includes/MappedIterator.php

   1 <?php
   2 /**
   3  * Convenience class for generating iterators from iterators.
   4  *
   5  * This program is free software; you can redistribute it and/or modify
   6  * it under the terms of the GNU General Public License as published by
   7  * the Free Software Foundation; either version 2 of the License, or
   8  * (at your option) any later version.
   9  *
  10  * This program is distributed in the hope that it will be useful,
  11  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
  13  * GNU General Public License for more details.
  14  *
  15  * You should have received a copy of the GNU General Public License along
  16  * with this program; if not, write to the Free Software Foundation, Inc.,
  17  * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
  18  * http://www.gnu.org/copyleft/gpl.html
  19  *
  20  * @file
  21  * @author Aaron Schulz
  22  */
  23
  24 /**
  25  * Convenience class for generating iterators from iterators.
  26  *
  27  * @since 1.21
  28  */
  29 class MappedIterator implements Iterator {
  30         /** @var Iterator */
  31         protected $baseIterator;
  32         /** @var callable */
  33         protected $vCallback;
  34
  35         /**
  36          * Build an new iterator from a base iterator by having the former wrap the
  37          * later, returning the result of "value" callback for each current() invocation.
  38          * The callback takes the result of current() on the base iterator as an argument.
  39          * The keys of the base iterator are reused verbatim.
  40          *
  41          * @param Iterator|Array $iter
  42          * @param callable $vCallback
  43          * @throws MWException
  44          */
  45         public function __construct( $iter, $vCallback ) {
  46                 if ( is_array( $iter ) ) {
  47                         $this->baseIterator = new ArrayIterator( $iter );
  48                 } elseif ( $iter instanceof Iterator ) {
  49                         $this->baseIterator = $iter;
  50                 } else {
  51                         throw new MWException( "Invalid base iterator provided." );
  52                 }
  53                 $this->vCallback = $vCallback;
  54         }
  55
  56         /**
  57          * @return void
  58          */
  59         public function rewind() {
  60                 $this->baseIterator->rewind();
  61         }
  62
  63         /**
  64          * @return Mixed|null Returns null if out of range
  65          */
  66         public function current() {
  67                 if ( !$this->baseIterator->valid() ) {
  68                         return null; // out of range
  69                 }
  70                 return call_user_func_array( $this->vCallback, array( $this->baseIterator->current() ) );
  71         }
  72
  73         /**
  74          * @return Mixed|null Returns null if out of range
  75          */
  76         public function key() {
  77                 if ( !$this->baseIterator->valid() ) {
  78                         return null; // out of range
  79                 }
  80                 return $this->baseIterator->key();
  81         }
  82
  83         /**
  84          * @return void
  85          */
  86         public function next() {
  87                 $this->baseIterator->next();
  88         }
  89
  90         /**
  91          * @return bool
  92          */
  93         public function valid() {
  94                 return $this->baseIterator->valid();
  95         }
  96 }