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<?php
declare(strict_types=1);
/*
* This file is part of the TYPO3 CMS project.
*
* It is free software; you can redistribute it and/or modify it under
* the terms of the GNU General Public License, either version 2
* of the License, or any later version.
*
* For the full copyright and license information, please read the
* LICENSE.txt file that was distributed with this source code.
*
* The TYPO3 project - inspiring people to share!
*/
namespace TYPO3\CMS\Core\Utility;
/**
* Class with helper functions for permuting items.
*/
class PermutationUtility
{
/**
* Combines string items of multiple arrays as cross-product into flat items.
*
* Example:
* + meltStringItems([['a', 'b'], ['c', 'd'], ['e', 'f']])
* + results into ['ace', 'acf', 'ade', 'adf', 'bce', 'bcf', 'bde', 'bdf']
*
* @param array[] $payload Distinct array that should be melted
* @param string $previousResult Previous item results
* @return string[]
*/
public static function meltStringItems(array $payload, string $previousResult = ''): array
{
$results = [];
$items = static::nextItems($payload);
foreach ($items as $item) {
if (!(is_string($item) || $item instanceof \Stringable)) {
throw new \LogicException(
sprintf('Expected string, got %s', gettype($item)),
1578164102
);
}
$resultItem = $previousResult . $item;
if (!empty($payload)) {
$results = array_merge(
$results,
static::meltStringItems($payload, $resultItem)
);
continue;
}
$results[] = $resultItem;
}
return $results;
}
/**
* Combines arbitrary items of multiple arrays as cross-product into flat items.
*
* Example:
* + meltArrayItems(['a','b'], ['c','e'], ['f','g'])
* + results into ['a', 'c', 'e'], ['a', 'c', 'f'], ['a', 'd', 'e'], ['a', 'd', 'f'],
* ['b', 'c', 'e'], ['b', 'c', 'f'], ['b', 'd', 'e'], ['b', 'd', 'f'],
*
* @param array[] $payload Distinct items that should be melted
* @param array $previousResult Previous item results
* @return array[]
*/
public static function meltArrayItems(array $payload, array $previousResult = []): array
{
$results = [];
$items = static::nextItems($payload);
foreach ($items as $item) {
$resultItems = $previousResult;
$resultItems[] = $item;
if (!empty($payload)) {
$results = array_merge(
$results,
static::meltArrayItems($payload, $resultItems)
);
continue;
}
$results[] = $resultItems;
}
return $results;
}
protected static function nextItems(array &$payload): iterable
{
$items = array_shift($payload);
if (is_iterable($items)) {
return $items;
}
throw new \LogicException(
sprintf('Expected iterable, got %s', gettype($items)),
1578164101
);
}
}