| 1 | <?php |
| 2 | /*************************************************************************** |
| 3 | * Copyright (C) 2003-2010 Polytechnique.org * |
| 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 | |
| 22 | class PlIteratorUtils |
| 23 | { |
| 24 | /** Builds a new empty iterator |
| 25 | */ |
| 26 | public static function emptyIterator() |
| 27 | { |
| 28 | return new PlEmptyIterator(); |
| 29 | } |
| 30 | |
| 31 | /** Build an iterator over an array. |
| 32 | * @param array The array. |
| 33 | * @param depth The depth of iteration. |
| 34 | * @return an iterator that return entries in the form |
| 35 | * array(key => array(0 => key_for_depth0 [, 1 => key_for_depths1, ...]), |
| 36 | * value => the value); |
| 37 | */ |
| 38 | public static function fromArray(array $array, $depth = 1, $flat = false) |
| 39 | { |
| 40 | return new PlArrayIterator($array, $depth, $flat); |
| 41 | } |
| 42 | |
| 43 | |
| 44 | /** Sort an iterator using the given sort callback. |
| 45 | * @param iterator The iterator to sort. |
| 46 | * @param callback The callback for comparison. |
| 47 | * @return a new iterator with the entries sorted. |
| 48 | */ |
| 49 | public static function sort(PlIterator $iterator, $callback) |
| 50 | { |
| 51 | $heap = new PlHeap($callback); |
| 52 | while ($item = $iterator->next()) { |
| 53 | $heap->push($item); |
| 54 | } |
| 55 | return $heap->iterator(); |
| 56 | } |
| 57 | |
| 58 | |
| 59 | /** Merge several iterator into a unique one. |
| 60 | * @param iterators Array of iterators. |
| 61 | * @param callback The callback for comparison. |
| 62 | * @param sorted Tell wether the iterators are already sorted using the given callback. |
| 63 | * @return an iterator. |
| 64 | */ |
| 65 | public static function merge(array $iterators, $callback, $sorted = true) |
| 66 | { |
| 67 | return new PlMergeIterator($iterators, $callback, $sorted); |
| 68 | } |
| 69 | |
| 70 | |
| 71 | /** Build an iterator that contains only the elements of the given iterator that |
| 72 | * match the given condition. The condition should be a callback that takes an element |
| 73 | * and returns a boolean. |
| 74 | * @param iterator The source iterator |
| 75 | * @param callback The condition |
| 76 | * @return an iterator |
| 77 | */ |
| 78 | public static function filter(PlIterator $iterator, $callback) |
| 79 | { |
| 80 | return new PlFilterIterator($iterator, $callback); |
| 81 | } |
| 82 | |
| 83 | |
| 84 | /** Build an iterator that transforms the element of another iterator. The callback |
| 85 | * takes an element and transform it into another one. Be careful: if the result |
| 86 | * of the callback is null, the iteration ends. |
| 87 | * @param iterator The source iterator |
| 88 | * @param callback The transformer. |
| 89 | */ |
| 90 | public static function map(PlIterator $iterator, $callback) |
| 91 | { |
| 92 | return new PlMapIterator($iterator, $callback); |
| 93 | } |
| 94 | |
| 95 | /** Build an iterator whose values are iterators too; such a 'subIterator' will end |
| 96 | * when the value of $callback changes; |
| 97 | * WARNING: will fast-forward the current subiterator until it is over ! |
| 98 | * @param iterator The source iterator |
| 99 | * @param callback The callback for detecting changes. XXX: Might be called twice on a given object |
| 100 | * @return an iterator |
| 101 | */ |
| 102 | public static function subIterator(PlIterator $iterator, $callback) |
| 103 | { |
| 104 | return new PlSubIterator($iterator, $callback); |
| 105 | } |
| 106 | |
| 107 | /** Build an iterator that will iterate over the given set of iterators, returning consistent |
| 108 | * sets of values (i.e only the values for which the result of the callback is the same as that |
| 109 | * for the master) |
| 110 | * @param iterators The set of iterators |
| 111 | * @param callbacks A list of callbacks (one for each iterator), or a single, common, callback |
| 112 | * @param master The id of the "master" iterator in the first list |
| 113 | */ |
| 114 | public static function parallelIterator(array $iterators, $callbacks, $master) |
| 115 | { |
| 116 | return new PlParallelIterator($iterators, $callbacks, $master); |
| 117 | } |
| 118 | |
| 119 | /** Returns the callback for '$x -> $x[$key]'; |
| 120 | * @param $key the index to retrieve in arrays |
| 121 | * @return a callback |
| 122 | */ |
| 123 | public static function arrayValueCallback($key) |
| 124 | { |
| 125 | $callback = new _GetArrayValueCallback($key); |
| 126 | return array($callback, 'get'); |
| 127 | } |
| 128 | |
| 129 | /** Returns the callback for '$x -> $x->prop'; |
| 130 | * @param $property The property to retrieve |
| 131 | * @return a callback |
| 132 | */ |
| 133 | public static function objectPropertyCallback($property) |
| 134 | { |
| 135 | $callback = new _GetObjectPropertyCallback($property); |
| 136 | return array($callback, 'get'); |
| 137 | } |
| 138 | } |
| 139 | |
| 140 | /** Empty iterator |
| 141 | */ |
| 142 | class PlEmptyIterator implements PlIterator |
| 143 | { |
| 144 | public function first() |
| 145 | { |
| 146 | return false; |
| 147 | } |
| 148 | |
| 149 | public function last() |
| 150 | { |
| 151 | return false; |
| 152 | } |
| 153 | |
| 154 | public function next() |
| 155 | { |
| 156 | return null; |
| 157 | } |
| 158 | |
| 159 | public function total() |
| 160 | { |
| 161 | return 0; |
| 162 | } |
| 163 | } |
| 164 | |
| 165 | /** Iterates over an array. |
| 166 | */ |
| 167 | class PlArrayIterator implements PlIterator |
| 168 | { |
| 169 | private $array; |
| 170 | private $depth; |
| 171 | |
| 172 | private $_its = array(); |
| 173 | |
| 174 | private $_total; |
| 175 | private $_first; |
| 176 | private $_last; |
| 177 | private $_pos; |
| 178 | private $_flat; |
| 179 | |
| 180 | public function __construct(array &$array, $depth = 1, $flat = false) |
| 181 | { |
| 182 | $this->array =& $array; |
| 183 | $this->depth = $depth; |
| 184 | $this->_total = $this->count($array, $depth - 1); |
| 185 | $this->_pos = 0; |
| 186 | $this->_first = false; |
| 187 | $this->_last = false; |
| 188 | $this->_flat = $flat; |
| 189 | |
| 190 | for ($i = 0 ; $i < $depth ; ++$i) { |
| 191 | if ($i == 0) { |
| 192 | $this->_its[] = $array; |
| 193 | } else { |
| 194 | $this->_its[] = current($this->_its[$i - 1]); |
| 195 | } |
| 196 | reset($this->_its[$i]); |
| 197 | } |
| 198 | } |
| 199 | |
| 200 | private function count(array &$array, $depth) |
| 201 | { |
| 202 | if ($depth == 0) { |
| 203 | return count($array); |
| 204 | } else { |
| 205 | $sum = 0; |
| 206 | foreach ($array as &$item) { |
| 207 | $sum += $this->count($item, $depth - 1); |
| 208 | } |
| 209 | return $sum; |
| 210 | } |
| 211 | } |
| 212 | |
| 213 | private function nextArray($depth) |
| 214 | { |
| 215 | if ($depth == 0) { |
| 216 | return; |
| 217 | } |
| 218 | $this->_its[$depth] = next($this->_its[$depth - 1]); |
| 219 | if ($this->_its[$depth] === false) { |
| 220 | $this->nextArray($depth - 1); |
| 221 | if ($this->_its[$depth - 1] === false) { |
| 222 | return; |
| 223 | } |
| 224 | $this->_its[$depth] = current($this->_its[$depth - 1]); |
| 225 | } |
| 226 | reset($this->_its[$depth]); |
| 227 | } |
| 228 | |
| 229 | public function next() |
| 230 | { |
| 231 | ++$this->_pos; |
| 232 | $this->_first = ($this->_total > 0 && $this->_pos == 1); |
| 233 | $this->_last = ($this->_pos == $this->_total); |
| 234 | if ($this->_pos > $this->_total) { |
| 235 | return null; |
| 236 | } |
| 237 | |
| 238 | $val = current($this->_its[$this->depth - 1]); |
| 239 | if ($val === false) { |
| 240 | $this->nextArray($this->depth - 1); |
| 241 | $val = current($this->_its[$this->depth - 1]); |
| 242 | if ($val === false) { |
| 243 | return null; |
| 244 | } |
| 245 | } |
| 246 | $keys = array(); |
| 247 | for ($i = 0 ; $i < $this->depth ; ++$i) { |
| 248 | $keys[] = key($this->_its[$i]); |
| 249 | } |
| 250 | next($this->_its[$this->depth - 1]); |
| 251 | if ($this->_flat) { |
| 252 | return $val; |
| 253 | } else { |
| 254 | return array('keys' => $keys, |
| 255 | 'value' => $val); |
| 256 | } |
| 257 | } |
| 258 | |
| 259 | public function total() |
| 260 | { |
| 261 | return $this->_total; |
| 262 | } |
| 263 | |
| 264 | public function first() |
| 265 | { |
| 266 | return $this->_first; |
| 267 | } |
| 268 | |
| 269 | public function last() |
| 270 | { |
| 271 | return $this->_last; |
| 272 | } |
| 273 | } |
| 274 | |
| 275 | |
| 276 | /** Iterator that return the result of a merge of several iterators. |
| 277 | */ |
| 278 | class PlMergeIterator implements PlIterator |
| 279 | { |
| 280 | /* The heap is field with entries with the form: |
| 281 | * array('it' => id of the iterator this entry come from, |
| 282 | * 'value' => value of the entry). |
| 283 | */ |
| 284 | private $heap; |
| 285 | private $preComputed = false; |
| 286 | private $comparator; |
| 287 | private $iterators; |
| 288 | private $_total; |
| 289 | private $pos; |
| 290 | |
| 291 | public function __construct(array $iterators, $callback, $sorted = true) |
| 292 | { |
| 293 | $this->heap = new PlHeap(array($this, 'compare')); |
| 294 | $this->_total = 0; |
| 295 | $this->comparator = $callback; |
| 296 | if ($sorted) { |
| 297 | $this->iterators = $iterators; |
| 298 | foreach ($this->iterators as $key => &$it) { |
| 299 | $this->_total += $it->total(); |
| 300 | $item = $it->next(); |
| 301 | if (!is_null($item)) { |
| 302 | $this->heap->push(array('it' => $key, 'value' => $item)); |
| 303 | } |
| 304 | } |
| 305 | } else { |
| 306 | $this->preComputed = true; |
| 307 | foreach ($iterators as $key => &$it) { |
| 308 | $this->_total += $it->total(); |
| 309 | while (!is_null($item = $it->next())) { |
| 310 | $this->heap->push(array('it' => $key, 'value' => $item)); |
| 311 | } |
| 312 | } |
| 313 | } |
| 314 | $this->pos = 0; |
| 315 | } |
| 316 | |
| 317 | /** Compare two entries of the heap using the comparator of the user. |
| 318 | */ |
| 319 | public function compare($a, $b) |
| 320 | { |
| 321 | $cp = call_user_func($this->comparator, $a['value'], $b['value']); |
| 322 | if ($cp == 0) { |
| 323 | return $a['it'] - $b['it']; |
| 324 | } |
| 325 | return $cp; |
| 326 | } |
| 327 | |
| 328 | public function total() |
| 329 | { |
| 330 | return $this->_total; |
| 331 | } |
| 332 | |
| 333 | public function next() |
| 334 | { |
| 335 | ++$this->pos; |
| 336 | $entry = $this->heap->pop(); |
| 337 | if (is_null($entry)) { |
| 338 | return null; |
| 339 | } |
| 340 | if ($this->preComputed) { |
| 341 | return $entry['value']; |
| 342 | } |
| 343 | $it = $entry['it']; |
| 344 | $item = $this->iterators[$it]->next(); |
| 345 | if (!is_null($item)) { |
| 346 | $this->heap->push(array('it' => $it, 'value' => $item)); |
| 347 | } |
| 348 | return $entry['value']; |
| 349 | } |
| 350 | |
| 351 | public function last() |
| 352 | { |
| 353 | return $this->heap->count() == 0; |
| 354 | } |
| 355 | |
| 356 | public function first() |
| 357 | { |
| 358 | return $this->pos == 1; |
| 359 | } |
| 360 | } |
| 361 | |
| 362 | |
| 363 | class PlFilterIterator implements PlIterator |
| 364 | { |
| 365 | private $pos; |
| 366 | private $source; |
| 367 | private $callback; |
| 368 | private $element; |
| 369 | |
| 370 | public function __construct(PlIterator $source, $callback) |
| 371 | { |
| 372 | $this->source = $source; |
| 373 | $this->callback = $callback; |
| 374 | $this->pos = 0; |
| 375 | $this->element = $this->fetchNext(); |
| 376 | } |
| 377 | |
| 378 | private function fetchNext() |
| 379 | { |
| 380 | do { |
| 381 | $current = $this->source->next(); |
| 382 | if (is_null($current) || call_user_func($this->callback, $current)) { |
| 383 | return $current; |
| 384 | } |
| 385 | } while (true); |
| 386 | } |
| 387 | |
| 388 | public function next() |
| 389 | { |
| 390 | ++$this->pos; |
| 391 | $elt = $this->element; |
| 392 | if (!is_null($this->element)) { |
| 393 | $this->element = $this->fetchNext(); |
| 394 | } |
| 395 | return $elt; |
| 396 | } |
| 397 | |
| 398 | public function total() |
| 399 | { |
| 400 | /* This is an approximation since the correct total |
| 401 | * cannot be computed without fetching all the elements |
| 402 | */ |
| 403 | return $this->source->total(); |
| 404 | } |
| 405 | |
| 406 | public function first() |
| 407 | { |
| 408 | return $this->pos == 1; |
| 409 | } |
| 410 | |
| 411 | public function last() |
| 412 | { |
| 413 | return is_null($this->element); |
| 414 | } |
| 415 | } |
| 416 | |
| 417 | |
| 418 | class PlMapIterator implements PlIterator |
| 419 | { |
| 420 | private $source; |
| 421 | private $callback; |
| 422 | |
| 423 | public function __construct(PlIterator $source, $callback) |
| 424 | { |
| 425 | $this->source = $source; |
| 426 | $this->callback = $callback; |
| 427 | } |
| 428 | |
| 429 | public function next() |
| 430 | { |
| 431 | $elt = $this->source->next(); |
| 432 | if ($elt) { |
| 433 | return call_user_func($this->callback, $elt); |
| 434 | } else { |
| 435 | return null; |
| 436 | } |
| 437 | } |
| 438 | |
| 439 | public function total() |
| 440 | { |
| 441 | return $this->source->total(); |
| 442 | } |
| 443 | |
| 444 | public function first() |
| 445 | { |
| 446 | return $this->source->first(); |
| 447 | } |
| 448 | |
| 449 | public function last() |
| 450 | { |
| 451 | return $this->source->last(); |
| 452 | } |
| 453 | } |
| 454 | |
| 455 | class PlSubIterator implements PlIterator |
| 456 | { |
| 457 | private $source; |
| 458 | private $callback; |
| 459 | private $next = null; // The next item, if it has been fetched too early by a subiterator |
| 460 | private $pos = 0; |
| 461 | private $sub = null; |
| 462 | |
| 463 | public function __construct(PlIterator $source, $callback) |
| 464 | { |
| 465 | $this->source = $source; |
| 466 | $this->callback = $callback; |
| 467 | } |
| 468 | |
| 469 | /** WARNING: this will "fast-forward" the subiterator to its end |
| 470 | */ |
| 471 | public function next() |
| 472 | { |
| 473 | if ($this->last()) { |
| 474 | return null; |
| 475 | } else { |
| 476 | if ($this->sub != null) { |
| 477 | while (!$this->sub->last()) { |
| 478 | $this->sub->next(); |
| 479 | } |
| 480 | } |
| 481 | |
| 482 | if ($this->last()) { |
| 483 | return null; |
| 484 | } |
| 485 | |
| 486 | ++$this->pos; |
| 487 | $this->sub = new PlInnerSubIterator($this->source, $this->callback, $this, $this->next); |
| 488 | return $this->sub; |
| 489 | } |
| 490 | } |
| 491 | |
| 492 | /** This will always be a too big number, but the actual result can't be easily computed |
| 493 | */ |
| 494 | public function total() |
| 495 | { |
| 496 | return $this->source->total(); |
| 497 | } |
| 498 | |
| 499 | /** This will only return true if the current subiterator was the last one, |
| 500 | * and if it has been fully used |
| 501 | */ |
| 502 | public function last() |
| 503 | { |
| 504 | if ($this->sub != null && !$this->sub->last()) { |
| 505 | return false; |
| 506 | } |
| 507 | return ($this->source->last() && $this->next == null); |
| 508 | } |
| 509 | |
| 510 | public function first() |
| 511 | { |
| 512 | return $this->pos == 1; |
| 513 | } |
| 514 | |
| 515 | // Called by a subiterator to "rewind" the core iterator |
| 516 | public function setNext($item) |
| 517 | { |
| 518 | $this->next = $item; |
| 519 | } |
| 520 | } |
| 521 | |
| 522 | class PlInnerSubIterator implements PlIterator |
| 523 | { |
| 524 | private $source; |
| 525 | private $callback; |
| 526 | private $parent; |
| 527 | |
| 528 | private $next; // Not null if the source has to be "rewinded" |
| 529 | |
| 530 | private $curval = null; |
| 531 | private $curelt = null; |
| 532 | private $val = null; |
| 533 | private $pos = 0; |
| 534 | private $stepped = false; |
| 535 | private $over = false; |
| 536 | |
| 537 | public function __construct(PlIterator $source, $callback, PlSubIterator $parent, $next = null) |
| 538 | { |
| 539 | $this->source = $source; |
| 540 | $this->callback = $callback; |
| 541 | $this->parent = $parent; |
| 542 | $this->next = $next; |
| 543 | $this->parent->setNext(null); |
| 544 | } |
| 545 | |
| 546 | public function value() |
| 547 | { |
| 548 | $this->_step(); |
| 549 | return $this->curval; |
| 550 | } |
| 551 | |
| 552 | // Move one step, if the current element has been used |
| 553 | private function _step() |
| 554 | { |
| 555 | if ($this->stepped) { |
| 556 | return; |
| 557 | } |
| 558 | |
| 559 | if ($this->next != null) { |
| 560 | $this->curelt = $this->next; |
| 561 | $this->next = null; |
| 562 | } else { |
| 563 | if ($this->source->last()) { |
| 564 | $this->over = true; |
| 565 | return; |
| 566 | } |
| 567 | $this->curelt = $this->source->next(); |
| 568 | } |
| 569 | |
| 570 | if ($this->pos == 0) { |
| 571 | $this->val = call_user_func($this->callback, $this->curelt); |
| 572 | $this->curval = $this->val; |
| 573 | } else { |
| 574 | $this->curval = call_user_func($this->callback, $this->curelt); |
| 575 | } |
| 576 | |
| 577 | $this->stepped = true; |
| 578 | } |
| 579 | |
| 580 | public function next() |
| 581 | { |
| 582 | if ($this->over) { |
| 583 | return null; |
| 584 | } |
| 585 | |
| 586 | $this->_step(); |
| 587 | |
| 588 | if ($this->over) { |
| 589 | return null; |
| 590 | } |
| 591 | |
| 592 | ++$this->pos; |
| 593 | $this->stepped = false; |
| 594 | |
| 595 | if ($this->val == $this->curval) { |
| 596 | return $this->curelt; |
| 597 | } |
| 598 | |
| 599 | $this->parent->setNext($this->curelt); |
| 600 | $this->over = true; |
| 601 | return null; |
| 602 | } |
| 603 | |
| 604 | /** This will always be a too big number, but the actual result can't be easily computed |
| 605 | */ |
| 606 | public function total() |
| 607 | { |
| 608 | return $this->source->total(); |
| 609 | } |
| 610 | |
| 611 | public function last() |
| 612 | { |
| 613 | if ($this->over) { |
| 614 | return true; |
| 615 | } |
| 616 | $this->_step(); |
| 617 | return $this->over || ($this->val != $this->curval); |
| 618 | } |
| 619 | |
| 620 | public function first() |
| 621 | { |
| 622 | return $this->pos == 1; |
| 623 | } |
| 624 | |
| 625 | } |
| 626 | |
| 627 | /** Builds an iterator over a set of iterators, from which one is given as 'master'; |
| 628 | * The arguments are : |
| 629 | * - An array of iterators, to iterate simultaneously |
| 630 | * - An array of callbacks (one attached to each iterator), or a single callback (to |
| 631 | * use for all iterators) |
| 632 | * - The id of the 'master' iterator |
| 633 | * |
| 634 | * This ParallelIterator will iterate over the iterators, and, at each |
| 635 | * step of the master iterator, it will apply the callbacks to the corresponding |
| 636 | * iterators and return the values of the "slaves" for which the callback returned the |
| 637 | * same value as the callback of the master. |
| 638 | * |
| 639 | * The callback should compute some kind of index, and never return the same value |
| 640 | * twice for a given iterator |
| 641 | * |
| 642 | * It is assumed that, if the callback for a slave doesn't have the same value |
| 643 | * as the value for the master, this means that there is a "hole" in the values |
| 644 | * of that slave. |
| 645 | * |
| 646 | * Example : |
| 647 | * - The callback is 'get the first cell' |
| 648 | * - The master is : |
| 649 | * [0, 1], [1, 13], [2, 42] |
| 650 | * - The first slave (slave1) is : |
| 651 | * [0, 'a'], [2, 'b'] |
| 652 | * - The second slave (slave2) is : |
| 653 | * [1, 42], [2, 0] |
| 654 | * The resulting iterator would yield : |
| 655 | * - array(master => [0, 1], slave1 => [0, 'a'], slave2 => null) |
| 656 | * - array(master => [1, 13], slave1 => null, slave2 => [1, 42]) |
| 657 | * - array(master => [2, 42], slave1 => [1, 'b'], slave2 => [2, 0]) |
| 658 | */ |
| 659 | class PlParallelIterator implements PlIterator |
| 660 | { |
| 661 | private $iterators; |
| 662 | private $ids; |
| 663 | private $callbacks; |
| 664 | |
| 665 | private $master_id; |
| 666 | private $master; |
| 667 | |
| 668 | private $over = array(); |
| 669 | private $stepped = array(); |
| 670 | private $current_elts = array(); |
| 671 | private $callback_res = array(); |
| 672 | |
| 673 | public function __construct(array $iterators, $callbacks, $master) |
| 674 | { |
| 675 | $this->iterators = $iterators; |
| 676 | $this->master_id = $master; |
| 677 | $this->master = $iterators[$master]; |
| 678 | |
| 679 | $this->ids = array_keys($iterators); |
| 680 | |
| 681 | $v = array_values($callbacks); |
| 682 | if (is_array($v[0])) { |
| 683 | $this->callbacks = $callbacks; |
| 684 | } else { |
| 685 | $this->callbacks = array(); |
| 686 | foreach ($this->ids as $id) { |
| 687 | $this->callbacks[$id] = $callbacks; |
| 688 | } |
| 689 | } |
| 690 | |
| 691 | foreach ($this->ids as $id) { |
| 692 | $this->stepped[$id] = false; |
| 693 | $this->over[$id] = false; |
| 694 | $this->current_elts[$id] = null; |
| 695 | $this->callback_res[$id] = null; |
| 696 | } |
| 697 | } |
| 698 | |
| 699 | private function step($id) |
| 700 | { |
| 701 | if ($this->stepped[$id]) { |
| 702 | return; |
| 703 | } |
| 704 | |
| 705 | // Don't do anything if the iterator is at its end |
| 706 | if ($this->over[$id]) { |
| 707 | $this->stepped[$id] = true; |
| 708 | return; |
| 709 | } |
| 710 | |
| 711 | $it = $this->iterators[$id]; |
| 712 | $nxt = $it->next(); |
| 713 | $this->stepped[$id] = true; |
| 714 | if ($nxt === null) { |
| 715 | $this->over[$id] = true; |
| 716 | $this->current_elts[$id] = null; |
| 717 | $this->callback_res[$id] = null; |
| 718 | return; |
| 719 | } |
| 720 | $res = call_user_func($this->callbacks[$id], $nxt); |
| 721 | $this->current_elts[$id] = $nxt; |
| 722 | $this->callback_res[$id] = $res; |
| 723 | } |
| 724 | |
| 725 | private function stepAll() |
| 726 | { |
| 727 | foreach ($this->ids as $id) { |
| 728 | $this->step($id); |
| 729 | } |
| 730 | } |
| 731 | |
| 732 | public function next() |
| 733 | { |
| 734 | $this->stepAll(); |
| 735 | if ($this->current_elts[$this->master_id] === null) { |
| 736 | return null; |
| 737 | } |
| 738 | |
| 739 | $res = array(); |
| 740 | $master = $this->callback_res[$this->master_id]; |
| 741 | foreach ($this->ids as $id) { |
| 742 | if ($this->callback_res[$id] == $master) { |
| 743 | $res[$id] = $this->current_elts[$id]; |
| 744 | $this->stepped[$id] = false; |
| 745 | } else { |
| 746 | $res[$id] = null; |
| 747 | } |
| 748 | } |
| 749 | |
| 750 | return $res; |
| 751 | } |
| 752 | |
| 753 | public function first() |
| 754 | { |
| 755 | return $this->master->first(); |
| 756 | } |
| 757 | |
| 758 | public function total() |
| 759 | { |
| 760 | return $this->master->total(); |
| 761 | } |
| 762 | |
| 763 | public function last() |
| 764 | { |
| 765 | return $this->master->last(); |
| 766 | } |
| 767 | } |
| 768 | |
| 769 | // Wrapper class for 'arrayValueCallback' (get field $key of the given array) |
| 770 | class _GetArrayValueCallback |
| 771 | { |
| 772 | private $key; |
| 773 | |
| 774 | public function __construct($key) |
| 775 | { |
| 776 | $this->key = $key; |
| 777 | } |
| 778 | |
| 779 | public function get(array $arr) |
| 780 | { |
| 781 | if (array_key_exists($this->key, $arr)) { |
| 782 | return $arr[$this->key]; |
| 783 | } else { |
| 784 | return null; |
| 785 | } |
| 786 | } |
| 787 | } |
| 788 | |
| 789 | // Wrapper class for 'objectPropertyCallback' (get property ->$blah of the given object) |
| 790 | class _GetObjectPropertyCallback |
| 791 | { |
| 792 | private $property; |
| 793 | |
| 794 | public function __construct($property) |
| 795 | { |
| 796 | $this->property = $property; |
| 797 | } |
| 798 | |
| 799 | public function get($obj) |
| 800 | { |
| 801 | $p = $this->property; |
| 802 | return @$obj->$p; |
| 803 | } |
| 804 | } |
| 805 | |
| 806 | // vim:set et sw=4 sts=4 sws=4 foldmethod=marker enc=utf-8: |
| 807 | ?> |