<?php
/**
* Parses unified or context diffs output from eg. the diff utility.
*
* Example:
* <code>
* $patch = file_get_contents('example.patch');
* $diff = &new Text_Diff('string', array($patch));
* $renderer = &new Text_Diff_Renderer_inline();
* echo $renderer->render($diff);
* </code>
*
* @author �rjan Persson <o@42mm.org>
* @copyright Copyright 2005 �rjan Persson
* @package Text_Diff
* @since 0.2.0
* @access private
*/
class Text_Diff_Engine_string {
/**
* Parses a unified or context diff.
*
* First param contains the whole diff and the second can be used to force
* a specific diff type. If the second parameter is 'autodetect', the
* diff will be examined to find out which type of diff this is.
*
* @param string $diff The diff content.
* @param string $mode The diff mode of the content in $diff. One of
* 'context', 'unified', or 'autodetect'.
*
* @return array List of all diff operations.
*/
function diff($diff, $mode = 'autodetect')
{
if ($mode != 'autodetect' && $mode != 'context' && $mode != 'unified') {
die_friendly('Text_Diff', '<p>Type of diff is unsupported</p>');
}
if ($mode == 'autodetect') {
$context = strpos($diff, '***');
$unified = strpos($diff, '---');
if ($context === $unified) {
die_friendly('Text_Diff', '<p>Type of diff could not be detected</p>');
} elseif ($context === false || $context === false) {
$mode = $context !== false ? 'context' : 'unified';
} else {
$mode = $context < $unified ? 'context' : 'unified';
}
}
// split by new line and remove the diff header
$diff = explode("\n", $diff);
array_shift($diff);
array_shift($diff);
if ($mode == 'context') {
return $this->parseContextDiff($diff);
} else {
return $this->parseUnifiedDiff($diff);
}
}
/**
* Parses an array containing the unified diff.
*
* @param array $diff Array of lines.
*
* @return array List of all diff operations.
*/
function parseUnifiedDiff($diff)
{
$edits = array();
$end = count($diff) - 1;
for ($i = 0; $i < $end;) {
$diff1 = array();
switch (substr($diff[$i], 0, 1)) {
case ' ':
do {
$diff1[] = substr($diff[$i], 1);
} while (++$i < $end && substr($diff[$i], 0, 1) == ' ');
$edits[] = &new Text_Diff_Op_copy($diff1);
break;
case '+':
// get all new lines
do {
$diff1[] = substr($diff[$i], 1);
} while (++$i < $end && substr($diff[$i], 0, 1) == '+');
$edits[] = &new Text_Diff_Op_add($diff1);
break;
case '-':
// get changed or removed lines
$diff2 = array();
do {
$diff1[] = substr($diff[$i], 1);
} while (++$i < $end && substr($diff[$i], 0, 1) == '-');
while ($i < $end && substr($diff[$i], 0, 1) == '+') {
$diff2[] = substr($diff[$i++], 1);
}
if (count($diff2) == 0) {
$edits[] = &new Text_Diff_Op_delete($diff1);
} else {
$edits[] = &new Text_Diff_Op_change($diff1, $diff2);
}
break;
default:
$i++;
break;
}
}
return $edits;
}
/**
* Parses an array containing the context diff.
*
* @param array $diff Array of lines.
*
* @return array List of all diff operations.
*/
function parseContextDiff(&$diff)
{
$edits = array();
$i = $max_i = $j = $max_j = 0;
$end = count($diff) - 1;
while ($i < $end && $j < $end) {
while ($i >= $max_i && $j >= $max_j) {
// find the boundaries of the diff output of the two files
for ($i = $j;
$i < $end && substr($diff[$i], 0, 3) == '***';
$i++);
for ($max_i = $i;
$max_i < $end && substr($diff[$max_i], 0, 3) != '---';
$max_i++);
for ($j = $max_i;
$j < $end && substr($diff[$j], 0, 3) == '---';
$j++);
for ($max_j = $j;
$max_j < $end && substr($diff[$max_j], 0, 3) != '***';
$max_j++);
}
// find what hasn't been changed
$array = array();
while ($i < $max_i &&
$j < $max_j &&
strcmp($diff[$i], $diff[$j]) == 0) {
$array[] = substr($diff[$i], 2);
$i++;
$j++;
}
while ($i < $max_i && ($max_j-$j) <= 1) {
if ($diff[$i] != '' && substr($diff[$i], 0, 1) != ' ') {
break;
}
$array[] = substr($diff[$i++], 2);
}
while ($j < $max_j && ($max_i-$i) <= 1) {
if ($diff[$j] != '' && substr($diff[$j], 0, 1) != ' ') {
break;
}
$array[] = substr($diff[$j++], 2);
}
if (count($array) > 0) {
$edits[] = &new Text_Diff_Op_copy($array);
}
if ($i < $max_i) {
$diff1 = array();
switch (substr($diff[$i], 0, 1)) {
case '!':
$diff2 = array();
do {
$diff1[] = substr($diff[$i], 2);
if ($j < $max_j && substr($diff[$j], 0, 1) == '!') {
$diff2[] = substr($diff[$j++], 2);
}
} while (++$i < $max_i && substr($diff[$i], 0, 1) == '!');
$edits[] = &new Text_Diff_Op_change($diff1, $diff2);
break;
case '+':
do {
$diff1[] = substr($diff[$i], 2);
} while (++$i < $max_i && substr($diff[$i], 0, 1) == '+');
$edits[] = &new Text_Diff_Op_add($diff1);
break;
case '-':
do {
$diff1[] = substr($diff[$i], 2);
} while (++$i < $max_i && substr($diff[$i], 0, 1) == '-');
$edits[] = &new Text_Diff_Op_delete($diff1);
break;
}
}
if ($j < $max_j) {
$diff2 = array();
switch (substr($diff[$j], 0, 1)) {
case '+':
do {
$diff2[] = substr($diff[$j++], 2);
} while ($j < $max_j && substr($diff[$j], 0, 1) == '+');
$edits[] = &new Text_Diff_Op_add($diff2);
break;
case '-':
do {
$diff2[] = substr($diff[$j++], 2);
} while ($j < $max_j && substr($diff[$j], 0, 1) == '-');
$edits[] = &new Text_Diff_Op_delete($diff2);
break;
}
}
}
return $edits;
}
}