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