1 <?php

     2 /**

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

     4  * uses the xdiff PECL package (http://pecl.php.net/package/xdiff) to compute

     5  * the differences between the two input arrays.

     6  *

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

     8  * @package Text_Diff

     9  *

    10  * @access private

    11  */

    12 class Text_Diff_Engine_xdiff {

    13 

    14     function diff($from_lines, $to_lines)

    15     {

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

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

    18 

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

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

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

    22 

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

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

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

    26 

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

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

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

    30          *

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

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

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

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

    35         $edits = array();

    36         foreach ($diff as $line) {

    37             switch ($line[0]) {

    38             case ' ':

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

    40                 break;

    41 

    42             case '+':

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

    44                 break;

    45 

    46             case '-':

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

    48                 break;

    49             }

    50         }

    51 

    52         return $edits;

    53     }

    54 

    55 }