basebmp/inc/accessortraits.hxx

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  19
  20 #ifndef INCLUDED_BASEBMP_INC_ACCESSORTRAITS_HXX
  21 #define INCLUDED_BASEBMP_INC_ACCESSORTRAITS_HXX
  22
  23 #include <accessorfunctors.hxx>
  24 #include <accessoradapters.hxx>
  25 #include <metafunctions.hxx>
  26
  27 #include <o3tl/compat_functional.hxx>
  28
  29 #include <functional>
  30
  31 namespace basebmp
  32 {
  33
  34 struct FastMask;
  35 struct NoFastMask;
  36
  37 /// Metafunction to select output mask functor from iterator and mask value type
  38 template< typename T, typename M, bool polarity, typename DUMMY > struct outputMaskFunctorSelector : public
  39     ifBothScalarIntegral< T, M,
  40                           IntegerOutputMaskFunctor< T, M, polarity >,
  41                           GenericOutputMaskFunctor< T, M, polarity > >
  42 {
  43 };
  44 template< typename T, typename M, bool polarity > struct outputMaskFunctorSelector< T, M, polarity, FastMask > : public
  45     ifBothScalarIntegral< T, M,
  46                           FastIntegerOutputMaskFunctor< T, M, polarity >,
  47                           GenericOutputMaskFunctor< T, M, polarity > >
  48 {
  49 };
  50
  51 /** Metafunction providing a point of configuration for iterators
  52     capable of employing the fast output mask functor.
  53
  54     Specialize this metafunction for your case, and pass FastMask to
  55     the outputMaskFunctorSelector.
  56  */
  57 template< class Accessor,
  58           class MaskAccessor,
  59           class Iterator,
  60           class MaskIterator,
  61           bool  polarity > struct maskedAccessorSelector
  62 {
  63     typedef TernarySetterFunctionAccessorAdapter<
  64         Accessor,
  65         MaskAccessor,
  66         typename outputMaskFunctorSelector<
  67             typename Accessor::value_type,
  68             typename MaskAccessor::value_type,
  69             polarity,
  70             NoFastMask > ::type >
  71         type;
  72 };
  73
  74
  75
  76 /** Traits template for Accessor
  77
  78     Provides wrapped types for color lookup, raw pixel access, xor and
  79     mask accessors.
  80  */
  81 template< class Accessor > struct AccessorTraits
  82 {
  83     /// value type of described accessor
  84     typedef typename Accessor::value_type           value_type;
  85
  86     /// Retrieve stand-alone color lookup function for given Accessor type
  87     typedef o3tl::project2nd< Accessor, value_type > color_lookup;
  88
  89     /// Retrieve raw pixel data accessor for given Accessor type
  90     typedef Accessor                                raw_accessor;
  91
  92     /// Retrieve wrapped accessor for XOR setter access
  93     typedef BinarySetterFunctionAccessorAdapter<
  94         Accessor,
  95         XorFunctor< value_type > >                  xor_accessor;
  96
  97     /** Retrieve masked accessor for given types
  98
  99         A masked accessor works like a filter, where the mask gates
 100         the accessor's setter methods (if the mask contains a 0 at a
 101         given iterator position, the original value is
 102         preserved. Otherwise, the new value gets set).
 103
 104         @attention be careful when retrieving a masked accessor for a
 105         set of types, and using it for a different one - there are
 106         partial specializations that take an optimized functor for
 107         certain mask accessors.
 108      */
 109     template< class MaskAccessor,
 110               class Iterator,
 111               class MaskIterator,
 112               bool  polarity > struct               masked_accessor :
 113         public maskedAccessorSelector< Accessor,
 114                                        MaskAccessor,
 115                                        Iterator,
 116                                        MaskIterator,
 117                                        polarity >
 118     {};
 119
 120 };
 121
 122 } // namespace basebmp
 123
 124 #endif /* INCLUDED_BASEBMP_INC_ACCESSORTRAITS_HXX */
 125
 126 /* vim:set shiftwidth=4 softtabstop=4 expandtab: */