<?php
/* vim: set expandtab tabstop=4 shiftwidth=4: */
// +----------------------------------------------------------------------+
// | PHP Version 4                                                        |
// +----------------------------------------------------------------------+
// | Copyright (c) 1997-2002 The PHP Group                                |
// +----------------------------------------------------------------------+
// | This source file is subject to version 2.02 of the PHP license,      |
// | that is bundled with this package in the file LICENSE, and is        |
// | available at through the world-wide-web at                           |
// | http://www.php.net/license/2_02.txt.                                 |
// | If you did not receive a copy of the PHP license and are unable to   |
// | obtain it through the world-wide-web, please send a note to          |
// | license@php.net so we can mail you a copy immediately.               |
// +----------------------------------------------------------------------+
// | Author: Xavier Noguer <xnoguer@php.net>                              |
// | Based on OLE::Storage_Lite by Kawai, Takanori                        |
// +----------------------------------------------------------------------+
//
// $Id: OLE.php,v 1.13 2007/03/07 14:38:25 schmidt Exp $


/**
* Array for storing OLE instances that are accessed from
* OLE_ChainedBlockStream::stream_open().
* @var  array
*/
$GLOBALS['_OLE_INSTANCES'] = array();

/**
* OLE package base class.
*
* @author   Xavier Noguer <xnoguer@php.net>
* @author   Christian Schmidt <schmidt@php.net>
* @category   PHPExcel
* @package    PHPExcel_Shared_OLE
*/
class PHPExcel_Shared_OLE
{
	const OLE_PPS_TYPE_ROOT   =      5;
	const OLE_PPS_TYPE_DIR    =      1;
	const OLE_PPS_TYPE_FILE   =      2;
	const OLE_DATA_SIZE_SMALL = 0x1000;
	const OLE_LONG_INT_SIZE   =      4;
	const OLE_PPS_SIZE        =   0x80;

	/**
	 * The file handle for reading an OLE container
	 * @var resource
	*/
	public $_file_handle;

	/**
	* Array of PPS's found on the OLE container
	* @var array
	*/
	public $_list = array();

	/**
	 * Root directory of OLE container
	 * @var OLE_PPS_Root
	*/
	public $root;

	/**
	 * Big Block Allocation Table
	 * @var array  (blockId => nextBlockId)
	*/
	public $bbat;

	/**
	 * Short Block Allocation Table
	 * @var array  (blockId => nextBlockId)
	*/
	public $sbat;

	/**
	 * Size of big blocks. This is usually 512.
	 * @var  int  number of octets per block.
	*/
	public $bigBlockSize;

	/**
	 * Size of small blocks. This is usually 64.
	 * @var  int  number of octets per block
	*/
	public $smallBlockSize;

	/**
	 * Reads an OLE container from the contents of the file given.
	 *
	 * @acces public
	 * @param string $file
	 * @return mixed true on success, PEAR_Error on failure
	*/
	public function read($file)
	{
		$fh = fopen($file, "r");
		if (!$fh) {
			throw new Exception("Can't open file $file");
		}
		$this->_file_handle = $fh;

		$signature = fread($fh, 8);
		if ("\xD0\xCF\x11\xE0\xA1\xB1\x1A\xE1" != $signature) {
			throw new Exception("File doesn't seem to be an OLE container.");
		}
		fseek($fh, 28);
		if (fread($fh, 2) != "\xFE\xFF") {
			// This shouldn't be a problem in practice
			throw new Exception("Only Little-Endian encoding is supported.");
		}
		// Size of blocks and short blocks in bytes
		$this->bigBlockSize = pow(2, self::_readInt2($fh));
		$this->smallBlockSize  = pow(2, self::_readInt2($fh));

		// Skip UID, revision number and version number
		fseek($fh, 44);
		// Number of blocks in Big Block Allocation Table
		$bbatBlockCount = self::_readInt4($fh);

		// Root chain 1st block
		$directoryFirstBlockId = self::_readInt4($fh);

		// Skip unused bytes
		fseek($fh, 56);
		// Streams shorter than this are stored using small blocks
		$this->bigBlockThreshold = self::_readInt4($fh);
		// Block id of first sector in Short Block Allocation Table
		$sbatFirstBlockId = self::_readInt4($fh);
		// Number of blocks in Short Block Allocation Table
		$sbbatBlockCount = self::_readInt4($fh);
		// Block id of first sector in Master Block Allocation Table
		$mbatFirstBlockId = self::_readInt4($fh);
		// Number of blocks in Master Block Allocation Table
		$mbbatBlockCount = self::_readInt4($fh);
		$this->bbat = array();

		// Remaining 4 * 109 bytes of current block is beginning of Master
		// Block Allocation Table
		$mbatBlocks = array();
		for ($i = 0; $i < 109; ++$i) {
			$mbatBlocks[] = self::_readInt4($fh);
		}

		// Read rest of Master Block Allocation Table (if any is left)
		$pos = $this->_getBlockOffset($mbatFirstBlockId);
		for ($i = 0; $i < $mbbatBlockCount; ++$i) {
			fseek($fh, $pos);
			for ($j = 0; $j < $this->bigBlockSize / 4 - 1; ++$j) {
				$mbatBlocks[] = self::_readInt4($fh);
			}
			// Last block id in each block points to next block
			$pos = $this->_getBlockOffset(self::_readInt4($fh));
		}

		// Read Big Block Allocation Table according to chain specified by
		// $mbatBlocks
		for ($i = 0; $i < $bbatBlockCount; ++$i) {
			$pos = $this->_getBlockOffset($mbatBlocks[$i]);
			fseek($fh, $pos);
			for ($j = 0 ; $j < $this->bigBlockSize / 4; ++$j) {
				$this->bbat[] = self::_readInt4($fh);
			}
		}

		// Read short block allocation table (SBAT)
		$this->sbat = array();
		$shortBlockCount = $sbbatBlockCount * $this->bigBlockSize / 4;
		$sbatFh = $this->getStream($sbatFirstBlockId);
		for ($blockId = 0; $blockId < $shortBlockCount; ++$blockId) {
			$this->sbat[$blockId] = self::_readInt4($sbatFh);
		}
		fclose($sbatFh);

		$this->_readPpsWks($directoryFirstBlockId);

		return true;
	}

	/**
	 * @param  int  block id
	 * @param  int  byte offset from beginning of file
	 * @access public
	 */
	public function _getBlockOffset($blockId)
	{
		return 512 + $blockId * $this->bigBlockSize;
	}

	/**
	* Returns a stream for use with fread() etc. External callers should
	* use PHPExcel_Shared_OLE_PPS_File::getStream().
	* @param   int|PPS   block id or PPS
	* @return  resource  read-only stream
	*/
	public function getStream($blockIdOrPps)
	{
		static $isRegistered = false;
		if (!$isRegistered) {
			stream_wrapper_register('ole-chainedblockstream',
				'PHPExcel_Shared_OLE_ChainedBlockStream');
			$isRegistered = true;
		}

		// Store current instance in global array, so that it can be accessed
		// in OLE_ChainedBlockStream::stream_open().
		// Object is removed from self::$instances in OLE_Stream::close().
		$GLOBALS['_OLE_INSTANCES'][] = $this;
		$instanceId = end(array_keys($GLOBALS['_OLE_INSTANCES']));

		$path = 'ole-chainedblockstream://oleInstanceId=' . $instanceId;
		if ($blockIdOrPps instanceof PHPExcel_Shared_OLE_PPS) {
			$path .= '&blockId=' . $blockIdOrPps->_StartBlock;
			$path .= '&size=' . $blockIdOrPps->Size;
		} else {
			$path .= '&blockId=' . $blockIdOrPps;
		}
		return fopen($path, 'r');
	}

	/**
	 * Reads a signed char.
	 * @param   resource  file handle
	 * @return  int
	 * @access public
	 */
	private static function _readInt1($fh)
	{
		list(, $tmp) = unpack("c", fread($fh, 1));
		return $tmp;
	}

	/**
	 * Reads an unsigned short (2 octets).
	 * @param   resource  file handle
	 * @return  int
	 * @access public
	 */
	private static function _readInt2($fh)
	{
		list(, $tmp) = unpack("v", fread($fh, 2));
		return $tmp;
	}

	/**
	 * Reads an unsigned long (4 octets).
	 * @param   resource  file handle
	 * @return  int
	 * @access public
	 */
	private static function _readInt4($fh)
	{
		list(, $tmp) = unpack("V", fread($fh, 4));
		return $tmp;
	}

	/**
	* Gets information about all PPS's on the OLE container from the PPS WK's
	* creates an OLE_PPS object for each one.
	*
	* @access public
	* @param  integer  the block id of the first block
	* @return mixed true on success, PEAR_Error on failure
	*/
	public function _readPpsWks($blockId)
	{
		$fh = $this->getStream($blockId);
		for ($pos = 0; ; $pos += 128) {
			fseek($fh, $pos, SEEK_SET);
			$nameUtf16 = fread($fh, 64);
			$nameLength = self::_readInt2($fh);
			$nameUtf16 = substr($nameUtf16, 0, $nameLength - 2);
			// Simple conversion from UTF-16LE to ISO-8859-1
			$name = str_replace("\x00", "", $nameUtf16);
			$type = self::_readInt1($fh);
			switch ($type) {
			case self::OLE_PPS_TYPE_ROOT:
				$pps = new PHPExcel_Shared_OLE_PPS_Root(null, null, array());
				$this->root = $pps;
				break;
			case self::OLE_PPS_TYPE_DIR:
				$pps = new PHPExcel_Shared_OLE_PPS(null, null, null, null, null,
								   null, null, null, null, array());
				break;
			case self::OLE_PPS_TYPE_FILE:
				$pps = new PHPExcel_Shared_OLE_PPS_File($name);
				break;
			default:
				continue;
			}
			fseek($fh, 1, SEEK_CUR);
			$pps->Type    = $type;
			$pps->Name    = $name;
			$pps->PrevPps = self::_readInt4($fh);
			$pps->NextPps = self::_readInt4($fh);
			$pps->DirPps  = self::_readInt4($fh);
			fseek($fh, 20, SEEK_CUR);
			$pps->Time1st = self::OLE2LocalDate(fread($fh, 8));
			$pps->Time2nd = self::OLE2LocalDate(fread($fh, 8));
			$pps->_StartBlock = self::_readInt4($fh);
			$pps->Size = self::_readInt4($fh);
			$pps->No = count($this->_list);
			$this->_list[] = $pps;

			// check if the PPS tree (starting from root) is complete
			if (isset($this->root) &&
				$this->_ppsTreeComplete($this->root->No)) {

				break;
			}
		}
		fclose($fh);

		// Initialize $pps->children on directories
		foreach ($this->_list as $pps) {
			if ($pps->Type == self::OLE_PPS_TYPE_DIR || $pps->Type == self::OLE_PPS_TYPE_ROOT) {
				$nos = array($pps->DirPps);
				$pps->children = array();
				while ($nos) {
					$no = array_pop($nos);
					if ($no != -1) {
						$childPps = $this->_list[$no];
						$nos[] = $childPps->PrevPps;
						$nos[] = $childPps->NextPps;
						$pps->children[] = $childPps;
					}
				}
			}
		}

		return true;
	}

	/**
	* It checks whether the PPS tree is complete (all PPS's read)
	* starting with the given PPS (not necessarily root)
	*
	* @access public
	* @param integer $index The index of the PPS from which we are checking
	* @return boolean Whether the PPS tree for the given PPS is complete
	*/
	public function _ppsTreeComplete($index)
	{
		return isset($this->_list[$index]) &&
			   ($pps = $this->_list[$index]) &&
			   ($pps->PrevPps == -1 ||
				$this->_ppsTreeComplete($pps->PrevPps)) &&
			   ($pps->NextPps == -1 ||
				$this->_ppsTreeComplete($pps->NextPps)) &&
			   ($pps->DirPps == -1 ||
				$this->_ppsTreeComplete($pps->DirPps));
	}

	/**
	* Checks whether a PPS is a File PPS or not.
	* If there is no PPS for the index given, it will return false.
	*
	* @access public
	* @param integer $index The index for the PPS
	* @return bool true if it's a File PPS, false otherwise
	*/
	public function isFile($index)
	{
		if (isset($this->_list[$index])) {
			return ($this->_list[$index]->Type == self::OLE_PPS_TYPE_FILE);
		}
		return false;
	}

	/**
	* Checks whether a PPS is a Root PPS or not.
	* If there is no PPS for the index given, it will return false.
	*
	* @access public
	* @param integer $index The index for the PPS.
	* @return bool true if it's a Root PPS, false otherwise
	*/
	public function isRoot($index)
	{
		if (isset($this->_list[$index])) {
			return ($this->_list[$index]->Type == self::OLE_PPS_TYPE_ROOT);
		}
		return false;
	}

	/**
	* Gives the total number of PPS's found in the OLE container.
	*
	* @access public
	* @return integer The total number of PPS's found in the OLE container
	*/
	public function ppsTotal()
	{
		return count($this->_list);
	}

	/**
	* Gets data from a PPS
	* If there is no PPS for the index given, it will return an empty string.
	*
	* @access public
	* @param integer $index    The index for the PPS
	* @param integer $position The position from which to start reading
	*                          (relative to the PPS)
	* @param integer $length   The amount of bytes to read (at most)
	* @return string The binary string containing the data requested
	* @see OLE_PPS_File::getStream()
	*/
	public function getData($index, $position, $length)
	{
		// if position is not valid return empty string
		if (!isset($this->_list[$index]) || ($position >= $this->_list[$index]->Size) || ($position < 0)) {
			return '';
		}
		$fh = $this->getStream($this->_list[$index]);
		$data = stream_get_contents($fh, $length, $position);
		fclose($fh);
		return $data;
	}

	/**
	* Gets the data length from a PPS
	* If there is no PPS for the index given, it will return 0.
	*
	* @access public
	* @param integer $index    The index for the PPS
	* @return integer The amount of bytes in data the PPS has
	*/
	public function getDataLength($index)
	{
		if (isset($this->_list[$index])) {
			return $this->_list[$index]->Size;
		}
		return 0;
	}

	/**
	* Utility function to transform ASCII text to Unicode
	*
	* @access public
	* @static
	* @param string $ascii The ASCII string to transform
	* @return string The string in Unicode
	*/
	public static function Asc2Ucs($ascii)
	{
		$rawname = '';
		for ($i = 0; $i < strlen($ascii); ++$i) {
			$rawname .= $ascii{$i} . "\x00";
		}
		return $rawname;
	}

	/**
	* Utility function
	* Returns a string for the OLE container with the date given
	*
	* @access public
	* @static
	* @param integer $date A timestamp
	* @return string The string for the OLE container
	*/
	public static function LocalDate2OLE($date = null)
	{
		if (!isset($date)) {
			return "\x00\x00\x00\x00\x00\x00\x00\x00";
		}

		// factor used for separating numbers into 4 bytes parts
		$factor = pow(2, 32);

		// days from 1-1-1601 until the beggining of UNIX era
		$days = 134774;
		// calculate seconds
		$big_date = $days*24*3600 + gmmktime(date("H",$date),date("i",$date),date("s",$date),
											 date("m",$date),date("d",$date),date("Y",$date));
		// multiply just to make MS happy
		$big_date *= 10000000;

		$high_part = floor($big_date / $factor);
		// lower 4 bytes
		$low_part = floor((($big_date / $factor) - $high_part) * $factor);

		// Make HEX string
		$res = '';

		for ($i = 0; $i < 4; ++$i) {
			$hex = $low_part % 0x100;
			$res .= pack('c', $hex);
			$low_part /= 0x100;
		}
		for ($i = 0; $i < 4; ++$i) {
			$hex = $high_part % 0x100;
			$res .= pack('c', $hex);
			$high_part /= 0x100;
		}
		return $res;
	}

	/**
	* Returns a timestamp from an OLE container's date
	*
	* @access public
	* @static
	* @param integer $string A binary string with the encoded date
	* @return string The timestamp corresponding to the string
	*/
	public static function OLE2LocalDate($string)
	{
		if (strlen($string) != 8) {
			return new PEAR_Error("Expecting 8 byte string");
		}

		// factor used for separating numbers into 4 bytes parts
		$factor = pow(2,32);
		list(, $high_part) = unpack('V', substr($string, 4, 4));
		list(, $low_part) = unpack('V', substr($string, 0, 4));

		$big_date = ($high_part * $factor) + $low_part;
		// translate to seconds
		$big_date /= 10000000;

		// days from 1-1-1601 until the beggining of UNIX era
		$days = 134774;

		// translate to seconds from beggining of UNIX era
		$big_date -= $days * 24 * 3600;
		return floor($big_date);
	}
}
