<?php
namespace Caxy\HtmlDiff;
class HtmlDiff
{
public static $defaultSpecialCaseTags = array('strong', 'b', 'i', 'big', 'small', 'u', 'sub', 'sup', 'strike', 's', 'p');
public static $defaultSpecialCaseChars = array('.', ',', '(', ')', '\'');
public static $defaultGroupDiffs = true;
protected $content;
protected $oldText;
protected $newText;
protected $oldWords = array();
protected $newWords = array();
protected $wordIndices;
protected $encoding;
protected $specialCaseOpeningTags = array();
protected $specialCaseClosingTags = array();
protected $specialCaseTags;
protected $specialCaseChars;
protected $groupDiffs;
protected $insertSpaceInReplace = false;
public function __construct($oldText, $newText, $encoding = 'UTF-8', $specialCaseTags = null, $groupDiffs = null)
{
if ($specialCaseTags === null) {
$specialCaseTags = static::$defaultSpecialCaseTags;
}
if ($groupDiffs === null) {
$groupDiffs = static::$defaultGroupDiffs;
}
$this->oldText = $this->purifyHtml(trim($oldText));
$this->newText = $this->purifyHtml(trim($newText));
$this->encoding = $encoding;
$this->content = '';
$this->groupDiffs = $groupDiffs;
$this->setSpecialCaseTags($specialCaseTags);
$this->setSpecialCaseChars(static::$defaultSpecialCaseChars);
}
/**
* @param boolean $boolean
* @return HtmlDiff
*/
public function setInsertSpaceInReplace($boolean)
{
$this->insertSpaceInReplace = $boolean;
return $this;
}
/**
* @return boolean
*/
public function getInsertSpaceInReplace()
{
return $this->insertSpaceInReplace;
}
public function setSpecialCaseChars(array $chars)
{
$this->specialCaseChars = $chars;
}
public function getSpecialCaseChars()
{
return $this->specialCaseChars;
}
public function addSpecialCaseChar($char)
{
if (!in_array($char, $this->specialCaseChars)) {
$this->specialCaseChars[] = $char;
}
}
public function removeSpecialCaseChar($char)
{
$key = array_search($char, $this->specialCaseChars);
if ($key !== false) {
unset($this->specialCaseChars[$key]);
}
}
public function setSpecialCaseTags(array $tags = array())
{
$this->specialCaseTags = $tags;
foreach ($this->specialCaseTags as $tag) {
$this->addSpecialCaseTag($tag);
}
}
public function addSpecialCaseTag($tag)
{
if (!in_array($tag, $this->specialCaseTags)) {
$this->specialCaseTags[] = $tag;
}
$opening = $this->getOpeningTag($tag);
$closing = $this->getClosingTag($tag);
if (!in_array($opening, $this->specialCaseOpeningTags)) {
$this->specialCaseOpeningTags[] = $opening;
}
if (!in_array($closing, $this->specialCaseClosingTags)) {
$this->specialCaseClosingTags[] = $closing;
}
}
public function removeSpecialCaseTag($tag)
{
if (($key = array_search($tag, $this->specialCaseTags)) !== false) {
unset($this->specialCaseTags[$key]);
$opening = $this->getOpeningTag($tag);
$closing = $this->getClosingTag($tag);
if (($key = array_search($opening, $this->specialCaseOpeningTags)) !== false) {
unset($this->specialCaseOpeningTags[$key]);
}
if (($key = array_search($closing, $this->specialCaseClosingTags)) !== false) {
unset($this->specialCaseClosingTags[$key]);
}
}
}
public function getSpecialCaseTags()
{
return $this->specialCaseTags;
}
public function getOldHtml()
{
return $this->oldText;
}
public function getNewHtml()
{
return $this->newText;
}
public function getDifference()
{
return $this->content;
}
public function setGroupDiffs($boolean)
{
$this->groupDiffs = $boolean;
}
public function isGroupDiffs()
{
return $this->groupDiffs;
}
protected function getOpeningTag($tag)
{
return "/<".$tag."[^>]*/i";
}
protected function getClosingTag($tag)
{
return "</".$tag.">";
}
protected function getStringBetween($str, $start, $end)
{
$expStr = explode( $start, $str, 2 );
if ( count( $expStr ) > 1 ) {
$expStr = explode( $end, $expStr[ 1 ] );
if ( count( $expStr ) > 1 ) {
array_pop( $expStr );
return implode( $end, $expStr );
}
}
return '';
}
protected function purifyHtml($html, $tags = null)
{
if ( class_exists( 'Tidy' ) && false ) {
$config = array( 'output-xhtml' => true, 'indent' => false );
$tidy = new tidy;
$tidy->parseString( $html, $config, 'utf8' );
$html = (string) $tidy;
return $this->getStringBetween( $html, '<body>' );
}
return $html;
}
public function build()
{
$this->splitInputsToWords();
$this->indexNewWords();
$operations = $this->operations();
foreach ($operations as $item) {
$this->performOperation( $item );
}
return $this->content;
}
protected function indexNewWords()
{
$this->wordIndices = array();
foreach ($this->newWords as $i => $word) {
if ( $this->isTag( $word ) ) {
$word = $this->stripTagAttributes( $word );
}
if ( isset( $this->wordIndices[ $word ] ) ) {
$this->wordIndices[ $word ][] = $i;
} else {
$this->wordIndices[ $word ] = array( $i );
}
}
}
protected function splitInputsToWords()
{
$this->oldWords = $this->convertHtmlToListOfWords( $this->explode( $this->oldText ) );
$this->newWords = $this->convertHtmlToListOfWords( $this->explode( $this->newText ) );
}
protected function isPartOfWord($text)
{
return ctype_alnum(str_replace($this->specialCaseChars, '', $text));
}
protected function convertHtmlToListOfWords($characterString)
{
$mode = 'character';
$current_word = '';
$words = array();
foreach ($characterString as $i => $character) {
switch ($mode) {
case 'character':
if ( $this->isStartOfTag( $character ) ) {
if ($current_word != '') {
$words[] = $current_word;
}
$current_word = "<";
$mode = 'tag';
} elseif ( preg_match( "[^\s]", $character ) > 0 ) {
if ($current_word != '') {
$words[] = $current_word;
}
$current_word = $character;
$mode = 'whitespace';
} else {
if (
(ctype_alnum($character) && (strlen($current_word) == 0 || $this->isPartOfWord($current_word))) ||
(in_array($character, $this->specialCaseChars) && isset($characterString[$i+1]) && $this->isPartOfWord($characterString[$i+1]))
) {
$current_word .= $character;
} else {
$words[] = $current_word;
$current_word = $character;
}
}
break;
case 'tag' :
if ( $this->isEndOfTag( $character ) ) {
$current_word .= ">";
$words[] = $current_word;
$current_word = "";
if ( !preg_match('[^\s]', $character ) ) {
$mode = 'whitespace';
} else {
$mode = 'character';
}
} else {
$current_word .= $character;
}
break;
case 'whitespace':
if ( $this->isStartOfTag( $character ) ) {
if ($current_word != '') {
$words[] = $current_word;
}
$current_word = "<";
$mode = 'tag';
} elseif ( preg_match( "[^\s]", $character ) ) {
$current_word .= $character;
} else {
if ($current_word != '') {
$words[] = $current_word;
}
$current_word = $character;
$mode = 'character';
}
break;
default:
break;
}
}
if ($current_word != '') {
$words[] = $current_word;
}
return $words;
}
protected function isStartOfTag($val)
{
return $val == "<";
}
protected function isEndOfTag($val)
{
return $val == ">";
}
protected function isWhiteSpace($value)
{
return !preg_match( '[^\s]', $value );
}
protected function explode($value)
{
// as suggested by @onassar
return preg_split( '//u', $value );
}
protected function performOperation($operation)
{
switch ($operation->action) {
case 'equal' :
$this->processEqualOperation( $operation );
break;
case 'delete' :
$this->processDeleteOperation( $operation, "diffdel" );
break;
case 'insert' :
$this->processInsertOperation( $operation, "diffins");
break;
case 'replace':
$this->processReplaceOperation( $operation );
break;
default:
break;
}
}
protected function processReplaceOperation($operation)
{
$processDelete = strlen($this->oldText) > 0;
$processInsert = strlen($this->newText) > 0;
if ($processDelete) {
$this->processDeleteOperation( $operation, "diffmod" );
}
if ($this->insertSpaceInReplace && $processDelete && $processInsert) {
$this->content .= ' ';
}
if ($processInsert) {
$this->processInsertOperation( $operation, "diffmod" );
}
}
protected function processInsertOperation($operation, $cssClass)
{
$text = array();
foreach ($this->newWords as $pos => $s) {
if ($pos >= $operation->startInNew && $pos < $operation->endInNew) {
$text[] = $s;
}
}
$this->insertTag( "ins", $cssClass, $text );
}
protected function processDeleteOperation($operation, $cssClass)
{
$text = array();
foreach ($this->oldWords as $pos => $s) {
if ($pos >= $operation->startInOld && $pos < $operation->endInOld) {
$text[] = $s;
}
}
$this->insertTag( "del", $cssClass, $text );
}
protected function processEqualOperation($operation)
{
$result = array();
foreach ($this->newWords as $pos => $s) {
if ($pos >= $operation->startInNew && $pos < $operation->endInNew) {
$result[] = $s;
}
}
$this->content .= implode( "", $result );
}
protected function insertTag($tag, $cssClass, &$words)
{
while (true) {
if ( count( $words ) == 0 ) {
break;
}
$nonTags = $this->extractConsecutiveWords( $words, 'noTag' );
$specialCaseTagInjection = '';
$specialCaseTagInjectionIsBefore = false;
if ( count( $nonTags ) != 0 ) {
$text = $this->wrapText( implode( "", $nonTags ), $tag, $cssClass );
$this->content .= $text;
} else {
$firstOrDefault = false;
foreach ($this->specialCaseOpeningTags as $x) {
if ( preg_match( $x, $words[ 0 ] ) ) {
$firstOrDefault = $x;
break;
}
}
if ($firstOrDefault) {
$specialCaseTagInjection = '<ins class="mod">';
if ($tag == "del") {
unset( $words[ 0 ] );
}
} elseif ( array_search( $words[ 0 ], $this->specialCaseClosingTags ) !== false ) {
$specialCaseTagInjection = "</ins>";
$specialCaseTagInjectionIsBefore = true;
if ($tag == "del") {
unset( $words[ 0 ] );
}
}
}
if ( count( $words ) == 0 && count( $specialCaseTagInjection ) == 0 ) {
break;
}
if ($specialCaseTagInjectionIsBefore) {
$this->content .= $specialCaseTagInjection . implode( "", $this->extractConsecutiveWords( $words, 'tag' ) );
} else {
$workTag = $this->extractConsecutiveWords( $words, 'tag' );
if ( isset( $workTag[ 0 ] ) && $this->isOpeningTag( $workTag[ 0 ] ) && !$this->isClosingTag( $workTag[ 0 ] ) ) {
if ( strpos( $workTag[ 0 ], 'class=' ) ) {
$workTag[ 0 ] = str_replace( 'class="', 'class="diffmod ', $workTag[ 0 ] );
$workTag[ 0 ] = str_replace( "class='", 'class="diffmod ', $workTag[ 0 ] );
} else {
$workTag[ 0 ] = str_replace( ">", ' class="diffmod">', $workTag[ 0 ] );
}
}
$this->content .= implode( "", $workTag ) . $specialCaseTagInjection;
}
}
}
protected function checkCondition($word, $condition)
{
return $condition == 'tag' ? $this->isTag( $word ) : !$this->isTag( $word );
}
protected function wrapText($text, $tagName, $cssClass)
{
return sprintf( '<%1$s class="%2$s">%3$s</%1$s>', $tagName, $cssClass, $text );
}
protected function extractConsecutiveWords(&$words, $condition)
{
$indexOfFirstTag = null;
foreach ($words as $i => $word) {
if ( !$this->checkCondition( $word, $condition ) ) {
$indexOfFirstTag = $i;
break;
}
}
if ($indexOfFirstTag !== null) {
$items = array();
foreach ($words as $pos => $s) {
if ($pos >= 0 && $pos < $indexOfFirstTag) {
$items[] = $s;
}
}
if ($indexOfFirstTag > 0) {
array_splice( $words, 0, $indexOfFirstTag );
}
return $items;
} else {
$items = array();
foreach ($words as $pos => $s) {
if ( $pos >= 0 && $pos <= count( $words ) ) {
$items[] = $s;
}
}
array_splice( $words, 0, count( $words ) );
return $items;
}
}
protected function isTag($item)
{
return $this->isOpeningTag( $item ) || $this->isClosingTag( $item );
}
protected function isOpeningTag($item)
{
return preg_match( "#<[^>]+>\\s*#iU", $item );
}
protected function isClosingTag($item)
{
return preg_match( "#</[^>]+>\\s*#iU", $item );
}
protected function operations()
{
$positionInOld = 0;
$positionInNew = 0;
$operations = array();
$matches = $this->matchingBlocks();
$matches[] = new Match( count( $this->oldWords ), count( $this->newWords ), 0 );
foreach ($matches as $i => $match) {
$matchStartsAtCurrentPositionInOld = ( $positionInOld == $match->startInOld );
$matchStartsAtCurrentPositionInNew = ( $positionInNew == $match->startInNew );
$action = 'none';
if ($matchStartsAtCurrentPositionInOld == false && $matchStartsAtCurrentPositionInNew == false) {
$action = 'replace';
} elseif ($matchStartsAtCurrentPositionInOld == true && $matchStartsAtCurrentPositionInNew == false) {
$action = 'insert';
} elseif ($matchStartsAtCurrentPositionInOld == false && $matchStartsAtCurrentPositionInNew == true) {
$action = 'delete';
} else { // This occurs if the first few words are the same in both versions
$action = 'none';
}
if ($action != 'none') {
$operations[] = new Operation( $action, $positionInOld, $match->startInOld, $positionInNew, $match->startInNew );
}
if ( count( $match ) != 0 ) {
$operations[] = new Operation( 'equal', $match->startInOld, $match->endInOld(), $match->startInNew, $match->endInNew() );
}
$positionInOld = $match->endInOld();
$positionInNew = $match->endInNew();
}
return $operations;
}
protected function matchingBlocks()
{
$matchingBlocks = array();
$this->findMatchingBlocks( 0, count( $this->oldWords ), 0, count( $this->newWords ), $matchingBlocks );
return $matchingBlocks;
}
protected function findMatchingBlocks($startInOld, $endInOld, $startInNew, $endInNew, &$matchingBlocks)
{
$match = $this->findMatch( $startInOld, $endInOld, $startInNew, $endInNew );
if ($match !== null) {
if ($startInOld < $match->startInOld && $startInNew < $match->startInNew) {
$this->findMatchingBlocks( $startInOld, $match->startInOld, $startInNew, $match->startInNew, $matchingBlocks );
}
$matchingBlocks[] = $match;
if ( $match->endInOld() < $endInOld && $match->endInNew() < $endInNew ) {
$this->findMatchingBlocks( $match->endInOld(), $endInOld, $match->endInNew(), $endInNew, $matchingBlocks );
}
}
}
protected function stripTagAttributes($word)
{
$word = explode( ' ', trim( $word, '<>' ) );
return '<' . $word[ 0 ] . '>';
}
protected function findMatch($startInOld, $endInOld, $startInNew, $endInNew)
{
$bestMatchInOld = $startInOld;
$bestMatchInNew = $startInNew;
$bestMatchSize = 0;
$matchLengthAt = array();
for ($indexInOld = $startInOld; $indexInOld < $endInOld; $indexInOld++) {
$newMatchLengthAt = array();
$index = $this->oldWords[ $indexInOld ];
if ( $this->isTag( $index ) ) {
$index = $this->stripTagAttributes( $index );
}
if ( !isset( $this->wordIndices[ $index ] ) ) {
$matchLengthAt = $newMatchLengthAt;
continue;
}
foreach ($this->wordIndices[ $index ] as $indexInNew) {
if ($indexInNew < $startInNew) {
continue;
}
if ($indexInNew >= $endInNew) {
break;
}
$newMatchLength = ( isset( $matchLengthAt[ $indexInNew - 1 ] ) ? $matchLengthAt[ $indexInNew - 1 ] : 0 ) + 1;
$newMatchLengthAt[ $indexInNew ] = $newMatchLength;
if ($newMatchLength > $bestMatchSize) {
$bestMatchInOld = $indexInOld - $newMatchLength + 1;
$bestMatchInNew = $indexInNew - $newMatchLength + 1;
$bestMatchSize = $newMatchLength;
}
}
$matchLengthAt = $newMatchLengthAt;
}
// Skip match if none found or match consists only of whitespace
if ($bestMatchSize != 0 &&
(
!$this->isGroupDiffs() ||
!preg_match('/^\s+$/', implode('', array_slice($this->oldWords, $bestMatchInOld, $bestMatchSize)))
)
) {
return new Match($bestMatchInOld, $bestMatchInNew, $bestMatchSize);
}
return null;
}
}
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