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75 lines
1.7 KiB
75 lines
1.7 KiB
<?php
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namespace SparkLib;
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use InvalidArgumentException;
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abstract class Iterator implements \Iterator {
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protected $_useCache = false;
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/**
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* Require that children of this class implement a getNext()
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*/
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abstract public function getNext ();
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/**
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* Should child classes attempt to use cached return values?
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*
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* It's up to a child to decide what, if anything, this means.
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*/
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public function useCache ($value = true)
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{
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$this->_useCache = $value;
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return $this;
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}
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/**
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* Calls $function() on each remaining element in the iterator.
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*
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* @param callback $function
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* @return SparkFriendFinder the finder
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*/
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public function each ($function)
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{
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if (! \is_callable($function) )
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throw new InvalidArgumentException('each(): parameter is not a callback');
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// handle first/current result
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$rec = $this->getNext();
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if (! $rec)
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return $this;
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call_user_func($function, $rec);
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// handle the rest, if any
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while ($this->valid()) {
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$rec = $this->getNext();
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if ($rec) {
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call_user_func($function, $rec);
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}
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}
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return $this;
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}
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/**
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* Map iterator results to an array, using a callback function.
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*
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* Dubiously, this cannot yet elide or combine elements, but it's
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* still somewhat useful.
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*
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* @param callback $function
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* @return array $results
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*/
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public function map ($function)
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{
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if (! \is_callable($function))
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throw new InvalidArgumentException('map(): parameter is not a callback.');
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$results = [];
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$this->each(function ($result) use ($function, &$results) {
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$results[] = call_user_func($function, $result);
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});
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return $results;
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}
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}
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