ceph/src/boost/boost/gil/bit_aligned_pixel_reference.hpp

   1 /*
   2     Copyright 2005-2007 Adobe Systems Incorporated
   3
   4     Use, modification and distribution are subject to the Boost Software License,
   5     Version 1.0. (See accompanying file LICENSE_1_0.txt or copy at
   6     http://www.boost.org/LICENSE_1_0.txt).
   7
   8     See http://stlab.adobe.com/gil for most recent version including documentation.
   9 */
  10
  11 /*************************************************************************************************/
  12
  13 #ifndef GIL_BIT_ALIGNED_PIXEL_REFERENCE_HPP
  14 #define GIL_BIT_ALIGNED_PIXEL_REFERENCE_HPP
  15
  16 ////////////////////////////////////////////////////////////////////////////////////////
  17 /// \file
  18 /// \brief A model of a heterogeneous pixel that is not byte aligned. Examples are bitmap (1-bit pixels) or 6-bit RGB (222)
  19 /// \author Lubomir Bourdev and Hailin Jin \n
  20 ///         Adobe Systems Incorporated
  21 /// \date   2005-2007 \n Last updated on September 28, 2006
  22 ///
  23 ////////////////////////////////////////////////////////////////////////////////////////
  24
  25 #include <functional>
  26 #include <boost/mpl/accumulate.hpp>
  27 #include <boost/mpl/at.hpp>
  28 #include <boost/mpl/bool.hpp>
  29 #include <boost/mpl/if.hpp>
  30 #include <boost/mpl/plus.hpp>
  31 #include <boost/mpl/push_back.hpp>
  32 #include <boost/mpl/vector.hpp>
  33 #include "gil_config.hpp"
  34 #include "pixel.hpp"
  35 #include "channel.hpp"
  36
  37 namespace boost { namespace gil {
  38
  39 /////////////////////////////
  40 //  bit_range
  41 //
  42 //  Represents a range of bits that can span multiple consecutive bytes. The range has a size fixed at compile time, but the offset is specified at run time.
  43 /////////////////////////////
  44
  45 template <int RangeSize, bool Mutable>
  46 class bit_range {
  47 public:
  48     typedef typename mpl::if_c<Mutable,unsigned char,const unsigned char>::type byte_t;
  49     typedef std::ptrdiff_t difference_type;
  50     template <int RS, bool M> friend class bit_range;
  51 private:
  52     byte_t* _current_byte;   // the starting byte of the bit range
  53     int     _bit_offset;     // offset from the beginning of the current byte. 0<=_bit_offset<=7
  54
  55 public:
  56     bit_range() : _current_byte(NULL), _bit_offset(0) {}
  57     bit_range(byte_t* current_byte, int bit_offset) : _current_byte(current_byte), _bit_offset(bit_offset) { assert(bit_offset>=0 && bit_offset<8); }
  58
  59     bit_range(const bit_range& br) : _current_byte(br._current_byte), _bit_offset(br._bit_offset) {}
  60     template <bool M> bit_range(const bit_range<RangeSize,M>& br) : _current_byte(br._current_byte), _bit_offset(br._bit_offset) {}
  61
  62     bit_range& operator=(const bit_range& br) { _current_byte = br._current_byte; _bit_offset=br._bit_offset; return *this; }
  63     bool operator==(const bit_range& br) const { return  _current_byte==br._current_byte && _bit_offset==br._bit_offset; }
  64
  65     bit_range& operator++() {
  66         _current_byte += (_bit_offset+RangeSize) / 8;
  67         _bit_offset    = (_bit_offset+RangeSize) % 8;
  68         return *this;
  69     }
  70     bit_range& operator--() { bit_advance(-RangeSize); return *this; }
  71
  72     void bit_advance(difference_type num_bits) {
  73         int new_offset = int(_bit_offset+num_bits);
  74         _current_byte += new_offset / 8;
  75         _bit_offset    = new_offset % 8;
  76         if (_bit_offset<0) {
  77             _bit_offset+=8;
  78             --_current_byte;
  79         }
  80     }
  81     difference_type bit_distance_to(const bit_range& b) const {
  82         return (b.current_byte() - current_byte())*8 + b.bit_offset()-bit_offset();
  83     }
  84     byte_t* current_byte() const { return _current_byte; }
  85     int     bit_offset()   const { return _bit_offset; }
  86 };
  87
  88
  89 /// \defgroup ColorBaseModelNonAlignedPixel bit_aligned_pixel_reference
  90 /// \ingroup ColorBaseModel
  91 /// \brief A heterogeneous color base representing pixel that may not be byte aligned, i.e. it may correspond to a bit range that does not start/end at a byte boundary. Models ColorBaseConcept.
  92
  93 /**
  94 \defgroup PixelModelNonAlignedPixel bit_aligned_pixel_reference
  95 \ingroup PixelModel
  96 \brief A heterogeneous pixel reference used to represent non-byte-aligned pixels. Models PixelConcept
  97
  98 Example:
  99 \code
 100 unsigned char data=0;
 101
 102 // A mutable reference to a 6-bit BGR pixel in "123" format (1 bit for red, 2 bits for green, 3 bits for blue)
 103 typedef const bit_aligned_pixel_reference<unsigned char, mpl::vector3_c<int,1,2,3>, rgb_layout_t, true>  rgb123_ref_t;
 104
 105 // create the pixel reference at bit offset 2
 106 // (i.e. red = [2], green = [3,4], blue = [5,6,7] bits)
 107 rgb123_ref_t ref(&data, 2);
 108 get_color(ref, red_t()) = 1;
 109 assert(data == 0x04);
 110 get_color(ref, green_t()) = 3;
 111 assert(data == 0x1C);
 112 get_color(ref, blue_t()) = 7;
 113 assert(data == 0xFC);
 114 \endcode
 115 */
 116 /// \ingroup ColorBaseModelNonAlignedPixel PixelModelNonAlignedPixel PixelBasedModel
 117 /// \brief Heterogeneous pixel reference corresponding to non-byte-aligned bit range. Models ColorBaseConcept, PixelConcept, PixelBasedConcept
 118 template <typename BitField,
 119           typename ChannelBitSizes,  // MPL integral vector defining the number of bits for each channel. For example, for 565RGB, vector_c<int,5,6,5>
 120           typename Layout,
 121           bool IsMutable>
 122 struct bit_aligned_pixel_reference {
 123     BOOST_STATIC_CONSTANT(int, bit_size = (mpl::accumulate<ChannelBitSizes, mpl::int_<0>, mpl::plus<mpl::_1, mpl::_2> >::type::value));
 124     typedef boost::gil::bit_range<bit_size,IsMutable>                                           bit_range_t;
 125     typedef BitField                                                                bitfield_t;
 126     typedef typename mpl::if_c<IsMutable,unsigned char*,const unsigned char*>::type data_ptr_t;
 127
 128     typedef Layout layout_t;
 129
 130     typedef typename packed_pixel_type<bitfield_t,ChannelBitSizes,Layout>::type       value_type;
 131     typedef const bit_aligned_pixel_reference                                         reference;
 132     typedef const bit_aligned_pixel_reference<BitField,ChannelBitSizes,Layout,false>  const_reference;
 133
 134     BOOST_STATIC_CONSTANT(bool, is_mutable = IsMutable);
 135
 136     bit_aligned_pixel_reference(){}
 137     bit_aligned_pixel_reference(data_ptr_t data_ptr, int bit_offset)   : _bit_range(data_ptr, bit_offset) {}
 138     explicit bit_aligned_pixel_reference(const bit_range_t& bit_range) : _bit_range(bit_range) {}
 139     template <bool IsMutable2> bit_aligned_pixel_reference(const bit_aligned_pixel_reference<BitField,ChannelBitSizes,Layout,IsMutable2>& p) : _bit_range(p._bit_range) {}
 140
 141     // Grayscale references can be constructed from the channel reference
 142     explicit bit_aligned_pixel_reference(const typename kth_element_type<bit_aligned_pixel_reference,0>::type channel0) : _bit_range(static_cast<data_ptr_t>(&channel0), channel0.first_bit()) {
 143         BOOST_STATIC_ASSERT((num_channels<bit_aligned_pixel_reference>::value==1));
 144     }
 145
 146     // Construct from another compatible pixel type
 147     bit_aligned_pixel_reference(const bit_aligned_pixel_reference& p) : _bit_range(p._bit_range) {}
 148     template <typename BF, typename CR> bit_aligned_pixel_reference(packed_pixel<BF,CR,Layout>& p) : _bit_range(static_cast<data_ptr_t>(&gil::at_c<0>(p)), gil::at_c<0>(p).first_bit()) {
 149         check_compatible<packed_pixel<BF,CR,Layout> >();
 150     }
 151
 152     const bit_aligned_pixel_reference& operator=(const bit_aligned_pixel_reference& p) const { static_copy(p,*this); return *this; }
 153     template <typename P> const bit_aligned_pixel_reference& operator=(const P& p) const { assign(p, mpl::bool_<is_pixel<P>::value>()); return *this; }
 154
 155     template <typename P> bool operator==(const P& p) const { return equal(p, mpl::bool_<is_pixel<P>::value>()); }
 156     template <typename P> bool operator!=(const P& p) const { return !(*this==p); }
 157
 158     const bit_aligned_pixel_reference* operator->()    const { return this; }
 159
 160     const bit_range_t& bit_range() const { return _bit_range; }
 161 private:
 162     mutable bit_range_t _bit_range;
 163     template <typename B, typename C, typename L, bool M> friend struct bit_aligned_pixel_reference;
 164
 165     template <typename Pixel> static void check_compatible() { gil_function_requires<PixelsCompatibleConcept<Pixel,bit_aligned_pixel_reference> >(); }
 166
 167     template <typename Pixel> void assign(const Pixel& p, mpl::true_) const { check_compatible<Pixel>(); static_copy(p,*this); }
 168     template <typename Pixel> bool  equal(const Pixel& p, mpl::true_) const { check_compatible<Pixel>(); return static_equal(*this,p); }
 169
 170 private:
 171     static void check_gray() {  BOOST_STATIC_ASSERT((is_same<typename Layout::color_space_t, gray_t>::value)); }
 172     template <typename Channel> void assign(const Channel& chan, mpl::false_) const { check_gray(); gil::at_c<0>(*this)=chan; }
 173     template <typename Channel> bool equal (const Channel& chan, mpl::false_) const { check_gray(); return gil::at_c<0>(*this)==chan; }
 174 };
 175
 176 /////////////////////////////
 177 //  ColorBasedConcept
 178 /////////////////////////////
 179
 180 template <typename BitField, typename ChannelBitSizes, typename L, bool IsMutable, int K>
 181 struct kth_element_type<bit_aligned_pixel_reference<BitField,ChannelBitSizes,L,IsMutable>, K> {
 182 public:
 183     typedef const packed_dynamic_channel_reference<BitField, mpl::at_c<ChannelBitSizes,K>::type::value, IsMutable> type;
 184 };
 185
 186 template <typename B, typename C, typename L, bool M, int K>
 187 struct kth_element_reference_type<bit_aligned_pixel_reference<B,C,L,M>, K>
 188     : public kth_element_type<bit_aligned_pixel_reference<B,C,L,M>, K> {};
 189
 190 template <typename B, typename C, typename L, bool M, int K>
 191 struct kth_element_const_reference_type<bit_aligned_pixel_reference<B,C,L,M>, K>
 192     : public kth_element_type<bit_aligned_pixel_reference<B,C,L,M>, K> {};
 193
 194
 195 namespace detail {
 196     // returns sum of IntegralVector[0] ... IntegralVector[K-1]
 197     template <typename IntegralVector, int K>
 198     struct sum_k : public mpl::plus<sum_k<IntegralVector,K-1>, typename mpl::at_c<IntegralVector,K-1>::type > {};
 199
 200     template <typename IntegralVector> struct sum_k<IntegralVector,0> : public mpl::int_<0> {};
 201 }
 202
 203 // at_c required by MutableColorBaseConcept
 204 template <int K, typename BitField, typename ChannelBitSizes, typename L, bool Mutable> inline
 205 typename kth_element_reference_type<bit_aligned_pixel_reference<BitField,ChannelBitSizes,L,Mutable>,K>::type
 206 at_c(const bit_aligned_pixel_reference<BitField,ChannelBitSizes,L,Mutable>& p) {
 207     typedef bit_aligned_pixel_reference<BitField,ChannelBitSizes,L,Mutable> pixel_t;
 208     typedef typename kth_element_reference_type<pixel_t,K>::type channel_t;
 209     typedef typename pixel_t::bit_range_t bit_range_t;
 210
 211     bit_range_t bit_range(p.bit_range());
 212     bit_range.bit_advance(detail::sum_k<ChannelBitSizes,K>::value);
 213
 214     return channel_t(bit_range.current_byte(), bit_range.bit_offset());
 215 }
 216
 217 /////////////////////////////
 218 //  PixelConcept
 219 /////////////////////////////
 220
 221 /// Metafunction predicate that flags bit_aligned_pixel_reference as a model of PixelConcept. Required by PixelConcept
 222 template <typename B, typename C, typename L, bool M>
 223 struct is_pixel<bit_aligned_pixel_reference<B,C,L,M> > : public mpl::true_{};
 224
 225 /////////////////////////////
 226 //  PixelBasedConcept
 227 /////////////////////////////
 228
 229 template <typename B, typename C, typename L, bool M>
 230 struct color_space_type<bit_aligned_pixel_reference<B,C,L,M> > {
 231     typedef typename L::color_space_t type;
 232 };
 233
 234 template <typename B, typename C, typename L, bool M>
 235 struct channel_mapping_type<bit_aligned_pixel_reference<B,C,L,M> > {
 236     typedef typename L::channel_mapping_t type;
 237 };
 238
 239 template <typename B, typename C, typename L, bool M>
 240 struct is_planar<bit_aligned_pixel_reference<B,C,L,M> > : mpl::false_ {};
 241
 242 /////////////////////////////
 243 //  pixel_reference_type
 244 /////////////////////////////
 245
 246 namespace detail {
 247     // returns a vector containing K copies of the type T
 248     template <unsigned K, typename T> struct k_copies;
 249     template <typename T> struct k_copies<0,T> {
 250         typedef mpl::vector0<> type;
 251     };
 252     template <unsigned K, typename T> struct k_copies : public mpl::push_back<typename k_copies<K-1,T>::type, T> {};
 253 }
 254
 255 // Constructs a homogeneous bit_aligned_pixel_reference given a channel reference
 256 template <typename BitField, int NumBits, typename Layout>
 257 struct pixel_reference_type<const packed_dynamic_channel_reference<BitField,NumBits,false>, Layout, false, false> {
 258 private:
 259     typedef typename mpl::size<typename Layout::color_space_t>::type size_t;
 260     typedef typename detail::k_copies<size_t::value,mpl::integral_c<unsigned,NumBits> >::type channel_bit_sizes_t;
 261 public:
 262     typedef bit_aligned_pixel_reference<BitField, channel_bit_sizes_t, Layout, false> type;
 263 };
 264
 265 // Same but for the mutable case. We cannot combine the mutable and read-only cases because this triggers ambiguity
 266 template <typename BitField, int NumBits, typename Layout>
 267 struct pixel_reference_type<const packed_dynamic_channel_reference<BitField,NumBits,true>, Layout, false, true> {
 268 private:
 269     typedef typename mpl::size<typename Layout::color_space_t>::type size_t;
 270     typedef typename detail::k_copies<size_t::value,mpl::integral_c<unsigned,NumBits> >::type channel_bit_sizes_t;
 271 public:
 272     typedef bit_aligned_pixel_reference<BitField, channel_bit_sizes_t, Layout, true> type;
 273 };
 274
 275 } }  // namespace boost::gil
 276
 277 namespace std {
 278 // We are forced to define swap inside std namespace because on some platforms (Visual Studio 8) STL calls swap qualified.
 279 // swap with 'left bias':
 280 // - swap between proxy and anything
 281 // - swap between value type and proxy
 282 // - swap between proxy and proxy
 283 // Having three overloads allows us to swap between different (but compatible) models of PixelConcept
 284
 285 template <typename B, typename C, typename L, typename R> inline
 286 void swap(const boost::gil::bit_aligned_pixel_reference<B,C,L,true> x, R& y) {
 287     boost::gil::swap_proxy<typename boost::gil::bit_aligned_pixel_reference<B,C,L,true>::value_type>(x,y);
 288 }
 289
 290
 291 template <typename B, typename C, typename L> inline
 292 void swap(typename boost::gil::bit_aligned_pixel_reference<B,C,L,true>::value_type& x, const boost::gil::bit_aligned_pixel_reference<B,C,L,true> y) {
 293     boost::gil::swap_proxy<typename boost::gil::bit_aligned_pixel_reference<B,C,L,true>::value_type>(x,y);
 294 }
 295
 296
 297 template <typename B, typename C, typename L> inline
 298 void swap(const boost::gil::bit_aligned_pixel_reference<B,C,L,true> x, const boost::gil::bit_aligned_pixel_reference<B,C,L,true> y) {
 299     boost::gil::swap_proxy<typename boost::gil::bit_aligned_pixel_reference<B,C,L,true>::value_type>(x,y);
 300 }
 301 }   // namespace std
 302 #endif