<?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

 * @copyright  Copyright (c) 2006 - 2014 PHPExcel (http://www.codeplex.com/PHPExcel)

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

 * @version    1.8.0, 2014-03-02

 */



defined('IDENTIFIER_OLE') ||

    define('IDENTIFIER_OLE', pack('CCCCCCCC', 0xd0, 0xcf, 0x11, 0xe0, 0xa1, 0xb1, 0x1a, 0xe1));



class PHPExcel_Shared_OLERead {

	private $data = '';



	// OLE identifier

	const IDENTIFIER_OLE = IDENTIFIER_OLE;



	// Size of a sector = 512 bytes

	const BIG_BLOCK_SIZE					= 0x200;



	// Size of a short sector = 64 bytes

	const SMALL_BLOCK_SIZE					= 0x40;



	// Size of a directory entry always = 128 bytes

	const PROPERTY_STORAGE_BLOCK_SIZE		= 0x80;



	// Minimum size of a standard stream = 4096 bytes, streams smaller than this are stored as short streams

	const SMALL_BLOCK_THRESHOLD				= 0x1000;



	// header offsets

	const NUM_BIG_BLOCK_DEPOT_BLOCKS_POS	= 0x2c;

	const ROOT_START_BLOCK_POS				= 0x30;

	const SMALL_BLOCK_DEPOT_BLOCK_POS		= 0x3c;

	const EXTENSION_BLOCK_POS				= 0x44;

	const NUM_EXTENSION_BLOCK_POS			= 0x48;

	const BIG_BLOCK_DEPOT_BLOCKS_POS		= 0x4c;



	// property storage offsets (directory offsets)

	const SIZE_OF_NAME_POS					= 0x40;

	const TYPE_POS							= 0x42;

	const START_BLOCK_POS					= 0x74;

	const SIZE_POS							= 0x78;







	public $wrkbook						= null;

	public $summaryInformation			= null;

	public $documentSummaryInformation	= null;





	/**

	 * Read the file

	 *

	 * @param $sFileName string Filename

	 * @throws PHPExcel_Reader_Exception

	 */

	public function read($sFileName)

	{

		// Check if file exists and is readable

		if(!is_readable($sFileName)) {

			throw new PHPExcel_Reader_Exception("Could not open " . $sFileName . " for reading! File does not exist, or it is not readable.");

		}



		// Get the file identifier

		// Don't bother reading the whole file until we know it's a valid OLE file

		$this->data = file_get_contents($sFileName, FALSE, NULL, 0, 8);



		// Check OLE identifier

		if ($this->data != self::IDENTIFIER_OLE) {

			throw new PHPExcel_Reader_Exception('The filename ' . $sFileName . ' is not recognised as an OLE file');

		}



		// Get the file data

		$this->data = file_get_contents($sFileName);



		// Total number of sectors used for the SAT

		$this->numBigBlockDepotBlocks = self::_GetInt4d($this->data, self::NUM_BIG_BLOCK_DEPOT_BLOCKS_POS);



		// SecID of the first sector of the directory stream

		$this->rootStartBlock = self::_GetInt4d($this->data, self::ROOT_START_BLOCK_POS);



		// SecID of the first sector of the SSAT (or -2 if not extant)

		$this->sbdStartBlock = self::_GetInt4d($this->data, self::SMALL_BLOCK_DEPOT_BLOCK_POS);



		// SecID of the first sector of the MSAT (or -2 if no additional sectors are used)

		$this->extensionBlock = self::_GetInt4d($this->data, self::EXTENSION_BLOCK_POS);



		// Total number of sectors used by MSAT

		$this->numExtensionBlocks = self::_GetInt4d($this->data, self::NUM_EXTENSION_BLOCK_POS);



		$bigBlockDepotBlocks = array();

		$pos = self::BIG_BLOCK_DEPOT_BLOCKS_POS;



		$bbdBlocks = $this->numBigBlockDepotBlocks;



		if ($this->numExtensionBlocks != 0) {

			$bbdBlocks = (self::BIG_BLOCK_SIZE - self::BIG_BLOCK_DEPOT_BLOCKS_POS)/4;

		}



		for ($i = 0; $i < $bbdBlocks; ++$i) {

			  $bigBlockDepotBlocks[$i] = self::_GetInt4d($this->data, $pos);

			  $pos += 4;

		}



		for ($j = 0; $j < $this->numExtensionBlocks; ++$j) {

			$pos = ($this->extensionBlock + 1) * self::BIG_BLOCK_SIZE;

			$blocksToRead = min($this->numBigBlockDepotBlocks - $bbdBlocks, self::BIG_BLOCK_SIZE / 4 - 1);



			for ($i = $bbdBlocks; $i < $bbdBlocks + $blocksToRead; ++$i) {

				$bigBlockDepotBlocks[$i] = self::_GetInt4d($this->data, $pos);

				$pos += 4;

			}



			$bbdBlocks += $blocksToRead;

			if ($bbdBlocks < $this->numBigBlockDepotBlocks) {

				$this->extensionBlock = self::_GetInt4d($this->data, $pos);

			}

		}



		$pos = 0;

		$this->bigBlockChain = '';

		$bbs = self::BIG_BLOCK_SIZE / 4;

		for ($i = 0; $i < $this->numBigBlockDepotBlocks; ++$i) {

			$pos = ($bigBlockDepotBlocks[$i] + 1) * self::BIG_BLOCK_SIZE;



			$this->bigBlockChain .= substr($this->data, $pos, 4*$bbs);

			$pos += 4*$bbs;

		}



		$pos = 0;

		$sbdBlock = $this->sbdStartBlock;

		$this->smallBlockChain = '';

		while ($sbdBlock != -2) {

			$pos = ($sbdBlock + 1) * self::BIG_BLOCK_SIZE;



			$this->smallBlockChain .= substr($this->data, $pos, 4*$bbs);

			$pos += 4*$bbs;



			$sbdBlock = self::_GetInt4d($this->bigBlockChain, $sbdBlock*4);

		}



		// read the directory stream

		$block = $this->rootStartBlock;

		$this->entry = $this->_readData($block);



		$this->_readPropertySets();

	}



	/**

	 * Extract binary stream data

	 *

	 * @return string

	 */

	public function getStream($stream)

	{

		if ($stream === NULL) {

			return null;

		}



		$streamData = '';



		if ($this->props[$stream]['size'] < self::SMALL_BLOCK_THRESHOLD) {

			$rootdata = $this->_readData($this->props[$this->rootentry]['startBlock']);



			$block = $this->props[$stream]['startBlock'];



			while ($block != -2) {

	  			$pos = $block * self::SMALL_BLOCK_SIZE;

				$streamData .= substr($rootdata, $pos, self::SMALL_BLOCK_SIZE);



				$block = self::_GetInt4d($this->smallBlockChain, $block*4);

			}



			return $streamData;

		} else {

			$numBlocks = $this->props[$stream]['size'] / self::BIG_BLOCK_SIZE;

			if ($this->props[$stream]['size'] % self::BIG_BLOCK_SIZE != 0) {

				++$numBlocks;

			}



			if ($numBlocks == 0) return '';



			$block = $this->props[$stream]['startBlock'];



			while ($block != -2) {

				$pos = ($block + 1) * self::BIG_BLOCK_SIZE;

				$streamData .= substr($this->data, $pos, self::BIG_BLOCK_SIZE);

				$block = self::_GetInt4d($this->bigBlockChain, $block*4);

			}



			return $streamData;

		}

	}



	/**

	 * Read a standard stream (by joining sectors using information from SAT)

	 *

	 * @param int $bl Sector ID where the stream starts

	 * @return string Data for standard stream

	 */

	private function _readData($bl)

	{

		$block = $bl;

		$data = '';



		while ($block != -2)  {

			$pos = ($block + 1) * self::BIG_BLOCK_SIZE;

			$data .= substr($this->data, $pos, self::BIG_BLOCK_SIZE);

			$block = self::_GetInt4d($this->bigBlockChain, $block*4);

		}

		return $data;

	 }



	/**

	 * Read entries in the directory stream.

	 */

	private function _readPropertySets() {

		$offset = 0;



		// loop through entires, each entry is 128 bytes

		$entryLen = strlen($this->entry);

		while ($offset < $entryLen) {

			// entry data (128 bytes)

			$d = substr($this->entry, $offset, self::PROPERTY_STORAGE_BLOCK_SIZE);



			// size in bytes of name

			$nameSize = ord($d[self::SIZE_OF_NAME_POS]) | (ord($d[self::SIZE_OF_NAME_POS+1]) << 8);



			// type of entry

			$type = ord($d[self::TYPE_POS]);



			// sectorID of first sector or short sector, if this entry refers to a stream (the case with workbook)

			// sectorID of first sector of the short-stream container stream, if this entry is root entry

			$startBlock = self::_GetInt4d($d, self::START_BLOCK_POS);



			$size = self::_GetInt4d($d, self::SIZE_POS);



			$name = str_replace("\x00", "", substr($d,0,$nameSize));





			$this->props[] = array (

				'name' => $name,

				'type' => $type,

				'startBlock' => $startBlock,

				'size' => $size);



			// tmp helper to simplify checks

			$upName = strtoupper($name);



			// Workbook directory entry (BIFF5 uses Book, BIFF8 uses Workbook)

			if (($upName === 'WORKBOOK') || ($upName === 'BOOK')) {

				$this->wrkbook = count($this->props) - 1;

			}

			else if ( $upName === 'ROOT ENTRY' || $upName === 'R') {

				// Root entry

				$this->rootentry = count($this->props) - 1;

			}



			// Summary information

			if ($name == chr(5) . 'SummaryInformation') {

//				echo 'Summary Information<br />';

				$this->summaryInformation = count($this->props) - 1;

			}



			// Additional Document Summary information

			if ($name == chr(5) . 'DocumentSummaryInformation') {

//				echo 'Document Summary Information<br />';

				$this->documentSummaryInformation = count($this->props) - 1;

			}



			$offset += self::PROPERTY_STORAGE_BLOCK_SIZE;

		}



	}



	/**

	 * Read 4 bytes of data at specified position

	 *

	 * @param string $data

	 * @param int $pos

	 * @return int

	 */

	private static function _GetInt4d($data, $pos)

	{

		// FIX: represent numbers correctly on 64-bit system

		// http://sourceforge.net/tracker/index.php?func=detail&aid=1487372&group_id=99160&atid=623334

		// Hacked by Andreas Rehm 2006 to ensure correct result of the <<24 block on 32 and 64bit systems

		$_or_24 = ord($data[$pos + 3]);

		if ($_or_24 >= 128) {

			// negative number

			$_ord_24 = -abs((256 - $_or_24) << 24);

		} else {

			$_ord_24 = ($_or_24 & 127) << 24;

		}

		return ord($data[$pos]) | (ord($data[$pos + 1]) << 8) | (ord($data[$pos + 2]) << 16) | $_ord_24;

	}



}

