* * 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 * * * 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::WriteExcel: A library for generating Excel Spreadsheets * Copyright (C) 2002 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 */ /** * 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 * @package Spreadsheet_WriteExcel */ class BIFFWriter { var $_BIFF_version = 0x0500; /** * Constructor * * @access public */ function BIFFwriter() { // The byte order of this architecture. 0 => little endian, 1 => big endian $this->_byte_order = ''; // The string containing the data of the BIFF stream $this->_data = ''; // Should be the same as strlen($this->_data) $this->_datasize = 0; // The maximun length for a BIFF record. See _add_continue() $this->_limit = 2080; // Set the byte order $this->_set_byte_order(); } /** * Determine the byte order and store it as class data to avoid * recalculating it for each call to new(). * * @access private */ function _set_byte_order() { if ($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. die("Required floating point format not supported ". "on this platform. See the portability section ". "of the documentation." ); } } $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 = $this->_add_continue($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 = $this->_add_continue($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 $type type of BIFF file to write: 0x0005 Workbook, 0x0010 Worksheet. * @access private */ function _store_bof($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 _store_eof() { $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 $data The original binary data to be written * @return string A very convenient string of continue blocks * @access private */ function _add_continue($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); } } ?>