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File: apps/codiad/lib/diff_match_patch.js
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/** * Diff Match and Patch * * Copyright 2006 Google Inc. * http://code.google.com/p/google-diff-match-patch/ * * Licensed under the Apache License, Version 2.0 (the "License"); * you may not use this file except in compliance with the License. * You may obtain a copy of the License at * * http://www.apache.org/licenses/LICENSE-2.0 * * Unless required by applicable law or agreed to in writing, software * distributed under the License is distributed on an "AS IS" BASIS, * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. * See the License for the specific language governing permissions and * limitations under the License. */ /** * @fileoverview Computes the difference between two texts to create a patch. * Applies the patch onto another text, allowing for errors. * @author fraser@google.com (Neil Fraser) */ /** * Class containing the diff, match and patch methods. * @constructor */ function diff_match_patch() { // Defaults. // Redefine these in your program to override the defaults. // Number of seconds to map a diff before giving up (0 for infinity). this.Diff_Timeout = 1.0; // Cost of an empty edit operation in terms of edit characters. this.Diff_EditCost = 4; // At what point is no match declared (0.0 = perfection, 1.0 = very loose). this.Match_Threshold = 0.5; // How far to search for a match (0 = exact location, 1000+ = broad match). // A match this many characters away from the expected location will add // 1.0 to the score (0.0 is a perfect match). this.Match_Distance = 1000; // When deleting a large block of text (over ~64 characters), how close do // the contents have to be to match the expected contents. (0.0 = perfection, // 1.0 = very loose). Note that Match_Threshold controls how closely the // end points of a delete need to match. this.Patch_DeleteThreshold = 0.5; // Chunk size for context length. this.Patch_Margin = 4; // The number of bits in an int. this.Match_MaxBits = 32; } // DIFF FUNCTIONS /** * The data structure representing a diff is an array of tuples: * [[DIFF_DELETE, 'Hello'], [DIFF_INSERT, 'Goodbye'], [DIFF_EQUAL, ' world.']] * which means: delete 'Hello', add 'Goodbye' and keep ' world.' */ var DIFF_DELETE = -1; var DIFF_INSERT = 1; var DIFF_EQUAL = 0; /** @typedef {{0: number, 1: string}} */ diff_match_patch.Diff; /** * Find the differences between two texts. Simplifies the problem by stripping * any common prefix or suffix off the texts before diffing. * @param {string} text1 Old string to be diffed. * @param {string} text2 New string to be diffed. * @param {boolean=} opt_checklines Optional speedup flag. If present and false, * then don't run a line-level diff first to identify the changed areas. * Defaults to true, which does a faster, slightly less optimal diff. * @param {number} opt_deadline Optional time when the diff should be complete * by. Used internally for recursive calls. Users should set DiffTimeout * instead. * @return {!Array.<!diff_match_patch.Diff>} Array of diff tuples. */ diff_match_patch.prototype.diff_main = function(text1, text2, opt_checklines, opt_deadline) { // Set a deadline by which time the diff must be complete. if (typeof opt_deadline == 'undefined') { if (this.Diff_Timeout <= 0) { opt_deadline = Number.MAX_VALUE; } else { opt_deadline = (new Date).getTime() + this.Diff_Timeout * 1000; } } var deadline = opt_deadline; // Check for null inputs. if (text1 == null || text2 == null) { throw new Error('Null input. (diff_main)'); } // Check for equality (speedup). if (text1 == text2) { if (text1) { return [[DIFF_EQUAL, text1]]; } return []; } if (typeof opt_checklines == 'undefined') { opt_checklines = true; } var checklines = opt_checklines; // Trim off common prefix (speedup). var commonlength = this.diff_commonPrefix(text1, text2); var commonprefix = text1.substring(0, commonlength); text1 = text1.substring(commonlength); text2 = text2.substring(commonlength); // Trim off common suffix (speedup). commonlength = this.diff_commonSuffix(text1, text2); var commonsuffix = text1.substring(text1.length - commonlength); text1 = text1.substring(0, text1.length - commonlength); text2 = text2.substring(0, text2.length - commonlength); // Compute the diff on the middle block. var diffs = this.diff_compute_(text1, text2, checklines, deadline); // Restore the prefix and suffix. if (commonprefix) { diffs.unshift([DIFF_EQUAL, commonprefix]); } if (commonsuffix) { diffs.push([DIFF_EQUAL, commonsuffix]); } this.diff_cleanupMerge(diffs); return diffs; }; /** * Find the differences between two texts. Assumes that the texts do not * have any common prefix or suffix. * @param {string} text1 Old string to be diffed. * @param {string} text2 New string to be diffed. * @param {boolean} checklines Speedup flag. If false, then don't run a * line-level diff first to identify the changed areas. * If true, then run a faster, slightly less optimal diff. * @param {number} deadline Time when the diff should be complete by. * @return {!Array.<!diff_match_patch.Diff>} Array of diff tuples. * @private */ diff_match_patch.prototype.diff_compute_ = function(text1, text2, checklines, deadline) { var diffs; if (!text1) { // Just add some text (speedup). return [[DIFF_INSERT, text2]]; } if (!text2) { // Just delete some text (speedup). return [[DIFF_DELETE, text1]]; } /** @type {?string} */ var longtext = text1.length > text2.length ? text1 : text2; /** @type {?string} */ var shorttext = text1.length > text2.length ? text2 : text1; var i = longtext.indexOf(shorttext); if (i != -1) { // Shorter text is inside the longer text (speedup). diffs = [[DIFF_INSERT, longtext.substring(0, i)], [DIFF_EQUAL, shorttext], [DIFF_INSERT, longtext.substring(i + shorttext.length)]]; // Swap insertions for deletions if diff is reversed. if (text1.length > text2.length) { diffs[0][0] = diffs[2][0] = DIFF_DELETE; } return diffs; } if (shorttext.length == 1) { // Single character string. // After the previous speedup, the character can't be an equality. return [[DIFF_DELETE, text1], [DIFF_INSERT, text2]]; } longtext = shorttext = null; // Garbage collect. // Check to see if the problem can be split in two. var hm = this.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 diffs_a = this.diff_main(text1_a, text2_a, checklines, deadline); var diffs_b = this.diff_main(text1_b, text2_b, checklines, deadline); // Merge the results. return diffs_a.concat([[DIFF_EQUAL, mid_common]], diffs_b); } if (checklines && text1.length > 100 && text2.length > 100) { return this.diff_lineMode_(text1, text2, deadline); } return this.diff_bisect_(text1, text2, deadline); }; /** * Do a quick line-level diff on both strings, then rediff the parts for * greater accuracy. * This speedup can produce non-minimal diffs. * @param {string} text1 Old string to be diffed. * @param {string} text2 New string to be diffed. * @param {number} deadline Time when the diff should be complete by. * @return {!Array.<!diff_match_patch.Diff>} Array of diff tuples. * @private */ diff_match_patch.prototype.diff_lineMode_ = function(text1, text2, deadline) { // Scan the text on a line-by-line basis first. var a = this.diff_linesToChars_(text1, text2); text1 = a.chars1; text2 = a.chars2; var linearray = a.lineArray; var diffs = this.diff_main(text1, text2, false, deadline); // Convert the diff back to original text. this.diff_charsToLines_(diffs, linearray); // Eliminate freak matches (e.g. blank lines) this.diff_cleanupSemantic(diffs); // Rediff any replacement blocks, this time character-by-character. // Add a dummy entry at the end. diffs.push([DIFF_EQUAL, '']); var pointer = 0; var count_delete = 0; var count_insert = 0; var text_delete = ''; var text_insert = ''; while (pointer < diffs.length) { switch (diffs[pointer][0]) { case DIFF_INSERT: count_insert++; text_insert += diffs[pointer][1]; break; case DIFF_DELETE: count_delete++; text_delete += diffs[pointer][1]; break; case DIFF_EQUAL: // Upon reaching an equality, check for prior redundancies. if (count_delete >= 1 && count_insert >= 1) { // Delete the offending records and add the merged ones. diffs.splice(pointer - count_delete - count_insert, count_delete + count_insert); pointer = pointer - count_delete - count_insert; var a = this.diff_main(text_delete, text_insert, false, deadline); for (var j = a.length - 1; j >= 0; j--) { diffs.splice(pointer, 0, a[j]); } pointer = pointer + a.length; } count_insert = 0; count_delete = 0; text_delete = ''; text_insert = ''; break; } pointer++; } diffs.pop(); // Remove the dummy entry at the end. return diffs; }; /** * Find the 'middle snake' of a diff, split the problem in two * and return the recursively constructed diff. * See Myers 1986 paper: An O(ND) Difference Algorithm and Its Variations. * @param {string} text1 Old string to be diffed. * @param {string} text2 New string to be diffed. * @param {number} deadline Time at which to bail if not yet complete. * @return {!Array.<!diff_match_patch.Diff>} Array of diff tuples. * @private */ diff_match_patch.prototype.diff_bisect_ = function(text1, text2, deadline) { // Cache the text lengths to prevent multiple calls. var text1_length = text1.length; var text2_length = text2.length; var max_d = Math.ceil((text1_length + text2_length) / 2); var v_offset = max_d; var v_length = 2 * max_d; var v1 = new Array(v_length); var v2 = new Array(v_length); // Setting all elements to -1 is faster in Chrome & Firefox than mixing // integers and undefined. for (var x = 0; x < v_length; x++) { v1[x] = -1; v2[x] = -1; } v1[v_offset + 1] = 0; v2[v_offset + 1] = 0; var delta = text1_length - text2_length; // If the total number of characters is odd, then the front path will collide // with the reverse path. var front = (delta % 2 != 0); // Offsets for start and end of k loop. // Prevents mapping of space beyond the grid. var k1start = 0; var k1end = 0; var k2start = 0; var k2end = 0; for (var d = 0; d < max_d; d++) { // Bail out if deadline is reached. if ((new Date()).getTime() > deadline) { break; } // Walk the front path one step. for (var k1 = -d + k1start; k1 <= d - k1end; k1 += 2) { var k1_offset = v_offset + k1; var x1; if (k1 == -d || (k1 != d && v1[k1_offset - 1] < v1[k1_offset + 1])) { x1 = v1[k1_offset + 1]; } else { x1 = v1[k1_offset - 1] + 1; } var y1 = x1 - k1; while (x1 < text1_length && y1 < text2_length && text1.charAt(x1) == text2.charAt(y1)) { x1++; y1++; } v1[k1_offset] = x1; if (x1 > text1_length) { // Ran off the right of the graph. k1end += 2; } else if (y1 > text2_length) { // Ran off the bottom of the graph. k1start += 2; } else if (front) { var k2_offset = v_offset + delta - k1; if (k2_offset >= 0 && k2_offset < v_length && v2[k2_offset] != -1) { // Mirror x2 onto top-left coordinate system. var x2 = text1_length - v2[k2_offset]; if (x1 >= x2) { // Overlap detected. return this.diff_bisectSplit_(text1, text2, x1, y1, deadline); } } } } // Walk the reverse path one step. for (var k2 = -d + k2start; k2 <= d - k2end; k2 += 2) { var k2_offset = v_offset + k2; var x2; if (k2 == -d || (k2 != d && v2[k2_offset - 1] < v2[k2_offset + 1])) { x2 = v2[k2_offset + 1]; } else { x2 = v2[k2_offset - 1] + 1; } var y2 = x2 - k2; while (x2 < text1_length && y2 < text2_length && text1.charAt(text1_length - x2 - 1) == text2.charAt(text2_length - y2 - 1)) { x2++; y2++; } v2[k2_offset] = x2; if (x2 > text1_length) { // Ran off the left of the graph. k2end += 2; } else if (y2 > text2_length) { // Ran off the top of the graph. k2start += 2; } else if (!front) { var k1_offset = v_offset + delta - k2; if (k1_offset >= 0 && k1_offset < v_length && v1[k1_offset] != -1) { var x1 = v1[k1_offset]; var y1 = v_offset + x1 - k1_offset; // Mirror x2 onto top-left coordinate system. x2 = text1_length - x2; if (x1 >= x2) { // Overlap detected. return this.diff_bisectSplit_(text1, text2, x1, y1, deadline); } } } } } // Diff took too long and hit the deadline or // number of diffs equals number of characters, no commonality at all. return [[DIFF_DELETE, text1], [DIFF_INSERT, text2]]; }; /** * Given the location of the 'middle snake', split the diff in two parts * and recurse. * @param {string} text1 Old string to be diffed. * @param {string} text2 New string to be diffed. * @param {number} x Index of split point in text1. * @param {number} y Index of split point in text2. * @param {number} deadline Time at which to bail if not yet complete. * @return {!Array.<!diff_match_patch.Diff>} Array of diff tuples. * @private */ diff_match_patch.prototype.diff_bisectSplit_ = function(text1, text2, x, y, deadline) { var text1a = text1.substring(0, x); var text2a = text2.substring(0, y); var text1b = text1.substring(x); var text2b = text2.substring(y); // Compute both diffs serially. var diffs = this.diff_main(text1a, text2a, false, deadline); var diffsb = this.diff_main(text1b, text2b, false, deadline); return diffs.concat(diffsb); }; /** * Split two texts into an array of strings. Reduce the texts to a string of * hashes where each Unicode character represents one line. * @param {string} text1 First string. * @param {string} text2 Second string. * @return {{chars1: string, chars2: string, lineArray: !Array.<string>}} * An object containing the encoded text1, the encoded text2 and * the array of unique strings. * The zeroth element of the array of unique strings is intentionally blank. * @private */ diff_match_patch.prototype.diff_linesToChars_ = function(text1, text2) { var lineArray = []; // e.g. lineArray[4] == 'Hello\n' var lineHash = {}; // e.g. lineHash['Hello\n'] == 4 // '\x00' is a valid character, but various debuggers don't like it. // So we'll insert a junk entry to avoid generating a null character. lineArray[0] = ''; /** * Split a text into an array of strings. Reduce the texts to a string of * hashes where each Unicode character represents one line. * Modifies linearray and linehash through being a closure. * @param {string} text String to encode. * @return {string} Encoded string. * @private */ function diff_linesToCharsMunge_(text) { var chars = ''; // Walk the text, pulling out a substring for each line. // text.split('\n') would would temporarily double our memory footprint. // Modifying text would create many large strings to garbage collect. var lineStart = 0; var lineEnd = -1; // Keeping our own length variable is faster than looking it up. var lineArrayLength = lineArray.length; while (lineEnd < text.length - 1) { lineEnd = text.indexOf('\n', lineStart); if (lineEnd == -1) { lineEnd = text.length - 1; } var line = text.substring(lineStart, lineEnd + 1); lineStart = lineEnd + 1; if (lineHash.hasOwnProperty ? lineHash.hasOwnProperty(line) : (lineHash[line] !== undefined)) { chars += String.fromCharCode(lineHash[line]); } else { chars += String.fromCharCode(lineArrayLength); lineHash[line] = lineArrayLength; lineArray[lineArrayLength++] = line; } } return chars; } var chars1 = diff_linesToCharsMunge_(text1); var chars2 = diff_linesToCharsMunge_(text2); return {chars1: chars1, chars2: chars2, lineArray: lineArray}; }; /** * Rehydrate the text in a diff from a string of line hashes to real lines of * text. * @param {!Array.<!diff_match_patch.Diff>} diffs Array of diff tuples. * @param {!Array.<string>} lineArray Array of unique strings. * @private */ diff_match_patch.prototype.diff_charsToLines_ = function(diffs, lineArray) { for (var x = 0; x < diffs.length; x++) { var chars = diffs[x][1]; var text = []; for (var y = 0; y < chars.length; y++) { text[y] = lineArray[chars.charCodeAt(y)]; } diffs[x][1] = text.join(''); } }; /** * Determine the common prefix of two strings. * @param {string} text1 First string. * @param {string} text2 Second string. * @return {number} The number of characters common to the start of each * string. */ diff_match_patch.prototype.diff_commonPrefix = function(text1, text2) { // Quick check for common null cases. if (!text1 || !text2 || text1.charAt(0) != text2.charAt(0)) { return 0; } // Binary search. // Performance analysis: http://neil.fraser.name/news/2007/10/09/ var pointermin = 0; var pointermax = Math.min(text1.length, text2.length); var pointermid = pointermax; var pointerstart = 0; while (pointermin < pointermid) { if (text1.substring(pointerstart, pointermid) == text2.substring(pointerstart, pointermid)) { pointermin = pointermid; pointerstart = pointermin; } else { pointermax = pointermid; } pointermid = Math.floor((pointermax - pointermin) / 2 + pointermin); } return pointermid; }; /** * Determine the common suffix of two strings. * @param {string} text1 First string. * @param {string} text2 Second string. * @return {number} The number of characters common to the end of each string. */ diff_match_patch.prototype.diff_commonSuffix = function(text1, text2) { // Quick check for common null cases. if (!text1 || !text2 || text1.charAt(text1.length - 1) != text2.charAt(text2.length - 1)) { return 0; } // Binary search. // Performance analysis: http://neil.fraser.name/news/2007/10/09/ var pointermin = 0; var pointermax = Math.min(text1.length, text2.length); var pointermid = pointermax; var pointerend = 0; while (pointermin < pointermid) { if (text1.substring(text1.length - pointermid, text1.length - pointerend) == text2.substring(text2.length - pointermid, text2.length - pointerend)) { pointermin = pointermid; pointerend = pointermin; } else { pointermax = pointermid; } pointermid = Math.floor((pointermax - pointermin) / 2 + pointermin); } return pointermid; }; /** * Determine if the suffix of one string is the prefix of another. * @param {string} text1 First string. * @param {string} text2 Second string. * @return {number} The number of characters common to the end of the first * string and the start of the second string. * @private */ diff_match_patch.prototype.diff_commonOverlap_ = function(text1, text2) { // Cache the text lengths to prevent multiple calls. var text1_length = text1.length; var text2_length = text2.length; // Eliminate the null case. if (text1_length == 0 || text2_length == 0) { return 0; } // Truncate the longer string. if (text1_length > text2_length) { text1 = text1.substring(text1_length - text2_length); } else if (text1_length < text2_length) { text2 = text2.substring(0, text1_length); } var text_length = Math.min(text1_length, text2_length); // Quick check for the worst case. if (text1 == text2) { return text_length; } // Start by looking for a single character match // and increase length until no match is found. // Performance analysis: http://neil.fraser.name/news/2010/11/04/ var best = 0; var length = 1; while (true) { var pattern = text1.substring(text_length - length); var found = text2.indexOf(pattern); if (found == -1) { return best; } length += found; if (found == 0 || text1.substring(text_length - length) == text2.substring(0, length)) { best = length; length++; } } }; /** * Do the two texts share a substring which is at least half the length of the * longer text? * This speedup can produce non-minimal diffs. * @param {string} text1 First string. * @param {string} text2 Second string. * @return {Array.<string>} Five element Array, containing the prefix of * text1, the suffix of text1, the prefix of text2, the suffix of * text2 and the common middle. Or null if there was no match. * @private */ diff_match_patch.prototype.diff_halfMatch_ = function(text1, text2) { if (this.Diff_Timeout <= 0) { // Don't risk returning a non-optimal diff if we have unlimited time. return null; } var longtext = text1.length > text2.length ? text1 : text2; var shorttext = text1.length > text2.length ? text2 : text1; if (longtext.length < 4 || shorttext.length * 2 < longtext.length) { return null; // Pointless. } var dmp = this; // 'this' becomes 'window' in a closure. /** * Does a substring of shorttext exist within longtext such that the substring * is at least half the length of longtext? * Closure, but does not reference any external variables. * @param {string} longtext Longer string. * @param {string} shorttext Shorter string. * @param {number} i Start index of quarter length substring within longtext. * @return {Array.<string>} Five element Array, containing the prefix of * longtext, the suffix of longtext, the prefix of shorttext, the suffix * of shorttext and the common middle. Or null if there was no match. * @private */ function diff_halfMatchI_(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 prefixLength = dmp.diff_commonPrefix(longtext.substring(i), shorttext.substring(j)); var suffixLength = dmp.diff_commonSuffix(longtext.substring(0, i), shorttext.substring(0, j)); if (best_common.length < suffixLength + prefixLength) { best_common = shorttext.substring(j - suffixLength, j) + shorttext.substring(j, j + prefixLength); best_longtext_a = longtext.substring(0, i - suffixLength); best_longtext_b = longtext.substring(i + prefixLength); best_shorttext_a = shorttext.substring(0, j - suffixLength); best_shorttext_b = shorttext.substring(j + prefixLength); } } if (best_common.length * 2 >= longtext.length) { 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_halfMatchI_(longtext, shorttext, Math.ceil(longtext.length / 4)); // Check again based on the third quarter. var hm2 = diff_halfMatchI_(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. var text1_a, text1_b, text2_a, text2_b; if (text1.length > text2.length) { text1_a = hm[0]; text1_b = hm[1]; text2_a = hm[2]; text2_b = hm[3]; } else { text2_a = hm[0]; text2_b = hm[1]; text1_a = hm[2]; text1_b = hm[3]; } var mid_common = hm[4]; return [text1_a, text1_b, text2_a, text2_b, mid_common]; }; /** * Reduce the number of edits by eliminating semantically trivial equalities. * @param {!Array.<!diff_match_patch.Diff>} diffs Array of diff tuples. */ diff_match_patch.prototype.diff_cleanupSemantic = function(diffs) { var changes = false; var equalities = []; // Stack of indices where equalities are found. var equalitiesLength = 0; // Keeping our own length var is faster in JS. /** @type {?string} */ var lastequality = null; // Always equal to diffs[equalities[equalitiesLength - 1]][1] var pointer = 0; // Index of current position. // Number of characters that changed prior to the equality. var length_insertions1 = 0; var length_deletions1 = 0; // Number of characters that changed after the equality. var length_insertions2 = 0; var length_deletions2 = 0; while (pointer < diffs.length) { if (diffs[pointer][0] == DIFF_EQUAL) { // Equality found. equalities[equalitiesLength++] = pointer; length_insertions1 = length_insertions2; length_deletions1 = length_deletions2; length_insertions2 = 0; length_deletions2 = 0; lastequality = diffs[pointer][1]; } else { // An insertion or deletion. if (diffs[pointer][0] == DIFF_INSERT) { length_insertions2 += diffs[pointer][1].length; } else { length_deletions2 += diffs[pointer][1].length; } // Eliminate an equality that is smaller or equal to the edits on both // sides of it. if (lastequality && (lastequality.length <= Math.max(length_insertions1, length_deletions1)) && (lastequality.length <= Math.max(length_insertions2, length_deletions2))) { // Duplicate record. diffs.splice(equalities[equalitiesLength - 1], 0, [DIFF_DELETE, lastequality]); // Change second copy to insert. diffs[equalities[equalitiesLength - 1] + 1][0] = DIFF_INSERT; // Throw away the equality we just deleted. equalitiesLength--; // Throw away the previous equality (it needs to be reevaluated). equalitiesLength--; pointer = equalitiesLength > 0 ? equalities[equalitiesLength - 1] : -1; length_insertions1 = 0; // Reset the counters. length_deletions1 = 0; length_insertions2 = 0; length_deletions2 = 0; lastequality = null; changes = true; } } pointer++; } // Normalize the diff. if (changes) { this.diff_cleanupMerge(diffs); } this.diff_cleanupSemanticLossless(diffs); // Find any overlaps between deletions and insertions. // e.g: <del>abcxxx</del><ins>xxxdef</ins> // -> <del>abc</del>xxx<ins>def</ins> // e.g: <del>xxxabc</del><ins>defxxx</ins> // -> <ins>def</ins>xxx<del>abc</del> // Only extract an overlap if it is as big as the edit ahead or behind it. pointer = 1; while (pointer < diffs.length) { if (diffs[pointer - 1][0] == DIFF_DELETE && diffs[pointer][0] == DIFF_INSERT) { var deletion = diffs[pointer - 1][1]; var insertion = diffs[pointer][1]; var overlap_length1 = this.diff_commonOverlap_(deletion, insertion); var overlap_length2 = this.diff_commonOverlap_(insertion, deletion); if (overlap_length1 >= overlap_length2) { if (overlap_length1 >= deletion.length / 2 || overlap_length1 >= insertion.length / 2) { // Overlap found. Insert an equality and trim the surrounding edits. diffs.splice(pointer, 0, [DIFF_EQUAL, insertion.substring(0, overlap_length1)]); diffs[pointer - 1][1] = deletion.substring(0, deletion.length - overlap_length1); diffs[pointer + 1][1] = insertion.substring(overlap_length1); pointer++; } } else { if (overlap_length2 >= deletion.length / 2 || overlap_length2 >= insertion.length / 2) { // Reverse overlap found. // Insert an equality and swap and trim the surrounding edits. diffs.splice(pointer, 0, [DIFF_EQUAL, deletion.substring(0, overlap_length2)]); diffs[pointer - 1][0] = DIFF_INSERT; diffs[pointer - 1][1] = insertion.substring(0, insertion.length - overlap_length2); diffs[pointer + 1][0] = DIFF_DELETE; diffs[pointer + 1][1] = deletion.substring(overlap_length2); pointer++; } } pointer++; } pointer++; } }; /** * Look for single edits surrounded on both sides by equalities * which can be shifted sideways to align the edit to a word boundary. * e.g: The c<ins>at c</ins>ame. -> The <ins>cat </ins>came. * @param {!Array.<!diff_match_patch.Diff>} diffs Array of diff tuples. */ diff_match_patch.prototype.diff_cleanupSemanticLossless = function(diffs) { /** * Given two strings, compute a score representing whether the internal * boundary falls on logical boundaries. * Scores range from 6 (best) to 0 (worst). * Closure, but does not reference any external variables. * @param {string} one First string. * @param {string} two Second string. * @return {number} The score. * @private */ function diff_cleanupSemanticScore_(one, two) { if (!one || !two) { // Edges are the best. return 6; } // Each port of this function behaves slightly differently due to // subtle differences in each language's definition of things like // 'whitespace'. Since this function's purpose is largely cosmetic, // the choice has been made to use each language's native features // rather than force total conformity. var char1 = one.charAt(one.length - 1); var char2 = two.charAt(0); var nonAlphaNumeric1 = char1.match(diff_match_patch.nonAlphaNumericRegex_); var nonAlphaNumeric2 = char2.match(diff_match_patch.nonAlphaNumericRegex_); var whitespace1 = nonAlphaNumeric1 && char1.match(diff_match_patch.whitespaceRegex_); var whitespace2 = nonAlphaNumeric2 && char2.match(diff_match_patch.whitespaceRegex_); var lineBreak1 = whitespace1 && char1.match(diff_match_patch.linebreakRegex_); var lineBreak2 = whitespace2 && char2.match(diff_match_patch.linebreakRegex_); var blankLine1 = lineBreak1 && one.match(diff_match_patch.blanklineEndRegex_); var blankLine2 = lineBreak2 && two.match(diff_match_patch.blanklineStartRegex_); if (blankLine1 || blankLine2) { // Five points for blank lines. return 5; } else if (lineBreak1 || lineBreak2) { // Four points for line breaks. return 4; } else if (nonAlphaNumeric1 && !whitespace1 && whitespace2) { // Three points for end of sentences. return 3; } else if (whitespace1 || whitespace2) { // Two points for whitespace. return 2; } else if (nonAlphaNumeric1 || nonAlphaNumeric2) { // One point for non-alphanumeric. return 1; } return 0; } var pointer = 1; // Intentionally ignore the first and last element (don't need checking). while (pointer < diffs.length - 1) { if (diffs[pointer - 1][0] == DIFF_EQUAL && diffs[pointer + 1][0] == DIFF_EQUAL) { // This is a single edit surrounded by equalities. var equality1 = diffs[pointer - 1][1]; var edit = diffs[pointer][1]; var equality2 = diffs[pointer + 1][1]; // First, shift the edit as far left as possible. var commonOffset = this.diff_commonSuffix(equality1, edit); if (commonOffset) { var commonString = edit.substring(edit.length - commonOffset); equality1 = equality1.substring(0, equality1.length - commonOffset); edit = commonString + edit.substring(0, edit.length - commonOffset); equality2 = commonString + equality2; } // Second, step character by character right, looking for the best fit. var bestEquality1 = equality1; var bestEdit = edit; var bestEquality2 = equality2; var bestScore = diff_cleanupSemanticScore_(equality1, edit) + diff_cleanupSemanticScore_(edit, equality2); while (edit.charAt(0) === equality2.charAt(0)) { equality1 += edit.charAt(0); edit = edit.substring(1) + equality2.charAt(0); equality2 = equality2.substring(1); var score = diff_cleanupSemanticScore_(equality1, edit) + diff_cleanupSemanticScore_(edit, equality2); // The >= encourages trailing rather than leading whitespace on edits. if (score >= bestScore) { bestScore = score; bestEquality1 = equality1; bestEdit = edit; bestEquality2 = equality2; } } if (diffs[pointer - 1][1] != bestEquality1) { // We have an improvement, save it back to the diff. if (bestEquality1) { diffs[pointer - 1][1] = bestEquality1; } else { diffs.splice(pointer - 1, 1); pointer--; } diffs[pointer][1] = bestEdit; if (bestEquality2) { diffs[pointer + 1][1] = bestEquality2; } else { diffs.splice(pointer + 1, 1); pointer--; } } } pointer++; } }; // Define some regex patterns for matching boundaries. 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/; /** * Reduce the number of edits by eliminating operationally trivial equalities. * @param {!Array.<!diff_match_patch.Diff>} diffs Array of diff tuples. */ diff_match_patch.prototype.diff_cleanupEfficiency = function(diffs) { var changes = false; var equalities = []; // Stack of indices where equalities are found. var equalitiesLength = 0; // Keeping our own length var is faster in JS. /** @type {?string} */ var lastequality = null; // Always equal to diffs[equalities[equalitiesLength - 1]][1] var pointer = 0; // Index of current position. // Is there an insertion operation before the last equality. var pre_ins = false; // Is there a deletion operation before the last equality. var pre_del = false; // Is there an insertion operation after the last equality. var post_ins = false; // Is there a deletion operation after the last equality. var post_del = false; while (pointer < diffs.length) { if (diffs[pointer][0] == DIFF_EQUAL) { // Equality found. if (diffs[pointer][1].length < this.Diff_EditCost && (post_ins || post_del)) { // Candidate found. equalities[equalitiesLength++] = pointer; pre_ins = post_ins; pre_del = post_del; lastequality = diffs[pointer][1]; } else { // Not a candidate, and can never become one. equalitiesLength = 0; lastequality = null; } post_ins = post_del = false; } else { // An insertion or deletion. if (diffs[pointer][0] == DIFF_DELETE) { 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 < this.Diff_EditCost / 2) && (pre_ins + pre_del + post_ins + post_del) == 3))) { // Duplicate record. diffs.splice(equalities[equalitiesLength - 1], 0, [DIFF_DELETE, lastequality]); // Change second copy to insert. diffs[equalities[equalitiesLength - 1] + 1][0] = DIFF_INSERT; equalitiesLength--; // Throw away the equality we just deleted; lastequality = null; if (pre_ins && pre_del) { // No changes made which could affect previous entry, keep going. post_ins = post_del = true; equalitiesLength = 0; } else { equalitiesLength--; // Throw away the previous equality. pointer = equalitiesLength > 0 ? equalities[equalitiesLength - 1] : -1; post_ins = post_del = false; } changes = true; } } pointer++; } if (changes) { this.diff_cleanupMerge(diffs); } }; /** * Reorder and merge like edit sections. Merge equalities. * Any edit section can move as long as it doesn't cross an equality. * @param {!Array.<!diff_match_patch.Diff>} diffs Array of diff tuples. */ diff_match_patch.prototype.diff_cleanupMerge = function(diffs) { diffs.push([DIFF_EQUAL, '']); // 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 commonlength; while (pointer < diffs.length) { switch (diffs[pointer][0]) { case DIFF_INSERT: count_insert++; text_insert += diffs[pointer][1]; pointer++; break; case DIFF_DELETE: count_delete++; text_delete += diffs[pointer][1]; pointer++; break; case DIFF_EQUAL: // Upon reaching an equality, check for prior redundancies. if (count_delete + count_insert > 1) { if (count_delete !== 0 && count_insert !== 0) { // Factor out any common prefixies. commonlength = this.diff_commonPrefix(text_insert, text_delete); if (commonlength !== 0) { if ((pointer - count_delete - count_insert) > 0 && diffs[pointer - count_delete - count_insert - 1][0] == DIFF_EQUAL) { diffs[pointer - count_delete - count_insert - 1][1] += text_insert.substring(0, commonlength); } else { diffs.splice(0, 0, [DIFF_EQUAL, text_insert.substring(0, commonlength)]); pointer++; } text_insert = text_insert.substring(commonlength); text_delete = text_delete.substring(commonlength); } // Factor out any common suffixies. commonlength = this.diff_commonSuffix(text_insert, text_delete); if (commonlength !== 0) { diffs[pointer][1] = text_insert.substring(text_insert.length - commonlength) + diffs[pointer][1]; text_insert = text_insert.substring(0, text_insert.length - commonlength); text_delete = text_delete.substring(0, text_delete.length - commonlength); } } // Delete the offending records and add the merged ones. if (count_delete === 0) { diffs.splice(pointer - count_insert, count_delete + count_insert, [DIFF_INSERT, text_insert]); } else if (count_insert === 0) { diffs.splice(pointer - count_delete, count_delete + count_insert, [DIFF_DELETE, text_delete]); } else { diffs.splice(pointer - count_delete - count_insert, count_delete + count_insert, [DIFF_DELETE, text_delete], [DIFF_INSERT, text_insert]); } pointer = pointer - count_delete - count_insert + (count_delete ? 1 : 0) + (count_insert ? 1 : 0) + 1; } else if (pointer !== 0 && diffs[pointer - 1][0] == DIFF_EQUAL) { // Merge this equality with the previous one. diffs[pointer - 1][1] += diffs[pointer][1]; diffs.splice(pointer, 1); } else { pointer++; } count_insert = 0; count_delete = 0; text_delete = ''; text_insert = ''; break; } } if (diffs[diffs.length - 1][1] === '') { diffs.pop(); // Remove the dummy entry at the end. } // Second pass: look for single edits surrounded on both sides by equalities // which can be shifted sideways to eliminate an equality. // e.g: A<ins>BA</ins>C -> <ins>AB</ins>AC var changes = false; pointer = 1; // Intentionally ignore the first and last element (don't need checking). while (pointer < diffs.length - 1) { if (diffs[pointer - 1][0] == DIFF_EQUAL && diffs[pointer + 1][0] == DIFF_EQUAL) { // This is a single edit surrounded by equalities. if (diffs[pointer][1].substring(diffs[pointer][1].length - diffs[pointer - 1][1].length) == diffs[pointer - 1][1]) { // Shift the edit over the previous equality. diffs[pointer][1] = diffs[pointer - 1][1] + diffs[pointer][1].substring(0, diffs[pointer][1].length - diffs[pointer - 1][1].length); diffs[pointer + 1][1] = diffs[pointer - 1][1] + diffs[pointer + 1][1]; diffs.splice(pointer - 1, 1); changes = true; } else if (diffs[pointer][1].substring(0, diffs[pointer + 1][1].length) == diffs[pointer + 1][1]) { // Shift the edit over the next equality. diffs[pointer - 1][1] += diffs[pointer + 1][1]; diffs[pointer][1] = diffs[pointer][1].substring(diffs[pointer + 1][1].length) + diffs[pointer + 1][1]; diffs.splice(pointer + 1, 1); changes = true; } } pointer++; } // If shifts were made, the diff needs reordering and another shift sweep. if (changes) { this.diff_cleanupMerge(diffs); } }; /** * 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 * @param {!Array.<!diff_match_patch.Diff>} diffs Array of diff tuples. * @param {number} loc Location within text1. * @return {number} Location within text2. */ diff_match_patch.prototype.diff_xIndex = function(diffs, loc) { var chars1 = 0; var chars2 = 0; var last_chars1 = 0; var last_chars2 = 0; var x; for (x = 0; x < diffs.length; x++) { if (diffs[x][0] !== DIFF_INSERT) { // Equality or deletion. chars1 += diffs[x][1].length; } if (diffs[x][0] !== DIFF_DELETE) { // Equality or insertion. chars2 += diffs[x][1].length; } if (chars1 > loc) { // Overshot the location. break; } last_chars1 = chars1; last_chars2 = chars2; } // Was the location was deleted? if (diffs.length != x && diffs[x][0] === DIFF_DELETE) { return last_chars2; } // Add the remaining character length. return last_chars2 + (loc - last_chars1); }; /** * Convert a diff array into a pretty HTML report. * @param {!Array.<!diff_match_patch.Diff>} diffs Array of diff tuples. * @return {string} HTML representation. */ diff_match_patch.prototype.diff_prettyHtml = function(diffs) { var html = []; var pattern_amp = /&/g; var pattern_lt = /</g; var pattern_gt = />/g; var pattern_para = /\n/g; for (var x = 0; x < diffs.length; x++) { var op = diffs[x][0]; // Operation (insert, delete, equal) var data = diffs[x][1]; // Text of change. var text = data.replace(pattern_amp, '&amp;').replace(pattern_lt, '&lt;') .replace(pattern_gt, '&gt;').replace(pattern_para, '&para;<br>'); switch (op) { case DIFF_INSERT: html[x] = '<ins style="background:#e6ffe6;">' + text + '</ins>'; break; case DIFF_DELETE: html[x] = '<del style="background:#ffe6e6;">' + text + '</del>'; break; case DIFF_EQUAL: html[x] = '<span>' + text + '</span>'; break; } } return html.join(''); }; /** * Compute and return the source text (all equalities and deletions). * @param {!Array.<!diff_match_patch.Diff>} diffs Array of diff tuples. * @return {string} Source text. */ diff_match_patch.prototype.diff_text1 = function(diffs) { var text = []; for (var x = 0; x < diffs.length; x++) { if (diffs[x][0] !== DIFF_INSERT) { text[x] = diffs[x][1]; } } return text.join(''); }; /** * Compute and return the destination text (all equalities and insertions). * @param {!Array.<!diff_match_patch.Diff>} diffs Array of diff tuples. * @return {string} Destination text. */ diff_match_patch.prototype.diff_text2 = function(diffs) { var text = []; for (var x = 0; x < diffs.length; x++) { if (diffs[x][0] !== DIFF_DELETE) { text[x] = diffs[x][1]; } } return text.join(''); }; /** * Compute the Levenshtein distance; the number of inserted, deleted or * substituted characters. * @param {!Array.<!diff_match_patch.Diff>} diffs Array of diff tuples. * @return {number} Number of changes. */ diff_match_patch.prototype.diff_levenshtein = function(diffs) { var levenshtein = 0; var insertions = 0; var deletions = 0; for (var x = 0; x < diffs.length; x++) { var op = diffs[x][0]; var data = diffs[x][1]; switch (op) { case DIFF_INSERT: insertions += data.length; break; case DIFF_DELETE: deletions += data.length; break; case DIFF_EQUAL: // A deletion and an insertion is one substitution. levenshtein += Math.max(insertions, deletions); insertions = 0; deletions = 0; break; } } levenshtein += Math.max(insertions, deletions); return levenshtein; }; /** * 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'. * Operations are tab-separated. Inserted text is escaped using %xx notation. * @param {!Array.<!diff_match_patch.Diff>} diffs Array of diff tuples. * @return {string} Delta text. */ diff_match_patch.prototype.diff_toDelta = function(diffs) { var text = []; for (var x = 0; x < diffs.length; x++) { switch (diffs[x][0]) { case DIFF_INSERT: text[x] = '+' + encodeURI(diffs[x][1]); break; case DIFF_DELETE: text[x] = '-' + diffs[x][1].length; break; case DIFF_EQUAL: text[x] = '=' + diffs[x][1].length; break; } } return text.join('\t').replace(/%20/g, ' '); }; /** * Given the original text1, and an encoded string which describes the * operations required to transform text1 into text2, compute the full diff. * @param {string} text1 Source string for the diff. * @param {string} delta Delta text. * @return {!Array.<!diff_match_patch.Diff>} Array of diff tuples. * @throws {!Error} If invalid input. */ diff_match_patch.prototype.diff_fromDelta = function(text1, delta) { var diffs = []; var diffsLength = 0; // Keeping our own length var is faster in JS. var pointer = 0; // Cursor in text1 var tokens = delta.split(/\t/g); for (var x = 0; x < tokens.length; x++) { // Each token begins with a one character parameter which specifies the // operation of this token (delete, insert, equality). var param = tokens[x].substring(1); switch (tokens[x].charAt(0)) { case '+': try { diffs[diffsLength++] = [DIFF_INSERT, decodeURI(param)]; } catch (ex) { // Malformed URI sequence. throw new Error('Illegal escape in diff_fromDelta: ' + param); } break; case '-': // Fall through. case '=': var n = parseInt(param, 10); if (isNaN(n) || n < 0) { throw new Error('Invalid number in diff_fromDelta: ' + param); } var text = text1.substring(pointer, pointer += n); if (tokens[x].charAt(0) == '=') { diffs[diffsLength++] = [DIFF_EQUAL, text]; } else { diffs[diffsLength++] = [DIFF_DELETE, text]; } break; default: // Blank tokens are ok (from a trailing \t). // Anything else is an error. if (tokens[x]) { throw new Error('Invalid diff operation in diff_fromDelta: ' + tokens[x]); } } } if (pointer != text1.length) { throw new Error('Delta length (' + pointer + ') does not equal source text length (' + text1.length + ').'); } return diffs; }; // MATCH FUNCTIONS /** * Locate the best instance of 'pattern' in 'text' near 'loc'. * @param {string} text The text to search. * @param {string} pattern The pattern to search for. * @param {number} loc The location to search around. * @return {number} Best match index or -1. */ diff_match_patch.prototype.match_main = function(text, pattern, loc) { // Check for null inputs. if (text == null || pattern == null || loc == null) { throw new Error('Null input. (match_main)'); } loc = Math.max(0, Math.min(loc, text.length)); if (text == pattern) { // Shortcut (potentially not guaranteed by the algorithm) return 0; } else if (!text.length) { // Nothing to match. return -1; } 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. return this.match_bitap_(text, pattern, loc); } }; /** * Locate the best instance of 'pattern' in 'text' near 'loc' using the * Bitap algorithm. * @param {string} text The text to search. * @param {string} pattern The pattern to search for. * @param {number} loc The location to search around. * @return {number} Best match index or -1. * @private */ diff_match_patch.prototype.match_bitap_ = function(text, pattern, loc) { if (pattern.length > this.Match_MaxBits) { throw new Error('Pattern too long for this browser.'); } // Initialise the alphabet. var s = this.match_alphabet_(pattern); var dmp = this; // 'this' becomes 'window' in a closure. /** * Compute and return the score for a match with e errors and x location. * Accesses loc and pattern through being a closure. * @param {number} e Number of errors in match. * @param {number} x Location of match. * @return {number} Overall score for match (0.0 = good, 1.0 = bad). * @private */ function match_bitapScore_(e, x) { var accuracy = e / pattern.length; var proximity = Math.abs(loc - x); if (!dmp.Match_Distance) { // Dodge divide by zero error. return proximity ? 1.0 : accuracy; } return accuracy + (proximity / dmp.Match_Distance); } // Highest score beyond which we give up. var score_threshold = this.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_bitapScore_(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_bitapScore_(0, best_loc), score_threshold); } } // Initialise the bit arrays. var matchmask = 1 << (pattern.length - 1); best_loc = -1; var bin_min, bin_mid; var bin_max = pattern.length + 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. // Run a binary search to determine how far from 'loc' we can stray at this // error level. bin_min = 0; bin_mid = bin_max; while (bin_min < bin_mid) { if (match_bitapScore_(d, loc + bin_mid) <= score_threshold) { bin_min = bin_mid; } else { bin_max = bin_mid; } bin_mid = Math.floor((bin_max - bin_min) / 2 + bin_min); } // Use the result from this iteration as the maximum for the next. bin_max = bin_mid; var start = Math.max(1, loc - bin_mid + 1); var finish = Math.min(loc + bin_mid, text.length) + pattern.length; var rd = Array(finish + 2); rd[finish + 1] = (1 << d) - 1; for (var j = finish; j >= start; j--) { // The alphabet (s) is a sparse hash, so the following line generates // warnings. var charMatch = s[text.charAt(j - 1)]; if (d === 0) { // First pass: exact match. rd[j] = ((rd[j + 1] << 1) | 1) & charMatch; } else { // Subsequent passes: fuzzy match. rd[j] = (((rd[j + 1] << 1) | 1) & charMatch) | (((last_rd[j + 1] | last_rd[j]) << 1) | 1) | last_rd[j + 1]; } if (rd[j] & matchmask) { var score = match_bitapScore_(d, j - 1); // 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 - 1; if (best_loc > loc) { // When passing loc, don't exceed our current distance from loc. start = Math.max(1, 2 * loc - best_loc); } else { // Already passed loc, downhill from here on in. break; } } } } // No hope for a (better) match at greater error levels. if (match_bitapScore_(d + 1, loc) > score_threshold) { break; } last_rd = rd; } return best_loc; }; /** * Initialise the alphabet for the Bitap algorithm. * @param {string} pattern The text to encode. * @return {!Object} Hash of character locations. * @private */ diff_match_patch.prototype.match_alphabet_ = function(pattern) { var s = {}; 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)] |= 1 << (pattern.length - i - 1); } return s; }; // PATCH FUNCTIONS /** * Increase the context until it is unique, * but don't let the pattern expand beyond Match_MaxBits. * @param {!diff_match_patch.patch_obj} patch The patch to grow. * @param {string} text Source text. * @private */ diff_match_patch.prototype.patch_addContext_ = function(patch, text) { if (text.length == 0) { return; } var pattern = text.substring(patch.start2, patch.start2 + patch.length1); var padding = 0; // Look for the first and last matches of pattern in text. If two different // matches are found, increase the pattern length. while (text.indexOf(pattern) != text.lastIndexOf(pattern) && pattern.length < this.Match_MaxBits - this.Patch_Margin - this.Patch_Margin) { padding += this.Patch_Margin; pattern = text.substring(patch.start2 - padding, patch.start2 + patch.length1 + padding); } // Add one chunk for good luck. padding += this.Patch_Margin; // Add the prefix. var prefix = text.substring(patch.start2 - padding, patch.start2); if (prefix) { patch.diffs.unshift([DIFF_EQUAL, prefix]); } // Add the suffix. var suffix = text.substring(patch.start2 + patch.length1, patch.start2 + patch.length1 + padding); if (suffix) { patch.diffs.push([DIFF_EQUAL, 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; }; /** * Compute a list of patches to turn text1 into text2. * Use diffs if provided, otherwise compute it ourselves. * There are four ways to call this function, depending on what data is * available to the caller: * Method 1: * a = text1, b = text2 * Method 2: * a = diffs * Method 3 (optimal): * a = text1, b = diffs * Method 4 (deprecated, use method 3): * a = text1, b = text2, c = diffs * * @param {string|!Array.<!diff_match_patch.Diff>} a text1 (methods 1,3,4) or * Array of diff tuples for text1 to text2 (method 2). * @param {string|!Array.<!diff_match_patch.Diff>} opt_b text2 (methods 1,4) or * Array of diff tuples for text1 to text2 (method 3) or undefined (method 2). * @param {string|!Array.<!diff_match_patch.Diff>} opt_c Array of diff tuples * for text1 to text2 (method 4) or undefined (methods 1,2,3). * @return {!Array.<!diff_match_patch.patch_obj>} Array of Patch objects. */ diff_match_patch.prototype.patch_make = function(a, opt_b, opt_c) { var text1, diffs; if (typeof a == 'string' && typeof opt_b == 'string' && typeof opt_c == 'undefined') { // Method 1: text1, text2 // Compute diffs from text1 and text2. text1 = /** @type {string} */(a); diffs = this.diff_main(text1, /** @type {string} */(opt_b), true); if (diffs.length > 2) { this.diff_cleanupSemantic(diffs); this.diff_cleanupEfficiency(diffs); } } else if (a && typeof a == 'object' && typeof opt_b == 'undefined' && typeof opt_c == 'undefined') { // Method 2: diffs // Compute text1 from diffs. diffs = /** @type {!Array.<!diff_match_patch.Diff>} */(a); text1 = this.diff_text1(diffs); } else if (typeof a == 'string' && opt_b && typeof opt_b == 'object' && typeof opt_c == 'undefined') { // Method 3: text1, diffs text1 = /** @type {string} */(a); diffs = /** @type {!Array.<!diff_match_patch.Diff>} */(opt_b); } else if (typeof a == 'string' && typeof opt_b == 'string' && opt_c && typeof opt_c == 'object') { // Method 4: text1, text2, diffs // text2 is not used. text1 = /** @type {string} */(a); diffs = /** @type {!Array.<!diff_match_patch.Diff>} */(opt_c); } else { throw new Error('Unknown call format to patch_make.'); } if (diffs.length === 0) { return []; // Get rid of the null case. } var patches = []; var patch = new diff_match_patch.patch_obj(); var patchDiffLength = 0; // Keeping our own length var is faster in JS. var char_count1 = 0; // Number of characters into the text1 string. var char_count2 = 0; // Number of characters into the text2 string. // Start with text1 (prepatch_text) and apply the diffs until we arrive at // text2 (postpatch_text). We recreate the patches one by one to determine // context info. var prepatch_text = text1; var postpatch_text = text1; for (var x = 0; x < diffs.length; x++) { var diff_type = diffs[x][0]; var diff_text = diffs[x][1]; if (!patchDiffLength && diff_type !== DIFF_EQUAL) { // A new patch starts here. patch.start1 = char_count1; patch.start2 = char_count2; } switch (diff_type) { case DIFF_INSERT: patch.diffs[patchDiffLength++] = diffs[x]; patch.length2 += diff_text.length; postpatch_text = postpatch_text.substring(0, char_count2) + diff_text + postpatch_text.substring(char_count2); break; case DIFF_DELETE: patch.length1 += diff_text.length; patch.diffs[patchDiffLength++] = diffs[x]; postpatch_text = postpatch_text.substring(0, char_count2) + postpatch_text.substring(char_count2 + diff_text.length); break; case DIFF_EQUAL: if (diff_text.length <= 2 * this.Patch_Margin && patchDiffLength && diffs.length != x + 1) { // Small equality inside a patch. patch.diffs[patchDiffLength++] = diffs[x]; patch.length1 += diff_text.length; patch.length2 += diff_text.length; } else if (diff_text.length >= 2 * this.Patch_Margin) { // Time for a new patch. if (patchDiffLength) { this.patch_addContext_(patch, prepatch_text); patches.push(patch); patch = new diff_match_patch.patch_obj(); patchDiffLength = 0; // Unlike Unidiff, our patch lists have a rolling context. // http://code.google.com/p/google-diff-match-patch/wiki/Unidiff // Update prepatch text & pos to reflect the application of the // just completed patch. prepatch_text = postpatch_text; char_count1 = char_count2; } } break; } // Update the current character count. if (diff_type !== DIFF_INSERT) { char_count1 += diff_text.length; } if (diff_type !== DIFF_DELETE) { char_count2 += diff_text.length; } } // Pick up the leftover patch if not empty. if (patchDiffLength) { this.patch_addContext_(patch, prepatch_text); patches.push(patch); } return patches; }; /** * Given an array of patches, return another array that is identical. * @param {!Array.<!diff_match_patch.patch_obj>} patches Array of Patch objects. * @return {!Array.<!diff_match_patch.patch_obj>} Array of Patch objects. */ diff_match_patch.prototype.patch_deepCopy = function(patches) { // Making deep copies is hard in JavaScript. var patchesCopy = []; for (var x = 0; x < patches.length; x++) { var patch = patches[x]; var patchCopy = new diff_match_patch.patch_obj(); patchCopy.diffs = []; for (var y = 0; y < patch.diffs.length; y++) { patchCopy.diffs[y] = patch.diffs[y].slice(); } patchCopy.start1 = patch.start1; patchCopy.start2 = patch.start2; patchCopy.length1 = patch.length1; patchCopy.length2 = patch.length2; patchesCopy[x] = patchCopy; } return patchesCopy; }; /** * 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. * @param {!Array.<!diff_match_patch.patch_obj>} patches Array of Patch objects. * @param {string} text Old text. * @return {!Array.<string|!Array.<boolean>>} Two element Array, containing the * new text and an array of boolean values. */ diff_match_patch.prototype.patch_apply = function(patches, text) { if (patches.length == 0) { return [text, []]; } // Deep copy the patches so that no changes are made to originals. patches = this.patch_deepCopy(patches); var nullPadding = this.patch_addPadding(patches); text = nullPadding + text + nullPadding; this.patch_splitMax(patches); // delta keeps track of the offset between the expected and actual location // of the previous patch. If there are patches expected at positions 10 and // 20, but the first patch was found at 12, delta is 2 and the second patch // has an effective expected position of 22. var delta = 0; var results = []; for (var x = 0; x < patches.length; x++) { var expected_loc = patches[x].start2 + delta; var text1 = this.diff_text1(patches[x].diffs); var start_loc; var end_loc = -1; if (text1.length > this.Match_MaxBits) { // patch_splitMax will only provide an oversized pattern in the case of // a monster delete. start_loc = this.match_main(text, text1.substring(0, this.Match_MaxBits), expected_loc); if (start_loc != -1) { end_loc = this.match_main(text, text1.substring(text1.length - this.Match_MaxBits), expected_loc + text1.length - this.Match_MaxBits); if (end_loc == -1 || start_loc >= end_loc) { // Can't find valid trailing context. Drop this patch. start_loc = -1; } } } else { start_loc = this.match_main(text, text1, expected_loc); } if (start_loc == -1) { // No match found. :( results[x] = false; // Subtract the delta for this failed patch from subsequent patches. delta -= patches[x].length2 - patches[x].length1; } else { // Found a match. :) results[x] = true; delta = start_loc - expected_loc; var text2; if (end_loc == -1) { text2 = text.substring(start_loc, start_loc + text1.length); } else { text2 = text.substring(start_loc, end_loc + this.Match_MaxBits); } if (text1 == text2) { // Perfect match, just shove the replacement text in. text = text.substring(0, start_loc) + this.diff_text2(patches[x].diffs) + text.substring(start_loc + text1.length); } else { // Imperfect match. Run a diff to get a framework of equivalent // indices. var diffs = this.diff_main(text1, text2, false); if (text1.length > this.Match_MaxBits && this.diff_levenshtein(diffs) / text1.length > this.Patch_DeleteThreshold) { // The end points match, but the content is unacceptably bad. results[x] = false; } else { this.diff_cleanupSemanticLossless(diffs); var index1 = 0; var index2; for (var y = 0; y < patches[x].diffs.length; y++) { var mod = patches[x].diffs[y]; if (mod[0] !== DIFF_EQUAL) { index2 = this.diff_xIndex(diffs, index1); } if (mod[0] === DIFF_INSERT) { // Insertion text = text.substring(0, start_loc + index2) + mod[1] + text.substring(start_loc + index2); } else if (mod[0] === DIFF_DELETE) { // Deletion text = text.substring(0, start_loc + index2) + text.substring(start_loc + this.diff_xIndex(diffs, index1 + mod[1].length)); } if (mod[0] !== DIFF_DELETE) { index1 += mod[1].length; } } } } } } // Strip the padding off. text = text.substring(nullPadding.length, text.length - nullPadding.length); return [text, results]; }; /** * Add some padding on text start and end so that edges can match something. * Intended to be called only from within patch_apply. * @param {!Array.<!diff_match_patch.patch_obj>} patches Array of Patch objects. * @return {string} The padding string added to each side. */ diff_match_patch.prototype.patch_addPadding = function(patches) { var paddingLength = this.Patch_Margin; var nullPadding = ''; for (var x = 1; x <= paddingLength; x++) { nullPadding += String.fromCharCode(x); } // Bump all the patches forward. for (var x = 0; x < patches.length; x++) { patches[x].start1 += paddingLength; patches[x].start2 += paddingLength; } // Add some padding on start of first diff. var patch = patches[0]; var diffs = patch.diffs; if (diffs.length == 0 || diffs[0][0] != DIFF_EQUAL) { // Add nullPadding equality. diffs.unshift([DIFF_EQUAL, nullPadding]); patch.start1 -= paddingLength; // Should be 0. patch.start2 -= paddingLength; // Should be 0. patch.length1 += paddingLength; patch.length2 += paddingLength; } else if (paddingLength > diffs[0][1].length) { // Grow first equality. var extraLength = paddingLength - diffs[0][1].length; diffs[0][1] = nullPadding.substring(diffs[0][1].length) + diffs[0][1]; patch.start1 -= extraLength; patch.start2 -= extraLength; patch.length1 += extraLength; patch.length2 += extraLength; } // Add some padding on end of last diff. patch = patches[patches.length - 1]; diffs = patch.diffs; if (diffs.length == 0 || diffs[diffs.length - 1][0] != DIFF_EQUAL) { // Add nullPadding equality. diffs.push([DIFF_EQUAL, nullPadding]); patch.length1 += paddingLength; patch.length2 += paddingLength; } else if (paddingLength > diffs[diffs.length - 1][1].length) { // Grow last equality. var extraLength = paddingLength - diffs[diffs.length - 1][1].length; diffs[diffs.length - 1][1] += nullPadding.substring(0, extraLength); patch.length1 += extraLength; patch.length2 += extraLength; } return nullPadding; }; /** * Look through the patches and break up any which are longer than the maximum * limit of the match algorithm. * Intended to be called only from within patch_apply. * @param {!Array.<!diff_match_patch.patch_obj>} patches Array of Patch objects. */ diff_match_patch.prototype.patch_splitMax = function(patches) { var patch_size = this.Match_MaxBits; for (var x = 0; x < patches.length; x++) { if (patches[x].length1 <= patch_size) { continue; } var bigpatch = patches[x]; // Remove the big old patch. patches.splice(x--, 1); var start1 = bigpatch.start1; var start2 = bigpatch.start2; var precontext = ''; while (bigpatch.diffs.length !== 0) { // Create one of several smaller patches. var patch = new diff_match_patch.patch_obj(); var empty = true; patch.start1 = start1 - precontext.length; patch.start2 = start2 - precontext.length; if (precontext !== '') { patch.length1 = patch.length2 = precontext.length; patch.diffs.push([DIFF_EQUAL, precontext]); } while (bigpatch.diffs.length !== 0 && patch.length1 < patch_size - this.Patch_Margin) { var diff_type = bigpatch.diffs[0][0]; var diff_text = bigpatch.diffs[0][1]; if (diff_type === DIFF_INSERT) { // Insertions are harmless. patch.length2 += diff_text.length; start2 += diff_text.length; patch.diffs.push(bigpatch.diffs.shift()); empty = false; } else if (diff_type === DIFF_DELETE && patch.diffs.length == 1 && patch.diffs[0][0] == DIFF_EQUAL && diff_text.length > 2 * patch_size) { // This is a large deletion. Let it pass in one chunk. patch.length1 += diff_text.length; start1 += diff_text.length; empty = false; patch.diffs.push([diff_type, diff_text]); bigpatch.diffs.shift(); } else { // Deletion or equality. Only take as much as we can stomach. diff_text = diff_text.substring(0, patch_size - patch.length1 - this.Patch_Margin); patch.length1 += diff_text.length; start1 += diff_text.length; if (diff_type === DIFF_EQUAL) { 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 = this.diff_text2(patch.diffs); precontext = precontext.substring(precontext.length - this.Patch_Margin); // Append the end context for this patch. var postcontext = this.diff_text1(bigpatch.diffs) .substring(0, this.Patch_Margin); if (postcontext !== '') { patch.length1 += postcontext.length; patch.length2 += postcontext.length; if (patch.diffs.length !== 0 && patch.diffs[patch.diffs.length - 1][0] === DIFF_EQUAL) { patch.diffs[patch.diffs.length - 1][1] += postcontext; } else { patch.diffs.push([DIFF_EQUAL, postcontext]); } } if (!empty) { patches.splice(++x, 0, patch); } } } }; /** * Take a list of patches and return a textual representation. * @param {!Array.<!diff_match_patch.patch_obj>} patches Array of Patch objects. * @return {string} Text representation of patches. */ diff_match_patch.prototype.patch_toText = function(patches) { var text = []; for (var x = 0; x < patches.length; x++) { text[x] = patches[x]; } return text.join(''); }; /** * Parse a textual representation of patches and return a list of Patch objects. * @param {string} textline Text representation of patches. * @return {!Array.<!diff_match_patch.patch_obj>} Array of Patch objects. * @throws {!Error} If invalid input. */ diff_match_patch.prototype.patch_fromText = function(textline) { var patches = []; if (!textline) { return patches; } var text = textline.split('\n'); var textPointer = 0; var patchHeader = /^@@ -(\d+),?(\d*) \+(\d+),?(\d*) @@$/; while (textPointer < text.length) { var m = text[textPointer].match(patchHeader); if (!m) { throw new Error('Invalid patch string: ' + text[textPointer]); } var patch = new diff_match_patch.patch_obj(); patches.push(patch); patch.start1 = parseInt(m[1], 10); if (m[2] === '') { patch.start1--; patch.length1 = 1; } else if (m[2] == '0') { patch.length1 = 0; } else { patch.start1--; patch.length1 = parseInt(m[2], 10); } patch.start2 = parseInt(m[3], 10); if (m[4] === '') { patch.start2--; patch.length2 = 1; } else if (m[4] == '0') { patch.length2 = 0; } else { patch.start2--; patch.length2 = parseInt(m[4], 10); } textPointer++; while (textPointer < text.length) { var sign = text[textPointer].charAt(0); try { var line = decodeURI(text[textPointer].substring(1)); } catch (ex) { // Malformed URI sequence. throw new Error('Illegal escape in patch_fromText: ' + line); } if (sign == '-') { // Deletion. patch.diffs.push([DIFF_DELETE, line]); } else if (sign == '+') { // Insertion. patch.diffs.push([DIFF_INSERT, line]); } else if (sign == ' ') { // Minor equality. patch.diffs.push([DIFF_EQUAL, line]); } else if (sign == '@') { // Start of next patch. break; } else if (sign === '') { // Blank line? Whatever. } else { // WTF? throw new Error('Invalid patch mode "' + sign + '" in: ' + line); } textPointer++; } } return patches; }; /** * Class representing one patch operation. * @constructor */ diff_match_patch.patch_obj = function() { /** @type {!Array.<!diff_match_patch.Diff>} */ this.diffs = []; /** @type {?number} */ this.start1 = null; /** @type {?number} */ this.start2 = null; /** @type {number} */ this.length1 = 0; /** @type {number} */ this.length2 = 0; }; /** * Emmulate GNU diff's format. * Header: @@ -382,8 +481,9 @@ * Indicies are printed as 1-based, not 0-based. * @return {string} The GNU diff string. */ diff_match_patch.patch_obj.prototype.toString = function() { 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 text = ['@@ -' + coords1 + ' +' + coords2 + ' @@\n']; var op; // Escape the body of the patch with %xx notation. for (var x = 0; x < this.diffs.length; x++) { switch (this.diffs[x][0]) { case DIFF_INSERT: op = '+'; break; case DIFF_DELETE: op = '-'; break; case DIFF_EQUAL: op = ' '; break; } text[x + 1] = op + encodeURI(this.diffs[x][1]) + '\n'; } return text.join('').replace(/%20/g, ' '); }; // Export these global variables so that they survive Google's JS compiler. // In a browser, 'this' will be 'window'. // Users of node.js should 'require' the uncompressed version since Google's // JS compiler may break the following exports for non-browser environments. this['diff_match_patch'] = diff_match_patch; this['DIFF_DELETE'] = DIFF_DELETE; this['DIFF_INSERT'] = DIFF_INSERT; this['DIFF_EQUAL'] = DIFF_EQUAL;