ole.php

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<?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          |
// | [e-mail] so we can mail you a copy immediately.               |
// +----------------------------------------------------------------------+
// | Author: Xavier Noguer <[e-mail]>                              |
// | Based on OLE::Storage_Lite by Kawai, Takanori                        |
// +----------------------------------------------------------------------+
//
// $Id: OLE.php,v 1.15 2007/12/18 20:59:11 schmidt Exp $


/**
* Constants for OLE package
*/
define('OLE_PPS_TYPE_ROOT',        5);
define('OLE_PPS_TYPE_DIR',         1);
define('OLE_PPS_TYPE_FILE',        2);
define('OLE_DATA_SIZE_SMALL', 0x1000);
define('OLE_LONG_INT_SIZE',        4);
define('OLE_PPS_SIZE',          0x80);

require_once 'PEAR.php';

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

/**
* OLE package base class.
*
* @category Structures
* @package  OLE
* @author   Xavier Noguer <[e-mail]>
* @author   Christian Schmidt <[e-mail]>
*/
class OLE extends PEAR
{

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

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

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

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

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

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

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

    /**
    * Creates a new OLE object
    * @access public
    */
    function OLE()
    {
        $this->_list = array();
    }

    /**
    * Destructor (using PEAR)
    * Just closes the file handle on the OLE file.
    *
    * @access private
    */
    function _OLE()
    {
        fclose($this->_file_handle);
    }

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

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

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

        // Root chain 1st block
        $directoryFirstBlockId = $this->_readInt4($fh);

        // Skip unused bytes
        fseek($fh, 56);
        // Streams shorter than this are stored using small blocks
        $this->bigBlockThreshold = $this->_readInt4($fh);
        // Block id of first sector in Short Block Allocation Table
        $sbatFirstBlockId = $this->_readInt4($fh);
        // Number of blocks in Short Block Allocation Table
        $sbbatBlockCount = $this->_readInt4($fh);
        // Block id of first sector in Master Block Allocation Table
        $mbatFirstBlockId = $this->_readInt4($fh);
        // Number of blocks in Master Block Allocation Table
        $mbbatBlockCount = $this->_readInt4($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[] = $this->_readInt4($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[] = $this->_readInt4($fh);
            }
            // Last block id in each block points to next block
            $pos = $this->_getBlockOffset($this->_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[] = $this->_readInt4($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] = $this->_readInt4($sbatFh);
        }
        fclose($sbatFh);

        $this->_readPpsWks($directoryFirstBlockId);

        return true;
    }

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

    /**
     * Returns a stream for use with fread() etc. External callers should
     * use OLE_PPS_File::getStream().
     * @param int|PPS $blockIdOrPps block id or PPS
     * @return resource read-only stream
     */
    function getStream($blockIdOrPps)
    {
        include_once 'OLE/ChainedBlockStream.php';
        static $isRegistered = false;
        if (!$isRegistered) {
            stream_wrapper_register('ole-chainedblockstream',
                                    '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=' . $instanceId;
        if (is_a($blockIdOrPps, 'OLE_PPS')) {
            $path .= '&blockId=' . $blockIdOrPps->_StartBlock;
            $path .= '&size=' . $blockIdOrPps->Size;
        } else {
            $path .= '&blockId=' . $blockIdOrPps;
        }
        return fopen($path, 'r');
    }

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

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

    /**
     * Reads an unsigned long (4 octets).
     * @param   resource  file handle
     * @return  int
     * @access private
     */
    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