<?php 

class XLSXWriter
{
	//http://www.ecma-international.org/publications/standards/Ecma-376.htm
	//http://officeopenxml.com/SSstyles.php
	//------------------------------------------------------------------
	//http://office.microsoft.com/en-us/excel-help/excel-specifications-and-limits-HP010073849.aspx
	const EXCEL_2007_MAX_ROW=1048576;
	const EXCEL_2007_MAX_COL=16384;
	//------------------------------------------------------------------
	protected $title;
	protected $subject;
	protected $author;
	protected $company;
	protected $description;
	protected $keywords = array();
	
	protected $current_sheet;
	protected $sheets = array();
	protected $temp_files = array();
	protected $cell_styles = array();
	protected $number_formats = array();
	public function __construct()
	{
		if(!ini_get('date.timezone'))
		{
			//using date functions can kick out warning if this isn't set
			date_default_timezone_set('UTC');
		}
		$this->addCellStyle($number_format='GENERAL', $style_string=null);
		$this->addCellStyle($number_format='GENERAL', $style_string=null);
		$this->addCellStyle($number_format='GENERAL', $style_string=null);
		$this->addCellStyle($number_format='GENERAL', $style_string=null);
	}
	public function setTitle($title='') { $this->title=$title; }
	public function setSubject($subject='') { $this->subject=$subject; }
	public function setAuthor($author='') { $this->author=$author; }
	public function setCompany($company='') { $this->company=$company; }
	public function setKeywords($keywords='') { $this->keywords=$keywords; }
	public function setDescription($description='') { $this->description=$description; }
	public function setTempDir($tempdir='') { $this->tempdir=$tempdir; }
	public function __destruct()
	{ 
		if (!empty($this->temp_files)) {
			foreach($this->temp_files as $temp_file) {
				@unlink($temp_file);
			}
		}
	}
	protected function tempFilename()
	{
		$tempdir = !empty($this->tempdir) ? $this->tempdir : sys_get_temp_dir();
		$filename = tempnam($tempdir, "xlsx_writer_");
		$this->temp_files[] = $filename;
		return $filename;
	}
	public function writeToStdOut()
	{
		$temp_file = $this->tempFilename();
		self::writeToFile($temp_file);
		readfile($temp_file);
	}
	public function writeToString()
	{
		$temp_file = $this->tempFilename();
		self::writeToFile($temp_file);
		$string = file_get_contents($temp_file);
		return $string;
	}
	public function writeToFile($filename)
	{
		foreach($this->sheets as $sheet_name => $sheet) {
			self::finalizeSheet($sheet_name);//making sure all footers have been written
		}
		if ( file_exists( $filename ) ) {
			if ( is_writable( $filename ) ) {
				@unlink( $filename ); //if the zip already exists, remove it
			} else {
				self::log( "Error in " . __CLASS__ . "::" . __FUNCTION__ . ", file is not writeable." );
				return;
			}
		}
		$zip = new ZipArchive();
		if (empty($this->sheets))                       { self::log("Error in ".__CLASS__."::".__FUNCTION__.", no worksheets defined."); return; }
			if (!$zip->open($filename, ZipArchive::CREATE)) { self::log("Error in ".__CLASS__."::".__FUNCTION__.", unable to create zip."); return; }
				$zip->addEmptyDir("docProps/");
				$zip->addFromString("docProps/app.xml" , self::buildAppXML() );
				$zip->addFromString("docProps/core.xml", self::buildCoreXML());
				$zip->addEmptyDir("_rels/");
				$zip->addFromString("_rels/.rels", self::buildRelationshipsXML());
				$zip->addEmptyDir("xl/worksheets/");
				foreach($this->sheets as $sheet) {
					$zip->addFile($sheet->filename, "xl/worksheets/".$sheet->xmlname );
				}
				$zip->addFromString("xl/workbook.xml"         , self::buildWorkbookXML() );
		$zip->addFile($this->writeStylesXML(), "xl/styles.xml" );  //$zip->addFromString("xl/styles.xml"           , self::buildStylesXML() );
		$zip->addFromString("[Content_Types].xml"     , self::buildContentTypesXML() );
		$zip->addEmptyDir("xl/_rels/");
		$zip->addFromString("xl/_rels/workbook.xml.rels", self::buildWorkbookRelsXML() );
		$zip->close();
	}
	protected function initializeSheet($sheet_name, $col_widths=array(), $auto_filter=false, $freeze_rows=false, $freeze_columns=false )
	{
		//if already initialized
		if ($this->current_sheet==$sheet_name || isset($this->sheets[$sheet_name]))
			return;
		$sheet_filename = $this->tempFilename();
		$sheet_xmlname = 'sheet' . (count($this->sheets) + 1).".xml";
		$this->sheets[$sheet_name] = (object)array(
			'filename' => $sheet_filename,
			'sheetname' => $sheet_name,
			'xmlname' => $sheet_xmlname,
			'row_count' => 0,
			'file_writer' => new XLSXWriter_BuffererWriter($sheet_filename),
			'columns' => array(),
			'merge_cells' => array(),
			'max_cell_tag_start' => 0,
			'max_cell_tag_end' => 0,
			'auto_filter' => $auto_filter,
			'freeze_rows' => $freeze_rows,
			'freeze_columns' => $freeze_columns,
			'finalized' => false,
		);
		$sheet = &$this->sheets[$sheet_name];
		$tabselected = count($this->sheets) == 1 ? 'true' : 'false';//only first sheet is selected
		$max_cell=XLSXWriter::xlsCell(self::EXCEL_2007_MAX_ROW, self::EXCEL_2007_MAX_COL);//XFE1048577
		$sheet->file_writer->write('<?xml version="1.0" encoding="UTF-8" standalone="yes"?>' . "\n");
		$sheet->file_writer->write('<worksheet xmlns="http://schemas.openxmlformats.org/spreadsheetml/2006/main" xmlns:r="http://schemas.openxmlformats.org/officeDocument/2006/relationships">');
		$sheet->file_writer->write(  '<sheetPr filterMode="false">');
		$sheet->file_writer->write(    '<pageSetUpPr fitToPage="false"/>');
		$sheet->file_writer->write(  '</sheetPr>');
		$sheet->max_cell_tag_start = $sheet->file_writer->ftell();
		$sheet->file_writer->write('<dimension ref="A1:' . $max_cell . '"/>');
		$sheet->max_cell_tag_end = $sheet->file_writer->ftell();
		$sheet->file_writer->write(  '<sheetViews>');
		$sheet->file_writer->write(    '<sheetView colorId="64" defaultGridColor="true" rightToLeft="false" showFormulas="false" showGridLines="true" showOutlineSymbols="true" showRowColHeaders="true" showZeros="true" tabSelected="' . $tabselected . '" topLeftCell="A1" view="normal" windowProtection="false" workbookViewId="0" zoomScale="100" zoomScaleNormal="100" zoomScalePageLayoutView="100">');
		if ($sheet->freeze_rows && $sheet->freeze_columns) {
			$sheet->file_writer->write(      '<pane ySplit="'.$sheet->freeze_rows.'" xSplit="'.$sheet->freeze_columns.'" topLeftCell="'.self::xlsCell($sheet->freeze_rows, $sheet->freeze_columns).'" activePane="bottomRight" state="frozen"/>');
			$sheet->file_writer->write(      '<selection activeCell="'.self::xlsCell($sheet->freeze_rows, 0).'" activeCellId="0" pane="topRight" sqref="'.self::xlsCell($sheet->freeze_rows, 0).'"/>');
			$sheet->file_writer->write(      '<selection activeCell="'.self::xlsCell(0, $sheet->freeze_columns).'" activeCellId="0" pane="bottomLeft" sqref="'.self::xlsCell(0, $sheet->freeze_columns).'"/>');
			$sheet->file_writer->write(      '<selection activeCell="'.self::xlsCell($sheet->freeze_rows, $sheet->freeze_columns).'" activeCellId="0" pane="bottomRight" sqref="'.self::xlsCell($sheet->freeze_rows, $sheet->freeze_columns).'"/>');
		}
		elseif ($sheet->freeze_rows) {
			$sheet->file_writer->write(      '<pane ySplit="'.$sheet->freeze_rows.'" topLeftCell="'.self::xlsCell($sheet->freeze_rows, 0).'" activePane="bottomLeft" state="frozen"/>');
			$sheet->file_writer->write(      '<selection activeCell="'.self::xlsCell($sheet->freeze_rows, 0).'" activeCellId="0" pane="bottomLeft" sqref="'.self::xlsCell($sheet->freeze_rows, 0).'"/>');
		}
		elseif ($sheet->freeze_columns) {
			$sheet->file_writer->write(      '<pane xSplit="'.$sheet->freeze_columns.'" topLeftCell="'.self::xlsCell(0, $sheet->freeze_columns).'" activePane="topRight" state="frozen"/>');
			$sheet->file_writer->write(      '<selection activeCell="'.self::xlsCell(0, $sheet->freeze_columns).'" activeCellId="0" pane="topRight" sqref="'.self::xlsCell(0, $sheet->freeze_columns).'"/>');
		}
		else { // not frozen
			$sheet->file_writer->write(      '<selection activeCell="A1" activeCellId="0" pane="topLeft" sqref="A1"/>');
		}
		$sheet->file_writer->write(    '</sheetView>');
		$sheet->file_writer->write(  '</sheetViews>');
		$sheet->file_writer->write(  '<cols>');
		$i=0;
		if (!empty($col_widths)) {
			foreach($col_widths as $column_width) {
				$sheet->file_writer->write(  '<col collapsed="false" hidden="false" max="'.($i+1).'" min="'.($i+1).'" style="0" customWidth="true" width="'.floatval($column_width).'"/>');
				$i++;
			}
		}
		$sheet->file_writer->write(  '<col collapsed="false" hidden="false" max="1024" min="'.($i+1).'" style="0" customWidth="false" width="11.5"/>');
		$sheet->file_writer->write(  '</cols>');
		$sheet->file_writer->write(  '<sheetData>');
	}
	private function addCellStyle($number_format, $cell_style_string)
	{
		$number_format_idx = self::add_to_list_get_index($this->number_formats, $number_format);
		$lookup_string = $number_format_idx.";".$cell_style_string;
		$cell_style_idx = self::add_to_list_get_index($this->cell_styles, $lookup_string);
		return $cell_style_idx;
	}
	private function initializeColumnTypes($header_types)
	{
		$column_types = array();
		foreach($header_types as $v)
		{
			$number_format = self::numberFormatStandardized($v);
			$number_format_type = self::determineNumberFormatType($number_format);
			$cell_style_idx = $this->addCellStyle($number_format, $style_string=null);
			$column_types[] = array('number_format' => $number_format,//contains excel format like 'YYYY-MM-DD HH:MM:SS'
									'number_format_type' => $number_format_type, //contains friendly format like 'datetime'
									'default_cell_style' => $cell_style_idx,
								);
		}
		return $column_types;
	}
	public function writeSheetHeader($sheet_name, array $header_types, $col_options = null)
	{
		if (empty($sheet_name) || empty($header_types) || !empty($this->sheets[$sheet_name]))
			return;
		$suppress_row = isset($col_options['suppress_row']) ? intval($col_options['suppress_row']) : false;
		if (is_bool($col_options))
		{
			self::log( "Warning! passing $suppress_row=false|true to writeSheetHeader() is deprecated, this will be removed in a future version." );
			$suppress_row = intval($col_options);
		}
		$style = &$col_options;
		$col_widths = isset($col_options['widths']) ? (array)$col_options['widths'] : array();
		$auto_filter = isset($col_options['auto_filter']) ? intval($col_options['auto_filter']) : false;
		$freeze_rows = isset($col_options['freeze_rows']) ? intval($col_options['freeze_rows']) : false;
		$freeze_columns = isset($col_options['freeze_columns']) ? intval($col_options['freeze_columns']) : false;
		self::initializeSheet($sheet_name, $col_widths, $auto_filter, $freeze_rows, $freeze_columns);
		$sheet = &$this->sheets[$sheet_name];
		$sheet->columns = $this->initializeColumnTypes($header_types);
		if (!$suppress_row)
		{
			$header_row = array_keys($header_types);      
			$sheet->file_writer->write('<row collapsed="false" customFormat="false" customHeight="false" hidden="false" ht="12.1" outlineLevel="0" r="' . (1) . '">');
			foreach ($header_row as $c => $v) {
				$cell_style_idx = empty($style) ? $sheet->columns[$c]['default_cell_style'] : $this->addCellStyle( 'GENERAL', json_encode(isset($style[0]) ? $style[$c] : $style) );
				$this->writeCell($sheet->file_writer, 0, $c, $v, $number_format_type='n_string', $cell_style_idx);
			}
			$sheet->file_writer->write('</row>');
			$sheet->row_count++;
		}
		$this->current_sheet = $sheet_name;
	}
	public function writeSheetRow($sheet_name, array $row, $row_options=null)
	{
		if (empty($sheet_name))
			return;
		self::initializeSheet($sheet_name);
		$sheet = &$this->sheets[$sheet_name];
		if (count($sheet->columns) < count($row)) {
			$default_column_types = $this->initializeColumnTypes( array_fill($from=0, $until=count($row), 'GENERAL') );//will map to n_auto
			$sheet->columns = array_merge((array)$sheet->columns, $default_column_types);
		}
		
		if (!empty($row_options))
		{
			$ht = isset($row_options['height']) ? floatval($row_options['height']) : 12.1;
			$customHt = isset($row_options['height']) ? true : false;
			$hidden = isset($row_options['hidden']) ? (bool)($row_options['hidden']) : false;
			$collapsed = isset($row_options['collapsed']) ? (bool)($row_options['collapsed']) : false;
			$sheet->file_writer->write('<row collapsed="'.($collapsed).'" customFormat="false" customHeight="'.($customHt).'" hidden="'.($hidden).'" ht="'.($ht).'" outlineLevel="0" r="' . ($sheet->row_count + 1) . '">');
		}
		else
		{
			$sheet->file_writer->write('<row collapsed="false" customFormat="false" customHeight="false" hidden="false" ht="12.1" outlineLevel="0" r="' . ($sheet->row_count + 1) . '">');
		}
		$style = &$row_options;
		$c=0;
		foreach ($row as $v) {
			$number_format = $sheet->columns[$c]['number_format'];
			$number_format_type = $sheet->columns[$c]['number_format_type'];
			$cell_style_idx = empty($style) ? $sheet->columns[$c]['default_cell_style'] : $this->addCellStyle( $number_format, json_encode(isset($style[0]) ? $style[$c] : $style) );
			$this->writeCell($sheet->file_writer, $sheet->row_count, $c, $v, $number_format_type, $cell_style_idx);
			$c++;
		}
		$sheet->file_writer->write('</row>');
		$sheet->row_count++;
		$this->current_sheet = $sheet_name;
	}
	public function countSheetRows($sheet_name = '')
	{
		$sheet_name = $sheet_name ?: $this->current_sheet;
		return array_key_exists($sheet_name, $this->sheets) ? $this->sheets[$sheet_name]->row_count : 0;
	}
	protected function finalizeSheet($sheet_name)
	{
		if (empty($sheet_name) || $this->sheets[$sheet_name]->finalized)
			return;
		$sheet = &$this->sheets[$sheet_name];
		$sheet->file_writer->write(    '</sheetData>');
		if (!empty($sheet->merge_cells)) {
			$sheet->file_writer->write(    '<mergeCells>');
			foreach ($sheet->merge_cells as $range) {
				$sheet->file_writer->write(        '<mergeCell ref="' . $range . '"/>');
			}
			$sheet->file_writer->write(    '</mergeCells>');
		}
		$max_cell = self::xlsCell($sheet->row_count - 1, count($sheet->columns) - 1);
		if ($sheet->auto_filter) {
			$sheet->file_writer->write(    '<autoFilter ref="A1:' . $max_cell . '"/>');         
		}
		$sheet->file_writer->write(    '<printOptions headings="false" gridLines="false" gridLinesSet="true" horizontalCentered="false" verticalCentered="false"/>');
		$sheet->file_writer->write(    '<pageMargins left="0.5" right="0.5" top="1.0" bottom="1.0" header="0.5" footer="0.5"/>');
		$sheet->file_writer->write(    '<pageSetup blackAndWhite="false" cellComments="none" copies="1" draft="false" firstPageNumber="1" fitToHeight="1" fitToWidth="1" horizontalDpi="300" orientation="portrait" pageOrder="downThenOver" paperSize="1" scale="100" useFirstPageNumber="true" usePrinterDefaults="false" verticalDpi="300"/>');
		$sheet->file_writer->write(    '<headerFooter differentFirst="false" differentOddEven="false">');
		$sheet->file_writer->write(        '<oddHeader>&amp;C&amp;&quot;Times New Roman,Regular&quot;&amp;12&amp;A</oddHeader>');
		$sheet->file_writer->write(        '<oddFooter>&amp;C&amp;&quot;Times New Roman,Regular&quot;&amp;12Page &amp;P</oddFooter>');
		$sheet->file_writer->write(    '</headerFooter>');
		$sheet->file_writer->write('</worksheet>');
		$max_cell_tag = '<dimension ref="A1:' . $max_cell . '"/>';
		$padding_length = $sheet->max_cell_tag_end - $sheet->max_cell_tag_start - strlen($max_cell_tag);
		$sheet->file_writer->fseek($sheet->max_cell_tag_start);
		$sheet->file_writer->write($max_cell_tag.str_repeat(" ", $padding_length));
		$sheet->file_writer->close();
		$sheet->finalized=true;
	}
	public function markMergedCell($sheet_name, $start_cell_row, $start_cell_column, $end_cell_row, $end_cell_column)
	{
		if (empty($sheet_name) || $this->sheets[$sheet_name]->finalized)
			return;
		self::initializeSheet($sheet_name);
		$sheet = &$this->sheets[$sheet_name];
		$startCell = self::xlsCell($start_cell_row, $start_cell_column);
		$endCell = self::xlsCell($end_cell_row, $end_cell_column);
		$sheet->merge_cells[] = $startCell . ":" . $endCell;
	}
	public function writeSheet(array $data, $sheet_name='', array $header_types=array(), $style=array())
	{
		$sheet_name = empty($sheet_name) ? 'Sheet1' : $sheet_name;
		$data = empty($data) ? array(array('')) : $data;
		if (!empty($header_types))
			isset($style['header']) ? $this->writeSheetHeader($sheet_name, $header_types, $style['header']) : $this->writeSheetHeader($sheet_name, $header_types);
		
		foreach($data as $i=>$row)
			isset($style['content']) ? $this->writeSheetRow($sheet_name, $row, $style['content']) : $this->writeSheetRow($sheet_name, $row);

		$this->finalizeSheet($sheet_name);
	}
	protected function writeCell(XLSXWriter_BuffererWriter &$file, $row_number, $column_number, $value, $num_format_type, $cell_style_idx)
	{
		$cell_name = self::xlsCell($row_number, $column_number);
		if (!is_scalar($value) || $value==='') { //objects, array, empty
			$file->write('<c r="'.$cell_name.'" s="'.$cell_style_idx.'"/>');
		} elseif (is_string($value) && $value{0}=='='){
			$file->write('<c r="'.$cell_name.'" s="'.$cell_style_idx.'" t="s"><f>'.self::xmlspecialchars($value).'</f></c>');
		} elseif ($num_format_type=='n_date') {
			$file->write('<c r="'.$cell_name.'" s="'.$cell_style_idx.'" t="n"><v>'.intval(self::convert_date_time($value)).'</v></c>');
		} elseif ($num_format_type=='n_datetime') {
			$file->write('<c r="'.$cell_name.'" s="'.$cell_style_idx.'" t="n"><v>'.self::convert_date_time($value).'</v></c>');
		} elseif ($num_format_type=='n_numeric') {
			$file->write('<c r="'.$cell_name.'" s="'.$cell_style_idx.'" t="n"><v>'.self::xmlspecialchars($value).'</v></c>');//int,float,currency
		} elseif ($num_format_type=='n_string') {
			$file->write('<c r="'.$cell_name.'" s="'.$cell_style_idx.'" t="inlineStr"><is><t>'.self::xmlspecialchars($value).'</t></is></c>');
		} elseif ($num_format_type=='n_auto' || 1) { //auto-detect unknown column types
			if (!is_string($value) || $value=='0' || ($value[0]!='0' && ctype_digit($value)) || preg_match("/^\-?(0|[1-9][0-9]*)(\.[0-9]+)?$/", $value)){
				$file->write('<c r="'.$cell_name.'" s="'.$cell_style_idx.'" t="n"><v>'.self::xmlspecialchars($value).'</v></c>');//int,float,currency
			} else { //implied: ($cell_format=='string')
			$file->write('<c r="'.$cell_name.'" s="'.$cell_style_idx.'" t="inlineStr"><is><t>'.self::xmlspecialchars($value).'</t></is></c>');
		}
	}
}
protected function styleFontIndexes()
{
	static $border_allowed = array('left','right','top','bottom');
	static $border_style_allowed = array('thin','medium','thick','dashDot','dashDotDot','dashed','dotted','double','hair','mediumDashDot','mediumDashDotDot','mediumDashed','slantDashDot');
	static $horizontal_allowed = array('general','left','right','justify','center');
	static $vertical_allowed = array('bottom','center','distributed','top');
	$default_font = array('size'=>'10','name'=>'Arial','family'=>'2');
		$fills = array('','');//2 placeholders for static xml later
		$fonts = array('','','','');//4 placeholders for static xml later
		$borders = array('');//1 placeholder for static xml later
		$style_indexes = array();
		foreach($this->cell_styles as $i=>$cell_style_string)
		{
			$semi_colon_pos = strpos($cell_style_string,";");
			$number_format_idx = substr($cell_style_string, 0, $semi_colon_pos);
			$style_json_string = substr($cell_style_string, $semi_colon_pos+1);
			$style = @json_decode($style_json_string, $as_assoc=true);
			$style_indexes[$i] = array('num_fmt_idx'=>$number_format_idx);//initialize entry
			if (isset($style['border']) && is_string($style['border']))//border is a comma delimited str
			{
				$border_value['side'] = array_intersect(explode(",", $style['border']), $border_allowed);
				if (isset($style['border-style']) && in_array($style['border-style'],$border_style_allowed))
				{
					$border_value['style'] = $style['border-style'];
				}
				if (isset($style['border-color']) && is_string($style['border-color']) && $style['border-color'][0]=='#')
				{
					$v = substr($style['border-color'],1,6);
					$v = strlen($v)==3 ? $v[0].$v[0].$v[1].$v[1].$v[2].$v[2] : $v;// expand cf0 => ccff00
					$border_value['color'] = "FF".strtoupper($v);
				}
				$style_indexes[$i]['border_idx'] = self::add_to_list_get_index($borders, json_encode($border_value));
			}
			if (isset($style['fill']) && is_string($style['fill']) && $style['fill'][0]=='#')
			{
				$v = substr($style['fill'],1,6);
				$v = strlen($v)==3 ? $v[0].$v[0].$v[1].$v[1].$v[2].$v[2] : $v;// expand cf0 => ccff00
				$style_indexes[$i]['fill_idx'] = self::add_to_list_get_index($fills, "FF".strtoupper($v) );
			}
			if (isset($style['halign']) && in_array($style['halign'],$horizontal_allowed))
			{
				$style_indexes[$i]['alignment'] = true;
				$style_indexes[$i]['halign'] = $style['halign'];
			}
			if (isset($style['valign']) && in_array($style['valign'],$vertical_allowed))
			{
				$style_indexes[$i]['alignment'] = true;
				$style_indexes[$i]['valign'] = $style['valign'];
			}
			if (isset($style['wrap_text']))
			{
				$style_indexes[$i]['alignment'] = true;
				$style_indexes[$i]['wrap_text'] = (bool)$style['wrap_text'];
			}
			$font = $default_font;
			if (isset($style['font-size']))
			{
				$font['size'] = floatval($style['font-size']);//floatval to allow "10.5" etc
			}
			if (isset($style['font']) && is_string($style['font']))
			{
				if ($style['font']=='Comic Sans MS') { $font['family']=4; }
				if ($style['font']=='Times New Roman') { $font['family']=1; }
				if ($style['font']=='Courier New') { $font['family']=3; }
				$font['name'] = strval($style['font']);
			}
			if (isset($style['font-style']) && is_string($style['font-style']))
			{
				if (strpos($style['font-style'], 'bold')!==false) { $font['bold'] = true; }
				if (strpos($style['font-style'], 'italic')!==false) { $font['italic'] = true; }
				if (strpos($style['font-style'], 'strike')!==false) { $font['strike'] = true; }
				if (strpos($style['font-style'], 'underline')!==false) { $font['underline'] = true; }
			}
			if (isset($style['color']) && is_string($style['color']) && $style['color'][0]=='#' )
			{
				$v = substr($style['color'],1,6);
				$v = strlen($v)==3 ? $v[0].$v[0].$v[1].$v[1].$v[2].$v[2] : $v;// expand cf0 => ccff00
				$font['color'] = "FF".strtoupper($v);
			}
			if ($font!=$default_font)
			{
				$style_indexes[$i]['font_idx'] = self::add_to_list_get_index($fonts, json_encode($font) );
			}
		}
		return array('fills'=>$fills,'fonts'=>$fonts,'borders'=>$borders,'styles'=>$style_indexes );
	}
	protected function writeStylesXML()
	{
		$r = self::styleFontIndexes();
		$fills = $r['fills'];
		$fonts = $r['fonts'];
		$borders = $r['borders'];
		$style_indexes = $r['styles'];
		$temporary_filename = $this->tempFilename();
		$file = new XLSXWriter_BuffererWriter($temporary_filename);
		$file->write('<?xml version="1.0" encoding="UTF-8" standalone="yes"?>'."\n");
		$file->write('<styleSheet xmlns="http://schemas.openxmlformats.org/spreadsheetml/2006/main">');
		$file->write('<numFmts count="'.count($this->number_formats).'">');
		foreach($this->number_formats as $i=>$v) {
			$file->write('<numFmt numFmtId="'.(164+$i).'" formatCode="'.self::xmlspecialchars($v).'" />');
		}
		//$file->write(     '<numFmt formatCode="GENERAL" numFmtId="164"/>');
		//$file->write(     '<numFmt formatCode="[$$-1009]#,##0.00;[RED]\-[$$-1009]#,##0.00" numFmtId="165"/>');
		//$file->write(     '<numFmt formatCode="YYYY-MM-DD\ HH:MM:SS" numFmtId="166"/>');
		//$file->write(     '<numFmt formatCode="YYYY-MM-DD" numFmtId="167"/>');
		$file->write('</numFmts>');
		$file->write('<fonts count="'.(count($fonts)).'">');
		$file->write(       '<font><name val="Arial"/><charset val="1"/><family val="2"/><sz val="10"/></font>');
		$file->write(       '<font><name val="Arial"/><family val="0"/><sz val="10"/></font>');
		$file->write(       '<font><name val="Arial"/><family val="0"/><sz val="10"/></font>');
		$file->write(       '<font><name val="Arial"/><family val="0"/><sz val="10"/></font>');
		foreach($fonts as $font) {
			if (!empty($font)) { //fonts have 4 empty placeholders in array to offset the 4 static xml entries above
				$f = json_decode($font,true);
				$file->write('<font>');
				$file->write(   '<name val="'.htmlspecialchars($f['name']).'"/><charset val="1"/><family val="'.intval($f['family']).'"/>');
				$file->write(   '<sz val="'.intval($f['size']).'"/>');
				if (!empty($f['color'])) { $file->write('<color rgb="'.strval($f['color']).'"/>'); }
				if (!empty($f['bold'])) { $file->write('<b val="true"/>'); }
				if (!empty($f['italic'])) { $file->write('<i val="true"/>'); }
				if (!empty($f['underline'])) { $file->write('<u val="single"/>'); }
				if (!empty($f['strike'])) { $file->write('<strike val="true"/>'); }
				$file->write('</font>');
			}
		}
		$file->write('</fonts>');
		$file->write('<fills count="'.(count($fills)).'">');
		$file->write(   '<fill><patternFill patternType="none"/></fill>');
		$file->write(   '<fill><patternFill patternType="gray125"/></fill>');
		foreach($fills as $fill) {
			if (!empty($fill)) { //fills have 2 empty placeholders in array to offset the 2 static xml entries above
				$file->write('<fill><patternFill patternType="solid"><fgColor rgb="'.strval($fill).'"/><bgColor indexed="64"/></patternFill></fill>');
			}
		}
		$file->write('</fills>');
		$file->write('<borders count="'.(count($borders)).'">');
		$file->write(    '<border diagonalDown="false" diagonalUp="false"><left/><right/><top/><bottom/><diagonal/></border>');
		foreach($borders as $border) {
			if (!empty($border)) { //fonts have an empty placeholder in the array to offset the static xml entry above
				$pieces = json_decode($border,true);
				$border_style = !empty($pieces['style']) ? $pieces['style'] : 'hair';
				$border_color = !empty($pieces['color']) ? '<color rgb="'.strval($pieces['color']).'"/>' : '';
				$file->write('<border diagonalDown="false" diagonalUp="false">');
				foreach (array('left', 'right', 'top', 'bottom') as $side)
				{
					$show_side = in_array($side,$pieces['side']) ? true : false;
					$file->write($show_side ? "<$side style=\"$border_style\">$border_color</$side>" : "<$side/>");
				}
				$file->write(  '<diagonal/>');
				$file->write('</border>');
			}
		}
		$file->write('</borders>');
		$file->write('<cellStyleXfs count="20">');
		$file->write(       '<xf applyAlignment="true" applyBorder="true" applyFont="true" applyProtection="true" borderId="0" fillId="0" fontId="0" numFmtId="164">');
		$file->write(       '<alignment horizontal="general" indent="0" shrinkToFit="false" textRotation="0" vertical="bottom" wrapText="false"/>');
		$file->write(       '<protection hidden="false" locked="true"/>');
		$file->write(       '</xf>');
		$file->write(       '<xf applyAlignment="false" applyBorder="false" applyFont="true" applyProtection="false" borderId="0" fillId="0" fontId="1" numFmtId="0"/>');
		$file->write(       '<xf applyAlignment="false" applyBorder="false" applyFont="true" applyProtection="false" borderId="0" fillId="0" fontId="1" numFmtId="0"/>');
		$file->write(       '<xf applyAlignment="false" applyBorder="false" applyFont="true" applyProtection="false" borderId="0" fillId="0" fontId="2" numFmtId="0"/>');
		$file->write(       '<xf applyAlignment="false" applyBorder="false" applyFont="true" applyProtection="false" borderId="0" fillId="0" fontId="2" numFmtId="0"/>');
		$file->write(       '<xf applyAlignment="false" applyBorder="false" applyFont="true" applyProtection="false" borderId="0" fillId="0" fontId="0" numFmtId="0"/>');
		$file->write(       '<xf applyAlignment="false" applyBorder="false" applyFont="true" applyProtection="false" borderId="0" fillId="0" fontId="0" numFmtId="0"/>');
		$file->write(       '<xf applyAlignment="false" applyBorder="false" applyFont="true" applyProtection="false" borderId="0" fillId="0" fontId="0" numFmtId="0"/>');
		$file->write(       '<xf applyAlignment="false" applyBorder="false" applyFont="true" applyProtection="false" borderId="0" fillId="0" fontId="0" numFmtId="0"/>');
		$file->write(       '<xf applyAlignment="false" applyBorder="false" applyFont="true" applyProtection="false" borderId="0" fillId="0" fontId="0" numFmtId="0"/>');
		$file->write(       '<xf applyAlignment="false" applyBorder="false" applyFont="true" applyProtection="false" borderId="0" fillId="0" fontId="0" numFmtId="0"/>');
		$file->write(       '<xf applyAlignment="false" applyBorder="false" applyFont="true" applyProtection="false" borderId="0" fillId="0" fontId="0" numFmtId="0"/>');
		$file->write(       '<xf applyAlignment="false" applyBorder="false" applyFont="true" applyProtection="false" borderId="0" fillId="0" fontId="0" numFmtId="0"/>');
		$file->write(       '<xf applyAlignment="false" applyBorder="false" applyFont="true" applyProtection="false" borderId="0" fillId="0" fontId="0" numFmtId="0"/>');
		$file->write(       '<xf applyAlignment="false" applyBorder="false" applyFont="true" applyProtection="false" borderId="0" fillId="0" fontId="0" numFmtId="0"/>');
		$file->write(       '<xf applyAlignment="false" applyBorder="false" applyFont="true" applyProtection="false" borderId="0" fillId="0" fontId="1" numFmtId="43"/>');
		$file->write(       '<xf applyAlignment="false" applyBorder="false" applyFont="true" applyProtection="false" borderId="0" fillId="0" fontId="1" numFmtId="41"/>');
		$file->write(       '<xf applyAlignment="false" applyBorder="false" applyFont="true" applyProtection="false" borderId="0" fillId="0" fontId="1" numFmtId="44"/>');
		$file->write(       '<xf applyAlignment="false" applyBorder="false" applyFont="true" applyProtection="false" borderId="0" fillId="0" fontId="1" numFmtId="42"/>');
		$file->write(       '<xf applyAlignment="false" applyBorder="false" applyFont="true" applyProtection="false" borderId="0" fillId="0" fontId="1" numFmtId="9"/>');
		$file->write('</cellStyleXfs>');
		$file->write('<cellXfs count="'.(count($style_indexes)).'">');
		//$file->write(     '<xf applyAlignment="false" applyBorder="false" applyFont="false" applyProtection="false" borderId="0" fillId="0" fontId="0" numFmtId="164" xfId="0"/>');
		//$file->write(     '<xf applyAlignment="false" applyBorder="false" applyFont="false" applyProtection="false" borderId="0" fillId="0" fontId="0" numFmtId="165" xfId="0"/>');
		//$file->write(     '<xf applyAlignment="false" applyBorder="false" applyFont="false" applyProtection="false" borderId="0" fillId="0" fontId="0" numFmtId="166" xfId="0"/>');
		//$file->write(     '<xf applyAlignment="false" applyBorder="false" applyFont="false" applyProtection="false" borderId="0" fillId="0" fontId="0" numFmtId="167" xfId="0"/>');
		foreach($style_indexes as $v)
		{
			$applyAlignment = isset($v['alignment']) ? 'true' : 'false';
			$wrapText = !empty($v['wrap_text']) ? 'true' : 'false';
			$horizAlignment = isset($v['halign']) ? $v['halign'] : 'general';
			$vertAlignment = isset($v['valign']) ? $v['valign'] : 'bottom';
			$applyBorder = isset($v['border_idx']) ? 'true' : 'false';
			$applyFont = 'true';
			$borderIdx = isset($v['border_idx']) ? intval($v['border_idx']) : 0;
			$fillIdx = isset($v['fill_idx']) ? intval($v['fill_idx']) : 0;
			$fontIdx = isset($v['font_idx']) ? intval($v['font_idx']) : 0;
			//$file->write('<xf applyAlignment="'.$applyAlignment.'" applyBorder="'.$applyBorder.'" applyFont="'.$applyFont.'" applyProtection="false" borderId="'.($borderIdx).'" fillId="'.($fillIdx).'" fontId="'.($fontIdx).'" numFmtId="'.(164+$v['num_fmt_idx']).'" xfId="0"/>');
			$file->write('<xf applyAlignment="'.$applyAlignment.'" applyBorder="'.$applyBorder.'" applyFont="'.$applyFont.'" applyProtection="false" borderId="'.($borderIdx).'" fillId="'.($fillIdx).'" fontId="'.($fontIdx).'" numFmtId="'.(164+$v['num_fmt_idx']).'" xfId="0">');
			$file->write('  <alignment horizontal="'.$horizAlignment.'" vertical="'.$vertAlignment.'" textRotation="0" wrapText="'.$wrapText.'" indent="0" shrinkToFit="false"/>');
			$file->write('  <protection locked="true" hidden="false"/>');
			$file->write('</xf>');
		}
		$file->write('</cellXfs>');
		$file->write(   '<cellStyles count="6">');
		$file->write(       '<cellStyle builtinId="0" customBuiltin="false" name="Normal" xfId="0"/>');
		$file->write(       '<cellStyle builtinId="3" customBuiltin="false" name="Comma" xfId="15"/>');
		$file->write(       '<cellStyle builtinId="6" customBuiltin="false" name="Comma [0]" xfId="16"/>');
		$file->write(       '<cellStyle builtinId="4" customBuiltin="false" name="Currency" xfId="17"/>');
		$file->write(       '<cellStyle builtinId="7" customBuiltin="false" name="Currency [0]" xfId="18"/>');
		$file->write(       '<cellStyle builtinId="5" customBuiltin="false" name="Percent" xfId="19"/>');
		$file->write(   '</cellStyles>');
		$file->write('</styleSheet>');
		$file->close();
		return $temporary_filename;
	}
	protected function buildAppXML()
	{
		$app_xml="";
		$app_xml.='<?xml version="1.0" encoding="UTF-8" standalone="yes"?>'."\n";
		$app_xml.='<Properties xmlns="http://schemas.openxmlformats.org/officeDocument/2006/extended-properties" xmlns:vt="http://schemas.openxmlformats.org/officeDocument/2006/docPropsVTypes">';
		$app_xml.='<TotalTime>0</TotalTime>';
		$app_xml.='<Company>'.self::xmlspecialchars($this->company).'</Company>';
		$app_xml.='</Properties>';
		return $app_xml;
	}
	protected function buildCoreXML()
	{
		$core_xml="";
		$core_xml.='<?xml version="1.0" encoding="UTF-8" standalone="yes"?>'."\n";
		$core_xml.='<cp:coreProperties xmlns:cp="http://schemas.openxmlformats.org/package/2006/metadata/core-properties" xmlns:dc="http://purl.org/dc/elements/1.1/" xmlns:dcmitype="http://purl.org/dc/dcmitype/" xmlns:dcterms="http://purl.org/dc/terms/" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">';
		$core_xml.='<dcterms:created xsi:type="dcterms:W3CDTF">'.date("Y-m-d\TH:i:s.00\Z").'</dcterms:created>';//$date_time = '2014-10-25T15:54:37.00Z';
		$core_xml.='<dc:title>'.self::xmlspecialchars($this->title).'</dc:title>';
		$core_xml.='<dc:subject>'.self::xmlspecialchars($this->subject).'</dc:subject>';
		$core_xml.='<dc:creator>'.self::xmlspecialchars($this->author).'</dc:creator>';
		if (!empty($this->keywords)) {
			$core_xml.='<cp:keywords>'.self::xmlspecialchars(implode (", ", (array)$this->keywords)).'</cp:keywords>';
		}       
		$core_xml.='<dc:description>'.self::xmlspecialchars($this->description).'</dc:description>';        
		$core_xml.='<cp:revision>0</cp:revision>';
		$core_xml.='</cp:coreProperties>';
		return $core_xml;
	}
	protected function buildRelationshipsXML()
	{
		$rels_xml="";
		$rels_xml.='<?xml version="1.0" encoding="UTF-8"?>'."\n";
		$rels_xml.='<Relationships xmlns="http://schemas.openxmlformats.org/package/2006/relationships">';
		$rels_xml.='<Relationship Id="rId1" Type="http://schemas.openxmlformats.org/officeDocument/2006/relationships/officeDocument" Target="xl/workbook.xml"/>';
		$rels_xml.='<Relationship Id="rId2" Type="http://schemas.openxmlformats.org/package/2006/relationships/metadata/core-properties" Target="docProps/core.xml"/>';
		$rels_xml.='<Relationship Id="rId3" Type="http://schemas.openxmlformats.org/officeDocument/2006/relationships/extended-properties" Target="docProps/app.xml"/>';
		$rels_xml.="\n";
		$rels_xml.='</Relationships>';
		return $rels_xml;
	}
	protected function buildWorkbookXML()
	{
		$i=0;
		$workbook_xml="";
		$workbook_xml.='<?xml version="1.0" encoding="UTF-8" standalone="yes"?>'."\n";
		$workbook_xml.='<workbook xmlns="http://schemas.openxmlformats.org/spreadsheetml/2006/main" xmlns:r="http://schemas.openxmlformats.org/officeDocument/2006/relationships">';
		$workbook_xml.='<fileVersion appName="Calc"/><workbookPr backupFile="false" showObjects="all" date1904="false"/><workbookProtection/>';
		$workbook_xml.='<bookViews><workbookView activeTab="0" firstSheet="0" showHorizontalScroll="true" showSheetTabs="true" showVerticalScroll="true" tabRatio="212" windowHeight="8192" windowWidth="16384" xWindow="0" yWindow="0"/></bookViews>';
		$workbook_xml.='<sheets>';
		foreach($this->sheets as $sheet_name=>$sheet) {
			$sheetname = self::sanitize_sheetname($sheet->sheetname);
			$workbook_xml.='<sheet name="'.self::xmlspecialchars($sheetname).'" sheetId="'.($i+1).'" state="visible" r:id="rId'.($i+2).'"/>';
			$i++;
		}
		$workbook_xml.='</sheets>';
		$workbook_xml.='<definedNames>';
		foreach($this->sheets as $sheet_name=>$sheet) {
			if ($sheet->auto_filter) {
				$sheetname = self::sanitize_sheetname($sheet->sheetname);
				$workbook_xml.='<definedName name="_xlnm._FilterDatabase" localSheetId="0" hidden="1">\''.self::xmlspecialchars($sheetname).'\'!$A$1:' . self::xlsCell($sheet->row_count - 1, count($sheet->columns) - 1, true) . '</definedName>';
				$i++;   
			}
		}
		$workbook_xml.='</definedNames>';
		$workbook_xml.='<calcPr iterateCount="100" refMode="A1" iterate="false" iterateDelta="0.001"/></workbook>';
		return $workbook_xml;
	}
	protected function buildWorkbookRelsXML()
	{
		$i=0;
		$wkbkrels_xml="";
		$wkbkrels_xml.='<?xml version="1.0" encoding="UTF-8"?>'."\n";
		$wkbkrels_xml.='<Relationships xmlns="http://schemas.openxmlformats.org/package/2006/relationships">';
		$wkbkrels_xml.='<Relationship Id="rId1" Type="http://schemas.openxmlformats.org/officeDocument/2006/relationships/styles" Target="styles.xml"/>';
		foreach($this->sheets as $sheet_name=>$sheet) {
			$wkbkrels_xml.='<Relationship Id="rId'.($i+2).'" Type="http://schemas.openxmlformats.org/officeDocument/2006/relationships/worksheet" Target="worksheets/'.($sheet->xmlname).'"/>';
			$i++;
		}
		$wkbkrels_xml.="\n";
		$wkbkrels_xml.='</Relationships>';
		return $wkbkrels_xml;
	}
	protected function buildContentTypesXML()
	{
		$content_types_xml="";
		$content_types_xml.='<?xml version="1.0" encoding="UTF-8"?>'."\n";
		$content_types_xml.='<Types xmlns="http://schemas.openxmlformats.org/package/2006/content-types">';
		$content_types_xml.='<Override PartName="/_rels/.rels" ContentType="application/vnd.openxmlformats-package.relationships+xml"/>';
		$content_types_xml.='<Override PartName="/xl/_rels/workbook.xml.rels" ContentType="application/vnd.openxmlformats-package.relationships+xml"/>';
		foreach($this->sheets as $sheet_name=>$sheet) {
			$content_types_xml.='<Override PartName="/xl/worksheets/'.($sheet->xmlname).'" ContentType="application/vnd.openxmlformats-officedocument.spreadsheetml.worksheet+xml"/>';
		}
		$content_types_xml.='<Override PartName="/xl/workbook.xml" ContentType="application/vnd.openxmlformats-officedocument.spreadsheetml.sheet.main+xml"/>';
		$content_types_xml.='<Override PartName="/xl/styles.xml" ContentType="application/vnd.openxmlformats-officedocument.spreadsheetml.styles+xml"/>';
		$content_types_xml.='<Override PartName="/docProps/app.xml" ContentType="application/vnd.openxmlformats-officedocument.extended-properties+xml"/>';
		$content_types_xml.='<Override PartName="/docProps/core.xml" ContentType="application/vnd.openxmlformats-package.core-properties+xml"/>';
		$content_types_xml.="\n";
		$content_types_xml.='</Types>';
		return $content_types_xml;
	}
	//------------------------------------------------------------------
	/*
	 * @param $row_number int, zero based
	 * @param $column_number int, zero based
	 * @param $absolute bool
	 * @return Cell label/coordinates, ex: A1, C3, AA42 (or if $absolute==true: $A$1, $C$3, $AA$42)
	 * */
	public static function xlsCell($row_number, $column_number, $absolute=false)
	{
		$n = $column_number;
		for($r = ""; $n >= 0; $n = intval($n / 26) - 1) {
			$r = chr($n%26 + 0x41) . $r;
		}
		if ($absolute) {
			return '$' . $r . '$' . ($row_number+1);            
		}
		return $r . ($row_number+1);
	}
	//------------------------------------------------------------------
	public static function log($string)
	{
		file_put_contents("php://stderr", date("Y-m-d H:i:s:").rtrim(is_array($string) ? json_encode($string) : $string)."\n");
	}
	//------------------------------------------------------------------
	public static function sanitize_filename($filename) //http://msdn.microsoft.com/en-us/library/aa365247%28VS.85%29.aspx
	{
		$nonprinting = array_map('chr', range(0,31));
		$invalid_chars = array('<', '>', '?', '"', ':', '|', '\\', '/', '*', '&');
		$all_invalids = array_merge($nonprinting,$invalid_chars);
		return str_replace($all_invalids, "", $filename);
	}
	//------------------------------------------------------------------
	public static function sanitize_sheetname($sheetname) 
	{
		static $badchars  = '\\/?*:[]';
		static $goodchars = '        ';
		$sheetname = strtr($sheetname, $badchars, $goodchars);
		$sheetname = substr($sheetname, 0, 31);
		$sheetname = trim(trim(trim($sheetname),"'"));//trim before and after trimming single quotes
		return !empty($sheetname) ? $sheetname : 'Sheet'.((rand()%900)+100);
	}
	//------------------------------------------------------------------
	public static function xmlspecialchars($val)
	{
		//note, badchars does not include \t\n\r (\x09\x0a\x0d)
		static $badchars = "\x00\x01\x02\x03\x04\x05\x06\x07\x08\x0b\x0c\x0e\x0f\x10\x11\x12\x13\x14\x15\x16\x17\x18\x19\x1a\x1b\x1c\x1d\x1e\x1f\x7f";
		static $goodchars = "                              ";
		return strtr(htmlspecialchars($val, ENT_QUOTES | ENT_XML1), $badchars, $goodchars);//strtr appears to be faster than str_replace
	}
	//------------------------------------------------------------------
	public static function array_first_key(array $arr)
	{
		reset($arr);
		$first_key = key($arr);
		return $first_key;
	}
	//------------------------------------------------------------------
	private static function determineNumberFormatType($num_format)
	{
		$num_format = preg_replace("/\[(Black|Blue|Cyan|Green|Magenta|Red|White|Yellow)\]/i", "", $num_format);
		if ($num_format=='GENERAL') return 'n_auto';
		if ($num_format=='@') return 'n_string';
		if ($num_format=='0') return 'n_numeric';
		if (preg_match("/[H]{1,2}:[M]{1,2}/i", $num_format)) return 'n_datetime';
			if (preg_match("/[M]{1,2}:[S]{1,2}/i", $num_format)) return 'n_datetime';
				if (preg_match("/[Y]{2,4}/i", $num_format)) return 'n_date';
				if (preg_match("/[D]{1,2}/i", $num_format)) return 'n_date';
				if (preg_match("/[M]{1,2}/i", $num_format)) return 'n_date';
				if (preg_match("/$/", $num_format)) return 'n_numeric';
				if (preg_match("/%/", $num_format)) return 'n_numeric';
				if (preg_match("/0/", $num_format)) return 'n_numeric';
				return 'n_auto';
			}
	//------------------------------------------------------------------
			private static function numberFormatStandardized($num_format)
			{
				if ($num_format=='money') { $num_format='dollar'; }
				if ($num_format=='number') { $num_format='integer'; }
				if      ($num_format=='string')   $num_format='@';
				else if ($num_format=='integer')  $num_format='0';
				else if ($num_format=='date')     $num_format='YYYY-MM-DD';
				else if ($num_format=='datetime') $num_format='YYYY-MM-DD HH:MM:SS';
					else if ($num_format=='price')    $num_format='#,##0.00';
					else if ($num_format=='dollar')   $num_format='[$$-1009]#,##0.00;[RED]-[$$-1009]#,##0.00';
					else if ($num_format=='euro')     $num_format='#,##0.00 [$€-407];[RED]-#,##0.00 [$€-407]';
					$ignore_until='';
					$escaped = '';
					for($i=0,$ix=strlen($num_format); $i<$ix; $i++)
					{
						$c = $num_format[$i];
						if ($ignore_until=='' && $c=='[')
							$ignore_until=']';
						else if ($ignore_until=='' && $c=='"')
							$ignore_until='"';
						else if ($ignore_until==$c)
							$ignore_until='';
						if ($ignore_until=='' && ($c==' ' || $c=='-'  || $c=='('  || $c==')') && ($i==0 || $num_format[$i-1]!='_'))
							$escaped.= "\\".$c;
						else
							$escaped.= $c;
					}
					return $escaped;
				}
	//------------------------------------------------------------------
				public static function add_to_list_get_index(&$haystack, $needle)
				{
					$existing_idx = array_search($needle, $haystack, $strict=true);
					if ($existing_idx===false)
					{
						$existing_idx = count($haystack);
						$haystack[] = $needle;
					}
					return $existing_idx;
				}
	//------------------------------------------------------------------
	public static function convert_date_time($date_input) //thanks to Excel::Writer::XLSX::Worksheet.pm (perl)
	{
		$days    = 0;    # Number of days since epoch
		$seconds = 0;    # Time expressed as fraction of 24h hours in seconds
		$year=$month=$day=0;
		$hour=$min  =$sec=0;
		$date_time = $date_input;
		if (preg_match("/(\d{4})\-(\d{2})\-(\d{2})/", $date_time, $matches))
		{
			list($junk,$year,$month,$day) = $matches;
		}
		if (preg_match("/(\d+):(\d{2}):(\d{2})/", $date_time, $matches))
			{
				list($junk,$hour,$min,$sec) = $matches;
				$seconds = ( $hour * 60 * 60 + $min * 60 + $sec ) / ( 24 * 60 * 60 );
			}
		//using 1900 as epoch, not 1904, ignoring 1904 special case
		# Special cases for Excel.
		if ("$year-$month-$day"=='1899-12-31')  return $seconds      ;    # Excel 1900 epoch
		if ("$year-$month-$day"=='1900-01-00')  return $seconds      ;    # Excel 1900 epoch
		if ("$year-$month-$day"=='1900-02-29')  return 60 + $seconds ;    # Excel false leapday
		# We calculate the date by calculating the number of days since the epoch
		# and adjust for the number of leap days. We calculate the number of leap
		# days by normalising the year in relation to the epoch. Thus the year 2000
		# becomes 100 for 4 and 100 year leapdays and 400 for 400 year leapdays.
		$epoch  = 1900;
		$offset = 0;
		$norm   = 300;
		$range  = $year - $epoch;
		# Set month days and check for leap year.
		$leap = (($year % 400 == 0) || (($year % 4 == 0) && ($year % 100)) ) ? 1 : 0;
		$mdays = array( 31, ($leap ? 29 : 28), 31, 30, 31, 30, 31, 31, 30, 31, 30, 31 );
		# Some boundary checks
		if($year < $epoch || $year > 9999) return 0;
		if($month < 1     || $month > 12)  return 0;
		if($day < 1       || $day > $mdays[ $month - 1 ]) return 0;
		# Accumulate the number of days since the epoch.
		$days = $day;    # Add days for current month
		$days += array_sum( array_slice($mdays, 0, $month-1 ) );    # Add days for past months
		$days += $range * 365;                      # Add days for past years
		$days += intval( ( $range ) / 4 );             # Add leapdays
		$days -= intval( ( $range + $offset ) / 100 ); # Subtract 100 year leapdays
		$days += intval( ( $range + $offset + $norm ) / 400 );  # Add 400 year leapdays
		$days -= $leap;                                      # Already counted above
		# Adjust for Excel erroneously treating 1900 as a leap year.
		if ($days > 59) { $days++;}
		return $days + $seconds;
	}
	//------------------------------------------------------------------
}

class XLSXWriter_BuffererWriter
{
	protected $fd=null;
	protected $buffer='';
	protected $check_utf8=false;
	public function __construct($filename, $fd_fopen_flags='w', $check_utf8=false)
	{
		$this->check_utf8 = $check_utf8;
		$this->fd = fopen($filename, $fd_fopen_flags);
		if ($this->fd===false) {
			XLSXWriter::log("Unable to open $filename for writing.");
		}
	}
	public function write($string)
	{
		$this->buffer.=$string;
		if (isset($this->buffer[8191])) {
			$this->purge();
		}
	}
	protected function purge()
	{
		if ($this->fd) {
			if ($this->check_utf8 && !self::isValidUTF8($this->buffer)) {
				XLSXWriter::log("Error, invalid UTF8 encoding detected.");
				$this->check_utf8 = false;
			}
			fwrite($this->fd, $this->buffer);
			$this->buffer='';
		}
	}
	public function close()
	{
		$this->purge();
		if ($this->fd) {
			fclose($this->fd);
			$this->fd=null;
		}
	}
	public function __destruct()
	{
		$this->close();
	}
	public function ftell()
	{
		if ($this->fd) {
			$this->purge();
			return ftell($this->fd);
		}
		return -1;
	}
	public function fseek($pos)
	{
		if ($this->fd) {
			$this->purge();
			return fseek($this->fd, $pos);
		}
		return -1;
	}
	protected static function isValidUTF8($string)
	{
		if (function_exists('mb_check_encoding'))
		{
			return mb_check_encoding($string, 'UTF-8') ? true : false;
		}
		return preg_match("//u", $string) ? true : false;
	}
}