support UTF-8.", e);
+          line = this.decodeURI(line);
         } catch (IllegalArgumentException e) {
           // Malformed URI sequence.
           throw new IllegalArgumentException(

From 7eeca252642c9629d570dcd99742b61b859443e6 Mon Sep 17 00:00:00 2001
From: Dennis Snell <dennis.snell@automattic.com>
Date: Mon, 16 Dec 2019 12:38:28 -0700
Subject: [PATCH 17/34] Add more test cases, update code and decoder

---
 .../neil/plaintext/diff_match_patch.java      |  5 +---
 javascript/diff_match_patch_uncompressed.js   |  6 ----
 javascript/tests/diff_match_patch_test.js     | 29 ++++++++++++++++++-
 3 files changed, 29 insertions(+), 11 deletions(-)

diff --git a/java/src/name/fraser/neil/plaintext/diff_match_patch.java b/java/src/name/fraser/neil/plaintext/diff_match_patch.java
index 2d52098..9f3f71e 100644
--- a/java/src/name/fraser/neil/plaintext/diff_match_patch.java
+++ b/java/src/name/fraser/neil/plaintext/diff_match_patch.java
@@ -1441,6 +1441,7 @@ public String diff_toDelta(List<Diff> diffs) {
       char thisEnd = aDiff.text.charAt(aDiff.text.length() - 1);
 
       if (Character.isHighSurrogate(thisEnd)) {
+        lastEnd = thisEnd;
         aDiff.text = aDiff.text.substring(0, aDiff.text.length() - 1);
       }
 
@@ -1450,10 +1451,6 @@ public String diff_toDelta(List<Diff> diffs) {
 
       isFirst = false;
 
-      if (aDiff.operation == Operation.EQUAL) {
-        lastEnd = thisEnd;
-      }
-
       if ( aDiff.text.isEmpty() ) {
         continue;
       }
diff --git a/javascript/diff_match_patch_uncompressed.js b/javascript/diff_match_patch_uncompressed.js
index 0d2821d..b15c26c 100644
--- a/javascript/diff_match_patch_uncompressed.js
+++ b/javascript/diff_match_patch_uncompressed.js
@@ -1381,12 +1381,6 @@ diff_match_patch.prototype.diff_toDelta = function(diffs) {
       thisDiff[1] = lastEnd + thisDiff[1];
     }
 
-    // we have to carry the surrogate half through
-    // any successive insert/delete edits
-    if (DIFF_EQUAL === thisDiff[0]) {
-      lastEnd = thisEnd;
-    }
-
     if (0 === thisDiff[1].length) {
       continue;
     }
diff --git a/javascript/tests/diff_match_patch_test.js b/javascript/tests/diff_match_patch_test.js
index 4222ce6..35d9de4 100644
--- a/javascript/tests/diff_match_patch_test.js
+++ b/javascript/tests/diff_match_patch_test.js
@@ -551,13 +551,40 @@ function testDiffDelta() {
   })();
 
   // Unicode - splitting surrogates
+  try {
+    assertEquivalent(
+      dmp.diff_toDelta([[DIFF_INSERT,'\ud83c\udd71'], [DIFF_EQUAL, '\ud83c\udd70\ud83c\udd71']]),
+      dmp.diff_toDelta(dmp.diff_main('\ud83c\udd70\ud83c\udd71', '\ud83c\udd71\ud83c\udd70\ud83c\udd71'))
+    );
+  } catch ( e ) {
+    assertEquals('Inserting similar surrogate pair at beginning', 'crashed');
+  }
+
   try {
     assertEquivalent(
       dmp.diff_toDelta([[DIFF_EQUAL,'\ud83c\udd70'], [DIFF_INSERT, '\ud83c\udd70'], [DIFF_EQUAL, '\ud83c\udd71']]),
       dmp.diff_toDelta(dmp.diff_main('\ud83c\udd70\ud83c\udd71', '\ud83c\udd70\ud83c\udd70\ud83c\udd71'))
     );
   } catch ( e ) {
-    assertEquals('Inserting similar surrogate pair', 'crashed');
+    assertEquals('Inserting similar surrogate pair in the middle', 'crashed');
+  }
+
+  try {
+    assertEquivalent(
+      dmp.diff_toDelta([[DIFF_DELETE,'\ud83c\udd71'], [DIFF_EQUAL, '\ud83c\udd70\ud83c\udd71']]),
+      dmp.diff_toDelta(dmp.diff_main('\ud83c\udd71\ud83c\udd70\ud83c\udd71', '\ud83c\udd70\ud83c\udd71'))
+    );
+  } catch ( e ) {
+    assertEquals('Deleting similar surrogate pair at the beginning', 'crashed');
+  }
+
+  try {
+    assertEquivalent(
+      dmp.diff_toDelta([[DIFF_EQUAL, '\ud83c\udd70'], [DIFF_DELETE,'\ud83c\udd72'], [DIFF_EQUAL, '\ud83c\udd71']]),
+      dmp.diff_toDelta(dmp.diff_main('\ud83c\udd70\ud83c\udd72\ud83c\udd71', '\ud83c\udd70\ud83c\udd71'))
+    );
+  } catch ( e ) {
+    assertEquals('Deleting similar surrogate pair in the middle', 'crashed');
   }
 
   try {

From 1d166fec7e005bfbbb456ae9817be075bba20e7e Mon Sep 17 00:00:00 2001
From: Dennis Snell <dennis.snell@automattic.com>
Date: Mon, 16 Dec 2019 12:44:00 -0700
Subject: [PATCH 18/34] Apply patch fix to objective-c

---
 objectivec/DiffMatchPatch.m | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/objectivec/DiffMatchPatch.m b/objectivec/DiffMatchPatch.m
index 495a07b..ba0ab76 100755
--- a/objectivec/DiffMatchPatch.m
+++ b/objectivec/DiffMatchPatch.m
@@ -1301,11 +1301,15 @@ - (NSString *)diff_toDelta:(NSMutableArray *)diffs;
   NSMutableString *delta = [NSMutableString string];
   UniChar lastEnd = 0;
   for (Diff *aDiff in diffs) {
+    if (0 == [aDiff.text length]) {
+        continue;
+    }
 
     UniChar thisTop = [aDiff.text characterAtIndex:0];
     UniChar thisEnd = [aDiff.text characterAtIndex:([aDiff.text length]-1)];
 
     if (CFStringIsSurrogateHighCharacter(thisEnd)) {
+      lastEnd = thisEnd;
       aDiff.text = [aDiff.text substringToIndex:([aDiff.text length] - 1)];
     }
 
@@ -1313,7 +1317,6 @@ - (NSString *)diff_toDelta:(NSMutableArray *)diffs;
       aDiff.text = [NSString stringWithFormat:@"%C%@", lastEnd, aDiff.text];
     }
 
-    lastEnd = thisEnd;
     if (0 == [aDiff.text length]) {
       continue;
     }

From 9dede7fd48a06242b39b92878cfa1bd6d8375442 Mon Sep 17 00:00:00 2001
From: Dennis Snell <dennis.snell@automattic.com>
Date: Mon, 16 Dec 2019 13:27:14 -0700
Subject: [PATCH 19/34] Add objective-c tests

---
 objectivec/Tests/DiffMatchPatchTest.m | 50 +++++++++++++++++++++++++++
 1 file changed, 50 insertions(+)

diff --git a/objectivec/Tests/DiffMatchPatchTest.m b/objectivec/Tests/DiffMatchPatchTest.m
index 2869492..8761aa0 100755
--- a/objectivec/Tests/DiffMatchPatchTest.m
+++ b/objectivec/Tests/DiffMatchPatchTest.m
@@ -764,6 +764,56 @@ - (void)test_diff_deltaTest {
   expectedString = [patchResult firstObject];
   XCTAssertEqualObjects(@"☺️😃🖖🏿", expectedString, @"Output String should match the Edited one!");
 
+  // Unicode - splitting surrogates
+
+  // Inserting similar surrogate pair at beginning
+  diffs = [NSMutableArray arrayWithObjects:
+           [Diff diffWithOperation:DIFF_INSERT andText:@"🅱"],
+           [Diff diffWithOperation:DIFF_EQUAL andText:@"🅰🅱"],
+           nil];
+  XCTAssertEqualObjects( [dmp diff_toDelta:diffs], [dmp diff_toDelta:[dmp diff_mainOfOldString:@"🅰🅱" andNewString:@"🅱🅰🅱"]]);
+
+  // Inserting similar surrogate pair in the middle
+  diffs = [NSMutableArray arrayWithObjects:
+           [Diff diffWithOperation:DIFF_EQUAL andText:@"🅰"],
+           [Diff diffWithOperation:DIFF_INSERT andText:@"🅰"],
+           [Diff diffWithOperation:DIFF_EQUAL andText:@"🅱"],
+           nil];
+  XCTAssertEqualObjects( [dmp diff_toDelta:diffs], [dmp diff_toDelta:[dmp diff_mainOfOldString:@"🅰🅱" andNewString:@"🅰🅰🅱"]]);
+
+  // Deleting similar surrogate pair at the beginning
+  diffs = [NSMutableArray arrayWithObjects:
+           [Diff diffWithOperation:DIFF_DELETE andText:@"🅱"],
+           [Diff diffWithOperation:DIFF_EQUAL andText:@"🅰🅱"],
+           nil];
+  XCTAssertEqualObjects( [dmp diff_toDelta:diffs], [dmp diff_toDelta:[dmp diff_mainOfOldString:@"🅱🅰🅱" andNewString:@"🅰🅱"]]);
+
+  // Deleting similar surrogate pair in the middle
+  diffs = [NSMutableArray arrayWithObjects:
+           [Diff diffWithOperation:DIFF_EQUAL andText:@"🅰"],
+           [Diff diffWithOperation:DIFF_DELETE andText:@"🅲"],
+           [Diff diffWithOperation:DIFF_EQUAL andText:@"🅱"],
+           nil];
+  XCTAssertEqualObjects( [dmp diff_toDelta:diffs], [dmp diff_toDelta:[dmp diff_mainOfOldString:@"🅰🅲🅱" andNewString:@"🅰🅱"]]);
+
+  // Swapping surrogate pairs
+  diffs = [NSMutableArray arrayWithObjects:
+           [Diff diffWithOperation:DIFF_DELETE andText:@"🅰"],
+           [Diff diffWithOperation:DIFF_INSERT andText:@"🅱"],
+           nil];
+  XCTAssertEqualObjects( [dmp diff_toDelta:diffs], [dmp diff_toDelta:[dmp diff_mainOfOldString:@"🅰" andNewString:@"🅱"]]);
+
+  // Swapping surrogate pairs
+  XCTAssertEqualObjects( [dmp diff_toDelta:([NSMutableArray arrayWithObjects:
+                                            [Diff diffWithOperation:DIFF_DELETE andText:@"🅰"],
+                                            [Diff diffWithOperation:DIFF_INSERT andText:@"🅱"],
+                                             nil])],
+                        [dmp diff_toDelta:([NSMutableArray arrayWithObjects:
+                                            [Diff diffWithOperation:DIFF_EQUAL andText:[NSString stringWithFormat:@"%C", 0xd83c]],
+                                            [Diff diffWithOperation:DIFF_DELETE andText:[NSString stringWithFormat:@"%C", 0xdd70]],
+                                            [Diff diffWithOperation:DIFF_INSERT andText:[NSString stringWithFormat:@"%C", 0xdd71]],
+                                            nil])]);
+
   // Verify pool of unchanged characters.
   diffs = [NSMutableArray arrayWithObject:
        [Diff diffWithOperation:DIFF_INSERT andText:@"A-Z a-z 0-9 - _ . ! ~ * ' ( ) ; / ? : @ & = + $ , # "]];

From dbada062e3ebbe7bb39ba9d187b39a02740f6dfa Mon Sep 17 00:00:00 2001
From: Dennis Snell <dennis.snell@automattic.com>
Date: Mon, 16 Dec 2019 13:57:57 -0700
Subject: [PATCH 20/34] JavaScript: Use `digit16` instead of `parseInt()`

There's no need to validate the entire range of input integers.
Using `digit16()` will be faster and give us more precise validation.
---
 javascript/diff_match_patch_uncompressed.js | 31 +++++++++++++++++----
 1 file changed, 26 insertions(+), 5 deletions(-)

diff --git a/javascript/diff_match_patch_uncompressed.js b/javascript/diff_match_patch_uncompressed.js
index b15c26c..67bee74 100644
--- a/javascript/diff_match_patch_uncompressed.js
+++ b/javascript/diff_match_patch_uncompressed.js
@@ -1400,6 +1400,28 @@ diff_match_patch.prototype.diff_toDelta = function(diffs) {
   return text.join('\t').replace(/%20/g, ' ');
 };
 
+diff_match_patch.prototype.digit16 = function(c) {
+  switch (c) {
+    case '0': return 0;
+    case '1': return 1;
+    case '2': return 2;
+    case '3': return 3;
+    case '4': return 4;
+    case '5': return 5;
+    case '6': return 6;
+    case '7': return 7;
+    case '8': return 8;
+    case '9': return 9;
+    case 'A': case 'a': return 10;
+    case 'B': case 'b': return 11;
+    case 'C': case 'c': return 12;
+    case 'D': case 'd': return 13;
+    case 'E': case 'e': return 14;
+    case 'F': case 'f': return 15;
+    default: throw new Error('Invalid hex-code');
+  }
+};
+
 /**
  * Decode URI-encoded string but allow for encoded surrogate halves
  * 
@@ -1430,8 +1452,7 @@ diff_match_patch.prototype.decodeURI = function(text) {
       }
 
       // start a percent-sequence
-      var byte1 = parseInt(text.substring(i + 1, i + 3), 16);
-      
+      var byte1 = (this.digit16(text[i + 1]) << 4) + this.digit16(text[i + 2]);
       if ((byte1 & 0x80) === 0) {
         decoded += String.fromCharCode(byte1);
         i += 3;
@@ -1442,7 +1463,7 @@ diff_match_patch.prototype.decodeURI = function(text) {
         throw new URIError('URI malformed');
       }
 
-      var byte2 = parseInt(text.substring(i + 4, i + 6), 16);
+      var byte2 = (this.digit16(text[i + 4]) << 4) + this.digit16(text[i + 5]);
       if ((byte2 & 0xC0) !== 0x80) {
         throw new URIError('URI malformed');
       }
@@ -1457,7 +1478,7 @@ diff_match_patch.prototype.decodeURI = function(text) {
         throw new URIError('URI malformed');
       }
 
-      var byte3 = parseInt(text.substring(i + 7, i + 9), 16);
+      var byte3 = (this.digit16(text[i + 7]) << 4) + this.digit16(text[i + 8]);
       if ((byte3 & 0xC0) !== 0x80) {
         throw new URIError('URI malformed');
       }
@@ -1473,7 +1494,7 @@ diff_match_patch.prototype.decodeURI = function(text) {
         throw new URIError('URI malformed');
       }
 
-      var byte4 = parseInt(text.substring(i + 10, i + 12), 16);
+      var byte4 = (this.digit16(text[i + 10]) << 4) + this.digit16(text[i + 11]);
       if ((byte4 & 0xC0) !== 0x80) {
         throw new URIError('URI malformed');
       }

From 6e03198e3102327d358c7e88e1427eddfe6e6f19 Mon Sep 17 00:00:00 2001
From: Dennis Snell <dennis.snell@automattic.com>
Date: Mon, 16 Dec 2019 14:24:56 -0700
Subject: [PATCH 21/34] Objective-C: Introduce failing test for receiving an
 invalid patch

---
 objectivec/Tests/DiffMatchPatchTest.m | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/objectivec/Tests/DiffMatchPatchTest.m b/objectivec/Tests/DiffMatchPatchTest.m
index 8761aa0..7e31508 100755
--- a/objectivec/Tests/DiffMatchPatchTest.m
+++ b/objectivec/Tests/DiffMatchPatchTest.m
@@ -843,6 +843,11 @@ - (void)test_diff_deltaTest {
   expectedResult = [dmp diff_fromDeltaWithText:@"" andDelta:delta error:NULL];
   XCTAssertEqualObjects(diffs, expectedResult, @"diff_fromDelta: 160kb string. Convert delta string into a diff.");
 
+  // Different versions of the library may have created deltas with
+  // half of a surrogate pair encoded as if it were valid UTF-8
+  XCTAssertEqualObjects([dmp diff_toDelta:([dmp diff_fromDeltaWithText:@"🅰" andDelta:@"-2\t+%F0%9F%85%B1" error:NULL])],
+                        [dmp diff_toDelta:([dmp diff_fromDeltaWithText:@"🅰" andDelta:@"=1\t-1\t+%ED%B5%B1" error:NULL])]);
+
   [dmp release];
 }
 

From 989d6c6e78dd835a3aaa5d0e6bfcea26f4b97b08 Mon Sep 17 00:00:00 2001
From: Dennis Snell <dennis.snell@automattic.com>
Date: Mon, 16 Dec 2019 17:44:28 -0700
Subject: [PATCH 22/34] Python: Update patch and handle wide/narrow compilation

Python can be compiled in "narrow" mode or "wide" mode which determines
how wide the internal string units are. In narrow mode we have UCS-2
code units and higher-order Unicode code points will be stored as
surrogate pairs. In wide mode we have UCS-4 code units and so all
Unicode code points will be stored as a single item in the string.

This patch incorporate a decision based on the internal string width to
run the native-looking `toDelta` or the _encoded_ version. In the
_encoded_ version we explicitly encode the string to `utf-16be` for
consistency sake with the other libraries.

We _could_ always run the encoded version but I suspect that the native
version will be faster and many deployments will be running narrow mode.
---
 python2/diff_match_patch.py | 68 +++++++++++++++++++++++++++++--------
 1 file changed, 53 insertions(+), 15 deletions(-)

diff --git a/python2/diff_match_patch.py b/python2/diff_match_patch.py
index 71cbd19..1738bd6 100644
--- a/python2/diff_match_patch.py
+++ b/python2/diff_match_patch.py
@@ -1137,16 +1137,47 @@ def diff_levenshtein(self, diffs):
     return levenshtein
 
   @classmethod
-  def is_high_surrogate(cls, utf16be_bytes):
-    c = struct.unpack('>H', utf16be_bytes)[0]
-    return c >= 0xd800 and c <= 0xdbff
+  def is_high_surrogate(cls, c):
+    return 0xd800 <= c <= 0xdbff
 
   @classmethod
-  def is_low_surrogate(cls, utf16be_bytes):
-    c = struct.unpack('>H', utf16be_bytes)[0]
-    return c >= 0xdc00 and c <= 0xdfff
+  def is_low_surrogate(cls, c):
+    return 0xdc00 <= c <= 0xdfff
 
-  def diff_toDelta(self, diffs):
+  @classmethod
+  def ucs2ord(cls, utf16be_bytes):
+    return struct.unpack('>H', utf16be_bytes)[0]
+
+  def diff_toDelta_narrow(self, diffs):
+    text = []
+    last_end = None
+    for (op, data) in diffs:
+      if 0 == len(data):
+        continue
+
+      this_top = data[0]
+      this_end = data[-1]
+
+      if self.is_high_surrogate(ord(this_end)):
+        last_end = this_end
+        data = data[:-1]
+
+      if last_end and self.is_high_surrogate(ord(last_end)) and self.is_low_surrogate(ord(this_top)):
+        data = last_end + data
+
+      if 0 == len(data):
+        continue
+
+      if op == self.DIFF_INSERT:
+        # High ascii will raise UnicodeDecodeError.  Use Unicode instead.
+        text.append("+" + urllib.quote(data.encode('utf-8'), "!~*'();/?:@&=+$,# "))
+      elif op == self.DIFF_DELETE:
+        text.append("-%d" % len(data))
+      elif op == self.DIFF_EQUAL:
+        text.append("=%d" % len(data))
+    return "\t".join(text)
+
+  def diff_toDelta_wide(self, diffs):
     """Crush the diff into an encoded string which describes the operations
     required to transform text1 into text2.
     E.g. =3\t-2\t+ing  -> Keep 3 chars, delete 2 chars, insert 'ing'.
@@ -1161,31 +1192,38 @@ def diff_toDelta(self, diffs):
     text = []
     last_end = None
     for (op, data) in diffs:
+      if 0 == len(data):
+        continue
+
       encoded = data.encode('utf-16be')
       this_top = encoded[0:2]
       this_end = encoded[-2:]
 
-      if self.is_high_surrogate(this_end):
+      if self.is_high_surrogate(self.ucs2ord(this_end)):
+        last_end = this_end
         encoded = encoded[0:-2]
 
-      if last_end and self.is_high_surrogate(last_end) and self.is_low_surrogate(this_top):
+      if last_end and self.is_high_surrogate(self.ucs2ord(last_end)) and self.is_low_surrogate(self.ucs2ord(this_top)):
         encoded = last_end + encoded
 
-      data = encoded.decode('utf-16be')
-      last_end = this_end
       if 0 == len(encoded):
         continue
 
       if op == self.DIFF_INSERT:
         # High ascii will raise UnicodeDecodeError.  Use Unicode instead.
-        data = data.encode("utf-8")
-        text.append("+" + urllib.quote(data, "!~*'();/?:@&=+$,# "))
+        text.append("+" + urllib.quote(encoded.decode('utf-16be').encode('utf-8'), "!~*'();/?:@&=+$,# "))
       elif op == self.DIFF_DELETE:
-        text.append("-%d" % (len(data.encode('utf-16be')) // 2))
+        text.append("-%d" % (len(encoded) // 2))
       elif op == self.DIFF_EQUAL:
-        text.append("=%d" % (len(data.encode('utf-16be')) // 2))
+        text.append("=%d" % (len(encoded) // 2))
     return "\t".join(text)
 
+  def diff_toDelta(self, diffs, encode_data = sys.maxunicode == 0xFFFF):
+    if encode_data:
+      return self.diff_toDelta_wide(diffs)
+    else:
+      return self.diff_toDelta_narrow(diffs)
+
   def diff_fromDelta(self, text1, delta):
     """Given the original text1, and an encoded string which describes the
     operations required to transform text1 into text2, compute the full diff.

From 22cb3961e2f84c2e69d1a96c663962144e1d0edd Mon Sep 17 00:00:00 2001
From: Dennis Snell <dennis.snell@automattic.com>
Date: Mon, 16 Dec 2019 17:59:16 -0700
Subject: [PATCH 23/34] Python: Always run encoded toDelta

In testing with `speedtest.py` I found no significant performance impact
for running the "native" narrow-mode `toDelta()` compared to running the
fully-encoding version that operates on bytes.

For the sake of simplicity I'm removing the narrow version.
---
 python2/diff_match_patch.py | 49 ++++---------------------------------
 1 file changed, 5 insertions(+), 44 deletions(-)

diff --git a/python2/diff_match_patch.py b/python2/diff_match_patch.py
index 1738bd6..8b26125 100644
--- a/python2/diff_match_patch.py
+++ b/python2/diff_match_patch.py
@@ -1138,46 +1138,13 @@ def diff_levenshtein(self, diffs):
 
   @classmethod
   def is_high_surrogate(cls, c):
-    return 0xd800 <= c <= 0xdbff
+    return 0xd800 <= struct.unpack('>H', c)[0] <= 0xdbff
 
   @classmethod
   def is_low_surrogate(cls, c):
-    return 0xdc00 <= c <= 0xdfff
+    return 0xdc00 <= struct.unpack('>H', c)[0] <= 0xdfff
 
-  @classmethod
-  def ucs2ord(cls, utf16be_bytes):
-    return struct.unpack('>H', utf16be_bytes)[0]
-
-  def diff_toDelta_narrow(self, diffs):
-    text = []
-    last_end = None
-    for (op, data) in diffs:
-      if 0 == len(data):
-        continue
-
-      this_top = data[0]
-      this_end = data[-1]
-
-      if self.is_high_surrogate(ord(this_end)):
-        last_end = this_end
-        data = data[:-1]
-
-      if last_end and self.is_high_surrogate(ord(last_end)) and self.is_low_surrogate(ord(this_top)):
-        data = last_end + data
-
-      if 0 == len(data):
-        continue
-
-      if op == self.DIFF_INSERT:
-        # High ascii will raise UnicodeDecodeError.  Use Unicode instead.
-        text.append("+" + urllib.quote(data.encode('utf-8'), "!~*'();/?:@&=+$,# "))
-      elif op == self.DIFF_DELETE:
-        text.append("-%d" % len(data))
-      elif op == self.DIFF_EQUAL:
-        text.append("=%d" % len(data))
-    return "\t".join(text)
-
-  def diff_toDelta_wide(self, diffs):
+  def diff_toDelta(self, diffs):
     """Crush the diff into an encoded string which describes the operations
     required to transform text1 into text2.
     E.g. =3\t-2\t+ing  -> Keep 3 chars, delete 2 chars, insert 'ing'.
@@ -1199,11 +1166,11 @@ def diff_toDelta_wide(self, diffs):
       this_top = encoded[0:2]
       this_end = encoded[-2:]
 
-      if self.is_high_surrogate(self.ucs2ord(this_end)):
+      if self.is_high_surrogate(this_end):
         last_end = this_end
         encoded = encoded[0:-2]
 
-      if last_end and self.is_high_surrogate(self.ucs2ord(last_end)) and self.is_low_surrogate(self.ucs2ord(this_top)):
+      if last_end and self.is_high_surrogate(last_end) and self.is_low_surrogate(this_top):
         encoded = last_end + encoded
 
       if 0 == len(encoded):
@@ -1218,12 +1185,6 @@ def diff_toDelta_wide(self, diffs):
         text.append("=%d" % (len(encoded) // 2))
     return "\t".join(text)
 
-  def diff_toDelta(self, diffs, encode_data = sys.maxunicode == 0xFFFF):
-    if encode_data:
-      return self.diff_toDelta_wide(diffs)
-    else:
-      return self.diff_toDelta_narrow(diffs)
-
   def diff_fromDelta(self, text1, delta):
     """Given the original text1, and an encoded string which describes the
     operations required to transform text1 into text2, compute the full diff.

From 3c31e6273f19bb2dfce28f4dd4654e03af8fdf1c Mon Sep 17 00:00:00 2001
From: Dennis Snell <dennis.snell@automattic.com>
Date: Tue, 17 Dec 2019 16:48:21 -0700
Subject: [PATCH 24/34] Python: Add tests and update Python3 toDelta fix

---
 python2/tests/diff_match_patch_test.py | 76 ++++++++++++++++++++++++++
 python3/diff_match_patch.py            |  3 +
 python3/tests/diff_match_patch_test.py | 63 +++++++++++++++++++++
 3 files changed, 142 insertions(+)

diff --git a/python2/tests/diff_match_patch_test.py b/python2/tests/diff_match_patch_test.py
index fc633bc..94f5fd3 100644
--- a/python2/tests/diff_match_patch_test.py
+++ b/python2/tests/diff_match_patch_test.py
@@ -445,6 +445,82 @@ def testDiffDelta(self):
     delta = self.dmp.diff_toDelta(diffs)
     self.assertEquals("=2\t+%F0%9F%99%8C\t=2", delta)
 
+    # Unicode: split surrogates
+    # Inserting similar surrogate pair at beginning
+    self.assertEquals(
+      self.dmp.diff_toDelta([
+        (self.dmp.DIFF_INSERT, u'\U0001F171'),
+        (self.dmp.DIFF_EQUAL, u'\U0001F170\U0001F171')
+      ]),
+      self.dmp.diff_toDelta(self.dmp.diff_main(
+        u'\U0001F170\U0001F171',
+        u'\U0001F171\U0001F170\U0001F171'
+      ))
+    )
+
+    # Inserting similar surrogate pair in the middle
+    self.assertEquals(
+      self.dmp.diff_toDelta([
+        (self.dmp.DIFF_EQUAL, u'\U0001F170'),
+        (self.dmp.DIFF_INSERT, u'\U0001F172'),
+        (self.dmp.DIFF_EQUAL, u'\U0001F171')
+      ]),
+      self.dmp.diff_toDelta(self.dmp.diff_main(
+        u'\U0001F170\U0001F171',
+        u'\U0001F170\U0001F172\U0001F171'
+      ))
+    )
+
+    # Deleting similar surogate pair at the beginning
+    self.assertEquals(
+      self.dmp.diff_toDelta([
+        (self.dmp.DIFF_DELETE, u'\U0001F171'),
+        (self.dmp.DIFF_EQUAL, u'\U0001F170\U0001F171')
+      ]),
+      self.dmp.diff_toDelta(self.dmp.diff_main(
+        u'\U0001F171\U0001F170\U0001F171',
+        u'\U0001F170\U0001F171'
+      ))
+    )
+
+    # Deleting similar surogate pair in the middle
+    self.assertEquals(
+      self.dmp.diff_toDelta([
+        (self.dmp.DIFF_EQUAL, u'\U0001F170'),
+        (self.dmp.DIFF_DELETE, u'\U0001F172'),
+        (self.dmp.DIFF_EQUAL, u'\U0001F171')
+      ]),
+      self.dmp.diff_toDelta(self.dmp.diff_main(
+        u'\U0001F170\U0001F172\U0001F171',
+        u'\U0001F170\U0001F171'
+      ))
+    )
+
+    # Swap surrogate pair
+    self.assertEquals(
+      self.dmp.diff_toDelta([
+        (self.dmp.DIFF_DELETE, u'\U0001F170'),
+        (self.dmp.DIFF_INSERT, u'\U0001F171')
+      ]),
+      self.dmp.diff_toDelta(self.dmp.diff_main(
+        u'\U0001F170',
+        u'\U0001F171'
+      ))
+    )
+
+    # Swap surrogate pair, force the invalid diff groups
+    self.assertEquals(
+      self.dmp.diff_toDelta([
+        (self.dmp.DIFF_INSERT, u'\U0001F170'),
+        (self.dmp.DIFF_DELETE, u'\U0001F171')
+      ]),
+      self.dmp.diff_toDelta([
+        (self.dmp.DIFF_EQUAL, u'\ud83c'),
+        (self.dmp.DIFF_INSERT, u'\udd70'),
+        (self.dmp.DIFF_DELETE, u'\udd71')
+      ])
+    )
+
     # Verify pool of unchanged characters.
     diffs = [(self.dmp.DIFF_INSERT, "A-Z a-z 0-9 - _ . ! ~ * ' ( ) ; / ? : @ & = + $ , # ")]
     text2 = self.dmp.diff_text2(diffs)
diff --git a/python3/diff_match_patch.py b/python3/diff_match_patch.py
index 99aa853..3bf825c 100644
--- a/python3/diff_match_patch.py
+++ b/python3/diff_match_patch.py
@@ -1148,6 +1148,9 @@ def diff_toDelta(self, diffs):
     """
     text = []
     for (op, data) in diffs:
+      if 0 == len(data):
+        continue
+
       if op == self.DIFF_INSERT:
         # High ascii will raise UnicodeDecodeError.  Use Unicode instead.
         data = data.encode("utf-8")
diff --git a/python3/tests/diff_match_patch_test.py b/python3/tests/diff_match_patch_test.py
index 9474762..4ff16ab 100644
--- a/python3/tests/diff_match_patch_test.py
+++ b/python3/tests/diff_match_patch_test.py
@@ -462,6 +462,69 @@ def testDiffDelta(self):
     # Convert delta string into a diff.
     self.assertEqual(diffs, self.dmp.diff_fromDelta("", delta))
 
+    # Unicode: split surrogates
+    self.assertEqual(
+      self.dmp.diff_toDelta([
+        (self.dmp.DIFF_INSERT, '\U0001F171'),
+        (self.dmp.DIFF_EQUAL, '\U0001F170\U0001F171')
+      ]),
+      self.dmp.diff_toDelta(self.dmp.diff_main(
+        '\U0001F170\U0001F171',
+        '\U0001F171\U0001F170\U0001F171'
+      )),
+      'Inserting similar surrogate pair at beginning'
+    )
+
+    self.assertEqual(
+      self.dmp.diff_toDelta([
+        (self.dmp.DIFF_EQUAL, '\U0001F170'),
+        (self.dmp.DIFF_INSERT, '\U0001F172'),
+        (self.dmp.DIFF_EQUAL, '\U0001F171')
+      ]),
+      self.dmp.diff_toDelta(self.dmp.diff_main(
+        '\U0001F170\U0001F171',
+        '\U0001F170\U0001F172\U0001F171'
+      )),
+      'Inserting similar surrogate pair in the middle'
+    )
+
+    self.assertEqual(
+      self.dmp.diff_toDelta([
+        (self.dmp.DIFF_DELETE, '\U0001F171'),
+        (self.dmp.DIFF_EQUAL, '\U0001F170\U0001F171')
+      ]),
+      self.dmp.diff_toDelta(self.dmp.diff_main(
+        '\U0001F171\U0001F170\U0001F171',
+        '\U0001F170\U0001F171'
+      )),
+      'Deleting similar surogate pair at the beginning'
+    )
+
+    self.assertEqual(
+      self.dmp.diff_toDelta([
+        (self.dmp.DIFF_EQUAL, '\U0001F170'),
+        (self.dmp.DIFF_DELETE, '\U0001F172'),
+        (self.dmp.DIFF_EQUAL, '\U0001F171')
+      ]),
+      self.dmp.diff_toDelta(self.dmp.diff_main(
+        '\U0001F170\U0001F172\U0001F171',
+        '\U0001F170\U0001F171'
+      )),
+      'Deleting similar surogate pair in the middle'
+    )
+
+    self.assertEqual(
+      self.dmp.diff_toDelta([
+        (self.dmp.DIFF_DELETE, '\U0001F170'),
+        (self.dmp.DIFF_INSERT, '\U0001F171')
+      ]),
+      self.dmp.diff_toDelta(self.dmp.diff_main(
+        '\U0001F170',
+        '\U0001F171'
+      )),
+      'Swap surrogate pair'
+    )
+
     # 160 kb string.
     a = "abcdefghij"
     for i in range(14):

From df217532a84dfbc63fa8049f94a331776421ce3a Mon Sep 17 00:00:00 2001
From: Dennis Snell <dennis.snell@automattic.com>
Date: Thu, 19 Dec 2019 10:14:34 -0700
Subject: [PATCH 25/34] Update Objective-C code to handle invalid incoming
 deltas

---
 objectivec/DiffMatchPatch.m | 123 +++++++++++++++++++++++++++++++++++-
 1 file changed, 122 insertions(+), 1 deletion(-)

diff --git a/objectivec/DiffMatchPatch.m b/objectivec/DiffMatchPatch.m
index ba0ab76..486c0b3 100755
--- a/objectivec/DiffMatchPatch.m
+++ b/objectivec/DiffMatchPatch.m
@@ -1342,6 +1342,127 @@ - (NSString *)diff_toDelta:(NSMutableArray *)diffs;
   return delta;
 }
 
+- (int)diff_digit16:(unichar)c
+{
+    switch (c) {
+        case '0': return 0;
+        case '1': return 1;
+        case '2': return 2;
+        case '3': return 3;
+        case '4': return 4;
+        case '5': return 5;
+        case '6': return 6;
+        case '7': return 7;
+        case '8': return 8;
+        case '9': return 9;
+        case 'A': case 'a': return 10;
+        case 'B': case 'b': return 11;
+        case 'C': case 'c': return 12;
+        case 'D': case 'd': return 13;
+        case 'E': case 'e': return 14;
+        case 'F': case 'f': return 15;
+        default:
+            [NSException raise:@"Invalid percent-encoded string" format:@"%c is not a hex digit", c];
+    }
+}
+
+- (NSString *)diff_decodeURIWithText:(NSString *)percentEncoded
+{
+    unichar decoded[[percentEncoded length]];
+    int input = 0;
+    int output = 0;
+    
+    @try {
+        while (input < [percentEncoded length]) {
+            unichar c = [percentEncoded characterAtIndex:input];
+
+            if ('%' != c) {
+                decoded[output++] = c;
+                input += 1;
+                continue;
+            }
+
+            int byte1 = ([self diff_digit16:[percentEncoded characterAtIndex:(input+1)]] << 4) +
+                         [self diff_digit16:[percentEncoded characterAtIndex:(input+2)]];
+
+            if ((byte1 & 0x80) == 0) {
+                decoded[output++] = byte1;
+                input += 3;
+                continue;
+            }
+
+            if ('%' != [percentEncoded characterAtIndex:(input + 3)]) {
+                [NSException raise:@"Invalid percent-encoded string" format:@"Cannot decode UTF-8 sequence: %@", percentEncoded];
+            }
+
+            int byte2 = ([self diff_digit16:[percentEncoded characterAtIndex:(input+4)]] << 4) +
+                         [self diff_digit16:[percentEncoded characterAtIndex:(input+5)]];
+
+            if ((byte2 & 0xC0) != 0x80) {
+                [NSException raise:@"Invalid percent-encoded string" format:@"Cannot decode UTF-8 sequence: %@", percentEncoded];
+            }
+
+            byte2 = byte2 & 0x3F;
+
+            if ((byte1 & 0xE0) == 0xC0) {
+                decoded[output++] = ((byte1 & 0x1F) << 6) | byte2;
+                input += 6;
+                continue;
+            }
+
+            if ('%' != [percentEncoded characterAtIndex:(input + 6)]) {
+                [NSException raise:@"Invalid percent-encoded string" format:@"Cannot decode UTF-8 sequence: %@", percentEncoded];
+            }
+
+            int byte3 = ([self diff_digit16:[percentEncoded characterAtIndex:(input+7)]] << 4) +
+                         [self diff_digit16:[percentEncoded characterAtIndex:(input+8)]];
+
+            if ((byte3 & 0xC0) != 0x80) {
+                [NSException raise:@"Invalid percent-encoded string" format:@"Cannot decode UTF-8 sequence: %@", percentEncoded];
+            }
+
+            byte3 = byte3 & 0x3F;
+
+            if ((byte1 & 0xF0) == 0xE0) {
+                decoded[output++] = ((byte1 & 0x0F) << 12) | (byte2 << 6) | byte3;
+                input += 9;
+                continue;
+            }
+
+            if ('%' != [percentEncoded characterAtIndex:(input + 9)]) {
+                [NSException raise:@"Invalid percent-encoded string" format:@"Cannot decode UTF-8 sequence: %@", percentEncoded];
+            }
+
+            int byte4 = ([self diff_digit16:[percentEncoded characterAtIndex:(input+10)]] << 4) +
+                         [self diff_digit16:[percentEncoded characterAtIndex:(input+11)]];
+
+            if ((byte4 & 0xC0) != 0x80) {
+                [NSException raise:@"Invalid percent-encoded string" format:@"Cannot decode UTF-8 sequence: %@", percentEncoded];
+            }
+
+            byte4 = byte4 & 0x3F;
+
+            if ((byte1 & 0xF8) == 0xF0) {
+                int codePoint = ((byte1 & 0x07) << 0x12) | (byte2 << 0x0C) | (byte3 << 0x06) | byte4;
+                if (codePoint >= 0x010000 && codePoint <= 0x10FFFF) {
+                    codePoint -= 0x010000;
+                    decoded[output++] = ((codePoint >> 10) & 0x3FF) | 0xD800;
+                    decoded[output++] = 0xDC00 | (codePoint & 0x3FF);
+                    input += 12;
+                    continue;
+                }
+            }
+
+            [NSException raise:@"Invalid percent-encoded string" format:@"Cannot decode UTF-8 sequence: %@", percentEncoded];
+        }
+    }
+    @catch (NSException *e) {
+        return nil;
+    }
+    
+    return [NSString stringWithCharacters:decoded length:output];
+}
+
 /**
  * Given the original text1, and an encoded NSString which describes the
  * operations required to transform text1 into text2, compute the full diff.
@@ -1369,7 +1490,7 @@ - (NSMutableArray *)diff_fromDeltaWithText:(NSString *)text1
     NSString *param = [token substringFromIndex:1];
     switch ([token characterAtIndex:0]) {
       case '+':
-        param = [param diff_stringByReplacingPercentEscapesForEncodeUriCompatibility];
+        param = [self diff_decodeURIWithText:param];
         if (param == nil) {
           if (error != NULL) {
             errorDetail = [NSDictionary dictionaryWithObjectsAndKeys:

From 9a741a49445fb72f8ab892678cd0f97a9b58ecbf Mon Sep 17 00:00:00 2001
From: Dennis Snell <dennis.snell@automattic.com>
Date: Thu, 19 Dec 2019 12:24:58 -0700
Subject: [PATCH 26/34] JavaScript: Fix known-broken diffs from objective-c

---
 javascript/diff_match_patch_uncompressed.js | 8 +++++++-
 javascript/tests/diff_match_patch_test.js   | 9 +++++++++
 2 files changed, 16 insertions(+), 1 deletion(-)

diff --git a/javascript/diff_match_patch_uncompressed.js b/javascript/diff_match_patch_uncompressed.js
index 67bee74..2b93ecc 100644
--- a/javascript/diff_match_patch_uncompressed.js
+++ b/javascript/diff_match_patch_uncompressed.js
@@ -1512,7 +1512,13 @@ diff_match_patch.prototype.decodeURI = function(text) {
       throw new URIError('URI malformed');
     }
 
-    return decoded;
+    // some objective-c versions of the library produced patches with
+    // (null) in the place where surrogates were split across diff
+    // boundaries. if we leave those in we'll be stuck with a
+    // high-surrogate (null) low-surrogate pattern that will break
+    // deeper in the library or consumping application. we'll "fix"
+    // these by dropping the (null) and re-joining the surrogate halves
+    return decoded.replace(/([\uD800-\uDBFF])\(null\)([\uDC00-\uDFFF])/g, "$1$2");
   }
 };
 
diff --git a/javascript/tests/diff_match_patch_test.js b/javascript/tests/diff_match_patch_test.js
index 35d9de4..9ea1c6e 100644
--- a/javascript/tests/diff_match_patch_test.js
+++ b/javascript/tests/diff_match_patch_test.js
@@ -605,6 +605,15 @@ function testDiffDelta() {
     assertEquals('Swap surrogate pair', 'crashed');
   }
 
+  try {
+    assertEquivalent(
+      dmp.diff_fromDelta('', '+%ED%A0%BC%28null%29%ED%B5%B0'),
+      [[DIFF_INSERT, '\ud83c\udd70']]
+    );
+  } catch ( e ) {
+    assertEquals('Invalid diff from objective-c with (null) string' );
+  }
+
   // Empty diff groups
   assertEquivalent(
     dmp.diff_toDelta([[DIFF_EQUAL, 'abcdef'], [DIFF_DELETE, ''], [DIFF_INSERT, 'ghijk']]),

From 8e5241bf1787a214c1442beb6d73cd1f741416b6 Mon Sep 17 00:00:00 2001
From: Dennis Snell <dennis.snell@automattic.com>
Date: Thu, 19 Dec 2019 12:47:12 -0700
Subject: [PATCH 27/34] Objective-C: Update from feedback - idiomatic code and
 bounds checks

---
 objectivec/DiffMatchPatch.m | 36 +++++++++++++++++++++++-------------
 1 file changed, 23 insertions(+), 13 deletions(-)

diff --git a/objectivec/DiffMatchPatch.m b/objectivec/DiffMatchPatch.m
index 486c0b3..2d1befa 100755
--- a/objectivec/DiffMatchPatch.m
+++ b/objectivec/DiffMatchPatch.m
@@ -1368,9 +1368,15 @@ - (int)diff_digit16:(unichar)c
 
 - (NSString *)diff_decodeURIWithText:(NSString *)percentEncoded
 {
-    unichar decoded[[percentEncoded length]];
-    int input = 0;
-    int output = 0;
+    NSInteger inputLength = [percentEncoded length];
+
+    if (0 == inputLength) {
+        return @"";
+    }
+
+    unichar decoded[inputLength];
+    NSInteger input = 0;
+    NSInteger output = 0;
     
     @try {
         while (input < [percentEncoded length]) {
@@ -1382,6 +1388,10 @@ - (NSString *)diff_decodeURIWithText:(NSString *)percentEncoded
                 continue;
             }
 
+            if (inputLength < input + 3) {
+                return nil;
+            }
+
             int byte1 = ([self diff_digit16:[percentEncoded characterAtIndex:(input+1)]] << 4) +
                          [self diff_digit16:[percentEncoded characterAtIndex:(input+2)]];
 
@@ -1391,15 +1401,15 @@ - (NSString *)diff_decodeURIWithText:(NSString *)percentEncoded
                 continue;
             }
 
-            if ('%' != [percentEncoded characterAtIndex:(input + 3)]) {
-                [NSException raise:@"Invalid percent-encoded string" format:@"Cannot decode UTF-8 sequence: %@", percentEncoded];
+            if (inputLength < input + 6 || '%' != [percentEncoded characterAtIndex:(input + 3)]) {
+                return nil;
             }
 
             int byte2 = ([self diff_digit16:[percentEncoded characterAtIndex:(input+4)]] << 4) +
                          [self diff_digit16:[percentEncoded characterAtIndex:(input+5)]];
 
             if ((byte2 & 0xC0) != 0x80) {
-                [NSException raise:@"Invalid percent-encoded string" format:@"Cannot decode UTF-8 sequence: %@", percentEncoded];
+                return nil;
             }
 
             byte2 = byte2 & 0x3F;
@@ -1410,15 +1420,15 @@ - (NSString *)diff_decodeURIWithText:(NSString *)percentEncoded
                 continue;
             }
 
-            if ('%' != [percentEncoded characterAtIndex:(input + 6)]) {
-                [NSException raise:@"Invalid percent-encoded string" format:@"Cannot decode UTF-8 sequence: %@", percentEncoded];
+            if (inputLength < input + 9 || '%' != [percentEncoded characterAtIndex:(input + 6)]) {
+                return nil;
             }
 
             int byte3 = ([self diff_digit16:[percentEncoded characterAtIndex:(input+7)]] << 4) +
                          [self diff_digit16:[percentEncoded characterAtIndex:(input+8)]];
 
             if ((byte3 & 0xC0) != 0x80) {
-                [NSException raise:@"Invalid percent-encoded string" format:@"Cannot decode UTF-8 sequence: %@", percentEncoded];
+                return nil;
             }
 
             byte3 = byte3 & 0x3F;
@@ -1429,15 +1439,15 @@ - (NSString *)diff_decodeURIWithText:(NSString *)percentEncoded
                 continue;
             }
 
-            if ('%' != [percentEncoded characterAtIndex:(input + 9)]) {
-                [NSException raise:@"Invalid percent-encoded string" format:@"Cannot decode UTF-8 sequence: %@", percentEncoded];
+            if (inputLength < input + 12 || '%' != [percentEncoded characterAtIndex:(input + 9)]) {
+                return nil;
             }
 
             int byte4 = ([self diff_digit16:[percentEncoded characterAtIndex:(input+10)]] << 4) +
                          [self diff_digit16:[percentEncoded characterAtIndex:(input+11)]];
 
             if ((byte4 & 0xC0) != 0x80) {
-                [NSException raise:@"Invalid percent-encoded string" format:@"Cannot decode UTF-8 sequence: %@", percentEncoded];
+                return nil;
             }
 
             byte4 = byte4 & 0x3F;
@@ -1453,7 +1463,7 @@ - (NSString *)diff_decodeURIWithText:(NSString *)percentEncoded
                 }
             }
 
-            [NSException raise:@"Invalid percent-encoded string" format:@"Cannot decode UTF-8 sequence: %@", percentEncoded];
+            return nil;
         }
     }
     @catch (NSException *e) {

From 3a00a83eb18b956e2171676981f8560f3f6b4be9 Mon Sep 17 00:00:00 2001
From: Dennis Snell <dennis.snell@automattic.com>
Date: Thu, 19 Dec 2019 13:25:04 -0700
Subject: [PATCH 28/34] ObjectiveC: Stop doing bounds checking and rely on
 exception-catching

---
 objectivec/DiffMatchPatch.m | 18 ++++--------------
 1 file changed, 4 insertions(+), 14 deletions(-)

diff --git a/objectivec/DiffMatchPatch.m b/objectivec/DiffMatchPatch.m
index 2d1befa..62b1e3f 100755
--- a/objectivec/DiffMatchPatch.m
+++ b/objectivec/DiffMatchPatch.m
@@ -1368,13 +1368,7 @@ - (int)diff_digit16:(unichar)c
 
 - (NSString *)diff_decodeURIWithText:(NSString *)percentEncoded
 {
-    NSInteger inputLength = [percentEncoded length];
-
-    if (0 == inputLength) {
-        return @"";
-    }
-
-    unichar decoded[inputLength];
+    unichar decoded[[percentEncoded length]];
     NSInteger input = 0;
     NSInteger output = 0;
     
@@ -1388,10 +1382,6 @@ - (NSString *)diff_decodeURIWithText:(NSString *)percentEncoded
                 continue;
             }
 
-            if (inputLength < input + 3) {
-                return nil;
-            }
-
             int byte1 = ([self diff_digit16:[percentEncoded characterAtIndex:(input+1)]] << 4) +
                          [self diff_digit16:[percentEncoded characterAtIndex:(input+2)]];
 
@@ -1401,7 +1391,7 @@ - (NSString *)diff_decodeURIWithText:(NSString *)percentEncoded
                 continue;
             }
 
-            if (inputLength < input + 6 || '%' != [percentEncoded characterAtIndex:(input + 3)]) {
+            if ('%' != [percentEncoded characterAtIndex:(input + 3)]) {
                 return nil;
             }
 
@@ -1420,7 +1410,7 @@ - (NSString *)diff_decodeURIWithText:(NSString *)percentEncoded
                 continue;
             }
 
-            if (inputLength < input + 9 || '%' != [percentEncoded characterAtIndex:(input + 6)]) {
+            if ('%' != [percentEncoded characterAtIndex:(input + 6)]) {
                 return nil;
             }
 
@@ -1439,7 +1429,7 @@ - (NSString *)diff_decodeURIWithText:(NSString *)percentEncoded
                 continue;
             }
 
-            if (inputLength < input + 12 || '%' != [percentEncoded characterAtIndex:(input + 9)]) {
+            if ('%' != [percentEncoded characterAtIndex:(input + 9)]) {
                 return nil;
             }
 

From 57c824653dbd76d8576b6cc6db5622cee4e053b1 Mon Sep 17 00:00:00 2001
From: Dennis Snell <dennis.snell@automattic.com>
Date: Thu, 19 Dec 2019 13:31:21 -0700
Subject: [PATCH 29/34] ObjectiveC: Use `uint16` and `uint32` for more
 specified bits

---
 objectivec/DiffMatchPatch.m | 20 ++++++++++----------
 1 file changed, 10 insertions(+), 10 deletions(-)

diff --git a/objectivec/DiffMatchPatch.m b/objectivec/DiffMatchPatch.m
index 62b1e3f..926be4c 100755
--- a/objectivec/DiffMatchPatch.m
+++ b/objectivec/DiffMatchPatch.m
@@ -1342,7 +1342,7 @@ - (NSString *)diff_toDelta:(NSMutableArray *)diffs;
   return delta;
 }
 
-- (int)diff_digit16:(unichar)c
+- (NSInteger)diff_digit16:(unichar)c
 {
     switch (c) {
         case '0': return 0;
@@ -1382,8 +1382,8 @@ - (NSString *)diff_decodeURIWithText:(NSString *)percentEncoded
                 continue;
             }
 
-            int byte1 = ([self diff_digit16:[percentEncoded characterAtIndex:(input+1)]] << 4) +
-                         [self diff_digit16:[percentEncoded characterAtIndex:(input+2)]];
+            uint16 byte1 = ([self diff_digit16:[percentEncoded characterAtIndex:(input+1)]] << 4) +
+                            [self diff_digit16:[percentEncoded characterAtIndex:(input+2)]];
 
             if ((byte1 & 0x80) == 0) {
                 decoded[output++] = byte1;
@@ -1395,8 +1395,8 @@ - (NSString *)diff_decodeURIWithText:(NSString *)percentEncoded
                 return nil;
             }
 
-            int byte2 = ([self diff_digit16:[percentEncoded characterAtIndex:(input+4)]] << 4) +
-                         [self diff_digit16:[percentEncoded characterAtIndex:(input+5)]];
+            uint16 byte2 = ([self diff_digit16:[percentEncoded characterAtIndex:(input+4)]] << 4) +
+                            [self diff_digit16:[percentEncoded characterAtIndex:(input+5)]];
 
             if ((byte2 & 0xC0) != 0x80) {
                 return nil;
@@ -1414,8 +1414,8 @@ - (NSString *)diff_decodeURIWithText:(NSString *)percentEncoded
                 return nil;
             }
 
-            int byte3 = ([self diff_digit16:[percentEncoded characterAtIndex:(input+7)]] << 4) +
-                         [self diff_digit16:[percentEncoded characterAtIndex:(input+8)]];
+            uint16 byte3 = ([self diff_digit16:[percentEncoded characterAtIndex:(input+7)]] << 4) +
+                            [self diff_digit16:[percentEncoded characterAtIndex:(input+8)]];
 
             if ((byte3 & 0xC0) != 0x80) {
                 return nil;
@@ -1433,8 +1433,8 @@ - (NSString *)diff_decodeURIWithText:(NSString *)percentEncoded
                 return nil;
             }
 
-            int byte4 = ([self diff_digit16:[percentEncoded characterAtIndex:(input+10)]] << 4) +
-                         [self diff_digit16:[percentEncoded characterAtIndex:(input+11)]];
+            uint16 byte4 = ([self diff_digit16:[percentEncoded characterAtIndex:(input+10)]] << 4) +
+                            [self diff_digit16:[percentEncoded characterAtIndex:(input+11)]];
 
             if ((byte4 & 0xC0) != 0x80) {
                 return nil;
@@ -1443,7 +1443,7 @@ - (NSString *)diff_decodeURIWithText:(NSString *)percentEncoded
             byte4 = byte4 & 0x3F;
 
             if ((byte1 & 0xF8) == 0xF0) {
-                int codePoint = ((byte1 & 0x07) << 0x12) | (byte2 << 0x0C) | (byte3 << 0x06) | byte4;
+                uint32 codePoint = ((byte1 & 0x07) << 0x12) | (byte2 << 0x0C) | (byte3 << 0x06) | byte4;
                 if (codePoint >= 0x010000 && codePoint <= 0x10FFFF) {
                     codePoint -= 0x010000;
                     decoded[output++] = ((codePoint >> 10) & 0x3FF) | 0xD800;

From 9703fc4eb1dae364a5775dd0f8325ef41cc89236 Mon Sep 17 00:00:00 2001
From: Dennis Snell <dennis.snell@automattic.com>
Date: Thu, 19 Dec 2019 13:53:19 -0700
Subject: [PATCH 30/34] ObjectiveC: Use NSUInteger and explain some bit
 shifting

---
 objectivec/DiffMatchPatch.m | 53 ++++++++++++++++++++++++++++++-------
 1 file changed, 43 insertions(+), 10 deletions(-)

diff --git a/objectivec/DiffMatchPatch.m b/objectivec/DiffMatchPatch.m
index 926be4c..98455af 100755
--- a/objectivec/DiffMatchPatch.m
+++ b/objectivec/DiffMatchPatch.m
@@ -1342,7 +1342,7 @@ - (NSString *)diff_toDelta:(NSMutableArray *)diffs;
   return delta;
 }
 
-- (NSInteger)diff_digit16:(unichar)c
+- (NSUInteger)diff_digit16:(unichar)c
 {
     switch (c) {
         case '0': return 0;
@@ -1366,6 +1366,16 @@ - (NSInteger)diff_digit16:(unichar)c
     }
 }
 
+/**
+* Decode a percent-encoded UTF-8 string into a string of UTF-16 code units
+* This is more permissive than `stringByRemovingPercentEncoding` because
+* that fails if the input represents invalid Unicode characters. However, different
+* diff-match-patch libraries may encode surrogate halves as if they were valid
+* Unicode code points. Therefore, instead of failing or corrupting the output, which
+* `stringByRemovingPercentEncoding` does when it inserts "(null)" in these places
+* we can decode it anyway and then once the string is reconstructed from the diffs
+* we'll end up with valid Unicode again, after the surrogate halves are re-joined
+*/
 - (NSString *)diff_decodeURIWithText:(NSString *)percentEncoded
 {
     unichar decoded[[percentEncoded length]];
@@ -1376,46 +1386,57 @@ - (NSString *)diff_decodeURIWithText:(NSString *)percentEncoded
         while (input < [percentEncoded length]) {
             unichar c = [percentEncoded characterAtIndex:input];
 
+            // not special, so just return it
             if ('%' != c) {
                 decoded[output++] = c;
                 input += 1;
                 continue;
             }
 
-            uint16 byte1 = ([self diff_digit16:[percentEncoded characterAtIndex:(input+1)]] << 4) +
-                            [self diff_digit16:[percentEncoded characterAtIndex:(input+2)]];
+            NSUInteger byte1 = ([self diff_digit16:[percentEncoded characterAtIndex:(input+1)]] << 4) +
+                                [self diff_digit16:[percentEncoded characterAtIndex:(input+2)]];
 
+            // single-byte UTF-8 first byte has bitmask 0xxx xxxx
             if ((byte1 & 0x80) == 0) {
                 decoded[output++] = byte1;
                 input += 3;
                 continue;
             }
 
+            // at least one continuation byte
             if ('%' != [percentEncoded characterAtIndex:(input + 3)]) {
                 return nil;
             }
 
-            uint16 byte2 = ([self diff_digit16:[percentEncoded characterAtIndex:(input+4)]] << 4) +
-                            [self diff_digit16:[percentEncoded characterAtIndex:(input+5)]];
+            NSUInteger byte2 = ([self diff_digit16:[percentEncoded characterAtIndex:(input+4)]] << 4) +
+                                [self diff_digit16:[percentEncoded characterAtIndex:(input+5)]];
 
+            // continuation bytes have bitmask 10xx xxxx
             if ((byte2 & 0xC0) != 0x80) {
                 return nil;
             }
 
+            // continuation bytes thus only contribute six bits each
+            // these data bits are found with the bit mask xx11 1111
             byte2 = byte2 & 0x3F;
 
+            // in two-byte sequences the first byte has bitmask 110x xxxx
             if ((byte1 & 0xE0) == 0xC0) {
+                // byte1 ___x xxxx << 6
+                // byte2        __yy yyyy
+                // value    x xxxxyy yyyy -> 11 bits
                 decoded[output++] = ((byte1 & 0x1F) << 6) | byte2;
                 input += 6;
                 continue;
             }
 
+            // at least two continuation bytes
             if ('%' != [percentEncoded characterAtIndex:(input + 6)]) {
                 return nil;
             }
 
-            uint16 byte3 = ([self diff_digit16:[percentEncoded characterAtIndex:(input+7)]] << 4) +
-                            [self diff_digit16:[percentEncoded characterAtIndex:(input+8)]];
+            NSUInteger byte3 = ([self diff_digit16:[percentEncoded characterAtIndex:(input+7)]] << 4) +
+                                [self diff_digit16:[percentEncoded characterAtIndex:(input+8)]];
 
             if ((byte3 & 0xC0) != 0x80) {
                 return nil;
@@ -1423,18 +1444,24 @@ - (NSString *)diff_decodeURIWithText:(NSString *)percentEncoded
 
             byte3 = byte3 & 0x3F;
 
+            // in three-byte sequences the first byte has bitmask 1110 xxxx
             if ((byte1 & 0xF0) == 0xE0) {
+                // byte1 ____ xxxx << 12
+                // byte2        __yy yyyy << 6
+                // byte3               __zz zzzz
+                // value      xxxxyy yyyyzz zzzz -> 16 bits
                 decoded[output++] = ((byte1 & 0x0F) << 12) | (byte2 << 6) | byte3;
                 input += 9;
                 continue;
             }
 
+            // three continuation bytes
             if ('%' != [percentEncoded characterAtIndex:(input + 9)]) {
                 return nil;
             }
 
-            uint16 byte4 = ([self diff_digit16:[percentEncoded characterAtIndex:(input+10)]] << 4) +
-                            [self diff_digit16:[percentEncoded characterAtIndex:(input+11)]];
+            NSUInteger byte4 = ([self diff_digit16:[percentEncoded characterAtIndex:(input+10)]] << 4) +
+                                [self diff_digit16:[percentEncoded characterAtIndex:(input+11)]];
 
             if ((byte4 & 0xC0) != 0x80) {
                 return nil;
@@ -1442,8 +1469,14 @@ - (NSString *)diff_decodeURIWithText:(NSString *)percentEncoded
 
             byte4 = byte4 & 0x3F;
 
+            // in four-byte sequences the first byte has bitmask 1111 0xxx
             if ((byte1 & 0xF8) == 0xF0) {
-                uint32 codePoint = ((byte1 & 0x07) << 0x12) | (byte2 << 0x0C) | (byte3 << 0x06) | byte4;
+                // byte1 ____ _xxx << 18
+                // byte2        __yy yyyy << 12
+                // byte3               __zz zzzz << 6
+                // byte4                      __tt tttt
+                // value       xxxyy yyyyzz zzzztt tttt -> 21 bits
+                NSUInteger codePoint = ((byte1 & 0x07) << 0x12) | (byte2 << 0x0C) | (byte3 << 0x06) | byte4;
                 if (codePoint >= 0x010000 && codePoint <= 0x10FFFF) {
                     codePoint -= 0x010000;
                     decoded[output++] = ((codePoint >> 10) & 0x3FF) | 0xD800;

From 19606f083c2858bd5ee5d0f3585db5d310cc5104 Mon Sep 17 00:00:00 2001
From: Dennis Snell <dennis.snell@automattic.com>
Date: Thu, 19 Dec 2019 14:24:41 -0700
Subject: [PATCH 31/34] ObjectiveC: Guard against
 high-surrogate(null)low-surrogate

---
 objectivec/DiffMatchPatch.m           | 20 ++++++++++++++++++--
 objectivec/Tests/DiffMatchPatchTest.m |  4 ++++
 2 files changed, 22 insertions(+), 2 deletions(-)

diff --git a/objectivec/DiffMatchPatch.m b/objectivec/DiffMatchPatch.m
index 98455af..ff1ba19 100755
--- a/objectivec/DiffMatchPatch.m
+++ b/objectivec/DiffMatchPatch.m
@@ -1492,8 +1492,24 @@ - (NSString *)diff_decodeURIWithText:(NSString *)percentEncoded
     @catch (NSException *e) {
         return nil;
     }
-    
-    return [NSString stringWithCharacters:decoded length:output];
+
+    // some objective-c versions of the library produced patches with
+    // (null) in the place where surrogates were split across diff
+    // boundaries. if we leave those in we'll be stuck with a
+    // high-surrogate (null) low-surrogate pattern that will break
+    // deeper in the library or consumping application. we'll "fix"
+    // these by dropping the (null) and re-joining the surrogate halves
+    NSString *result = [NSString stringWithCharacters:decoded length:output];
+    NSRegularExpression *replacer = [NSRegularExpression
+                                     regularExpressionWithPattern:@"([\\x{D800}-\\x{DBFF}])\\(null\\)([\\x{DC00}-\\x{DFFF}])"
+                                     options:0
+                                     error:nil];
+
+    return [replacer
+            stringByReplacingMatchesInString:result
+            options:0
+            range:NSMakeRange(0, [result length])
+            withTemplate:@"$1$2"];
 }
 
 /**
diff --git a/objectivec/Tests/DiffMatchPatchTest.m b/objectivec/Tests/DiffMatchPatchTest.m
index 7e31508..6978908 100755
--- a/objectivec/Tests/DiffMatchPatchTest.m
+++ b/objectivec/Tests/DiffMatchPatchTest.m
@@ -814,6 +814,10 @@ - (void)test_diff_deltaTest {
                                             [Diff diffWithOperation:DIFF_INSERT andText:[NSString stringWithFormat:@"%C", 0xdd71]],
                                             nil])]);
 
+    // Invalid diff from objective-c with (null) string
+    XCTAssertEqualObjects([dmp diff_fromDeltaWithText:@"" andDelta:@"+%ED%A0%BC%28null%29%ED%B5%B0" error:nil],
+                          ([NSMutableArray arrayWithObjects:[Diff diffWithOperation:DIFF_INSERT andText:@"🅰"],nil]));
+
   // Verify pool of unchanged characters.
   diffs = [NSMutableArray arrayWithObject:
        [Diff diffWithOperation:DIFF_INSERT andText:@"A-Z a-z 0-9 - _ . ! ~ * ' ( ) ; / ? : @ & = + $ , # "]];

From 477b5a669d396f68b5dc66e778cc54ff5026fa2e Mon Sep 17 00:00:00 2001
From: Dennis Snell <dennis.snell@automattic.com>
Date: Thu, 19 Dec 2019 14:26:59 -0700
Subject: [PATCH 32/34] Fix typo

---
 javascript/diff_match_patch_uncompressed.js | 2 +-
 objectivec/DiffMatchPatch.m                 | 2 +-
 2 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/javascript/diff_match_patch_uncompressed.js b/javascript/diff_match_patch_uncompressed.js
index 2b93ecc..8101847 100644
--- a/javascript/diff_match_patch_uncompressed.js
+++ b/javascript/diff_match_patch_uncompressed.js
@@ -1516,7 +1516,7 @@ diff_match_patch.prototype.decodeURI = function(text) {
     // (null) in the place where surrogates were split across diff
     // boundaries. if we leave those in we'll be stuck with a
     // high-surrogate (null) low-surrogate pattern that will break
-    // deeper in the library or consumping application. we'll "fix"
+    // deeper in the library or consuming application. we'll "fix"
     // these by dropping the (null) and re-joining the surrogate halves
     return decoded.replace(/([\uD800-\uDBFF])\(null\)([\uDC00-\uDFFF])/g, "$1$2");
   }
diff --git a/objectivec/DiffMatchPatch.m b/objectivec/DiffMatchPatch.m
index ff1ba19..0c56201 100755
--- a/objectivec/DiffMatchPatch.m
+++ b/objectivec/DiffMatchPatch.m
@@ -1497,7 +1497,7 @@ - (NSString *)diff_decodeURIWithText:(NSString *)percentEncoded
     // (null) in the place where surrogates were split across diff
     // boundaries. if we leave those in we'll be stuck with a
     // high-surrogate (null) low-surrogate pattern that will break
-    // deeper in the library or consumping application. we'll "fix"
+    // deeper in the library or consuming application. we'll "fix"
     // these by dropping the (null) and re-joining the surrogate halves
     NSString *result = [NSString stringWithCharacters:decoded length:output];
     NSRegularExpression *replacer = [NSRegularExpression

From fa122d3dfef5359f5af3535ed754083c6f16578e Mon Sep 17 00:00:00 2001
From: Dennis Snell <dennis.snell@automattic.com>
Date: Thu, 19 Dec 2019 14:34:48 -0700
Subject: [PATCH 33/34] Java: Use StringBuildler in decodeURI and guard against
 H(null)L pattern

---
 .../fraser/neil/plaintext/diff_match_patch.java     | 13 +++++++++++--
 .../neil/plaintext/diff_match_patch_test.java       |  6 ++++++
 2 files changed, 17 insertions(+), 2 deletions(-)

diff --git a/java/src/name/fraser/neil/plaintext/diff_match_patch.java b/java/src/name/fraser/neil/plaintext/diff_match_patch.java
index 9f3f71e..71e6480 100644
--- a/java/src/name/fraser/neil/plaintext/diff_match_patch.java
+++ b/java/src/name/fraser/neil/plaintext/diff_match_patch.java
@@ -1507,7 +1507,7 @@ private int digit16(char b) throws IllegalArgumentException {
 
   private String decodeURI(String text) throws IllegalArgumentException {
     int i = 0;
-    StringBuffer decoded = new StringBuffer("");
+    StringBuilder decoded = new StringBuilder(text.length());
 
     while (i < text.length()) {
       if (text.charAt(i) != '%') {
@@ -1576,7 +1576,16 @@ private String decodeURI(String text) throws IllegalArgumentException {
       throw new IllegalArgumentException();
     }
 
-    return decoded.toString();
+    // some objective-c versions of the library produced patches with
+    // (null) in the place where surrogates were split across diff
+    // boundaries. if we leave those in we'll be stuck with a
+    // high-surrogate (null) low-surrogate pattern that will break
+    // deeper in the library or consuming application. we'll "fix"
+    // these by dropping the (null) and re-joining the surrogate halves
+    return decoded.toString().replaceAll(
+      "([\\uD800-\\uDBFF])\\(null\\)([\\uDC00-\\uDFFF])",
+      "$1$2"
+    );
   }
 
   /**
diff --git a/java/tests/name/fraser/neil/plaintext/diff_match_patch_test.java b/java/tests/name/fraser/neil/plaintext/diff_match_patch_test.java
index 5be10f1..04aa860 100644
--- a/java/tests/name/fraser/neil/plaintext/diff_match_patch_test.java
+++ b/java/tests/name/fraser/neil/plaintext/diff_match_patch_test.java
@@ -460,6 +460,12 @@ public static void testDiffDelta() {
       dmp.diff_toDelta(dmp.diff_fromDelta("\ud83c\udd70", "=1\t-1\t+%ED%B5%B1"))
     );
 
+    assertEquals(
+      "diff_fromDelta: Invalid diff from objective-c with (null) string",
+      diffList(new Diff(INSERT, "\ud83c\udd70")),
+      dmp.diff_fromDelta("", "+%ED%A0%BC%28null%29%ED%B5%B0")
+    );
+
     // Verify pool of unchanged characters.
     diffs = diffList(new Diff(INSERT, "A-Z a-z 0-9 - _ . ! ~ * ' ( ) ; / ? : @ & = + $ , # "));
     String text2 = dmp.diff_text2(diffs);

From 21aebb404b5af9050ceaeb518cf9a352688ce620 Mon Sep 17 00:00:00 2001
From: Dennis Snell <dennis.snell@automattic.com>
Date: Tue, 14 Jan 2020 20:10:18 -0700
Subject: [PATCH 34/34] Remove attempt at fixing the (null) bug

---
 .../name/fraser/neil/plaintext/diff_match_patch.java  | 11 +----------
 .../fraser/neil/plaintext/diff_match_patch_test.java  |  6 ------
 javascript/diff_match_patch.js                        | 10 +++++-----
 javascript/diff_match_patch_uncompressed.js           |  9 +--------
 javascript/tests/diff_match_patch_test.js             | 11 +----------
 objectivec/Tests/DiffMatchPatchTest.m                 |  4 ----
 6 files changed, 8 insertions(+), 43 deletions(-)

diff --git a/java/src/name/fraser/neil/plaintext/diff_match_patch.java b/java/src/name/fraser/neil/plaintext/diff_match_patch.java
index 71e6480..fe5b55d 100644
--- a/java/src/name/fraser/neil/plaintext/diff_match_patch.java
+++ b/java/src/name/fraser/neil/plaintext/diff_match_patch.java
@@ -1576,16 +1576,7 @@ private String decodeURI(String text) throws IllegalArgumentException {
       throw new IllegalArgumentException();
     }
 
-    // some objective-c versions of the library produced patches with
-    // (null) in the place where surrogates were split across diff
-    // boundaries. if we leave those in we'll be stuck with a
-    // high-surrogate (null) low-surrogate pattern that will break
-    // deeper in the library or consuming application. we'll "fix"
-    // these by dropping the (null) and re-joining the surrogate halves
-    return decoded.toString().replaceAll(
-      "([\\uD800-\\uDBFF])\\(null\\)([\\uDC00-\\uDFFF])",
-      "$1$2"
-    );
+    return decoded.toString();
   }
 
   /**
diff --git a/java/tests/name/fraser/neil/plaintext/diff_match_patch_test.java b/java/tests/name/fraser/neil/plaintext/diff_match_patch_test.java
index 04aa860..5be10f1 100644
--- a/java/tests/name/fraser/neil/plaintext/diff_match_patch_test.java
+++ b/java/tests/name/fraser/neil/plaintext/diff_match_patch_test.java
@@ -460,12 +460,6 @@ public static void testDiffDelta() {
       dmp.diff_toDelta(dmp.diff_fromDelta("\ud83c\udd70", "=1\t-1\t+%ED%B5%B1"))
     );
 
-    assertEquals(
-      "diff_fromDelta: Invalid diff from objective-c with (null) string",
-      diffList(new Diff(INSERT, "\ud83c\udd70")),
-      dmp.diff_fromDelta("", "+%ED%A0%BC%28null%29%ED%B5%B0")
-    );
-
     // Verify pool of unchanged characters.
     diffs = diffList(new Diff(INSERT, "A-Z a-z 0-9 - _ . ! ~ * ' ( ) ; / ? : @ & = + $ , # "));
     String text2 = dmp.diff_text2(diffs);
diff --git a/javascript/diff_match_patch.js b/javascript/diff_match_patch.js
index 37bd784..8f33865 100644
--- a/javascript/diff_match_patch.js
+++ b/javascript/diff_match_patch.js
@@ -28,11 +28,11 @@ diff_match_patch.prototype.diff_xIndex=function(a,b){var d=0,c=0,e=0,f=0,g;for(g
 diff_match_patch.prototype.diff_prettyHtml=function(a){for(var b=[],d=/&/g,c=/</g,e=/>/g,f=/\n/g,g=0;g<a.length;g++){var h=a[g][0],l=a[g][1].replace(d,"&amp;").replace(c,"&lt;").replace(e,"&gt;").replace(f,"&para;<br>");switch(h){case DIFF_INSERT:b[g]='<ins style="background:#e6ffe6;">'+l+"</ins>";break;case DIFF_DELETE:b[g]='<del style="background:#ffe6e6;">'+l+"</del>";break;case DIFF_EQUAL:b[g]="<span>"+l+"</span>"}}return b.join("")};
 diff_match_patch.prototype.diff_text1=function(a){for(var b=[],d=0;d<a.length;d++)a[d][0]!==DIFF_INSERT&&(b[d]=a[d][1]);return b.join("")};diff_match_patch.prototype.diff_text2=function(a){for(var b=[],d=0;d<a.length;d++)a[d][0]!==DIFF_DELETE&&(b[d]=a[d][1]);return b.join("")};
 diff_match_patch.prototype.diff_levenshtein=function(a){for(var b=0,d=0,c=0,e=0;e<a.length;e++){var f=a[e][1];switch(a[e][0]){case DIFF_INSERT:d+=f.length;break;case DIFF_DELETE:c+=f.length;break;case DIFF_EQUAL:b+=Math.max(d,c),c=d=0}}return b+=Math.max(d,c)};diff_match_patch.prototype.isHighSurrogate=function(a){a=a.charCodeAt(0);return 55296<=a&&56319>=a};diff_match_patch.prototype.isLowSurrogate=function(a){a=a.charCodeAt(0);return 56320<=a&&57343>=a};
-diff_match_patch.prototype.diff_toDelta=function(a){for(var b=[],d,c=0;c<a.length;c++){var e=a[c],f=e[1][0],g=e[1][e[1].length-1];if(0!==e[1].length&&(g&&this.isHighSurrogate(g)&&(d=g,e[1]=e[1].slice(0,-1)),d&&f&&this.isHighSurrogate(d)&&this.isLowSurrogate(f)&&(e[1]=d+e[1]),DIFF_EQUAL===e[0]&&(d=g),0!==e[1].length))switch(e[0]){case DIFF_INSERT:b.push("+"+encodeURI(e[1]));break;case DIFF_DELETE:b.push("-"+e[1].length);break;case DIFF_EQUAL:b.push("="+e[1].length)}}return b.join("\t").replace(/%20/g,
-" ")};
-diff_match_patch.prototype.decodeURI=function(a){try{return decodeURI(a)}catch(h){for(var b=0,d="";b<a.length;)if("%"!==a[b])d+=a[b++];else{var c=parseInt(a.substring(b+1,b+3),16);if(0===(c&128))d+=String.fromCharCode(c),b+=3;else{if("%"!==a[b+3])throw new URIError("URI malformed");var e=parseInt(a.substring(b+4,b+6),16);if(128!==(e&192))throw new URIError("URI malformed");e&=63;if(192===(c&224))d+=String.fromCharCode((c&31)<<6|e),b+=6;else{if("%"!==a[b+6])throw new URIError("URI malformed");var f=
-parseInt(a.substring(b+7,b+9),16);if(128!==(f&192))throw new URIError("URI malformed");f&=63;if(224===(c&240))d+=String.fromCharCode((c&15)<<12|e<<6|f),b+=9;else{if("%"!==a[b+9])throw new URIError("URI malformed");var g=parseInt(a.substring(b+10,b+12),16);if(128!==(g&192))throw new URIError("URI malformed");g&=63;if(240===(c&248)&&(c=(c&7)<<18|e<<12|f<<6|g,65536<=c&&1114111>=c)){d+=String.fromCharCode((c&65535)>>>10&1023|55296);d+=String.fromCharCode(56320|c&1023);b+=12;continue}throw new URIError("URI malformed");
-}}}}return d}};
+diff_match_patch.prototype.diff_toDelta=function(a){for(var b=[],d,c=0;c<a.length;c++){var e=a[c],f=e[1][0],g=e[1][e[1].length-1];if(0!==e[1].length&&(g&&this.isHighSurrogate(g)&&(d=g,e[1]=e[1].slice(0,-1)),d&&f&&this.isHighSurrogate(d)&&this.isLowSurrogate(f)&&(e[1]=d+e[1]),0!==e[1].length))switch(e[0]){case DIFF_INSERT:b.push("+"+encodeURI(e[1]));break;case DIFF_DELETE:b.push("-"+e[1].length);break;case DIFF_EQUAL:b.push("="+e[1].length)}}return b.join("\t").replace(/%20/g," ")};
+diff_match_patch.prototype.digit16=function(a){switch(a){case "0":return 0;case "1":return 1;case "2":return 2;case "3":return 3;case "4":return 4;case "5":return 5;case "6":return 6;case "7":return 7;case "8":return 8;case "9":return 9;case "A":case "a":return 10;case "B":case "b":return 11;case "C":case "c":return 12;case "D":case "d":return 13;case "E":case "e":return 14;case "F":case "f":return 15;default:throw Error("Invalid hex-code");}};
+diff_match_patch.prototype.decodeURI=function(a){try{return decodeURI(a)}catch(h){for(var b=0,d="";b<a.length;)if("%"!==a[b])d+=a[b++];else{var c=(this.digit16(a[b+1])<<4)+this.digit16(a[b+2]);if(0===(c&128))d+=String.fromCharCode(c),b+=3;else{if("%"!==a[b+3])throw new URIError("URI malformed");var e=(this.digit16(a[b+4])<<4)+this.digit16(a[b+5]);if(128!==(e&192))throw new URIError("URI malformed");e&=63;if(192===(c&224))d+=String.fromCharCode((c&31)<<6|e),b+=6;else{if("%"!==a[b+6])throw new URIError("URI malformed");
+var f=(this.digit16(a[b+7])<<4)+this.digit16(a[b+8]);if(128!==(f&192))throw new URIError("URI malformed");f&=63;if(224===(c&240))d+=String.fromCharCode((c&15)<<12|e<<6|f),b+=9;else{if("%"!==a[b+9])throw new URIError("URI malformed");var g=(this.digit16(a[b+10])<<4)+this.digit16(a[b+11]);if(128!==(g&192))throw new URIError("URI malformed");g&=63;if(240===(c&248)&&(c=(c&7)<<18|e<<12|f<<6|g,65536<=c&&1114111>=c)){d+=String.fromCharCode((c&65535)>>>10&1023|55296);d+=String.fromCharCode(56320|c&1023);
+b+=12;continue}throw new URIError("URI malformed");}}}}return d}};
 diff_match_patch.prototype.diff_fromDelta=function(a,b){for(var d=[],c=0,e=0,f=b.split(/\t/g),g=0;g<f.length;g++){var h=f[g].substring(1);switch(f[g].charAt(0)){case "+":try{d[c++]=new diff_match_patch.Diff(DIFF_INSERT,this.decodeURI(h))}catch(k){throw Error("Illegal escape in diff_fromDelta: "+h);}break;case "-":case "=":var l=parseInt(h,10);if(isNaN(l)||0>l)throw Error("Invalid number in diff_fromDelta: "+h);h=a.substring(e,e+=l);"="==f[g].charAt(0)?d[c++]=new diff_match_patch.Diff(DIFF_EQUAL,h):
 d[c++]=new diff_match_patch.Diff(DIFF_DELETE,h);break;default:if(f[g])throw Error("Invalid diff operation in diff_fromDelta: "+f[g]);}}if(e!=a.length)throw Error("Delta length ("+e+") does not equal source text length ("+a.length+").");return d};diff_match_patch.prototype.match_main=function(a,b,d){if(null==a||null==b||null==d)throw Error("Null input. (match_main)");d=Math.max(0,Math.min(d,a.length));return a==b?0:a.length?a.substring(d,d+b.length)==b?d:this.match_bitap_(a,b,d):-1};
 diff_match_patch.prototype.match_bitap_=function(a,b,d){function c(a,c){var e=a/b.length,g=Math.abs(d-c);return f.Match_Distance?e+g/f.Match_Distance:g?1:e}if(b.length>this.Match_MaxBits)throw Error("Pattern too long for this browser.");var e=this.match_alphabet_(b),f=this,g=this.Match_Threshold,h=a.indexOf(b,d);-1!=h&&(g=Math.min(c(0,h),g),h=a.lastIndexOf(b,d+b.length),-1!=h&&(g=Math.min(c(0,h),g)));var l=1<<b.length-1;h=-1;for(var k,m,p=b.length+a.length,x,w=0;w<b.length;w++){k=0;for(m=p;k<m;)c(w,
diff --git a/javascript/diff_match_patch_uncompressed.js b/javascript/diff_match_patch_uncompressed.js
index 8101847..3d112e8 100644
--- a/javascript/diff_match_patch_uncompressed.js
+++ b/javascript/diff_match_patch_uncompressed.js
@@ -1361,7 +1361,6 @@ diff_match_patch.prototype.diff_toDelta = function(diffs) {
   var text = [];
   var lastEnd;
   for (var x = 0; x < diffs.length; x++) {
-
     var thisDiff = diffs[x];
     var thisTop = thisDiff[1][0];
     var thisEnd = thisDiff[1][thisDiff[1].length - 1];
@@ -1512,13 +1511,7 @@ diff_match_patch.prototype.decodeURI = function(text) {
       throw new URIError('URI malformed');
     }
 
-    // some objective-c versions of the library produced patches with
-    // (null) in the place where surrogates were split across diff
-    // boundaries. if we leave those in we'll be stuck with a
-    // high-surrogate (null) low-surrogate pattern that will break
-    // deeper in the library or consuming application. we'll "fix"
-    // these by dropping the (null) and re-joining the surrogate halves
-    return decoded.replace(/([\uD800-\uDBFF])\(null\)([\uDC00-\uDFFF])/g, "$1$2");
+    return decoded;
   }
 };
 
diff --git a/javascript/tests/diff_match_patch_test.js b/javascript/tests/diff_match_patch_test.js
index 9ea1c6e..99aaca1 100644
--- a/javascript/tests/diff_match_patch_test.js
+++ b/javascript/tests/diff_match_patch_test.js
@@ -546,7 +546,7 @@ function testDiffDelta() {
 
     for(let i = 0; i < 1000; i++) {
       newText = applyRandomTextEdit(originalText);
-      dmp.patch_toText(dmp.patch_make(originalText, newText));
+      dmp.diff_toDelta(dmp.diff_main(originalText, newText));
     }
   })();
 
@@ -605,15 +605,6 @@ function testDiffDelta() {
     assertEquals('Swap surrogate pair', 'crashed');
   }
 
-  try {
-    assertEquivalent(
-      dmp.diff_fromDelta('', '+%ED%A0%BC%28null%29%ED%B5%B0'),
-      [[DIFF_INSERT, '\ud83c\udd70']]
-    );
-  } catch ( e ) {
-    assertEquals('Invalid diff from objective-c with (null) string' );
-  }
-
   // Empty diff groups
   assertEquivalent(
     dmp.diff_toDelta([[DIFF_EQUAL, 'abcdef'], [DIFF_DELETE, ''], [DIFF_INSERT, 'ghijk']]),
diff --git a/objectivec/Tests/DiffMatchPatchTest.m b/objectivec/Tests/DiffMatchPatchTest.m
index 6978908..7e31508 100755
--- a/objectivec/Tests/DiffMatchPatchTest.m
+++ b/objectivec/Tests/DiffMatchPatchTest.m
@@ -814,10 +814,6 @@ - (void)test_diff_deltaTest {
                                             [Diff diffWithOperation:DIFF_INSERT andText:[NSString stringWithFormat:@"%C", 0xdd71]],
                                             nil])]);
 
-    // Invalid diff from objective-c with (null) string
-    XCTAssertEqualObjects([dmp diff_fromDeltaWithText:@"" andDelta:@"+%ED%A0%BC%28null%29%ED%B5%B0" error:nil],
-                          ([NSMutableArray arrayWithObjects:[Diff diffWithOperation:DIFF_INSERT andText:@"🅰"],nil]));
-
   // Verify pool of unchanged characters.
   diffs = [NSMutableArray arrayWithObject:
        [Diff diffWithOperation:DIFF_INSERT andText:@"A-Z a-z 0-9 - _ . ! ~ * ' ( ) ; / ? : @ & = + $ , # "]];