Gecko [ v3.cesa.co.za ]

Name	Size	Permission	Date
Exception	[ DIR ]	drwxrwxr-x	2026-08-17 03:12
Output	[ DIR ]	drwxrwxr-x	2026-08-17 03:12
.htaccess	237 B	-r-xr-xr-x	2026-08-17 03:12
Chunk.php	1.61 KB	-rwxrwxr-x	2024-03-02 06:30
Diff.php	1.1 KB	-rwxrwxr-x	2024-03-02 06:30
Differ.php	9.22 KB	-rwxrwxr-x	2024-03-02 06:30
Line.php	848 B	-rwxrwxr-x	2024-03-02 06:30
LongestCommonSubsequenceCalculator.php	486 B	-rwxrwxr-x	2024-03-02 06:30
MemoryEfficientLongestCommonSubsequenceCalculator.php	2.45 KB	-rwxrwxr-x	2024-03-02 06:30
Parser.php	3.02 KB	-rwxrwxr-x	2024-03-02 06:30
TimeEfficientLongestCommonSubsequenceCalculator.php	2.31 KB	-rwxrwxr-x	2024-03-02 06:30

Rename

<?php declare(strict_types=1);
/*
 * This file is part of sebastian/diff.
 *
 * (c) Sebastian Bergmann <sebastian@phpunit.de>
 *
 * For the full copyright and license information, please view the LICENSE
 * file that was distributed with this source code.
 */
namespace SebastianBergmann\Diff;

use function array_fill;
use function array_merge;
use function array_reverse;
use function array_slice;
use function count;
use function in_array;
use function max;

final class MemoryEfficientLongestCommonSubsequenceCalculator implements LongestCommonSubsequenceCalculator
{
    /**
     * {@inheritdoc}
     */
    public function calculate(array $from, array $to): array
    {
        $cFrom = count($from);
        $cTo   = count($to);

if ($cFrom === 0) {
            return [];
        }

if ($cFrom === 1) {
            if (in_array($from[0], $to, true)) {
                return [$from[0]];
            }

return [];
        }

$i         = (int) ($cFrom / 2);
        $fromStart = array_slice($from, 0, $i);
        $fromEnd   = array_slice($from, $i);
        $llB       = $this->length($fromStart, $to);
        $llE       = $this->length(array_reverse($fromEnd), array_reverse($to));
        $jMax      = 0;
        $max       = 0;

for ($j = 0; $j <= $cTo; $j++) {
            $m = $llB[$j] + $llE[$cTo - $j];

if ($m >= $max) {
                $max  = $m;
                $jMax = $j;
            }
        }

$toStart = array_slice($to, 0, $jMax);
        $toEnd   = array_slice($to, $jMax);

return array_merge(
            $this->calculate($fromStart, $toStart),
            $this->calculate($fromEnd, $toEnd)
        );
    }

private function length(array $from, array $to): array
    {
        $current = array_fill(0, count($to) + 1, 0);
        $cFrom   = count($from);
        $cTo     = count($to);

for ($i = 0; $i < $cFrom; $i++) {
            $prev = $current;

for ($j = 0; $j < $cTo; $j++) {
                if ($from[$i] === $to[$j]) {
                    $current[$j + 1] = $prev[$j] + 1;
                } else {
                    // don't use max() to avoid function call overhead
                    if ($current[$j] > $prev[$j + 1]) {
                        $current[$j + 1] = $current[$j];
                    } else {
                        $current[$j + 1] = $prev[$j + 1];
                    }
                }
            }
        }

return $current;
    }
}