1378 lines
47 KiB
JavaScript
1378 lines
47 KiB
JavaScript
/**
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* Diff Match and Patch
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*
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* Copyright 2006 Google Inc.
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* http://code.google.com/p/google-diff-match-patch/
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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/**
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* @fileoverview Computes the difference between two texts to create a patch.
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* Applies the patch onto another text, allowing for errors.
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* @author fraser@google.com (Neil Fraser)
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*/
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/**
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* Class containing the diff, match and patch methods.
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* @constructor
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*/
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function diff_match_patch() {
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// Defaults.
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// Redefine these in your program to override the defaults.
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// Number of seconds to map a diff before giving up (0 for infinity).
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this.Diff_Timeout = 1.0;
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// Cost of an empty edit operation in terms of edit characters.
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this.Diff_EditCost = 4;
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}
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// DIFF FUNCTIONS
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/**
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* The data structure representing a diff is an array of tuples:
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* [[DIFF_DELETE, 'Hello'], [DIFF_INSERT, 'Goodbye'], [DIFF_EQUAL, ' world.']]
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* which means: delete 'Hello', add 'Goodbye' and keep ' world.'
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*/
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var DIFF_DELETE = -1;
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var DIFF_INSERT = 1;
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var DIFF_EQUAL = 0;
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/** @typedef {{0: number, 1: string}} */
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diff_match_patch.Diff;
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/**
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* Find the differences between two texts. Simplifies the problem by stripping
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* any common prefix or suffix off the texts before diffing.
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* @param {string} text1 Old string to be diffed.
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* @param {string} text2 New string to be diffed.
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* @param {boolean=} opt_checklines Optional speedup flag. If present and false,
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* then don't run a line-level diff first to identify the changed areas.
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* Defaults to true, which does a faster, slightly less optimal diff.
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* @param {number} opt_deadline Optional time when the diff should be complete
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* by. Used internally for recursive calls. Users should set DiffTimeout
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* instead.
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* @return {!Array.<!diff_match_patch.Diff>} Array of diff tuples.
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*/
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diff_match_patch.prototype.diff_main = function(text1, text2, opt_checklines,
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opt_deadline) {
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// Set a deadline by which time the diff must be complete.
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if (typeof opt_deadline == 'undefined') {
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if (this.Diff_Timeout <= 0) {
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opt_deadline = Number.MAX_VALUE;
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} else {
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opt_deadline = (new Date).getTime() + this.Diff_Timeout * 1000;
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}
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}
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var deadline = opt_deadline;
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// Check for null inputs.
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if (text1 == null || text2 == null) {
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throw new Error('Null input. (diff_main)');
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}
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// Check for equality (speedup).
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if (text1 == text2) {
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if (text1) {
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return [[DIFF_EQUAL, text1]];
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}
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return [];
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}
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if (typeof opt_checklines == 'undefined') {
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opt_checklines = true;
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}
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var checklines = opt_checklines;
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// Trim off common prefix (speedup).
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var commonlength = this.diff_commonPrefix(text1, text2);
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var commonprefix = text1.substring(0, commonlength);
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text1 = text1.substring(commonlength);
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text2 = text2.substring(commonlength);
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// Trim off common suffix (speedup).
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commonlength = this.diff_commonSuffix(text1, text2);
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var commonsuffix = text1.substring(text1.length - commonlength);
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text1 = text1.substring(0, text1.length - commonlength);
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text2 = text2.substring(0, text2.length - commonlength);
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// Compute the diff on the middle block.
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var diffs = this.diff_compute_(text1, text2, checklines, deadline);
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// Restore the prefix and suffix.
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if (commonprefix) {
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diffs.unshift([DIFF_EQUAL, commonprefix]);
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}
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if (commonsuffix) {
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diffs.push([DIFF_EQUAL, commonsuffix]);
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}
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this.diff_cleanupMerge(diffs);
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return diffs;
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};
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/**
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* Find the differences between two texts. Assumes that the texts do not
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* have any common prefix or suffix.
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* @param {string} text1 Old string to be diffed.
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* @param {string} text2 New string to be diffed.
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* @param {boolean} checklines Speedup flag. If false, then don't run a
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* line-level diff first to identify the changed areas.
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* If true, then run a faster, slightly less optimal diff.
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* @param {number} deadline Time when the diff should be complete by.
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* @return {!Array.<!diff_match_patch.Diff>} Array of diff tuples.
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* @private
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*/
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diff_match_patch.prototype.diff_compute_ = function(text1, text2, checklines,
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deadline) {
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var diffs;
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if (!text1) {
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// Just add some text (speedup).
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return [[DIFF_INSERT, text2]];
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}
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if (!text2) {
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// Just delete some text (speedup).
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return [[DIFF_DELETE, text1]];
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}
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var longtext = text1.length > text2.length ? text1 : text2;
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var shorttext = text1.length > text2.length ? text2 : text1;
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var i = longtext.indexOf(shorttext);
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if (i != -1) {
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// Shorter text is inside the longer text (speedup).
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diffs = [[DIFF_INSERT, longtext.substring(0, i)],
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[DIFF_EQUAL, shorttext],
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[DIFF_INSERT, longtext.substring(i + shorttext.length)]];
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// Swap insertions for deletions if diff is reversed.
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if (text1.length > text2.length) {
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diffs[0][0] = diffs[2][0] = DIFF_DELETE;
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}
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return diffs;
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}
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if (shorttext.length == 1) {
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// Single character string.
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// After the previous speedup, the character can't be an equality.
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return [[DIFF_DELETE, text1], [DIFF_INSERT, text2]];
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}
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// Check to see if the problem can be split in two.
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var hm = this.diff_halfMatch_(text1, text2);
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if (hm) {
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// A half-match was found, sort out the return data.
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var text1_a = hm[0];
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var text1_b = hm[1];
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var text2_a = hm[2];
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var text2_b = hm[3];
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var mid_common = hm[4];
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// Send both pairs off for separate processing.
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var diffs_a = this.diff_main(text1_a, text2_a, checklines, deadline);
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var diffs_b = this.diff_main(text1_b, text2_b, checklines, deadline);
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// Merge the results.
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return diffs_a.concat([[DIFF_EQUAL, mid_common]], diffs_b);
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}
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if (checklines && text1.length > 100 && text2.length > 100) {
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return this.diff_lineMode_(text1, text2, deadline);
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}
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return this.diff_bisect_(text1, text2, deadline);
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};
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/**
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* Do a quick line-level diff on both strings, then rediff the parts for
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* greater accuracy.
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* This speedup can produce non-minimal diffs.
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* @param {string} text1 Old string to be diffed.
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* @param {string} text2 New string to be diffed.
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* @param {number} deadline Time when the diff should be complete by.
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* @return {!Array.<!diff_match_patch.Diff>} Array of diff tuples.
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* @private
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*/
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diff_match_patch.prototype.diff_lineMode_ = function(text1, text2, deadline) {
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// Scan the text on a line-by-line basis first.
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var a = this.diff_linesToChars_(text1, text2);
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text1 = a.chars1;
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text2 = a.chars2;
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var linearray = a.lineArray;
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var diffs = this.diff_main(text1, text2, false, deadline);
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// Convert the diff back to original text.
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this.diff_charsToLines_(diffs, linearray);
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// Eliminate freak matches (e.g. blank lines)
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this.diff_cleanupSemantic(diffs);
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// Rediff any replacement blocks, this time character-by-character.
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// Add a dummy entry at the end.
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diffs.push([DIFF_EQUAL, '']);
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var pointer = 0;
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var count_delete = 0;
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var count_insert = 0;
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var text_delete = '';
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var text_insert = '';
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while (pointer < diffs.length) {
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switch (diffs[pointer][0]) {
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case DIFF_INSERT:
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count_insert++;
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text_insert += diffs[pointer][1];
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break;
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case DIFF_DELETE:
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count_delete++;
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text_delete += diffs[pointer][1];
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break;
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case DIFF_EQUAL:
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// Upon reaching an equality, check for prior redundancies.
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if (count_delete >= 1 && count_insert >= 1) {
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// Delete the offending records and add the merged ones.
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diffs.splice(pointer - count_delete - count_insert,
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count_delete + count_insert);
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pointer = pointer - count_delete - count_insert;
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var a = this.diff_main(text_delete, text_insert, false, deadline);
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for (var j = a.length - 1; j >= 0; j--) {
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diffs.splice(pointer, 0, a[j]);
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}
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pointer = pointer + a.length;
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}
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count_insert = 0;
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count_delete = 0;
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text_delete = '';
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text_insert = '';
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break;
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}
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pointer++;
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}
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diffs.pop(); // Remove the dummy entry at the end.
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return diffs;
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};
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/**
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* Find the 'middle snake' of a diff, split the problem in two
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* and return the recursively constructed diff.
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* See Myers 1986 paper: An O(ND) Difference Algorithm and Its Variations.
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* @param {string} text1 Old string to be diffed.
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* @param {string} text2 New string to be diffed.
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* @param {number} deadline Time at which to bail if not yet complete.
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* @return {!Array.<!diff_match_patch.Diff>} Array of diff tuples.
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* @private
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*/
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diff_match_patch.prototype.diff_bisect_ = function(text1, text2, deadline) {
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// Cache the text lengths to prevent multiple calls.
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var text1_length = text1.length;
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var text2_length = text2.length;
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var max_d = Math.ceil((text1_length + text2_length) / 2);
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var v_offset = max_d;
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var v_length = 2 * max_d;
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var v1 = new Array(v_length);
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var v2 = new Array(v_length);
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// Setting all elements to -1 is faster in Chrome & Firefox than mixing
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// integers and undefined.
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for (var x = 0; x < v_length; x++) {
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v1[x] = -1;
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v2[x] = -1;
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}
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v1[v_offset + 1] = 0;
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v2[v_offset + 1] = 0;
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var delta = text1_length - text2_length;
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// If the total number of characters is odd, then the front path will collide
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// with the reverse path.
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var front = (delta % 2 != 0);
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// Offsets for start and end of k loop.
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// Prevents mapping of space beyond the grid.
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var k1start = 0;
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var k1end = 0;
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var k2start = 0;
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var k2end = 0;
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for (var d = 0; d < max_d; d++) {
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// Bail out if deadline is reached.
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if ((new Date()).getTime() > deadline) {
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break;
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}
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// Walk the front path one step.
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for (var k1 = -d + k1start; k1 <= d - k1end; k1 += 2) {
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var k1_offset = v_offset + k1;
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var x1;
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if (k1 == -d || (k1 != d && v1[k1_offset - 1] < v1[k1_offset + 1])) {
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x1 = v1[k1_offset + 1];
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} else {
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x1 = v1[k1_offset - 1] + 1;
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}
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var y1 = x1 - k1;
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while (x1 < text1_length && y1 < text2_length &&
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text1.charAt(x1) == text2.charAt(y1)) {
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x1++;
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y1++;
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}
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v1[k1_offset] = x1;
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if (x1 > text1_length) {
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// Ran off the right of the graph.
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k1end += 2;
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} else if (y1 > text2_length) {
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// Ran off the bottom of the graph.
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k1start += 2;
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} else if (front) {
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var k2_offset = v_offset + delta - k1;
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if (k2_offset >= 0 && k2_offset < v_length && v2[k2_offset] != -1) {
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// Mirror x2 onto top-left coordinate system.
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var x2 = text1_length - v2[k2_offset];
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if (x1 >= x2) {
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// Overlap detected.
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return this.diff_bisectSplit_(text1, text2, x1, y1, deadline);
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}
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}
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}
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}
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// Walk the reverse path one step.
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for (var k2 = -d + k2start; k2 <= d - k2end; k2 += 2) {
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var k2_offset = v_offset + k2;
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var x2;
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if (k2 == -d || (k2 != d && v2[k2_offset - 1] < v2[k2_offset + 1])) {
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x2 = v2[k2_offset + 1];
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} else {
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x2 = v2[k2_offset - 1] + 1;
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}
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var y2 = x2 - k2;
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while (x2 < text1_length && y2 < text2_length &&
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text1.charAt(text1_length - x2 - 1) ==
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text2.charAt(text2_length - y2 - 1)) {
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x2++;
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y2++;
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}
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v2[k2_offset] = x2;
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if (x2 > text1_length) {
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// Ran off the left of the graph.
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k2end += 2;
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} else if (y2 > text2_length) {
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// Ran off the top of the graph.
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k2start += 2;
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} else if (!front) {
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var k1_offset = v_offset + delta - k2;
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if (k1_offset >= 0 && k1_offset < v_length && v1[k1_offset] != -1) {
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var x1 = v1[k1_offset];
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var y1 = v_offset + x1 - k1_offset;
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// Mirror x2 onto top-left coordinate system.
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x2 = text1_length - x2;
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if (x1 >= x2) {
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// Overlap detected.
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return this.diff_bisectSplit_(text1, text2, x1, y1, deadline);
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}
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}
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}
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}
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}
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// Diff took too long and hit the deadline or
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// number of diffs equals number of characters, no commonality at all.
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return [[DIFF_DELETE, text1], [DIFF_INSERT, text2]];
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};
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/**
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* Given the location of the 'middle snake', split the diff in two parts
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* and recurse.
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* @param {string} text1 Old string to be diffed.
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* @param {string} text2 New string to be diffed.
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* @param {number} x Index of split point in text1.
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* @param {number} y Index of split point in text2.
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* @param {number} deadline Time at which to bail if not yet complete.
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* @return {!Array.<!diff_match_patch.Diff>} Array of diff tuples.
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* @private
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*/
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diff_match_patch.prototype.diff_bisectSplit_ = function(text1, text2, x, y,
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deadline) {
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var text1a = text1.substring(0, x);
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var text2a = text2.substring(0, y);
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var text1b = text1.substring(x);
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var text2b = text2.substring(y);
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// Compute both diffs serially.
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var diffs = this.diff_main(text1a, text2a, false, deadline);
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var diffsb = this.diff_main(text1b, text2b, false, deadline);
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return diffs.concat(diffsb);
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};
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/**
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* Split two texts into an array of strings. Reduce the texts to a string of
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* hashes where each Unicode character represents one line.
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* @param {string} text1 First string.
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* @param {string} text2 Second string.
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* @return {{chars1: string, chars2: string, lineArray: !Array.<string>}}
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* An object containing the encoded text1, the encoded text2 and
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* the array of unique strings.
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* The zeroth element of the array of unique strings is intentionally blank.
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* @private
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*/
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diff_match_patch.prototype.diff_linesToChars_ = function(text1, text2) {
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var lineArray = []; // e.g. lineArray[4] == 'Hello\n'
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var lineHash = {}; // e.g. lineHash['Hello\n'] == 4
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// '\x00' is a valid character, but various debuggers don't like it.
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// So we'll insert a junk entry to avoid generating a null character.
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lineArray[0] = '';
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/**
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* Split a text into an array of strings. Reduce the texts to a string of
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* hashes where each Unicode character represents one line.
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* Modifies linearray and linehash through being a closure.
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* @param {string} text String to encode.
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* @return {string} Encoded string.
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* @private
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*/
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function diff_linesToCharsMunge_(text) {
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var chars = '';
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// Walk the text, pulling out a substring for each line.
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// text.split('\n') would would temporarily double our memory footprint.
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// Modifying text would create many large strings to garbage collect.
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var lineStart = 0;
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var lineEnd = -1;
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// Keeping our own length variable is faster than looking it up.
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var lineArrayLength = lineArray.length;
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while (lineEnd < text.length - 1) {
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lineEnd = text.indexOf('\n', lineStart);
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if (lineEnd == -1) {
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lineEnd = text.length - 1;
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}
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var line = text.substring(lineStart, lineEnd + 1);
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lineStart = lineEnd + 1;
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if (lineHash.hasOwnProperty ? lineHash.hasOwnProperty(line) :
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(lineHash[line] !== undefined)) {
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chars += String.fromCharCode(lineHash[line]);
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} else {
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chars += String.fromCharCode(lineArrayLength);
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lineHash[line] = lineArrayLength;
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lineArray[lineArrayLength++] = line;
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}
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}
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return chars;
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}
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var chars1 = diff_linesToCharsMunge_(text1);
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var chars2 = diff_linesToCharsMunge_(text2);
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return {chars1: chars1, chars2: chars2, lineArray: lineArray};
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};
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/**
|
|
* 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 = [];
|
|
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.
|
|
switch (op) {
|
|
case DIFF_INSERT:
|
|
html[x] = '<ins>' + data + '</ins>';
|
|
break;
|
|
case DIFF_DELETE:
|
|
html[x] = '<del>' + data + '</del>';
|
|
break;
|
|
case DIFF_EQUAL:
|
|
html[x] = data;
|
|
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;
|
|
};
|
|
|
|
// 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; |