source: sourcecode/application/libraries/PHPExcel/Shared/OLE/ChainedBlockStream.php @ 1

<?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 )
}