<?php 
if (! defined( 'ABSPATH' ) ) { die( 'Forbidden' ); } 
/** 
 * Diff 
 * 
 * A comprehensive library for generating differences between two strings 
 * in multiple formats (unified, side by side HTML etc) 
 * 
 * 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 nscanDiff 
{ 
	/** 
	 * @var array The "old" sequence to use as the basis for the comparison. 
	 */ 
	private $a = null; 
 
	/** 
	 * @var array The "new" sequence to generate the changes for. 
	 */ 
	private $b = null; 
 
	/** 
	 * @var array Array containing the generated opcodes for the differences between the two items. 
	 */ 
	private $groupedCodes = null; 
 
	/** 
	 * @var array Associative array of the default options available for the diff class and their default value. 
	 */ 
	private $defaultOptions = array( 
		'context' => 3, 
		'ignoreNewLines' => false, 
		'ignoreWhitespace' => false, 
		'ignoreCase' => false 
	); 
 
	/** 
	 * @var array Array of the options that have been applied for generating the diff. 
	 */ 
	private $options = array(); 
 
	/** 
	 * The constructor. 
	 * 
	 * @param array $a Array containing the lines of the first string to compare. 
	 * @param array $b Array containing the lines for the second string to compare. 
	 */ 
	public function __construct($a, $b, $options=array()) 
	{ 
		$this->a = $a; 
		$this->b = $b; 
 
		if (is_array($options)) 
			$this->options = array_merge($this->defaultOptions, $options); 
		else 
			$this->options = $this->defaultOptions; 
	} 
 
	/** 
	 * Render a diff using the supplied rendering class and return it. 
	 * 
	 * @param object $renderer An instance of the rendering object to use for generating the diff. 
	 * @return mixed The generated diff. Exact return value depends on the rendered. 
	 */ 
	public function render(nscanDiff_Renderer_Abstract $renderer) 
	{ 
		$renderer->diff = $this; 
		return $renderer->render(); 
	} 
 
	/** 
	 * Get a range of lines from $start to $end from the first comparison string 
	 * and return them as an array. If no values are supplied, the entire string 
	 * is returned. It's also possible to specify just one line to return only 
	 * that line. 
	 * 
	 * @param int $start The starting number. 
	 * @param int $end The ending number. If not supplied, only the item in $start will be returned. 
	 * @return array Array of all of the lines between the specified range. 
	 */ 
	public function getA($start=0, $end=null) 
	{ 
		if($start == 0 && $end === null) { 
			return $this->a; 
		} 
 
		if($end === null) { 
			$length = 1; 
		} 
		else { 
			$length = $end - $start; 
		} 
 
		return array_slice($this->a, $start, $length); 
 
	} 
 
	/** 
	 * Get a range of lines from $start to $end from the second comparison string 
	 * and return them as an array. If no values are supplied, the entire string 
	 * is returned. It's also possible to specify just one line to return only 
	 * that line. 
	 * 
	 * @param int $start The starting number. 
	 * @param int $end The ending number. If not supplied, only the item in $start will be returned. 
	 * @return array Array of all of the lines between the specified range. 
	 */ 
	public function getB($start=0, $end=null) 
	{ 
		if($start == 0 && $end === null) { 
			return $this->b; 
		} 
 
		if($end === null) { 
			$length = 1; 
		} 
		else { 
			$length = $end - $start; 
		} 
 
		return array_slice($this->b, $start, $length); 
	} 
 
	/** 
	 * Generate a list of the compiled and grouped opcodes for the differences between the 
	 * two strings. Generally called by the renderer, this class instantiates the sequence 
	 * matcher and performs the actual diff generation and return an array of the opcodes 
	 * for it. Once generated, the results are cached in the diff class instance. 
	 * 
	 * @return array Array of the grouped opcodes for the generated diff. 
	 */ 
	public function getGroupedOpcodes() 
	{ 
		if(!is_null($this->groupedCodes)) { 
			return $this->groupedCodes; 
		} 
 
		require_once __DIR__ .'/Diff/SequenceMatcher.php'; 
		$sequenceMatcher = new nscanDiff_SequenceMatcher($this->a, $this->b, $this->options, null); 
		$this->groupedCodes = $sequenceMatcher->getGroupedOpcodes($this->options['context']); 
		return $this->groupedCodes; 
	} 
}