includes/clientside/tinymce/plugins/devkit/jscripts/diff.js
changeset 1 fe660c52c48f
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/includes/clientside/tinymce/plugins/devkit/jscripts/diff.js	Wed Jun 13 16:07:17 2007 -0400
@@ -0,0 +1,1192 @@
+// Diff_Match_Patch v1.3
+// Computes the difference between two texts to create a patch.
+// Applies the patch onto another text, allowing for errors.
+// Copyright (C) 2006 Neil Fraser
+// http://neil.fraser.name/software/diff_match_patch/
+
+// This program is free software; you can redistribute it and/or
+// modify it under the terms of the GNU General Public License
+// as published by the Free Software Foundation.
+
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License (www.gnu.org) for more details.
+
+
+// Constants.
+// Redefine these in your program to override the defaults.
+
+// Number of seconds to map a diff before giving up.  (0 for infinity)
+var DIFF_TIMEOUT = 1.0;
+// Cost of an empty edit operation in terms of edit characters.
+var DIFF_EDIT_COST = 4;
+// Tweak the relative importance (0.0 = accuracy, 1.0 = proximity)
+var MATCH_BALANCE = 0.5;
+// At what point is no match declared (0.0 = perfection, 1.0 = very loose)
+var MATCH_THRESHOLD = 0.5;
+// The min and max cutoffs used when computing text lengths.
+var MATCH_MINLENGTH = 100;
+var MATCH_MAXLENGTH = 1000;
+// Chunk size for context length.
+var PATCH_MARGIN = 4;
+
+
+  //////////////////////////////////////////////////////////////////////
+ //  Diff                                                            //
+//////////////////////////////////////////////////////////////////////
+
+// The data structure representing a diff is an array of tuples:
+// [[-1, "Hello"], [1, "Goodbye"], [0, " world."]]
+// which means: delete "Hello", add "Goodbye" and keep " world."
+
+
+function diff_main(text1, text2, checklines) {
+  // Find the differences between two texts.  Return an array of changes.
+  // If checklines is present and false, then don't run a line-level diff first to identify the changed areas.
+  // Check for equality (speedup)
+  if (text1 == text2)
+    return [[0, text1]];
+
+  if (typeof checklines == 'undefined')
+    checklines = true;
+
+  var a;
+  // Trim off common prefix (speedup)
+  a = diff_prefix(text1, text2);
+  text1 = a[0];
+  text2 = a[1];
+  var commonprefix = a[2];
+
+  // Trim off common suffix (speedup)
+  a = diff_suffix(text1, text2);
+  text1 = a[0];
+  text2 = a[1];
+  var commonsuffix = a[2];
+
+  var diff, i;
+  var longtext = text1.length > text2.length ? text1 : text2;
+  var shorttext = text1.length > text2.length ? text2 : text1;
+
+  if (!text1) {  // Just add some text (speedup)
+    diff = [[1, text2]];
+  } else if (!text2) { // Just delete some text (speedup)
+    diff = [[-1, text1]];
+  } else if ((i = longtext.indexOf(shorttext)) != -1) {
+    // Shorter text is inside the longer text (speedup)
+    diff = [[1, longtext.substring(0, i)], [0, shorttext], [1, longtext.substring(i+shorttext.length)]];
+    // Swap insertions for deletions if diff is reversed.
+    if (text1.length > text2.length)
+      diff[0][0] = diff[2][0] = -1;
+  } else {
+    longtext = shorttext = null; // Garbage collect
+    // Check to see if the problem can be split in two.
+    var hm = diff_halfmatch(text1, text2);
+    if (hm) {
+      // A half-match was found, sort out the return data.
+      var text1_a = hm[0];
+      var text1_b = hm[1];
+      var text2_a = hm[2];
+      var text2_b = hm[3];
+      var mid_common = hm[4];
+      // Send both pairs off for separate processing.
+      var diff_a = diff_main(text1_a, text2_a, checklines);
+      var diff_b = diff_main(text1_b, text2_b, checklines);
+      // Merge the results.
+      diff = diff_a.concat([[0, mid_common]], diff_b);
+    } else {
+      // Perform a real diff.
+      if (checklines && text1.length + text2.length < 250)
+        checklines = false; // Too trivial for the overhead.
+      if (checklines) {
+        // Scan the text on a line-by-line basis first.
+        a = diff_lines2chars(text1, text2);
+        text1 = a[0];
+        text2 = a[1];
+        var linearray = a[2];
+      }
+      diff = diff_map(text1, text2);
+      if (!diff) // No acceptable result.
+        diff = [[-1, text1], [1, text2]];
+      if (checklines) {
+        diff_chars2lines(diff, linearray); // Convert the diff back to original text.
+        diff_cleanup_semantic(diff); // Eliminate freak matches (e.g. blank lines)
+
+        // Rediff any replacement blocks, this time on character-by-character basis.
+        diff.push([0, '']);  // Add a dummy entry at the end.
+        var pointer = 0;
+        var count_delete = 0;
+        var count_insert = 0;
+        var text_delete = '';
+        var text_insert = '';
+        while(pointer < diff.length) {
+          if (diff[pointer][0] == 1) {
+            count_insert++;
+            text_insert += diff[pointer][1];
+          } else if (diff[pointer][0] == -1) {
+            count_delete++;
+            text_delete += diff[pointer][1];
+          } else {  // Upon reaching an equality, check for prior redundancies.
+            if (count_delete >= 1 && count_insert >= 1) {
+              // Delete the offending records and add the merged ones.
+              a = diff_main(text_delete, text_insert, false);
+              diff.splice(pointer - count_delete - count_insert, count_delete + count_insert);
+              pointer = pointer - count_delete - count_insert;
+              for (i=a.length-1; i>=0; i--)
+                diff.splice(pointer, 0, a[i]);
+              pointer = pointer + a.length;
+            }
+            count_insert = 0;
+            count_delete = 0;
+            text_delete = '';
+            text_insert = '';
+          }
+          pointer++;
+        }
+        diff.pop();  // Remove the dummy entry at the end.
+
+      }
+    }
+  }
+
+  if (commonprefix)
+    diff.unshift([0, commonprefix]);
+  if (commonsuffix)
+    diff.push([0, commonsuffix]);
+  diff_cleanup_merge(diff);
+  return diff;
+}
+
+
+function diff_lines2chars(text1, text2) {
+  // Split text into an array of strings.
+  // Reduce the texts to a string of hashes where each character represents one line.
+  var linearray = new Array();  // linearray[4] == "Hello\n"
+  var linehash = new Object();  // linehash["Hello\n"] == 4
+
+  // "\x00" is a valid JavaScript character, but the Venkman debugger doesn't like it (bug 335098)
+  // So we'll insert a junk entry to avoid generating a null character.
+  linearray.push('');
+
+  function diff_lines2chars_munge(text) {
+    // My first ever closure!
+    var i, line;
+    var chars = '';
+    while (text) {
+      i = text.indexOf('\n');
+      if (i == -1)
+        i = text.length;
+      line = text.substring(0, i+1);
+      text = text.substring(i+1);
+      if (linehash.hasOwnProperty ? linehash.hasOwnProperty(line) : (linehash[line] !== undefined)) {
+        chars += String.fromCharCode(linehash[line]);
+      } else {
+        linearray.push(line);
+        linehash[line] = linearray.length - 1;
+        chars += String.fromCharCode(linearray.length - 1);
+      }
+    }
+    return chars;
+  }
+
+  var chars1 = diff_lines2chars_munge(text1);
+  var chars2 = diff_lines2chars_munge(text2);
+  return [chars1, chars2, linearray];
+}
+
+
+function diff_chars2lines(diff, linearray) {
+  // Rehydrate the text in a diff from a string of line hashes to real lines of text.
+  var chars, text;
+  for (var x=0; x<diff.length; x++) {
+    chars = diff[x][1];
+    text = '';
+    for (var y=0; y<chars.length; y++)
+      text += linearray[chars.charCodeAt(y)];
+    diff[x][1] = text;
+  }
+}
+
+
+function diff_map(text1, text2) {
+  // Explore the intersection points between the two texts.
+  var now = new Date();
+  var ms_end = now.getTime() + DIFF_TIMEOUT * 1000; // Don't run for too long.
+  var max = (text1.length + text2.length) / 2;
+  var v_map1 = new Array();
+  var v_map2 = new Array();
+  var v1 = new Object();
+  var v2 = new Object();
+  v1[1] = 0;
+  v2[1] = 0;
+  var x, y;
+  var footstep; // Used to track overlapping paths.
+  var footsteps = new Object();
+  var done = false;
+  var hasOwnProperty = !!(footsteps.hasOwnProperty);
+  // If the total number of characters is odd, then the front path will collide with the reverse path.
+  var front = (text1.length + text2.length) % 2;
+  for (var d=0; d<max; d++) {
+    now = new Date();
+    if (DIFF_TIMEOUT > 0 && now.getTime() > ms_end) // Timeout reached
+      return null;
+
+    // Walk the front path one step.
+    v_map1[d] = new Object();
+    for (var k=-d; k<=d; k+=2) {
+      if (k == -d || k != d && v1[k-1] < v1[k+1])
+        x = v1[k+1];
+      else
+        x = v1[k-1]+1;
+      y = x - k;
+      footstep = x+","+y;
+      if (front && (hasOwnProperty ? footsteps.hasOwnProperty(footstep) : (footsteps[footstep] !== undefined)))
+        done = true;
+      if (!front)
+        footsteps[footstep] = d;
+      while (!done && x < text1.length && y < text2.length && text1.charAt(x) == text2.charAt(y)) {
+        x++; y++;
+        footstep = x+","+y;
+        if (front && (hasOwnProperty ? footsteps.hasOwnProperty(footstep) : (footsteps[footstep] !== undefined)))
+          done = true;
+        if (!front)
+          footsteps[footstep] = d;
+      }
+      v1[k] = x;
+      v_map1[d][x+","+y] = true;
+      if (done) {
+        // Front path ran over reverse path.
+        v_map2 = v_map2.slice(0, footsteps[footstep]+1);
+        var a = diff_path1(v_map1, text1.substring(0, x), text2.substring(0, y));
+        return a.concat(diff_path2(v_map2, text1.substring(x), text2.substring(y)));
+      }
+    }
+
+    // Walk the reverse path one step.
+    v_map2[d] = new Object();
+    for (var k=-d; k<=d; k+=2) {
+      if (k == -d || k != d && v2[k-1] < v2[k+1])
+        x = v2[k+1];
+      else
+        x = v2[k-1]+1;
+      y = x - k;
+      footstep = (text1.length-x)+","+(text2.length-y);
+      if (!front && (hasOwnProperty ? footsteps.hasOwnProperty(footstep) : (footsteps[footstep] !== undefined)))
+        done = true;
+      if (front)
+        footsteps[footstep] = d;
+      while (!done && x < text1.length && y < text2.length && text1.charAt(text1.length-x-1) == text2.charAt(text2.length-y-1)) {
+        x++; y++;
+        footstep = (text1.length-x)+","+(text2.length-y);
+        if (!front && (hasOwnProperty ? footsteps.hasOwnProperty(footstep) : (footsteps[footstep] !== undefined)))
+          done = true;
+        if (front)
+          footsteps[footstep] = d;
+      }
+      v2[k] = x;
+      v_map2[d][x+","+y] = true;
+      if (done) {
+        // Reverse path ran over front path.
+        v_map1 = v_map1.slice(0, footsteps[footstep]+1);
+        var a = diff_path1(v_map1, text1.substring(0, text1.length-x), text2.substring(0, text2.length-y));
+        return a.concat(diff_path2(v_map2, text1.substring(text1.length-x), text2.substring(text2.length-y)));
+      }
+    }
+  }
+  // Number of diffs equals number of characters, no commonality at all.
+  return null;
+}
+
+
+function diff_path1(v_map, text1, text2) {
+  // Work from the middle back to the start to determine the path.
+  var path = [];
+  var x = text1.length;
+  var y = text2.length;
+  var last_op = null;
+  for (var d=v_map.length-2; d>=0; d--) {
+    while(1) {
+      if (v_map[d].hasOwnProperty ? v_map[d].hasOwnProperty((x-1)+","+y) : (v_map[d][(x-1)+","+y] !== undefined)) {
+        x--;
+        if (last_op === -1)
+          path[0][1] = text1.charAt(x) + path[0][1];
+        else
+          path.unshift([-1, text1.charAt(x)]);
+        last_op = -1;
+        break;
+      } else if (v_map[d].hasOwnProperty ? v_map[d].hasOwnProperty(x+","+(y-1)) : (v_map[d][x+","+(y-1)] !== undefined)) {
+        y--;
+        if (last_op === 1)
+          path[0][1] = text2.charAt(y) + path[0][1];
+        else
+          path.unshift([1, text2.charAt(y)]);
+        last_op = 1;
+        break;
+      } else {
+        x--;
+        y--;
+        //if (text1.charAt(x) != text2.charAt(y))
+        //  return alert("No diagonal.  Can't happen. (diff_path1)");
+        if (last_op === 0)
+          path[0][1] = text1.charAt(x) + path[0][1];
+        else
+          path.unshift([0, text1.charAt(x)]);
+        last_op = 0;
+      }
+    }
+  }
+  return path;
+}
+
+
+function diff_path2(v_map, text1, text2) {
+  // Work from the middle back to the end to determine the path.
+  var path = [];
+  var x = text1.length;
+  var y = text2.length;
+  var last_op = null;
+  for (var d=v_map.length-2; d>=0; d--) {
+    while(1) {
+      if (v_map[d].hasOwnProperty ? v_map[d].hasOwnProperty((x-1)+","+y) : (v_map[d][(x-1)+","+y] !== undefined)) {
+        x--;
+        if (last_op === -1)
+          path[path.length-1][1] += text1.charAt(text1.length-x-1);
+        else
+          path.push([-1, text1.charAt(text1.length-x-1)]);
+        last_op = -1;
+        break;
+      } else if (v_map[d].hasOwnProperty ? v_map[d].hasOwnProperty(x+","+(y-1)) : (v_map[d][x+","+(y-1)] !== undefined)) {
+        y--;
+        if (last_op === 1)
+          path[path.length-1][1] += text2.charAt(text2.length-y-1);
+        else
+          path.push([1, text2.charAt(text2.length-y-1)]);
+        last_op = 1;
+        break;
+      } else {
+        x--;
+        y--;
+        //if (text1.charAt(text1.length-x-1) != text2.charAt(text2.length-y-1))
+        //  return alert("No diagonal.  Can't happen. (diff_path2)");
+        if (last_op === 0)
+          path[path.length-1][1] += text1.charAt(text1.length-x-1);
+        else
+          path.push([0, text1.charAt(text1.length-x-1)]);
+        last_op = 0;
+      }
+    }
+  }
+  return path;
+}
+
+
+function diff_prefix(text1, text2) {
+  // Trim off common prefix
+  var pointermin = 0;
+  var pointermax = Math.min(text1.length, text2.length);
+  var pointermid = pointermax;
+  while(pointermin < pointermid) {
+    if (text1.substring(0, pointermid) == text2.substring(0, pointermid))
+      pointermin = pointermid;
+    else
+      pointermax = pointermid;
+    pointermid = Math.floor((pointermax - pointermin) / 2 + pointermin);
+  }
+  var commonprefix = text1.substring(0, pointermid);
+  text1 = text1.substring(pointermid);
+  text2 = text2.substring(pointermid);
+  return [text1, text2, commonprefix];
+}
+
+
+function diff_suffix(text1, text2) {
+  // Trim off common suffix
+  var pointermin = 0;
+  var pointermax = Math.min(text1.length, text2.length);
+  var pointermid = pointermax;
+  while(pointermin < pointermid) {
+    if (text1.substring(text1.length-pointermid) == text2.substring(text2.length-pointermid))
+      pointermin = pointermid;
+    else
+      pointermax = pointermid;
+    pointermid = Math.floor((pointermax - pointermin) / 2 + pointermin);
+  }
+  var commonsuffix = text1.substring(text1.length-pointermid);
+  text1 = text1.substring(0, text1.length-pointermid);
+  text2 = text2.substring(0, text2.length-pointermid);
+  return [text1, text2, commonsuffix];
+}
+
+
+function diff_halfmatch(text1, text2) {
+  // Do the two texts share a substring which is at least half the length of the longer text?
+  var longtext = text1.length > text2.length ? text1 : text2;
+  var shorttext = text1.length > text2.length ? text2 : text1;
+  if (longtext.length < 10 || shorttext.length < 1)
+    return null; // Pointless.
+
+  function diff_halfmatch_i(longtext, shorttext, i) {
+    // Start with a 1/4 length substring at position i as a seed.
+    var seed = longtext.substring(i, i+Math.floor(longtext.length/4));
+    var j = -1;
+    var best_common = '';
+    var best_longtext_a, best_longtext_b, best_shorttext_a, best_shorttext_b;
+    while ((j = shorttext.indexOf(seed, j+1)) != -1) {
+      var my_prefix = diff_prefix(longtext.substring(i), shorttext.substring(j));
+      var my_suffix = diff_suffix(longtext.substring(0, i), shorttext.substring(0, j));
+      if (best_common.length < (my_suffix[2] + my_prefix[2]).length) {
+        best_common = my_suffix[2] + my_prefix[2];
+        best_longtext_a = my_suffix[0];
+        best_longtext_b = my_prefix[0];
+        best_shorttext_a = my_suffix[1];
+        best_shorttext_b = my_prefix[1];
+      }
+    }
+    if (best_common.length >= longtext.length/2)
+      return [best_longtext_a, best_longtext_b, best_shorttext_a, best_shorttext_b, best_common];
+    else
+      return null;
+  }
+
+  // First check if the second quarter is the seed for a half-match.
+  var hm1 = diff_halfmatch_i(longtext, shorttext, Math.ceil(longtext.length/4));
+  // Check again based on the third quarter.
+  var hm2 = diff_halfmatch_i(longtext, shorttext, Math.ceil(longtext.length/2));
+  var hm;
+  if (!hm1 && !hm2)
+    return null;
+  else if (!hm2)
+    hm = hm1;
+  else if (!hm1)
+    hm = hm2;
+  else // Both matched.  Select the longest.
+    hm = hm1[4].length > hm2[4].length ? hm1 : hm2;
+
+  // A half-match was found, sort out the return data.
+  if (text1.length > text2.length) {
+    var text1_a = hm[0];
+    var text1_b = hm[1];
+    var text2_a = hm[2];
+    var text2_b = hm[3];
+  } else {
+    var text2_a = hm[0];
+    var text2_b = hm[1];
+    var text1_a = hm[2];
+    var text1_b = hm[3];
+  }
+  var mid_common = hm[4];
+  return [text1_a, text1_b, text2_a, text2_b, mid_common];
+}
+
+
+function diff_cleanup_semantic(diff) {
+  // Reduce the number of edits by eliminating semantically trivial equalities.
+  var changes = false;
+  var equalities = []; // Stack of indices where equalities are found.
+  var lastequality = null; // Always equal to equalities[equalities.length-1][1]
+  var pointer = 0; // Index of current position.
+  var length_changes1 = 0; // Number of characters that changed prior to the equality.
+  var length_changes2 = 0; // Number of characters that changed after the equality.
+  while (pointer < diff.length) {
+    if (diff[pointer][0] == 0) { // equality found
+      equalities.push(pointer);
+      length_changes1 = length_changes2;
+      length_changes2 = 0;
+      lastequality = diff[pointer][1];
+    } else { // an insertion or deletion
+      length_changes2 += diff[pointer][1].length;
+      if (lastequality != null && (lastequality.length <= length_changes1) && (lastequality.length <= length_changes2)) {
+        //alert("Splitting: '"+lastequality+"'");
+        diff.splice(equalities[equalities.length-1], 0, [-1, lastequality]); // Duplicate record
+        diff[equalities[equalities.length-1]+1][0] = 1; // Change second copy to insert.
+        equalities.pop();  // Throw away the equality we just deleted;
+        equalities.pop();  // Throw away the previous equality;
+        pointer = equalities.length ? equalities[equalities.length-1] : -1;
+        length_changes1 = 0; // Reset the counters.
+        length_changes2 = 0;
+        lastequality = null;
+        changes = true;
+      }
+    }
+    pointer++;
+  }
+
+  if (changes)
+    diff_cleanup_merge(diff);
+}
+
+
+function diff_cleanup_efficiency(diff) {
+  // Reduce the number of edits by eliminating operationally trivial equalities.
+  var changes = false;
+  var equalities = []; // Stack of indices where equalities are found.
+  var lastequality = ''; // Always equal to equalities[equalities.length-1][1]
+  var pointer = 0; // Index of current position.
+  var pre_ins = false; // Is there an insertion operation before the last equality.
+  var pre_del = false; // Is there an deletion operation before the last equality.
+  var post_ins = false; // Is there an insertion operation after the last equality.
+  var post_del = false; // Is there an deletion operation after the last equality.
+  while (pointer < diff.length) {
+    if (diff[pointer][0] == 0) { // equality found
+      if (diff[pointer][1].length < DIFF_EDIT_COST && (post_ins || post_del)) {
+        // Candidate found.
+        equalities.push(pointer);
+        pre_ins = post_ins;
+        pre_del = post_del;
+        lastequality = diff[pointer][1];
+      } else {
+        // Not a candidate, and can never become one.
+        equalities = [];
+        lastequality = '';
+      }
+      post_ins = post_del = false;
+    } else { // an insertion or deletion
+      if (diff[pointer][0] == -1)
+        post_del = true;
+      else
+        post_ins = true;
+      // Five types to be split:
+      // <ins>A</ins><del>B</del>XY<ins>C</ins><del>D</del>
+      // <ins>A</ins>X<ins>C</ins><del>D</del>
+      // <ins>A</ins><del>B</del>X<ins>C</ins>
+      // <ins>A</del>X<ins>C</ins><del>D</del>
+      // <ins>A</ins><del>B</del>X<del>C</del>
+      if (lastequality && ((pre_ins && pre_del && post_ins && post_del) || ((lastequality.length < DIFF_EDIT_COST/2) && (pre_ins + pre_del + post_ins + post_del) == 3))) {
+        //alert("Splitting: '"+lastequality+"'");
+        diff.splice(equalities[equalities.length-1], 0, [-1, lastequality]); // Duplicate record
+        diff[equalities[equalities.length-1]+1][0] = 1; // Change second copy to insert.
+        equalities.pop();  // Throw away the equality we just deleted;
+        lastequality = '';
+        if (pre_ins && pre_del) {
+          // No changes made which could affect previous entry, keep going.
+          post_ins = post_del = true;
+          equalities = [];
+        } else {
+          equalities.pop();  // Throw away the previous equality;
+          pointer = equalities.length ? equalities[equalities.length-1] : -1;
+          post_ins = post_del = false;
+        }
+        changes = true;
+      }
+    }
+    pointer++;
+  }
+
+  if (changes)
+    diff_cleanup_merge(diff);
+}
+
+
+function diff_cleanup_merge(diff) {
+  // Reorder and merge like edit sections.  Merge equalities.
+  // Any edit section can move as long as it doesn't cross an equality.
+  diff.push([0, '']);  // Add a dummy entry at the end.
+  var pointer = 0;
+  var count_delete = 0;
+  var count_insert = 0;
+  var text_delete = '';
+  var text_insert = '';
+  var record_insert, record_delete;
+  var my_xfix;
+  while(pointer < diff.length) {
+    if (diff[pointer][0] == 1) {
+      count_insert++;
+      text_insert += diff[pointer][1];
+      pointer++;
+    } else if (diff[pointer][0] == -1) {
+      count_delete++;
+      text_delete += diff[pointer][1];
+      pointer++;
+    } else {  // Upon reaching an equality, check for prior redundancies.
+      if (count_delete > 1 || count_insert > 1) {
+        if (count_delete > 1 && count_insert > 1) {
+          // Factor out any common prefixies.
+          my_xfix = diff_prefix(text_insert, text_delete);
+          if (my_xfix[2] != '') {
+            if ((pointer - count_delete - count_insert) > 0 && diff[pointer - count_delete - count_insert - 1][0] == 0) {
+              text_insert = my_xfix[0];
+              text_delete = my_xfix[1];
+              diff[pointer - count_delete - count_insert - 1][1] += my_xfix[2];
+            }
+          }
+          // Factor out any common suffixies.
+          my_xfix = diff_suffix(text_insert, text_delete);
+          if (my_xfix[2] != '') {
+            text_insert = my_xfix[0];
+            text_delete = my_xfix[1];
+            diff[pointer][1] = my_xfix[2] + diff[pointer][1];
+          }
+        }
+        // Delete the offending records and add the merged ones.
+        if (count_delete == 0)
+          diff.splice(pointer - count_delete - count_insert, count_delete + count_insert, [1, text_insert]);
+        else if (count_insert == 0)
+          diff.splice(pointer - count_delete - count_insert, count_delete + count_insert, [-1, text_delete]);
+        else
+          diff.splice(pointer - count_delete - count_insert, count_delete + count_insert, [-1, text_delete], [1, text_insert]);
+        pointer = pointer - count_delete - count_insert + (count_delete ? 1 : 0) + (count_insert ? 1 : 0) + 1;
+      } else if (pointer != 0 && diff[pointer-1][0] == 0) {
+        // Merge this equality with the previous one.
+        diff[pointer-1][1] += diff[pointer][1];
+        diff.splice(pointer, 1);
+      } else {
+        pointer++;
+      }
+      count_insert = 0;
+      count_delete = 0;
+      text_delete = '';
+      text_insert = '';
+    }
+  }
+  if (diff[diff.length-1][1] == '')
+    diff.pop();  // Remove the dummy entry at the end.
+}
+
+
+function diff_addindex(diff) {
+  // Add an index to each tuple, represents where the tuple is located in text2.
+  // e.g. [[-1, 'h', 0], [1, 'c', 0], [0, 'at', 1]]
+  var i = 0;
+  for (var x=0; x<diff.length; x++) {
+    diff[x].push(i);
+    if (diff[x][0] != -1)
+      i += diff[x][1].length;
+  }
+}
+
+
+function diff_xindex(diff, loc) {
+  // loc is a location in text1, compute and return the equivalent location in text2.
+  // e.g. "The cat" vs "The big cat", 1->1, 5->8
+  var chars1 = 0;
+  var chars2 = 0;
+  var last_chars1 = 0;
+  var last_chars2 = 0;
+  for (var x=0; x<diff.length; x++) {
+    if (diff[x][0] != 1) // Equality or deletion.
+      chars1 += diff[x][1].length;
+    if (diff[x][0] != -1) // Equality or insertion.
+      chars2 += diff[x][1].length;
+    if (chars1 > loc) // Overshot the location.
+      break;
+    last_chars1 = chars1;
+    last_chars2 = chars2;
+  }
+  if (diff.length != x && diff[x][0] == -1) // The location was deleted.
+    return last_chars2;
+  // Add the remaining character length.
+  return last_chars2 + (loc - last_chars1);
+}
+
+
+function diff_prettyhtml(diff) {
+  // Convert a diff array into a pretty HTML report.
+  diff_addindex(diff);
+  var html = '';
+  for (var x=0; x<diff.length; x++) {
+    var m = diff[x][0]; // Mode (-1=delete, 0=copy, 1=add)
+    var t = diff[x][1]; // Text of change.
+    var i = diff[x][2]; // Index of change.
+    t = t.replace(/&/g, "&amp;").replace(/</g, "&lt;").replace(/>/g, "&gt;");
+    t = t.replace(/\n/g, "&para;<BR>");
+    if (m == -1)
+      html += "<DEL STYLE='background:#FFE6E6;' TITLE='i="+i+"'>"+t+"</DEL>";
+    else if (m == 1)
+      html += "<INS STYLE='background:#E6FFE6;' TITLE='i="+i+"'>"+t+"</INS>";
+    else
+      html += "<SPAN TITLE='i="+i+"'>"+t+"</SPAN>";
+  }
+  return html;
+}
+
+
+  //////////////////////////////////////////////////////////////////////
+ //  Match                                                           //
+//////////////////////////////////////////////////////////////////////
+
+
+function match_getmaxbits() {
+  // Compute the number of bits in an int.
+  // The normal answer for JavaScript is 32.
+  var maxbits = 0;
+  var oldi = 1;
+  var newi = 2;
+  while (oldi != newi) {
+    maxbits++;
+    oldi = newi;
+    newi = newi << 1;
+  }
+  return maxbits;
+}
+var MATCH_MAXBITS = match_getmaxbits();
+
+
+function match_main(text, pattern, loc) {
+  // Locate the best instance of 'pattern' in 'text' near 'loc'.
+  loc = Math.max(0, Math.min(loc, text.length-pattern.length));
+  if (text == pattern) {
+    // Shortcut (potentially not guaranteed by the algorithm)
+    return 0;
+  } else if (text.length == 0) {
+    // Nothing to match.
+    return null;
+  } else if (text.substring(loc, loc + pattern.length) == pattern) {
+    // Perfect match at the perfect spot!  (Includes case of null pattern)
+    return loc;
+  } else {
+    // Do a fuzzy compare.
+    var match = match_bitap(text, pattern, loc);
+    return match;
+  }
+}
+
+
+function match_bitap(text, pattern, loc) {
+  // Locate the best instance of 'pattern' in 'text' near 'loc' using the Bitap algorithm.
+  if (pattern.length > MATCH_MAXBITS)
+    return alert("Pattern too long for this browser.");
+
+  // Initialise the alphabet.
+  var s = match_alphabet(pattern);
+
+  var score_text_length = text.length;
+  // Coerce the text length between reasonable maximums and minimums.
+  score_text_length = Math.max(score_text_length, MATCH_MINLENGTH);
+  score_text_length = Math.min(score_text_length, MATCH_MAXLENGTH);
+
+  function match_bitap_score (e, x) {
+    // Compute and return the score for a match with e errors and x location.
+    var d = Math.abs(loc-x);
+    return (e / pattern.length / MATCH_BALANCE) + (d / score_text_length / (1.0 - MATCH_BALANCE));
+  }
+
+  // Highest score beyond which we give up.
+  var score_threshold = MATCH_THRESHOLD;
+  // Is there a nearby exact match? (speedup)
+  var best_loc = text.indexOf(pattern, loc);
+  if (best_loc != -1)
+    score_threshold = Math.min(match_bitap_score(0, best_loc), score_threshold);
+  // What about in the other direction? (speedup)
+  best_loc = text.lastIndexOf(pattern, loc+pattern.length);
+  if (best_loc != -1)
+    score_threshold = Math.min(match_bitap_score(0, best_loc), score_threshold);
+
+  // Initialise the bit arrays.
+  var r = Array();
+  var d = -1;
+  var matchmask = Math.pow(2, pattern.length-1);
+  best_loc = null;
+
+  var bin_min, bin_mid;
+  var bin_max = Math.max(loc+loc, text.length);
+  var last_rd;
+  for (var d=0; d<pattern.length; d++) {
+    // Scan for the best match; each iteration allows for one more error.
+    var rd = Array(text.length);
+
+    // Run a binary search to determine how far from 'loc' we can stray at this error level.
+    bin_min = loc;
+    bin_mid = bin_max;
+    while(bin_min < bin_mid) {
+      if (match_bitap_score(d, bin_mid) < score_threshold)
+        bin_min = bin_mid;
+      else
+        bin_max = bin_mid;
+      bin_mid = Math.floor((bin_max - bin_min) / 2 + bin_min);
+    }
+    bin_max = bin_mid; // Use the result from this iteration as the maximum for the next.
+    var start = Math.max(0, loc - (bin_mid - loc) - 1);
+    var finish = Math.min(text.length-1, pattern.length + bin_mid);
+
+    if (text.charAt(finish) == pattern.charAt(pattern.length-1))
+      rd[finish] = Math.pow(2, d+1)-1;
+    else
+      rd[finish] = Math.pow(2, d)-1;
+    for (var j=finish-1; j>=start; j--) {
+      // The alphabet (s) is a sparse hash, so the following lines generate warnings.
+      if (d == 0) // First pass: exact match.
+        rd[j] = ((rd[j+1] << 1) | 1) & s[text.charAt(j)];
+      else // Subsequent passes: fuzzy match.
+        rd[j] = ((rd[j+1] << 1) | 1) & s[text.charAt(j)] | ((last_rd[j+1] << 1) | 1) | ((last_rd[j] << 1) | 1) | last_rd[j+1];
+      if (rd[j] & matchmask) {
+        var score = match_bitap_score(d, j);
+        // This match will almost certainly be better than any existing match.  But check anyway.
+        if (score <= score_threshold) {
+          // Told you so.
+          score_threshold = score;
+          best_loc = j;
+          if (j > loc) {
+            // When passing loc, don't exceed our current distance from loc.
+            start = Math.max(0, loc - (j - loc));
+          } else {
+            // Already passed loc, downhill from here on in.
+            break;
+          }
+        }
+      }
+    }
+    if (match_bitap_score(d+1, loc) > score_threshold) // No hope for a (better) match at greater error levels.
+      break;
+    last_rd = rd;
+  }
+  return best_loc;
+}
+
+
+function match_alphabet(pattern) {
+  // Initialise the alphabet for the Bitap algorithm.
+  var s = Object();
+  for (var i=0; i<pattern.length; i++)
+    s[pattern.charAt(i)] = 0;
+  for (var i=0; i<pattern.length; i++)
+    s[pattern.charAt(i)] |= Math.pow(2, pattern.length-i-1);
+  return s;
+}
+
+
+  //////////////////////////////////////////////////////////////////////
+ //  Patch                                                           //
+//////////////////////////////////////////////////////////////////////
+
+
+function patch_obj() {
+  // Constructor for a patch object.
+  this.diffs = [];
+  this.start1 = null;
+  this.start2 = null;
+  this.length1 = 0;
+  this.length2 = 0;
+
+  this.toString = function() {
+    // Emmulate GNU diff's format.
+    // Header: @@ -382,8 +481,9 @@
+    // Indicies are printed as 1-based, not 0-based.
+    var coords1, coords2;
+    if (this.length1 == 0)
+      coords1 = this.start1+",0";
+    else if (this.length1 == 1)
+      coords1 = this.start1+1;
+    else
+      coords1 = (this.start1+1)+","+this.length1;
+    if (this.length2 == 0)
+      coords2 = this.start2+",0";
+    else if (this.length2 == 1)
+      coords2 = this.start2+1;
+    else
+      coords2 = (this.start2+1)+","+this.length2;
+    var txt = "@@ -"+coords1+" +"+coords2+" @@\n";
+    // Escape the body of the patch with %xx notation.
+    for (var x=0; x<this.diffs.length; x++)
+      txt += ("- +".charAt(this.diffs[x][0]+1)) + encodeURI(this.diffs[x][1]) + "\n";
+    return txt.replace(/%20/g, ' ');
+  }
+
+  this.text1 = function() {
+    // Compute and return the source text (all equalities and deletions).
+    var txt = '';
+    for (var x=0; x<this.diffs.length; x++)
+      if (this.diffs[x][0] == 0 || this.diffs[x][0] == -1)
+        txt += this.diffs[x][1];
+    return txt;
+  }
+
+  this.text2 = function() {
+    // Compute and return the destination text (all equalities and insertions).
+    var txt = '';
+    for (var x=0; x<this.diffs.length; x++)
+      if (this.diffs[x][0] == 0 || this.diffs[x][0] == 1)
+        txt += this.diffs[x][1];
+    return txt;
+  }
+}
+
+
+function patch_addcontext(patch, text) {
+  var pattern = text.substring(patch.start2, patch.start2+patch.length1);
+  var padding = 0;
+  // Increase the context until we're unique (but don't let the pattern expand beyond MATCH_MAXBITS).
+  while (text.indexOf(pattern) != text.lastIndexOf(pattern) && pattern.length < MATCH_MAXBITS-PATCH_MARGIN-PATCH_MARGIN) {
+    padding += PATCH_MARGIN;
+    pattern = text.substring(patch.start2 - padding, patch.start2+patch.length1 + padding);
+  }
+  // Add one chunk for good luck.
+  padding += PATCH_MARGIN;
+  // Add the prefix.
+  var prefix = text.substring(patch.start2 - padding, patch.start2);
+  if (prefix != '')
+    patch.diffs.unshift([0, prefix]);
+  // Add the suffix
+  var suffix = text.substring(patch.start2+patch.length1, patch.start2+patch.length1 + padding);
+  if (suffix != '')
+    patch.diffs.push([0, suffix]);
+
+  // Roll back the start points.
+  patch.start1 -= prefix.length;
+  patch.start2 -= prefix.length;
+  // Extend the lengths.
+  patch.length1 += prefix.length + suffix.length;
+  patch.length2 += prefix.length + suffix.length;
+}
+
+
+function patch_make(text1, text2, diff) {
+  // Compute a list of patches to turn text1 into text2.
+  // Use diff if provided, otherwise compute it ourselves.
+  if (typeof diff == 'undefined') {
+    diff = diff_main(text1, text2, true);
+    if (diff.length > 2) {
+      diff_cleanup_semantic(diff);
+      diff_cleanup_efficiency(diff);
+    }
+  }
+  if (diff.length == 0)
+    return []; // Get rid of the null case.
+  var patches = [];
+  var patch = new patch_obj();
+  var char_count1 = 0; // Number of characters into the text1 string.
+  var char_count2 = 0; // Number of characters into the text2 string.
+  var last_type = null;
+  var prepatch_text = text1; // Recreate the patches to determine context info.
+  var postpatch_text = text1;
+  for (var x=0; x<diff.length; x++) {
+    var diff_type = diff[x][0];
+    var diff_text = diff[x][1];
+
+    if (patch.diffs.length == 0 && diff_type != 0) {
+      // A new patch starts here.
+      patch.start1 = char_count1;
+      patch.start2 = char_count2;
+    }
+
+    if (diff_type == 1) {
+      // Insertion
+      patch.diffs.push(diff[x]);
+      patch.length2 += diff_text.length;
+      postpatch_text = postpatch_text.substring(0, char_count2) + diff_text + postpatch_text.substring(char_count2);
+    } else if (diff_type == -1) {
+      // Deletion.
+      patch.length1 += diff_text.length;
+      patch.diffs.push(diff[x]);
+      postpatch_text = postpatch_text.substring(0, char_count2) + postpatch_text.substring(char_count2 + diff_text.length);
+    } else if (diff_type == 0 && diff_text.length <= 2*PATCH_MARGIN && patch.diffs.length != 0 && diff.length != x+1) {
+      // Small equality inside a patch.
+      patch.diffs.push(diff[x]);
+      patch.length1 += diff_text.length;
+      patch.length2 += diff_text.length;
+    }
+
+    last_type = diff_type;
+    if (diff_type == 0 && diff_text.length >= 2*PATCH_MARGIN) {
+      // Time for a new patch.
+      if (patch.diffs.length != 0) {
+        patch_addcontext(patch, prepatch_text);
+        patches.push(patch);
+        var patch = new patch_obj();
+        last_type = null;
+        prepatch_text = postpatch_text;
+      }
+    }
+
+    // Update the current character count.
+    if (diff_type != 1)
+      char_count1 += diff_text.length;
+    if (diff_type != -1)
+      char_count2 += diff_text.length;
+  }
+  // Pick up the leftover patch if not empty.
+  if (patch.diffs.length != 0) {
+    patch_addcontext(patch, prepatch_text);
+    patches.push(patch);
+  }
+
+  return patches;
+}
+
+
+function patch_apply(patches, text) {
+  // Merge a set of patches onto the text.
+  // Return a patched text, as well as a list of true/false values indicating which patches were applied.
+  patch_splitmax(patches);
+  var results = [];
+  var delta = 0;
+  var expected_loc, start_loc;
+  var text1, text2;
+  var diff, mod, index1, index2;
+  for (var x=0; x<patches.length; x++) {
+    expected_loc = patches[x].start2 + delta;
+    text1 = patches[x].text1();
+    start_loc = match_main(text, text1, expected_loc);
+    if (start_loc == null) {
+      // No match found.  :(
+      results.push(false);
+    } else {
+      // Found a match.  :)
+      results.push(true);
+      delta = start_loc - expected_loc;
+      text2 = text.substring(start_loc, start_loc + text1.length);
+      if (text1 == text2) {
+        // Perfect match, just shove the replacement text in.
+        text = text.substring(0, start_loc) + patches[x].text2() + text.substring(start_loc + text1.length);
+      } else {
+        // Imperfect match.  Run a diff to get a framework of equivalent indicies.
+        diff = diff_main(text1, text2, false);
+        index1 = 0;
+        for (var y=0; y<patches[x].diffs.length; y++) {
+          mod = patches[x].diffs[y];
+          if (mod[0] != 0)
+            index2 = diff_xindex(diff, index1);
+          if (mod[0] == 1) // Insertion
+            text = text.substring(0, start_loc + index2) + mod[1] + text.substring(start_loc + index2);
+          else if (mod[0] == -1) // Deletion
+            text = text.substring(0, start_loc + index2) + text.substring(start_loc + diff_xindex(diff, index1 + mod[1].length));
+          if (mod[0] != -1)
+            index1 += mod[1].length;
+        }
+      }
+    }
+  }
+  return [text, results];
+}
+
+
+function patch_splitmax(patches) {
+  // Look through the patches and break up any which are longer than the maximum limit of the match algorithm.
+  var bigpatch, patch, patch_size, start1, start2, diff_type, diff_text, precontext, postcontext, empty;
+  for (var x=0; x<patches.length; x++) {
+    if (patches[x].length1 > MATCH_MAXBITS) {
+      bigpatch = patches[x];
+      // Remove the big old patch.
+      patches.splice(x, 1);
+      patch_size = MATCH_MAXBITS;
+      start1 = bigpatch.start1;
+      start2 = bigpatch.start2;
+      precontext = '';
+      while (bigpatch.diffs.length != 0) {
+        // Create one of several smaller patches.
+        patch = new patch_obj();
+        empty = true;
+        patch.start1 = start1 - precontext.length;
+        patch.start2 = start2 - precontext.length;
+        if (precontext  != '') {
+          patch.length1 = patch.length2 = precontext.length;
+          patch.diffs.push([0, precontext]);
+        }
+        while (bigpatch.diffs.length != 0 && patch.length1 < patch_size - PATCH_MARGIN) {
+          diff_type = bigpatch.diffs[0][0];
+          diff_text = bigpatch.diffs[0][1];
+          if (diff_type == 1) {
+            // Insertions are harmless.
+            patch.length2 += diff_text.length;
+            start2 += diff_text.length;
+            patch.diffs.push(bigpatch.diffs.shift());
+            empty = false;
+          } else {
+            // Deletion or equality.  Only take as much as we can stomach.
+            diff_text = diff_text.substring(0, patch_size - patch.length1 - PATCH_MARGIN);
+            patch.length1 += diff_text.length;
+            start1 += diff_text.length;
+            if (diff_type == 0) {
+              patch.length2 += diff_text.length;
+              start2 += diff_text.length;
+            } else {
+              empty = false;
+            }
+            patch.diffs.push([diff_type, diff_text]);
+            if (diff_text == bigpatch.diffs[0][1])
+              bigpatch.diffs.shift();
+            else
+              bigpatch.diffs[0][1] = bigpatch.diffs[0][1].substring(diff_text.length);
+          }
+        }
+        // Compute the head context for the next patch.
+        precontext = patch.text2();
+        precontext = precontext.substring(precontext.length - PATCH_MARGIN);
+        // Append the end context for this patch.
+        postcontext = bigpatch.text1().substring(0, PATCH_MARGIN);
+        if (postcontext  != '') {
+          patch.length1 += postcontext.length;
+          patch.length2 += postcontext.length;
+          if (patch.diffs.length > 0 && patch.diffs[patch.diffs.length-1][0] == 0)
+            patch.diffs[patch.diffs.length-1][1] += postcontext;
+          else
+            patch.diffs.push([0, postcontext]);
+        }
+        if (!empty)
+          patches.splice(x++, 0, patch);
+      }
+    }
+  }
+}
+
+
+function patch_totext(patches) {
+  // Take a list of patches and return a textual representation.
+  var text = '';
+  for (var x=0; x<patches.length; x++)
+    text += patches[x];
+  return text;
+}
+
+
+function patch_fromtext(text) {
+  // Take a textual representation of patches and return a list of patch objects.
+  var patches = [];
+  text = text.split('\n');
+  var patch, m, chars1, chars2, sign, line;
+  while (text.length != 0) {
+    m = text[0].match(/^@@ -(\d+),?(\d*) \+(\d+),?(\d*) @@$/);
+    if (!m)
+      return alert("Invalid patch string:\n"+text[0]);
+    patch = new patch_obj();
+    patches.push(patch);
+    patch.start1 = parseInt(m[1]);
+    if (m[2] == '') {
+      patch.start1--;
+      patch.length1 = 1;
+    } else if (m[2] == '0') {
+      patch.length1 = 0;
+    } else {
+      patch.start1--;
+      patch.length1 = parseInt(m[2]);
+    }
+
+    patch.start2 = parseInt(m[3]);
+    if (m[4] == '') {
+      patch.start2--;
+      patch.length2 = 1;
+    } else if (m[4] == '0') {
+      patch.length2 = 0;
+    } else {
+      patch.start2--;
+      patch.length2 = parseInt(m[4]);
+    }
+    text.shift();
+
+    while (text.length != 0) {
+      sign = text[0].charAt(0);
+      line = decodeURIComponent(text[0].substring(1));
+      if (sign == '-') {
+        // Deletion.
+        patch.diffs.push([-1, line]);
+      } else if (sign == '+') {
+        // Insertion.
+        patch.diffs.push([1, line]);
+      } else if (sign == ' ') {
+        // Minor equality.
+        patch.diffs.push([0, line]);
+      } else if (sign == '@') {
+        // Start of next patch.
+        break;
+      } else if (sign == '') {
+        // Blank line?  Whatever.
+      } else {
+        // WTF?
+        return alert("Invalid patch mode: '"+sign+"'\n"+line);
+      }
+      text.shift();
+    }
+  }
+  return patches;
+}
+
+// EOF