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<?php
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/**
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* Class used internally by Diff to actually compute the diffs. This class
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* uses the xdiff PECL package (http://pecl.php.net/package/xdiff) to compute
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* the differences between the two input arrays.
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*
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* @author Jon Parise <jon@horde.org>
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* @package Text_Diff
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*
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* @access private
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*/
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class Text_Diff_Engine_xdiff {
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function diff($from_lines, $to_lines)
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{
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array_walk($from_lines, array('Text_Diff', 'trimNewlines'));
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array_walk($to_lines, array('Text_Diff', 'trimNewlines'));
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/* Convert the two input arrays into strings for xdiff processing. */
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$from_string = implode("\n", $from_lines);
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$to_string = implode("\n", $to_lines);
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/* Diff the two strings and convert the result to an array. */
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$diff = xdiff_string_diff($from_string, $to_string, count($to_lines));
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$diff = explode("\n", $diff);
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/* Walk through the diff one line at a time. We build the $edits
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* array of diff operations by reading the first character of the
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* xdiff output (which is in the "unified diff" format).
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*
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* Note that we don't have enough information to detect "changed"
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* lines using this approach, so we can't add Text_Diff_Op_changed
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* instances to the $edits array. The result is still perfectly
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* valid, albeit a little less descriptive and efficient. */
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$edits = array();
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foreach ($diff as $line) {
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switch ($line[0]) {
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case ' ':
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$edits[] = &new Text_Diff_Op_copy(array(substr($line, 1)));
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break;
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case '+':
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$edits[] = &new Text_Diff_Op_add(array(substr($line, 1)));
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break;
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case '-':
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$edits[] = &new Text_Diff_Op_delete(array(substr($line, 1)));
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break;
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}
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}
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return $edits;
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}
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}