689 lines
22 KiB
PHP
689 lines
22 KiB
PHP
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<?php
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/**
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* FINE granularity DIFF
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*
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* Computes a set of instructions to convert the content of
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* one string into another.
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*
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* Copyright (c) 2011 Raymond Hill (http://raymondhill.net/blog/?p=441)
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*
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* Licensed under The MIT License
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*
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* Permission is hereby granted, free of charge, to any person obtaining a copy
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* of this software and associated documentation files (the "Software"), to deal
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* in the Software without restriction, including without limitation the rights
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* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
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* copies of the Software, and to permit persons to whom the Software is
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* furnished to do so, subject to the following conditions:
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*
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* The above copyright notice and this permission notice shall be included in
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* all copies or substantial portions of the Software.
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*
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* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
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* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
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* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
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* THE SOFTWARE.
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*
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* @copyright Copyright 2011 (c) Raymond Hill (http://raymondhill.net/blog/?p=441)
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* @link http://www.raymondhill.net/finediff/
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* @version 0.6
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* @license MIT License (http://www.opensource.org/licenses/mit-license.php)
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*/
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/**
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* Usage (simplest):
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*
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* include 'finediff.php';
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*
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* // for the stock stack, granularity values are:
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* // FineDiff::$paragraphGranularity = paragraph/line level
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* // FineDiff::$sentenceGranularity = sentence level
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* // FineDiff::$wordGranularity = word level
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* // FineDiff::$characterGranularity = character level [default]
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*
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* $opcodes = FineDiff::getDiffOpcodes($from_text, $to_text [, $granularityStack = null] );
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* // store opcodes for later use...
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*
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* ...
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*
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* // restore $to_text from $from_text + $opcodes
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* include 'finediff.php';
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* $to_text = FineDiff::renderToTextFromOpcodes($from_text, $opcodes);
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*
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* ...
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*/
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/**
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* Persisted opcodes (string) are a sequence of atomic opcode.
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* A single opcode can be one of the following:
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* c | c{n} | d | d{n} | i:{c} | i{length}:{s}
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* 'c' = copy one character from source
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* 'c{n}' = copy n characters from source
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* 'd' = skip one character from source
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* 'd{n}' = skip n characters from source
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* 'i:{c} = insert character 'c'
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* 'i{n}:{s}' = insert string s, which is of length n
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*
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* Do not exist as of now, under consideration:
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* 'm{n}:{o} = move n characters from source o characters ahead.
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* It would be essentially a shortcut for a delete->copy->insert
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* command (swap) for when the inserted segment is exactly the same
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* as the deleted one, and with only a copy operation in between.
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* TODO: How often this case occurs? Is it worth it? Can only
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* be done as a postprocessing method (->optimize()?)
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*/
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abstract class FineDiffOp {
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abstract public function getFromLen();
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abstract public function getToLen();
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abstract public function getOpcode();
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}
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class FineDiffDeleteOp extends FineDiffOp {
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public function __construct($len) {
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$this->fromLen = $len;
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}
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public function getFromLen() {
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return $this->fromLen;
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}
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public function getToLen() {
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return 0;
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}
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public function getOpcode() {
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if ( $this->fromLen === 1 ) {
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return 'd';
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}
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return "d{$this->fromLen}";
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}
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}
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class FineDiffInsertOp extends FineDiffOp {
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public function __construct($text) {
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$this->text = $text;
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}
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public function getFromLen() {
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return 0;
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}
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public function getToLen() {
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return strlen($this->text);
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}
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public function getText() {
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return $this->text;
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}
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public function getOpcode() {
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$to_len = strlen($this->text);
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if ( $to_len === 1 ) {
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return "i:{$this->text}";
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}
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return "i{$to_len}:{$this->text}";
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}
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}
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class FineDiffReplaceOp extends FineDiffOp {
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public function __construct($fromLen, $text) {
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$this->fromLen = $fromLen;
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$this->text = $text;
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}
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public function getFromLen() {
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return $this->fromLen;
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}
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public function getToLen() {
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return strlen($this->text);
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}
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public function getText() {
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return $this->text;
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}
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public function getOpcode() {
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if ( $this->fromLen === 1 ) {
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$del_opcode = 'd';
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}
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else {
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$del_opcode = "d{$this->fromLen}";
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}
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$to_len = strlen($this->text);
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if ( $to_len === 1 ) {
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return "{$del_opcode}i:{$this->text}";
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}
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return "{$del_opcode}i{$to_len}:{$this->text}";
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}
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}
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class FineDiffCopyOp extends FineDiffOp {
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public function __construct($len) {
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$this->len = $len;
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}
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public function getFromLen() {
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return $this->len;
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}
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public function getToLen() {
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return $this->len;
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}
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public function getOpcode() {
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if ( $this->len === 1 ) {
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return 'c';
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}
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return "c{$this->len}";
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}
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public function increase($size) {
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return $this->len += $size;
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}
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}
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/**
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* FineDiff ops
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*
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* Collection of ops
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*/
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class FineDiffOps {
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public function appendOpcode($opcode, $from, $from_offset, $from_len) {
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if ( $opcode === 'c' ) {
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$edits[] = new FineDiffCopyOp($from_len);
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}
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else if ( $opcode === 'd' ) {
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$edits[] = new FineDiffDeleteOp($from_len);
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}
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else /* if ( $opcode === 'i' ) */ {
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$edits[] = new FineDiffInsertOp(substr($from, $from_offset, $from_len));
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}
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}
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public $edits = array();
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}
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/**
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* FineDiff class
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*
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* TODO: Document
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*
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*/
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class FineDiff {
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/**------------------------------------------------------------------------
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*
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* Public section
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*
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*/
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/**
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* Constructor
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* ...
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* The $granularityStack allows FineDiff to be configurable so that
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* a particular stack tailored to the specific content of a document can
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* be passed.
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*/
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public function __construct($from_text = '', $to_text = '', $granularityStack = null) {
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// setup stack for generic text documents by default
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$this->granularityStack = $granularityStack ? $granularityStack : FineDiff::$characterGranularity;
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$this->edits = array();
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$this->from_text = $from_text;
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$this->doDiff($from_text, $to_text);
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}
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public function getOps() {
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return $this->edits;
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}
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public function getOpcodes() {
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$opcodes = array();
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foreach ( $this->edits as $edit ) {
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$opcodes[] = $edit->getOpcode();
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}
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return implode('', $opcodes);
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}
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public function renderDiffToHTML() {
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$in_offset = 0;
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ob_start();
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foreach ( $this->edits as $edit ) {
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$n = $edit->getFromLen();
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if ( $edit instanceof FineDiffCopyOp ) {
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FineDiff::renderDiffToHTMLFromOpcode('c', $this->from_text, $in_offset, $n);
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}
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else if ( $edit instanceof FineDiffDeleteOp ) {
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FineDiff::renderDiffToHTMLFromOpcode('d', $this->from_text, $in_offset, $n);
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}
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else if ( $edit instanceof FineDiffInsertOp ) {
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FineDiff::renderDiffToHTMLFromOpcode('i', $edit->getText(), 0, $edit->getToLen());
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}
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else /* if ( $edit instanceof FineDiffReplaceOp ) */ {
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FineDiff::renderDiffToHTMLFromOpcode('d', $this->from_text, $in_offset, $n);
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FineDiff::renderDiffToHTMLFromOpcode('i', $edit->getText(), 0, $edit->getToLen());
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}
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$in_offset += $n;
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}
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return ob_get_clean();
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}
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/**------------------------------------------------------------------------
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* Return an opcodes string describing the diff between a "From" and a
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* "To" string
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*/
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public static function getDiffOpcodes($from, $to, $granularities = null) {
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$diff = new FineDiff($from, $to, $granularities);
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return $diff->getOpcodes();
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}
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/**------------------------------------------------------------------------
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* Return an iterable collection of diff ops from an opcodes string
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*/
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public static function getDiffOpsFromOpcodes($opcodes) {
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$diffops = new FineDiffOps();
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FineDiff::renderFromOpcodes(null, $opcodes, array($diffops,'appendOpcode'));
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return $diffops->edits;
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}
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/**------------------------------------------------------------------------
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* Re-create the "To" string from the "From" string and an "Opcodes" string
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*/
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public static function renderToTextFromOpcodes($from, $opcodes) {
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ob_start();
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FineDiff::renderFromOpcodes($from, $opcodes, array('FineDiff','renderToTextFromOpcode'));
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return ob_get_clean();
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}
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/**------------------------------------------------------------------------
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* Render the diff to an HTML string
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*/
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public static function renderDiffToHTMLFromOpcodes($from, $opcodes) {
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ob_start();
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FineDiff::renderFromOpcodes($from, $opcodes, array('FineDiff','renderDiffToHTMLFromOpcode'));
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return ob_get_clean();
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}
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/**------------------------------------------------------------------------
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* Generic opcodes parser, user must supply callback for handling
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* single opcode
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*/
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public static function renderFromOpcodes($from, $opcodes, $callback) {
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if ( !is_callable($callback) ) {
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return;
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}
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$opcodes_len = strlen($opcodes);
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$from_offset = $opcodes_offset = 0;
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while ( $opcodes_offset < $opcodes_len ) {
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$opcode = substr($opcodes, $opcodes_offset, 1);
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$opcodes_offset++;
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$n = intval(substr($opcodes, $opcodes_offset));
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if ( $n ) {
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$opcodes_offset += strlen(strval($n));
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}
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else {
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$n = 1;
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}
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if ( $opcode === 'c' ) { // copy n characters from source
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call_user_func($callback, 'c', $from, $from_offset, $n, '');
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$from_offset += $n;
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}
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else if ( $opcode === 'd' ) { // delete n characters from source
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call_user_func($callback, 'd', $from, $from_offset, $n, '');
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$from_offset += $n;
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}
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else /* if ( $opcode === 'i' ) */ { // insert n characters from opcodes
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call_user_func($callback, 'i', $opcodes, $opcodes_offset + 1, $n);
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$opcodes_offset += 1 + $n;
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}
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}
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}
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/**
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* Stock granularity stacks and delimiters
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*/
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const paragraphDelimiters = "\n\r";
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public static $paragraphGranularity = array(
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FineDiff::paragraphDelimiters
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);
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const sentenceDelimiters = ".\n\r";
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public static $sentenceGranularity = array(
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FineDiff::paragraphDelimiters,
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FineDiff::sentenceDelimiters
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);
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const wordDelimiters = " \t.\n\r";
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public static $wordGranularity = array(
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FineDiff::paragraphDelimiters,
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FineDiff::sentenceDelimiters,
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FineDiff::wordDelimiters
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);
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const characterDelimiters = "";
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public static $characterGranularity = array(
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FineDiff::paragraphDelimiters,
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FineDiff::sentenceDelimiters,
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FineDiff::wordDelimiters,
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FineDiff::characterDelimiters
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);
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public static $textStack = array(
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".",
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" \t.\n\r",
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""
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);
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/**------------------------------------------------------------------------
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*
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* Private section
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*
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*/
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/**
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* Entry point to compute the diff.
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*/
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private function doDiff($from_text, $to_text) {
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$this->last_edit = false;
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$this->stackpointer = 0;
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$this->from_text = $from_text;
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$this->from_offset = 0;
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// can't diff without at least one granularity specifier
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if ( empty($this->granularityStack) ) {
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return;
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}
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$this->_processGranularity($from_text, $to_text);
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}
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|
||
|
|
/**
|
||
|
|
* This is the recursive function which is responsible for
|
||
|
|
* handling/increasing granularity.
|
||
|
|
*
|
||
|
|
* Incrementally increasing the granularity is key to compute the
|
||
|
|
* overall diff in a very efficient way.
|
||
|
|
*/
|
||
|
|
private function _processGranularity($from_segment, $to_segment) {
|
||
|
|
$delimiters = $this->granularityStack[$this->stackpointer++];
|
||
|
|
$has_next_stage = $this->stackpointer < count($this->granularityStack);
|
||
|
|
foreach ( FineDiff::doFragmentDiff($from_segment, $to_segment, $delimiters) as $fragment_edit ) {
|
||
|
|
// increase granularity
|
||
|
|
if ( $fragment_edit instanceof FineDiffReplaceOp && $has_next_stage ) {
|
||
|
|
$this->_processGranularity(
|
||
|
|
substr($this->from_text, $this->from_offset, $fragment_edit->getFromLen()),
|
||
|
|
$fragment_edit->getText()
|
||
|
|
);
|
||
|
|
}
|
||
|
|
// fuse copy ops whenever possible
|
||
|
|
else if ( $fragment_edit instanceof FineDiffCopyOp && $this->last_edit instanceof FineDiffCopyOp ) {
|
||
|
|
$this->edits[count($this->edits)-1]->increase($fragment_edit->getFromLen());
|
||
|
|
$this->from_offset += $fragment_edit->getFromLen();
|
||
|
|
}
|
||
|
|
else {
|
||
|
|
/* $fragment_edit instanceof FineDiffCopyOp */
|
||
|
|
/* $fragment_edit instanceof FineDiffDeleteOp */
|
||
|
|
/* $fragment_edit instanceof FineDiffInsertOp */
|
||
|
|
$this->edits[] = $this->last_edit = $fragment_edit;
|
||
|
|
$this->from_offset += $fragment_edit->getFromLen();
|
||
|
|
}
|
||
|
|
}
|
||
|
|
$this->stackpointer--;
|
||
|
|
}
|
||
|
|
|
||
|
|
/**
|
||
|
|
* This is the core algorithm which actually perform the diff itself,
|
||
|
|
* fragmenting the strings as per specified delimiters.
|
||
|
|
*
|
||
|
|
* This function is naturally recursive, however for performance purpose
|
||
|
|
* a local job queue is used instead of outright recursivity.
|
||
|
|
*/
|
||
|
|
private static function doFragmentDiff($from_text, $to_text, $delimiters) {
|
||
|
|
// Empty delimiter means character-level diffing.
|
||
|
|
// In such case, use code path optimized for character-level
|
||
|
|
// diffing.
|
||
|
|
if ( empty($delimiters) ) {
|
||
|
|
return FineDiff::doCharDiff($from_text, $to_text);
|
||
|
|
}
|
||
|
|
|
||
|
|
$result = array();
|
||
|
|
|
||
|
|
// fragment-level diffing
|
||
|
|
$from_text_len = strlen($from_text);
|
||
|
|
$to_text_len = strlen($to_text);
|
||
|
|
$from_fragments = FineDiff::extractFragments($from_text, $delimiters);
|
||
|
|
$to_fragments = FineDiff::extractFragments($to_text, $delimiters);
|
||
|
|
|
||
|
|
$jobs = array(array(0, $from_text_len, 0, $to_text_len));
|
||
|
|
|
||
|
|
$cached_array_keys = array();
|
||
|
|
|
||
|
|
while ( $job = array_pop($jobs) ) {
|
||
|
|
|
||
|
|
// get the segments which must be diff'ed
|
||
|
|
list($from_segment_start, $from_segment_end, $to_segment_start, $to_segment_end) = $job;
|
||
|
|
|
||
|
|
// catch easy cases first
|
||
|
|
$from_segment_length = $from_segment_end - $from_segment_start;
|
||
|
|
$to_segment_length = $to_segment_end - $to_segment_start;
|
||
|
|
if ( !$from_segment_length || !$to_segment_length ) {
|
||
|
|
if ( $from_segment_length ) {
|
||
|
|
$result[$from_segment_start * 4] = new FineDiffDeleteOp($from_segment_length);
|
||
|
|
}
|
||
|
|
else if ( $to_segment_length ) {
|
||
|
|
$result[$from_segment_start * 4 + 1] = new FineDiffInsertOp(substr($to_text, $to_segment_start, $to_segment_length));
|
||
|
|
}
|
||
|
|
continue;
|
||
|
|
}
|
||
|
|
|
||
|
|
// find longest copy operation for the current segments
|
||
|
|
$best_copy_length = 0;
|
||
|
|
|
||
|
|
$from_base_fragment_index = $from_segment_start;
|
||
|
|
|
||
|
|
$cached_array_keys_for_current_segment = array();
|
||
|
|
|
||
|
|
while ( $from_base_fragment_index < $from_segment_end ) {
|
||
|
|
$from_base_fragment = $from_fragments[$from_base_fragment_index];
|
||
|
|
$from_base_fragment_length = strlen($from_base_fragment);
|
||
|
|
// performance boost: cache array keys
|
||
|
|
if ( !isset($cached_array_keys_for_current_segment[$from_base_fragment]) ) {
|
||
|
|
if ( !isset($cached_array_keys[$from_base_fragment]) ) {
|
||
|
|
$to_all_fragment_indices = $cached_array_keys[$from_base_fragment] = array_keys($to_fragments, $from_base_fragment, true);
|
||
|
|
}
|
||
|
|
else {
|
||
|
|
$to_all_fragment_indices = $cached_array_keys[$from_base_fragment];
|
||
|
|
}
|
||
|
|
// get only indices which falls within current segment
|
||
|
|
if ( $to_segment_start > 0 || $to_segment_end < $to_text_len ) {
|
||
|
|
$to_fragment_indices = array();
|
||
|
|
foreach ( $to_all_fragment_indices as $to_fragment_index ) {
|
||
|
|
if ( $to_fragment_index < $to_segment_start ) { continue; }
|
||
|
|
if ( $to_fragment_index >= $to_segment_end ) { break; }
|
||
|
|
$to_fragment_indices[] = $to_fragment_index;
|
||
|
|
}
|
||
|
|
$cached_array_keys_for_current_segment[$from_base_fragment] = $to_fragment_indices;
|
||
|
|
}
|
||
|
|
else {
|
||
|
|
$to_fragment_indices = $to_all_fragment_indices;
|
||
|
|
}
|
||
|
|
}
|
||
|
|
else {
|
||
|
|
$to_fragment_indices = $cached_array_keys_for_current_segment[$from_base_fragment];
|
||
|
|
}
|
||
|
|
// iterate through collected indices
|
||
|
|
foreach ( $to_fragment_indices as $to_base_fragment_index ) {
|
||
|
|
$fragment_index_offset = $from_base_fragment_length;
|
||
|
|
// iterate until no more match
|
||
|
|
for (;;) {
|
||
|
|
$fragment_from_index = $from_base_fragment_index + $fragment_index_offset;
|
||
|
|
if ( $fragment_from_index >= $from_segment_end ) {
|
||
|
|
break;
|
||
|
|
}
|
||
|
|
$fragment_to_index = $to_base_fragment_index + $fragment_index_offset;
|
||
|
|
if ( $fragment_to_index >= $to_segment_end ) {
|
||
|
|
break;
|
||
|
|
}
|
||
|
|
if ( $from_fragments[$fragment_from_index] !== $to_fragments[$fragment_to_index] ) {
|
||
|
|
break;
|
||
|
|
}
|
||
|
|
$fragment_length = strlen($from_fragments[$fragment_from_index]);
|
||
|
|
$fragment_index_offset += $fragment_length;
|
||
|
|
}
|
||
|
|
if ( $fragment_index_offset > $best_copy_length ) {
|
||
|
|
$best_copy_length = $fragment_index_offset;
|
||
|
|
$best_from_start = $from_base_fragment_index;
|
||
|
|
$best_to_start = $to_base_fragment_index;
|
||
|
|
}
|
||
|
|
}
|
||
|
|
$from_base_fragment_index += strlen($from_base_fragment);
|
||
|
|
// If match is larger than half segment size, no point trying to find better
|
||
|
|
// TODO: Really?
|
||
|
|
if ( $best_copy_length >= $from_segment_length / 2) {
|
||
|
|
break;
|
||
|
|
}
|
||
|
|
// no point to keep looking if what is left is less than
|
||
|
|
// current best match
|
||
|
|
if ( $from_base_fragment_index + $best_copy_length >= $from_segment_end ) {
|
||
|
|
break;
|
||
|
|
}
|
||
|
|
}
|
||
|
|
|
||
|
|
if ( $best_copy_length ) {
|
||
|
|
$jobs[] = array($from_segment_start, $best_from_start, $to_segment_start, $best_to_start);
|
||
|
|
$result[$best_from_start * 4 + 2] = new FineDiffCopyOp($best_copy_length);
|
||
|
|
$jobs[] = array($best_from_start + $best_copy_length, $from_segment_end, $best_to_start + $best_copy_length, $to_segment_end);
|
||
|
|
}
|
||
|
|
else {
|
||
|
|
$result[$from_segment_start * 4 ] = new FineDiffReplaceOp($from_segment_length, substr($to_text, $to_segment_start, $to_segment_length));
|
||
|
|
}
|
||
|
|
}
|
||
|
|
|
||
|
|
ksort($result, SORT_NUMERIC);
|
||
|
|
return array_values($result);
|
||
|
|
}
|
||
|
|
|
||
|
|
/**
|
||
|
|
* Perform a character-level diff.
|
||
|
|
*
|
||
|
|
* The algorithm is quite similar to doFragmentDiff(), except that
|
||
|
|
* the code path is optimized for character-level diff -- strpos() is
|
||
|
|
* used to find out the longest common subequence of characters.
|
||
|
|
*
|
||
|
|
* We try to find a match using the longest possible subsequence, which
|
||
|
|
* is at most the length of the shortest of the two strings, then incrementally
|
||
|
|
* reduce the size until a match is found.
|
||
|
|
*
|
||
|
|
* I still need to study more the performance of this function. It
|
||
|
|
* appears that for long strings, the generic doFragmentDiff() is more
|
||
|
|
* performant. For word-sized strings, doCharDiff() is somewhat more
|
||
|
|
* performant.
|
||
|
|
*/
|
||
|
|
private static function doCharDiff($from_text, $to_text) {
|
||
|
|
$result = array();
|
||
|
|
$jobs = array(array(0, strlen($from_text), 0, strlen($to_text)));
|
||
|
|
while ( $job = array_pop($jobs) ) {
|
||
|
|
// get the segments which must be diff'ed
|
||
|
|
list($from_segment_start, $from_segment_end, $to_segment_start, $to_segment_end) = $job;
|
||
|
|
$from_segment_len = $from_segment_end - $from_segment_start;
|
||
|
|
$to_segment_len = $to_segment_end - $to_segment_start;
|
||
|
|
|
||
|
|
// catch easy cases first
|
||
|
|
if ( !$from_segment_len || !$to_segment_len ) {
|
||
|
|
if ( $from_segment_len ) {
|
||
|
|
$result[$from_segment_start * 4 + 0] = new FineDiffDeleteOp($from_segment_len);
|
||
|
|
}
|
||
|
|
else if ( $to_segment_len ) {
|
||
|
|
$result[$from_segment_start * 4 + 1] = new FineDiffInsertOp(substr($to_text, $to_segment_start, $to_segment_len));
|
||
|
|
}
|
||
|
|
continue;
|
||
|
|
}
|
||
|
|
if ( $from_segment_len >= $to_segment_len ) {
|
||
|
|
$copy_len = $to_segment_len;
|
||
|
|
while ( $copy_len ) {
|
||
|
|
$to_copy_start = $to_segment_start;
|
||
|
|
$to_copy_start_max = $to_segment_end - $copy_len;
|
||
|
|
while ( $to_copy_start <= $to_copy_start_max ) {
|
||
|
|
$from_copy_start = strpos(substr($from_text, $from_segment_start, $from_segment_len), substr($to_text, $to_copy_start, $copy_len));
|
||
|
|
if ( $from_copy_start !== false ) {
|
||
|
|
$from_copy_start += $from_segment_start;
|
||
|
|
break 2;
|
||
|
|
}
|
||
|
|
$to_copy_start++;
|
||
|
|
}
|
||
|
|
$copy_len--;
|
||
|
|
}
|
||
|
|
}
|
||
|
|
else {
|
||
|
|
$copy_len = $from_segment_len;
|
||
|
|
while ( $copy_len ) {
|
||
|
|
$from_copy_start = $from_segment_start;
|
||
|
|
$from_copy_start_max = $from_segment_end - $copy_len;
|
||
|
|
while ( $from_copy_start <= $from_copy_start_max ) {
|
||
|
|
$to_copy_start = strpos(substr($to_text, $to_segment_start, $to_segment_len), substr($from_text, $from_copy_start, $copy_len));
|
||
|
|
if ( $to_copy_start !== false ) {
|
||
|
|
$to_copy_start += $to_segment_start;
|
||
|
|
break 2;
|
||
|
|
}
|
||
|
|
$from_copy_start++;
|
||
|
|
}
|
||
|
|
$copy_len--;
|
||
|
|
}
|
||
|
|
}
|
||
|
|
// match found
|
||
|
|
if ( $copy_len ) {
|
||
|
|
$jobs[] = array($from_segment_start, $from_copy_start, $to_segment_start, $to_copy_start);
|
||
|
|
$result[$from_copy_start * 4 + 2] = new FineDiffCopyOp($copy_len);
|
||
|
|
$jobs[] = array($from_copy_start + $copy_len, $from_segment_end, $to_copy_start + $copy_len, $to_segment_end);
|
||
|
|
}
|
||
|
|
// no match, so delete all, insert all
|
||
|
|
else {
|
||
|
|
$result[$from_segment_start * 4] = new FineDiffReplaceOp($from_segment_len, substr($to_text, $to_segment_start, $to_segment_len));
|
||
|
|
}
|
||
|
|
}
|
||
|
|
ksort($result, SORT_NUMERIC);
|
||
|
|
return array_values($result);
|
||
|
|
}
|
||
|
|
|
||
|
|
/**
|
||
|
|
* Efficiently fragment the text into an array according to
|
||
|
|
* specified delimiters.
|
||
|
|
* No delimiters means fragment into single character.
|
||
|
|
* The array indices are the offset of the fragments into
|
||
|
|
* the input string.
|
||
|
|
* A sentinel empty fragment is always added at the end.
|
||
|
|
* Careful: No check is performed as to the validity of the
|
||
|
|
* delimiters.
|
||
|
|
*/
|
||
|
|
private static function extractFragments($text, $delimiters) {
|
||
|
|
// special case: split into characters
|
||
|
|
if ( empty($delimiters) ) {
|
||
|
|
$chars = str_split($text, 1);
|
||
|
|
$chars[strlen($text)] = '';
|
||
|
|
return $chars;
|
||
|
|
}
|
||
|
|
$fragments = array();
|
||
|
|
$start = $end = 0;
|
||
|
|
for (;;) {
|
||
|
|
$end += strcspn($text, $delimiters, $end);
|
||
|
|
$end += strspn($text, $delimiters, $end);
|
||
|
|
if ( $end === $start ) {
|
||
|
|
break;
|
||
|
|
}
|
||
|
|
$fragments[$start] = substr($text, $start, $end - $start);
|
||
|
|
$start = $end;
|
||
|
|
}
|
||
|
|
$fragments[$start] = '';
|
||
|
|
return $fragments;
|
||
|
|
}
|
||
|
|
|
||
|
|
/**
|
||
|
|
* Stock opcode renderers
|
||
|
|
*/
|
||
|
|
private static function renderToTextFromOpcode($opcode, $from, $from_offset, $from_len) {
|
||
|
|
if ( $opcode === 'c' || $opcode === 'i' ) {
|
||
|
|
echo substr($from, $from_offset, $from_len);
|
||
|
|
}
|
||
|
|
}
|
||
|
|
|
||
|
|
private static function renderDiffToHTMLFromOpcode($opcode, $from, $from_offset, $from_len) {
|
||
|
|
if ( $opcode === 'c' ) {
|
||
|
|
echo htmlentities(htmlentities(substr($from, $from_offset, $from_len)));
|
||
|
|
}
|
||
|
|
else if ( $opcode === 'd' ) {
|
||
|
|
$deletion = substr($from, $from_offset, $from_len);
|
||
|
|
if ( strcspn($deletion, " \n\r") === 0 ) {
|
||
|
|
$deletion = str_replace(array("\n","\r"), array('\n','\r'), $deletion);
|
||
|
|
}
|
||
|
|
echo '<del>', htmlentities(htmlentities($deletion)), '</del>';
|
||
|
|
}
|
||
|
|
else /* if ( $opcode === 'i' ) */ {
|
||
|
|
echo '<ins>', htmlentities(htmlentities(substr($from, $from_offset, $from_len))), '</ins>';
|
||
|
|
}
|
||
|
|
}
|
||
|
|
}
|
||
|
|
|