Generic Image Library: conversion_policies.hpp Source File

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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
19namespace boost{ namespace gil { namespace detail {
20
21struct read_and_no_convert
22{
23public:
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
59template<typename CC>
60struct read_and_convert
61{
62public:
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
96template< typename Conversion_Policy >
97 struct is_read_only : std::false_type {};
98
99template<>
100struct is_read_only<detail::read_and_no_convert> : std::true_type {};
101
102} // namespace detail
103} // namespace gil
104} // namespace boost
105
106#endif
std::copy
BOOST_FORCEINLINE auto copy(boost::gil::pixel< T, CS > *first, boost::gil::pixel< T, CS > *last, boost::gil::pixel< T, CS > *dst) -> boost::gil::pixel< T, CS > *
Copy when both src and dst are interleaved and of the same type can be just memmove.
Definition algorithm.hpp:145
boost
defined(BOOST_NO_CXX17_HDR_MEMORY_RESOURCE)
Definition algorithm.hpp:36
boost::gil::detail::is_read_only
Determines if reader type is read only ( no conversion ).
Definition conversion_policies.hpp:97