- MFH Add MultipleIterator (http://blog.somabo.de/2008/01/multipleiterator-for-php.html)

ext/spl/examples/multipleiterator.inc

@@ -0,0 +1,223 @@
+<?php
+/** @file multipleiterator.inc
+ * @ingroup Examples
+ * @brief class MultipleIterator
+ * @author  Johannes Schlueter
+ * @author  Marcus Boerger
+ * @date    2008
+ *
+ * SPL - Standard PHP Library
+ */
+
+/** @ingroup Examples
+ * @brief   Iterator that iterates over several iterators one after the other
+ * @author  Johannes Schlueter
+ * @author  Marcus Boerger
+ * @version 1.0
+ * @since PHP 5.3
+ */
+class MultipleIterator implements Iterator
+{
+	/** Inner Iterators */
+	private $iterators;
+
+	/** Flags: const MIT_* */
+	private $flags;
+
+	/** do not require all sub iterators to be valid in iteration */
+	const MIT_NEED_ANY = 0;
+
+	/** require all sub iterators to be valid in iteration */
+	const MIT_NEED_ALL  = 1;
+
+	/** keys are created from sub iterators position */
+	const MIT_KEYS_NUMERIC  = 0;
+
+	/** keys are created from sub iterators associated infromation */
+	const MIT_KEYS_ASSOC  = 2;
+
+	/** Construct a new empty MultipleIterator
+	* @param flags MIT_* flags
+	*/
+	public function __construct($flags = self::MIT_NEED_ALL|self::MIT_KEYS_NUMERIC)
+	{
+		$this->iterators = new SplObjectStorage();
+		$this->flags = $flags;
+	}
+
+	/** @return current flags MIT_* */
+	public function getFlags()
+	{
+		return $this->flags;
+	}
+
+	/** @param $flags new flags. */
+	public function setFlags($flags)
+	{
+		$this->flags = $flags;
+	}
+
+	/** @param $iter new Iterator to attach.
+	* @param $inf associative info forIteraotr, must be NULL, integer or string
+	*
+	* @throws IllegalValueException if a inf is none of NULL, integer or string
+	* @throws IllegalValueException if a inf is already an associated info
+	*/
+	public function attachIterator(Iterator $iter, $inf = NULL)
+	{
+
+		if (!is_null($inf))
+		{
+			if (!is_int($inf) && !is_string($inf))
+			{
+				throw new IllegalValueException('Inf must be NULL, integer or string');
+			}
+			foreach($this->iterators as $iter)
+			{
+				if ($inf == $this->iterators->getInfo())
+				{
+					throw new IllegalValueException('Key duplication error');
+				}
+			}
+		}
+		$this->iterators->attach($iter, $inf);
+	}
+
+	/** @param $iter attached Iterator that should be detached. */
+	public function detachIterator(Iterator $iter)
+	{
+		$this->iterators->detach($iter);
+	}
+
+	/** @param $iter Iterator to check
+	* @return whether $iter is attached or not
+	*/
+	public function containsIterator(Iterator $iter)
+	{
+		return $this->iterator->contains($iter);
+	}
+
+	/** @return number of attached Iterator instances. */
+	public function countIterators()
+	{
+		return $this->iterators->count();
+	}
+
+	/** Rewind all attached Iterator instances. */
+	public function rewind()
+	{
+		foreach($this->iterators as $iter)
+		{
+			$iter->rewind();
+		}
+	}
+
+	/**
+	* @return whether all or one sub iterator is valid depending on flags.
+	* In mode MIT_NEED_ALL we expect all sub iterators to be valid and
+	* return flase on the first non valid one. If that flag is not set we
+	* return true on the first valid sub iterator found. If no Iterator
+	* is attached, we always return false.
+	*/
+	public function valid()
+	{
+		if (!sizeof($this->iterators)) {
+			return false;
+		}
+		// The following code is an optimized version that executes as few
+		// valid() calls as necessary and that only checks the flags once.
+		$expect = $this->flags & self::MIT_NEED_ALL ? true : false;
+		foreach($this->iterators as $iter)
+		{
+			if ($expect != $iter->valid())
+			{
+				return !$expect;
+			}
+		}
+		return $expect;
+	}
+
+	/** Move all attached Iterator instances forward. That is invoke
+	* their next() method regardless of their state.
+	*/
+	public function next()
+	{
+		foreach($this->iterators as $iter)
+		{
+			$iter->next();
+		}
+	}
+
+	/** @return false if no sub Iterator is attached and an array of
+	* all registered Iterator instances current() result.
+	* @throws RuntimeException      if mode MIT_NEED_ALL is set and at least one
+	*                               attached Iterator is not valid().
+	* @throws IllegalValueException if a key is NULL and MIT_KEYS_ASSOC is set.
+	*/
+	public function current()
+	{
+		if (!sizeof($this->iterators))
+		{
+			return false;
+		}
+		$retval = array();
+		foreach($this->iterators as $iter)
+		{
+			if ($it->valid())
+			{
+				if ($this->flags & self::MIT_KEYS_ASSOC)
+				{
+					$key = $this->iterators->getInfo();
+					if (is_null($key))
+					{
+						throw new IllegalValueException('Sub-Iterator is associated with NULL');
+					}
+					$retval[$key] = $iter->current();
+				}
+				else
+				{
+					$retval[] = $iter->current();
+				}
+			}
+			else if ($this->flags & self::MIT_NEED_ALL)
+			{
+				throw new RuntimeException('Called current() with non valid sub iterator');
+			}
+			else
+			{
+				$retval[] = NULL;
+			}
+		}
+		return $retval;
+	}
+
+	/** @return false if no sub Iterator is attached and an array of
+	* all registered Iterator instances key() result.
+	* @throws LogicException if mode MIT_NEED_ALL is set and at least one
+	*         attached Iterator is not valid().
+	*/
+	public function key()
+	{
+		if (!sizeof($this->iterators))
+		{
+			return false;
+		}
+		$retval = array();
+		foreach($this->iterators as $iter)
+		{
+			if ($it->valid())
+			{
+				$retval[] = $iter->key();
+			}
+			else if ($this->flags & self::MIT_NEED_ALL)
+			{
+				throw new LogicException('Called key() with non valid sub iterator');
+			}
+			else
+			{
+				$retval[] = NULL;
+			}
+		}
+		return $retval;
+	}
+}