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<?php |
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/* |
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* The MIT License (MIT) |
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* Copyright © 2017 Marcos Lois Bermudez <[email protected]> |
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* * |
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* Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated |
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* documentation files (the “Software”), to deal in the Software without restriction, including without limitation |
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* the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, |
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* and to permit persons to whom the Software is furnished to do so, subject to the following conditions: |
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* * |
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* The above copyright notice and this permission notice shall be included in all copies or substantial portions |
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* of the Software. |
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* * |
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* THE SOFTWARE IS PROVIDED “AS IS”, WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED |
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* TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL |
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* THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF |
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* CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER |
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* DEALINGS IN THE SOFTWARE. |
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*/ |
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namespace TTIC\Commons\Iterator; |
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use Iterator; |
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class SyncOrderedIterator implements Iterator |
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{ |
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const LEFT_MISSING = 'left-missing'; |
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const RIGHT_MISSING = 'right-missing'; |
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const EQUAL = 'equal'; |
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const NOT_EQUAL = 'not-equal'; |
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/** |
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* Left side iterator |
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* @var Iterator |
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*/ |
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protected $left; |
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/** |
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* Right side iterator |
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* @var Iterator |
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*/ |
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protected $right; |
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/** |
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* Current operation |
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* @var mixed |
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*/ |
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protected $operation; |
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/** |
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* @var int |
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*/ |
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protected $key = 0; |
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/** |
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* @var callable |
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*/ |
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protected $keyCmpCallback; |
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/** |
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* @var callable |
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*/ |
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protected $valueEqualsCallback; |
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/** |
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* SyncOrderedIterator constructor. |
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* |
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* @param Iterator $left |
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* @param Iterator $right |
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*/ |
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public function __construct(Iterator $left, Iterator $right, |
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callable $keyCmpCallback = null, callable $valueEqualsCallback = null) |
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{ |
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$this->left = $left; |
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$this->right = $right; |
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$this->keyCmpCallback = $keyCmpCallback; |
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$this->valueEqualsCallback = $valueEqualsCallback; |
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} |
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/** |
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* Return the current element |
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* @link http://php.net/manual/en/iterator.current.php |
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* @return mixed Can return any type. |
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* @since 5.0.0 |
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*/ |
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public function current() |
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{ |
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return $this->operation; |
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} |
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/** |
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* Move forward to next element |
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* @link http://php.net/manual/en/iterator.next.php |
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* @return void Any returned value is ignored. |
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* @since 5.0.0 |
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*/ |
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public function next() |
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{ |
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$left = $this->left; |
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$right = $this->right; |
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$this->operation = null; |
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if (($left->valid() || $right->valid())) { |
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if (!$left->valid()) { |
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// If left is exausted |
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$this->operation = $this->getOperation(self::LEFT_MISSING); |
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$right->next(); |
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return; |
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} |
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if (!$right->valid()) { |
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// If right is exausted |
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$this->operation = $this->getOperation(self::RIGHT_MISSING); |
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$left->next(); |
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return; |
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} |
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// Compare items |
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if ($callback = $this->keyCmpCallback) { |
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$cmp = $callback($left, $right); |
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} else { |
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$lItem = $left->current(); |
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$rItem = $right->current(); |
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$cmp = ($lItem === $rItem ? 0 : (($lItem < $rItem) ? -1 : 1)); |
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} |
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// Create operations |
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if ($cmp < 0) { |
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// If left precedes right |
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$this->operation = $this->getOperation(self::RIGHT_MISSING); |
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$left->next(); |
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return; |
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} |
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if ($cmp > 0) { |
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// right precedes left |
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$this->operation = $this->getOperation(self::LEFT_MISSING); |
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$right->next(); |
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return; |
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} |
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// Equal items |
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$equals = ($callback = $this->valueEqualsCallback) ? $callback($left, $right) : true; |
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$this->operation = $this->getOperation($equals ? self::EQUAL : self::NOT_EQUAL); |
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$left->next(); |
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$right->next(); |
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} |
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} |
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/** |
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* Return the key of the current element |
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* @link http://php.net/manual/en/iterator.key.php |
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* @return mixed scalar on success, or null on failure. |
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* @since 5.0.0 |
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*/ |
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public function key() |
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{ |
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return $this->key; |
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} |
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/** |
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* Checks if current position is valid |
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* @link http://php.net/manual/en/iterator.valid.php |
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* @return boolean The return value will be casted to boolean and then evaluated. |
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* Returns true on success or false on failure. |
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* @since 5.0.0 |
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*/ |
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public function valid() |
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{ |
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return (bool) $this->operation; |
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} |
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/** |
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* Rewind the Iterator to the first element |
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* @link http://php.net/manual/en/iterator.rewind.php |
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* @return void Any returned value is ignored. |
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* @since 5.0.0 |
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*/ |
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public function rewind() |
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{ |
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$this->left->rewind(); |
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$this->right->rewind(); |
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$this->key = -1; |
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$this->next(); |
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} |
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/** |
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* Creates a operation for sync |
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* @param $operation string |
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* @return array|null |
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*/ |
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protected function getOperation($operation) { |
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$op = [ 'type' => $operation ]; |
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switch ($operation) { |
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case self::LEFT_MISSING: |
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$op['item'] = [ |
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'key' => $this->right->key(), |
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'value' => $this->right->current() |
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]; |
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break; |
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case self::RIGHT_MISSING: |
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$op['item'] = [ |
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'key' => $this->left->key(), |
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'value' => $this->left->current() |
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]; |
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break; |
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case self::EQUAL: |
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case self::NOT_EQUAL: |
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$op['left'] = [ |
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'key' => $this->left->key(), |
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'value' => $this->left->current() |
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]; |
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$op['right'] = [ |
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'key' => $this->right->key(), |
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'value' => $this->right->current() |
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]; |
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break; |
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} |
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$this->key++; |
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return $op; |
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} |
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} |
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