Text_Diff_Engine_native::diff( $from_lines, $to_lines )

41    function diff($from_lines, $to_lines)42    {43        array_walk($from_lines, array('Text_Diff', 'trimNewlines'));44        array_walk($to_lines, array('Text_Diff', 'trimNewlines'));45 46        $n_from = count($from_lines);47        $n_to = count($to_lines);48 49        $this->xchanged = $this->ychanged = array();50        $this->xv = $this->yv = array();51        $this->xind = $this->yind = array();52        unset($this->seq);53        unset($this->in_seq);54        unset($this->lcs);55 56        // Skip leading common lines.57        for ($skip = 0; $skip < $n_from && $skip < $n_to; $skip++) {58            if ($from_lines[$skip] !== $to_lines[$skip]) {59                break;60            }61            $this->xchanged[$skip] = $this->ychanged[$skip] = false;62        }63 64        // Skip trailing common lines.65        $xi = $n_from; $yi = $n_to;66        for ($endskip = 0; --$xi > $skip && --$yi > $skip; $endskip++) {67            if ($from_lines[$xi] !== $to_lines[$yi]) {68                break;69            }70            $this->xchanged[$xi] = $this->ychanged[$yi] = false;71        }72 73        // Ignore lines which do not exist in both files.74        for ($xi = $skip; $xi < $n_from - $endskip; $xi++) {75            $xhash[$from_lines[$xi]] = 1;76        }77        for ($yi = $skip; $yi < $n_to - $endskip; $yi++) {78            $line = $to_lines[$yi];79            if (($this->ychanged[$yi] = empty($xhash[$line]))) {80                continue;81            }82            $yhash[$line] = 1;83            $this->yv[] = $line;84            $this->yind[] = $yi;85        }86        for ($xi = $skip; $xi < $n_from - $endskip; $xi++) {87            $line = $from_lines[$xi];88            if (($this->xchanged[$xi] = empty($yhash[$line]))) {89                continue;90            }91            $this->xv[] = $line;92            $this->xind[] = $xi;93        }94 95        // Find the LCS.96        $this->_compareseq(0, count($this->xv), 0, count($this->yv));97 98        // Merge edits when possible.99        $this->_shiftBoundaries($from_lines, $this->xchanged, $this->ychanged);100        $this->_shiftBoundaries($to_lines, $this->ychanged, $this->xchanged);101 102        // Compute the edit operations.103        $edits = array();104        $xi = $yi = 0;105        while ($xi < $n_from || $yi < $n_to) {106            assert($yi < $n_to || $this->xchanged[$xi]);107            assert($xi < $n_from || $this->ychanged[$yi]);108 109            // Skip matching "snake".110            $copy = array();111            while ($xi < $n_from && $yi < $n_to112                   && !$this->xchanged[$xi] && !$this->ychanged[$yi]) {113                $copy[] = $from_lines[$xi++];114                ++$yi;115            }116            if ($copy) {117                $edits[] = new Text_Diff_Op_copy($copy);118            }119 120            // Find deletes & adds.
PHP	Compiled	Executed	Branches	Notes
8.6-dev	238	90–103	30
8.5	238	90–103	30
8.4	238	90–103	30
8.3	238	90–103	30
8.2	238	90–103	30
8.1	238	90–103	30	2 fewer instructions than PHP 7.4
7.4	240	92–105	30