ceph/src/boost/boost/gil/utilities.hpp

   1 //
   2 // Copyright 2005-2007 Adobe Systems Incorporated
   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_UTILITIES_HPP
   9 #define BOOST_GIL_UTILITIES_HPP
  10
  11 #include <boost/gil/detail/mp11.hpp>
  12
  13 #include <boost/config.hpp>
  14
  15 #if defined(BOOST_CLANG)
  16 #pragma clang diagnostic push
  17 #pragma clang diagnostic ignored "-Wconversion"
  18 #endif
  19
  20 #if defined(BOOST_GCC) && (BOOST_GCC >= 40900)
  21 #pragma GCC diagnostic push
  22 #pragma GCC diagnostic ignored "-Wconversion"
  23 #endif
  24
  25 #include <boost/iterator/iterator_adaptor.hpp>
  26 #include <boost/iterator/iterator_facade.hpp>
  27
  28 #if defined(BOOST_CLANG)
  29 #pragma clang diagnostic pop
  30 #endif
  31
  32 #if defined(BOOST_GCC) && (BOOST_GCC >= 40900)
  33 #pragma GCC diagnostic pop
  34 #endif
  35
  36 #include <algorithm>
  37 #include <cmath>
  38 #include <cstddef>
  39 #include <functional>
  40 #include <iterator>
  41 #include <utility>
  42 #include <type_traits>
  43
  44 namespace boost { namespace gil {
  45
  46 /// Various utilities not specific to the image library.
  47 /// Some are non-standard STL extensions or generic iterator adaptors
  48
  49 ////////////////////////////////////////////////////////////////////////////////
  50 ///  Rounding of real numbers / points to integers / integer points
  51 ////////////////////////////////////////////////////////////////////////////////
  52
  53 inline std::ptrdiff_t iround(float x)
  54 {
  55     return static_cast<std::ptrdiff_t>(x + (x < 0.0f ? -0.5f : 0.5f));
  56 }
  57
  58 inline std::ptrdiff_t iround(double x)
  59 {
  60     return static_cast<std::ptrdiff_t>(x + (x < 0.0 ? -0.5 : 0.5));
  61 }
  62
  63 inline std::ptrdiff_t ifloor(float x)
  64 {
  65     return static_cast<std::ptrdiff_t>(std::floor(x));
  66 }
  67
  68 inline std::ptrdiff_t ifloor(double x)
  69 {
  70     return static_cast<std::ptrdiff_t>(std::floor(x));
  71 }
  72
  73 inline std::ptrdiff_t iceil(float x)
  74 {
  75     return static_cast<std::ptrdiff_t>(std::ceil(x));
  76 }
  77
  78 inline std::ptrdiff_t iceil(double x)
  79 {
  80     return static_cast<std::ptrdiff_t>(std::ceil(x));
  81 }
  82
  83 ////////////////////////////////////////////////////////////////////////////////
  84 ///  computing size with alignment
  85 ////////////////////////////////////////////////////////////////////////////////
  86
  87 template <typename T>
  88 inline T align(T val, std::size_t alignment)
  89 {
  90     return val+(alignment - val%alignment)%alignment;
  91 }
  92
  93 /// \brief Helper base class for pixel dereference adaptors.
  94 /// \ingroup PixelDereferenceAdaptorModel
  95 ///
  96 template
  97 <
  98     typename ConstT,
  99     typename Value,
 100     typename Reference,
 101     typename ConstReference,
 102     typename ArgType,
 103     typename ResultType,
 104     bool IsMutable
 105 >
 106 struct deref_base
 107 {
 108     using argument_type = ArgType;
 109     using result_type = ResultType;
 110     using const_t = ConstT;
 111     using value_type = Value;
 112     using reference = Reference;
 113     using const_reference = ConstReference;
 114     static constexpr bool is_mutable = IsMutable;
 115 };
 116
 117 /// \brief Composes two dereference function objects. Similar to std::unary_compose but needs to pull some aliases from the component types.  Models: PixelDereferenceAdaptorConcept
 118 /// \ingroup PixelDereferenceAdaptorModel
 119 ///
 120 template <typename D1, typename D2>
 121 class deref_compose : public deref_base
 122 <
 123     deref_compose<typename D1::const_t, typename D2::const_t>,
 124     typename D1::value_type,
 125     typename D1::reference,
 126     typename D1::const_reference,
 127     typename D2::argument_type,
 128     typename D1::result_type,
 129     D1::is_mutable && D2::is_mutable
 130 >
 131 {
 132 public:
 133     D1 _fn1;
 134     D2 _fn2;
 135
 136     using argument_type = typename D2::argument_type;
 137     using result_type = typename D1::result_type;
 138
 139     deref_compose() = default;
 140     deref_compose(const D1& x, const D2& y) : _fn1(x), _fn2(y) {}
 141     deref_compose(const deref_compose& dc)  : _fn1(dc._fn1), _fn2(dc._fn2) {}
 142
 143     template <typename _D1, typename _D2>
 144     deref_compose(const deref_compose<_D1,_D2>& dc)
 145         : _fn1(dc._fn1), _fn2(dc._fn2)
 146     {}
 147
 148     result_type operator()(argument_type x) const { return _fn1(_fn2(x)); }
 149     result_type operator()(argument_type x)       { return _fn1(_fn2(x)); }
 150 };
 151
 152 // reinterpret_cast is implementation-defined. Static cast is not.
 153 template <typename OutPtr, typename In>
 154 BOOST_FORCEINLINE
 155 OutPtr gil_reinterpret_cast(In* p)
 156 {
 157     return static_cast<OutPtr>(static_cast<void*>(p));
 158 }
 159
 160 template <typename OutPtr, typename In> BOOST_FORCEINLINE
 161 const OutPtr gil_reinterpret_cast_c(const In* p)
 162 {
 163     return static_cast<const OutPtr>(static_cast<const void*>(p));
 164 }
 165
 166 namespace detail {
 167
 168 ////////////////////////////////////////////////////////////////////////////////
 169 ///  \brief copy_n taken from SGI STL.
 170 ////////////////////////////////////////////////////////////////////////////////
 171
 172 template <class InputIter, class Size, class OutputIter>
 173 std::pair<InputIter, OutputIter> _copy_n(InputIter first, Size count,
 174     OutputIter result, std::input_iterator_tag)
 175 {
 176    for ( ; count > 0; --count)
 177    {
 178       *result = *first;
 179       ++first;
 180       ++result;
 181    }
 182    return std::pair<InputIter, OutputIter>(first, result);
 183 }
 184
 185 template <class RAIter, class Size, class OutputIter>
 186 inline std::pair<RAIter, OutputIter>
 187 _copy_n(RAIter first, Size count, OutputIter result, std::random_access_iterator_tag)
 188 {
 189    RAIter last = first + count;
 190    return std::pair<RAIter, OutputIter>(last, std::copy(first, last, result));
 191 }
 192
 193 template <class InputIter, class Size, class OutputIter>
 194 inline std::pair<InputIter, OutputIter>
 195 _copy_n(InputIter first, Size count, OutputIter result)
 196 {
 197    return _copy_n(first, count, result, typename std::iterator_traits<InputIter>::iterator_category());
 198 }
 199
 200 template <class InputIter, class Size, class OutputIter>
 201 inline std::pair<InputIter, OutputIter>
 202 copy_n(InputIter first, Size count, OutputIter result)
 203 {
 204     return detail::_copy_n(first, count, result);
 205 }
 206
 207 /// \brief identity taken from SGI STL.
 208 template <typename T>
 209 struct identity
 210 {
 211     using argument_type = T;
 212     using result_type = T;
 213     const T& operator()(const T& val) const { return val; }
 214 };
 215
 216 /// \brief plus function object whose arguments may be of different type.
 217 template <typename T1, typename T2>
 218 struct plus_asymmetric {
 219     using first_argument_type = T1;
 220     using second_argument_type = T2;
 221     using result_type = T1;
 222     T1 operator()(T1 f1, T2 f2) const
 223     {
 224         return f1+f2;
 225     }
 226 };
 227
 228 /// \brief operator++ wrapped in a function object
 229 template <typename T>
 230 struct inc
 231 {
 232     using argument_type = T;
 233     using result_type = T;
 234     T operator()(T x) const { return ++x; }
 235 };
 236
 237 /// \brief operator-- wrapped in a function object
 238 template <typename T>
 239 struct dec
 240 {
 241     using argument_type = T;
 242     using result_type = T;
 243     T operator()(T x) const { return --x; }
 244 };
 245
 246 /// \brief Returns the index corresponding to the first occurrance of a given given type in
 247 //         a given Boost.MP11-compatible list (or size if the type is not present)
 248 template <typename Types, typename T>
 249 struct type_to_index : mp11::mp_find<Types, T>
 250 {
 251     static_assert(mp11::mp_contains<Types, T>::value, "T should be element of Types");
 252 };
 253
 254 } // namespace detail
 255
 256 /// \ingroup ColorSpaceAndLayoutModel
 257 /// \brief Represents a color space and ordering of channels in memory
 258 template
 259 <
 260     typename ColorSpace,
 261     typename ChannelMapping = mp11::mp_iota
 262     <
 263         std::integral_constant<int, mp11::mp_size<ColorSpace>::value>
 264     >
 265 >
 266 struct layout
 267 {
 268     using color_space_t = ColorSpace;
 269     using channel_mapping_t = ChannelMapping;
 270
 271     static_assert(mp11::mp_size<ColorSpace>::value > 0,
 272         "color space should not be empty sequence");
 273 };
 274
 275 /// \brief A version of swap that also works with reference proxy objects
 276 /// Where value_type<T1>  == value_type<T2> == Value
 277 template <typename Value, typename T1, typename T2>
 278 void swap_proxy(T1& left, T2& right)
 279 {
 280     Value tmp = left;
 281     left = right;
 282     right = tmp;
 283 }
 284
 285 /// \brief Run-time detection of whether the underlying architecture is little endian
 286 BOOST_FORCEINLINE bool little_endian()
 287 {
 288     short tester = 0x0001;
 289     return  *(char*)&tester!=0;
 290 }
 291 /// \brief Run-time detection of whether the underlying architecture is big endian
 292 BOOST_FORCEINLINE bool big_endian()
 293 {
 294     return !little_endian();
 295 }
 296
 297 }}  // namespace boost::gil
 298
 299 #endif