Generic Image Library : pixel_iterator.hpp Source File

00001 /*
00002     Copyright 2005-2007 Adobe Systems Incorporated
00003    
00004     Use, modification and distribution are subject to the Boost Software License,
00005     Version 1.0. (See accompanying file LICENSE_1_0.txt or copy at
00006     http://www.boost.org/LICENSE_1_0.txt).
00007 
00008     See http://opensource.adobe.com/gil for most recent version including documentation.
00009 */
00010 
00011 /*************************************************************************************************/
00012 
00013 #ifndef GIL_PIXEL_ITERATOR_H
00014 #define GIL_PIXEL_ITERATOR_H
00015 
00024 
00025 #include <cassert>
00026 #include <iterator>
00027 #include "gil_config.hpp"
00028 #include "gil_concept.hpp"
00029 #include "pixel.hpp"
00030 
00031 namespace boost { namespace gil {
00032 
00033 //forwarded declaration (as this file is included in step_iterator.hpp)
00034 template <typename Iterator>
00035 class memory_based_step_iterator;
00036 
00037 template <typename Iterator> struct dynamic_x_step_type;
00038 
00041 template <typename It>
00042 struct is_iterator_adaptor : public mpl::false_{};
00043 
00045 template <typename It>
00046 struct iterator_adaptor_get_base;
00047 
00049 template <typename It, typename NewBaseIt>
00050 struct iterator_adaptor_rebind;
00051 
00053 template <typename It>
00054 struct const_iterator_type;
00055 
00056 // The default implementation when the iterator is a C pointer is to use the standard constness semantics
00057 template <typename T> struct const_iterator_type<      T*> { typedef const T* type; };
00058 template <typename T> struct const_iterator_type<const T*> { typedef const T* type; };
00059 
00062 template <typename It>
00063 struct iterator_is_mutable{};
00064 
00065 // The default implementation when the iterator is a C pointer is to use the standard constness semantics
00066 template <typename T> struct iterator_is_mutable<      T*> : public mpl::true_{};
00067 template <typename T> struct iterator_is_mutable<const T*> : public mpl::false_{};
00068 
00073 
00074 
00075 
00077 //  HasDynamicXStepTypeConcept
00079 
00081 template <typename Pixel>
00082 struct dynamic_x_step_type<Pixel*> {
00083     typedef memory_based_step_iterator<Pixel*> type;
00084 };
00085 
00087 template <typename Pixel>
00088 struct dynamic_x_step_type<const Pixel*> {
00089     typedef memory_based_step_iterator<const Pixel*> type;
00090 };
00091 
00092 
00094 //  PixelBasedConcept
00096 
00097 template <typename Pixel> struct color_space_type<      Pixel*> : public color_space_type<Pixel> {};
00098 template <typename Pixel> struct color_space_type<const Pixel*> : public color_space_type<Pixel> {};
00099 
00100 template <typename Pixel> struct channel_mapping_type<      Pixel*> : public channel_mapping_type<Pixel> {};
00101 template <typename Pixel> struct channel_mapping_type<const Pixel*> : public channel_mapping_type<Pixel> {};
00102 
00103 template <typename Pixel> struct is_planar<      Pixel*> : public is_planar<Pixel> {};
00104 template <typename Pixel> struct is_planar<const Pixel*> : public is_planar<Pixel> {};
00105 
00107 //  HomogeneousPixelBasedConcept
00109 
00110 template <typename Pixel> struct channel_type<Pixel*> : public channel_type<Pixel> {};
00111 template <typename Pixel> struct channel_type<const Pixel*> : public channel_type<Pixel> {};
00112 
00119 
00121 //  MemoryBasedIteratorConcept
00123 
00124 template <typename T>
00125 struct byte_to_memunit : public mpl::int_<1> {};
00126 
00127 template <typename P>
00128 inline std::ptrdiff_t memunit_step(const P*) { return sizeof(P); }
00129 
00130 template <typename P>
00131 inline std::ptrdiff_t memunit_distance(const P* p1, const P* p2) { 
00132     return (gil_reinterpret_cast_c<const unsigned char*>(p2)-gil_reinterpret_cast_c<const unsigned char*>(p1)); 
00133 }
00134 
00135 template <typename P> P* memunit_advanced(const P* p, std::ptrdiff_t diff);
00136 
00137 template <typename P>
00138 inline void memunit_advance(P* &p, std::ptrdiff_t diff) { 
00139     p=(P*)((unsigned char*)(p)+diff);
00140 }
00141 
00142 template <typename P>
00143 inline P* memunit_advanced(const P* p, std::ptrdiff_t diff) {
00144     return (P*)((unsigned char*)(p)+diff);
00145 }
00146 
00147 
00148 //  memunit_advanced_ref
00149 //  (shortcut to advancing a pointer by a given number of memunits and taking the reference in case the compiler is not smart enough)
00150 
00151 template <typename P>
00152 inline P& memunit_advanced_ref(P* p, std::ptrdiff_t diff) {
00153     return *memunit_advanced(p,diff);
00154 }
00155 
00156 } }  // namespace boost::gil
00157 
00158 #endif