<?php
/**
 * PHPExcel
 *
 * Copyright (c) 2006 - 2015 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_Writer_Excel2007
 * @copyright  Copyright (c) 2006 - 2015 PHPExcel (http://www.codeplex.com/PHPExcel)
 * @license    http://www.gnu.org/licenses/old-licenses/lgpl-2.1.txt    LGPL
 * @version    ##VERSION##, ##DATE##
 */


/**
 * PHPExcel_Writer_Excel2007_Worksheet
 *
 * @category   PHPExcel
 * @package    PHPExcel_Writer_Excel2007
 * @copyright  Copyright (c) 2006 - 2015 PHPExcel (http://www.codeplex.com/PHPExcel)
 */
class PHPExcel_Writer_Excel2007_Worksheet extends PHPExcel_Writer_Excel2007_WriterPart
{
    /**
     * Write worksheet to XML format
     *
     * @param    PHPExcel_Worksheet        $pSheet
     * @param    string[]                $pStringTable
     * @param    boolean                    $includeCharts    Flag indicating if we should write charts
     * @return    string                    XML Output
     * @throws    PHPExcel_Writer_Exception
     */
    public function writeWorksheet($pSheet = null, $pStringTable = null, $includeCharts = FALSE)
    {
        if (!is_null($pSheet)) {
            // Create XML writer
            $objWriter = null;
            if ($this->getParentWriter()->getUseDiskCaching()) {
                $objWriter = new PHPExcel_Shared_XMLWriter(PHPExcel_Shared_XMLWriter::STORAGE_DISK, $this->getParentWriter()->getDiskCachingDirectory());
            } else {
                $objWriter = new PHPExcel_Shared_XMLWriter(PHPExcel_Shared_XMLWriter::STORAGE_MEMORY);
            }

            // XML header
            $objWriter->startDocument('1.0', 'UTF-8', 'yes');

            // Worksheet
            $objWriter->startElement('worksheet');
            $objWriter->writeAttribute('xml:space', 'preserve');
            $objWriter->writeAttribute('xmlns', 'http://schemas.openxmlformats.org/spreadsheetml/2006/main');
            $objWriter->writeAttribute('xmlns:r', 'http://schemas.openxmlformats.org/officeDocument/2006/relationships');

                // sheetPr
                $this->_writeSheetPr($objWriter, $pSheet);

                // Dimension
                $this->_writeDimension($objWriter, $pSheet);

                // sheetViews
                $this->_writeSheetViews($objWriter, $pSheet);

                // sheetFormatPr
                $this->_writeSheetFormatPr($objWriter, $pSheet);

                // cols
                $this->_writeCols($objWriter, $pSheet);

                // sheetData
                $this->_writeSheetData($objWriter, $pSheet, $pStringTable);

                // sheetProtection
                $this->_writeSheetProtection($objWriter, $pSheet);

                // protectedRanges
                $this->_writeProtectedRanges($objWriter, $pSheet);

                // autoFilter
                $this->_writeAutoFilter($objWriter, $pSheet);

                // mergeCells
                $this->_writeMergeCells($objWriter, $pSheet);

                // conditionalFormatting
                $this->_writeConditionalFormatting($objWriter, $pSheet);

                // dataValidations
                $this->_writeDataValidations($objWriter, $pSheet);

                // hyperlinks
                $this->_writeHyperlinks($objWriter, $pSheet);

                // Print options
                $this->_writePrintOptions($objWriter, $pSheet);

                // Page margins
                $this->_writePageMargins($objWriter, $pSheet);

                // Page setup
                $this->_writePageSetup($objWriter, $pSheet);

                // Header / footer
                $this->_writeHeaderFooter($objWriter, $pSheet);

                // Breaks
                $this->_writeBreaks($objWriter, $pSheet);

                // Drawings and/or Charts
                $this->_writeDrawings($objWriter, $pSheet, $includeCharts);

                // LegacyDrawing
                $this->_writeLegacyDrawing($objWriter, $pSheet);

                // LegacyDrawingHF
                $this->_writeLegacyDrawingHF($objWriter, $pSheet);

            $objWriter->endElement();

            // Return
            return $objWriter->getData();
        } else {
            throw new PHPExcel_Writer_Exception("Invalid PHPExcel_Worksheet object passed.");
        }
    }

    /**
     * Write SheetPr
     *
     * @param    PHPExcel_Shared_XMLWriter        $objWriter        XML Writer
     * @param    PHPExcel_Worksheet                $pSheet            Worksheet
     * @throws    PHPExcel_Writer_Exception
     */
    private function _writeSheetPr(PHPExcel_Shared_XMLWriter $objWriter = null, PHPExcel_Worksheet $pSheet = null)
    {
        // sheetPr
        $objWriter->startElement('sheetPr');
        //$objWriter->writeAttribute('codeName',        $pSheet->getTitle());
        if ($pSheet->getParent()->hasMacros()) {//if the workbook have macros, we need to have codeName for the sheet
            if ($pSheet->hasCodeName()==false) {
                $pSheet->setCodeName($pSheet->getTitle());
            }
            $objWriter->writeAttribute('codeName',        $pSheet->getCodeName());
        }
            $autoFilterRange = $pSheet->getAutoFilter()->getRange();
            if (!empty($autoFilterRange)) {
                $objWriter->writeAttribute('filterMode', 1);
                $pSheet->getAutoFilter()->showHideRows();
            }

            // tabColor
            if ($pSheet->isTabColorSet()) {
                $objWriter->startElement('tabColor');
                $objWriter->writeAttribute('rgb',    $pSheet->getTabColor()->getARGB());
                $objWriter->endElement();
            }

            // outlinePr
            $objWriter->startElement('outlinePr');
            $objWriter->writeAttribute('summaryBelow',    ($pSheet->getShowSummaryBelow() ? '1' : '0'));
            $objWriter->writeAttribute('summaryRight',    ($pSheet->getShowSummaryRight() ? '1' : '0'));
            $objWriter->endElement();

            // pageSetUpPr
            if ($pSheet->getPageSetup()->getFitToPage()) {
                $objWriter->startElement('pageSetUpPr');
                $objWriter->writeAttribute('fitToPage',    '1');
                $objWriter->endElement();
            }

        $objWriter->endElement();
    }

    /**
     * Write Dimension
     *
     * @param    PHPExcel_Shared_XMLWriter    $objWriter        XML Writer
     * @param    PHPExcel_Worksheet            $pSheet            Worksheet
     * @throws    PHPExcel_Writer_Exception
     */
    private function _writeDimension(PHPExcel_Shared_XMLWriter $objWriter = null, PHPExcel_Worksheet $pSheet = null)
    {
        // dimension
        $objWriter->startElement('dimension');
        $objWriter->writeAttribute('ref', $pSheet->calculateWorksheetDimension());
        $objWriter->endElement();
    }

    /**
     * Write SheetViews
     *
     * @param    PHPExcel_Shared_XMLWriter            $objWriter        XML Writer
     * @param    PHPExcel_Worksheet                    $pSheet            Worksheet
     * @throws    PHPExcel_Writer_Exception
     */
    private function _writeSheetViews(PHPExcel_Shared_XMLWriter $objWriter = NULL, PHPExcel_Worksheet $pSheet = NULL)
    {
        // sheetViews
        $objWriter->startElement('sheetViews');

            // Sheet selected?
            $sheetSelected = false;
            if ($this->getParentWriter()->getPHPExcel()->getIndex($pSheet) == $this->getParentWriter()->getPHPExcel()->getActiveSheetIndex())
                $sheetSelected = true;


            // sheetView
            $objWriter->startElement('sheetView');
            $objWriter->writeAttribute('tabSelected',        $sheetSelected ? '1' : '0');
            $objWriter->writeAttribute('workbookViewId',    '0');

                // Zoom scales
                if ($pSheet->getSheetView()->getZoomScale() != 100) {
                    $objWriter->writeAttribute('zoomScale',    $pSheet->getSheetView()->getZoomScale());
                }
                if ($pSheet->getSheetView()->getZoomScaleNormal() != 100) {
                    $objWriter->writeAttribute('zoomScaleNormal',    $pSheet->getSheetView()->getZoomScaleNormal());
                }

                // View Layout Type
                if ($pSheet->getSheetView()->getView() !== PHPExcel_Worksheet_SheetView::SHEETVIEW_NORMAL) {
                    $objWriter->writeAttribute('view',    $pSheet->getSheetView()->getView());
                }

                // Gridlines
                if ($pSheet->getShowGridlines()) {
                    $objWriter->writeAttribute('showGridLines',    'true');
                } else {
                    $objWriter->writeAttribute('showGridLines',    'false');
                }

                // Row and column headers
                if ($pSheet->getShowRowColHeaders()) {
                    $objWriter->writeAttribute('showRowColHeaders', '1');
                } else {
                    $objWriter->writeAttribute('showRowColHeaders', '0');
                }

                // Right-to-left
                if ($pSheet->getRightToLeft()) {
                    $objWriter->writeAttribute('rightToLeft',    'true');
                }

                $activeCell = $pSheet->getActiveCell();

                // Pane
                $pane = '';
                $topLeftCell = $pSheet->getFreezePane();
                if (($topLeftCell != '') && ($topLeftCell != 'A1')) {
                    $activeCell = $topLeftCell;
                    // Calculate freeze coordinates
                    $xSplit = $ySplit = 0;

                    list($xSplit, $ySplit) = PHPExcel_Cell::coordinateFromString($topLeftCell);
                    $xSplit = PHPExcel_Cell::columnIndexFromString($xSplit);

                    // pane
                    $pane = 'topRight';
                    $objWriter->startElement('pane');
                    if ($xSplit > 1)
                        $objWriter->writeAttribute('xSplit',    $xSplit - 1);
                    if ($ySplit > 1) {
                        $objWriter->writeAttribute('ySplit',    $ySplit - 1);
                        $pane = ($xSplit > 1) ? 'bottomRight' : 'bottomLeft';
                    }
                    $objWriter->writeAttribute('topLeftCell',    $topLeftCell);
                    $objWriter->writeAttribute('activePane',    $pane);
                    $objWriter->writeAttribute('state',        'frozen');
                    $objWriter->endElement();

                    if (($xSplit > 1) && ($ySplit > 1)) {
                        //    Write additional selections if more than two panes (ie both an X and a Y split)
                        $objWriter->startElement('selection');    $objWriter->writeAttribute('pane', 'topRight');        $objWriter->endElement();
                        $objWriter->startElement('selection');    $objWriter->writeAttribute('pane', 'bottomLeft');    $objWriter->endElement();
                    }
                }

                // Selection
//                if ($pane != '') {
                    //    Only need to write selection element if we have a split pane
                    //        We cheat a little by over-riding the active cell selection, setting it to the split cell
                    $objWriter->startElement('selection');
                    if ($pane != '') {
                        $objWriter->writeAttribute('pane', $pane);
                    }
                    $objWriter->writeAttribute('activeCell', $activeCell);
                    $objWriter->writeAttribute('sqref', $activeCell);
                    $objWriter->endElement();
//                }

            $objWriter->endElement();

        $objWriter->endElement();
    }

    /**
     * Write SheetFormatPr
     *
     * @param    PHPExcel_Shared_XMLWriter $objWriter        XML Writer
     * @param    PHPExcel_Worksheet          $pSheet            Worksheet
     * @throws    PHPExcel_Writer_Exception
     */
    private function _writeSheetFormatPr(PHPExcel_Shared_XMLWriter $objWriter = null, PHPExcel_Worksheet $pSheet = null)
    {
        // sheetFormatPr
        $objWriter->startElement('sheetFormatPr');

            // Default row height
            if ($pSheet->getDefaultRowDimension()->getRowHeight() >= 0) {
                $objWriter->writeAttribute('customHeight',        'true');
                $objWriter->writeAttribute('defaultRowHeight',    PHPExcel_Shared_String::FormatNumber($pSheet->getDefaultRowDimension()->getRowHeight()));
            } else {
                $objWriter->writeAttribute('defaultRowHeight', '14.4');
            }

            // Set Zero Height row
            if ((string)$pSheet->getDefaultRowDimension()->getZeroHeight()  == '1' ||
                strtolower((string)$pSheet->getDefaultRowDimension()->getZeroHeight()) == 'true' ) {
                $objWriter->writeAttribute('zeroHeight', '1');
            }

            // Default column width
            if ($pSheet->getDefaultColumnDimension()->getWidth() >= 0) {
                $objWriter->writeAttribute('defaultColWidth', PHPExcel_Shared_String::FormatNumber($pSheet->getDefaultColumnDimension()->getWidth()));
            }

            // Outline level - row
            $outlineLevelRow = 0;
            foreach ($pSheet->getRowDimensions() as $dimension) {
                if ($dimension->getOutlineLevel() > $outlineLevelRow) {
                    $outlineLevelRow = $dimension->getOutlineLevel();
                }
            }
            $objWriter->writeAttribute('outlineLevelRow',    (int)$outlineLevelRow);

            // Outline level - column
            $outlineLevelCol = 0;
            foreach ($pSheet->getColumnDimensions() as $dimension) {
                if ($dimension->getOutlineLevel() > $outlineLevelCol) {
                    $outlineLevelCol = $dimension->getOutlineLevel();
                }
            }
            $objWriter->writeAttribute('outlineLevelCol',    (int)$outlineLevelCol);

        $objWriter->endElement();
    }

    /**
     * Write Cols
     *
     * @param    PHPExcel_Shared_XMLWriter            $objWriter        XML Writer
     * @param    PHPExcel_Worksheet                    $pSheet            Worksheet
     * @throws    PHPExcel_Writer_Exception
     */
    private function _writeCols(PHPExcel_Shared_XMLWriter $objWriter = null, PHPExcel_Worksheet $pSheet = null)
    {
        // cols
        if (count($pSheet->getColumnDimensions()) > 0)  {
            $objWriter->startElement('cols');

                $pSheet->calculateColumnWidths();

                // Loop through column dimensions
                foreach ($pSheet->getColumnDimensions() as $colDimension) {
                    // col
                    $objWriter->startElement('col');
                    $objWriter->writeAttribute('min',    PHPExcel_Cell::columnIndexFromString($colDimension->getColumnIndex()));
                    $objWriter->writeAttribute('max',    PHPExcel_Cell::columnIndexFromString($colDimension->getColumnIndex()));

                    if ($colDimension->getWidth() < 0) {
                        // No width set, apply default of 10
                        $objWriter->writeAttribute('width',        '9.10');
                    } else {
                        // Width set
                        $objWriter->writeAttribute('width',        PHPExcel_Shared_String::FormatNumber($colDimension->getWidth()));
                    }

                    // Column visibility
                    if ($colDimension->getVisible() == false) {
                        $objWriter->writeAttribute('hidden',        'true');
                    }

                    // Auto size?
                    if ($colDimension->getAutoSize()) {
                        $objWriter->writeAttribute('bestFit',        'true');
                    }

                    // Custom width?
                    if ($colDimension->getWidth() != $pSheet->getDefaultColumnDimension()->getWidth()) {
                        $objWriter->writeAttribute('customWidth',    'true');
                    }

                    // Collapsed
                    if ($colDimension->getCollapsed() == true) {
                        $objWriter->writeAttribute('collapsed',        'true');
                    }

                    // Outline level
                    if ($colDimension->getOutlineLevel() > 0) {
                        $objWriter->writeAttribute('outlineLevel',    $colDimension->getOutlineLevel());
                    }

                    // Style
                    $objWriter->writeAttribute('style', $colDimension->getXfIndex());

                    $objWriter->endElement();
                }

            $objWriter->endElement();
        }
    }

    /**
     * Write SheetProtection
     *
     * @param    PHPExcel_Shared_XMLWriter            $objWriter        XML Writer
     * @param    PHPExcel_Worksheet                    $pSheet            Worksheet
     * @throws    PHPExcel_Writer_Exception
     */
    private function _writeSheetProtection(PHPExcel_Shared_XMLWriter $objWriter = null, PHPExcel_Worksheet $pSheet = null)
    {
        // sheetProtection
        $objWriter->startElement('sheetProtection');

        if ($pSheet->getProtection()->getPassword() != '') {
            $objWriter->writeAttribute('password',                $pSheet->getProtection()->getPassword());
        }

        $objWriter->writeAttribute('sheet',                    ($pSheet->getProtection()->getSheet()                ? 'true' : 'false'));
        $objWriter->writeAttribute('objects',                ($pSheet->getProtection()->getObjects()                ? 'true' : 'false'));
        $objWriter->writeAttribute('scenarios',                ($pSheet->getProtection()->getScenarios()            ? 'true' : 'false'));
        $objWriter->writeAttribute('formatCells',            ($pSheet->getProtection()->getFormatCells()            ? 'true' : 'false'));
        $objWriter->writeAttribute('formatColumns',            ($pSheet->getProtection()->getFormatColumns()        ? 'true' : 'false'));
        $objWriter->writeAttribute('formatRows',            ($pSheet->getProtection()->getFormatRows()            ? 'true' : 'false'));
        $objWriter->writeAttribute('insertColumns',            ($pSheet->getProtection()->getInsertColumns()        ? 'true' : 'false'));
        $objWriter->writeAttribute('insertRows',            ($pSheet->getProtection()->getInsertRows()            ? 'true' : 'false'));
        $objWriter->writeAttribute('insertHyperlinks',        ($pSheet->getProtection()->getInsertHyperlinks()    ? 'true' : 'false'));
        $objWriter->writeAttribute('deleteColumns',            ($pSheet->getProtection()->getDeleteColumns()        ? 'true' : 'false'));
        $objWriter->writeAttribute('deleteRows',            ($pSheet->getProtection()->getDeleteRows()            ? 'true' : 'false'));
        $objWriter->writeAttribute('selectLockedCells',        ($pSheet->getProtection()->getSelectLockedCells()    ? 'true' : 'false'));
        $objWriter->writeAttribute('sort',                    ($pSheet->getProtection()->getSort()                ? 'true' : 'false'));
        $objWriter->writeAttribute('autoFilter',            ($pSheet->getProtection()->getAutoFilter()            ? 'true' : 'false'));
        $objWriter->writeAttribute('pivotTables',            ($pSheet->getProtection()->getPivotTables()            ? 'true' : 'false'));
        $objWriter->writeAttribute('selectUnlockedCells',    ($pSheet->getProtection()->getSelectUnlockedCells()    ? 'true' : 'false'));
        $objWriter->endElement();
    }

    /**
     * Write ConditionalFormatting
     *
     * @param    PHPExcel_Shared_XMLWriter            $objWriter        XML Writer
     * @param    PHPExcel_Worksheet                    $pSheet            Worksheet
     * @throws    PHPExcel_Writer_Exception
     */
    private function _writeConditionalFormatting(PHPExcel_Shared_XMLWriter $objWriter = null, PHPExcel_Worksheet $pSheet = null)
    {
        // Conditional id
        $id = 1;

        // Loop through styles in the current worksheet
        foreach ($pSheet->getConditionalStylesCollection() as $cellCoordinate => $conditionalStyles) {
            foreach ($conditionalStyles as $conditional) {
                // WHY was this again?
                // if ($this->getParentWriter()->getStylesConditionalHashTable()->getIndexForHashCode( $conditional->getHashCode() ) == '') {
                //    continue;
                // }
                if ($conditional->getConditionType() != PHPExcel_Style_Conditional::CONDITION_NONE) {
                    // conditionalFormatting
                    $objWriter->startElement('conditionalFormatting');
                    $objWriter->writeAttribute('sqref',    $cellCoordinate);

                        // cfRule
                        $objWriter->startElement('cfRule');
                        $objWriter->writeAttribute('type',        $conditional->getConditionType());
                        $objWriter->writeAttribute('dxfId',        $this->getParentWriter()->getStylesConditionalHashTable()->getIndexForHashCode( $conditional->getHashCode() ));
                        $objWriter->writeAttribute('priority',    $id++);

                        if (($conditional->getConditionType() == PHPExcel_Style_Conditional::CONDITION_CELLIS
                                ||
                             $conditional->getConditionType() == PHPExcel_Style_Conditional::CONDITION_CONTAINSTEXT)
                            && $conditional->getOperatorType() != PHPExcel_Style_Conditional::OPERATOR_NONE) {
                            $objWriter->writeAttribute('operator',    $conditional->getOperatorType());
                        }

                        if ($conditional->getConditionType() == PHPExcel_Style_Conditional::CONDITION_CONTAINSTEXT
                            && !is_null($conditional->getText())) {
                            $objWriter->writeAttribute('text',    $conditional->getText());
                        }

                        if ($conditional->getConditionType() == PHPExcel_Style_Conditional::CONDITION_CONTAINSTEXT
                            && $conditional->getOperatorType() == PHPExcel_Style_Conditional::OPERATOR_CONTAINSTEXT
                            && !is_null($conditional->getText())) {
                            $objWriter->writeElement('formula',    'NOT(ISERROR(SEARCH("' . $conditional->getText() . '",' . $cellCoordinate . ')))');
                        } else if ($conditional->getConditionType() == PHPExcel_Style_Conditional::CONDITION_CONTAINSTEXT
                            && $conditional->getOperatorType() == PHPExcel_Style_Conditional::OPERATOR_BEGINSWITH
                            && !is_null($conditional->getText())) {
                            $objWriter->writeElement('formula',    'LEFT(' . $cellCoordinate . ',' . strlen($conditional->getText()) . ')="' . $conditional->getText() . '"');
                        } else if ($conditional->getConditionType() == PHPExcel_Style_Conditional::CONDITION_CONTAINSTEXT
                            && $conditional->getOperatorType() == PHPExcel_Style_Conditional::OPERATOR_ENDSWITH
                            && !is_null($conditional->getText())) {
                            $objWriter->writeElement('formula',    'RIGHT(' . $cellCoordinate . ',' . strlen($conditional->getText()) . ')="' . $conditional->getText() . '"');
                        } else if ($conditional->getConditionType() == PHPExcel_Style_Conditional::CONDITION_CONTAINSTEXT
                            && $conditional->getOperatorType() == PHPExcel_Style_Conditional::OPERATOR_NOTCONTAINS
                            && !is_null($conditional->getText())) {
                            $objWriter->writeElement('formula',    'ISERROR(SEARCH("' . $conditional->getText() . '",' . $cellCoordinate . '))');
                        } else if ($conditional->getConditionType() == PHPExcel_Style_Conditional::CONDITION_CELLIS
                            || $conditional->getConditionType() == PHPExcel_Style_Conditional::CONDITION_CONTAINSTEXT
                            || $conditional->getConditionType() == PHPExcel_Style_Conditional::CONDITION_EXPRESSION) {
                            foreach ($conditional->getConditions() as $formula) {
                                // Formula
                                $objWriter->writeElement('formula',    $formula);
                            }
                        }

                        $objWriter->endElement();

                    $objWriter->endElement();
                }
            }
        }
    }

    /**
     * Write DataValidations
     *
     * @param    PHPExcel_Shared_XMLWriter            $objWriter        XML Writer
     * @param    PHPExcel_Worksheet                    $pSheet            Worksheet
     * @throws    PHPExcel_Writer_Exception
     */
    private function _writeDataValidations(PHPExcel_Shared_XMLWriter $objWriter = null, PHPExcel_Worksheet $pSheet = null)
    {
        // Datavalidation collection
        $dataValidationCollection = $pSheet->getDataValidationCollection();

        // Write data validations?
        if (!empty($dataValidationCollection)) {
            $objWriter->startElement('dataValidations');
            $objWriter->writeAttribute('count', count($dataValidationCollection));

            foreach ($dataValidationCollection as $coordinate => $dv) {
                $objWriter->startElement('dataValidation');

                if ($dv->getType() != '') {
                    $objWriter->writeAttribute('type', $dv->getType());
                }

                if ($dv->getErrorStyle() != '') {
                    $objWriter->writeAttribute('errorStyle', $dv->getErrorStyle());
                }

                if ($dv->getOperator() != '') {
                    $objWriter->writeAttribute('operator', $dv->getOperator());
                }

                $objWriter->writeAttribute('allowBlank',        ($dv->getAllowBlank()        ? '1'  : '0'));
                $objWriter->writeAttribute('showDropDown',        (!$dv->getShowDropDown()    ? '1'  : '0'));
                $objWriter->writeAttribute('showInputMessage',    ($dv->getShowInputMessage()    ? '1'  : '0'));
                $objWriter->writeAttribute('showErrorMessage',    ($dv->getShowErrorMessage()    ? '1'  : '0'));

                if ($dv->getErrorTitle() !== '') {
                    $objWriter->writeAttribute('errorTitle', $dv->getErrorTitle());
                }
                if ($dv->getError() !== '') {
                    $objWriter->writeAttribute('error', $dv->getError());
                }
                if ($dv->getPromptTitle() !== '') {
                    $objWriter->writeAttribute('promptTitle', $dv->getPromptTitle());
                }
                if ($dv->getPrompt() !== '') {
                    $objWriter->writeAttribute('prompt', $dv->getPrompt());
                }

                $objWriter->writeAttribute('sqref', $coordinate);

                if ($dv->getFormula1() !== '') {
                    $objWriter->writeElement('formula1', $dv->getFormula1());
                }
                if ($dv->getFormula2() !== '') {
                    $objWriter->writeElement('formula2', $dv->getFormula2());
                }

                $objWriter->endElement();
            }

            $objWriter->endElement();
        }
    }

    /**
     * Write Hyperlinks
     *
     * @param    PHPExcel_Shared_XMLWriter            $objWriter        XML Writer
     * @param    PHPExcel_Worksheet                    $pSheet            Worksheet
     * @throws    PHPExcel_Writer_Exception
     */
    private function _writeHyperlinks(PHPExcel_Shared_XMLWriter $objWriter = null, PHPExcel_Worksheet $pSheet = null)
    {
        // Hyperlink collection
        $hyperlinkCollection = $pSheet->getHyperlinkCollection();

        // Relation ID
        $relationId = 1;

        // Write hyperlinks?
        if (!empty($hyperlinkCollection)) {
            $objWriter->startElement('hyperlinks');

            foreach ($hyperlinkCollection as $coordinate => $hyperlink) {
                $objWriter->startElement('hyperlink');

                $objWriter->writeAttribute('ref', $coordinate);
                if (!$hyperlink->isInternal()) {
                    $objWriter->writeAttribute('r:id',    'rId_hyperlink_' . $relationId);
                    ++$relationId;
                } else {
                    $objWriter->writeAttribute('location',    str_replace('sheet://', '', $hyperlink->getUrl()));
                }

                if ($hyperlink->getTooltip() != '') {
                    $objWriter->writeAttribute('tooltip', $hyperlink->getTooltip());
                }

                $objWriter->endElement();
            }

            $objWriter->endElement();
        }
    }

    /**
     * Write ProtectedRanges
     *
     * @param    PHPExcel_Shared_XMLWriter            $objWriter        XML Writer
     * @param    PHPExcel_Worksheet                    $pSheet            Worksheet
     * @throws    PHPExcel_Writer_Exception
     */
    private function _writeProtectedRanges(PHPExcel_Shared_XMLWriter $objWriter = null, PHPExcel_Worksheet $pSheet = null)
    {
        if (count($pSheet->getProtectedCells()) > 0) {
            // protectedRanges
            $objWriter->startElement('protectedRanges');

                // Loop protectedRanges
                foreach ($pSheet->getProtectedCells() as $protectedCell => $passwordHash) {
                    // protectedRange
                    $objWriter->startElement('protectedRange');
                    $objWriter->writeAttribute('name',        'p' . md5($protectedCell));
                    $objWriter->writeAttribute('sqref',    $protectedCell);
                    if (!empty($passwordHash)) {
                        $objWriter->writeAttribute('password',    $passwordHash);
                    }
                    $objWriter->endElement();
                }

            $objWriter->endElement();
        }
    }

    /**
     * Write MergeCells
     *
     * @param    PHPExcel_Shared_XMLWriter            $objWriter        XML Writer
     * @param    PHPExcel_Worksheet                    $pSheet            Worksheet
     * @throws    PHPExcel_Writer_Exception
     */
    private function _writeMergeCells(PHPExcel_Shared_XMLWriter $objWriter = null, PHPExcel_Worksheet $pSheet = null)
    {
        if (count($pSheet->getMergeCells()) > 0) {
            // mergeCells
            $objWriter->startElement('mergeCells');

                // Loop mergeCells
                foreach ($pSheet->getMergeCells() as $mergeCell) {
                    // mergeCell
                    $objWriter->startElement('mergeCell');
                    $objWriter->writeAttribute('ref', $mergeCell);
                    $objWriter->endElement();
                }

            $objWriter->endElement();
        }
    }

    /**
     * Write PrintOptions
     *
     * @param    PHPExcel_Shared_XMLWriter            $objWriter        XML Writer
     * @param    PHPExcel_Worksheet                    $pSheet            Worksheet
     * @throws    PHPExcel_Writer_Exception
     */
    private function _writePrintOptions(PHPExcel_Shared_XMLWriter $objWriter = null, PHPExcel_Worksheet $pSheet = null)
    {
        // printOptions
        $objWriter->startElement('printOptions');

        $objWriter->writeAttribute('gridLines',    ($pSheet->getPrintGridlines() ? 'true': 'false'));
        $objWriter->writeAttribute('gridLinesSet',    'true');

        if ($pSheet->getPageSetup()->getHorizontalCentered()) {
            $objWriter->writeAttribute('horizontalCentered', 'true');
        }

        if ($pSheet->getPageSetup()->getVerticalCentered()) {
            $objWriter->writeAttribute('verticalCentered', 'true');
        }

        $objWriter->endElement();
    }

    /**
     * Write PageMargins
     *
     * @param    PHPExcel_Shared_XMLWriter                $objWriter        XML Writer
     * @param    PHPExcel_Worksheet                        $pSheet            Worksheet
     * @throws    PHPExcel_Writer_Exception
     */
    private function _writePageMargins(PHPExcel_Shared_XMLWriter $objWriter = null, PHPExcel_Worksheet $pSheet = null)
    {
        // pageMargins
        $objWriter->startElement('pageMargins');
        $objWriter->writeAttribute('left',        PHPExcel_Shared_String::FormatNumber($pSheet->getPageMargins()->getLeft()));
        $objWriter->writeAttribute('right',        PHPExcel_Shared_String::FormatNumber($pSheet->getPageMargins()->getRight()));
        $objWriter->writeAttribute('top',        PHPExcel_Shared_String::FormatNumber($pSheet->getPageMargins()->getTop()));
        $objWriter->writeAttribute('bottom',    PHPExcel_Shared_String::FormatNumber($pSheet->getPageMargins()->getBottom()));
        $objWriter->writeAttribute('header',    PHPExcel_Shared_String::FormatNumber($pSheet->getPageMargins()->getHeader()));
        $objWriter->writeAttribute('footer',    PHPExcel_Shared_String::FormatNumber($pSheet->getPageMargins()->getFooter()));
        $objWriter->endElement();
    }

    /**
     * Write AutoFilter
     *
     * @param    PHPExcel_Shared_XMLWriter                $objWriter        XML Writer
     * @param    PHPExcel_Worksheet                        $pSheet            Worksheet
     * @throws    PHPExcel_Writer_Exception
     */
    private function _writeAutoFilter(PHPExcel_Shared_XMLWriter $objWriter = null, PHPExcel_Worksheet $pSheet = null)
    {
        $autoFilterRange = $pSheet->getAutoFilter()->getRange();
        if (!empty($autoFilterRange)) {
            // autoFilter
            $objWriter->startElement('autoFilter');

            // Strip any worksheet reference from the filter coordinates
            $range = PHPExcel_Cell::splitRange($autoFilterRange);
            $range = $range[0];
            //    Strip any worksheet ref
            if (strpos($range[0],'!') !== false) {
                list($ws, $range[0]) = explode('!', $range[0]);
            }
            $range = implode(':', $range);

            $objWriter->writeAttribute('ref',    str_replace('$','', $range));

            $columns = $pSheet->getAutoFilter()->getColumns();
            if (count($columns > 0)) {
                foreach ($columns as $columnID => $column) {
                    $rules = $column->getRules();
                    if (count($rules > 0)) {
                        $objWriter->startElement('filterColumn');
                            $objWriter->writeAttribute('colId',    $pSheet->getAutoFilter()->getColumnOffset($columnID));

                            $objWriter->startElement( $column->getFilterType());
                                if ($column->getJoin() == PHPExcel_Worksheet_AutoFilter_Column::AUTOFILTER_COLUMN_JOIN_AND) {
                                    $objWriter->writeAttribute('and',    1);
                                }

                                foreach ($rules as $rule) {
                                    if (($column->getFilterType() === PHPExcel_Worksheet_AutoFilter_Column::AUTOFILTER_FILTERTYPE_FILTER) &&
                                        ($rule->getOperator() === PHPExcel_Worksheet_AutoFilter_Column_Rule::AUTOFILTER_COLUMN_RULE_EQUAL) &&
                                        ($rule->getValue() === '')) {
                                        //    Filter rule for Blanks
                                        $objWriter->writeAttribute('blank',    1);
                                    } elseif ($rule->getRuleType() === PHPExcel_Worksheet_AutoFilter_Column_Rule::AUTOFILTER_RULETYPE_DYNAMICFILTER) {
                                        //    Dynamic Filter Rule
                                        $objWriter->writeAttribute('type', $rule->getGrouping());
                                        $val = $column->getAttribute('val');
                                        if ($val !== NULL) {
                                            $objWriter->writeAttribute('val', $val);
                                        }
                                        $maxVal = $column->getAttribute('maxVal');
                                        if ($maxVal !== NULL) {
                                            $objWriter->writeAttribute('maxVal', $maxVal);
                                        }
                                    } elseif ($rule->getRuleType() === PHPExcel_Worksheet_AutoFilter_Column_Rule::AUTOFILTER_RULETYPE_TOPTENFILTER) {
                                        //    Top 10 Filter Rule
                                        $objWriter->writeAttribute('val',    $rule->getValue());
                                        $objWriter->writeAttribute('percent',    (($rule->getOperator() === PHPExcel_Worksheet_AutoFilter_Column_Rule::AUTOFILTER_COLUMN_RULE_TOPTEN_PERCENT) ? '1' : '0'));
                                        $objWriter->writeAttribute('top',    (($rule->getGrouping() === PHPExcel_Worksheet_AutoFilter_Column_Rule::AUTOFILTER_COLUMN_RULE_TOPTEN_TOP) ? '1': '0'));
                                    } else {
                                        //    Filter, DateGroupItem or CustomFilter
                                        $objWriter->startElement($rule->getRuleType());

                                            if ($rule->getOperator() !== PHPExcel_Worksheet_AutoFilter_Column_Rule::AUTOFILTER_COLUMN_RULE_EQUAL) {
                                                $objWriter->writeAttribute('operator',    $rule->getOperator());
                                            }
                                            if ($rule->getRuleType() === PHPExcel_Worksheet_AutoFilter_Column_Rule::AUTOFILTER_RULETYPE_DATEGROUP) {
                                                // Date Group filters
                                                foreach ($rule->getValue() as $key => $value) {
                                                    if ($value > '') $objWriter->writeAttribute($key,    $value);
                                                }
                                                $objWriter->writeAttribute('dateTimeGrouping',    $rule->getGrouping());
                                            } else {
                                                $objWriter->writeAttribute('val',    $rule->getValue());
                                            }

                                        $objWriter->endElement();
                                    }
                                }

                            $objWriter->endElement();

                        $objWriter->endElement();
                    }
                }
            }

            $objWriter->endElement();
        }
    }

    /**
     * Write PageSetup
     *
     * @param    PHPExcel_Shared_XMLWriter            $objWriter        XML Writer
     * @param    PHPExcel_Worksheet                    $pSheet            Worksheet
     * @throws    PHPExcel_Writer_Exception
     */
    private function _writePageSetup(PHPExcel_Shared_XMLWriter $objWriter = null, PHPExcel_Worksheet $pSheet = null)
    {
        // pageSetup
        $objWriter->startElement('pageSetup');
        $objWriter->writeAttribute('paperSize',        $pSheet->getPageSetup()->getPaperSize());
        $objWriter->writeAttribute('orientation',    $pSheet->getPageSetup()->getOrientation());

        if (!is_null($pSheet->getPageSetup()->getScale())) {
            $objWriter->writeAttribute('scale',                 $pSheet->getPageSetup()->getScale());
        }
        if (!is_null($pSheet->getPageSetup()->getFitToHeight())) {
            $objWriter->writeAttribute('fitToHeight',         $pSheet->getPageSetup()->getFitToHeight());
        } else {
            $objWriter->writeAttribute('fitToHeight',         '0');
        }
        if (!is_null($pSheet->getPageSetup()->getFitToWidth())) {
            $objWriter->writeAttribute('fitToWidth',         $pSheet->getPageSetup()->getFitToWidth());
        } else {
            $objWriter->writeAttribute('fitToWidth',         '0');
        }
        if (!is_null($pSheet->getPageSetup()->getFirstPageNumber())) {
            $objWriter->writeAttribute('firstPageNumber',    $pSheet->getPageSetup()->getFirstPageNumber());
            $objWriter->writeAttribute('useFirstPageNumber', '1');
        }

        $objWriter->endElement();
    }

    /**
     * Write Header / Footer
     *
     * @param    PHPExcel_Shared_XMLWriter        $objWriter        XML Writer
     * @param    PHPExcel_Worksheet                $pSheet            Worksheet
     * @throws    PHPExcel_Writer_Exception
     */
    private function _writeHeaderFooter(PHPExcel_Shared_XMLWriter $objWriter = null, PHPExcel_Worksheet $pSheet = null)
    {
        // headerFooter
        $objWriter->startElement('headerFooter');
        $objWriter->writeAttribute('differentOddEven',    ($pSheet->getHeaderFooter()->getDifferentOddEven() ? 'true' : 'false'));
        $objWriter->writeAttribute('differentFirst',    ($pSheet->getHeaderFooter()->getDifferentFirst() ? 'true' : 'false'));
        $objWriter->writeAttribute('scaleWithDoc',        ($pSheet->getHeaderFooter()->getScaleWithDocument() ? 'true' : 'false'));
        $objWriter->writeAttribute('alignWithMargins',    ($pSheet->getHeaderFooter()->getAlignWithMargins() ? 'true' : 'false'));

            $objWriter->writeElement('oddHeader',        $pSheet->getHeaderFooter()->getOddHeader());
            $objWriter->writeElement('oddFooter',        $pSheet->getHeaderFooter()->getOddFooter());
            $objWriter->writeElement('evenHeader',        $pSheet->getHeaderFooter()->getEvenHeader());
            $objWriter->writeElement('evenFooter',        $pSheet->getHeaderFooter()->getEvenFooter());
            $objWriter->writeElement('firstHeader',    $pSheet->getHeaderFooter()->getFirstHeader());
            $objWriter->writeElement('firstFooter',    $pSheet->getHeaderFooter()->getFirstFooter());
        $objWriter->endElement();
    }

    /**
     * Write Breaks
     *
     * @param    PHPExcel_Shared_XMLWriter        $objWriter        XML Writer
     * @param    PHPExcel_Worksheet                $pSheet            Worksheet
     * @throws    PHPExcel_Writer_Exception
     */
    private function _writeBreaks(PHPExcel_Shared_XMLWriter $objWriter = null, PHPExcel_Worksheet $pSheet = null)
    {
        // Get row and column breaks
        $aRowBreaks = array();
        $aColumnBreaks = array();
        foreach ($pSheet->getBreaks() as $cell => $breakType) {
            if ($breakType == PHPExcel_Worksheet::BREAK_ROW) {
                $aRowBreaks[] = $cell;
            } else if ($breakType == PHPExcel_Worksheet::BREAK_COLUMN) {
                $aColumnBreaks[] = $cell;
            }
        }

        // rowBreaks
        if (!empty($aRowBreaks)) {
            $objWriter->startElement('rowBreaks');
            $objWriter->writeAttribute('count',            count($aRowBreaks));
            $objWriter->writeAttribute('manualBreakCount',    count($aRowBreaks));

                foreach ($aRowBreaks as $cell) {
                    $coords = PHPExcel_Cell::coordinateFromString($cell);

                    $objWriter->startElement('brk');
                    $objWriter->writeAttribute('id',    $coords[1]);
                    $objWriter->writeAttribute('man',    '1');
                    $objWriter->endElement();
                }

            $objWriter->endElement();
        }

        // Second, write column breaks
        if (!empty($aColumnBreaks)) {
            $objWriter->startElement('colBreaks');
            $objWriter->writeAttribute('count',            count($aColumnBreaks));
            $objWriter->writeAttribute('manualBreakCount',    count($aColumnBreaks));

                foreach ($aColumnBreaks as $cell) {
                    $coords = PHPExcel_Cell::coordinateFromString($cell);

                    $objWriter->startElement('brk');
                    $objWriter->writeAttribute('id',    PHPExcel_Cell::columnIndexFromString($coords[0]) - 1);
                    $objWriter->writeAttribute('man',    '1');
                    $objWriter->endElement();
                }

            $objWriter->endElement();
        }
    }

    /**
     * Write SheetData
     *
     * @param    PHPExcel_Shared_XMLWriter        $objWriter        XML Writer
     * @param    PHPExcel_Worksheet                $pSheet            Worksheet
     * @param    string[]                        $pStringTable    String table
     * @throws    PHPExcel_Writer_Exception
     */
    private function _writeSheetData(PHPExcel_Shared_XMLWriter $objWriter = null, PHPExcel_Worksheet $pSheet = null, $pStringTable = null)
    {
        if (is_array($pStringTable)) {
            // Flipped stringtable, for faster index searching
            $aFlippedStringTable = $this->getParentWriter()->getWriterPart('stringtable')->flipStringTable($pStringTable);

            // sheetData
            $objWriter->startElement('sheetData');

                // Get column count
                $colCount = PHPExcel_Cell::columnIndexFromString($pSheet->getHighestColumn());

                // Highest row number
                $highestRow = $pSheet->getHighestRow();

                // Loop through cells
                $cellsByRow = array();
                foreach ($pSheet->getCellCollection() as $cellID) {
                    $cellAddress = PHPExcel_Cell::coordinateFromString($cellID);
                    $cellsByRow[$cellAddress[1]][] = $cellID;
                }

                $currentRow = 0;
                while ($currentRow++ < $highestRow) {
                    // Get row dimension
                    $rowDimension = $pSheet->getRowDimension($currentRow);

                    // Write current row?
                    $writeCurrentRow =    isset($cellsByRow[$currentRow]) ||
                                        $rowDimension->getRowHeight() >= 0 ||
                                        $rowDimension->getVisible() == false ||
                                        $rowDimension->getCollapsed() == true ||
                                        $rowDimension->getOutlineLevel() > 0 ||
                                        $rowDimension->getXfIndex() !== null;

                    if ($writeCurrentRow) {
                        // Start a new row
                        $objWriter->startElement('row');
                        $objWriter->writeAttribute('r',    $currentRow);
                        $objWriter->writeAttribute('spans',    '1:' . $colCount);

                        // Row dimensions
                        if ($rowDimension->getRowHeight() >= 0) {
                            $objWriter->writeAttribute('customHeight',    '1');
                            $objWriter->writeAttribute('ht',            PHPExcel_Shared_String::FormatNumber($rowDimension->getRowHeight()));
                        }

                        // Row visibility
                        if ($rowDimension->getVisible() == false) {
                            $objWriter->writeAttribute('hidden',        'true');
                        }

                        // Collapsed
                        if ($rowDimension->getCollapsed() == true) {
                            $objWriter->writeAttribute('collapsed',        'true');
                        }

                        // Outline level
                        if ($rowDimension->getOutlineLevel() > 0) {
                            $objWriter->writeAttribute('outlineLevel',    $rowDimension->getOutlineLevel());
                        }

                        // Style
                        if ($rowDimension->getXfIndex() !== null) {
                            $objWriter->writeAttribute('s',    $rowDimension->getXfIndex());
                            $objWriter->writeAttribute('customFormat', '1');
                        }

                        // Write cells
                        if (isset($cellsByRow[$currentRow])) {
                            foreach ($cellsByRow[$currentRow] as $cellAddress) {
                                // Write cell
                                $this->_writeCell($objWriter, $pSheet, $cellAddress, $pStringTable, $aFlippedStringTable);
                            }
                        }

                        // End row
                        $objWriter->endElement();
                    }
                }

            $objWriter->endElement();
        } else {
            throw new PHPExcel_Writer_Exception("Invalid parameters passed.");
        }
    }

    /**
     * Write Cell
     *
     * @param    PHPExcel_Shared_XMLWriter    $objWriter                XML Writer
     * @param    PHPExcel_Worksheet            $pSheet                    Worksheet
     * @param    PHPExcel_Cell                $pCellAddress            Cell Address
     * @param    string[]                    $pStringTable            String table
     * @param    string[]                    $pFlippedStringTable    String table (flipped), for faster index searching
     * @throws    PHPExcel_Writer_Exception
     */
    private function _writeCell(PHPExcel_Shared_XMLWriter $objWriter = null, PHPExcel_Worksheet $pSheet = null, $pCellAddress = null, $pStringTable = null, $pFlippedStringTable = null)
    {
        if (is_array($pStringTable) && is_array($pFlippedStringTable)) {
            // Cell
            $pCell = $pSheet->getCell($pCellAddress);
            $objWriter->startElement('c');
            $objWriter->writeAttribute('r', $pCellAddress);

            // Sheet styles
            if ($pCell->getXfIndex() != '') {
                $objWriter->writeAttribute('s', $pCell->getXfIndex());
            }

            // If cell value is supplied, write cell value
            $cellValue = $pCell->getValue();
            if (is_object($cellValue) || $cellValue !== '') {
                // Map type
                $mappedType = $pCell->getDataType();

                // Write data type depending on its type
                switch (strtolower($mappedType)) {
                    case 'inlinestr':    // Inline string
                    case 's':            // String
                    case 'b':            // Boolean
                        $objWriter->writeAttribute('t', $mappedType);
                        break;
                    case 'f':            // Formula
                        $calculatedValue = ($this->getParentWriter()->getPreCalculateFormulas()) ?
                            $pCell->getCalculatedValue() :
                            $cellValue;
                        if (is_string($calculatedValue)) {
                            $objWriter->writeAttribute('t', 'str');
                        }
                        break;
                    case 'e':            // Error
                        $objWriter->writeAttribute('t', $mappedType);
                }

                // Write data depending on its type
                switch (strtolower($mappedType)) {
                    case 'inlinestr':    // Inline string
                        if (! $cellValue instanceof PHPExcel_RichText) {
                            $objWriter->writeElement('t', PHPExcel_Shared_String::ControlCharacterPHP2OOXML( htmlspecialchars($cellValue) ) );
                        } else if ($cellValue instanceof PHPExcel_RichText) {
                            $objWriter->startElement('is');
                            $this->getParentWriter()->getWriterPart('stringtable')->writeRichText($objWriter, $cellValue);
                            $objWriter->endElement();
                        }

                        break;
                    case 's':            // String
                        if (! $cellValue instanceof PHPExcel_RichText) {
                            if (isset($pFlippedStringTable[$cellValue])) {
                                $objWriter->writeElement('v', $pFlippedStringTable[$cellValue]);
                            }
                        } else if ($cellValue instanceof PHPExcel_RichText) {
                            $objWriter->writeElement('v', $pFlippedStringTable[$cellValue->getHashCode()]);
                        }

                        break;
                    case 'f':            // Formula
                        $attributes = $pCell->getFormulaAttributes();
                        if ($attributes['t'] == 'array') {
                            $objWriter->startElement('f');
                            $objWriter->writeAttribute('t', 'array');
                            $objWriter->writeAttribute('ref', $pCellAddress);
                            $objWriter->writeAttribute('aca', '1');
                            $objWriter->writeAttribute('ca', '1');
                            $objWriter->text(substr($cellValue, 1));
                            $objWriter->endElement();
                        } else {
                            $objWriter->writeElement('f', substr($cellValue, 1));
                        }
                        if ($this->getParentWriter()->getOffice2003Compatibility() === false) {
                            if ($this->getParentWriter()->getPreCalculateFormulas()) {
//                                $calculatedValue = $pCell->getCalculatedValue();
                                if (!is_array($calculatedValue) && substr($calculatedValue, 0, 1) != '#') {
                                    $objWriter->writeElement('v', PHPExcel_Shared_String::FormatNumber($calculatedValue));
                                } else {
                                    $objWriter->writeElement('v', '0');
                                }
                            } else {
                                $objWriter->writeElement('v', '0');
                            }
                        }
                        break;
                    case 'n':            // Numeric
                        // force point as decimal separator in case current locale uses comma
                        $objWriter->writeElement('v', str_replace(',', '.', $cellValue));
                        break;
                    case 'b':            // Boolean
                        $objWriter->writeElement('v', ($cellValue ? '1' : '0'));
                        break;
                    case 'e':            // Error
                        if (substr($cellValue, 0, 1) == '=') {
                            $objWriter->writeElement('f', substr($cellValue, 1));
                            $objWriter->writeElement('v', substr($cellValue, 1));
                        } else {
                            $objWriter->writeElement('v', $cellValue);
                        }

                        break;
                }
            }

            $objWriter->endElement();
        } else {
            throw new PHPExcel_Writer_Exception("Invalid parameters passed.");
        }
    }

    /**
     * Write Drawings
     *
     * @param    PHPExcel_Shared_XMLWriter    $objWriter        XML Writer
     * @param    PHPExcel_Worksheet            $pSheet            Worksheet
     * @param    boolean                        $includeCharts    Flag indicating if we should include drawing details for charts
     * @throws    PHPExcel_Writer_Exception
     */
    private function _writeDrawings(PHPExcel_Shared_XMLWriter $objWriter = null, PHPExcel_Worksheet $pSheet = null, $includeCharts = FALSE)
    {
        $chartCount = ($includeCharts) ? $pSheet->getChartCollection()->count() : 0;
        // If sheet contains drawings, add the relationships
        if (($pSheet->getDrawingCollection()->count() > 0) ||
            ($chartCount > 0)) {
            $objWriter->startElement('drawing');
            $objWriter->writeAttribute('r:id', 'rId1');
            $objWriter->endElement();
        }
    }

    /**
     * Write LegacyDrawing
     *
     * @param    PHPExcel_Shared_XMLWriter        $objWriter        XML Writer
     * @param    PHPExcel_Worksheet                $pSheet            Worksheet
     * @throws    PHPExcel_Writer_Exception
     */
    private function _writeLegacyDrawing(PHPExcel_Shared_XMLWriter $objWriter = null, PHPExcel_Worksheet $pSheet = null)
    {
        // If sheet contains comments, add the relationships
        if (count($pSheet->getComments()) > 0) {
            $objWriter->startElement('legacyDrawing');
            $objWriter->writeAttribute('r:id', 'rId_comments_vml1');
            $objWriter->endElement();
        }
    }

    /**
     * Write LegacyDrawingHF
     *
     * @param    PHPExcel_Shared_XMLWriter        $objWriter        XML Writer
     * @param    PHPExcel_Worksheet                $pSheet            Worksheet
     * @throws    PHPExcel_Writer_Exception
     */
    private function _writeLegacyDrawingHF(PHPExcel_Shared_XMLWriter $objWriter = null, PHPExcel_Worksheet $pSheet = null)
    {
        // If sheet contains images, add the relationships
        if (count($pSheet->getHeaderFooter()->getImages()) > 0) {
            $objWriter->startElement('legacyDrawingHF');
            $objWriter->writeAttribute('r:id', 'rId_headerfooter_vml1');
            $objWriter->endElement();
        }
    }
}