DiffEngine.php in Diff 7.2
Same filename and directory in other branches
A PHP diff engine for phpwiki. (Taken from phpwiki-1.3.3)
Copyright (C) 2000, 2001 Geoffrey T. Dairiki <dairiki@dairiki.org> You may copy this code freely under the conditions of the GPL.
File
DiffEngine.phpView source
<?php
// $Id$
/**
* @file
* A PHP diff engine for phpwiki. (Taken from phpwiki-1.3.3)
*
* Copyright (C) 2000, 2001 Geoffrey T. Dairiki <dairiki@dairiki.org>
* You may copy this code freely under the conditions of the GPL.
*/
define('USE_ASSERTS', FALSE);
/**
* @todo document
* @private
* @subpackage DifferenceEngine
*/
class _DiffOp {
var $type;
var $orig;
var $closing;
function reverse() {
trigger_error('pure virtual', E_USER_ERROR);
}
function norig() {
return $this->orig ? sizeof($this->orig) : 0;
}
function nclosing() {
return $this->closing ? sizeof($this->closing) : 0;
}
}
/**
* @todo document
* @private
* @subpackage DifferenceEngine
*/
class _DiffOp_Copy extends _DiffOp {
var $type = 'copy';
function _DiffOp_Copy($orig, $closing = FALSE) {
if (!is_array($closing)) {
$closing = $orig;
}
$this->orig = $orig;
$this->closing = $closing;
}
function reverse() {
return new _DiffOp_Copy($this->closing, $this->orig);
}
}
/**
* @todo document
* @private
* @subpackage DifferenceEngine
*/
class _DiffOp_Delete extends _DiffOp {
var $type = 'delete';
function _DiffOp_Delete($lines) {
$this->orig = $lines;
$this->closing = FALSE;
}
function reverse() {
return new _DiffOp_Add($this->orig);
}
}
/**
* @todo document
* @private
* @subpackage DifferenceEngine
*/
class _DiffOp_Add extends _DiffOp {
var $type = 'add';
function _DiffOp_Add($lines) {
$this->closing = $lines;
$this->orig = FALSE;
}
function reverse() {
return new _DiffOp_Delete($this->closing);
}
}
/**
* @todo document
* @private
* @subpackage DifferenceEngine
*/
class _DiffOp_Change extends _DiffOp {
var $type = 'change';
function _DiffOp_Change($orig, $closing) {
$this->orig = $orig;
$this->closing = $closing;
}
function reverse() {
return new _DiffOp_Change($this->closing, $this->orig);
}
}
/**
* Class used internally by Diff to actually compute the diffs.
*
* The algorithm used here is mostly lifted from the perl module
* Algorithm::Diff (version 1.06) by Ned Konz, which is available at:
* http://www.perl.com/CPAN/authors/id/N/NE/NEDKONZ/Algorithm-Diff-1.06.zip
*
* More ideas are taken from:
* http://www.ics.uci.edu/~eppstein/161/960229.html
*
* Some ideas are (and a bit of code) are from from analyze.c, from GNU
* diffutils-2.7, which can be found at:
* ftp://gnudist.gnu.org/pub/gnu/diffutils/diffutils-2.7.tar.gz
*
* closingly, some ideas (subdivision by NCHUNKS > 2, and some optimizations)
* are my own.
*
* Line length limits for robustness added by Tim Starling, 2005-08-31
*
* @author Geoffrey T. Dairiki, Tim Starling
* @private
* @subpackage DifferenceEngine
*/
class _DiffEngine {
function MAX_XREF_LENGTH() {
return 10000;
}
function diff($from_lines, $to_lines) {
$n_from = sizeof($from_lines);
$n_to = sizeof($to_lines);
$this->xchanged = $this->ychanged = array();
$this->xv = $this->yv = array();
$this->xind = $this->yind = array();
unset($this->seq);
unset($this->in_seq);
unset($this->lcs);
// Skip leading common lines.
for ($skip = 0; $skip < $n_from && $skip < $n_to; $skip++) {
if ($from_lines[$skip] !== $to_lines[$skip]) {
break;
}
$this->xchanged[$skip] = $this->ychanged[$skip] = FALSE;
}
// Skip trailing common lines.
$xi = $n_from;
$yi = $n_to;
for ($endskip = 0; --$xi > $skip && --$yi > $skip; $endskip++) {
if ($from_lines[$xi] !== $to_lines[$yi]) {
break;
}
$this->xchanged[$xi] = $this->ychanged[$yi] = FALSE;
}
// Ignore lines which do not exist in both files.
for ($xi = $skip; $xi < $n_from - $endskip; $xi++) {
$xhash[$this
->_line_hash($from_lines[$xi])] = 1;
}
for ($yi = $skip; $yi < $n_to - $endskip; $yi++) {
$line = $to_lines[$yi];
if ($this->ychanged[$yi] = empty($xhash[$this
->_line_hash($line)])) {
continue;
}
$yhash[$this
->_line_hash($line)] = 1;
$this->yv[] = $line;
$this->yind[] = $yi;
}
for ($xi = $skip; $xi < $n_from - $endskip; $xi++) {
$line = $from_lines[$xi];
if ($this->xchanged[$xi] = empty($yhash[$this
->_line_hash($line)])) {
continue;
}
$this->xv[] = $line;
$this->xind[] = $xi;
}
// Find the LCS.
$this
->_compareseq(0, sizeof($this->xv), 0, sizeof($this->yv));
// Merge edits when possible
$this
->_shift_boundaries($from_lines, $this->xchanged, $this->ychanged);
$this
->_shift_boundaries($to_lines, $this->ychanged, $this->xchanged);
// Compute the edit operations.
$edits = array();
$xi = $yi = 0;
while ($xi < $n_from || $yi < $n_to) {
USE_ASSERTS && assert($yi < $n_to || $this->xchanged[$xi]);
USE_ASSERTS && assert($xi < $n_from || $this->ychanged[$yi]);
// Skip matching "snake".
$copy = array();
while ($xi < $n_from && $yi < $n_to && !$this->xchanged[$xi] && !$this->ychanged[$yi]) {
$copy[] = $from_lines[$xi++];
++$yi;
}
if ($copy) {
$edits[] = new _DiffOp_Copy($copy);
}
// Find deletes & adds.
$delete = array();
while ($xi < $n_from && $this->xchanged[$xi]) {
$delete[] = $from_lines[$xi++];
}
$add = array();
while ($yi < $n_to && $this->ychanged[$yi]) {
$add[] = $to_lines[$yi++];
}
if ($delete && $add) {
$edits[] = new _DiffOp_Change($delete, $add);
}
elseif ($delete) {
$edits[] = new _DiffOp_Delete($delete);
}
elseif ($add) {
$edits[] = new _DiffOp_Add($add);
}
}
return $edits;
}
/**
* Returns the whole line if it's small enough, or the MD5 hash otherwise.
*/
function _line_hash($line) {
if (drupal_strlen($line) > $this
->MAX_XREF_LENGTH()) {
return md5($line);
}
else {
return $line;
}
}
/**
* Divide the Largest Common Subsequence (LCS) of the sequences
* [XOFF, XLIM) and [YOFF, YLIM) into NCHUNKS approximately equally
* sized segments.
*
* Returns (LCS, PTS). LCS is the length of the LCS. PTS is an
* array of NCHUNKS+1 (X, Y) indexes giving the diving points between
* sub sequences. The first sub-sequence is contained in [X0, X1),
* [Y0, Y1), the second in [X1, X2), [Y1, Y2) and so on. Note
* that (X0, Y0) == (XOFF, YOFF) and
* (X[NCHUNKS], Y[NCHUNKS]) == (XLIM, YLIM).
*
* This function assumes that the first lines of the specified portions
* of the two files do not match, and likewise that the last lines do not
* match. The caller must trim matching lines from the beginning and end
* of the portions it is going to specify.
*/
function _diag($xoff, $xlim, $yoff, $ylim, $nchunks) {
$flip = FALSE;
if ($xlim - $xoff > $ylim - $yoff) {
// Things seems faster (I'm not sure I understand why)
// when the shortest sequence in X.
$flip = TRUE;
list($xoff, $xlim, $yoff, $ylim) = array(
$yoff,
$ylim,
$xoff,
$xlim,
);
}
if ($flip) {
for ($i = $ylim - 1; $i >= $yoff; $i--) {
$ymatches[$this->xv[$i]][] = $i;
}
}
else {
for ($i = $ylim - 1; $i >= $yoff; $i--) {
$ymatches[$this->yv[$i]][] = $i;
}
}
$this->lcs = 0;
$this->seq[0] = $yoff - 1;
$this->in_seq = array();
$ymids[0] = array();
$numer = $xlim - $xoff + $nchunks - 1;
$x = $xoff;
for ($chunk = 0; $chunk < $nchunks; $chunk++) {
if ($chunk > 0) {
for ($i = 0; $i <= $this->lcs; $i++) {
$ymids[$i][$chunk - 1] = $this->seq[$i];
}
}
$x1 = $xoff + (int) (($numer + ($xlim - $xoff) * $chunk) / $nchunks);
for (; $x < $x1; $x++) {
$line = $flip ? $this->yv[$x] : $this->xv[$x];
if (empty($ymatches[$line])) {
continue;
}
$matches = $ymatches[$line];
reset($matches);
while (list($junk, $y) = each($matches)) {
if (empty($this->in_seq[$y])) {
$k = $this
->_lcs_pos($y);
USE_ASSERTS && assert($k > 0);
$ymids[$k] = $ymids[$k - 1];
break;
}
}
while (list($junk, $y) = each($matches)) {
if ($y > $this->seq[$k - 1]) {
USE_ASSERTS && assert($y < $this->seq[$k]);
// Optimization: this is a common case:
// next match is just replacing previous match.
$this->in_seq[$this->seq[$k]] = FALSE;
$this->seq[$k] = $y;
$this->in_seq[$y] = 1;
}
elseif (empty($this->in_seq[$y])) {
$k = $this
->_lcs_pos($y);
USE_ASSERTS && assert($k > 0);
$ymids[$k] = $ymids[$k - 1];
}
}
}
}
$seps[] = $flip ? array(
$yoff,
$xoff,
) : array(
$xoff,
$yoff,
);
$ymid = $ymids[$this->lcs];
for ($n = 0; $n < $nchunks - 1; $n++) {
$x1 = $xoff + (int) (($numer + ($xlim - $xoff) * $n) / $nchunks);
$y1 = $ymid[$n] + 1;
$seps[] = $flip ? array(
$y1,
$x1,
) : array(
$x1,
$y1,
);
}
$seps[] = $flip ? array(
$ylim,
$xlim,
) : array(
$xlim,
$ylim,
);
return array(
$this->lcs,
$seps,
);
}
function _lcs_pos($ypos) {
$end = $this->lcs;
if ($end == 0 || $ypos > $this->seq[$end]) {
$this->seq[++$this->lcs] = $ypos;
$this->in_seq[$ypos] = 1;
return $this->lcs;
}
$beg = 1;
while ($beg < $end) {
$mid = (int) (($beg + $end) / 2);
if ($ypos > $this->seq[$mid]) {
$beg = $mid + 1;
}
else {
$end = $mid;
}
}
USE_ASSERTS && assert($ypos != $this->seq[$end]);
$this->in_seq[$this->seq[$end]] = FALSE;
$this->seq[$end] = $ypos;
$this->in_seq[$ypos] = 1;
return $end;
}
/**
* Find LCS of two sequences.
*
* The results are recorded in the vectors $this->{x,y}changed[], by
* storing a 1 in the element for each line that is an insertion
* or deletion (ie. is not in the LCS).
*
* The subsequence of file 0 is [XOFF, XLIM) and likewise for file 1.
*
* Note that XLIM, YLIM are exclusive bounds.
* All line numbers are origin-0 and discarded lines are not counted.
*/
function _compareseq($xoff, $xlim, $yoff, $ylim) {
// Slide down the bottom initial diagonal.
while ($xoff < $xlim && $yoff < $ylim && $this->xv[$xoff] == $this->yv[$yoff]) {
++$xoff;
++$yoff;
}
// Slide up the top initial diagonal.
while ($xlim > $xoff && $ylim > $yoff && $this->xv[$xlim - 1] == $this->yv[$ylim - 1]) {
--$xlim;
--$ylim;
}
if ($xoff == $xlim || $yoff == $ylim) {
$lcs = 0;
}
else {
// This is ad hoc but seems to work well.
//$nchunks = sqrt(min($xlim - $xoff, $ylim - $yoff) / 2.5);
//$nchunks = max(2, min(8, (int)$nchunks));
$nchunks = min(7, $xlim - $xoff, $ylim - $yoff) + 1;
list($lcs, $seps) = $this
->_diag($xoff, $xlim, $yoff, $ylim, $nchunks);
}
if ($lcs == 0) {
// X and Y sequences have no common subsequence:
// mark all changed.
while ($yoff < $ylim) {
$this->ychanged[$this->yind[$yoff++]] = 1;
}
while ($xoff < $xlim) {
$this->xchanged[$this->xind[$xoff++]] = 1;
}
}
else {
// Use the partitions to split this problem into subproblems.
reset($seps);
$pt1 = $seps[0];
while ($pt2 = next($seps)) {
$this
->_compareseq($pt1[0], $pt2[0], $pt1[1], $pt2[1]);
$pt1 = $pt2;
}
}
}
/**
* Adjust inserts/deletes of identical lines to join changes
* as much as possible.
*
* We do something when a run of changed lines include a
* line at one end and has an excluded, identical line at the other.
* We are free to choose which identical line is included.
* `compareseq' usually chooses the one at the beginning,
* but usually it is cleaner to consider the following identical line
* to be the "change".
*
* This is extracted verbatim from analyze.c (GNU diffutils-2.7).
*/
function _shift_boundaries($lines, &$changed, $other_changed) {
$i = 0;
$j = 0;
USE_ASSERTS && assert('sizeof($lines) == sizeof($changed)');
$len = sizeof($lines);
$other_len = sizeof($other_changed);
while (1) {
/*
* Scan forwards to find beginning of another run of changes.
* Also keep track of the corresponding point in the other file.
*
* Throughout this code, $i and $j are adjusted together so that
* the first $i elements of $changed and the first $j elements
* of $other_changed both contain the same number of zeros
* (unchanged lines).
* Furthermore, $j is always kept so that $j == $other_len or
* $other_changed[$j] == FALSE.
*/
while ($j < $other_len && $other_changed[$j]) {
$j++;
}
while ($i < $len && !$changed[$i]) {
USE_ASSERTS && assert('$j < $other_len && ! $other_changed[$j]');
$i++;
$j++;
while ($j < $other_len && $other_changed[$j]) {
$j++;
}
}
if ($i == $len) {
break;
}
$start = $i;
// Find the end of this run of changes.
while (++$i < $len && $changed[$i]) {
continue;
}
do {
/*
* Record the length of this run of changes, so that
* we can later determine whether the run has grown.
*/
$runlength = $i - $start;
/*
* Move the changed region back, so long as the
* previous unchanged line matches the last changed one.
* This merges with previous changed regions.
*/
while ($start > 0 && $lines[$start - 1] == $lines[$i - 1]) {
$changed[--$start] = 1;
$changed[--$i] = FALSE;
while ($start > 0 && $changed[$start - 1]) {
$start--;
}
USE_ASSERTS && assert('$j > 0');
while ($other_changed[--$j]) {
continue;
}
USE_ASSERTS && assert('$j >= 0 && !$other_changed[$j]');
}
/*
* Set CORRESPONDING to the end of the changed run, at the last
* point where it corresponds to a changed run in the other file.
* CORRESPONDING == LEN means no such point has been found.
*/
$corresponding = $j < $other_len ? $i : $len;
/*
* Move the changed region forward, so long as the
* first changed line matches the following unchanged one.
* This merges with following changed regions.
* Do this second, so that if there are no merges,
* the changed region is moved forward as far as possible.
*/
while ($i < $len && $lines[$start] == $lines[$i]) {
$changed[$start++] = FALSE;
$changed[$i++] = 1;
while ($i < $len && $changed[$i]) {
$i++;
}
USE_ASSERTS && assert('$j < $other_len && ! $other_changed[$j]');
$j++;
if ($j < $other_len && $other_changed[$j]) {
$corresponding = $i;
while ($j < $other_len && $other_changed[$j]) {
$j++;
}
}
}
} while ($runlength != $i - $start);
/*
* If possible, move the fully-merged run of changes
* back to a corresponding run in the other file.
*/
while ($corresponding < $i) {
$changed[--$start] = 1;
$changed[--$i] = 0;
USE_ASSERTS && assert('$j > 0');
while ($other_changed[--$j]) {
continue;
}
USE_ASSERTS && assert('$j >= 0 && !$other_changed[$j]');
}
}
}
}
/**
* Class representing a 'diff' between two sequences of strings.
* @todo document
* @private
* @subpackage DifferenceEngine
*/
class Diff {
var $edits;
/**
* Constructor.
* Computes diff between sequences of strings.
*
* @param $from_lines array An array of strings.
* (Typically these are lines from a file.)
* @param $to_lines array An array of strings.
*/
function Diff($from_lines, $to_lines) {
$eng = new _DiffEngine();
$this->edits = $eng
->diff($from_lines, $to_lines);
//$this->_check($from_lines, $to_lines);
}
/**
* Compute reversed Diff.
*
* SYNOPSIS:
*
* $diff = new Diff($lines1, $lines2);
* $rev = $diff->reverse();
* @return object A Diff object representing the inverse of the
* original diff.
*/
function reverse() {
$rev = $this;
$rev->edits = array();
foreach ($this->edits as $edit) {
$rev->edits[] = $edit
->reverse();
}
return $rev;
}
/**
* Check for empty diff.
*
* @return bool True iff two sequences were identical.
*/
function isEmpty() {
foreach ($this->edits as $edit) {
if ($edit->type != 'copy') {
return FALSE;
}
}
return TRUE;
}
/**
* Compute the length of the Longest Common Subsequence (LCS).
*
* This is mostly for diagnostic purposed.
*
* @return int The length of the LCS.
*/
function lcs() {
$lcs = 0;
foreach ($this->edits as $edit) {
if ($edit->type == 'copy') {
$lcs += sizeof($edit->orig);
}
}
return $lcs;
}
/**
* Get the original set of lines.
*
* This reconstructs the $from_lines parameter passed to the
* constructor.
*
* @return array The original sequence of strings.
*/
function orig() {
$lines = array();
foreach ($this->edits as $edit) {
if ($edit->orig) {
array_splice($lines, sizeof($lines), 0, $edit->orig);
}
}
return $lines;
}
/**
* Get the closing set of lines.
*
* This reconstructs the $to_lines parameter passed to the
* constructor.
*
* @return array The sequence of strings.
*/
function closing() {
$lines = array();
foreach ($this->edits as $edit) {
if ($edit->closing) {
array_splice($lines, sizeof($lines), 0, $edit->closing);
}
}
return $lines;
}
/**
* Check a Diff for validity.
*
* This is here only for debugging purposes.
*/
function _check($from_lines, $to_lines) {
if (serialize($from_lines) != serialize($this
->orig())) {
trigger_error("Reconstructed original doesn't match", E_USER_ERROR);
}
if (serialize($to_lines) != serialize($this
->closing())) {
trigger_error("Reconstructed closing doesn't match", E_USER_ERROR);
}
$rev = $this
->reverse();
if (serialize($to_lines) != serialize($rev
->orig())) {
trigger_error("Reversed original doesn't match", E_USER_ERROR);
}
if (serialize($from_lines) != serialize($rev
->closing())) {
trigger_error("Reversed closing doesn't match", E_USER_ERROR);
}
$prevtype = 'none';
foreach ($this->edits as $edit) {
if ($prevtype == $edit->type) {
trigger_error("Edit sequence is non-optimal", E_USER_ERROR);
}
$prevtype = $edit->type;
}
$lcs = $this
->lcs();
trigger_error('Diff okay: LCS = ' . $lcs, E_USER_NOTICE);
}
}
/**
* FIXME: bad name.
* @todo document
* @private
* @subpackage DifferenceEngine
*/
class MappedDiff extends Diff {
/**
* Constructor.
*
* Computes diff between sequences of strings.
*
* This can be used to compute things like
* case-insensitve diffs, or diffs which ignore
* changes in white-space.
*
* @param $from_lines array An array of strings.
* (Typically these are lines from a file.)
*
* @param $to_lines array An array of strings.
*
* @param $mapped_from_lines array This array should
* have the same size number of elements as $from_lines.
* The elements in $mapped_from_lines and
* $mapped_to_lines are what is actually compared
* when computing the diff.
*
* @param $mapped_to_lines array This array should
* have the same number of elements as $to_lines.
*/
function MappedDiff($from_lines, $to_lines, $mapped_from_lines, $mapped_to_lines) {
assert(sizeof($from_lines) == sizeof($mapped_from_lines));
assert(sizeof($to_lines) == sizeof($mapped_to_lines));
$this
->Diff($mapped_from_lines, $mapped_to_lines);
$xi = $yi = 0;
for ($i = 0; $i < sizeof($this->edits); $i++) {
$orig =& $this->edits[$i]->orig;
if (is_array($orig)) {
$orig = array_slice($from_lines, $xi, sizeof($orig));
$xi += sizeof($orig);
}
$closing =& $this->edits[$i]->closing;
if (is_array($closing)) {
$closing = array_slice($to_lines, $yi, sizeof($closing));
$yi += sizeof($closing);
}
}
}
}
/**
* A class to format Diffs
*
* This class formats the diff in classic diff format.
* It is intended that this class be customized via inheritance,
* to obtain fancier outputs.
* @todo document
* @private
* @subpackage DifferenceEngine
*/
class DiffFormatter {
/**
* Should a block header be shown?
*/
var $show_header = TRUE;
/**
* Number of leading context "lines" to preserve.
*
* This should be left at zero for this class, but subclasses
* may want to set this to other values.
*/
var $leading_context_lines = 0;
/**
* Number of trailing context "lines" to preserve.
*
* This should be left at zero for this class, but subclasses
* may want to set this to other values.
*/
var $trailing_context_lines = 0;
/**
* Format a diff.
*
* @param $diff object A Diff object.
* @return string The formatted output.
*/
function format($diff) {
$xi = $yi = 1;
$block = FALSE;
$context = array();
$nlead = $this->leading_context_lines;
$ntrail = $this->trailing_context_lines;
$this
->_start_diff();
foreach ($diff->edits as $edit) {
if ($edit->type == 'copy') {
if (is_array($block)) {
if (sizeof($edit->orig) <= $nlead + $ntrail) {
$block[] = $edit;
}
else {
if ($ntrail) {
$context = array_slice($edit->orig, 0, $ntrail);
$block[] = new _DiffOp_Copy($context);
}
$this
->_block($x0, $ntrail + $xi - $x0, $y0, $ntrail + $yi - $y0, $block);
$block = FALSE;
}
}
$context = $edit->orig;
}
else {
if (!is_array($block)) {
$context = array_slice($context, sizeof($context) - $nlead);
$x0 = $xi - sizeof($context);
$y0 = $yi - sizeof($context);
$block = array();
if ($context) {
$block[] = new _DiffOp_Copy($context);
}
}
$block[] = $edit;
}
if ($edit->orig) {
$xi += sizeof($edit->orig);
}
if ($edit->closing) {
$yi += sizeof($edit->closing);
}
}
if (is_array($block)) {
$this
->_block($x0, $xi - $x0, $y0, $yi - $y0, $block);
}
$end = $this
->_end_diff();
return $end;
}
function _block($xbeg, $xlen, $ybeg, $ylen, &$edits) {
$this
->_start_block($this
->_block_header($xbeg, $xlen, $ybeg, $ylen));
foreach ($edits as $edit) {
if ($edit->type == 'copy') {
$this
->_context($edit->orig);
}
elseif ($edit->type == 'add') {
$this
->_added($edit->closing);
}
elseif ($edit->type == 'delete') {
$this
->_deleted($edit->orig);
}
elseif ($edit->type == 'change') {
$this
->_changed($edit->orig, $edit->closing);
}
else {
trigger_error('Unknown edit type', E_USER_ERROR);
}
}
$this
->_end_block();
}
function _start_diff() {
ob_start();
}
function _end_diff() {
$val = ob_get_contents();
ob_end_clean();
return $val;
}
function _block_header($xbeg, $xlen, $ybeg, $ylen) {
if ($xlen > 1) {
$xbeg .= "," . ($xbeg + $xlen - 1);
}
if ($ylen > 1) {
$ybeg .= "," . ($ybeg + $ylen - 1);
}
return $xbeg . ($xlen ? $ylen ? 'c' : 'd' : 'a') . $ybeg;
}
function _start_block($header) {
if ($this->show_header) {
echo $header . "\n";
}
}
function _end_block() {
}
function _lines($lines, $prefix = ' ') {
foreach ($lines as $line) {
echo "{$prefix} {$line}\n";
}
}
function _context($lines) {
$this
->_lines($lines);
}
function _added($lines) {
$this
->_lines($lines, '>');
}
function _deleted($lines) {
$this
->_lines($lines, '<');
}
function _changed($orig, $closing) {
$this
->_deleted($orig);
echo "---\n";
$this
->_added($closing);
}
}
/**
* Additions by Axel Boldt follow, partly taken from diff.php, phpwiki-1.3.3
*
*/
define('NBSP', ' ');
// iso-8859-x non-breaking space.
/**
* @todo document
* @private
* @subpackage DifferenceEngine
*/
class _HWLDF_WordAccumulator {
function _HWLDF_WordAccumulator() {
$this->_lines = array();
$this->_line = '';
$this->_group = '';
$this->_tag = '';
}
function _flushGroup($new_tag) {
if ($this->_group !== '') {
if ($this->_tag == 'mark') {
$this->_line .= '<span class="diffchange">' . check_plain($this->_group) . '</span>';
}
else {
$this->_line .= check_plain($this->_group);
}
}
$this->_group = '';
$this->_tag = $new_tag;
}
function _flushLine($new_tag) {
$this
->_flushGroup($new_tag);
if ($this->_line != '') {
array_push($this->_lines, $this->_line);
}
else {
// make empty lines visible by inserting an NBSP
array_push($this->_lines, NBSP);
}
$this->_line = '';
}
function addWords($words, $tag = '') {
if ($tag != $this->_tag) {
$this
->_flushGroup($tag);
}
foreach ($words as $word) {
// new-line should only come as first char of word.
if ($word == '') {
continue;
}
if ($word[0] == "\n") {
$this
->_flushLine($tag);
$word = drupal_substr($word, 1);
}
assert(!strstr($word, "\n"));
$this->_group .= $word;
}
}
function getLines() {
$this
->_flushLine('~done');
return $this->_lines;
}
}
/**
* @todo document
* @private
* @subpackage DifferenceEngine
*/
class WordLevelDiff extends MappedDiff {
function MAX_LINE_LENGTH() {
return 10000;
}
function WordLevelDiff($orig_lines, $closing_lines) {
list($orig_words, $orig_stripped) = $this
->_split($orig_lines);
list($closing_words, $closing_stripped) = $this
->_split($closing_lines);
$this
->MappedDiff($orig_words, $closing_words, $orig_stripped, $closing_stripped);
}
function _split($lines) {
$words = array();
$stripped = array();
$first = TRUE;
foreach ($lines as $line) {
// If the line is too long, just pretend the entire line is one big word
// This prevents resource exhaustion problems
if ($first) {
$first = FALSE;
}
else {
$words[] = "\n";
$stripped[] = "\n";
}
if (drupal_strlen($line) > $this
->MAX_LINE_LENGTH()) {
$words[] = $line;
$stripped[] = $line;
}
else {
if (preg_match_all('/ ( [^\\S\\n]+ | [0-9_A-Za-z\\x80-\\xff]+ | . ) (?: (?!< \\n) [^\\S\\n])? /xs', $line, $m)) {
$words = array_merge($words, $m[0]);
$stripped = array_merge($stripped, $m[1]);
}
}
}
return array(
$words,
$stripped,
);
}
function orig() {
$orig = new _HWLDF_WordAccumulator();
foreach ($this->edits as $edit) {
if ($edit->type == 'copy') {
$orig
->addWords($edit->orig);
}
elseif ($edit->orig) {
$orig
->addWords($edit->orig, 'mark');
}
}
$lines = $orig
->getLines();
return $lines;
}
function closing() {
$closing = new _HWLDF_WordAccumulator();
foreach ($this->edits as $edit) {
if ($edit->type == 'copy') {
$closing
->addWords($edit->closing);
}
elseif ($edit->closing) {
$closing
->addWords($edit->closing, 'mark');
}
}
$lines = $closing
->getLines();
return $lines;
}
}
/**
* Diff formatter which uses Drupal theme functions.
* @private
* @subpackage DifferenceEngine
*/
class DrupalDiffFormatter extends DiffFormatter {
var $rows;
function DrupalDiffFormatter() {
$this->leading_context_lines = 2;
$this->trailing_context_lines = 2;
}
function _start_diff() {
$this->rows = array();
}
function _end_diff() {
return $this->rows;
}
function _block_header($xbeg, $xlen, $ybeg, $ylen) {
return array(
array(
'data' => theme('diff_header_line', array(
'lineno' => $xbeg,
)),
'colspan' => 2,
),
array(
'data' => theme('diff_header_line', array(
'lineno' => $ybeg,
)),
'colspan' => 2,
),
);
}
function _start_block($header) {
if ($this->show_header) {
$this->rows[] = $header;
}
}
function _end_block() {
}
function _lines($lines, $prefix = ' ', $color = 'white') {
}
/**
* Note: you should HTML-escape parameter before calling this.
*/
function addedLine($line) {
return array(
'+',
array(
'data' => theme('diff_content_line', array(
'line' => $line,
)),
'class' => 'diff-addedline',
),
);
}
/**
* Note: you should HTML-escape parameter before calling this.
*/
function deletedLine($line) {
return array(
'-',
array(
'data' => theme('diff_content_line', array(
'line' => $line,
)),
'class' => 'diff-deletedline',
),
);
}
/**
* Note: you should HTML-escape parameter before calling this.
*/
function contextLine($line) {
return array(
' ',
array(
'data' => theme('diff_content_line', array(
'line' => $line,
)),
'class' => 'diff-context',
),
);
}
function emptyLine() {
return array(
' ',
theme('diff_empty_line', array(
'line' => ' ',
)),
);
}
function _added($lines) {
foreach ($lines as $line) {
$this->rows[] = array_merge($this
->emptyLine(), $this
->addedLine(check_plain($line)));
}
}
function _deleted($lines) {
foreach ($lines as $line) {
$this->rows[] = array_merge($this
->deletedLine(check_plain($line)), $this
->emptyLine());
}
}
function _context($lines) {
foreach ($lines as $line) {
$this->rows[] = array_merge($this
->contextLine(check_plain($line)), $this
->contextLine(check_plain($line)));
}
}
function _changed($orig, $closing) {
$diff = new WordLevelDiff($orig, $closing);
$del = $diff
->orig();
$add = $diff
->closing();
// Notice that WordLevelDiff returns HTML-escaped output.
// Hence, we will be calling addedLine/deletedLine without HTML-escaping.
while ($line = array_shift($del)) {
$aline = array_shift($add);
$this->rows[] = array_merge($this
->deletedLine($line), $this
->addedLine($aline));
}
foreach ($add as $line) {
// If any leftovers
$this->rows[] = array_merge($this
->emptyLine(), $this
->addedLine($line));
}
}
}
/**
* Drupal inline Diff formatter.
* @private
* @subpackage DifferenceEngine
*/
class DrupalDiffInline {
var $a;
var $b;
/**
* Constructor.
*/
function __construct($a, $b) {
$this->a = $a;
$this->b = $b;
}
/**
* Render differences inline using HTML markup.
*/
function render() {
$a = preg_split('/(<[^>]+?>| )/', $this->a, -1, PREG_SPLIT_DELIM_CAPTURE);
$b = preg_split('/(<[^>]+?>| )/', $this->b, -1, PREG_SPLIT_DELIM_CAPTURE);
$diff = new Diff($a, $b);
$diff->edits = $this
->process_edits($diff->edits);
// Assemble highlighted output
$output = '';
foreach ($diff->edits as $chunk) {
switch ($chunk->type) {
case 'copy':
$output .= implode('', $chunk->closing);
break;
case 'delete':
foreach ($chunk->orig as $i => $piece) {
if (strpos($piece, '<') === 0 && drupal_substr($piece, drupal_strlen($piece) - 1) === '>') {
$output .= $piece;
}
else {
$output .= theme('diff_inline_chunk', array(
'text' => $piece,
'type' => $chunk->type,
));
}
}
break;
default:
$chunk->closing = $this
->process_chunk($chunk->closing);
foreach ($chunk->closing as $i => $piece) {
if ($piece === ' ' || strpos($piece, '<') === 0 && drupal_substr($piece, drupal_strlen($piece) - 1) === '>' && drupal_strtolower(drupal_substr($piece, 1, 3)) != 'img') {
$output .= $piece;
}
else {
$output .= theme('diff_inline_chunk', array(
'text' => $piece,
'type' => $chunk->type,
));
}
}
break;
}
}
return $output;
}
/**
* Merge chunk segments between tag delimiters.
*/
function process_chunk($chunk) {
$processed = array();
$j = 0;
foreach ($chunk as $i => $piece) {
$next = isset($chunk[$i + 1]) ? $chunk[$i + 1] : NULL;
if (strpos($piece, '<') === 0 && drupal_substr($piece, drupal_strlen($piece) - 1) === '>') {
$processed[$j] = $piece;
$j++;
}
elseif (isset($next) && strpos($next, '<') === 0 && drupal_substr($next, drupal_strlen($next) - 1) === '>') {
$processed[$j] .= $piece;
$j++;
}
else {
$processed[$j] .= $piece;
}
}
return $processed;
}
/**
* Merge copy and equivalent edits into intelligible chunks.
*/
function process_edits($edits) {
$processed = array();
$current = array_shift($edits);
// Make two passes -- first merge space delimiter copies back into their originals.
while ($chunk = array_shift($edits)) {
if ($chunk->type == 'copy' && $chunk->orig === array(
' ',
)) {
$current->orig = array_merge((array) $current->orig, (array) $chunk->orig);
$current->closing = array_merge((array) $current->closing, (array) $chunk->closing);
}
else {
$processed[] = $current;
$current = $chunk;
}
}
$processed[] = $current;
// Initial setup
$edits = $processed;
$processed = array();
$current = array_shift($edits);
// Second, merge equivalent chunks into each other.
while ($chunk = array_shift($edits)) {
if ($current->type == $chunk->type) {
$current->orig = array_merge((array) $current->orig, (array) $chunk->orig);
$current->closing = array_merge((array) $current->closing, (array) $chunk->closing);
}
else {
$processed[] = $current;
$current = $chunk;
}
}
$processed[] = $current;
return $processed;
}
}Constants
Name |
Description |
|---|---|
| NBSP | Additions by Axel Boldt follow, partly taken from diff.php, phpwiki-1.3.3 |
| USE_ASSERTS | @file A PHP diff engine for phpwiki. (Taken from phpwiki-1.3.3) |
Classes
|
Name |
Description |
|---|---|
| Diff | Class representing a 'diff' between two sequences of strings. @todo document @private @subpackage DifferenceEngine |
| DiffFormatter | A class to format Diffs |
| DrupalDiffFormatter | Diff formatter which uses Drupal theme functions. @private @subpackage DifferenceEngine |
| DrupalDiffInline | Drupal inline Diff formatter. @private @subpackage DifferenceEngine |
| MappedDiff | FIXME: bad name. @todo document @private @subpackage DifferenceEngine |
| WordLevelDiff | @todo document @private @subpackage DifferenceEngine |
| _DiffEngine | Class used internally by Diff to actually compute the diffs. |
| _DiffOp | @todo document @private @subpackage DifferenceEngine |
| _DiffOp_Add | @todo document @private @subpackage DifferenceEngine |
| _DiffOp_Change | @todo document @private @subpackage DifferenceEngine |
| _DiffOp_Copy | @todo document @private @subpackage DifferenceEngine |
| _DiffOp_Delete | @todo document @private @subpackage DifferenceEngine |
| _HWLDF_WordAccumulator | @todo document @private @subpackage DifferenceEngine |