Файл: mailist/wys/jscripts/tiny_mce/plugins/devkit/jscripts/diff.js
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<?php
// 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] == "Hellon"
var linehash = new Object(); // linehash["Hellon"] == 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
?>