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# dynamic_at_c.hpp

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    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_DYNAMIC_AT_C_HPP
    00014 #define GIL_DYNAMIC_AT_C_HPP
    00015
    00016 #include "../../gil_config.hpp"
    00017 #include <cassert>
    00018 #include <stdexcept>
    00019 #include <boost/mpl/at.hpp>
    00020 #include <boost/mpl/size.hpp>
    00021
    00022
    00031
    00032 namespace boost { namespace gil {
    00033
    00034 #define GIL_AT_C_VALUE(z, N, text)    mpl::at_c<IntTypes,S+N>::type::value,
    00035 #define GIL_DYNAMIC_AT_C_LIMIT        226    // size of the maximum vector to handle
    00036
    00037 #define GIL_AT_C_LOOKUP(z, NUM, text)                                   \
    00038     template<std::size_t S>                                             \
    00039     struct at_c_fn<S,NUM> {                                             \
    00040     template <typename IntTypes, typename ValueType> inline           \
    00041         static ValueType apply(std::size_t index) {                    \
    00042             static ValueType table[] = {                               \
    00043                 BOOST_PP_REPEAT(NUM, GIL_AT_C_VALUE, BOOST_PP_EMPTY)    \
    00044             };                                                          \
    00045             return table[index];                                        \
    00046         }                                                               \
    00047     };
    00048
    00049 namespace detail {
    00050     namespace at_c {
    00051         template <std::size_t START, std::size_t NUM> struct at_c_fn;
    00052         BOOST_PP_REPEAT(GIL_DYNAMIC_AT_C_LIMIT, GIL_AT_C_LOOKUP, BOOST_PP_EMPTY)
    00053
    00054         template <std::size_t QUOT> struct at_c_impl;
    00055
    00056         template <>
    00057         struct at_c_impl<0> {
    00058             template <typename IntTypes, typename ValueType> inline
    00059             static ValueType apply(std::size_t index) {
    00060                 return at_c_fn<0,mpl::size<IntTypes>::value>::template apply<IntTypes,ValueType>(index);
    00061             }
    00062         };
    00063
    00064         template <>
    00065         struct at_c_impl<1> {
    00066             template <typename IntTypes, typename ValueType> inline
    00067             static ValueType apply(std::size_t index) {
    00068                 const std::size_t SIZE=mpl::size<IntTypes>::value;
    00069                 const std::size_t REM = SIZE % GIL_DYNAMIC_AT_C_LIMIT;
    00070                 switch (index / GIL_DYNAMIC_AT_C_LIMIT) {
    00071                     case 0: return at_c_fn<0                   ,GIL_DYNAMIC_AT_C_LIMIT-1>::template apply<IntTypes,ValueType>(index);
    00072                     case 1: return at_c_fn<GIL_DYNAMIC_AT_C_LIMIT  ,REM                 >::template apply<IntTypes,ValueType>(index - GIL_DYNAMIC_AT_C_LIMIT);
    00073                 };
    00074                 throw;
    00075             }
    00076         };
    00077
    00078         template <>
    00079         struct at_c_impl<2> {
    00080             template <typename IntTypes, typename ValueType> inline
    00081             static ValueType apply(std::size_t index) {
    00082                 const std::size_t SIZE=mpl::size<IntTypes>::value;
    00083                 const std::size_t REM = SIZE % GIL_DYNAMIC_AT_C_LIMIT;
    00084                 switch (index / GIL_DYNAMIC_AT_C_LIMIT) {
    00085                     case 0: return at_c_fn<0                   ,GIL_DYNAMIC_AT_C_LIMIT-1>::template apply<IntTypes,ValueType>(index);
    00086                     case 1: return at_c_fn<GIL_DYNAMIC_AT_C_LIMIT  ,GIL_DYNAMIC_AT_C_LIMIT-1>::template apply<IntTypes,ValueType>(index - GIL_DYNAMIC_AT_C_LIMIT);
    00087                     case 2: return at_c_fn<GIL_DYNAMIC_AT_C_LIMIT*2,REM                 >::template apply<IntTypes,ValueType>(index - GIL_DYNAMIC_AT_C_LIMIT*2);
    00088                 };
    00089                 throw;
    00090             }
    00091         };
    00092
    00093         template <>
    00094         struct at_c_impl<3> {
    00095             template <typename IntTypes, typename ValueType> inline
    00096             static ValueType apply(std::size_t index) {
    00097                 const std::size_t SIZE=mpl::size<IntTypes>::value;
    00098                 const std::size_t REM = SIZE % GIL_DYNAMIC_AT_C_LIMIT;
    00099                 switch (index / GIL_DYNAMIC_AT_C_LIMIT) {
    00100                     case 0: return at_c_fn<0                   ,GIL_DYNAMIC_AT_C_LIMIT-1>::template apply<IntTypes,ValueType>(index);
    00101                     case 1: return at_c_fn<GIL_DYNAMIC_AT_C_LIMIT  ,GIL_DYNAMIC_AT_C_LIMIT-1>::template apply<IntTypes,ValueType>(index - GIL_DYNAMIC_AT_C_LIMIT);
    00102                     case 2: return at_c_fn<GIL_DYNAMIC_AT_C_LIMIT*2,GIL_DYNAMIC_AT_C_LIMIT-1>::template apply<IntTypes,ValueType>(index - GIL_DYNAMIC_AT_C_LIMIT*2);
    00103                     case 3: return at_c_fn<GIL_DYNAMIC_AT_C_LIMIT*3,REM                 >::template apply<IntTypes,ValueType>(index - GIL_DYNAMIC_AT_C_LIMIT*3);
    00104                 };
    00105                 throw;
    00106             }
    00107         };
    00108     }
    00109 }
    00110
    00117
    00118 template <typename IntTypes, typename ValueType> inline
    00119 ValueType at_c(std::size_t index) {
    00120     const std::size_t Size=mpl::size<IntTypes>::value;
    00121     return detail::at_c::at_c_impl<Size/GIL_DYNAMIC_AT_C_LIMIT>::template apply<IntTypes,ValueType>(index);
    00122 }
    00123
    00124 #undef GIL_AT_C_VALUE
    00125 #undef GIL_DYNAMIC_AT_C_LIMIT
    00126 #undef GIL_AT_C_LOOKUP
    00127
    00128 } }  // namespace boost::gil
    00129
    00130 #endif