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<?php

/*

*  Module written/ported by Xavier Noguer <xnoguer@rezebra.com>

*

*  The majority of this is _NOT_ my code.  I simply ported it from the

*  PERL Spreadsheet::WriteExcel module.

*

*  The author of the Spreadsheet::WriteExcel module is John McNamara

*  <jmcnamara@cpan.org>

*

*  I _DO_ maintain this code, and John McNamara has nothing to do with the

*  porting of this code to PHP.  Any questions directly related to this

*  class library should be directed to me.

*

*  License Information:

*

*    Spreadsheet_Excel_Writer:  A library for generating Excel Spreadsheets

*    Copyright (c) 2002-2003 Xavier Noguer xnoguer@rezebra.com

*

*    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., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA

*/

require_once('PEAR.php');

/**

* Class for writing Excel BIFF records.

*

* From "MICROSOFT EXCEL BINARY FILE FORMAT" by Mark O'Brien (Microsoft Corporation):

*

* BIFF (BInary File Format) is the file format in which Excel documents are

* saved on disk.  A BIFF file is a complete description of an Excel document.

* BIFF files consist of sequences of variable-length records. There are many

* different types of BIFF records.  For example, one record type describes a

* formula entered into a cell; one describes the size and location of a

* window into a document; another describes a picture format.

*

* @author   Xavier Noguer <xnoguer@rezebra.com>

* @category FileFormats

* @package  Spreadsheet_Excel_Writer

*/

class Spreadsheet_Excel_Writer_BIFFwriter extends PEAR

{

    /**

    * The BIFF/Excel version (5).

    * @var integer

    */

    var $_BIFF_version = 0x0500;

    /**

    * The byte order of this architecture. 0 => little endian, 1 => big endian

    * @var integer

    */

    var $_byte_order;

    /**

    * The string containing the data of the BIFF stream

    * @var string

    */

    var $_data;

    /**

    * The size of the data in bytes. Should be the same as strlen($this->_data)

    * @var integer

    */

    var $_datasize;

    /**

    * The maximun length for a BIFF record. See _addContinue()

    * @var integer

    * @see _addContinue()

    */

    var $_limit;

    /**

    * Constructor

    *

    * @access public

    */

    function Spreadsheet_Excel_Writer_BIFFwriter()

    {

        $this->_byte_order = '';

        $this->_data       = '';

        $this->_datasize   = 0;

        $this->_limit      = 2080;

        // Set the byte order

        $this->_setByteOrder();

    }

/**

* Determine the byte order and store it as class data to avoid

* recalculating it for each call to new().

*

* @access private

*/

    function _setByteOrder()

    {

        if ($this->_byte_order == '')

        {

            // Check if "pack" gives the required IEEE 64bit float

            $teststr = pack("d", 1.2345);

            $number  = pack("C8", 0x8D, 0x97, 0x6E, 0x12, 0x83, 0xC0, 0xF3, 0x3F);

            if ($number == $teststr) {

                $byte_order = 0;    // Little Endian

            }

            elseif ($number == strrev($teststr)){

                $byte_order = 1;    // Big Endian

            }

            else {

                // Give up. I'll fix this in a later version.

                $this->raiseError("Required floating point format not supported ".

                    "on this platform.");

            }

        }

        $this->_byte_order = $byte_order;

    }

/**

* General storage function

*

* @param string $data binary data to prepend

* @access private

*/

    function _prepend($data)

    {

        if (strlen($data) > $this->_limit) {

            $data = $this->_addContinue($data);

        }

        $this->_data      = $data.$this->_data;

        $this->_datasize += strlen($data);

    }

/**

* General storage function

*

* @param string $data binary data to append

* @access private

*/

    function _append($data)

    {

        if (strlen($data) > $this->_limit) {

            $data = $this->_addContinue($data);

        }

        $this->_data      = $this->_data.$data;

        $this->_datasize += strlen($data);

    }

/**

* Writes Excel BOF record to indicate the beginning of a stream or

* sub-stream in the BIFF file.

*

* @param  integer $type type of BIFF file to write: 0x0005 Workbook, 0x0010 Worksheet.

* @access private

*/

    function _storeBof($type)

    {

        $record  = 0x0809;        // Record identifier

        $length  = 0x0008;        // Number of bytes to follow

        $version = $this->_BIFF_version;

        // According to the SDK $build and $year should be set to zero.

        // However, this throws a warning in Excel 5. So, use these

        // magic numbers.

        $build   = 0x096C;

        $year    = 0x07C9;

        $header  = pack("vv",   $record, $length);

        $data    = pack("vvvv", $version, $type, $build, $year);

        $this->_prepend($header.$data);

    }

/**

* Writes Excel EOF record to indicate the end of a BIFF stream.

*

* @access private

*/

    function _storeEof()

    {

        $record    = 0x000A;   // Record identifier

        $length    = 0x0000;   // Number of bytes to follow

        $header    = pack("vv", $record, $length);

        $this->_append($header);

    }

/**

* Excel limits the size of BIFF records. In Excel 5 the limit is 2084 bytes. In

* Excel 97 the limit is 8228 bytes. Records that are longer than these limits

* must be split up into CONTINUE blocks.

*

* This function takes a long BIFF record and inserts CONTINUE records as

* necessary.

*

* @param  string  $data The original binary data to be written

* @return string        A very convenient string of continue blocks

* @access private

*/

    function _addContinue($data)

    {

        $limit      = $this->_limit;

        $record     = 0x003C;         // Record identifier

        // The first 2080/8224 bytes remain intact. However, we have to change

        // the length field of the record.

        $tmp = substr($data, 0, 2).pack("v", $limit-4).substr($data, 4, $limit - 4);

        $header = pack("vv", $record, $limit);  // Headers for continue records

        // Retrieve chunks of 2080/8224 bytes +4 for the header.

        for($i = $limit; $i < strlen($data) - $limit; $i += $limit)

        {

            $tmp .= $header;

            $tmp .= substr($data, $i, $limit);

        }

        // Retrieve the last chunk of data

        $header  = pack("vv", $record, strlen($data) - $i);

        $tmp    .= $header;

        $tmp    .= substr($data,$i,strlen($data) - $i);

        return($tmp);

    }

}

?>