From c59b19644279bec4f388c9ebbee6936a00c20f99 Mon Sep 17 00:00:00 2001 From: xue <> Date: Wed, 15 Mar 2006 04:19:25 +0000 Subject: Added TStack. --- framework/Collections/TStack.php | 253 +++++++++++++++++++++++++++++++++++++++ 1 file changed, 253 insertions(+) create mode 100644 framework/Collections/TStack.php (limited to 'framework/Collections') diff --git a/framework/Collections/TStack.php b/framework/Collections/TStack.php new file mode 100644 index 00000000..de49031d --- /dev/null +++ b/framework/Collections/TStack.php @@ -0,0 +1,253 @@ + + * @link http://www.pradosoft.com/ + * @copyright Copyright © 2005 PradoSoft + * @license http://www.pradosoft.com/license/ + * @version $Revision: $ $Date: $ + * @package System.Collections + */ + +/** + * TStack class + * + * TStack implements a stack. + * + * The typical stack operations are implemented, which include + * {@link push()}, {@link pop()} and {@link peek()}. In addition, + * {@link contains()} can be used to check if an item is contained + * in the stack. To obtain the number of the items in the stack, + * check the {@link getCount Count} property. + * + * Items in the stack may be traversed using foreach as follows, + * + * foreach($stack as $item) ... + * + * + * @author Qiang Xue + * @version $Revision: $ $Date: $ + * @package System.Collections + * @since 3.0 + */ +class TStack extends TComponent implements IteratorAggregate +{ + /** + * internal data storage + * @var array + */ + private $_d=array(); + /** + * number of items + * @var integer + */ + private $_c=0; + + /** + * Constructor. + * Initializes the stack with an array or an iterable object. + * @param array|Iterator the intial data. Default is null, meaning no initialization. + * @throws TInvalidDataTypeException If data is not null and neither an array nor an iterator. + */ + public function __construct($data=null) + { + if($data!==null) + $this->copyFrom($data); + } + + /** + * @return array the list of items in stack + */ + public function toArray() + { + return $this->_d; + } + + /** + * Copies iterable data into the stack. + * Note, existing data in the list will be cleared first. + * @param mixed the data to be copied from, must be an array or object implementing Traversable + * @throws TInvalidDataTypeException If data is neither an array nor a Traversable. + */ + public function copyFrom($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('stack_data_not_iterable'); + } + + /** + * Removes all items in the stack. + */ + public function clear() + { + $this->_c=0; + $this->_d=array(); + } + + /** + * @param mixed the item + * @return boolean whether the stack contains the item + */ + public function contains($item) + { + return array_search($item,$this->_d,true))!==false; + } + + /** + * Returns the item at the top of the stack. + * Unlike {@link pop()}, this method does not remove the item from the stack. + * @return mixed item at the top of the stack + * @throws TInvalidOperationException if the stack is empty + */ + public function peek() + { + if($this->_c===0) + throw new TInvalidOperationException('stack_empty'); + else + return $this->_d[$this->_c-1]; + } + + /** + * Pops up the item at the top of the stack. + * @return mixed the item at the top of the stack + * @throws TInvalidOperationException if the stack is empty + */ + public function pop() + { + if($this->_c===0) + throw new TInvalidOperationException('stack_empty'); + else + { + --$this->_c; + return array_pop($this->_d); + } + } + + /** + * Pushes an item into the stack. + * @return mixed the item to be pushed into the stack + */ + public function push($item) + { + ++$this->_c; + array_push($this->_d,$item); + } + + /** + * Returns an iterator for traversing the items in the stack. + * This method is required by the interface IteratorAggregate. + * @return Iterator an iterator for traversing the items in the stack. + */ + public function getIterator() + { + return new TStackIterator($this->_d); + } + + /** + * @return integer the number of items in the stack + */ + public function getCount() + { + return $this->_c; + } +} + +/** + * TStackIterator class + * + * TStackIterator implements Iterator interface. + * + * TStackIterator is used by TStack. It allows TStack to return a new iterator + * for traversing the items in the list. + * + * @author Qiang Xue + * @version $Revision: $ $Date: $ + * @package System.Collections + * @since 3.0 + */ +class TStackIterator 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; + } +} + +?> \ No newline at end of file -- cgit v1.2.3