<?php
/**
 * PHPExcel
 *
 * Copyright (c) 2006 - 2012 PHPExcel
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2.1 of the License, or (at your option) any later version.
 *
 * This library is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
 *
 * @category   PHPExcel
 * @package    PHPExcel_CachedObjectStorage
 * @copyright  Copyright (c) 2006 - 2012 PHPExcel (http://www.codeplex.com/PHPExcel)
 * @license    http://www.gnu.org/licenses/old-licenses/lgpl-2.1.txt	LGPL
 * @version    ##VERSION##, ##DATE##
 */


/**
 * PHPExcel_CachedObjectStorage_CacheBase
 *
 * @category   PHPExcel
 * @package    PHPExcel_CachedObjectStorage
 * @copyright  Copyright (c) 2006 - 2012 PHPExcel (http://www.codeplex.com/PHPExcel)
 */
abstract class PHPExcel_CachedObjectStorage_CacheBase {

	/**
	 * Parent worksheet
	 *
	 * @var PHPExcel_Worksheet
	 */
	protected $_parent;

	/**
	 * The currently active Cell
	 *
	 * @var PHPExcel_Cell
	 */
	protected $_currentObject = null;

	/**
	 * Coordinate address of the currently active Cell
	 *
	 * @var string
	 */
	protected $_currentObjectID = null;


	/**
	 * Flag indicating whether the currently active Cell requires saving
	 *
	 * @var boolean
	 */
	protected $_currentCellIsDirty = true;

	/**
	 * An array of cells or cell pointers for the worksheet cells held in this cache,
	 *		and indexed by their coordinate address within the worksheet
	 *
	 * @var array of mixed
	 */
	protected $_cellCache = array();


	/**
	 * Initialise this new cell collection
	 *
	 * @param	PHPExcel_Worksheet	$parent		The worksheet for this cell collection
	 */
	public function __construct(PHPExcel_Worksheet $parent) {
		//	Set our parent worksheet.
		//	This is maintained within the cache controller to facilitate re-attaching it to PHPExcel_Cell objects when
		//		they are woken from a serialized state
		$this->_parent = $parent;
	}	//	function __construct()


	/**
	 * Is a value set in the current PHPExcel_CachedObjectStorage_ICache for an indexed cell?
	 *
	 * @param	string		$pCoord		Coordinate address of the cell to check
	 * @return	boolean
	 */
	public function isDataSet($pCoord) {
		if ($pCoord === $this->_currentObjectID) {
			return true;
		}
		//	Check if the requested entry exists in the cache
		return isset($this->_cellCache[$pCoord]);
	}	//	function isDataSet()


    /**
     * Add or Update a cell in cache
     *
     * @param	PHPExcel_Cell	$cell		Cell to update
	 * @return	void
     * @throws	Exception
     */
	public function updateCacheData(PHPExcel_Cell $cell) {
		return $this->addCacheData($cell->getCoordinate(),$cell);
	}	//	function updateCacheData()


    /**
     * Delete a cell in cache identified by coordinate address
     *
     * @param	string			$pCoord		Coordinate address of the cell to delete
     * @throws	Exception
     */
	public function deleteCacheData($pCoord) {
		if ($pCoord === $this->_currentObjectID) {
			$this->_currentObject->detach();
			$this->_currentObjectID = $this->_currentObject = null;
		}

		if (is_object($this->_cellCache[$pCoord])) {
			$this->_cellCache[$pCoord]->detach();
			unset($this->_cellCache[$pCoord]);
		}
		$this->_currentCellIsDirty = false;
	}	//	function deleteCacheData()


	/**
	 * Get a list of all cell addresses currently held in cache
	 *
	 * @return	array of string
	 */
	public function getCellList() {
		return array_keys($this->_cellCache);
	}	//	function getCellList()


	/**
	 * Sort the list of all cell addresses currently held in cache by row and column
	 *
	 * @return	void
	 */
	public function getSortedCellList() {
		$sortKeys = array();
		foreach ($this->getCellList() as $coord) {
			list($column,$row) = sscanf($coord,'%[A-Z]%d');
			$sortKeys[sprintf('%09d%3s',$row,$column)] = $coord;
		}
		ksort($sortKeys);

		return array_values($sortKeys);
	}	//	function sortCellList()



	/**
	 * Get highest worksheet column and highest row that have cell records
	 *
	 * @return array Highest column name and highest row number
	 */
	public function getHighestRowAndColumn()
	{
		// Lookup highest column and highest row
		$col = array('A' => '1A');
		$row = array(1);
		foreach ($this->getCellList() as $coord) {
			list($c,$r) = sscanf($coord,'%[A-Z]%d');
			$row[$r] = $r;
			$col[$c] = strlen($c).$c;
		}
		if (!empty($row)) {
			// Determine highest column and row
			$highestRow = max($row);
			$highestColumn = substr(max($col),1);
		}

		return array( 'row'	   => $highestRow,
					  'column' => $highestColumn
					);
	}


	/**
	 * Get highest worksheet column
	 *
	 * @return string Highest column name
	 */
	public function getHighestColumn()
	{
		$colRow = $this->getHighestRowAndColumn();
		return $colRow['column'];
	}

	/**
	 * Get highest worksheet row
	 *
	 * @return int Highest row number
	 */
	public function getHighestRow()
	{
		$colRow = $this->getHighestRowAndColumn();
		return $colRow['row'];
	}


	/**
	 * Generate a unique ID for cache referencing
	 *
	 * @return string Unique Reference
	 */
	protected function _getUniqueID() {
		if (function_exists('posix_getpid')) {
			$baseUnique = posix_getpid();
		} else {
			$baseUnique = mt_rand();
		}
		return uniqid($baseUnique,true);
	}

	/**
	 * Clone the cell collection
	 *
	 * @param	PHPExcel_Worksheet	$parent		The new worksheet
	 * @return	void
	 */
	public function copyCellCollection(PHPExcel_Worksheet $parent) {
		$this->_parent = $parent;
		if (($this->_currentObject !== NULL) && (is_object($this->_currentObject))) {
			$this->_currentObject->attach($parent);
		}
	}	//	function copyCellCollection()


	/**
	 * Identify whether the caching method is currently available
	 * Some methods are dependent on the availability of certain extensions being enabled in the PHP build
	 *
	 * @return	boolean
	 */
	public static function cacheMethodIsAvailable() {
		return true;
	}

}