diff options
Diffstat (limited to 'framework')
| -rw-r--r-- | framework/Collections/TQueue.php | 253 |
1 files changed, 253 insertions, 0 deletions
diff --git a/framework/Collections/TQueue.php b/framework/Collections/TQueue.php new file mode 100644 index 00000000..2c75c48e --- /dev/null +++ b/framework/Collections/TQueue.php @@ -0,0 +1,253 @@ +<?php
+/**
+ * TQueue, TQueueIterator classes
+ *
+ * @author Qiang Xue <qiang.xue@gmail.com>
+ * @link http://www.pradosoft.com/
+ * @copyright Copyright © 2005 PradoSoft
+ * @license http://www.pradosoft.com/license/
+ * @version $Revision: $ $Date: $
+ * @package System.Collections
+ */
+
+/**
+ * TQueue class
+ *
+ * TQueue implements a queue.
+ *
+ * The typical queue operations are implemented, which include
+ * {@link enqueue()}, {@link dequeue()} and {@link peek()}. In addition,
+ * {@link contains()} can be used to check if an item is contained
+ * in the queue. To obtain the number of the items in the queue,
+ * check the {@link getCount Count} property.
+ *
+ * Items in the queue may be traversed using foreach as follows,
+ * <code>
+ * foreach($queue as $item) ...
+ * </code>
+ *
+ * @author Qiang Xue <qiang.xue@gmail.com>
+ * @version $Revision: $ $Date: $
+ * @package System.Collections
+ * @since 3.0
+ */
+class TQueue extends TComponent implements IteratorAggregate
+{
+ /**
+ * internal data storage
+ * @var array
+ */
+ private $_d=array();
+ /**
+ * number of items
+ * @var integer
+ */
+ private $_c=0;
+
+ /**
+ * Constructor.
+ * Initializes the queue with an array or an iterable object.
+ * @param array|Iterator the intial data. Default is null, meaning no initialization.
+ * @throws TInvalidDataTypeException If data is not null and neither an array nor an iterator.
+ */
+ public function __construct($data=null)
+ {
+ if($data!==null)
+ $this->copyFrom($data);
+ }
+
+ /**
+ * @return array the list of items in queue
+ */
+ public function toArray()
+ {
+ return $this->_d;
+ }
+
+ /**
+ * Copies iterable data into the queue.
+ * Note, existing data in the list will be cleared first.
+ * @param mixed the data to be copied from, must be an array or object implementing Traversable
+ * @throws TInvalidDataTypeException If data is neither an array nor a Traversable.
+ */
+ public function copyFrom($data)
+ {
+ if(is_array($data) || ($data instanceof Traversable))
+ {
+ $this->clear();
+ foreach($data as $item)
+ {
+ $this->_d[]=$item;
+ ++$this->_c;
+ }
+ }
+ else if($data!==null)
+ throw new TInvalidDataTypeException('queue_data_not_iterable');
+ }
+
+ /**
+ * Removes all items in the queue.
+ */
+ public function clear()
+ {
+ $this->_c=0;
+ $this->_d=array();
+ }
+
+ /**
+ * @param mixed the item
+ * @return boolean whether the queue contains the item
+ */
+ public function contains($item)
+ {
+ return array_search($item,$this->_d,true)!==false;
+ }
+
+ /**
+ * Returns the item at the top of the queue.
+ * Unlike {@link pop()}, this method does not remove the item from the queue.
+ * @return mixed item at the top of the queue
+ * @throws TInvalidOperationException if the queue is empty
+ */
+ public function peek()
+ {
+ if($this->_c===0)
+ throw new TInvalidOperationException('queue_empty');
+ else
+ return $this->_d[$this->_c-1];
+ }
+
+ /**
+ * Removes and returns the object at the beginning of the queue.
+ * @return mixed the item at the beginning of the queue
+ * @throws TInvalidOperationException if the queue is empty
+ */
+ public function dequeue()
+ {
+ if($this->_c===0)
+ throw new TInvalidOperationException('queue_empty');
+ else
+ {
+ --$this->_c;
+ return array_shift($this->_d);
+ }
+ }
+
+ /**
+ * Adds an object to the end of the queue.
+ * @param mixed the item to be appended into the queue
+ */
+ public function enqueue($item)
+ {
+ ++$this->_c;
+ array_push($this->_d,$item);
+ }
+
+ /**
+ * Returns an iterator for traversing the items in the queue.
+ * This method is required by the interface IteratorAggregate.
+ * @return Iterator an iterator for traversing the items in the queue.
+ */
+ public function getIterator()
+ {
+ return new TQueueIterator($this->_d);
+ }
+
+ /**
+ * @return integer the number of items in the queue
+ */
+ public function getCount()
+ {
+ return $this->_c;
+ }
+}
+
+/**
+ * TQueueIterator class
+ *
+ * TQueueIterator implements Iterator interface.
+ *
+ * TQueueIterator is used by TQueue. It allows TQueue to return a new iterator
+ * for traversing the items in the queue.
+ *
+ * @author Qiang Xue <qiang.xue@gmail.com>
+ * @version $Revision: $ $Date: $
+ * @package System.Collections
+ * @since 3.0
+ */
+class TQueueIterator implements Iterator
+{
+ /**
+ * @var array the data to be iterated through
+ */
+ private $_d;
+ /**
+ * @var integer index of the current item
+ */
+ private $_i;
+ /**
+ * @var integer count of the data items
+ */
+ private $_c;
+
+ /**
+ * Constructor.
+ * @param array the data to be iterated through
+ */
+ public function __construct(&$data)
+ {
+ $this->_d=&$data;
+ $this->_i=0;
+ $this->_c=count($this->_d);
+ }
+
+ /**
+ * Rewinds internal array pointer.
+ * This method is required by the interface Iterator.
+ */
+ public function rewind()
+ {
+ $this->_i=0;
+ }
+
+ /**
+ * Returns the key of the current array item.
+ * This method is required by the interface Iterator.
+ * @return integer the key of the current array item
+ */
+ public function key()
+ {
+ return $this->_i;
+ }
+
+ /**
+ * Returns the current array item.
+ * This method is required by the interface Iterator.
+ * @return mixed the current array item
+ */
+ public function current()
+ {
+ return $this->_d[$this->_i];
+ }
+
+ /**
+ * Moves the internal pointer to the next array item.
+ * This method is required by the interface Iterator.
+ */
+ public function next()
+ {
+ $this->_i++;
+ }
+
+ /**
+ * Returns whether there is an item at current position.
+ * This method is required by the interface Iterator.
+ * @return boolean
+ */
+ public function valid()
+ {
+ return $this->_i<$this->_c;
+ }
+}
+
+?>
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