ceph/src/boost/boost/gil/io/conversion_policies.hpp

   1 //
   2 // Copyright 2007-2008 Christian Henning, Andreas Pokorny
   3 //
   4 // Distributed under the Boost Software License, Version 1.0
   5 // See accompanying file LICENSE_1_0.txt or copy at
   6 // http://www.boost.org/LICENSE_1_0.txt
   7 //
   8 #ifndef BOOST_GIL_IO_CONVERSION_POLICIES_HPP
   9 #define BOOST_GIL_IO_CONVERSION_POLICIES_HPP
  10
  11 #include <boost/gil/image_view_factory.hpp>
  12 #include <boost/gil/detail/mp11.hpp>
  13 #include <boost/gil/io/error.hpp>
  14
  15 #include <algorithm>
  16 #include <iterator>
  17 #include <type_traits>
  18
  19 namespace boost{ namespace gil { namespace detail {
  20
  21 struct read_and_no_convert
  22 {
  23 public:
  24     using color_converter_type = void *;
  25
  26     template <typename InIterator, typename OutIterator>
  27     void read(
  28         InIterator const& /*begin*/, InIterator const& /*end*/ , OutIterator /*out*/,
  29         typename std::enable_if
  30         <
  31             mp11::mp_not
  32             <
  33                 pixels_are_compatible
  34                 <
  35                     typename std::iterator_traits<InIterator>::value_type,
  36                     typename std::iterator_traits<OutIterator>::value_type
  37                 >
  38             >::value
  39         >::type* /*dummy*/ = nullptr)
  40     {
  41         io_error("Data cannot be copied because the pixels are incompatible.");
  42     }
  43
  44     template <typename InIterator, typename OutIterator>
  45     void read(InIterator const& begin, InIterator const& end, OutIterator out,
  46         typename std::enable_if
  47         <
  48             pixels_are_compatible
  49             <
  50                 typename std::iterator_traits<InIterator>::value_type,
  51                 typename std::iterator_traits<OutIterator>::value_type
  52             >::value
  53         >::type* /*dummy*/ = nullptr)
  54     {
  55         std::copy(begin, end, out);
  56     }
  57 };
  58
  59 template<typename CC>
  60 struct read_and_convert
  61 {
  62 public:
  63     using color_converter_type = default_color_converter;
  64     CC _cc;
  65
  66     read_and_convert()
  67     {}
  68
  69     read_and_convert( const color_converter_type& cc )
  70     : _cc( cc )
  71     {}
  72
  73     template< typename InIterator
  74             , typename OutIterator
  75             >
  76     void read( const InIterator& begin
  77              , const InIterator& end
  78              , OutIterator       out
  79              )
  80     {
  81         using deref_t = color_convert_deref_fn<typename std::iterator_traits<InIterator>::reference
  82                                       , typename std::iterator_traits<OutIterator>::value_type //reference?
  83                                       , CC
  84                                       >;
  85
  86         std::transform( begin
  87                       , end
  88                       , out
  89                       , deref_t( _cc )
  90                       );
  91     }
  92 };
  93
  94 /// is_read_only metafunction
  95 /// \brief Determines if reader type is read only ( no conversion ).
  96 template< typename Conversion_Policy >
  97 struct is_read_only : std::false_type {};
  98
  99 template<>
 100 struct is_read_only<detail::read_and_no_convert> : std::true_type {};
 101
 102 } // namespace detail
 103 } // namespace gil
 104 } // namespace boost
 105
 106 #endif