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* Class used internally by Diff to actually compute the diffs.
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* This class uses the xdiff PECL package (http://pecl.php.net/package/xdiff)
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* to compute the differences between the two input arrays.
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* Copyright 2004-2010 The Horde Project (http://www.horde.org/)
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* See the enclosed file COPYING for license information (LGPL). If you did
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* not receive this file, see http://opensource.org/licenses/lgpl-license.php.
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* @author Jon Parise <jon@horde.org>
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class Text_Diff_Engine_xdiff {
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function diff($from_lines, $to_lines)
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array_walk($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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* 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 $edits array. The result is still perfectly
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* valid, albeit a little less descriptive and efficient. */
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foreach ($diff as $line) {
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$edits[] = new Text_Diff_Op_copy(array(substr($line, 1)));
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$edits[] = new Text_Diff_Op_add(array(substr($line, 1)));
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$edits[] = new Text_Diff_Op_delete(array(substr($line, 1)));