|
1
|
|
|
<?php namespace Mbh\Iterator; |
|
2
|
|
|
|
|
3
|
|
|
/** |
|
4
|
|
|
* MBHFramework |
|
5
|
|
|
* |
|
6
|
|
|
* @link https://github.com/MBHFramework/mbh-framework |
|
7
|
|
|
* @copyright Copyright (c) 2017 Ulises Jeremias Cornejo Fandos |
|
8
|
|
|
* @license https://github.com/MBHFramework/mbh-framework/blob/master/LICENSE (MIT License) |
|
9
|
|
|
*/ |
|
10
|
|
|
|
|
11
|
|
|
use ArrayAccess; |
|
12
|
|
|
use LimitIterator; |
|
13
|
|
|
use JsonSerializable; |
|
14
|
|
|
use Countable; |
|
15
|
|
|
use Iterator; |
|
16
|
|
|
use InvalidArgumentException; |
|
17
|
|
|
use RuntimeException; |
|
18
|
|
|
|
|
19
|
|
|
/** |
|
20
|
|
|
* Iterator to allow a slice to be used like an array |
|
21
|
|
|
*/ |
|
22
|
|
|
|
|
23
|
|
|
class SliceIterator extends LimitIterator implements ArrayAccess, Countable, JsonSerializable |
|
24
|
|
|
{ |
|
25
|
|
|
protected $count = 0; |
|
26
|
|
|
protected $begin = 0; |
|
27
|
|
|
|
|
28
|
|
|
const INVALID_INDEX = 'Index invalid or out of range'; |
|
29
|
|
|
|
|
30
|
|
|
/** |
|
31
|
|
|
* Build an iterator over a slice of an ArrayAccess object |
|
32
|
|
|
* Unlike a LimitIterator, the $end defines the last index, not the count |
|
33
|
|
|
* |
|
34
|
|
|
* @param Iterator $iterator An ArrayAccess iterator, e.g. SplFixedArray |
|
35
|
|
|
* @param int $begin The starting offset of the slice |
|
36
|
|
|
* @param int $end The last index of the slice |
|
37
|
|
|
*/ |
|
38
|
|
|
public function __construct(Iterator $iterator, $begin = 0, $end = null) |
|
39
|
|
|
{ |
|
40
|
|
|
if (!( |
|
41
|
|
|
$iterator instanceof ArrayAccess |
|
42
|
|
|
&& $iterator instanceof Countable |
|
43
|
|
|
)) { |
|
44
|
|
|
throw new InvalidArgumentException('Iterator must be a Countable ArrayAccess'); |
|
45
|
|
|
} |
|
46
|
|
|
|
|
47
|
|
|
$count = count($iterator); |
|
48
|
|
|
|
|
49
|
|
|
// Negative begin means start from the end |
|
50
|
|
|
if ($begin < 0) { |
|
51
|
|
|
$begin = max(0, $count + $begin); |
|
52
|
|
|
} |
|
53
|
|
|
|
|
54
|
|
|
// If no end set, assume whole array |
|
55
|
|
|
if ($end === null) { |
|
56
|
|
|
$end = $count; |
|
57
|
|
|
} elseif ($end < 0) { |
|
58
|
|
|
// Ends counting back from start |
|
59
|
|
|
$end = max($begin, $count + $end); |
|
60
|
|
|
} |
|
61
|
|
|
|
|
62
|
|
|
// Set the size of iterable object, for quick-lookup |
|
63
|
|
|
$this->count = max(0, $end - $begin); |
|
64
|
|
|
|
|
65
|
|
|
// Need to store the starting offset to adjust by |
|
66
|
|
|
$this->begin = $begin; |
|
67
|
|
|
|
|
68
|
|
|
// Init as LimitIterator |
|
69
|
|
|
parent::__construct($iterator, $this->begin, $this->count); |
|
70
|
|
|
} |
|
71
|
|
|
|
|
72
|
|
|
/** |
|
73
|
|
|
* Rewind, extended for clean results on empty sets |
|
74
|
|
|
*/ |
|
75
|
|
|
public function rewind() |
|
76
|
|
|
{ |
|
77
|
|
|
// no need to rewind on empty sets |
|
78
|
|
|
if ($this->count > 0) { |
|
79
|
|
|
parent::rewind(); |
|
80
|
|
|
} |
|
81
|
|
|
} |
|
82
|
|
|
|
|
83
|
|
|
/** |
|
84
|
|
|
* Countable |
|
85
|
|
|
*/ |
|
86
|
|
|
public function count(): int |
|
87
|
|
|
{ |
|
88
|
|
|
return $this->count; |
|
89
|
|
|
} |
|
90
|
|
|
|
|
91
|
|
|
/** |
|
92
|
|
|
* ArrayAccess |
|
93
|
|
|
*/ |
|
94
|
|
|
public function offsetExists($offset) |
|
95
|
|
|
{ |
|
96
|
|
|
return $offset >= 0 && $offset < $this->count; |
|
97
|
|
|
} |
|
98
|
|
|
|
|
99
|
|
|
public function offsetGet($offset) |
|
100
|
|
|
{ |
|
101
|
|
|
if ($this->offsetExists($offset)) { |
|
102
|
|
|
return iterator_to_array($this)->offsetGet($offset + $this->begin); |
|
103
|
|
|
} else { |
|
104
|
|
|
throw new RuntimeException(self::INVALID_INDEX); |
|
105
|
|
|
} |
|
106
|
|
|
} |
|
107
|
|
|
|
|
108
|
|
|
public function offsetSet($offset, $value) |
|
109
|
|
|
{ |
|
110
|
|
|
return iterator_to_array($this)->offsetSet($offset + $this->begin, $value); |
|
111
|
|
|
} |
|
112
|
|
|
|
|
113
|
|
|
public function offsetUnset($offset) |
|
114
|
|
|
{ |
|
115
|
|
|
return iterator_to_array($this)->offsetUnset($offset + $this->begin); |
|
116
|
|
|
} |
|
117
|
|
|
|
|
118
|
|
|
/** |
|
119
|
|
|
* JsonSerializable |
|
120
|
|
|
*/ |
|
121
|
|
|
public function jsonSerialize() |
|
122
|
|
|
{ |
|
123
|
|
|
return $this->toArray(); |
|
124
|
|
|
} |
|
125
|
|
|
|
|
126
|
|
|
public function toArray() |
|
127
|
|
|
{ |
|
128
|
|
|
return iterator_to_array($this, false); |
|
129
|
|
|
} |
|
130
|
|
|
} |
|
131
|
|
|
|
MBHFramework /
structures
