Generic Image Library: dynamic_at_c.hpp Source File

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dynamic_at_c.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_EXTENSION_DYNAMIC_IMAGE_DYNAMIC_AT_C_HPP
9#define BOOST_GIL_EXTENSION_DYNAMIC_IMAGE_DYNAMIC_AT_C_HPP
10
11#include <boost/gil/detail/mp11.hpp>
12
13#include <boost/preprocessor/facilities/empty.hpp>
14#include <boost/preprocessor/repetition/repeat.hpp>
15
16#include <stdexcept>
17
18namespace boost { namespace gil {
19
20// Constructs for static-to-dynamic integer convesion
21
22#define BOOST_GIL_AT_C_VALUE(z, N, text) mp11::mp_at_c<IntTypes, S+N>::value,
23#define BOOST_GIL_DYNAMIC_AT_C_LIMIT 226 // size of the maximum vector to handle
24
25#define BOOST_GIL_AT_C_LOOKUP(z, NUM, text) \
26 template<std::size_t S> \
27 struct at_c_fn<S,NUM> { \
28 template <typename IntTypes, typename ValueType> inline \
29 static ValueType apply(std::size_t index) { \
30 static ValueType table[] = { \
31 BOOST_PP_REPEAT(NUM, BOOST_GIL_AT_C_VALUE, BOOST_PP_EMPTY) \
32 }; \
33 return table[index]; \
34 } \
35 };
36
37namespace detail {
38 namespace at_c {
39 template <std::size_t START, std::size_t NUM> struct at_c_fn;
40 BOOST_PP_REPEAT(BOOST_GIL_DYNAMIC_AT_C_LIMIT, BOOST_GIL_AT_C_LOOKUP, BOOST_PP_EMPTY)
41
42 template <std::size_t QUOT> struct at_c_impl;
43
44 template <>
45 struct at_c_impl<0> {
46 template <typename IntTypes, typename ValueType> inline
47 static ValueType apply(std::size_t index) {
48 return at_c_fn<0, mp11::mp_size<IntTypes>::value>::template apply<IntTypes,ValueType>(index);
49 }
50 };
51
52 template <>
53 struct at_c_impl<1> {
54 template <typename IntTypes, typename ValueType> inline
55 static ValueType apply(std::size_t index) {
56 const std::size_t SIZE = mp11::mp_size<IntTypes>::value;
57 const std::size_t REM = SIZE % BOOST_GIL_DYNAMIC_AT_C_LIMIT;
58 switch (index / BOOST_GIL_DYNAMIC_AT_C_LIMIT) {
59 case 0: return at_c_fn<0 ,BOOST_GIL_DYNAMIC_AT_C_LIMIT-1>::template apply<IntTypes,ValueType>(index);
60 case 1: return at_c_fn<BOOST_GIL_DYNAMIC_AT_C_LIMIT ,REM >::template apply<IntTypes,ValueType>(index - BOOST_GIL_DYNAMIC_AT_C_LIMIT);
61 };
62 throw;
63 }
64 };
65
66 template <>
67 struct at_c_impl<2> {
68 template <typename IntTypes, typename ValueType> inline
69 static ValueType apply(std::size_t index) {
70 const std::size_t SIZE = mp11::mp_size<IntTypes>::value;
71 const std::size_t REM = SIZE % BOOST_GIL_DYNAMIC_AT_C_LIMIT;
72 switch (index / BOOST_GIL_DYNAMIC_AT_C_LIMIT) {
73 case 0: return at_c_fn<0 ,BOOST_GIL_DYNAMIC_AT_C_LIMIT-1>::template apply<IntTypes,ValueType>(index);
74 case 1: return at_c_fn<BOOST_GIL_DYNAMIC_AT_C_LIMIT ,BOOST_GIL_DYNAMIC_AT_C_LIMIT-1>::template apply<IntTypes,ValueType>(index - BOOST_GIL_DYNAMIC_AT_C_LIMIT);
75 case 2: return at_c_fn<BOOST_GIL_DYNAMIC_AT_C_LIMIT*2,REM >::template apply<IntTypes,ValueType>(index - BOOST_GIL_DYNAMIC_AT_C_LIMIT*2);
76 };
77 throw;
78 }
79 };
80
81 template <>
82 struct at_c_impl<3> {
83 template <typename IntTypes, typename ValueType> inline
84 static ValueType apply(std::size_t index) {
85 const std::size_t SIZE = mp11::mp_size<IntTypes>::value;
86 const std::size_t REM = SIZE % BOOST_GIL_DYNAMIC_AT_C_LIMIT;
87 switch (index / BOOST_GIL_DYNAMIC_AT_C_LIMIT) {
88 case 0: return at_c_fn<0 ,BOOST_GIL_DYNAMIC_AT_C_LIMIT-1>::template apply<IntTypes,ValueType>(index);
89 case 1: return at_c_fn<BOOST_GIL_DYNAMIC_AT_C_LIMIT ,BOOST_GIL_DYNAMIC_AT_C_LIMIT-1>::template apply<IntTypes,ValueType>(index - BOOST_GIL_DYNAMIC_AT_C_LIMIT);
90 case 2: return at_c_fn<BOOST_GIL_DYNAMIC_AT_C_LIMIT*2,BOOST_GIL_DYNAMIC_AT_C_LIMIT-1>::template apply<IntTypes,ValueType>(index - BOOST_GIL_DYNAMIC_AT_C_LIMIT*2);
91 case 3: return at_c_fn<BOOST_GIL_DYNAMIC_AT_C_LIMIT*3,REM >::template apply<IntTypes,ValueType>(index - BOOST_GIL_DYNAMIC_AT_C_LIMIT*3);
92 };
93 throw;
94 }
95 };
96 }
97}
98
106
107template <typename IntTypes, typename ValueType> inline
108ValueType at_c(std::size_t index) {
109 const std::size_t Size=mp11::mp_size<IntTypes>::value;
110 return detail::at_c::at_c_impl<Size/BOOST_GIL_DYNAMIC_AT_C_LIMIT>::template apply<IntTypes,ValueType>(index);
111}
112
113#undef BOOST_GIL_AT_C_VALUE
114#undef BOOST_GIL_DYNAMIC_AT_C_LIMIT
115#undef BOOST_GIL_AT_C_LOOKUP
116
117}} // namespace boost::gil
118
119#endif
boost
defined(BOOST_NO_CXX17_HDR_MEMORY_RESOURCE)
Definition algorithm.hpp:36