basebmp/source/intconversion.hxx

   1 /* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
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  17  *   the License at http://www.apache.org/licenses/LICENSE-2.0 .
  18  */
  19
  20 #ifndef INCLUDED_BASEBMP_INTCONVERSION_HXX
  21 #define INCLUDED_BASEBMP_INTCONVERSION_HXX
  22
  23 #include <vigra/rgbvalue.hxx>
  24 #include <functional>
  25
  26 namespace basebmp
  27 {
  28     // metafunctions to retrieve correct POD from/to basebmp::Color
  29     //------------------------------------------------------------------------
  30
  31     /// type-safe conversion from RgbValue to packed int32
  32     template< class RgbVal > struct UInt32FromRgbValue
  33     {
  34         sal_uInt32 operator()( RgbVal const& c ) const
  35         {
  36             return (c[0] << 16) | (c[1] << 8) | c[2];
  37         }
  38     };
  39
  40     /// type-safe conversion from packed int32 to RgbValue
  41     template< class RgbVal > struct RgbValueFromUInt32
  42     {
  43         RgbVal operator()( sal_uInt32 c ) const
  44         {
  45             return RgbVal((c >> 16) & 0xFF,
  46                           (c >> 8) & 0xFF,
  47                           c & 0xFF);
  48         }
  49     };
  50
  51     //Current c++0x draft (apparently) has std::identity, but not operator()
  52     template<typename T> struct SGI_identity : public std::unary_function<T,T>
  53     {
  54         T& operator()(T& x) const { return x; }
  55         const T& operator()(const T& x) const { return x; }
  56     };
  57
  58     /// Get converter from given data type to sal_uInt32
  59     template< typename DataType > struct uInt32Converter
  60     {
  61         typedef SGI_identity<DataType> to;
  62         typedef SGI_identity<DataType> from;
  63     };
  64     template< unsigned int RedIndex,
  65               unsigned int GreenIndex,
  66               unsigned int BlueIndex > struct uInt32Converter<
  67                   vigra::RGBValue< sal_uInt8,
  68                                    RedIndex,
  69                                    GreenIndex,
  70                                    BlueIndex > >
  71     {
  72         typedef UInt32FromRgbValue<
  73             vigra::RGBValue< sal_uInt8,
  74                              RedIndex,
  75                              GreenIndex,
  76                              BlueIndex > >
  77             to;
  78         typedef RgbValueFromUInt32<
  79             vigra::RGBValue< sal_uInt8,
  80                              RedIndex,
  81                              GreenIndex,
  82                              BlueIndex > >
  83             from;
  84     };
  85 }
  86
  87 #endif /* INCLUDED_BASEBMP_INTCONVERSION_HXX */
  88
  89 /* vim:set shiftwidth=4 softtabstop=4 expandtab: */