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<?php |
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namespace Gielfeldt\Iterators; |
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class OrderedInterleaveIterator extends \SplHeap |
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{ |
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const DEFAULT_COMPARE = [__CLASS__, 'defaultCompare']; |
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protected $iterators; |
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protected $compareFunction = self::DEFAULT_COMPARE; |
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public function __construct(\Traversable ...$iterators) |
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{ |
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$this->iterators = new \ArrayIterator(); |
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foreach ($iterators as $iterator) { |
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$this->add($iterator); |
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} |
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} |
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public function setCompare($compareFunction) |
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{ |
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$this->compareFunction = $compareFunction; |
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return $this; |
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} |
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public function compare($a, $b) |
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{ |
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return call_user_func_array($this->compareFunction, [$b[2], $a[2]]); |
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} |
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public function defaultCompare($a, $b) |
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{ |
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return $a <=> $b; |
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} |
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public function add(\Traversable $iterator) |
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{ |
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$this->iterators->append($iterator instanceof \Iterator ? $iterator : new \IteratorIterator($iterator)); |
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return $this; |
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} |
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public function rewind() |
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{ |
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while (!$this->isEmpty()) { |
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$this->extract(); |
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} |
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foreach ($this->iterators as $no => $iterator) { |
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$iterator->rewind(); |
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if ($iterator->valid()) { |
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$this->insert([$no, $iterator->key(), $iterator->current()]); |
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$iterator->next(); |
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} |
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} |
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$this->idx = 0; |
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} |
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public function key() |
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{ |
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return $this->top()[1]; |
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} |
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public function current() |
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{ |
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return $this->top()[2]; |
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} |
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public function next() |
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{ |
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$this->idx++; |
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$used = $this->extract(); |
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$no = $used[0]; |
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if ($this->iterators[$no]->valid()) { |
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$this->insert([$no, $this->iterators[$no]->key(), $this->iterators[$no]->current()]); |
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$this->iterators[$no]->next(); |
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} |
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} |
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} |
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gielfeldt /
iterators
In PHP it is possible to write to properties without declaring them. For example, the following is perfectly valid PHP code:
Generally, it is a good practice to explictly declare properties to avoid accidental typos and provide IDE auto-completion: