--- a/includes/diffengine/Engine/native.php Sun Mar 28 21:49:26 2010 -0400
+++ b/includes/diffengine/Engine/native.php Sun Mar 28 23:10:46 2010 -0400
@@ -27,409 +27,409 @@
*/
class Text_Diff_Engine_native {
- function diff($from_lines, $to_lines)
- {
- array_walk($from_lines, array('Text_Diff', 'trimNewlines'));
- array_walk($to_lines, array('Text_Diff', 'trimNewlines'));
+ function diff($from_lines, $to_lines)
+ {
+ array_walk($from_lines, array('Text_Diff', 'trimNewlines'));
+ array_walk($to_lines, array('Text_Diff', 'trimNewlines'));
- $n_from = count($from_lines);
- $n_to = count($to_lines);
+ $n_from = count($from_lines);
+ $n_to = count($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);
+ $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 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;
- }
+ // 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++) {
- $xhash[$from_lines[$xi]] = 1;
- }
- for ($yi = $skip; $yi < $n_to - $endskip; $yi++) {
- $line = $to_lines[$yi];
- if (($this->ychanged[$yi] = empty($xhash[$line]))) {
- continue;
- }
- $yhash[$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($yhash[$line]))) {
- continue;
- }
- $this->xv[] = $line;
- $this->xind[] = $xi;
- }
+ // Ignore lines which do not exist in both files.
+ for ($xi = $skip; $xi < $n_from - $endskip; $xi++) {
+ $xhash[$from_lines[$xi]] = 1;
+ }
+ for ($yi = $skip; $yi < $n_to - $endskip; $yi++) {
+ $line = $to_lines[$yi];
+ if (($this->ychanged[$yi] = empty($xhash[$line]))) {
+ continue;
+ }
+ $yhash[$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($yhash[$line]))) {
+ continue;
+ }
+ $this->xv[] = $line;
+ $this->xind[] = $xi;
+ }
- // Find the LCS.
- $this->_compareseq(0, count($this->xv), 0, count($this->yv));
+ // Find the LCS.
+ $this->_compareseq(0, count($this->xv), 0, count($this->yv));
- // Merge edits when possible.
- $this->_shiftBoundaries($from_lines, $this->xchanged, $this->ychanged);
- $this->_shiftBoundaries($to_lines, $this->ychanged, $this->xchanged);
+ // Merge edits when possible.
+ $this->_shiftBoundaries($from_lines, $this->xchanged, $this->ychanged);
+ $this->_shiftBoundaries($to_lines, $this->ychanged, $this->xchanged);
- // Compute the edit operations.
- $edits = array();
- $xi = $yi = 0;
- while ($xi < $n_from || $yi < $n_to) {
- assert($yi < $n_to || $this->xchanged[$xi]);
- assert($xi < $n_from || $this->ychanged[$yi]);
+ // Compute the edit operations.
+ $edits = array();
+ $xi = $yi = 0;
+ while ($xi < $n_from || $yi < $n_to) {
+ assert($yi < $n_to || $this->xchanged[$xi]);
+ 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) {
- $edits[] = &new Text_Diff_Op_copy($copy);
- }
+ // 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) {
+ $edits[] = &new Text_Diff_Op_copy($copy);
+ }
- // Find deletes & adds.
- $delete = array();
- while ($xi < $n_from && $this->xchanged[$xi]) {
- $delete[] = $from_lines[$xi++];
- }
+ // 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++];
- }
+ $add = array();
+ while ($yi < $n_to && $this->ychanged[$yi]) {
+ $add[] = $to_lines[$yi++];
+ }
- if ($delete && $add) {
- $edits[] = &new Text_Diff_Op_change($delete, $add);
- } elseif ($delete) {
- $edits[] = &new Text_Diff_Op_delete($delete);
- } elseif ($add) {
- $edits[] = &new Text_Diff_Op_add($add);
- }
- }
+ if ($delete && $add) {
+ $edits[] = &new Text_Diff_Op_change($delete, $add);
+ } elseif ($delete) {
+ $edits[] = &new Text_Diff_Op_delete($delete);
+ } elseif ($add) {
+ $edits[] = &new Text_Diff_Op_add($add);
+ }
+ }
- return $edits;
- }
+ return $edits;
+ }
- /**
- * Divides the Largest Common Subsequence (LCS) of the sequences (XOFF,
- * XLIM) and (YOFF, YLIM) into NCHUNKS approximately equally sized
- * segments.
- *
- * Returns (LCS, PTS). LCS is the length of the LCS. PTS is an array of
- * NCHUNKS+1 (X, Y) indexes giving the diving points between sub
- * sequences. The first sub-sequence is contained in (X0, X1), (Y0, Y1),
- * the second in (X1, X2), (Y1, Y2) and so on. Note that (X0, Y0) ==
- * (XOFF, YOFF) and (X[NCHUNKS], Y[NCHUNKS]) == (XLIM, YLIM).
- *
- * This function assumes that the first lines of the specified portions of
- * the two files do not match, and likewise that the last lines do not
- * match. The caller must trim matching lines from the beginning and end
- * of the portions it is going to specify.
- */
- function _diag ($xoff, $xlim, $yoff, $ylim, $nchunks)
- {
- $flip = false;
+ /**
+ * Divides the Largest Common Subsequence (LCS) of the sequences (XOFF,
+ * XLIM) and (YOFF, YLIM) into NCHUNKS approximately equally sized
+ * segments.
+ *
+ * Returns (LCS, PTS). LCS is the length of the LCS. PTS is an array of
+ * NCHUNKS+1 (X, Y) indexes giving the diving points between sub
+ * sequences. The first sub-sequence is contained in (X0, X1), (Y0, Y1),
+ * the second in (X1, X2), (Y1, Y2) and so on. Note that (X0, Y0) ==
+ * (XOFF, YOFF) and (X[NCHUNKS], Y[NCHUNKS]) == (XLIM, YLIM).
+ *
+ * This function assumes that the first lines of the specified portions of
+ * the two files do not match, and likewise that the last lines do not
+ * match. The caller must trim matching lines from the beginning and end
+ * of the portions it is going to specify.
+ */
+ function _diag ($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 is in X. */
- $flip = true;
- list ($xoff, $xlim, $yoff, $ylim)
- = array($yoff, $ylim, $xoff, $xlim);
- }
+ if ($xlim - $xoff > $ylim - $yoff) {
+ /* Things seems faster (I'm not sure I understand why) when the
+ * shortest sequence is 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]][] = $i;
- }
- }
+ if ($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();
+ $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];
- }
- }
+ $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];
- foreach ($matches as $y) {
- if (empty($this->in_seq[$y])) {
- $k = $this->_lcsPos($y);
- assert($k > 0);
- $ymids[$k] = $ymids[$k - 1];
- break;
- }
- }
+ $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];
+ foreach ($matches as $y) {
+ if (empty($this->in_seq[$y])) {
+ $k = $this->_lcsPos($y);
+ assert($k > 0);
+ $ymids[$k] = $ymids[$k - 1];
+ break;
+ }
+ }
- while (list($junk, $y) = each($matches)) {
- if ($y > $this->seq[$k - 1]) {
- 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 = $this->_lcsPos($y);
- assert($k > 0);
- $ymids[$k] = $ymids[$k - 1];
- }
- }
- }
- }
+ while (list($junk, $y) = each($matches)) {
+ if ($y > $this->seq[$k - 1]) {
+ 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 = $this->_lcsPos($y);
+ 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);
+ $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, $seps);
- }
+ return array($this->lcs, $seps);
+ }
- function _lcsPos($ypos)
- {
- $end = $this->lcs;
- if ($end == 0 || $ypos > $this->seq[$end]) {
- $this->seq[++$this->lcs] = $ypos;
- $this->in_seq[$ypos] = 1;
- return $this->lcs;
- }
+ function _lcsPos($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;
- }
- }
+ $beg = 1;
+ while ($beg < $end) {
+ $mid = (int)(($beg + $end) / 2);
+ if ($ypos > $this->seq[$mid]) {
+ $beg = $mid + 1;
+ } else {
+ $end = $mid;
+ }
+ }
- assert($ypos != $this->seq[$end]);
+ assert($ypos != $this->seq[$end]);
- $this->in_seq[$this->seq[$end]] = false;
- $this->seq[$end] = $ypos;
- $this->in_seq[$ypos] = 1;
- return $end;
- }
+ $this->in_seq[$this->seq[$end]] = false;
+ $this->seq[$end] = $ypos;
+ $this->in_seq[$ypos] = 1;
+ return $end;
+ }
- /**
- * Finds 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;
- }
+ /**
+ * Finds 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;
- }
+ /* 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, $nchunks);
- }
+ if ($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 = $pt2;
- }
- }
- }
+ if ($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 = $pt2;
+ }
+ }
+ }
- /**
- * Adjusts inserts/deletes of identical lines to join changes as much as
- * possible.
- *
- * We do something when a run of changed lines include a line at one end
- * and has an excluded, identical line at the other. We are free to
- * choose which identical line is included. `compareseq' usually chooses
- * the one at the beginning, but usually it is cleaner to consider the
- * following identical line to be the "change".
- *
- * This is extracted verbatim from analyze.c (GNU diffutils-2.7).
- */
- function _shiftBoundaries($lines, &$changed, $other_changed)
- {
- $i = 0;
- $j = 0;
+ /**
+ * Adjusts inserts/deletes of identical lines to join changes as much as
+ * possible.
+ *
+ * We do something when a run of changed lines include a line at one end
+ * and has an excluded, identical line at the other. We are free to
+ * choose which identical line is included. `compareseq' usually chooses
+ * the one at the beginning, but usually it is cleaner to consider the
+ * following identical line to be the "change".
+ *
+ * This is extracted verbatim from analyze.c (GNU diffutils-2.7).
+ */
+ function _shiftBoundaries($lines, &$changed, $other_changed)
+ {
+ $i = 0;
+ $j = 0;
- assert('count($lines) == count($changed)');
- $len = count($lines);
- $other_len = count($other_changed);
+ assert('count($lines) == count($changed)');
+ $len = count($lines);
+ $other_len = count($other_changed);
- while (1) {
- /* Scan forward to find the 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 (1) {
+ /* Scan forward to find the 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]) {
- assert('$j < $other_len && ! $other_changed[$j]');
- $i++; $j++;
- while ($j < $other_len && $other_changed[$j]) {
- $j++;
- }
- }
+ while ($i < $len && ! $changed[$i]) {
+ assert('$j < $other_len && ! $other_changed[$j]');
+ $i++; $j++;
+ while ($j < $other_len && $other_changed[$j]) {
+ $j++;
+ }
+ }
- if ($i == $len) {
- break;
- }
+ if ($i == $len) {
+ break;
+ }
- $start = $i;
+ $start = $i;
- /* Find the end of this run of changes. */
- while (++$i < $len && $changed[$i]) {
- continue;
- }
+ /* 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;
+ 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]) {
- $start--;
- }
- assert('$j > 0');
- while ($other_changed[--$j]) {
- continue;
- }
- assert('$j >= 0 && !$other_changed[$j]');
- }
+ /* Move the changed region back, so long as the previous
+ * unchanged line matches the last changed one. This merges
+ * with previous changed regions. */
+ while ($start > 0 && $lines[$start - 1] == $lines[$i - 1]) {
+ $changed[--$start] = 1;
+ $changed[--$i] = false;
+ while ($start > 0 && $changed[$start - 1]) {
+ $start--;
+ }
+ assert('$j > 0');
+ while ($other_changed[--$j]) {
+ continue;
+ }
+ 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;
+ /* 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]) {
- $i++;
- }
+ /* Move the changed region forward, so long as the first
+ * changed line matches the following unchanged one. This
+ * merges with following changed regions. Do this second, so
+ * that if there are no merges, the changed region is moved
+ * forward as far as possible. */
+ while ($i < $len && $lines[$start] == $lines[$i]) {
+ $changed[$start++] = false;
+ $changed[$i++] = 1;
+ while ($i < $len && $changed[$i]) {
+ $i++;
+ }
- assert('$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 - $start);
+ assert('$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;
- assert('$j > 0');
- while ($other_changed[--$j]) {
- continue;
- }
- assert('$j >= 0 && !$other_changed[$j]');
- }
- }
- }
+ /* 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;
+ assert('$j > 0');
+ while ($other_changed[--$j]) {
+ continue;
+ }
+ assert('$j >= 0 && !$other_changed[$j]');
+ }
+ }
+ }
}