//
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// Copyright 2005-2007 Adobe Systems Incorporated
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//
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// Distributed under the Boost Software License, Version 1.0
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// See accompanying file LICENSE_1_0.txt or copy at
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// http://www.boost.org/LICENSE_1_0.txt
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//
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#ifndef BOOST_GIL_EXTENSION_DYNAMIC_IMAGE_DYNAMIC_AT_C_HPP
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#define BOOST_GIL_EXTENSION_DYNAMIC_IMAGE_DYNAMIC_AT_C_HPP
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#include <boost/gil/detail/mp11.hpp>
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#include <boost/preprocessor/facilities/empty.hpp>
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#include <boost/preprocessor/repetition/repeat.hpp>
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#include <stdexcept>
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namespace boost { namespace gil {
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// Constructs for static-to-dynamic integer convesion
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#define BOOST_GIL_AT_C_VALUE(z, N, text) mp11::mp_at_c<IntTypes, S+N>::value,
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#define BOOST_GIL_DYNAMIC_AT_C_LIMIT 226 // size of the maximum vector to handle
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#define BOOST_GIL_AT_C_LOOKUP(z, NUM, text) \
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template<std::size_t S> \
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struct at_c_fn<S,NUM> { \
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template <typename IntTypes, typename ValueType> inline \
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static ValueType apply(std::size_t index) { \
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static ValueType table[] = { \
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BOOST_PP_REPEAT(NUM, BOOST_GIL_AT_C_VALUE, BOOST_PP_EMPTY) \
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}; \
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return table[index]; \
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} \
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};
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namespace detail {
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namespace at_c {
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template <std::size_t START, std::size_t NUM> struct at_c_fn;
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BOOST_PP_REPEAT(BOOST_GIL_DYNAMIC_AT_C_LIMIT, BOOST_GIL_AT_C_LOOKUP, BOOST_PP_EMPTY)
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template <std::size_t QUOT> struct at_c_impl;
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template <>
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struct at_c_impl<0> {
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template <typename IntTypes, typename ValueType> inline
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static ValueType apply(std::size_t index) {
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return at_c_fn<0, mp11::mp_size<IntTypes>::value>::template apply<IntTypes,ValueType>(index);
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}
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};
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template <>
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struct at_c_impl<1> {
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template <typename IntTypes, typename ValueType> inline
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static ValueType apply(std::size_t index) {
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const std::size_t SIZE = mp11::mp_size<IntTypes>::value;
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const std::size_t REM = SIZE % BOOST_GIL_DYNAMIC_AT_C_LIMIT;
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switch (index / BOOST_GIL_DYNAMIC_AT_C_LIMIT) {
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case 0: return at_c_fn<0 ,BOOST_GIL_DYNAMIC_AT_C_LIMIT-1>::template apply<IntTypes,ValueType>(index);
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case 1: return at_c_fn<BOOST_GIL_DYNAMIC_AT_C_LIMIT ,REM >::template apply<IntTypes,ValueType>(index - BOOST_GIL_DYNAMIC_AT_C_LIMIT);
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};
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throw;
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}
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};
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template <>
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struct at_c_impl<2> {
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template <typename IntTypes, typename ValueType> inline
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static ValueType apply(std::size_t index) {
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const std::size_t SIZE = mp11::mp_size<IntTypes>::value;
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const std::size_t REM = SIZE % BOOST_GIL_DYNAMIC_AT_C_LIMIT;
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switch (index / BOOST_GIL_DYNAMIC_AT_C_LIMIT) {
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case 0: return at_c_fn<0 ,BOOST_GIL_DYNAMIC_AT_C_LIMIT-1>::template apply<IntTypes,ValueType>(index);
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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);
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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);
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};
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throw;
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}
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};
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template <>
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struct at_c_impl<3> {
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template <typename IntTypes, typename ValueType> inline
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static ValueType apply(std::size_t index) {
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const std::size_t SIZE = mp11::mp_size<IntTypes>::value;
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const std::size_t REM = SIZE % BOOST_GIL_DYNAMIC_AT_C_LIMIT;
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switch (index / BOOST_GIL_DYNAMIC_AT_C_LIMIT) {
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case 0: return at_c_fn<0 ,BOOST_GIL_DYNAMIC_AT_C_LIMIT-1>::template apply<IntTypes,ValueType>(index);
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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);
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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);
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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);
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};
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throw;
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}
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};
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}
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}
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////////////////////////////////////////////////////////////////////////////////////
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///
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/// \brief Given an Boost.MP11-compatible list and a dynamic index n,
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/// returns the value of the n-th element.
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/// It constructs a lookup table at compile time.
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///
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////////////////////////////////////////////////////////////////////////////////////
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template <typename IntTypes, typename ValueType> inline
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ValueType at_c(std::size_t index) {
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const std::size_t Size=mp11::mp_size<IntTypes>::value;
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return detail::at_c::at_c_impl<Size/BOOST_GIL_DYNAMIC_AT_C_LIMIT>::template apply<IntTypes,ValueType>(index);
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}
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#undef BOOST_GIL_AT_C_VALUE
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#undef BOOST_GIL_DYNAMIC_AT_C_LIMIT
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#undef BOOST_GIL_AT_C_LOOKUP
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}} // namespace boost::gil
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#endif
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