<?php
/**
 * A hash class which can use any PHP type as its key
 * and can be used like an array.
 *
 * Note: foreach($hash as $k => $v) will cause errors
 * if any key is not a string or an integer.
 *
 */
class Hash implements ArrayAccess, Iterator, Countable
{
	private $_keys = array();
	private $_values = array();
	
	private $_iteratorIndex = 0;

	public function __construct()
	{
	}

	public function count()
	{
		return count($this->_keys);
	}
	
	public function offsetExists($index)
	{
		$found = array_search($index, $this->_keys, true);
		return ($found === false) ? false : true;
	}

	public function offsetGet($index)
	{
		$valueIndex = array_search($index, $this->_keys, true);

		if($valueIndex === false)
			throw new Exception('Undefined offset "'.$index.'"');

		return $this->_values[$valueIndex];
	}

	public function offsetSet($index, $value)
	{
		$valueIndex = array_search($index, $this->_keys, true);
		if($valueIndex === false)
		{
			$valueIndex = count($this->_keys);
			$this->_keys[] = $index;
		}

		$this->_values[$valueIndex] = $value;
	}

	public function offsetUnset($index)
	{
		$valueIndex = array_search($index, $this->_keys, true);
		if($valueIndex === false)
			return;

		unset($this->_keys[$valueIndex]);
		unset($this->_values[$valueIndex]);
	}

	public function rewind()
	{
		$this->_iteratorIndex = 0;
	}

	public function current()
	{
		return $this->_values[$this->_iteratorIndex];		
	}

	public function key()
	{
		return $this->_keys[$this->_iteratorIndex];
	}

	public function next()
	{
		$this->_iteratorIndex++;
	}

	public function valid()
	{
		return !($this->_iteratorIndex >= count($this->_keys));
	}
	
}