File Source for BIFFwriter.php

<?php
/*
* Module written/ported by Xavier Noguer <xnoguer@php.net>
*
* 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:
*
* PHPExcel_Writer_Excel5_Writer: A library for generating Excel Spreadsheets
* Copyright (c) 2002-2003 Xavier Noguer xnoguer@php.net
*
* 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 <xnoguer@php.net>
* @category PHPExcel
* @package PHPExcel_Writer_Excel5
*/
class PHPExcel_Writer_Excel5_BIFFwriter
{
/**
* 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 PHPExcel_Writer_Excel5_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()
{
// 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.
throw new Exception("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);
}
/**
* General storage function like _append and _prepend, but returns string instead of modifying $this->_data
*
* @param string $data binary data to write
* @return string
*/
public function writeData($data)
{
if (strlen($data) > $this->_limit) {
$data = $this->_addContinue($data);
}
//$this->_data = $this->_data.$data;
$this->_datasize += strlen($data);
return $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
// According to the SDK $build and $year should be set to zero.
// However, this throws a warning in Excel 5. So, use magic numbers.
if ($this->_BIFF_version == 0x0500) {
$length = 0x0008;
$unknown = '';
$build = 0x096C;
$year = 0x07C9;
} elseif ($this->_BIFF_version == 0x0600) {
$length = 0x0010;
$unknown = pack("VV", 0x00000041, 0x00000006); //unknown last 8 bytes for BIFF8
$build = 0x0DBB;
$year = 0x07CC;
}
$version = $this->_BIFF_version;
$header = pack("vv", $record, $length);
$data = pack("vvvv", $version, $type, $build, $year);
$this->_prepend($header . $data . $unknown);
}
/**
* 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);
}
/**
* Writes Excel EOF record to indicate the end of a BIFF stream.
*
* @access private
*/
public function writeEof()
{
$record = 0x000A; // Record identifier
$length = 0x0000; // Number of bytes to follow
$header = pack("vv", $record, $length);
return $this->writeData($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.
$data_length = strlen($data);
for ($i = $limit; $i < ($data_length - $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;
}
}

Source for file BIFFwriter.php