, and is used/adapted with his permission.
*
* Copyright 2004 Geoffrey T. Dairiki
* $diff = new Text_Diff($lines1, $lines2);
* $rev = $diff->reverse();
*
*
* @return Text_Diff A Diff object representing the inverse of the
* original diff. Note that we purposely don't return a
* reference here, since this essentially is a clone()
* method.
*/
function reverse()
{
if (version_compare(zend_version(), '2', '>')) {
$rev = clone($this);
} else {
$rev = $this;
}
$rev->_edits = array();
foreach ($this->_edits as $edit) {
$rev->_edits[] = $edit->reverse();
}
return $rev;
}
/**
* Checks for an empty diff.
*
* @return bool True if two sequences were identical.
*/
function isEmpty()
{
foreach ($this->_edits as $edit) {
if (!is_a($edit, 'Text_Diff_Op_copy')) {
return false;
}
}
return true;
}
/**
* Computes the length of the Longest Common Subsequence (LCS).
*
* This is mostly for diagnostic purposes.
*
* @return int The length of the LCS.
*/
function lcs()
{
$lcs = 0;
foreach ($this->_edits as $edit) {
if (is_a($edit, 'Text_Diff_Op_copy')) {
$lcs += count($edit->orig);
}
}
return $lcs;
}
/**
* Gets the original set of lines.
*
* This reconstructs the $from_lines parameter passed to the constructor.
*
* @return array The original sequence of strings.
*/
function getOriginal()
{
$lines = array();
foreach ($this->_edits as $edit) {
if ($edit->orig) {
array_splice($lines, count($lines), 0, $edit->orig);
}
}
return $lines;
}
/**
* Gets the final set of lines.
*
* This reconstructs the $to_lines parameter passed to the constructor.
*
* @return array The sequence of strings.
*/
function getFinal()
{
$lines = array();
foreach ($this->_edits as $edit) {
if ($edit->final) {
array_splice($lines, count($lines), 0, $edit->final);
}
}
return $lines;
}
/**
* Removes trailing newlines from a line of text. This is meant to be used
* with array_walk().
*
* @param string $line The line to trim.
* @param int $key The index of the line in the array. Not used.
*/
static function trimNewlines(&$line, $key)
{
$line = str_replace(array("\n", "\r"), '', $line);
}
/**
* Determines the location of the system temporary directory.
*
* @access protected
*
* @return string A directory name which can be used for temp files.
* Returns false if one could not be found.
*/
static function _getTempDir()
{
$tmp_locations = array('/tmp', '/var/tmp', 'c:\WUTemp', 'c:\temp',
'c:\windows\temp', 'c:\winnt\temp');
/* Try PHP's upload_tmp_dir directive. */
$tmp = ini_get('upload_tmp_dir');
/* Otherwise, try to determine the TMPDIR environment variable. */
if (!strlen($tmp)) {
$tmp = getenv('TMPDIR');
}
/* If we still cannot determine a value, then cycle through a list of
* preset possibilities. */
while (!strlen($tmp) && count($tmp_locations)) {
$tmp_check = array_shift($tmp_locations);
if (@is_dir($tmp_check)) {
$tmp = $tmp_check;
}
}
/* If it is still empty, we have failed, so return false; otherwise
* return the directory determined. */
return strlen($tmp) ? $tmp : false;
}
/**
* Checks a diff for validity.
*
* This is here only for debugging purposes.
*/
function _check($from_lines, $to_lines)
{
if (serialize($from_lines) != serialize($this->getOriginal())) {
throw new Text_Exception("Reconstructed original does not match");
}
if (serialize($to_lines) != serialize($this->getFinal())) {
throw new Text_Exception("Reconstructed final does not match");
}
$rev = $this->reverse();
if (serialize($to_lines) != serialize($rev->getOriginal())) {
throw new Text_Exception("Reversed original does not match");
}
if (serialize($from_lines) != serialize($rev->getFinal())) {
throw new Text_Exception("Reversed final does not match");
}
$prevtype = null;
foreach ($this->_edits as $edit) {
if ($prevtype !== null && $edit instanceof $prevtype) {
throw new Text_Exception("Edit sequence is non-optimal");
}
$prevtype = get_class($edit);
}
return true;
}
}
/**
* @package Text_Diff
* @author Geoffrey T. Dairiki