1 <?php

     2 /**

     3  * Class used internally by Diff to actually compute the diffs.

     4  *

     5  * This class uses the xdiff PECL package (http://pecl.php.net/package/xdiff)

     6  * to compute the differences between the two input arrays.

     7  *

     8  * $Horde: framework/Text_Diff/Diff/Engine/xdiff.php,v 1.6 2008/01/04 10:07:50 jan Exp $

     9  *

    10  * Copyright 2004-2008 The Horde Project (http://www.horde.org/)

    11  *

    12  * See the enclosed file COPYING for license information (LGPL). If you did

    13  * not receive this file, see http://opensource.org/licenses/lgpl-license.php.

    14  *

    15  * @author  Jon Parise <jon@horde.org>

    16  * @package Text_Diff

    17  */

    18 class Text_Diff_Engine_xdiff {

    19 

    20     /**

    21      */

    22     function diff($from_lines, $to_lines)

    23     {

    24         array_walk($from_lines, array('Text_Diff', 'trimNewlines'));

    25         array_walk($to_lines, array('Text_Diff', 'trimNewlines'));

    26 

    27         /* Convert the two input arrays into strings for xdiff processing. */

    28         $from_string = implode("\n", $from_lines);

    29         $to_string = implode("\n", $to_lines);

    30 

    31         /* Diff the two strings and convert the result to an array. */

    32         $diff = xdiff_string_diff($from_string, $to_string, count($to_lines));

    33         $diff = explode("\n", $diff);

    34 

    35         /* Walk through the diff one line at a time.  We build the $edits

    36          * array of diff operations by reading the first character of the

    37          * xdiff output (which is in the "unified diff" format).

    38          *

    39          * Note that we don't have enough information to detect "changed"

    40          * lines using this approach, so we can't add Text_Diff_Op_changed

    41          * instances to the $edits array.  The result is still perfectly

    42          * valid, albeit a little less descriptive and efficient. */

    43         $edits = array();

    44         foreach ($diff as $line) {

    45             switch ($line[0]) {

    46             case ' ':

    47                 $edits[] = &new Text_Diff_Op_copy(array(substr($line, 1)));

    48                 break;

    49 

    50             case '+':

    51                 $edits[] = &new Text_Diff_Op_add(array(substr($line, 1)));

    52                 break;

    53 

    54             case '-':

    55                 $edits[] = &new Text_Diff_Op_delete(array(substr($line, 1)));

    56                 break;

    57             }

    58         }

    59 

    60         return $edits;

    61     }

    62 

    63 }