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<?php |
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/** |
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* For the full copyright and license information, please view |
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* the LICENSE file that was distributed with this source code. |
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*/ |
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declare(strict_types=1); |
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namespace loophp\iterators; |
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use ArrayIterator; |
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use Generator; |
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use Iterator; |
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use IteratorAggregate; |
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use Traversable; |
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use const PHP_INT_MAX; |
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use const PHP_INT_MIN; |
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/** |
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* @template TKey |
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* @template T |
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* |
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* @implements IteratorAggregate<TKey, T> |
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*/ |
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final class RandomIterableAggregate implements IteratorAggregate |
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{ |
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/** |
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* @var IteratorAggregate<int, array{0: TKey, 1: T}> |
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*/ |
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private IteratorAggregate $iteratorAggregate; |
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private int $seed; |
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/** |
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* @param iterable<TKey, T> $iterable |
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*/ |
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public function __construct(iterable $iterable, int $seed = 0) |
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{ |
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$this->iteratorAggregate = new PackIterableAggregate($iterable); |
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$this->seed = $seed; |
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} |
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/** |
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* @return Traversable<TKey, T> |
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*/ |
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public function getIterator(): Traversable |
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{ |
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mt_srand($this->seed); |
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yield from $this->randomize($this->iteratorAggregate, $this->seed); |
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} |
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/** |
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* @param Traversable<int, array{0: TKey, 1: T}> $traversable |
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* |
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* @return Generator<TKey, T> |
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*/ |
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private function randomize(Traversable $traversable, int $seed): Generator |
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{ |
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$isQueueEmpty = true; |
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/** @var ArrayIterator<int, array{0: TKey, 1: T}> $queue */ |
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$queue = new ArrayIterator(); |
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foreach (new UnpackIterableAggregate($traversable) as $key => $value) { |
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if (mt_rand(0, $seed) === 0) { |
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yield $key => $value; |
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continue; |
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} |
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$queue->append([$key, $value]); |
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$isQueueEmpty = false; |
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} |
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if (false === $isQueueEmpty) { |
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yield from $this->randomize($queue, $seed); |
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} |
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} |
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} |
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