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63f00a3f FB |
1 | <?php |
2 | /*************************************************************************** | |
a7f778a5 | 3 | * Copyright (C) 2003-2009 Polytechnique.org * |
63f00a3f FB |
4 | * http://opensource.polytechnique.org/ * |
5 | * * | |
6 | * This program is free software; you can redistribute it and/or modify * | |
7 | * it under the terms of the GNU General Public License as published by * | |
8 | * the Free Software Foundation; either version 2 of the License, or * | |
9 | * (at your option) any later version. * | |
10 | * * | |
11 | * This program is distributed in the hope that it will be useful, * | |
12 | * but WITHOUT ANY WARRANTY; without even the implied warranty of * | |
13 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * | |
14 | * GNU General Public License for more details. * | |
15 | * * | |
16 | * You should have received a copy of the GNU General Public License * | |
17 | * along with this program; if not, write to the Free Software * | |
18 | * Foundation, Inc., * | |
19 | * 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA * | |
20 | ***************************************************************************/ | |
21 | ||
5177a1b5 FB |
22 | class PlIteratorUtils |
23 | { | |
24 | /** Build an iterator over an array. | |
25 | * @param array The array. | |
26 | * @param depth The depth of iteration. | |
27 | * @return an iterator that return entries in the form | |
28 | * array(key => array(0 => key_for_depth0 [, 1 => key_for_depths1, ...]), | |
29 | * value => the value); | |
30 | */ | |
31 | public static function fromArray(array $array, $depth = 1) | |
32 | { | |
33 | return new PlArrayIterator($array, $depth); | |
34 | } | |
35 | ||
36 | ||
37 | /** Sort an iterator using the given sort callback. | |
38 | * @param iterator The iterator to sort. | |
39 | * @param callback The callback for comparison. | |
40 | * @return a new iterator with the entries sorted. | |
41 | */ | |
42 | public static function sort(PlIterator $iterator, $callback) | |
43 | { | |
44 | $heap = new PlHeap($callback); | |
45 | while ($item = $iterator->next()) { | |
46 | $heap->push($item); | |
47 | } | |
48 | return $heap->iterator(); | |
49 | } | |
50 | ||
51 | ||
52 | /** Merge several iterator into a unique one. | |
53 | * @param iterators Array of iterators. | |
54 | * @param callback The callback for comparison. | |
55 | * @param sorted Tell wether the iterators are already sorted using the given callback. | |
56 | * @return an iterator. | |
57 | */ | |
58 | public static function merge(array $iterators, $callback, $sorted = true) | |
59 | { | |
60 | return new PlMergeIterator($iterators, $callback, $sorted); | |
61 | } | |
62 | } | |
63 | ||
64 | ||
65 | /** Iterates over an array. | |
66 | */ | |
63f00a3f FB |
67 | class PlArrayIterator implements PlIterator |
68 | { | |
69 | private $array; | |
70 | private $depth; | |
71 | ||
72 | private $_its = array(); | |
73 | ||
74 | private $_total; | |
75 | private $_first; | |
76 | private $_last; | |
77 | private $_pos; | |
78 | ||
79 | public function __construct(array &$array, $depth = 1) | |
80 | { | |
81 | $this->array =& $array; | |
82 | $this->depth = $depth; | |
83 | $this->_total = $this->count($array, $depth - 1); | |
84 | $this->_pos = 0; | |
85 | $this->_first = false; | |
86 | $this->_last = false; | |
87 | ||
88 | for ($i = 0 ; $i < $depth ; ++$i) { | |
89 | if ($i == 0) { | |
90 | $this->_its[] = $array; | |
91 | } else { | |
92 | $this->_its[] = current($this->_its[$i - 1]); | |
93 | } | |
94 | reset($this->_its[$i]); | |
95 | } | |
96 | } | |
97 | ||
98 | private function count(array &$array, $depth) | |
99 | { | |
100 | if ($depth == 0) { | |
101 | return count($array); | |
102 | } else { | |
103 | $sum = 0; | |
104 | foreach ($array as &$item) { | |
105 | $sum += $this->count($item, $depth - 1); | |
106 | } | |
107 | return $sum; | |
108 | } | |
109 | } | |
110 | ||
111 | private function nextArray($depth) | |
112 | { | |
113 | if ($depth == 0) { | |
114 | return; | |
115 | } | |
116 | $this->_its[$depth] = next($this->_its[$depth - 1]); | |
117 | if ($this->_its[$depth] === false) { | |
118 | $this->nextArray($depth - 1); | |
119 | if ($this->_its[$depth - 1] === false) { | |
120 | return; | |
121 | } | |
122 | $this->_its[$depth] = current($this->_its[$depth - 1]); | |
123 | } | |
124 | reset($this->_its[$depth]); | |
125 | } | |
126 | ||
127 | public function next() | |
128 | { | |
129 | ++$this->_pos; | |
130 | $this->_first = ($this->_total > 0 && $this->_pos == 1); | |
131 | $this->_last = ($this->_pos == $this->_total); | |
132 | if ($this->_pos > $this->_total) { | |
133 | return null; | |
134 | } | |
135 | ||
136 | $val = current($this->_its[$this->depth - 1]); | |
137 | if ($val === false) { | |
138 | $this->nextArray($this->depth - 1); | |
139 | $val = current($this->_its[$this->depth - 1]); | |
140 | if ($val === false) { | |
141 | return null; | |
142 | } | |
143 | } | |
144 | $keys = array(); | |
145 | for ($i = 0 ; $i < $this->depth ; ++$i) { | |
146 | $keys[] = key($this->_its[$i]); | |
147 | } | |
148 | next($this->_its[$this->depth - 1]); | |
149 | return array('keys' => $keys, | |
150 | 'value' => $val); | |
151 | } | |
152 | ||
153 | public function total() | |
154 | { | |
155 | return $this->_total; | |
156 | } | |
157 | ||
158 | public function first() | |
159 | { | |
160 | return $this->_first; | |
161 | } | |
162 | ||
163 | public function last() | |
164 | { | |
165 | return $this->_last; | |
166 | } | |
167 | } | |
168 | ||
5177a1b5 FB |
169 | |
170 | /** Iterator that return the result of a merge of several iterators. | |
171 | */ | |
172 | class PlMergeIterator implements PlIterator | |
173 | { | |
174 | /* The heap is field with entries with the form: | |
175 | * array('it' => id of the iterator this entry come from, | |
176 | * 'value' => value of the entry). | |
177 | */ | |
178 | private $heap; | |
179 | private $preComputed = false; | |
180 | private $comparator; | |
181 | private $iterators; | |
182 | private $_total; | |
183 | private $pos; | |
184 | ||
185 | public function __construct(array $iterators, $callback, $sorted = true) | |
186 | { | |
187 | $this->heap = new PlHeap(array($this, 'compare')); | |
188 | $this->_total = 0; | |
189 | $this->comparator = $callback; | |
190 | if ($sorted) { | |
191 | $this->iterators = $iterators; | |
192 | foreach ($this->iterators as $key => &$it) { | |
193 | $this->_total += $it->total(); | |
194 | $item = $it->next(); | |
195 | if (!is_null($item)) { | |
196 | $this->heap->push(array('it' => $key, 'value' => $item)); | |
197 | } | |
198 | } | |
199 | } else { | |
200 | $this->preComputed = true; | |
201 | foreach ($iterators as $key => &$it) { | |
202 | $this->_total += $it->total(); | |
203 | while (!is_null($item = $it->next())) { | |
204 | $this->heap->push(array('it' => $key, 'value' => $item)); | |
205 | } | |
206 | } | |
207 | } | |
208 | $this->pos = 0; | |
209 | } | |
210 | ||
211 | /** Compare two entries of the heap using the comparator of the user. | |
212 | */ | |
213 | public function compare($a, $b) | |
214 | { | |
215 | $cp = call_user_func($this->comparator, $a['value'], $b['value']); | |
216 | if ($cp == 0) { | |
217 | return $a['it'] - $b['it']; | |
218 | } | |
219 | return $cp; | |
220 | } | |
221 | ||
222 | public function total() | |
223 | { | |
224 | return $this->_total; | |
225 | } | |
226 | ||
227 | public function next() | |
228 | { | |
229 | ++$this->pos; | |
230 | $entry = $this->heap->pop(); | |
231 | if (is_null($entry)) { | |
232 | return null; | |
233 | } | |
234 | if ($this->preComputed) { | |
235 | return $entry['value']; | |
236 | } | |
237 | $it = $entry['it']; | |
238 | $item = $this->iterators[$it]->next(); | |
239 | if (!is_null($item)) { | |
240 | $this->heap->push(array('it' => $it, 'value' => $item)); | |
241 | } | |
242 | return $entry['value']; | |
243 | } | |
244 | ||
245 | public function last() | |
246 | { | |
247 | return $this->heap->count() == 0; | |
248 | } | |
249 | ||
250 | public function first() | |
251 | { | |
252 | return $this->pos == 1; | |
253 | } | |
254 | } | |
255 | ||
63f00a3f FB |
256 | // vim:set et sw=4 sts=4 sws=4 foldmethod=marker enc=utf-8: |
257 | ?> |