diff --git a/src/xlsx/xlsxcell.cpp b/src/xlsx/xlsxcell.cpp
index 60b1d4e..bca708a 100644
--- a/src/xlsx/xlsxcell.cpp
+++ b/src/xlsx/xlsxcell.cpp
@@ -25,6 +25,7 @@
 #include "xlsxcell.h"
 #include "xlsxcell_p.h"
 #include "xlsxformat.h"
+#include "xlsxformat_p.h"
 #include "xlsxutility_p.h"
 #include "xlsxworksheet.h"
 #include "xlsxworkbook.h"
diff --git a/src/xlsx/xlsxformat.cpp b/src/xlsx/xlsxformat.cpp
index 6a4bd63..115ef55 100755
--- a/src/xlsx/xlsxformat.cpp
+++ b/src/xlsx/xlsxformat.cpp
@@ -30,8 +30,7 @@
 
 QT_BEGIN_NAMESPACE_XLSX
 
-FormatPrivate::FormatPrivate(Format *p) :
-    q_ptr(p)
+FormatPrivate::FormatPrivate()
 {
     dirty = true;
 
@@ -44,6 +43,23 @@ FormatPrivate::FormatPrivate(Format *p) :
     theme = 0;
 }
 
+FormatPrivate::FormatPrivate(const FormatPrivate &other)
+    : QSharedData(other)
+    , numberData(other.numberData), fontData(other.fontData), alignmentData(other.alignmentData)
+    , borderData(other.borderData), fillData(other.fillData), protectionData(other.protectionData)
+    , dirty(other.dirty), formatKey(other.formatKey)
+    , xf_index(other.xf_index), xf_indexValid(other.xf_indexValid)
+    , is_dxf_fomat(other.is_dxf_fomat), dxf_index(other.dxf_index), dxf_indexValid(other.dxf_indexValid)
+    , theme(other.theme)
+{
+
+}
+
+FormatPrivate::~FormatPrivate()
+{
+
+}
+
 /*!
  * \class Format
  * \inmodule QtXlsx
@@ -52,20 +68,38 @@ FormatPrivate::FormatPrivate(Format *p) :
 
 
 /*!
- * \internal
+ *  Creates a new format.
  */
 Format::Format() :
-    d_ptr(new FormatPrivate(this))
+    d(new FormatPrivate)
 {
 
 }
 
 /*!
- * \internal
+   Creates a new format with the same attributes as the \a other format.
+ */
+Format::Format(const Format &other)
+    :d(other.d)
+{
+
+}
+
+/*!
+   Assigns the \a other format to this format, and returns a
+   reference to this format.
+ */
+Format &Format::operator =(const Format &other)
+{
+    d = other.d;
+    return *this;
+}
+
+/*!
+ * Destroys this format.
  */
 Format::~Format()
 {
-    delete d_ptr;
 }
 
 /*!
@@ -73,7 +107,6 @@ Format::~Format()
  */
 int Format::numberFormatIndex() const
 {
-    Q_D(const Format);
     return d->numberData.formatIndex;
 }
 
@@ -84,7 +117,6 @@ int Format::numberFormatIndex() const
  */
 void Format::setNumberFormatIndex(int format)
 {
-    Q_D(Format);
     d->dirty = true;
     d->numberData.formatIndex = format;
     d->numberData._valid = true;
@@ -97,7 +129,6 @@ void Format::setNumberFormatIndex(int format)
  */
 QString Format::numberFormat() const
 {
-    Q_D(const Format);
     return d->numberData.formatString;
 }
 
@@ -107,7 +138,6 @@ QString Format::numberFormat() const
  */
 void Format::setNumberFormat(const QString &format)
 {
-    Q_D(Format);
     if (format.isEmpty())
         return;
     d->dirty = true;
@@ -120,7 +150,6 @@ void Format::setNumberFormat(const QString &format)
  */
 bool Format::isDateTimeFormat() const
 {
-    Q_D(const Format);
     if (d->numberData._valid && d->numberData.formatString.isEmpty()) {
         int idx = d->numberData.formatIndex;
         //Built in date time number index
@@ -141,7 +170,6 @@ bool Format::isDateTimeFormat() const
  */
 bool Format::numFmtIndexValid() const
 {
-    Q_D(const Format);
     return d->numberData._valid;
 }
 
@@ -150,7 +178,6 @@ bool Format::numFmtIndexValid() const
  */
 void Format::setNumFmt(int index, const QString &string)
 {
-    Q_D(Format);
     d->numberData.formatIndex = index;
     d->numberData.formatString = string;
     d->numberData._valid = true;
@@ -161,7 +188,6 @@ void Format::setNumFmt(int index, const QString &string)
  */
 int Format::fontSize() const
 {
-    Q_D(const Format);
     return d->fontData.size;
 }
 
@@ -170,7 +196,6 @@ int Format::fontSize() const
  */
 void Format::setFontSize(int size)
 {
-    Q_D(Format);
     d->fontData.size = size;
     d->fontData._dirty = true;
 }
@@ -180,7 +205,6 @@ void Format::setFontSize(int size)
  */
 bool Format::fontItalic() const
 {
-    Q_D(const Format);
     return d->fontData.italic;
 }
 
@@ -189,7 +213,6 @@ bool Format::fontItalic() const
  */
 void Format::setFontItalic(bool italic)
 {
-    Q_D(Format);
     d->fontData.italic = italic;
     d->fontData._dirty = true;
 }
@@ -199,7 +222,6 @@ void Format::setFontItalic(bool italic)
  */
 bool Format::fontStrikeOut() const
 {
-    Q_D(const Format);
     return d->fontData.strikeOut;
 }
 
@@ -208,7 +230,6 @@ bool Format::fontStrikeOut() const
  */
 void Format::setFontStrikeOut(bool strikeOut)
 {
-    Q_D(Format);
     d->fontData.strikeOut = strikeOut;
     d->fontData._dirty = true;
 }
@@ -218,7 +239,6 @@ void Format::setFontStrikeOut(bool strikeOut)
  */
 QColor Format::fontColor() const
 {
-    Q_D(const Format);
     if (!d->fontData.color.isValid() && !d->fontData.themeColor.isEmpty()) {
         //!Todo, get the real color from the theme{1}.xml file
         //The same is ture for border and fill colord
@@ -232,7 +252,6 @@ QColor Format::fontColor() const
  */
 void Format::setFontColor(const QColor &color)
 {
-    Q_D(Format);
     d->fontData.color = color;
     d->fontData._dirty = true;
 }
@@ -242,7 +261,6 @@ void Format::setFontColor(const QColor &color)
  */
 bool Format::fontBold() const
 {
-    Q_D(const Format);
     return d->fontData.bold;
 }
 
@@ -251,7 +269,6 @@ bool Format::fontBold() const
  */
 void Format::setFontBold(bool bold)
 {
-    Q_D(Format);
     d->fontData.bold = bold;
     d->fontData._dirty = true;
 }
@@ -261,7 +278,6 @@ void Format::setFontBold(bool bold)
  */
 Format::FontScript Format::fontScript() const
 {
-    Q_D(const Format);
     return d->fontData.scirpt;
 }
 
@@ -270,7 +286,6 @@ Format::FontScript Format::fontScript() const
  */
 void Format::setFontScript(FontScript script)
 {
-    Q_D(Format);
     d->fontData.scirpt = script;
     d->fontData._dirty = true;
 }
@@ -280,7 +295,6 @@ void Format::setFontScript(FontScript script)
  */
 Format::FontUnderline Format::fontUnderline() const
 {
-    Q_D(const Format);
     return d->fontData.underline;
 }
 
@@ -289,7 +303,6 @@ Format::FontUnderline Format::fontUnderline() const
  */
 void Format::setFontUnderline(FontUnderline underline)
 {
-    Q_D(Format);
     d->fontData.underline = underline;
     d->fontData._dirty = true;
 }
@@ -299,7 +312,6 @@ void Format::setFontUnderline(FontUnderline underline)
  */
 bool Format::fontOutline() const
 {
-    Q_D(const Format);
     return d->fontData.outline;
 }
 
@@ -308,7 +320,6 @@ bool Format::fontOutline() const
  */
 void Format::setFontOutline(bool outline)
 {
-    Q_D(Format);
     d->fontData.outline = outline;
     d->fontData._dirty = true;
 }
@@ -318,7 +329,6 @@ void Format::setFontOutline(bool outline)
  */
 QString Format::fontName() const
 {
-    Q_D(const Format);
     return d->fontData.name;
 }
 
@@ -327,7 +337,6 @@ QString Format::fontName() const
  */
 void Format::setFontName(const QString &name)
 {
-    Q_D(Format);
     d->fontData.name = name;
     d->fontData._dirty = true;
 }
@@ -337,7 +346,6 @@ void Format::setFontName(const QString &name)
  */
 bool Format::fontIndexValid() const
 {
-    Q_D(const Format);
     return d->fontData.indexValid();
 }
 
@@ -346,7 +354,6 @@ bool Format::fontIndexValid() const
  */
 int Format::fontIndex() const
 {
-    Q_D(const Format);
     return d->fontData.index();
 }
 
@@ -355,7 +362,6 @@ int Format::fontIndex() const
  */
 void Format::setFontIndex(int index)
 {
-    Q_D(Format);
     d->fontData.setIndex(index);
 }
 
@@ -364,7 +370,6 @@ void Format::setFontIndex(int index)
  */
 int Format::fontFamily() const
 {
-    Q_D(const Format);
     return d->fontData.family;
 }
 
@@ -373,7 +378,6 @@ int Format::fontFamily() const
  */
 bool Format::fontShadow() const
 {
-    Q_D(const Format);
     return d->fontData.shadow;
 }
 
@@ -382,7 +386,6 @@ bool Format::fontShadow() const
  */
 QString Format::fontScheme() const
 {
-    Q_D(const Format);
     return d->fontData.scheme;
 }
 
@@ -390,9 +393,8 @@ QString Format::fontScheme() const
  */
 QByteArray Format::fontKey() const
 {
-    Q_D(const Format);
     if (d->fontData._dirty)
-        const_cast<FormatPrivate*>(d)->dirty = true; //Make sure formatKey() will be re-generated.
+        d->dirty = true; //Make sure formatKey() will be re-generated.
     return d->fontData.key();
 }
 
@@ -401,7 +403,6 @@ QByteArray Format::fontKey() const
  */
 Format::HorizontalAlignment Format::horizontalAlignment() const
 {
-    Q_D(const Format);
     return d->alignmentData.alignH;
 }
 
@@ -410,7 +411,6 @@ Format::HorizontalAlignment Format::horizontalAlignment() const
  */
 void Format::setHorizontalAlignment(HorizontalAlignment align)
 {
-    Q_D(Format);
     if (d->alignmentData.indent &&(align != AlignHGeneral && align != AlignLeft &&
                               align != AlignRight && align != AlignHDistributed)) {
         d->alignmentData.indent = 0;
@@ -430,7 +430,6 @@ void Format::setHorizontalAlignment(HorizontalAlignment align)
  */
 Format::VerticalAlignment Format::verticalAlignment() const
 {
-    Q_D(const Format);
     return d->alignmentData.alignV;
 }
 
@@ -439,7 +438,6 @@ Format::VerticalAlignment Format::verticalAlignment() const
  */
 void Format::setVerticalAlignment(VerticalAlignment align)
 {
-    Q_D(Format);
     d->alignmentData.alignV = align;
     d->dirty = true;
 }
@@ -449,7 +447,6 @@ void Format::setVerticalAlignment(VerticalAlignment align)
  */
 bool Format::textWrap() const
 {
-    Q_D(const Format);
     return d->alignmentData.wrap;
 }
 
@@ -458,7 +455,6 @@ bool Format::textWrap() const
  */
 void Format::setTextWarp(bool wrap)
 {
-    Q_D(Format);
     if (wrap && d->alignmentData.shinkToFit)
         d->alignmentData.shinkToFit = false;
 
@@ -471,7 +467,6 @@ void Format::setTextWarp(bool wrap)
  */
 int Format::rotation() const
 {
-    Q_D(const Format);
     return d->alignmentData.rotation;
 }
 
@@ -480,7 +475,6 @@ int Format::rotation() const
  */
 void Format::setRotation(int rotation)
 {
-    Q_D(Format);
     d->alignmentData.rotation = rotation;
     d->dirty = true;
 }
@@ -490,7 +484,6 @@ void Format::setRotation(int rotation)
  */
 int Format::indent() const
 {
-    Q_D(const Format);
     return d->alignmentData.indent;
 }
 
@@ -499,7 +492,6 @@ int Format::indent() const
  */
 void Format::setIndent(int indent)
 {
-    Q_D(Format);
     if (indent && (d->alignmentData.alignH != AlignHGeneral
                    && d->alignmentData.alignH != AlignLeft
                    && d->alignmentData.alignH != AlignRight
@@ -515,7 +507,6 @@ void Format::setIndent(int indent)
  */
 bool Format::shrinkToFit() const
 {
-    Q_D(const Format);
     return d->alignmentData.shinkToFit;
 }
 
@@ -524,7 +515,6 @@ bool Format::shrinkToFit() const
  */
 void Format::setShrinkToFit(bool shink)
 {
-    Q_D(Format);
     if (shink && d->alignmentData.wrap)
         d->alignmentData.wrap = false;
     if (shink && (d->alignmentData.alignH == AlignHFill
@@ -542,7 +532,6 @@ void Format::setShrinkToFit(bool shink)
  */
 bool Format::alignmentChanged() const
 {
-    Q_D(const Format);
     return d->alignmentData.alignH != AlignHGeneral
             || d->alignmentData.alignV != AlignBottom
             || d->alignmentData.indent != 0
@@ -553,7 +542,6 @@ bool Format::alignmentChanged() const
 
 QString Format::horizontalAlignmentString() const
 {
-    Q_D(const Format);
     QString alignH;
     switch (d->alignmentData.alignH) {
     case Format::AlignLeft:
@@ -585,7 +573,6 @@ QString Format::horizontalAlignmentString() const
 
 QString Format::verticalAlignmentString() const
 {
-    Q_D(const Format);
     QString align;
     switch (d->alignmentData.alignV) {
     case AlignTop:
@@ -633,7 +620,6 @@ void Format::setBorderColor(const QColor &color)
  */
 Format::BorderStyle Format::leftBorderStyle() const
 {
-    Q_D(const Format);
     return d->borderData.left;
 }
 
@@ -642,7 +628,6 @@ Format::BorderStyle Format::leftBorderStyle() const
  */
 void Format::setLeftBorderStyle(BorderStyle style)
 {
-    Q_D(Format);
     d->borderData.left = style;
     d->borderData._dirty = true;
 }
@@ -652,149 +637,126 @@ void Format::setLeftBorderStyle(BorderStyle style)
  */
 QColor Format::leftBorderColor() const
 {
-    Q_D(const Format);
     return d->borderData.leftColor;
 }
 
 void Format::setLeftBorderColor(const QColor &color)
 {
-    Q_D(Format);
     d->borderData.leftColor = color;
     d->borderData._dirty = true;
 }
 
 Format::BorderStyle Format::rightBorderStyle() const
 {
-    Q_D(const Format);
     return d->borderData.right;
 }
 
 void Format::setRightBorderStyle(BorderStyle style)
 {
-    Q_D(Format);
     d->borderData.right = style;
     d->borderData._dirty = true;
 }
 
 QColor Format::rightBorderColor() const
 {
-    Q_D(const Format);
     return d->borderData.rightColor;
 }
 
 void Format::setRightBorderColor(const QColor &color)
 {
-    Q_D(Format);
     d->borderData.rightColor = color;
     d->borderData._dirty = true;
 }
 
 Format::BorderStyle Format::topBorderStyle() const
 {
-    Q_D(const Format);
     return d->borderData.top;
 }
 
 void Format::setTopBorderStyle(BorderStyle style)
 {
-    Q_D(Format);
     d->borderData.top = style;
     d->borderData._dirty = true;
 }
 
 QColor Format::topBorderColor() const
 {
-    Q_D(const Format);
     return d->borderData.topColor;
 }
 
 void Format::setTopBorderColor(const QColor &color)
 {
-    Q_D(Format);
     d->borderData.topColor = color;
     d->borderData._dirty = true;
 }
 
 Format::BorderStyle Format::bottomBorderStyle() const
 {
-    Q_D(const Format);
     return d->borderData.bottom;
 }
 
 void Format::setBottomBorderStyle(BorderStyle style)
 {
-    Q_D(Format);
     d->borderData.bottom = style;
     d->borderData._dirty = true;
 }
 
 QColor Format::bottomBorderColor() const
 {
-    Q_D(const Format);
     return d->borderData.bottomColor;
 }
 
 void Format::setBottomBorderColor(const QColor &color)
 {
-    Q_D(Format);
     d->borderData.bottomColor = color;
     d->borderData._dirty = true;
 }
 
 Format::BorderStyle Format::diagonalBorderStyle() const
 {
-    Q_D(const Format);
     return d->borderData.diagonal;
 }
 
 void Format::setDiagonalBorderStyle(BorderStyle style)
 {
-    Q_D(Format);
     d->borderData.diagonal = style;
     d->borderData._dirty = true;
 }
 
 Format::DiagonalBorderType Format::diagonalBorderType() const
 {
-    Q_D(const Format);
     return d->borderData.diagonalType;
 }
 
 void Format::setDiagonalBorderType(DiagonalBorderType style)
 {
-    Q_D(Format);
     d->borderData.diagonalType = style;
     d->borderData._dirty = true;
 }
 
 QColor Format::diagonalBorderColor() const
 {
-    Q_D(const Format);
     return d->borderData.diagonalColor;
 }
 
 void Format::setDiagonalBorderColor(const QColor &color)
 {
-    Q_D(Format);
     d->borderData.diagonalColor = color;
     d->borderData._dirty = true;
 }
 
 bool Format::borderIndexValid() const
 {
-    Q_D(const Format);
     return d->borderData.indexValid();
 }
 
 int Format::borderIndex() const
 {
-    Q_D(const Format);
     return d->borderData.index();
 }
 
 void Format::setBorderIndex(int index)
 {
-    Q_D(Format);
     d->borderData.setIndex(index);
 }
 
@@ -802,35 +764,30 @@ void Format::setBorderIndex(int index)
  */
 QByteArray Format::borderKey() const
 {
-    Q_D(const Format);
     if (d->borderData._dirty)
-        const_cast<FormatPrivate*>(d)->dirty = true; //Make sure formatKey() will be re-generated.
+        d->dirty = true; //Make sure formatKey() will be re-generated.
 
     return d->borderData.key();
 }
 
 Format::FillPattern Format::fillPattern() const
 {
-    Q_D(const Format);
     return d->fillData.pattern;
 }
 
 void Format::setFillPattern(FillPattern pattern)
 {
-    Q_D(Format);
     d->fillData.pattern = pattern;
     d->fillData._dirty = true;
 }
 
 QColor Format::patternForegroundColor() const
 {
-    Q_D(const Format);
     return d->fillData.fgColor;
 }
 
 void Format::setPatternForegroundColor(const QColor &color)
 {
-    Q_D(Format);
     if (color.isValid() && d->fillData.pattern == PatternNone)
         d->fillData.pattern = PatternSolid;
     d->fillData.fgColor = color;
@@ -839,13 +796,11 @@ void Format::setPatternForegroundColor(const QColor &color)
 
 QColor Format::patternBackgroundColor() const
 {
-    Q_D(const Format);
     return d->fillData.bgColor;
 }
 
 void Format::setPatternBackgroundColor(const QColor &color)
 {
-    Q_D(Format);
     if (color.isValid() && d->fillData.pattern == PatternNone)
         d->fillData.pattern = PatternSolid;
     d->fillData.bgColor = color;
@@ -854,19 +809,16 @@ void Format::setPatternBackgroundColor(const QColor &color)
 
 bool Format::fillIndexValid() const
 {
-    Q_D(const Format);
     return d->fillData.indexValid();
 }
 
 int Format::fillIndex() const
 {
-    Q_D(const Format);
     return d->fillData.index();
 }
 
 void Format::setFillIndex(int index)
 {
-    Q_D(Format);
     d->fillData.setIndex(index);
 }
 
@@ -874,42 +826,36 @@ void Format::setFillIndex(int index)
  */
 QByteArray Format::fillKey() const
 {
-    Q_D(const Format);
     if (d->fillData._dirty)
-        const_cast<FormatPrivate*>(d)->dirty = true; //Make sure formatKey() will be re-generated.
+        d->dirty = true; //Make sure formatKey() will be re-generated.
 
     return d->fillData.key();
 }
 
 bool Format::hidden() const
 {
-    Q_D(const Format);
     return d->protectionData.hidden;
 }
 
 void Format::setHidden(bool hidden)
 {
-    Q_D(Format);
     d->protectionData.hidden = hidden;
     d->dirty = true;
 }
 
 bool Format::locked() const
 {
-    Q_D(const Format);
     return d->protectionData.locked;
 }
 
 void Format::setLocked(bool locked)
 {
-    Q_D(Format);
     d->protectionData.locked = locked;
     d->dirty = true;
 }
 
 QByteArray Format::formatKey() const
 {
-    Q_D(const Format);
     if (d->dirty || d->fontData._dirty || d->borderData._dirty || d->fillData._dirty) {
         QByteArray key;
         QDataStream stream(&key, QIODevice::WriteOnly);
@@ -918,10 +864,10 @@ QByteArray Format::formatKey() const
             <<d->alignmentData.alignH<<d->alignmentData.alignV<<d->alignmentData.indent
            <<d->alignmentData.rotation<<d->alignmentData.shinkToFit<<d->alignmentData.wrap
           <<d->protectionData.hidden<<d->protectionData.locked;
-        const_cast<FormatPrivate*>(d)->formatKey = key;
-        const_cast<FormatPrivate*>(d)->dirty = false;
-        const_cast<FormatPrivate*>(d)->xf_indexValid = false;
-        const_cast<FormatPrivate*>(d)->dxf_indexValid = false;
+        d->formatKey = key;
+        d->dirty = false;
+        d->xf_indexValid = false;
+        d->dxf_indexValid = false;
     }
 
     return d->formatKey;
@@ -929,39 +875,33 @@ QByteArray Format::formatKey() const
 
 void Format::setXfIndex(int index)
 {
-    Q_D(Format);
     d->xf_index = index;
     d->xf_indexValid = true;
 }
 
 int Format::xfIndex() const
 {
-    Q_D(const Format);
     return d->xf_index;
 }
 
 bool Format::xfIndexValid() const
 {
-    Q_D(const Format);
     return !d->dirty && d->xf_indexValid;
 }
 
 void Format::setDxfIndex(int index)
 {
-    Q_D(Format);
     d->dxf_index = index;
     d->dxf_indexValid = true;
 }
 
 int Format::dxfIndex() const
 {
-    Q_D(const Format);
     return d->dxf_index;
 }
 
 bool Format::dxfIndexValid() const
 {
-    Q_D(const Format);
     return !d->dirty && d->dxf_indexValid;
 }
 
@@ -977,13 +917,11 @@ bool Format::operator !=(const Format &format) const
 
 bool Format::isDxfFormat() const
 {
-    Q_D(const Format);
     return d->is_dxf_fomat;
 }
 
 int Format::theme() const
 {
-    Q_D(const Format);
     return d->theme;
 }
 
diff --git a/src/xlsx/xlsxformat.h b/src/xlsx/xlsxformat.h
index 2f214e8..7b192ef 100755
--- a/src/xlsx/xlsxformat.h
+++ b/src/xlsx/xlsxformat.h
@@ -30,6 +30,7 @@
 #include <QColor>
 #include <QByteArray>
 #include <QList>
+#include <QSharedDataPointer>
 
 class FormatTest;
 
@@ -44,7 +45,6 @@ class SharedStrings;
 class FormatPrivate;
 class Q_XLSX_EXPORT Format
 {
-    Q_DECLARE_PRIVATE(Format)
 public:
     enum FontScript
     {
@@ -132,6 +132,9 @@ public:
         PatternLightGrid
     };
 
+    Format();
+    Format(const Format &other);
+    Format &operator=(const Format &rhs);
     ~Format();
 
     int numberFormatIndex() const;
@@ -220,8 +223,6 @@ private:
     friend class SharedStrings;
     friend class ::FormatTest;
 
-    Format();
-
     bool numFmtIndexValid() const;
     void setNumFmt(int index, const QString &string);
 
@@ -258,7 +259,7 @@ private:
 
     int theme() const;
 
-    FormatPrivate * const d_ptr;
+    QSharedDataPointer<FormatPrivate> d;
 };
 
 QT_END_NAMESPACE_XLSX
diff --git a/src/xlsx/xlsxformat_p.h b/src/xlsx/xlsxformat_p.h
index c363557..8245ca6 100644
--- a/src/xlsx/xlsxformat_p.h
+++ b/src/xlsx/xlsxformat_p.h
@@ -25,6 +25,7 @@
 #ifndef XLSXFORMAT_P_H
 #define XLSXFORMAT_P_H
 #include "xlsxformat.h"
+#include <QSharedData>
 
 namespace QXlsx {
 
@@ -250,11 +251,12 @@ struct XlsxFormatProtectionData {
     bool hidden;
 };
 
-class FormatPrivate
+class FormatPrivate : public QSharedData
 {
-    Q_DECLARE_PUBLIC(Format)
 public:
-    FormatPrivate(Format *p);
+    FormatPrivate();
+    FormatPrivate(const FormatPrivate &other);
+    ~FormatPrivate();
 
     XlsxFormatNumberData numberData;
     XlsxFormatFontData fontData;
@@ -263,21 +265,17 @@ public:
     XlsxFormatFillData fillData;
     XlsxFormatProtectionData protectionData;
 
-    bool dirty; //The key re-generation is need.
-    QByteArray formatKey;
+    mutable bool dirty; //The key re-generation is need.
+    mutable QByteArray formatKey;
 
-    static QList<Format *> s_xfFormats;
     int xf_index;
-    bool xf_indexValid;
+    mutable bool xf_indexValid;
 
-    static QList<Format *> s_dxfFormats;
     bool is_dxf_fomat;
     int dxf_index;
-    bool dxf_indexValid;
+    mutable bool dxf_indexValid;
 
     int theme;
-
-    Format *q_ptr;
 };
 
 }
diff --git a/src/xlsx/xlsxpackage.cpp b/src/xlsx/xlsxpackage.cpp
index 7b144e2..c750625 100644
--- a/src/xlsx/xlsxpackage.cpp
+++ b/src/xlsx/xlsxpackage.cpp
@@ -38,6 +38,7 @@
 #include "xlsxdrawing_p.h"
 #include "xlsxzipreader_p.h"
 #include "xlsxdocument.h"
+#include "xlsxformat_p.h"
 #include <QBuffer>
 #include <QDebug>
 #include <QDir>
diff --git a/src/xlsx/xlsxrichstring.cpp b/src/xlsx/xlsxrichstring.cpp
index cd98e09..c13811c 100644
--- a/src/xlsx/xlsxrichstring.cpp
+++ b/src/xlsx/xlsxrichstring.cpp
@@ -23,6 +23,7 @@
 **
 ****************************************************************************/
 #include "xlsxrichstring_p.h"
+#include "xlsxformat_p.h"
 
 QT_BEGIN_NAMESPACE_XLSX
 
diff --git a/src/xlsx/xlsxsharedstrings.cpp b/src/xlsx/xlsxsharedstrings.cpp
index c08025e..7eec844 100755
--- a/src/xlsx/xlsxsharedstrings.cpp
+++ b/src/xlsx/xlsxsharedstrings.cpp
@@ -130,7 +130,7 @@ void SharedStrings::writeRichStringPart_rPr(XmlStreamWriter &writer, Format *for
     if (!format)
         return;
 
-    XlsxFormatFontData *font = &format->d_ptr->fontData;
+    XlsxFormatFontData *font = &format->d->fontData;
 
     if (font->bold)
         writer.writeEmptyElement(QStringLiteral("b"));
@@ -303,9 +303,9 @@ Format *SharedStrings::readRichStringPart_rPr(XmlStreamReader &reader, RichStrin
             if (reader.name() == QLatin1String("rFont")) {
                 format->setFontName(attributes.value(QLatin1String("val")).toString());
             } else if (reader.name() == QLatin1String("charset")) {
-                format->d_ptr->fontData.charset = attributes.value(QLatin1String("val")).toString().toInt();
+                format->d->fontData.charset = attributes.value(QLatin1String("val")).toString().toInt();
             }  else if (reader.name() == QLatin1String("family")) {
-                format->d_ptr->fontData.family = attributes.value(QLatin1String("val")).toString().toInt();
+                format->d->fontData.family = attributes.value(QLatin1String("val")).toString().toInt();
             }  else if (reader.name() == QLatin1String("b")) {
                 format->setFontBold(true);
             }  else if (reader.name() == QLatin1String("i")) {
@@ -315,11 +315,11 @@ Format *SharedStrings::readRichStringPart_rPr(XmlStreamReader &reader, RichStrin
             }  else if (reader.name() == QLatin1String("outline")) {
                 format->setFontOutline(true);
             }  else if (reader.name() == QLatin1String("shadow")) {
-                format->d_ptr->fontData.shadow = true;
+                format->d->fontData.shadow = true;
             }  else if (reader.name() == QLatin1String("condense")) {
-                format->d_ptr->fontData.condense = attributes.value(QLatin1String("val")).toString().toInt();
+                format->d->fontData.condense = attributes.value(QLatin1String("val")).toString().toInt();
             }  else if (reader.name() == QLatin1String("extend")) {
-                format->d_ptr->fontData.extend = attributes.value(QLatin1String("val")).toString().toInt();
+                format->d->fontData.extend = attributes.value(QLatin1String("val")).toString().toInt();
             }  else if (reader.name() == QLatin1String("color")) {
                 if (attributes.hasAttribute(QLatin1String("rgb"))) {
                     QString colorString = attributes.value(QLatin1String("rgb")).toString();
@@ -329,7 +329,7 @@ Format *SharedStrings::readRichStringPart_rPr(XmlStreamReader &reader, RichStrin
                 } else if (attributes.hasAttribute(QLatin1String("theme"))) {
                     QString theme = attributes.value(QLatin1String("theme")).toString();
                     QString tint = attributes.value(QLatin1String("tint")).toString();
-                    format->d_ptr->fontData.themeColor = theme + QLatin1Char(':') + tint;
+                    format->d->fontData.themeColor = theme + QLatin1Char(':') + tint;
                 }
             }  else if (reader.name() == QLatin1String("sz")) {
                 format->setFontSize(attributes.value(QLatin1String("val")).toString().toInt());
@@ -350,7 +350,7 @@ Format *SharedStrings::readRichStringPart_rPr(XmlStreamReader &reader, RichStrin
                 else if (value == QLatin1String("subscript"))
                     format->setFontScript(Format::FontScriptSub);
             }  else if (reader.name() == QLatin1String("scheme")) {
-                format->d_ptr->fontData.scheme = attributes.value(QLatin1String("val")).toString();
+                format->d->fontData.scheme = attributes.value(QLatin1String("val")).toString();
             }
         }
     }
diff --git a/src/xlsx/xlsxstyles.cpp b/src/xlsx/xlsxstyles.cpp
index c6f73e7..95931c3 100755
--- a/src/xlsx/xlsxstyles.cpp
+++ b/src/xlsx/xlsxstyles.cpp
@@ -138,7 +138,7 @@ void Styles::addFormat(Format *format, bool force)
             //Assign a new fmt Id.
             format->setNumFmt(m_nextCustomNumFmtId, str);
 
-            QSharedPointer<XlsxFormatNumberData> fmt(new XlsxFormatNumberData(format->d_func()->numberData));
+            QSharedPointer<XlsxFormatNumberData> fmt(new XlsxFormatNumberData(format->d->numberData));
             m_customNumFmtIdMap.insert(m_nextCustomNumFmtId, fmt);
             m_customNumFmtsHash.insert(str, fmt);
 
@@ -149,7 +149,7 @@ void Styles::addFormat(Format *format, bool force)
     //Font
     if (!format->fontIndexValid()) {
         if (!m_fontsHash.contains(format->fontKey())) {
-            QSharedPointer<XlsxFormatFontData> font = QSharedPointer<XlsxFormatFontData>(new XlsxFormatFontData(format->d_func()->fontData));
+            QSharedPointer<XlsxFormatFontData> font = QSharedPointer<XlsxFormatFontData>(new XlsxFormatFontData(format->d->fontData));
             font->setIndex(m_fontsList.size()); //Assign proper index
             m_fontsList.append(font);
             m_fontsHash[font->key()] = font;
@@ -160,7 +160,7 @@ void Styles::addFormat(Format *format, bool force)
     //Fill
     if (!format->fillIndexValid()) {
         if (!m_fillsHash.contains(format->fillKey())) {
-            QSharedPointer<XlsxFormatFillData> fill = QSharedPointer<XlsxFormatFillData>(new XlsxFormatFillData(format->d_func()->fillData));
+            QSharedPointer<XlsxFormatFillData> fill = QSharedPointer<XlsxFormatFillData>(new XlsxFormatFillData(format->d->fillData));
             fill->setIndex(m_fillsList.size()); //Assign proper index
             m_fillsList.append(fill);
             m_fillsHash[fill->key()] = fill;
@@ -171,7 +171,7 @@ void Styles::addFormat(Format *format, bool force)
     //Border
     if (!format->borderIndexValid()) {
         if (!m_bordersHash.contains(format->borderKey())) {
-            QSharedPointer<XlsxFormatBorderData> border = QSharedPointer<XlsxFormatBorderData>(new XlsxFormatBorderData(format->d_func()->borderData));
+            QSharedPointer<XlsxFormatBorderData> border = QSharedPointer<XlsxFormatBorderData>(new XlsxFormatBorderData(format->d->borderData));
             border->setIndex(m_bordersList.size()); //Assign proper index
             m_bordersList.append(border);
             m_bordersHash[border->key()] = border;
@@ -897,7 +897,7 @@ bool Styles::readCellXfs(XmlStreamReader &reader)
             if (!m_customNumFmtIdMap.contains(numFmtIndex))
                 format->setNumberFormatIndex(numFmtIndex);
             else
-                format->d_func()->numberData = *m_customNumFmtIdMap[numFmtIndex];
+                format->d->numberData = *m_customNumFmtIdMap[numFmtIndex];
         }
 
         if (xfAttrs.hasAttribute(QLatin1String("applyFont"))) {
@@ -905,7 +905,7 @@ bool Styles::readCellXfs(XmlStreamReader &reader)
             if (fontIndex >= m_fontsList.size()) {
                 qDebug("Error read styles.xml, cellXfs fontId");
             } else {
-                format->d_func()->fontData = *m_fontsList[fontIndex];
+                format->d->fontData = *m_fontsList[fontIndex];
             }
         }
 
@@ -914,7 +914,7 @@ bool Styles::readCellXfs(XmlStreamReader &reader)
             if (id >= m_fillsList.size()) {
                 qDebug("Error read styles.xml, cellXfs fillId");
             } else {
-                format->d_func()->fillData = *m_fillsList[id];
+                format->d->fillData = *m_fillsList[id];
             }
         }
 
@@ -923,7 +923,7 @@ bool Styles::readCellXfs(XmlStreamReader &reader)
             if (id >= m_bordersList.size()) {
                 qDebug("Error read styles.xml, cellXfs borderId");
             } else {
-                format->d_func()->borderData = *m_bordersList[id];
+                format->d->borderData = *m_bordersList[id];
             }
         }
 
diff --git a/src/xlsx/xlsxworkbook.cpp b/src/xlsx/xlsxworkbook.cpp
index d336731..e889da4 100755
--- a/src/xlsx/xlsxworkbook.cpp
+++ b/src/xlsx/xlsxworkbook.cpp
@@ -32,6 +32,7 @@
 #include "xlsxxmlwriter_p.h"
 #include "xlsxxmlreader_p.h"
 #include "xlsxworksheet_p.h"
+#include "xlsxformat_p.h"
 
 #include <QFile>
 #include <QBuffer>
diff --git a/src/xlsx/xlsxworksheet.cpp b/src/xlsx/xlsxworksheet.cpp
index 0bc005f..cf74244 100755
--- a/src/xlsx/xlsxworksheet.cpp
+++ b/src/xlsx/xlsxworksheet.cpp
@@ -27,6 +27,7 @@
 #include "xlsxworksheet_p.h"
 #include "xlsxworkbook.h"
 #include "xlsxformat.h"
+#include "xlsxformat_p.h"
 #include "xlsxutility_p.h"
 #include "xlsxsharedstrings_p.h"
 #include "xlsxxmlwriter_p.h"