File Content: SequenceMatcher.php <?php /** * Sequence matcher for Diff * * PHP version 5 * * Copyright (c) 2009 Chris Boulton <chris.boulton@interspire.com> * * All rights reserved. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions are met: * * - Redistributions of source code must retain the above copyright notice, * this list of conditions and the following disclaimer. * - Redistributions in binary form must reproduce the above copyright notice, * this list of conditions and the following disclaimer in the documentation * and/or other materials provided with the distribution. * - Neither the name of the Chris Boulton nor the names of its contributors * may be used to endorse or promote products derived from this software * without specific prior written permission. * * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE * POSSIBILITY OF SUCH DAMAGE. * * @package Diff * @author Chris Boulton <chris.boulton@interspire.com> * @copyright (c) 2009 Chris Boulton * @license New BSD License http://www.opensource.org/licenses/bsd-license.php * @version 1.1 * @link http://github.com/chrisboulton/php-diff */ class WPR_Diff_SequenceMatcher { /** * @var string|array Either a string or an array containing a callback function to determine if a line is "junk" or not. */ private $junkCallback = null; /** * @var array The first sequence to compare against. */ private $a = null; /** * @var array The second sequence. */ private $b = null; /** * @var array Array of characters that are considered junk from the second sequence. Characters are the array key. */ private $junkDict = array(); /** * @var array Array of indices that do not contain junk elements. */ private $b2j = array(); private $options = array(); private $defaultOptions = array( 'ignoreNewLines' => false, 'ignoreWhitespace' => false, 'ignoreCase' => false ); /** * The constructor. With the sequences being passed, they'll be set for the * sequence matcher and it will perform a basic cleanup & calculate junk * elements. * * @param string|array $a A string or array containing the lines to compare against. * @param string|array $b A string or array containing the lines to compare. * @param string|array $junkCallback Either an array or string that references a callback function (if there is one) to determine 'junk' characters. */ public function __construct($a, $b, $junkCallback=null, $options) { $this->a = null; $this->b = null; $this->junkCallback = $junkCallback; $this->setOptions($options); $this->setSequences($a, $b); } public function setOptions($options) { $this->options = array_merge($this->defaultOptions, $options); } /** * Set the first and second sequences to use with the sequence matcher. * * @param string|array $a A string or array containing the lines to compare against. * @param string|array $b A string or array containing the lines to compare. */ public function setSequences($a, $b) { $this->setSeq1($a); $this->setSeq2($b); } /** * Set the first sequence ($a) and reset any internal caches to indicate that * when calling the calculation methods, we need to recalculate them. * * @param string|array $a The sequence to set as the first sequence. */ public function setSeq1($a) { if(!is_array($a)) { $a = str_split($a); } if($a == $this->a) { return; } $this->a= $a; $this->matchingBlocks = null; $this->opCodes = null; } /** * Set the second sequence ($b) and reset any internal caches to indicate that * when calling the calculation methods, we need to recalculate them. * * @param string|array $b The sequence to set as the second sequence. */ public function setSeq2($b) { if(!is_array($b)) { $b = str_split($b); } if($b == $this->b) { return; } $this->b = $b; $this->matchingBlocks = null; $this->opCodes = null; $this->fullBCount = null; $this->chainB(); } /** * Generate the internal arrays containing the list of junk and non-junk * characters for the second ($b) sequence. */ private function chainB() { $length = count ($this->b); $this->b2j = array(); $popularDict = array(); for($i = 0; $i < $length; ++$i) { $char = $this->b[$i]; if(isset($this->b2j[$char])) { if($length >= 200 && count($this->b2j[$char]) * 100 > $length) { $popularDict[$char] = 1; unset($this->b2j[$char]); } else { $this->b2j[$char][] = $i; } } else { $this->b2j[$char] = array( $i ); } } // Remove leftovers foreach(array_keys($popularDict) as $char) { unset($this->b2j[$char]); } $this->junkDict = array(); if(is_callable($this->junkCallback)) { foreach(array_keys($popularDict) as $char) { if(call_user_func($this->junkCallback, $char)) { $this->junkDict[$char] = 1; unset($popularDict[$char]); } } foreach(array_keys($this->b2j) as $char) { if(call_user_func($this->junkCallback, $char)) { $this->junkDict[$char] = 1; unset($this->b2j[$char]); } } } } /** * Checks if a particular character is in the junk dictionary * for the list of junk characters. * * @return boolean $b True if the character is considered junk. False if not. */ private function isBJunk($b) { if(isset($this->juncDict[$b])) { return true; } return false; } /** * Find the longest matching block in the two sequences, as defined by the * lower and upper constraints for each sequence. (for the first sequence, * $alo - $ahi and for the second sequence, $blo - $bhi) * * Essentially, of all of the maximal matching blocks, return the one that * startest earliest in $a, and all of those maximal matching blocks that * start earliest in $a, return the one that starts earliest in $b. * * If the junk callback is defined, do the above but with the restriction * that the junk element appears in the block. Extend it as far as possible * by matching only junk elements in both $a and $b. * * @param int $alo The lower constraint for the first sequence. * @param int $ahi The upper constraint for the first sequence. * @param int $blo The lower constraint for the second sequence. * @param int $bhi The upper constraint for the second sequence. * @return array Array containing the longest match that includes the starting position in $a, start in $b and the length/size. */ public function findLongestMatch($alo, $ahi, $blo, $bhi) { $a = $this->a; $b = $this->b; $bestI = $alo; $bestJ = $blo; $bestSize = 0; $j2Len = array(); $nothing = array(); for($i = $alo; $i < $ahi; ++$i) { $newJ2Len = array(); $jDict = $this->arrayGetDefault($this->b2j, $a[$i], $nothing); foreach($jDict as $jKey => $j) { if($j < $blo) { continue; } else if($j >= $bhi) { break; } $k = $this->arrayGetDefault($j2Len, $j -1, 0) + 1; $newJ2Len[$j] = $k; if($k > $bestSize) { $bestI = $i - $k + 1; $bestJ = $j - $k + 1; $bestSize = $k; } } $j2Len = $newJ2Len; } while($bestI > $alo && $bestJ > $blo && !$this->isBJunk($b[$bestJ - 1]) && !$this->linesAreDifferent($bestI - 1, $bestJ - 1)) { --$bestI; --$bestJ; ++$bestSize; } while($bestI + $bestSize < $ahi && ($bestJ + $bestSize) < $bhi && !$this->isBJunk($b[$bestJ + $bestSize]) && !$this->linesAreDifferent($bestI + $bestSize, $bestJ + $bestSize)) { ++$bestSize; } while($bestI > $alo && $bestJ > $blo && $this->isBJunk($b[$bestJ - 1]) && !$this->isLineDifferent($bestI - 1, $bestJ - 1)) { --$bestI; --$bestJ; ++$bestSize; } while($bestI + $bestSize < $ahi && $bestJ + $bestSize < $bhi && $this->isBJunk($b[$bestJ + $bestSize]) && !$this->linesAreDifferent($bestI + $bestSize, $bestJ + $bestSize)) { ++$bestSize; } return array( $bestI, $bestJ, $bestSize ); } /** * Check if the two lines at the given indexes are different or not. * * @param int $aIndex Line number to check against in a. * @param int $bIndex Line number to check against in b. * @return boolean True if the lines are different and false if not. */ public function linesAreDifferent($aIndex, $bIndex) { $lineA = $this->a[$aIndex]; $lineB = $this->b[$bIndex]; if($this->options['ignoreWhitespace']) { $replace = array("\t", ' '); $lineA = str_replace($replace, '', $lineA); $lineB = str_replace($replace, '', $lineB); } if($this->options['ignoreCase']) { $lineA = strtolower($lineA); $lineB = strtolower($lineB); } if($lineA != $lineB) { return true; } return false; } /** * Return a nested set of arrays for all of the matching sub-sequences * in the strings $a and $b. * * Each block contains the lower constraint of the block in $a, the lower * constraint of the block in $b and finally the number of lines that the * block continues for. * * @return array Nested array of the matching blocks, as described by the function. */ public function getMatchingBlocks() { if(!empty($this->matchingBlocks)) { return $this->matchingBlocks; } $aLength = count($this->a); $bLength = count($this->b); $queue = array( array( 0, $aLength, 0, $bLength ) ); $matchingBlocks = array(); while(!empty($queue)) { list($alo, $ahi, $blo, $bhi) = array_pop($queue); $x = $this->findLongestMatch($alo, $ahi, $blo, $bhi); list($i, $j, $k) = $x; if($k) { $matchingBlocks[] = $x; if($alo < $i && $blo < $j) { $queue[] = array( $alo, $i, $blo, $j ); } if($i + $k < $ahi && $j + $k < $bhi) { $queue[] = array( $i + $k, $ahi, $j + $k, $bhi ); } } } usort($matchingBlocks, array($this, 'tupleSort')); $i1 = 0; $j1 = 0; $k1 = 0; $nonAdjacent = array(); foreach($matchingBlocks as $block) { list($i2, $j2, $k2) = $block; if($i1 + $k1 == $i2 && $j1 + $k1 == $j2) { $k1 += $k2; } else { if($k1) { $nonAdjacent[] = array( $i1, $j1, $k1 ); } $i1 = $i2; $j1 = $j2; $k1 = $k2; } } if($k1) { $nonAdjacent[] = array( $i1, $j1, $k1 ); } $nonAdjacent[] = array( $aLength, $bLength, 0 ); $this->matchingBlocks = $nonAdjacent; return $this->matchingBlocks; } /** * Return a list of all of the opcodes for the differences between the * two strings. * * The nested array returned contains an array describing the opcode * which includes: * 0 - The type of tag (as described below) for the opcode. * 1 - The beginning line in the first sequence. * 2 - The end line in the first sequence. * 3 - The beginning line in the second sequence. * 4 - The end line in the second sequence. * * The different types of tags include: * replace - The string from $i1 to $i2 in $a should be replaced by * the string in $b from $j1 to $j2. * delete - The string in $a from $i1 to $j2 should be deleted. * insert - The string in $b from $j1 to $j2 should be inserted at * $i1 in $a. * equal - The two strings with the specified ranges are equal. * * @return array Array of the opcodes describing the differences between the strings. */ public function getOpCodes() { if(!empty($this->opCodes)) { return $this->opCodes; } $i = 0; $j = 0; $this->opCodes = array(); $blocks = $this->getMatchingBlocks(); foreach($blocks as $block) { list($ai, $bj, $size) = $block; $tag = ''; if($i < $ai && $j < $bj) { $tag = 'replace'; } else if($i < $ai) { $tag = 'delete'; } else if($j < $bj) { $tag = 'insert'; } if($tag) { $this->opCodes[] = array( $tag, $i, $ai, $j, $bj ); } $i = $ai + $size; $j = $bj + $size; if($size) { $this->opCodes[] = array( 'equal', $ai, $i, $bj, $j ); } } return $this->opCodes; } /** * Return a series of nested arrays containing different groups of generated * opcodes for the differences between the strings with up to $context lines * of surrounding content. * * Essentially what happens here is any big equal blocks of strings are stripped * out, the smaller subsets of changes are then arranged in to their groups. * This means that the sequence matcher and diffs do not need to include the full * content of the different files but can still provide context as to where the * changes are. * * @param int $context The number of lines of context to provide around the groups. * @return array Nested array of all of the grouped opcodes. */ public function getGroupedOpcodes($context=3) { $opCodes = $this->getOpCodes(); if(empty($opCodes)) { $opCodes = array( array( 'equal', 0, 1, 0, 1 ) ); } if($opCodes[0][0] == 'equal') { $opCodes[0] = array( $opCodes[0][0], max($opCodes[0][1], $opCodes[0][2] - $context), $opCodes[0][2], max($opCodes[0][3], $opCodes[0][4] - $context), $opCodes[0][4] ); } $lastItem = count($opCodes) - 1; if($opCodes[$lastItem][0] == 'equal') { list($tag, $i1, $i2, $j1, $j2) = $opCodes[$lastItem]; $opCodes[$lastItem] = array( $tag, $i1, min($i2, $i1 + $context), $j1, min($j2, $j1 + $context) ); } $maxRange = $context * 2; $groups = array(); $group = array(); foreach($opCodes as $code) { list($tag, $i1, $i2, $j1, $j2) = $code; if($tag == 'equal' && $i2 - $i1 > $maxRange) { $group[] = array( $tag, $i1, min($i2, $i1 + $context), $j1, min($j2, $j1 + $context) ); $groups[] = $group; $group = array(); $i1 = max($i1, $i2 - $context); $j1 = max($j1, $j2 - $context); } $group[] = array( $tag, $i1, $i2, $j1, $j2 ); } if(!empty($group) && !(count($group) == 1 && $group[0][0] == 'equal')) { $groups[] = $group; } return $groups; } /** * Return a measure of the similarity between the two sequences. * This will be a float value between 0 and 1. * * Out of all of the ratio calculation functions, this is the most * expensive to call if getMatchingBlocks or getOpCodes is yet to be * called. The other calculation methods (quickRatio and realquickRatio) * can be used to perform quicker calculations but may be less accurate. * * The ratio is calculated as (2 * number of matches) / total number of * elements in both sequences. * * @return float The calculated ratio. */ public function Ratio() { $matches = array_reduce($this->getMatchingBlocks(), array($this, 'ratioReduce'), 0); return $this->calculateRatio($matches, count ($this->a) + count ($this->b)); } /** * Helper function to calculate the number of matches for Ratio(). * * @param int $sum The running total for the number of matches. * @param array $triple Array containing the matching block triple to add to the running total. * @return int The new running total for the number of matches. */ private function ratioReduce($sum, $triple) { return $sum + ($triple[count($triple) - 1]); } /** * Quickly return an upper bound ratio for the similarity of the strings. * This is quicker to compute than Ratio(). * * @return float The calculated ratio. */ private function quickRatio() { if($this->fullBCount === null) { $this->fullBCount = array(); $bLength = count ($b); for($i = 0; $i < $bLength; ++$i) { $char = $this->b[$i]; $this->fullBCount[$char] = $this->arrayGetDefault($this->fullBCount, $char, 0) + 1; } } $avail = array(); $matches = 0; $aLength = count ($this->a); for($i = 0; $i < $aLength; ++$i) { $char = $this->a[$i]; if(isset($avail[$char])) { $numb = $avail[$char]; } else { $numb = $this->arrayGetDefault($this->fullBCount, $char, 0); } $avail[$char] = $numb - 1; if($numb > 0) { ++$matches; } } $this->calculateRatio($matches, count ($this->a) + count ($this->b)); } /** * Return an upper bound ratio really quickly for the similarity of the strings. * This is quicker to compute than Ratio() and quickRatio(). * * @return float The calculated ratio. */ private function realquickRatio() { $aLength = count ($this->a); $bLength = count ($this->b); return $this->calculateRatio(min($aLength, $bLength), $aLength + $bLength); } /** * Helper function for calculating the ratio to measure similarity for the strings. * The ratio is defined as being 2 * (number of matches / total length) * * @param int $matches The number of matches in the two strings. * @param int $length The length of the two strings. * @return float The calculated ratio. */ private function calculateRatio($matches, $length=0) { if($length) { return 2 * ($matches / $length); } else { return 1; } } /** * Helper function that provides the ability to return the value for a key * in an array of it exists, or if it doesn't then return a default value. * Essentially cleaner than doing a series of if(isset()) {} else {} calls. * * @param array $array The array to search. * @param string $key The key to check that exists. * @param mixed $default The value to return as the default value if the key doesn't exist. * @return mixed The value from the array if the key exists or otherwise the default. */ private function arrayGetDefault($array, $key, $default) { if(isset($array[$key])) { return $array[$key]; } else { return $default; } } /** * Sort an array by the nested arrays it contains. Helper function for getMatchingBlocks * * @param array $a First array to compare. * @param array $b Second array to compare. * @return int -1, 0 or 1, as expected by the usort function. */ private function tupleSort($a, $b) { $max = max(count($a), count($b)); for($i = 0; $i < $max; ++$i) { if($a[$i] < $b[$i]) { return -1; } else if($a[$i] > $b[$i]) { return 1; } } if(count($a) == $count($b)) { return 0; } else if(count($a) < count($b)) { return -1; } else { return 1; } } } Submit