boost/gil/bit_aligned_pixel_iterator.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://opensource.adobe.com/gil for most recent version including documentation.
   9 */
  10
  11 /*************************************************************************************************/
  12
  13 #ifndef GIL_BIT_ALIGNED_PIXEL_ITERATOR_HPP
  14 #define GIL_BIT_ALIGNED_PIXEL_ITERATOR_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/iterator/iterator_facade.hpp>
  27 #include "gil_config.hpp"
  28 #include "bit_aligned_pixel_reference.hpp"
  29 #include "pixel_iterator.hpp"
  30
  31 namespace boost { namespace gil {
  32
  33 /// \defgroup PixelIteratorNonAlignedPixelIterator bit_aligned_pixel_iterator
  34 /// \ingroup PixelIteratorModel
  35 /// \brief An iterator over non-byte-aligned pixels. Models PixelIteratorConcept, PixelBasedConcept, MemoryBasedIteratorConcept, HasDynamicXStepTypeConcept
  36
  37 ////////////////////////////////////////////////////////////////////////////////////////
  38 /// \brief An iterator over non-byte-aligned pixels. Models PixelIteratorConcept, PixelBasedConcept, MemoryBasedIteratorConcept, HasDynamicXStepTypeConcept
  39 ///
  40 /// An iterator over pixels that correspond to non-byte-aligned bit ranges. Examples of such pixels are single bit grayscale pixel, or a 6-bit RGB 222 pixel.
  41 ///
  42 /// \ingroup PixelIteratorNonAlignedPixelIterator PixelBasedModel
  43
  44 template <typename NonAlignedPixelReference>
  45 struct bit_aligned_pixel_iterator : public iterator_facade<bit_aligned_pixel_iterator<NonAlignedPixelReference>,
  46                                                   typename NonAlignedPixelReference::value_type,
  47                                                   std::random_access_iterator_tag,
  48                                                   const NonAlignedPixelReference,
  49                                                   typename NonAlignedPixelReference::bit_range_t::difference_type> {
  50 private:
  51     typedef iterator_facade<bit_aligned_pixel_iterator<NonAlignedPixelReference>,
  52                             typename NonAlignedPixelReference::value_type,
  53                             std::random_access_iterator_tag,
  54                             const NonAlignedPixelReference,
  55                             typename NonAlignedPixelReference::bit_range_t::difference_type> parent_t;
  56     template <typename Ref> friend struct bit_aligned_pixel_iterator;
  57
  58     typedef typename NonAlignedPixelReference::bit_range_t bit_range_t;
  59 public:
  60     typedef typename parent_t::difference_type             difference_type;
  61     typedef typename parent_t::reference                   reference;
  62
  63     bit_aligned_pixel_iterator() {}
  64     bit_aligned_pixel_iterator(const bit_aligned_pixel_iterator& p) : _bit_range(p._bit_range) {}
  65     bit_aligned_pixel_iterator& operator=(const bit_aligned_pixel_iterator& p) { _bit_range=p._bit_range; return *this; }
  66
  67     template <typename Ref> bit_aligned_pixel_iterator(const bit_aligned_pixel_iterator<Ref>& p) : _bit_range(p._bit_range) {}
  68
  69     bit_aligned_pixel_iterator(reference* ref) : _bit_range(ref->bit_range()) {}
  70     explicit bit_aligned_pixel_iterator(typename bit_range_t::byte_t* data, int bit_offset=0) : _bit_range(data,bit_offset) {}
  71
  72     /// For some reason operator[] provided by iterator_adaptor returns a custom class that is convertible to reference
  73     /// We require our own reference because it is registered in iterator_traits
  74     reference operator[](difference_type d) const { bit_aligned_pixel_iterator it=*this; it.advance(d); return *it; }
  75
  76     reference operator->()         const { return **this; }
  77     const bit_range_t& bit_range() const { return _bit_range; }
  78           bit_range_t& bit_range()       { return _bit_range; }
  79 private:
  80     bit_range_t _bit_range;
  81     BOOST_STATIC_CONSTANT(int, bit_size = NonAlignedPixelReference::bit_size);
  82
  83     friend class boost::iterator_core_access;
  84     reference dereference()     const { return NonAlignedPixelReference(_bit_range); }
  85     void increment()                  { ++_bit_range; }
  86     void decrement()                  { --_bit_range; }
  87     void advance(difference_type d)   { _bit_range.bit_advance(d*bit_size); }
  88
  89     difference_type distance_to(const bit_aligned_pixel_iterator& it) const { return _bit_range.bit_distance_to(it._bit_range) / bit_size; }
  90     bool equal(const bit_aligned_pixel_iterator& it) const { return _bit_range==it._bit_range; }
  91 };
  92
  93 template <typename NonAlignedPixelReference>
  94 struct const_iterator_type<bit_aligned_pixel_iterator<NonAlignedPixelReference> > {
  95     typedef bit_aligned_pixel_iterator<typename NonAlignedPixelReference::const_reference> type;
  96 };
  97
  98 template <typename NonAlignedPixelReference>
  99 struct iterator_is_mutable<bit_aligned_pixel_iterator<NonAlignedPixelReference> > : public mpl::bool_<NonAlignedPixelReference::is_mutable> {};
 100
 101 template <typename NonAlignedPixelReference>
 102 struct is_iterator_adaptor<bit_aligned_pixel_iterator<NonAlignedPixelReference> > : public mpl::false_ {};
 103
 104 /////////////////////////////
 105 //  PixelBasedConcept
 106 /////////////////////////////
 107
 108 template <typename NonAlignedPixelReference>
 109 struct color_space_type<bit_aligned_pixel_iterator<NonAlignedPixelReference> > : public color_space_type<NonAlignedPixelReference> {};
 110
 111 template <typename NonAlignedPixelReference>
 112 struct channel_mapping_type<bit_aligned_pixel_iterator<NonAlignedPixelReference> > : public channel_mapping_type<NonAlignedPixelReference> {};
 113
 114 template <typename NonAlignedPixelReference>
 115 struct is_planar<bit_aligned_pixel_iterator<NonAlignedPixelReference> > : public is_planar<NonAlignedPixelReference> {}; // == false
 116
 117 /////////////////////////////
 118 //  MemoryBasedIteratorConcept
 119 /////////////////////////////
 120
 121 template <typename NonAlignedPixelReference>
 122 struct byte_to_memunit<bit_aligned_pixel_iterator<NonAlignedPixelReference> > : public mpl::int_<8> {};
 123
 124 template <typename NonAlignedPixelReference>
 125 inline std::ptrdiff_t memunit_step(const bit_aligned_pixel_iterator<NonAlignedPixelReference>&) {
 126     return NonAlignedPixelReference::bit_size;
 127 }
 128
 129 template <typename NonAlignedPixelReference>
 130 inline std::ptrdiff_t memunit_distance(const bit_aligned_pixel_iterator<NonAlignedPixelReference>& p1, const bit_aligned_pixel_iterator<NonAlignedPixelReference>& p2) {
 131     return (p2.bit_range().current_byte() - p1.bit_range().current_byte())*8 + p2.bit_range().bit_offset() - p1.bit_range().bit_offset();
 132 }
 133
 134 template <typename NonAlignedPixelReference>
 135 inline void memunit_advance(bit_aligned_pixel_iterator<NonAlignedPixelReference>& p, std::ptrdiff_t diff) {
 136     p.bit_range().bit_advance(diff);
 137 }
 138
 139 template <typename NonAlignedPixelReference>
 140 inline bit_aligned_pixel_iterator<NonAlignedPixelReference> memunit_advanced(const bit_aligned_pixel_iterator<NonAlignedPixelReference>& p, std::ptrdiff_t diff) {
 141     bit_aligned_pixel_iterator<NonAlignedPixelReference> ret=p;
 142     memunit_advance(ret, diff);
 143     return ret;
 144 }
 145
 146 template <typename NonAlignedPixelReference> inline
 147 NonAlignedPixelReference memunit_advanced_ref(bit_aligned_pixel_iterator<NonAlignedPixelReference> it, std::ptrdiff_t diff) {
 148     return *memunit_advanced(it,diff);
 149 }
 150 /////////////////////////////
 151 //  HasDynamicXStepTypeConcept
 152 /////////////////////////////
 153
 154 template <typename NonAlignedPixelReference>
 155 struct dynamic_x_step_type<bit_aligned_pixel_iterator<NonAlignedPixelReference> > {
 156     typedef memory_based_step_iterator<bit_aligned_pixel_iterator<NonAlignedPixelReference> > type;
 157 };
 158
 159 /////////////////////////////
 160 //  iterator_type_from_pixel
 161 /////////////////////////////
 162
 163 template <typename B, typename C, typename L, bool M>
 164 struct iterator_type_from_pixel<const bit_aligned_pixel_reference<B,C,L,M>,false,false,false> {
 165     typedef bit_aligned_pixel_iterator<bit_aligned_pixel_reference<B,C,L,false> > type;
 166 };
 167
 168 template <typename B, typename C, typename L, bool M>
 169 struct iterator_type_from_pixel<const bit_aligned_pixel_reference<B,C,L,M>,false,false,true> {
 170     typedef bit_aligned_pixel_iterator<bit_aligned_pixel_reference<B,C,L,true> > type;
 171 };
 172
 173 template <typename B, typename C, typename L, bool M, bool IsPlanar, bool IsStep, bool IsMutable>
 174 struct iterator_type_from_pixel<bit_aligned_pixel_reference<B,C,L,M>,IsPlanar,IsStep,IsMutable>
 175     : public iterator_type_from_pixel<const bit_aligned_pixel_reference<B,C,L,M>,IsPlanar,IsStep,IsMutable> {};
 176
 177 } }  // namespace boost::gil
 178
 179 namespace std {
 180
 181 // It is important to provide an overload of uninitialized_copy for bit_aligned_pixel_iterator. The default STL implementation calls placement new,
 182 // which is not defined for bit_aligned_pixel_iterator.
 183 template <typename NonAlignedPixelReference>
 184 boost::gil::bit_aligned_pixel_iterator<NonAlignedPixelReference> uninitialized_copy(boost::gil::bit_aligned_pixel_iterator<NonAlignedPixelReference> first,
 185                                                                                    boost::gil::bit_aligned_pixel_iterator<NonAlignedPixelReference> last,
 186                                                                                    boost::gil::bit_aligned_pixel_iterator<NonAlignedPixelReference> dst) {
 187     return std::copy(first,last,dst);
 188 }
 189
 190 }   // namespace std
 191 #endif