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1 | <?php |
2 | ||
3 | /* | |
4 | * This file is part of the Symfony package. | |
5 | * | |
6 | * (c) Fabien Potencier <fabien@symfony.com> | |
7 | * | |
8 | * For the full copyright and license information, please view the LICENSE | |
9 | * file that was distributed with this source code. | |
10 | */ | |
11 | ||
12 | namespace Symfony\Component\Intl\ResourceBundle\Util; | |
13 | ||
14 | use Symfony\Component\Intl\Exception\OutOfBoundsException; | |
15 | ||
16 | /** | |
17 | * Implements a ring buffer. | |
18 | * | |
19 | * A ring buffer is an array-like structure with a fixed size. If the buffer | |
20 | * is full, the next written element overwrites the first bucket in the buffer, | |
21 | * then the second and so on. | |
22 | * | |
23 | * @author Bernhard Schussek <bschussek@gmail.com> | |
24 | */ | |
25 | class RingBuffer implements \ArrayAccess | |
26 | { | |
27 | private $values = array(); | |
28 | ||
29 | private $indices = array(); | |
30 | ||
31 | private $cursor = 0; | |
32 | ||
33 | private $size; | |
34 | ||
35 | public function __construct($size) | |
36 | { | |
37 | $this->size = $size; | |
38 | } | |
39 | ||
40 | /** | |
41 | * {@inheritdoc} | |
42 | */ | |
43 | public function offsetExists($key) | |
44 | { | |
45 | return isset($this->indices[$key]); | |
46 | } | |
47 | ||
48 | /** | |
49 | * {@inheritdoc} | |
50 | */ | |
51 | public function offsetGet($key) | |
52 | { | |
53 | if (!isset($this->indices[$key])) { | |
54 | throw new OutOfBoundsException(sprintf( | |
55 | 'The index "%s" does not exist.', | |
56 | $key | |
57 | )); | |
58 | } | |
59 | ||
60 | return $this->values[$this->indices[$key]]; | |
61 | } | |
62 | ||
63 | /** | |
64 | * {@inheritdoc} | |
65 | */ | |
66 | public function offsetSet($key, $value) | |
67 | { | |
68 | if (false !== ($keyToRemove = array_search($this->cursor, $this->indices))) { | |
69 | unset($this->indices[$keyToRemove]); | |
70 | } | |
71 | ||
72 | $this->values[$this->cursor] = $value; | |
73 | $this->indices[$key] = $this->cursor; | |
74 | ||
75 | $this->cursor = ($this->cursor + 1) % $this->size; | |
76 | } | |
77 | ||
78 | /** | |
79 | * {@inheritdoc} | |
80 | */ | |
81 | public function offsetUnset($key) | |
82 | { | |
83 | if (isset($this->indices[$key])) { | |
84 | $this->values[$this->indices[$key]] = null; | |
85 | unset($this->indices[$key]); | |
86 | } | |
87 | } | |
88 | } |