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MappedIterator.php
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1<?php
28class MappedIterator extends FilterIterator {
30 protected $vCallback;
32 protected $aCallback;
34 protected $cache = [];
35
36 protected $rewound = false; // boolean; whether rewind() has been called
37
54 public function __construct( $iter, $vCallback, array $options = [] ) {
55 if ( is_array( $iter ) ) {
56 $baseIterator = new ArrayIterator( $iter );
57 } elseif ( $iter instanceof Iterator ) {
58 $baseIterator = $iter;
59 } else {
60 throw new UnexpectedValueException( "Invalid base iterator provided." );
61 }
62 parent::__construct( $baseIterator );
63 $this->vCallback = $vCallback;
64 $this->aCallback = $options['accept'] ?? null;
65 }
66
67 public function next(): void {
68 $this->cache = [];
69 parent::next();
70 }
71
72 public function rewind(): void {
73 $this->rewound = true;
74 $this->cache = [];
75 parent::rewind();
76 }
77
78 public function accept(): bool {
79 $inner = $this->getInnerIterator();
80 '@phan-var Iterator $inner';
81 $value = call_user_func( $this->vCallback, $inner->current() );
82 $ok = ( $this->aCallback ) ? call_user_func( $this->aCallback, $value ) : true;
83 if ( $ok ) {
84 $this->cache['current'] = $value;
85 }
86
87 return $ok;
88 }
89
90 #[\ReturnTypeWillChange]
91 public function key() {
92 $this->init();
93
94 return parent::key();
95 }
96
97 public function valid(): bool {
98 $this->init();
99
100 return parent::valid();
101 }
102
103 #[\ReturnTypeWillChange]
104 public function current() {
105 $this->init();
106 if ( parent::valid() ) {
107 return $this->cache['current'];
108 } else {
109 return null; // out of range
110 }
111 }
112
116 protected function init() {
117 if ( !$this->rewound ) {
118 $this->rewind();
119 }
120 }
121}
Convenience class for generating iterators from iterators.
__construct( $iter, $vCallback, array $options=[])
Build a new iterator from a base iterator by having the former wrap the later, returning the result o...
init()
Obviate the usual need for rewind() before using a FilterIterator in a manual loop.
callable null $aCallback