public function testCleanupSemantic()
{
// Cleanup semantically trivial equalities.
// Null case.
$this->d->setChanges(array());
$this->d->cleanupSemantic();
$this->assertEquals(array(), $this->d->getChanges());
// No elimination #1.
$this->d->setChanges(array(array(Diff::DELETE, "ab"), array(Diff::INSERT, "cd"), array(Diff::EQUAL, "12"), array(Diff::DELETE, "e")));
$this->d->cleanupSemantic();
$this->assertEquals(array(array(Diff::DELETE, "ab"), array(Diff::INSERT, "cd"), array(Diff::EQUAL, "12"), array(Diff::DELETE, "e")), $this->d->getChanges());
// No elimination #2.
$this->d->setChanges(array(array(Diff::DELETE, "abc"), array(Diff::INSERT, "ABC"), array(Diff::EQUAL, "1234"), array(Diff::DELETE, "wxyz")));
$this->d->cleanupSemantic();
$this->assertEquals(array(array(Diff::DELETE, "abc"), array(Diff::INSERT, "ABC"), array(Diff::EQUAL, "1234"), array(Diff::DELETE, "wxyz")), $this->d->getChanges());
// Simple elimination.
$this->d->setChanges(array(array(Diff::DELETE, "a"), array(Diff::EQUAL, "b"), array(Diff::DELETE, "c")));
$this->d->cleanupSemantic();
$this->assertEquals(array(array(Diff::DELETE, "abc"), array(Diff::INSERT, "b")), $this->d->getChanges());
// Backpass elimination.
$this->d->setChanges(array(array(Diff::DELETE, "ab"), array(Diff::EQUAL, "cd"), array(Diff::DELETE, "e"), array(Diff::EQUAL, "f"), array(Diff::INSERT, "g")));
$this->d->cleanupSemantic();
$this->assertEquals(array(array(Diff::DELETE, "abcdef"), array(Diff::INSERT, "cdfg")), $this->d->getChanges());
// Multiple eliminations.
$this->d->setChanges(array(array(Diff::INSERT, "1"), array(Diff::EQUAL, "A"), array(Diff::DELETE, "B"), array(Diff::INSERT, "2"), array(Diff::EQUAL, "_"), array(Diff::INSERT, "1"), array(Diff::EQUAL, "A"), array(Diff::DELETE, "B"), array(Diff::INSERT, "2")));
$this->d->cleanupSemantic();
$this->assertEquals(array(array(Diff::DELETE, "AB_AB"), array(Diff::INSERT, "1A2_1A2")), $this->d->getChanges());
// Word boundaries.
$this->d->setChanges(array(array(Diff::EQUAL, "The c"), array(Diff::DELETE, "ow and the c"), array(Diff::EQUAL, "at.")));
$this->d->cleanupSemantic();
$this->assertEquals(array(array(Diff::EQUAL, "The "), array(Diff::DELETE, "cow and the "), array(Diff::EQUAL, "cat.")), $this->d->getChanges());
// No overlap elimination.
$this->d->setChanges(array(array(Diff::DELETE, "abcxx"), array(Diff::INSERT, "xxdef")));
$this->d->cleanupSemantic();
$this->assertEquals(array(array(Diff::DELETE, "abcxx"), array(Diff::INSERT, "xxdef")), $this->d->getChanges());
// Overlap elimination.
$this->d->setChanges(array(array(Diff::DELETE, "abcxxx"), array(Diff::INSERT, "xxxdef")));
$this->d->cleanupSemantic();
$this->assertEquals(array(array(Diff::DELETE, "abc"), array(Diff::EQUAL, "xxx"), array(Diff::INSERT, "def")), $this->d->getChanges());
// Reverse overlap elimination.
$this->d->setChanges(array(array(Diff::DELETE, "xxxabc"), array(Diff::INSERT, "defxxx")));
$this->d->cleanupSemantic();
$this->assertEquals(array(array(Diff::INSERT, "def"), array(Diff::EQUAL, "xxx"), array(Diff::DELETE, "abc")), $this->d->getChanges());
// Two overlap eliminations.
$this->d->setChanges(array(array(Diff::DELETE, "abcd1212"), array(Diff::INSERT, "1212efghi"), array(Diff::EQUAL, "----"), array(Diff::DELETE, "A3"), array(Diff::INSERT, "3BC")));
$this->d->cleanupSemantic();
$this->assertEquals(array(array(Diff::DELETE, "abcd"), array(Diff::EQUAL, "1212"), array(Diff::INSERT, "efghi"), array(Diff::EQUAL, "----"), array(Diff::DELETE, "A"), array(Diff::EQUAL, "3"), array(Diff::INSERT, "BC")), $this->d->getChanges());
}
/**
* Do a quick line-level diff on both strings, then rediff the parts for greater accuracy.
* This speedup can produce non-minimal diffs.
*
* @param string $text1 Old string to be diffed.
* @param string $text2 New string to be diffed.
* @param int $deadline Time when the diff should be complete by.
*
* @return array Array of changes.
*/
protected function lineMode($text1, $text2, $deadline)
{
// Scan the text on a line-by-line basis first.
list($text1, $text2, $lineArray) = $this->getToolkit()->linesToChars($text1, $text2);
$diff = new Diff();
$diff->main($text1, $text2, false, $deadline);
$diffs = $diff->getChanges();
// Convert the diff back to original text.
$this->getToolkit()->charsToLines($diffs, $lineArray);
$diff->setChanges($diffs);
// Eliminate freak matches (e.g. blank lines)
$diff->cleanupSemantic();
$diffs = $diff->getChanges();
// Rediff any replacement blocks, this time character-by-character.
// Add a dummy entry at the end.
array_push($diffs, array(self::EQUAL, ''));
$pointer = 0;
$countDelete = 0;
$countInsert = 0;
$textDelete = '';
$textInsert = '';
while ($pointer < count($diffs)) {
switch ($diffs[$pointer][0]) {
case self::DELETE:
$countDelete++;
$textDelete .= $diffs[$pointer][1];
break;
case self::INSERT:
$countInsert++;
$textInsert .= $diffs[$pointer][1];
break;
case self::EQUAL:
// Upon reaching an equality, check for prior redundancies.
if ($countDelete > 0 && $countInsert > 0) {
// Delete the offending records and add the merged ones.
$subDiff = new Diff();
$subDiff->main($textDelete, $textInsert, false, $deadline);
array_splice($diffs, $pointer - $countDelete - $countInsert, $countDelete + $countInsert, $subDiff->getChanges());
$pointer = $pointer - $countDelete - $countInsert + count($subDiff->getChanges());
}
$countDelete = 0;
$countInsert = 0;
$textDelete = '';
$textInsert = '';
break;
}
$pointer++;
}
// Remove the dummy entry at the end.
array_pop($diffs);
return $diffs;
}
/**
* Reduce the number of edits by eliminating semantically trivial equalities.
* Modifies $diffs.
*
* @param array $diffs Array of diff arrays.
*/
public function diff_cleanupSemantic(&$diffs)
{
$this->diff->setChanges($diffs);
$this->diff->cleanupSemantic();
$diffs = $this->diff->getChanges();
}
