<?php

/**

 * PHPExcel

 *

 * Copyright (C) 2006 - 2014 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_Shared_OLE

 * @copyright  Copyright (c) 2006 - 2007 Christian Schmidt

 * @license    http://www.gnu.org/licenses/old-licenses/lgpl-2.1.txt	LGPL

 * @version 1.8.0, 2014-03-02

 */



/**

 * PHPExcel_Shared_OLE_ChainedBlockStream

 *

 * Stream wrapper for reading data stored in an OLE file. Implements methods

 * for PHP's stream_wrapper_register(). For creating streams using this

 * wrapper, use PHPExcel_Shared_OLE_PPS_File::getStream().

 *

 * @category   PHPExcel

 * @package    PHPExcel_Shared_OLE

 */

class PHPExcel_Shared_OLE_ChainedBlockStream

{

	/**

	 * The OLE container of the file that is being read.

	 * @var OLE

	 */

	public $ole;



	/**

	 * Parameters specified by fopen().

	 * @var array

	 */

	public $params;



	/**

	 * The binary data of the file.

	 * @var  string

	 */

	public $data;



	/**

	 * The file pointer.

	 * @var  int  byte offset

	 */

	public $pos;



	/**

	 * Implements support for fopen().

	 * For creating streams using this wrapper, use OLE_PPS_File::getStream().

	 *

	 * @param	string	$path			resource name including scheme, e.g.

	 *									ole-chainedblockstream://oleInstanceId=1

	 * @param	string	$mode			only "r" is supported

	 * @param	int		$options		mask of STREAM_REPORT_ERRORS and STREAM_USE_PATH

	 * @param	string  &$openedPath	absolute path of the opened stream (out parameter)

	 * @return	bool    true on success

	 */

	public function stream_open($path, $mode, $options, &$openedPath)

	{

		if ($mode != 'r') {

			if ($options & STREAM_REPORT_ERRORS) {

				trigger_error('Only reading is supported', E_USER_WARNING);

			}

			return false;

		}



		// 25 is length of "ole-chainedblockstream://"

		parse_str(substr($path, 25), $this->params);

		if (!isset($this->params['oleInstanceId'],

				   $this->params['blockId'],

				   $GLOBALS['_OLE_INSTANCES'][$this->params['oleInstanceId']])) {



			if ($options & STREAM_REPORT_ERRORS) {

				trigger_error('OLE stream not found', E_USER_WARNING);

			}

			return false;

		}

		$this->ole = $GLOBALS['_OLE_INSTANCES'][$this->params['oleInstanceId']];



		$blockId = $this->params['blockId'];

		$this->data = '';

		if (isset($this->params['size']) &&

			$this->params['size'] < $this->ole->bigBlockThreshold &&

			$blockId != $this->ole->root->_StartBlock) {



			// Block id refers to small blocks

			$rootPos = $this->ole->_getBlockOffset($this->ole->root->_StartBlock);

			while ($blockId != -2) {

				$pos = $rootPos + $blockId * $this->ole->bigBlockSize;

				$blockId = $this->ole->sbat[$blockId];

				fseek($this->ole->_file_handle, $pos);

				$this->data .= fread($this->ole->_file_handle, $this->ole->bigBlockSize);

			}

		} else {

			// Block id refers to big blocks

			while ($blockId != -2) {

				$pos = $this->ole->_getBlockOffset($blockId);

				fseek($this->ole->_file_handle, $pos);

				$this->data .= fread($this->ole->_file_handle, $this->ole->bigBlockSize);

				$blockId = $this->ole->bbat[$blockId];

			}

		}

		if (isset($this->params['size'])) {

			$this->data = substr($this->data, 0, $this->params['size']);

		}



		if ($options & STREAM_USE_PATH) {

			$openedPath = $path;

		}



		return true;

	}



	/**

	 * Implements support for fclose().

	 *

	 */

	public function stream_close()

	{

		$this->ole = null;

		unset($GLOBALS['_OLE_INSTANCES']);

	}



	/**

	 * Implements support for fread(), fgets() etc.

	 *

	 * @param   int		$count	maximum number of bytes to read

	 * @return  string

	 */

	public function stream_read($count)

	{

		if ($this->stream_eof()) {

			return false;

		}

		$s = substr($this->data, $this->pos, $count);

		$this->pos += $count;

		return $s;

	}



	/**

	 * Implements support for feof().

	 *

	 * @return  bool  TRUE if the file pointer is at EOF; otherwise FALSE

	 */

	public function stream_eof()

	{

//		As we don't support below 5.2 anymore, this is simply redundancy and overhead

//		$eof = $this->pos >= strlen($this->data);

//		// Workaround for bug in PHP 5.0.x: http://bugs.php.net/27508

//		if (version_compare(PHP_VERSION, '5.0', '>=') &&

//			version_compare(PHP_VERSION, '5.1', '<')) {

//		   $eof = !$eof;

//		}

//		return $eof;

		return $this->pos >= strlen($this->data);

	}



	/**

	 * Returns the position of the file pointer, i.e. its offset into the file

	 * stream. Implements support for ftell().

	 *

	 * @return  int

	 */

	public function stream_tell()

	{

		return $this->pos;

	}



	/**

	 * Implements support for fseek().

	 *

	 * @param	int		$offset	byte offset

	 * @param	int		$whence	SEEK_SET, SEEK_CUR or SEEK_END

	 * @return	bool

	 */

	public function stream_seek($offset, $whence)

	{

		if ($whence == SEEK_SET && $offset >= 0) {

			$this->pos = $offset;

		} elseif ($whence == SEEK_CUR && -$offset <= $this->pos) {

			$this->pos += $offset;

		} elseif ($whence == SEEK_END && -$offset <= sizeof($this->data)) {

			$this->pos = strlen($this->data) + $offset;

		} else {

			return false;

		}

		return true;

	}



	/**

	 * Implements support for fstat(). Currently the only supported field is

	 * "size".

	 * @return  array

	 */

	public function stream_stat()

	{

		return array(

			'size' => strlen($this->data),

			);

	}



	// Methods used by stream_wrapper_register() that are not implemented:

	// bool stream_flush ( void )

	// int stream_write ( string data )

	// bool rename ( string path_from, string path_to )

	// bool mkdir ( string path, int mode, int options )

	// bool rmdir ( string path, int options )

	// bool dir_opendir ( string path, int options )

	// array url_stat ( string path, int flags )

	// string dir_readdir ( void )

	// bool dir_rewinddir ( void )

	// bool dir_closedir ( void )

}

