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diff_match_patch.php
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diff_match_patch.php
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			<?php
			/**
			* Diff Match and Patch
			*
			* Copyright 2006 Google Inc.
			* http://code.google.com/p/google-diff-match-patch/
			*
			* php port by Tobias Buschor shwups.ch
			*
			* Licensed under the Apache License, Version 2.0 (the "License");
			* you may not use this file except in compliance with the License.
			* You may obtain a copy of the License at
			*
			* http://www.apache.org/licenses/LICENSE-2.0
			*
			* Unless required by applicable law or agreed to in writing, software
			* distributed under the License is distributed on an "AS IS" BASIS,
			* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
			* See the License for the specific language governing permissions and
			* limitations under the License.
			*/

			/**
			* @fileoverview Computes the difference between two texts to create a patch.
			* Applies the patch onto another text, allowing for errors.
			* @author fraser@google.com (Neil Fraser)
			*/

			/**
			* Class containing the diff, match and patch methods.
			* @constructor
			*/
			class diff_match_patch {

			// Defaults.
			// Redefine these in your program to override the defaults.

			// Number of seconds to map a diff before giving up (0 for infinity).
			public $Diff_Timeout = 1.0;
			// Cost of an empty edit operation in terms of edit characters.
			public $Diff_EditCost = 4;
			// The size beyond which the double-ended diff activates.
			// Double-ending is twice as fast, but less accurate.
			public $Diff_DualThreshold = 32;
			// At what point is no match declared (0.0 = perfection, 1.0 = very loose).
			public $Match_Threshold = 0.5;
			// How far to search for a match (0 = exact location, 1000+ = broad match).
			// A match this many characters away from the expected location will add
			// 1.0 to the score (0.0 is a perfect match).
			public $Match_Distance = 1000;
			// When deleting a large block of text (over ~64 characters), how close does
			// the contents have to match the expected contents. (0.0 = perfection,
			// 1.0 = very loose). Note that Match_Threshold controls how closely the
			// end points of a delete need to match.
			public $Patch_DeleteThreshold = 0.5;
			// Chunk size for context length.
			public $Patch_Margin = 4;

			/**
			* Compute the number of bits in an int.
			* The normal answer for JavaScript is 32.
			* @return {number} Max bits

			function getMaxBits() {
			var maxbits = 0;
			var oldi = 1;
			var newi = 2;
			while (oldi != newi) {
			maxbits++;
			oldi = newi;
			newi = newi << 1;
			}
			return maxbits;
			}
			// How many bits in a number?
			this.Match_MaxBits = getMaxBits();
			*/
			// DIFF FUNCTIONS

			/**
			* Find the differences between two texts. Simplifies the problem by stripping
			* any common prefix or suffix off the texts before diffing.
			* @param {string} text1 Old string to be diffed.
			* @param {string} text2 New string to be diffed.
			* @param {boolean} opt_checklines Optional speedup flag. If present and false,
			* then don't run a line-level diff first to identify the changed areas.
			* Defaults to true, which does a faster, slightly less optimal diff
			* @return {Array.<Array.<number\|string>>} Array of diff tuples.
			*/
			function diff_main($text1, $text2, $checklines = true) {
			// Check for equality (speedup)
			if ($text1 === $text2) {
			return array ( array ( DIFF_EQUAL, $text1) );
			}

			// Trim off common prefix (speedup)
			$commonlength = $this->diff_commonPrefix($text1, $text2);
			$commonprefix = mb_substr($text1, 0, $commonlength);
			$text1 = mb_substr($text1, $commonlength);
			$text2 = mb_substr($text2, $commonlength);

			// Trim off common suffix (speedup)
			$commonlength = $this->diff_commonSuffix($text1, $text2);
			$commonsuffix = mb_substr($text1, mb_strlen($text1) - $commonlength);
			$text1 = mb_substr($text1, 0, mb_strlen($text1) - $commonlength);
			$text2 = mb_substr($text2, 0, mb_strlen($text2) - $commonlength);

			// Compute the diff on the middle block
			$diffs = $this->diff_compute($text1, $text2, $checklines);

			// Restore the prefix and suffix
			if ($commonprefix !== '') {
			array_unshift($diffs, array ( DIFF_EQUAL, $commonprefix ));
			}
			if ($commonsuffix !== '') {
			array_push($diffs, array ( DIFF_EQUAL, $commonsuffix ));
			}
			$this->diff_cleanupMerge($diffs);
			return $diffs;
			}

			/**
			* Find the differences between two texts. Assumes that the texts do not
			* have any common prefix or suffix.
			* @param {string} text1 Old string to be diffed.
			* @param {string} text2 New string to be diffed.
			* @param {boolean} checklines Speedup flag. If false, then don't run a
			* line-level diff first to identify the changed areas.
			* If true, then run a faster, slightly less optimal diff
			* @return {Array.<Array.<number\|string>>} Array of diff tuples.
			* @private
			*/
			function diff_compute($text1, $text2, $checklines) {

			if ($text1 === '') {
			// Just add some text (speedup)
			return array ( array ( DIFF_INSERT, $text2 ) );
			}

			if ($text2 === '') {
			// Just delete some text (speedup)
			return array ( array ( DIFF_DELETE, $text1 ) );
			}

			$longtext = mb_strlen($text1) > mb_strlen($text2) ? $text1 : $text2;
			$shorttext = mb_strlen($text1) > mb_strlen($text2) ? $text2 : $text1;
			$i = mb_strpos($longtext, $shorttext);
			if ($i !== false) {
			// Shorter text is inside the longer text (speedup)
			$diffs = array (
			array ( DIFF_INSERT, mb_substr($longtext, 0, $i) ),
			array ( DIFF_EQUAL, $shorttext ),
			array ( DIFF_INSERT, mb_substr($longtext, $i +mb_strlen($shorttext)) )
			);

			// Swap insertions for deletions if diff is reversed.
			if (mb_strlen($text1) > mb_strlen($text2)) {
			$diffs[0][0] = $diffs[2][0] = DIFF_DELETE;
			}
			return $diffs;
			}
			$longtext = $shorttext = null; // Garbage collect

			// Check to see if the problem can be split in two.
			$hm = $this->diff_halfMatch($text1, $text2);
			if ($hm) {
			// A half-match was found, sort out the return data.
			$text1_a = $hm[0];
			$text1_b = $hm[1];
			$text2_a = $hm[2];
			$text2_b = $hm[3];
			$mid_common = $hm[4];
			// Send both pairs off for separate processing.
			$diffs_a = $this->diff_main($text1_a, $text2_a, $checklines);
			$diffs_b = $this->diff_main($text1_b, $text2_b, $checklines);
			// Merge the results.
			return array_merge($diffs_a, array (
			array (
			DIFF_EQUAL,
			$mid_common
			)
			), $diffs_b);
			}

			// Perform a real diff.
			if ($checklines && (mb_strlen($text1) < 100 \|\| mb_strlen($text2) < 100)) {
			// Too trivial for the overhead.
			$checklines = false;
			}
			$linearray = null;
			if ($checklines) {
			// Scan the text on a line-by-line basis first.
			$a = $this->diff_linesToChars($text1, $text2);
			$text1 = $a[0];
			$text2 = $a[1];
			$linearray = $a[2];
			}
			$diffs = $this->diff_map($text1, $text2);
			if (!$diffs) {
			// No acceptable result.
			$diffs = array (
			array (
			DIFF_DELETE,
			$text1
			),
			array (
			DIFF_INSERT,
			$text2
			)
			);
			}
			if ($checklines) {
			// Convert the diff back to original text.
			$this->diff_charsToLines($diffs, $linearray);
			// Eliminate freak matches (e.g. blank lines)
			$this->diff_cleanupSemantic($diffs);

			// Rediff any replacement blocks, this time character-by-character.
			// Add a dummy entry at the end.
			array_push($diffs, array (
			DIFF_EQUAL,
			''
			));
			$pointer = 0;
			$count_delete = 0;
			$count_insert = 0;
			$text_delete = '';
			$text_insert = '';
			while ($pointer < count($diffs)) {
			switch ($diffs[$pointer][0]) {
			case DIFF_INSERT :
			$count_insert++;
			$text_insert .= $diffs[$pointer][1];
			break;
			case DIFF_DELETE :
			$count_delete++;
			$text_delete .= $diffs[$pointer][1];
			break;
			case DIFF_EQUAL :
			// Upon reaching an equality, check for prior redundancies.
			if ($count_delete >= 1 && $count_insert >= 1) {
			// Delete the offending records and add the merged ones.
			$a = $this->diff_main($text_delete, $text_insert, false);
			array_splice($diffs, $pointer - $count_delete - $count_insert, $count_delete + $count_insert);

			$pointer = $pointer - $count_delete - $count_insert;
			for ($j = count($a) - 1; $j >= 0; $j--) {
			array_splice($diffs, $pointer, 0, array($a[$j]));
			}
			$pointer = $pointer +count($a);
			}
			$count_insert = 0;
			$count_delete = 0;
			$text_delete = '';
			$text_insert = '';
			break;
			}
			$pointer++;
			}
			array_pop($diffs); // Remove the dummy entry at the end.
			}
			return $diffs;
			}

			/**
			* Split two texts into an array of strings. Reduce the texts to a string of
			* hashes where each Unicode character represents one line.
			* @param {string} text1 First string.
			* @param {string} text2 Second string.
			* @return {Array.<string\|Array.<string>>} Three element Array, containing the
			* encoded text1, the encoded text2 and the array of unique strings. The
			* zeroth element of the array of unique strings is intentionally blank.
			* @private
			*/
			function diff_linesToChars($text1, $text2) {
			$lineArray = array(); // e.g. lineArray[4] == 'Hello\n'
			$lineHash = array(); // e.g. lineHash['Hello\n'] == 4

			// '\x00' is a valid character, but various debuggers don't like it.
			// So we'll insert a junk entry to avoid generating a null character.
			$lineArray[0] = '';

			$chars1 = $this->diff_linesToCharsMunge($text1, $lineArray, $lineHash);
			$chars2 = $this->diff_linesToCharsMunge($text2, $lineArray, $lineHash);
			return array (
			$chars1,
			$chars2,
			$lineArray
			);
			}

			/**
			* Split a text into an array of strings. Reduce the texts to a string of
			* hashes where each Unicode character represents one line.
			* Modifies linearray and linehash through being a closure.
			* @param {string} text String to encode
			* @return {string} Encoded string
			* @private
			*/
			function diff_linesToCharsMunge($text, &$lineArray, &$lineHash) {
			$chars = '';
			// Walk the text, pulling out a mb_substring for each line.
			// text.split('\n') would would temporarily double our memory footprint.
			// Modifying text would create many large strings to garbage collect.
			$lineStart = 0;
			$lineEnd = -1;
			// Keeping our own length variable is faster than looking it up.
			$lineArrayLength = count($lineArray);
			while ($lineEnd < mb_strlen($text) - 1) {
			$lineEnd = mb_strpos($text, "\n", $lineStart);
			if ($lineEnd === false) {
			$lineEnd = mb_strlen($text) - 1;
			}
			$line = mb_substr($text, $lineStart, $lineEnd +1 -$lineStart);
			$lineStart = $lineEnd +1;

			if ( isset($lineHash[$line]) ) {
			$chars .= mb_chr($lineHash[$line]);
			} else {
			$chars .= mb_chr($lineArrayLength);
			$lineHash[$line] = $lineArrayLength;
			$lineArray[$lineArrayLength++] = $line;
			}
			}
			return $chars;
			}
			/**
			* Rehydrate the text in a diff from a string of line hashes to real lines of
			* text.
			* @param {Array.<Array.<number\|string>>} diffs Array of diff tuples.
			* @param {Array.<string>} lineArray Array of unique strings.
			* @private
			*/
			function diff_charsToLines(&$diffs, $lineArray) {
			for ($x = 0; $x < count($diffs); $x++) {
			$chars = $diffs[$x][1];
			$text = array ();
			for ($y = 0; $y < mb_strlen($chars); $y++) {
			$text[$y] = $lineArray[charCodeAt($chars, $y)];
			}
			$diffs[$x][1] = implode('',$text);
			}
			}

			/**
			* Explore the intersection points between the two texts.
			* @param {string} text1 Old string to be diffed.
			* @param {string} text2 New string to be diffed.
			* @return {Array.<Array.<number\|string>>?} Array of diff tuples or null if no
			* diff available.
			* @private
			*/
			function diff_map($text1, $text2) {
			// Don't run for too long.
			$ms_end = microtime(true) + $this->Diff_Timeout;

			// Cache the text lengths to prevent multiple calls.
			$text1_length = mb_strlen($text1);
			$text2_length = mb_strlen($text2);
			$max_d = $text1_length + $text2_length -1;
			$doubleEnd = $this->Diff_DualThreshold * 2 < $max_d;
			$v_map1 = array();
			$v_map2 = array();
			$v1 = array();
			$v2 = array();
			$v1[1] = 0;
			$v2[1] = 0;
			$x = null;
			$y = null;
			$footstep = null; // Used to track overlapping paths.
			$footsteps = array();
			$done = false;
			// Safari 1.x doesn't have hasOwnProperty
			//? $hasOwnProperty = !!(footsteps.hasOwnProperty);
			// If the total number of characters is odd, then the front path will collide
			// with the reverse path.
			$front = ($text1_length + $text2_length) % 2;
			for ($d = 0; $d < $max_d; $d++) {
			// Bail out if timeout reached.
			if ($this->Diff_Timeout > 0 && microtime(true) > $ms_end) {
			return null; // zzz
			}

			// Walk the front path one step.
			$v_map1[$d] = array ();
			for ($k = -$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 - $k;
			if ($doubleEnd) {
			$footstep = $x . ',' . $y;
			if ($front && isset ($footsteps[$footstep])) {
			$done = true;
			}
			if (!$front) {
			$footsteps[$footstep] = $d;
			}
			}
			while (!$done && ($x < $text1_length) && ($y < $text2_length) && (mb_substr($text1, $x, 1) == mb_substr($text2, $y, 1)) ) {
			$x++;
			$y++;
			if ($doubleEnd) {
			$footstep = $x . ',' . $y;
			if ($front && isset ($footsteps[$footstep])) {
			$done = true;
			}
			if (!$front) {
			$footsteps[$footstep] = $d;
			}
			}
			}
			$v1[$k] = $x;
			$v_map1[$d][$x . ',' . $y] = true;
			if ($x == $text1_length && $y == $text2_length) {
			// Reached the end in single-path mode.
			return $this->diff_path1($v_map1, $text1, $text2);
			}
			elseif ($done) {
			// Front path ran over reverse path.

			$v_map2 = array_slice($v_map2, 0, $footsteps[$footstep] + 1);
			$a = $this->diff_path1($v_map1, mb_substr($text1, 0, $x), mb_substr($text2, 0, $y));

			return array_merge($a, $this->diff_path2($v_map2, mb_substr($text1, $x), mb_substr($text2, $y)));
			}
			}

			if ($doubleEnd) {
			// Walk the reverse path one step.
			$v_map2[$d] = array();
			for ($k = -$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 && isset ($footsteps[$footstep])) {
			$done = true;
			}
			if ($front) {
			$footsteps[$footstep] = $d;
			}
			while (!$done && $x < $text1_length && $y < $text2_length && mb_substr($text1, $text1_length - $x -1, 1) == mb_substr($text2, $text2_length - $y -1, 1) ) {
			$x++;
			$y++;
			$footstep = ($text1_length - $x) . ',' . ($text2_length - $y);
			if (!$front && isset ($footsteps[$footstep])) {
			$done = true;
			}
			if ($front) {
			$footsteps[$footstep] = $d;
			}
			}
			$v2[$k] = $x;
			$v_map2[$d][$x . ',' . $y] = true;
			if ($done) {
			// Reverse path ran over front path.
			$v_map1 = array_slice($v_map1, 0, $footsteps[$footstep] + 1);
			$a = $this->diff_path1($v_map1, mb_substr($text1, 0, $text1_length - $x), mb_substr($text2, 0, $text2_length - $y));
			return array_merge($a, $this->diff_path2($v_map2, mb_substr($text1, $text1_length - $x), mb_substr($text2, $text2_length - $y)));
			}
			}
			}
			}
			// Number of diffs equals number of characters, no commonality at all.
			return null;
			}

			/**
			* Work from the middle back to the start to determine the path.
			* @param {Array.<Object>} v_map Array of paths.ers
			* @param {string} text1 Old string fragment to be diffed.
			* @param {string} text2 New string fragment to be diffed.
			* @return {Array.<Array.<number\|string>>} Array of diff tuples.
			* @private
			*/
			function diff_path1($v_map, $text1, $text2) {
			$path = array ();
			$x = mb_strlen($text1);
			$y = mb_strlen($text2);
			/** @type {number?} */
			$last_op = null;
			for ($d = count($v_map) - 2; $d >= 0; $d--) {
			while (1) {
			if (isset ($v_map[$d][($x -1) . ',' . $y])) {
			$x--;
			if ($last_op === DIFF_DELETE) {
			$path[0][1] = mb_substr($text1, $x, 1) . $path[0][1];
			} else {
			array_unshift($path, array (
			DIFF_DELETE,
			mb_substr($text1, $x, 1)
			));
			}
			$last_op = DIFF_DELETE;
			break;
			} elseif (isset ($v_map[$d][$x . ',' . ($y -1)])) {
			$y--;
			if ($last_op === DIFF_INSERT) {
			$path[0][1] = mb_substr($text2, $y, 1) . $path[0][1];
			} else {
			array_unshift($path, array (
			DIFF_INSERT,
			mb_substr($text2, $y, 1)
			));
			}
			$last_op = DIFF_INSERT;
			break;
			} else {
			$x--;
			$y--;
			//if (text1.charAt(x) != text2.charAt(y)) {
			// throw new Error('No diagonal. Can\'t happen. (diff_path1)');
			//}
			if ($last_op === DIFF_EQUAL) {
			$path[0][1] = mb_substr($text1, $x, 1) . $path[0][1];
			} else {
			array_unshift($path, array (
			DIFF_EQUAL,
			mb_substr($text1, $x, 1)
			));
			}
			$last_op = DIFF_EQUAL;
			}
			}
			}
			return $path;
			}

			/**
			* Work from the middle back to the end to determine the path.
			* @param {Array.<Object>} v_map Array of paths.
			* @param {string} text1 Old string fragment to be diffed.
			* @param {string} text2 New string fragment to be diffed.
			* @return {Array.<Array.<number\|string>>} Array of diff tuples.
			* @private
			*/
			function diff_path2($v_map, $text1, $text2) {
			$path = array ();
			$pathLength = 0;
			$x = mb_strlen($text1);
			$y = mb_strlen($text2);
			/** @type {number?} */
			$last_op = null;
			for ($d = count($v_map) - 2; $d >= 0; $d--) {
			while (1) {
			if (isset ($v_map[$d][($x -1) . ',' . $y])) {
			$x--;
			if ($last_op === DIFF_DELETE) {
			$path[$pathLength -1][1] .= $text1[mb_strlen($text1) - $x -1];
			} else {
			$path[$pathLength++] = array (
			DIFF_DELETE,
			$text1[mb_strlen($text1) - $x -1]
			);
			}
			$last_op = DIFF_DELETE;
			break;
			}
			elseif (isset ($v_map[$d][$x . ',' . ($y -1)])) {
			$y--;
			if ($last_op === DIFF_INSERT) {
			$path[$pathLength -1][1] .= $text2[mb_strlen($text2) - $y -1];
			} else {
			$path[$pathLength++] = array (
			DIFF_INSERT,
			$text2[mb_strlen($text2) - $y -1]
			);
			}
			$last_op = DIFF_INSERT;
			break;
			} else {
			$x--;
			$y--;
			//if (text1.charAt(text1.length - x - 1) !=
			// text2.charAt(text2.length - y - 1)) {
			// throw new Error('No diagonal. Can\'t happen. (diff_path2)');
			//}
			if ($last_op === DIFF_EQUAL) {
			$path[$pathLength -1][1] .= $text1[mb_strlen($text1) - $x -1];
			} else {
			$path[$pathLength++] = array (
			DIFF_EQUAL,
			$text1[mb_strlen($text1) - $x -1]
			);
			}
			$last_op = DIFF_EQUAL;
			}
			}
			}
			return $path;
			}

			/**
			* 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.
			*/
			function diff_commonPrefix($text1, $text2) {
			for ($i = 0; 1; $i++) {
			$t1 = mb_substr($text1, $i, 1);
			$t2 = mb_substr($text2, $i, 1);
			if($t1==='' \|\| $t2==='' \|\| $t1 !== $t2 ){
			return $i;
			}
			}
			}

			/**
			* 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.
			*/
			function diff_commonSuffix($text1, $text2) {
			return $this->diff_commonPrefix( strrev($text1), strrev($text2) );
			}

			/**
			* Do the two texts share a mb_substring which is at least half the length of the
			* longer text?
			* @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.
			*/
			function diff_halfMatch($text1, $text2) {
			$longtext = mb_strlen($text1) > mb_strlen($text2) ? $text1 : $text2;
			$shorttext = mb_strlen($text1) > mb_strlen($text2) ? $text2 : $text1;
			if (mb_strlen($longtext) < 10 \|\| mb_strlen($shorttext) < 1) {
			return null; // Pointless.
			}

			// First check if the second quarter is the seed for a half-match.
			$hm1 = $this->diff_halfMatchI($longtext, $shorttext, ceil(mb_strlen($longtext) / 4));
			// Check again based on the third quarter.
			$hm2 = $this->diff_halfMatchI($longtext, $shorttext, ceil(mb_strlen($longtext) / 2));

			if (!$hm1 && !$hm2) {
			return null;
			} elseif (!$hm2) {
			$hm = $hm1;
			} elseif (!$hm1) {
			$hm = $hm2;
			} else {
			// Both matched. Select the longest.
			$hm = mb_strlen($hm1[4]) > mb_strlen($hm2[4]) ? $hm1 : $hm2;
			}

			// A half-match was found, sort out the return data.
			if (mb_strlen($text1) > mb_strlen($text2)) {
			$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];
			}
			$mid_common = $hm[4];
			return array( $text1_a, $text1_b, $text2_a, $text2_b, $mid_common );
			}

			/**
			* Does a mb_substring of shorttext exist within longtext such that the mb_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 mb_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 mb_substring at position i as a seed.
			$seed = mb_substr($longtext, $i, floor(mb_strlen($longtext) / 4));

			$j = -1;
			$best_common = '';
			$best_longtext_a = null;
			$best_longtext_b = null;
			$best_shorttext_a = null;
			$best_shorttext_b = null;
			while ( ($j = mb_strpos($shorttext, $seed, $j + 1)) !== false ) {
			$prefixLength = $this->diff_commonPrefix(mb_substr($longtext, $i), mb_substr($shorttext, $j));
			$suffixLength = $this->diff_commonSuffix(mb_substr($longtext, 0, $i), mb_substr($shorttext, 0, $j));
			if (mb_strlen($best_common) < $suffixLength + $prefixLength) {
			$best_common = mb_substr($shorttext, $j - $suffixLength, $suffixLength) . mb_substr($shorttext, $j, $prefixLength);
			$best_longtext_a = mb_substr($longtext, 0, $i - $suffixLength);
			$best_longtext_b = mb_substr($longtext, $i + $prefixLength);
			$best_shorttext_a = mb_substr($shorttext, 0, $j - $suffixLength);
			$best_shorttext_b = mb_substr($shorttext, $j + $prefixLength);
			}
			}
			if (mb_strlen($best_common) >= mb_strlen($longtext) / 2) {
			return array (
			$best_longtext_a,
			$best_longtext_b,
			$best_shorttext_a,
			$best_shorttext_b,
			$best_common
			);
			} else {
			return null;
			}
			}

			/**
			* Reduce the number of edits by eliminating semantically trivial equalities.
			* @param {Array.<Array.<number\|string>>} diffs Array of diff tuples.
			*/
			function diff_cleanupSemantic(&$diffs) {
			$changes = false;
			$equalities = array (); // Stack of indices where equalities are found.
			$equalitiesLength = 0; // Keeping our own length var is faster in JS.
			$lastequality = null; // Always equal to equalities[equalitiesLength-1][1]
			$pointer = 0; // Index of current position.
			// Number of characters that changed prior to the equality.
			$length_changes1 = 0;
			// Number of characters that changed after the equality.
			$length_changes2 = 0;
			while ($pointer < count($diffs)) {
			if ($diffs[$pointer][0] == DIFF_EQUAL) { // equality found
			$equalities[$equalitiesLength++] = $pointer;
			$length_changes1 = $length_changes2;
			$length_changes2 = 0;
			$lastequality = $diffs[$pointer][1];
			} else { // an insertion or deletion
			$length_changes2 += mb_strlen($diffs[$pointer][1]);
			if ($lastequality !== null && (mb_strlen($lastequality) <= $length_changes1) && (mb_strlen($lastequality) <= $length_changes2)) {
			// Duplicate record
			$zzz_diffs = array_splice($diffs, $equalities[$equalitiesLength -1], 0, array(array (
			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_changes1 = 0; // Reset the counters.
			$length_changes2 = 0;
			$lastequality = null;
			$changes = true;
			}
			}
			$pointer++;
			}
			if ($changes) {
			$this->diff_cleanupMerge($diffs);
			}
			$this->diff_cleanupSemanticLossless($diffs);
			}

			/**
			* 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.<Array.<number\|string>>} diffs Array of diff tuples.
			*/
			function diff_cleanupSemanticLossless(&$diffs) {

			$pointer = 1;
			// Intentionally ignore the first and last element (don't need checking).
			while ($pointer < count($diffs) - 1) {
			if ($diffs[$pointer -1][0] == DIFF_EQUAL && $diffs[$pointer +1][0] == DIFF_EQUAL) {
			// This is a single edit surrounded by equalities.
			$equality1 = $diffs[$pointer -1][1];
			$edit = $diffs[$pointer][1];
			$equality2 = $diffs[$pointer +1][1];

			// First, shift the edit as far left as possible.
			$commonOffset = $this->diff_commonSuffix($equality1, $edit);
			if ($commonOffset !== '') {
			$commonString = mb_substr($edit, mb_strlen($edit) - $commonOffset);
			$equality1 = mb_substr($equality1, 0, mb_strlen($equality1) - $commonOffset);
			$edit = $commonString . mb_substr($edit, 0, mb_strlen($edit) - $commonOffset);
			$equality2 = $commonString . $equality2;
			}

			// Second, step character by character right, looking for the best fit.
			$bestEquality1 = $equality1;
			$bestEdit = $edit;
			$bestEquality2 = $equality2;
			$bestScore = $this->diff_cleanupSemanticScore($equality1, $edit) + $this->diff_cleanupSemanticScore($edit, $equality2);
			while (isset($equality2[0]) && $edit[0] === $equality2[0]) {
			$equality1 .= $edit[0];
			$edit = mb_substr($edit, 1) . $equality2[0];
			$equality2 = mb_substr($equality2, 1);
			$score = $this->diff_cleanupSemanticScore($equality1, $edit) + $this->diff_cleanupSemanticScore($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 {
			$zzz_diffs = array_splice($diffs, $pointer -1, 1);
			$pointer--;
			}
			$diffs[$pointer][1] = $bestEdit;
			if ($bestEquality2) {
			$diffs[$pointer +1][1] = $bestEquality2;
			} else {
			$zzz_diffs = array_splice($diffs, $pointer +1, 1);
			$pointer--;
			}
			}
			}
			$pointer++;
			}
			}

			/**
			* Given two strings, compute a score representing whether the internal
			* boundary falls on logical boundaries.
			* Scores range from 5 (best) to 0 (worst).
			* Closure, makes reference to regex patterns defined above.
			* @param {string} one First string
			* @param {string} two Second string
			* @return {number} The score.
			*/
			function diff_cleanupSemanticScore($one, $two) {
			// Define some regex patterns for matching boundaries.
			$punctuation = '/[^a-zA-Z0-9]/';
			$whitespace = '/\s/';
			$linebreak = '/[\r\n]/';
			$blanklineEnd = '/\n\r?\n$/';
			$blanklineStart = '/^\r?\n\r?\n/';

			if (!$one \|\| !$two) {
			// Edges are the best.
			return 5;
			}

			// 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.
			$score = 0;
			// One point for non-alphanumeric.
			if (preg_match($punctuation, $one[mb_strlen($one) - 1]) \|\| preg_match($punctuation, $two[0])) {
			$score++;
			// Two points for whitespace.
			if (preg_match($whitespace, $one[mb_strlen($one) - 1] ) \|\| preg_match($whitespace, $two[0])) {
			$score++;
			// Three points for line breaks.
			if (preg_match($linebreak, $one[mb_strlen($one) - 1]) \|\| preg_match($linebreak, $two[0])) {
			$score++;
			// Four points for blank lines.
			if (preg_match($blanklineEnd, $one) \|\| preg_match($blanklineStart, $two)) {
			$score++;
			}
			}
			}
			}
			return $score;
			}

			/**
			* Reduce the number of edits by eliminating operationally trivial equalities.
			* @param {Array.<Array.<number\|string>>} diffs Array of diff tuples.
			*/
			function diff_cleanupEfficiency(&$diffs) {
			$changes = false;
			$equalities = array (); // Stack of indices where equalities are found.
			$equalitiesLength = 0; // Keeping our own length var is faster in JS.
			$lastequality = ''; // Always equal to equalities[equalitiesLength-1][1]
			$pointer = 0; // Index of current position.
			// Is there an insertion operation before the last equality.
			$pre_ins = false;
			// Is there a deletion operation before the last equality.
			$pre_del = false;
			// Is there an insertion operation after the last equality.
			$post_ins = false;
			// Is there a deletion operation after the last equality.
			$post_del = false;
			while ($pointer < count($diffs)) {
			if ($diffs[$pointer][0] == DIFF_EQUAL) { // equality found
			if (mb_strlen($diffs[$pointer][1]) < $this->Diff_EditCost && ($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 = '';
			}
			$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 && $post_del) \|\| ((mb_strlen($lastequality) < $this->Diff_EditCost / 2) && ($pre_ins + $pre_del + $post_ins + $post_del) == 3))) {
			// Duplicate record
			$zzz_diffs = array_splice($diffs, $equalities[$equalitiesLength -1], 0, array(array (
			DIFF_DELETE,
			$lastequality
			)));
			// Change second copy to insert.
			$diffs[$equalities[$equalitiesLength -1] + 1][0] = DIFF_INSERT;
			$equalitiesLength--; // Throw away the equality we just deleted;
			$lastequality = '';
			if ($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.<Array.<number\|string>>} diffs Array of diff tuples.
			*/
			function diff_cleanupMerge(&$diffs) {
			array_push($diffs, array ( DIFF_EQUAL, '' )); // Add a dummy entry at the end.
			$pointer = 0;
			$count_delete = 0;
			$count_insert = 0;
			$text_delete = '';
			$text_insert = '';
			$commonlength = null;
			while ($pointer < count($diffs)) {
			switch ($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 !== 0 \|\| $count_insert !== 0) {
			if ($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 - $count_insert -1][1] .= mb_substr($text_insert, 0, $commonlength);
			} else {
			array_splice($diffs, 0, 0, array(array (
			DIFF_EQUAL,
			mb_substr($text_insert, 0, $commonlength)
			)));
			$pointer++;
			}
			$text_insert = mb_substr($text_insert, $commonlength);
			$text_delete = mb_substr($text_delete, $commonlength);
			}
			// Factor out any common suffixies.
			$commonlength = $this->diff_commonSuffix($text_insert, $text_delete);
			if ($commonlength !== 0) {
			$diffs[$pointer][1] = mb_substr($text_insert, mb_strlen($text_insert) - $commonlength) . $diffs[$pointer][1];
			$text_insert = mb_substr($text_insert, 0, mb_strlen($text_insert) - $commonlength);
			$text_delete = mb_substr($text_delete, 0, mb_strlen($text_delete) - $commonlength);
			}
			}
			// Delete the offending records and add the merged ones.
			if ($count_delete === 0) {
			array_splice($diffs, $pointer-$count_delete-$count_insert, $count_delete+$count_insert, array(array(
			DIFF_INSERT,
			$text_insert
			)));
			} elseif ($count_insert === 0) {
			array_splice($diffs, $pointer-$count_delete-$count_insert, $count_delete+$count_insert, array(array(
			DIFF_DELETE,
			$text_delete
			)));
			} else {
			array_splice($diffs, $pointer-$count_delete-$count_insert, $count_delete+$count_insert, array(array(
			DIFF_DELETE,
			$text_delete
			), array (
			DIFF_INSERT,
			$text_insert
			)));
			}
			$pointer = $pointer - $count_delete - $count_insert + ($count_delete ? 1 : 0) + ($count_insert ? 1 : 0) + 1;
			} elseif ($pointer !== 0 && $diffs[$pointer -1][0] == DIFF_EQUAL) {
			// Merge this equality with the previous one.
			$diffs[$pointer -1][1] .= $diffs[$pointer][1];
			array_splice($diffs, $pointer, 1);
			} else {
			$pointer++;
			}
			$count_insert = 0;
			$count_delete = 0;
			$text_delete = '';
			$text_insert = '';
			break;
			}
			}
			if ($diffs[count($diffs) - 1][1] === '') {
			array_pop($diffs); // 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
			$changes = false;
			$pointer = 1;
			// Intentionally ignore the first and last element (don't need checking).
			while ($pointer < count($diffs) - 1) {
			if ($diffs[$pointer-1][0] == DIFF_EQUAL && $diffs[$pointer+1][0] == DIFF_EQUAL) {
			// This is a single edit surrounded by equalities.
			if ( mb_substr($diffs[$pointer][1], mb_strlen($diffs[$pointer][1]) - mb_strlen($diffs[$pointer -1][1])) == $diffs[$pointer -1][1]) {
			// Shift the edit over the previous equality.
			$diffs[$pointer][1] = $diffs[$pointer -1][1] . mb_substr($diffs[$pointer][1], 0, mb_strlen($diffs[$pointer][1]) - mb_strlen($diffs[$pointer -1][1]));
			$diffs[$pointer +1][1] = $diffs[$pointer -1][1] . $diffs[$pointer +1][1];
			array_splice($diffs, $pointer -1, 1);
			$changes = true;
			} elseif (mb_substr($diffs[$pointer][1], 0, mb_strlen($diffs[$pointer +1][1])) == $diffs[$pointer +1][1]) {
			// Shift the edit over the next equality.
			$diffs[$pointer -1][1] .= $diffs[$pointer +1][1];

			$diffs[$pointer][1] = mb_substr($diffs[$pointer][1], mb_strlen($diffs[$pointer +1][1])) . $diffs[$pointer +1][1];
			array_splice($diffs, $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.<Array.<number\|string>>} diffs Array of diff tuples.
			* @param {number} loc Location within text1.
			* @return {number} Location within text2.
			*/
			function diff_xIndex($diffs, $loc) {
			$chars1 = 0;
			$chars2 = 0;
			$last_chars1 = 0;
			$last_chars2 = 0;
			for ($x = 0; $x < count($diffs); $x++) {
			if ($diffs[$x][0] !== DIFF_INSERT) { // Equality or deletion.
			$chars1 += mb_strlen($diffs[$x][1]);
			}
			if ($diffs[$x][0] !== DIFF_DELETE) { // Equality or insertion.
			$chars2 += mb_strlen($diffs[$x][1]);
			}
			if ($chars1 > $loc) { // Overshot the location.
			break;
			}
			$last_chars1 = $chars1;
			$last_chars2 = $chars2;
			}
			// Was the location was deleted?
			if (count($diffs) != $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.<Array.<number\|string>>} diffs Array of diff tuples.
			* @return {string} HTML representation.
			*/
			function diff_prettyHtml($diffs) {
			$html = array ();
			$i = 0;
			for ($x = 0; $x < count($diffs); $x++) {
			$op = $diffs[$x][0]; // Operation (insert, delete, equal)
			$data = $diffs[$x][1]; // Text of change.
			$text = preg_replace(array (
			'/&/',
			'/</',
			'/>/',
			"/\n/"
			), array (
			'&',
			'<',
			'>',
			'¶<BR>'
			), $data);

			switch ($op) {
			case DIFF_INSERT :
			$html[$x] = '<INS STYLE="background:#E6FFE6;" TITLE="i=' . $i . '">' . $text . '</INS>';
			break;
			case DIFF_DELETE :
			$html[$x] = '<DEL STYLE="background:#FFE6E6;" TITLE="i=' . $i . '">' . $text . '</DEL>';
			break;
			case DIFF_EQUAL :
			$html[$x] = '<SPAN TITLE="i=' . $i . '">' . $text . '</SPAN>';
			break;
			}
			if ($op !== DIFF_DELETE) {
			$i += mb_strlen($data);
			}
			}
			return implode('',$html);
			}

			/**
			* Compute and return the source text (all equalities and deletions).
			* @param {Array.<Array.<number\|string>>} diffs Array of diff tuples.
			* @return {string} Source text.
			*/
			function diff_text1($diffs) {
			$text = array ();
			for ($x = 0; $x < count($diffs); $x++) {
			if ($diffs[$x][0] !== DIFF_INSERT) {
			$text[$x] = $diffs[$x][1];
			}
			}
			return implode('',$text);
			}

			/**
			* Compute and return the destination text (all equalities and insertions).
			* @param {Array.<Array.<number\|string>>} diffs Array of diff tuples.
			* @return {string} Destination text.
			*/
			function diff_text2($diffs) {
			$text = array ();
			for ($x = 0; $x < count($diffs); $x++) {
			if ($diffs[$x][0] !== DIFF_DELETE) {
			$text[$x] = $diffs[$x][1];
			}
			}
			return implode('',$text);
			}

			/**
			* Compute the Levenshtein distance; the number of inserted, deleted or
			* substituted characters.
			* @param {Array.<Array.<number\|string>>} diffs Array of diff tuples.
			* @return {number} Number of changes.
			*/
			function diff_levenshtein($diffs) {
			$levenshtein = 0;
			$insertions = 0;
			$deletions = 0;
			for ($x = 0; $x < count($diffs); $x++) {
			$op = $diffs[$x][0];
			$data = $diffs[$x][1];
			switch ($op) {
			case DIFF_INSERT :
			$insertions += mb_strlen($data);
			break;
			case DIFF_DELETE :
			$deletions += mb_strlen($data);
			break;
			case DIFF_EQUAL :
			// A deletion and an insertion is one substitution.
			$levenshtein += max($insertions, $deletions);
			$insertions = 0;
			$deletions = 0;
			break;
			}
			}
			$levenshtein += max($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.<Array.<number\|string>>} diffs Array of diff tuples.
			* @return {string} Delta text.
			*/
			function diff_toDelta($diffs) {
			$text = array ();
			for ($x = 0; $x < count($diffs); $x++) {
			switch ($diffs[$x][0]) {
			case DIFF_INSERT :
			$text[$x] = '+' .encodeURI($diffs[$x][1]);
			break;
			case DIFF_DELETE :
			$text[$x] = '-' .mb_strlen($diffs[$x][1]);
			break;
			case DIFF_EQUAL :
			$text[$x] = '=' .mb_strlen($diffs[$x][1]);
			break;
			}
			}
			return str_replace('%20', ' ', implode("\t", $text));
			}

			/**
			* 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.<Array.<number\|string>>} Array of diff tuples.
			* @throws {Error} If invalid input.
			*/
			function diff_fromDelta($text1, $delta) {
			$diffs = array ();
			$diffsLength = 0; // Keeping our own length var is faster in JS.
			$pointer = 0; // Cursor in text1
			$tokens = preg_split("/\t/", $delta);

			for ($x = 0; $x < count($tokens); $x++) {
			// Each token begins with a one character parameter which specifies the
			// operation of this token (delete, insert, equality).
			$param = mb_substr($tokens[$x], 1);
			switch ($tokens[$x][0]) {
			case '+' :
			try {
			$diffs[$diffsLength++] = array (
			DIFF_INSERT,
			decodeURI($param)
			);
			} catch (Exception $ex) {
			echo_Exception('Illegal escape in diff_fromDelta: ' . $param);
			// Malformed URI sequence.
			}
			break;
			case '-' :
			// Fall through.
			case '=' :
			$n = (int) $param;
			if ($n < 0) {
			echo_Exception('Invalid number in diff_fromDelta: ' . $param);
			}
			$text = mb_substr($text1, $pointer, $n);
			$pointer += $n;
			if ($tokens[$x][0] == '=') {
			$diffs[$diffsLength++] = array (
			DIFF_EQUAL,
			$text
			);
			} else {
			$diffs[$diffsLength++] = array (
			DIFF_DELETE,
			$text
			);
			}
			break;
			default :
			// Blank tokens are ok (from a trailing \t).
			// Anything else is an error.
			if ($tokens[$x]) {
			echo_Exception('Invalid diff operation in diff_fromDelta: ' . $tokens[$x]);
			}
			}
			}
			if ($pointer != mb_strlen($text1)) {
			// throw new Exception('Delta length (' . $pointer . ') does not equal source text length (' . mb_strlen($text1) . ').');
			echo_Exception('Delta length (' . $pointer . ') does not equal source text length (' . mb_strlen($text1) . ').');
			}
			return $diffs;
			}

			// MATCH FUNCTIONS

			/**
			* Locate the best instance of 'pattern' in 'text' near 'loc'.
			* @param {string} text The text to search.
			* @param {string} pattern The pattern to search for.
			* @param {number} loc The location to search around.
			* @return {number} Best match index or -1.
			*/
			function match_main($text, $pattern, $loc) {
			$loc = max(0, min($loc, mb_strlen($text)));
			if ($text == $pattern) {
			// Shortcut (potentially not guaranteed by the algorithm)
			return 0;
			}
			elseif (!mb_strlen($text)) {
			// Nothing to match.
			return -1;
			}
			elseif (mb_substr($text, $loc, mb_strlen($pattern)) == $pattern) {
			// Perfect match at the perfect spot! (Includes case of null pattern)
			return $loc;
			} else {
			// Do a fuzzy compare.
			return $this->match_bitap($text, $pattern, $loc);
			}
			}

			/**
			* Locate the best instance of 'pattern' in 'text' near 'loc' using the
			* Bitap algorithm.
			* @param {string} text The text to search.
			* @param {string} pattern The pattern to search for.
			* @param {number} loc The location to search around.
			* @return {number} Best match index or -1.
			* @private
			*/
			function match_bitap($text, $pattern, $loc) {
			if (mb_strlen($pattern) > Match_MaxBits) {
			echo_Exception('Pattern too long for this browser.');
			}

			// Initialise the alphabet.
			$s = $this->match_alphabet($pattern);

			// Highest score beyond which we give up.
			$score_threshold = $this->Match_Threshold;

			// Is there a nearby exact match? (speedup)
			$best_loc = mb_strpos($text, $pattern, $loc);
			if ($best_loc !== false) {
			$score_threshold = min($this->match_bitapScore(0, $best_loc, $pattern, $loc), $score_threshold);
			}

			// What about in the other direction? (speedup)
			$best_loc = mb_strrpos( $text, $pattern, min($loc + mb_strlen($pattern), mb_strlen($text)) );
			if ($best_loc !== false) {
			$score_threshold = min($this->match_bitapScore(0, $best_loc, $pattern, $loc), $score_threshold);
			}

			// Initialise the bit arrays.
			$matchmask = 1 << (mb_strlen($pattern) - 1);
			$best_loc = -1;

			$bin_min = null;
			$bin_mid = null;
			$bin_max = mb_strlen($pattern) + mb_strlen($text);
			$last_rd = null;
			for ($d = 0; $d < mb_strlen($pattern); $d++) {
			// Scan for the best match; each iteration allows for one more error.
			// Run a binary search to determine how far from 'loc' we can stray at this
			// error level.
			$bin_min = 0;
			$bin_mid = $bin_max;
			while ($bin_min < $bin_mid) {
			if ($this->match_bitapScore($d, $loc + $bin_mid, $pattern, $loc) <= $score_threshold) {
			$bin_min = $bin_mid;
			} else {
			$bin_max = $bin_mid;
			}
			$bin_mid = floor(($bin_max - $bin_min) / 2 + $bin_min);
			}
			// Use the result from this iteration as the maximum for the next.
			$bin_max = $bin_mid;
			$start = max(1, $loc - $bin_mid +1);
			$finish = min($loc + $bin_mid, mb_strlen($text)) + mb_strlen($pattern);

			$rd = Array (
			$finish +2
			);
			$rd[$finish +1] = (1 << $d) - 1;
			for ($j = $finish; $j >= $start; $j--) {
			// The alphabet (s) is a sparse hash, so the following line generates
			// warnings.
			@ $charMatch = $s[ $text[$j -1] ];
			if ($d === 0) { // First pass: exact match.
			$rd[$j] = (($rd[$j +1] << 1) \| 1) & $charMatch;
			} else { // Subsequent passes: fuzzy match.
			$rd[$j] = (($rd[$j +1] << 1) \| 1) & $charMatch \| ((($last_rd[$j +1] \| $last_rd[$j]) << 1) \| 1) \| $last_rd[$j +1];
			}
			if ($rd[$j] & $matchmask) {
			$score = $this->match_bitapScore($d, $j -1, $pattern, $loc);
			// This match will almost certainly be better than any existing match.
			// But check anyway.
			if ($score <= $score_threshold) {
			// Told you so.
			$score_threshold = $score;
			$best_loc = $j -1;
			if ($best_loc > $loc) {
			// When passing loc, don't exceed our current distance from loc.
			$start = max(1, 2 * $loc - $best_loc);
			} else {
			// Already passed loc, downhill from here on in.
			break;
			}
			}
			}
			}
			// No hope for a (better) match at greater error levels.
			if ($this->match_bitapScore($d +1, $loc, $pattern, $loc) > $score_threshold) {
			break;
			}
			$last_rd = $rd;
			}
			return (int)$best_loc;
			}

			/**
			* Compute and return the score for a match with e errors and x location.
			* Accesses loc and pattern through being a closure.
			* @param {number} e Number of errors in match.
			* @param {number} x Location of match.
			* @return {number} Overall score for match (0.0 = good, 1.0 = bad).
			* @private
			*/
			function match_bitapScore($e, $x, $pattern, $loc) {
			$accuracy = $e / mb_strlen($pattern);
			$proximity = abs($loc - $x);
			if (!$this->Match_Distance) {
			// Dodge divide by zero error.
			return $proximity ? 1.0 : $accuracy;
			}
			return $accuracy + ($proximity / $this->Match_Distance);
			}

			/**
			* Initialise the alphabet for the Bitap algorithm.
			* @param {string} pattern The text to encode.
			* @return {Object} Hash of character locations.
			* @private
			*/
			function match_alphabet($pattern) {
			$s = array ();
			for ($i = 0; $i < mb_strlen($pattern); $i++) {
			$s[ $pattern[$i] ] = 0;
			}
			for ($i = 0; $i < mb_strlen($pattern); $i++) {
			$s[ $pattern[$i] ] \|= 1 << (mb_strlen($pattern) - $i - 1);
			}
			return $s;
			}

			// PATCH FUNCTIONS

			/**
			* Increase the context until it is unique,
			* but don't let the pattern expand beyond Match_MaxBits.
			* @param {patch_obj} patch The patch to grow.
			* @param {string} text Source text.
			* @private
			*/
			function patch_addContext($patch, $text) {
			$pattern = mb_substr($text, $patch->start2, $patch->length1 );
			$previousPattern = null;
			$padding = 0;
			$i = 0;
			while (
			( mb_strlen($pattern) === 0 // Javascript's indexOf/lastIndexOd return 0/strlen respectively if pattern = ''
			\|\| mb_strpos($text, $pattern) !== mb_strrpos($text, $pattern)
			)
			&& $pattern !== $previousPattern // avoid infinte loop
			&& mb_strlen($pattern) < Match_MaxBits - $this->Patch_Margin - $this->Patch_Margin ) {
			$padding += $this->Patch_Margin;
			$previousPattern = $pattern;
			$pattern = mb_substr($text, max($patch->start2 - $padding,0), ($patch->start2 + $patch->length1 + $padding) - max($patch->start2 - $padding,0) );
			}
			// Add one chunk for good luck.
			$padding += $this->Patch_Margin;
			// Add the prefix.
			$prefix = mb_substr($text, max($patch->start2 - $padding,0), $patch->start2 - max($patch->start2 - $padding,0) );
			if ($prefix!=='') {
			array_unshift($patch->diffs, array (
			DIFF_EQUAL,
			$prefix
			));
			}
			// Add the suffix.
			$suffix = mb_substr($text, $patch->start2 + $patch->length1, ($patch->start2 + $patch->length1 + $padding) - ($patch->start2 + $patch->length1) );
			if ($suffix!=='') {
			array_push($patch->diffs, array (
			DIFF_EQUAL,
			$suffix
			));
			}

			// Roll back the start points.
			$patch->start1 -= mb_strlen($prefix);
			$patch->start2 -= mb_strlen($prefix);
			// Extend the lengths.
			$patch->length1 += mb_strlen($prefix) + mb_strlen($suffix);
			$patch->length2 += mb_strlen($prefix) + mb_strlen($suffix);
			}

			/**
			* Compute a list of patches to turn text1 into text2.
			* Use diffs if provided, otherwise compute it ourselves.
			* There are four ways to call this function, depending on what data is
			* available to the caller:
			* Method 1:
			* a = text1, b = text2
			* Method 2:
			* a = diffs
			* Method 3 (optimal):
			* a = text1, b = diffs
			* Method 4 (deprecated, use method 3):
			* a = text1, b = text2, c = diffs
			*
			* @param {string\|Array.<Array.<number\|string>>} a text1 (methods 1,3,4) or
			* Array of diff tuples for text1 to text2 (method 2).
			* @param {string\|Array.<Array.<number\|string>>} opt_b text2 (methods 1,4) or
			* Array of diff tuples for text1 to text2 (method 3) or undefined (method 2).
			* @param {string\|Array.<Array.<number\|string>>} opt_c Array of diff tuples for
			* text1 to text2 (method 4) or undefined (methods 1,2,3).
			* @return {Array.<patch_obj>} Array of patch objects.
			*/
			function patch_make($a, $opt_b = null, $opt_c = null ) {
			if (is_string($a) && is_string($opt_b) && $opt_c === null ) {
			// Method 1: text1, text2
			// Compute diffs from text1 and text2.
			$text1 = $a;
			$diffs = $this->diff_main($text1, $opt_b, true);
			if ( count($diffs) > 2) {
			$this->diff_cleanupSemantic($diffs);
			$this->diff_cleanupEfficiency($diffs);
			}
			} elseif ( is_array($a) && $opt_b === null && $opt_c === null) {
			// Method 2: diffs
			// Compute text1 from diffs.
			$diffs = $a;
			$text1 = $this->diff_text1($diffs);
			} elseif ( is_string($a) && is_array($opt_b) && $opt_c === null) {
			// Method 3: text1, diffs
			$text1 = $a;
			$diffs = $opt_b;
			} elseif ( is_string($a) && is_string($opt_b) && is_array($opt_c) ) {
			// Method 4: text1, text2, diffs
			// text2 is not used.
			$text1 = $a;
			$diffs = $opt_c;
			} else {
			echo_Exception('Unknown call format to patch_make.');
			}

			if ( count($diffs) === 0) {
			return array(); // Get rid of the null case.
			}
			$patches = array();
			$patch = new patch_obj();
			$patchDiffLength = 0; // Keeping our own length var is faster in JS.
			$char_count1 = 0; // Number of characters into the text1 string.
			$char_count2 = 0; // Number of characters into the text2 string.
			// Start with text1 (prepatch_text) and apply the diffs until we arrive at
			// text2 (postpatch_text). We recreate the patches one by one to determine
			// context info.
			$prepatch_text = $text1;
			$postpatch_text = $text1;
			for ($x = 0; $x < count($diffs); $x++) {
			$diff_type = $diffs[$x][0];
			$diff_text = $diffs[$x][1];

			if (!$patchDiffLength && $diff_type !== DIFF_EQUAL) {
			// A new patch starts here.
			$patch->start1 = $char_count1;
			$patch->start2 = $char_count2;
			}

			switch ($diff_type) {
			case DIFF_INSERT :
			$patch->diffs[$patchDiffLength++] = $diffs[$x];
			$patch->length2 += mb_strlen($diff_text);
			$postpatch_text = mb_substr($postpatch_text, 0, $char_count2) . $diff_text . mb_substr($postpatch_text,$char_count2);
			break;
			case DIFF_DELETE :
			$patch->length1 += mb_strlen($diff_text);
			$patch->diffs[$patchDiffLength++] = $diffs[$x];
			$postpatch_text = mb_substr($postpatch_text, 0, $char_count2) . mb_substr($postpatch_text, $char_count2 + mb_strlen($diff_text) );
			break;
			case DIFF_EQUAL :
			if ( mb_strlen($diff_text) <= 2 * $this->Patch_Margin && $patchDiffLength && count($diffs) != $x + 1) {
			// Small equality inside a patch.
			$patch->diffs[$patchDiffLength++] = $diffs[$x];
			$patch->length1 += mb_strlen($diff_text);
			$patch->length2 += mb_strlen($diff_text);
			} elseif ( mb_strlen($diff_text) >= 2 * $this->Patch_Margin ) {
			// Time for a new patch.
			if ($patchDiffLength) {
			$this->patch_addContext($patch, $prepatch_text);
			array_push($patches,$patch);
			$patch = new patch_obj();
			$patchDiffLength = 0;
			// Unlike Unidiff, our patch lists have a rolling context.
			// http://code.google.com/p/google-diff-match-patch/wiki/Unidiff
			// Update prepatch text & pos to reflect the application of the
			// just completed patch.
			$prepatch_text = $postpatch_text;
			$char_count1 = $char_count2;
			}
			}
			break;
			}

			// Update the current character count.
			if ($diff_type !== DIFF_INSERT) {
			$char_count1 += mb_strlen($diff_text);
			}
			if ($diff_type !== DIFF_DELETE) {
			$char_count2 += mb_strlen($diff_text);
			}
			}
			// Pick up the leftover patch if not empty.
			if ($patchDiffLength) {
			$this->patch_addContext($patch, $prepatch_text);
			array_push($patches, $patch);
			}

			return $patches;
			}

			/**
			* Given an array of patches, return another array that is identical.
			* @param {Array.<patch_obj>} patches Array of patch objects.
			* @return {Array.<patch_obj>} Array of patch objects.
			*/
			function patch_deepCopy($patches) {
			// Making deep copies is hard in JavaScript.
			$patchesCopy = array();
			for ($x = 0; $x < count($patches); $x++) {
			$patch = $patches[$x];
			$patchCopy = new patch_obj();
			for ($y = 0; $y < count($patch->diffs); $y++) {
			$patchCopy->diffs[$y] = $patch->diffs[$y]; // ?? . slice();
			}
			$patchCopy->start1 = $patch->start1;
			$patchCopy->start2 = $patch->start2;
			$patchCopy->length1 = $patch->length1;
			$patchCopy->length2 = $patch->length2;
			$patchesCopy[$x] = $patchCopy;
			}
			return $patchesCopy;
			}

			/**
			* Merge a set of patches onto the text. Return a patched text, as well
			* as a list of true/false values indicating which patches were applied.
			* @param {Array.<patch_obj>} patches Array of patch objects.
			* @param {string} text Old text.
			* @return {Array.<string\|Array.<boolean>>} Two element Array, containing the
			* new text and an array of boolean values.
			*/
			function patch_apply($patches, $text) {
			if ( count($patches) == 0) {
			return array($text,array());
			}

			// Deep copy the patches so that no changes are made to originals.
			$patches = $this->patch_deepCopy($patches);

			$nullPadding = $this->patch_addPadding($patches);
			$text = $nullPadding . $text . $nullPadding;

			$this->patch_splitMax($patches);
			// delta keeps track of the offset between the expected and actual location
			// of the previous patch. If there are patches expected at positions 10 and
			// 20, but the first patch was found at 12, delta is 2 and the second patch
			// has an effective expected position of 22.
			$delta = 0;
			$results = array();
			for ($x = 0; $x < count($patches) ; $x++) {
			$expected_loc = $patches[$x]->start2 + $delta;
			$text1 = $this->diff_text1($patches[$x]->diffs);
			$start_loc = null;
			$end_loc = -1;
			if (mb_strlen($text1) > Match_MaxBits) {
			// patch_splitMax will only provide an oversized pattern in the case of
			// a monster delete.
			$start_loc = $this->match_main($text, mb_substr($text1, 0, Match_MaxBits ), $expected_loc);
			if ($start_loc != -1) {
			$end_loc = $this->match_main($text, mb_substr($text1,mb_strlen($text1) - Match_MaxBits), $expected_loc + mb_strlen($text1) - Match_MaxBits);
			if ($end_loc == -1 \|\| $start_loc >= $end_loc) {
			// Can't find valid trailing context. Drop this patch.
			$start_loc = -1;
			}
			}
			} else {
			$start_loc = $this->match_main($text, $text1, $expected_loc);
			}
			if ($start_loc == -1) {
			// No match found. :(
			$results[$x] = false;
			// Subtract the delta for this failed patch from subsequent patches.
			$delta -= $patches[$x]->length2 - $patches[$x]->length1;
			} else {
			// Found a match. :)
			$results[$x] = true;
			$delta = $start_loc - $expected_loc;
			$text2 = null;
			if ($end_loc == -1) {
			$text2 = mb_substr($text, $start_loc, mb_strlen($text1) );
			} else {
			$text2 = mb_substr($text, $start_loc, $end_loc + Match_MaxBits - $start_loc);
			}
			if ($text1 == $text2) {
			// Perfect match, just shove the replacement text in.
			$text = mb_substr($text, 0, $start_loc) . $this->diff_text2($patches[$x]->diffs) . mb_substr($text,$start_loc + mb_strlen($text1) );
			} else {
			// Imperfect match. Run a diff to get a framework of equivalent
			// indices.
			$diffs = $this->diff_main($text1, $text2, false);
			if ( mb_strlen($text1) > Match_MaxBits && $this->diff_levenshtein($diffs) / mb_strlen($text1) > $this->Patch_DeleteThreshold) {
			// The end points match, but the content is unacceptably bad.
			$results[$x] = false;
			} else {
			$this->diff_cleanupSemanticLossless($diffs);
			$index1 = 0;
			$index2 = NULL;
			for ($y = 0; $y < count($patches[$x]->diffs); $y++) {
			$mod = $patches[$x]->diffs[$y];
			if ($mod[0] !== DIFF_EQUAL) {
			$index2 = $this->diff_xIndex($diffs, $index1);
			}
			if ($mod[0] === DIFF_INSERT) { // Insertion
			$text = mb_substr($text, 0, $start_loc + $index2) . $mod[1] . mb_substr($text, $start_loc + $index2);
			} elseif ($mod[0] === DIFF_DELETE) { // Deletion
			$text = mb_substr($text, 0, $start_loc + $index2) . mb_substr($text,$start_loc + $this->diff_xIndex($diffs, $index1 + mb_strlen($mod[1]) ));
			}
			if ($mod[0] !== DIFF_DELETE) {
			$index1 += mb_strlen($mod[1]);
			}
			}
			}
			}
			}
			}
			// Strip the padding off.
			$text = mb_substr($text, mb_strlen($nullPadding), mb_strlen($text) - 2*mb_strlen($nullPadding) );
			return array($text, $results);
			}

			/**
			* Add some padding on text start and end so that edges can match something.
			* Intended to be called only from within patch_apply.
			* @param {Array.<patch_obj>} patches Array of patch objects.
			* @return {string} The padding string added to each side.
			*/
			function patch_addPadding(&$patches){
			$paddingLength = $this->Patch_Margin;
			$nullPadding = '';
			for ($x = 1; $x <= $paddingLength; $x++) {
			$nullPadding .= mb_chr($x);
			}

			// Bump all the patches forward.
			for ($x = 0; $x < count($patches); $x++) {
			$patches[$x]->start1 += $paddingLength;
			$patches[$x]->start2 += $paddingLength;
			}

			// Add some padding on start of first diff.
			$patch = &$patches[0];
			$diffs = &$patch->diffs;
			if (count($diffs) == 0 \|\| $diffs[0][0] != DIFF_EQUAL) {
			// Add nullPadding equality.
			array_unshift($diffs, array(DIFF_EQUAL, $nullPadding));
			$patch->start1 -= $paddingLength; // Should be 0.
			$patch->start2 -= $paddingLength; // Should be 0.
			$patch->length1 += $paddingLength;
			$patch->length2 += $paddingLength;
			} elseif ($paddingLength > mb_strlen($diffs[0][1]) ) {
			// Grow first equality.
			$extraLength = $paddingLength - mb_strlen($diffs[0][1]);
			$diffs[0][1] = mb_substr( $nullPadding , mb_strlen($diffs[0][1]) ) . $diffs[0][1];
			$patch->start1 -= $extraLength;
			$patch->start2 -= $extraLength;
			$patch->length1 += $extraLength;
			$patch->length2 += $extraLength;
			}

			// Add some padding on end of last diff.
			$patch = &$patches[count($patches) - 1];
			$diffs = &$patch->diffs;
			if ( count($diffs) == 0 \|\| $diffs[ count($diffs) - 1][0] != DIFF_EQUAL) {
			// Add nullPadding equality.
			array_push($diffs, array(DIFF_EQUAL, $nullPadding) );
			$patch->length1 += $paddingLength;
			$patch->length2 += $paddingLength;
			} elseif ($paddingLength > mb_strlen( $diffs[count($diffs)-1][1] ) ) {
			// Grow last equality.
			$extraLength = $paddingLength - mb_strlen( $diffs[count($diffs)-1][1] );
			$diffs[ count($diffs)-1][1] .= mb_substr($nullPadding,0,$extraLength);
			$patch->length1 += $extraLength;
			$patch->length2 += $extraLength;
			}

			return $nullPadding;
			}

			/**
			* Look through the patches and break up any which are longer than the maximum
			* limit of the match algorithm.
			* @param {Array.<patch_obj>} patches Array of patch objects.
			*/
			function patch_splitMax(&$patches) {
			for ($x = 0; $x < count($patches); $x++) {
			if ( $patches[$x]->length1 > Match_MaxBits) {
			$bigpatch = $patches[$x];
			// Remove the big old patch.
			array_splice($patches,$x--,1);
			$patch_size = Match_MaxBits;
			$start1 = $bigpatch->start1;
			$start2 = $bigpatch->start2;
			$precontext = '';
			while ( count($bigpatch->diffs) !== 0) {
			// Create one of several smaller patches.
			$patch = new patch_obj();
			$empty = true;
			$patch->start1 = $start1 - mb_strlen($precontext);
			$patch->start2 = $start2 - mb_strlen($precontext);
			if ($precontext !== '') {
			$patch->length1 = $patch->length2 = mb_strlen($precontext);
			array_push($patch->diffs, array(DIFF_EQUAL, $precontext) );
			}
			while ( count($bigpatch->diffs) !== 0 && $patch->length1 < $patch_size - $this->Patch_Margin) {
			$diff_type = $bigpatch->diffs[0][0];
			$diff_text = $bigpatch->diffs[0][1];
			if ($diff_type === DIFF_INSERT) {
			// Insertions are harmless.
			$patch->length2 += mb_strlen($diff_text);
			$start2 += mb_strlen($diff_text);
			array_push($patch->diffs, array_shift($bigpatch->diffs) );
			$empty = false;
			} else
			if ($diff_type === DIFF_DELETE && count($patch->diffs) == 1 && $patch->diffs[0][0] == DIFF_EQUAL && (mb_strlen($diff_text) > 2 * $patch_size) ) {
			// This is a large deletion. Let it pass in one chunk.
			$patch->length1 += mb_strlen($diff_text);
			$start1 += mb_strlen($diff_text);
			$empty = false;
			array_push( $patch->diffs, array($diff_type, $diff_text) );
			array_shift($bigpatch->diffs);
			} else {
			// Deletion or equality. Only take as much as we can stomach.
			$diff_text = mb_substr($diff_text, 0, $patch_size - $patch->length1 - $this->Patch_Margin);
			$patch->length1 += mb_strlen($diff_text);
			$start1 += mb_strlen($diff_text);
			if ($diff_type === DIFF_EQUAL) {
			$patch->length2 += mb_strlen($diff_text);
			$start2 += mb_strlen($diff_text);
			} else {
			$empty = false;
			}
			array_push($patch->diffs, array($diff_type, $diff_text) );
			if ($diff_text == $bigpatch->diffs[0][1]) {
			array_shift($bigpatch->diffs);
			} else {
			$bigpatch->diffs[0][1] = mb_substr( $bigpatch->diffs[0][1],mb_strlen($diff_text) );
			}
			}
			}
			// Compute the head context for the next patch.
			$precontext = $this->diff_text2($patch->diffs);
			$precontext = mb_substr($precontext, mb_strlen($precontext)-$this->Patch_Margin);
			// Append the end context for this patch.
			$postcontext = mb_substr( $this->diff_text1($bigpatch->diffs), 0, $this->Patch_Margin );
			if ($postcontext !== '') {
			$patch->length1 += mb_strlen($postcontext);
			$patch->length2 += mb_strlen($postcontext);
			if ( count($patch->diffs) !== 0 && $patch->diffs[ count($patch->diffs) - 1][0] === DIFF_EQUAL) {
			$patch->diffs[ count($patch->diffs) - 1][1] .= $postcontext;
			} else {
			array_push($patch->diffs, array(DIFF_EQUAL, $postcontext));
			}
			}
			if (!$empty) {
			array_splice($patches, ++$x, 0, array($patch));
			}
			}
			}
			}
			}

			/**
			* Take a list of patches and return a textual representation.
			* @param {Array.<patch_obj>} patches Array of patch objects.
			* @return {string} Text representation of patches.
			*/
			function patch_toText($patches) {
			$text = array();
			for ($x = 0; $x < count($patches) ; $x++) {
			$text[$x] = $patches[$x];
			}
			return implode('',$text);
			}

			/**
			* Parse a textual representation of patches and return a list of patch objects.
			* @param {string} textline Text representation of patches.
			* @return {Array.<patch_obj>} Array of patch objects.
			* @throws {Error} If invalid input.
			*/
			function patch_fromText($textline) {
			$patches = array();
			if ($textline === '') {
			return $patches;
			}
			$text = explode("\n",$textline);
			foreach($text as $i=>$t){ if($t===''){ unset($text[$i]); } }
			$textPointer = 0;
			while ($textPointer < count($text) ) {
			$m = null;
			preg_match('/^@@ -(\d+),?(\d) \+(\d+),?(\d) @@$/',$text[$textPointer],$m);
			if (!$m) {
			echo_Exception('Invalid patch string: ' . $text[$textPointer]);
			}
			$patch = new patch_obj();
			array_push($patches, $patch);
			@$patch->start1 = (int)$m[1];
			if (@$m[2] === '') {
			$patch->start1--;
			$patch->length1 = 1;
			} elseif ( @$m[2] == '0') {
			$patch->length1 = 0;
			} else {
			$patch->start1--;
			@$patch->length1 = (int)$m[2];
			}

			@$patch->start2 = (int)$m[3];
			if (@$m[4] === '') {
			$patch->start2--;
			$patch->length2 = 1;
			} elseif ( @$m[4] == '0') {
			$patch->length2 = 0;
			} else {
			$patch->start2--;
			@$patch->length2 = (int)$m[4];
			}
			$textPointer++;

			while ($textPointer < count($text) ) {
			$sign = $text[$textPointer][0];
			try {
			$line = decodeURI( mb_substr($text[$textPointer],1) );
			} catch (Exception $ex) {
			// Malformed URI sequence.
			throw new Exception('Illegal escape in patch_fromText: ' . $line);
			}
			if ($sign == '-') {
			// Deletion.
			array_push( $patch->diffs, array(DIFF_DELETE, $line) );
			} elseif ($sign == '+') {
			// Insertion.
			array_push($patch->diffs, array(DIFF_INSERT, $line) );
			} elseif ($sign == ' ') {
			// Minor equality.
			array_push($patch->diffs, array(DIFF_EQUAL, $line) );
			} elseif ($sign == '@') {
			// Start of next patch.
			break;
			} elseif ($sign === '') {
			// Blank line? Whatever.
			} else {
			// WTF?
			echo_Exception('Invalid patch mode "' . $sign . '" in: ' . $line);
			}
			$textPointer++;
			}
			}
			return $patches;
			}
			}

			/**
			* Class representing one patch operation.
			* @constructor
			*/
			class patch_obj {
			/** @type {Array.<Array.<number\|string>>} */
			public $diffs = array();
			/** @type {number?} */
			public $start1 = null;
			/** @type {number?} */
			public $start2 = null;
			/** @type {number} */
			public $length1 = 0;
			/** @type {number} */
			public $length2 = 0;

			/**
			* Emmulate GNU diff's format.
			* Header: @@ -382,8 +481,9 @@
			* Indicies are printed as 1-based, not 0-based.
			* @return {string} The GNU diff string.
			*/
			function toString() {
			if ($this->length1 === 0) {
			$coords1 = $this->start1 . ',0';
			} elseif ($this->length1 == 1) {
			$coords1 = $this->start1 + 1;
			} else {
			$coords1 = ($this->start1 + 1) . ',' . $this->length1;
			}
			if ($this->length2 === 0) {
			$coords2 = $this->start2 . ',0';
			} elseif ($this->length2 == 1) {
			$coords2 = $this->start2 + 1;
			} else {
			$coords2 = ($this->start2 + 1) . ',' . $this->length2;
			}
			$text = array ( '@@ -' . $coords1 . ' +' . $coords2 . " @@\n" );

			// Escape the body of the patch with %xx notation.
			for ($x = 0; $x < count($this->diffs); $x++) {
			switch ($this->diffs[$x][0]) {
			case DIFF_INSERT :
			$op = '+';
			break;
			case DIFF_DELETE :
			$op = '-';
			break;
			case DIFF_EQUAL :
			$op = ' ';
			break;
			}
			$text[$x +1] = $op . encodeURI($this->diffs[$x][1]) . "\n";
			}
			return str_replace('%20', ' ', implode('',$text));
			}
			function __toString(){
			return $this->toString();
			}
			}

			define('DIFF_DELETE', -1);
			define('DIFF_INSERT', 1);
			define('DIFF_EQUAL', 0);

			define('Match_MaxBits', PHP_INT_SIZE * 8);


			function charCodeAt($str, $pos) {
			return mb_ord(mb_substr($str, $pos, 1));
			}
			function mb_ord($v) {
			$k = mb_convert_encoding($v, 'UCS-2LE', 'UTF-8');
			$k1 = ord(substr($k, 0, 1));
			$k2 = ord(substr($k, 1, 1));
			return $k2 * 256 + $k1;
			}
			function mb_chr($num){
			return mb_convert_encoding('&#'.intval($num).';', 'UTF-8', 'HTML-ENTITIES');
			}

			/**
			* as in javascript encodeURI() following the MDN description
			*
			* @link https://developer.mozilla.org/en/JavaScript/Reference/Global_Objects/encodeURI
			* @param $url
			* @return string
			*/
			function encodeURI($url) {
			return strtr(rawurlencode($url), array (
			'%3B' => ';', '%2C' => ',', '%2F' => '/', '%3F' => '?', '%3A' => ':', '%40' => '@', '%26' => '&', '%3D' => '=',
			'%2B' => '+', '%24' => '$', '%21' => '!', '%2A' => '*', '%27' => '\'', '%28' => '(', '%29' => ')', '%23' => '#',
			));
			}

			function decodeURI($encoded) {
			static $dontDecode;
			if (!$dontDecode) {
			$table = array (
			'%3B' => ';', '%2C' => ',', '%2F' => '/', '%3F' => '?', '%3A' => ':', '%40' => '@', '%26' => '&', '%3D' => '=',
			'%2B' => '+', '%24' => '$', '%21' => '!', '%2A' => '*', '%27' => '\'', '%28' => '(', '%29' => ')', '%23' => '#',
			);
			$dontDecode = array();
			foreach ($table as $k => $v) {
			$dontDecode[$k] = encodeURI($k);
			}
			}
			return rawurldecode(strtr($encoded, $dontDecode));
			}

			function echo_Exception($str){
			global $lastException;
			$lastException = $str;
			echo $str;
			}
			//mb_internal_encoding("UTF-8");

			?>

phab/externals/diff_match_patch/diff_match_patch.php935ced1eddbeproduction

diff_match_patch.phpView Options

phab/externals/diff_match_patch/diff_match_patch.php
935ced1eddbeproduction

diff_match_patch.php
View Options