92 lines
2.1 KiB
PHP
92 lines
2.1 KiB
PHP
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<?php
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/*
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* This file is part of the Symfony package.
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*
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* (c) Fabien Potencier <fabien@symfony.com>
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*
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* For the full copyright and license information, please view the LICENSE
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* file that was distributed with this source code.
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*/
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namespace Symfony\Component\Intl\Data\Util;
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use Symfony\Component\Intl\Exception\OutOfBoundsException;
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/**
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* Implements a ring buffer.
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*
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* A ring buffer is an array-like structure with a fixed size. If the buffer
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* is full, the next written element overwrites the first bucket in the buffer,
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* then the second and so on.
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*
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* @author Bernhard Schussek <bschussek@gmail.com>
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*
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* @template TKey of array-key
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* @template TValue
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*
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* @implements \ArrayAccess<TKey, TValue>
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*
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* @internal
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*/
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class RingBuffer implements \ArrayAccess
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{
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/** @var array<int, TValue> */
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private array $values = [];
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/** @var array<TKey, int> */
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private array $indices = [];
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private int $cursor = 0;
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private int $size;
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public function __construct(int $size)
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{
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$this->size = $size;
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}
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/**
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* {@inheritdoc}
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*/
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public function offsetExists(mixed $key): bool
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{
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return isset($this->indices[$key]);
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}
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/**
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* {@inheritdoc}
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*/
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public function offsetGet(mixed $key): mixed
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{
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if (!isset($this->indices[$key])) {
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throw new OutOfBoundsException(sprintf('The index "%s" does not exist.', $key));
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}
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return $this->values[$this->indices[$key]];
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}
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/**
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* {@inheritdoc}
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*/
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public function offsetSet(mixed $key, mixed $value): void
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{
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if (false !== ($keyToRemove = array_search($this->cursor, $this->indices))) {
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unset($this->indices[$keyToRemove]);
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}
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$this->values[$this->cursor] = $value;
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$this->indices[$key] = $this->cursor;
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$this->cursor = ($this->cursor + 1) % $this->size;
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}
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/**
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* {@inheritdoc}
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*/
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public function offsetUnset(mixed $key): void
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{
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if (isset($this->indices[$key])) {
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$this->values[$this->indices[$key]] = null;
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unset($this->indices[$key]);
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}
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}
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}
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