119 lines
3.3 KiB
Plaintext
119 lines
3.3 KiB
Plaintext
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// Copyright (C) 2004 Arkadiy Vertleyb
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// Use, modification and distribution is subject to the Boost Software
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// License, Version 1.0. (http://www.boost.org/LICENSE_1_0.txt)
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#ifndef BOOST_TYPEOF_INT_ENCODING_HPP_INCLUDED
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#define BOOST_TYPEOF_INT_ENCODING_HPP_INCLUDED
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#include <boost/mpl/if.hpp>
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#include <boost/mpl/size_t.hpp>
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#include <boost/config.hpp>
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namespace boost { namespace type_of {
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template<class T> struct get_unsigned
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{
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typedef T type;
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};
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template<> struct get_unsigned<signed char>
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{
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typedef unsigned char type;
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};
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template<> struct get_unsigned<char>
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{
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typedef unsigned char type;
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};
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template<> struct get_unsigned<short>
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{
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typedef unsigned short type;
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};
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template<> struct get_unsigned<int>
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{
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typedef unsigned int type;
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};
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template<> struct get_unsigned<long>
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{
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typedef unsigned long type;
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};
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//////////////////////////
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template<std::size_t n, bool Overflow>
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struct pack
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{
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BOOST_STATIC_CONSTANT(std::size_t , value=((n + 1) * 2 + (Overflow ? 1 : 0)));
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};
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template<std::size_t m>
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struct unpack
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{
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BOOST_STATIC_CONSTANT(std::size_t, value = (m / 2) - 1);
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BOOST_STATIC_CONSTANT(std::size_t, overflow = (m % 2 == 1));
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};
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////////////////////////////////
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template<class V, std::size_t n, bool overflow = (n >= 0x3fffffff)>
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struct encode_size_t : push_back<
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V,
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boost::mpl::size_t<pack<n, false>::value>
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>
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{};
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template<class V, std::size_t n>
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struct encode_size_t<V, n, true> : push_back<typename push_back<
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V,
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boost::mpl::size_t<pack<n % 0x3ffffffe, true>::value> >::type,
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boost::mpl::size_t<n / 0x3ffffffe>
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>
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{};
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template<class V, class T, T n>
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struct encode_integral : encode_size_t< V, (typename get_unsigned<T>::type)n,(((typename get_unsigned<T>::type)n)>=0x3fffffff) >
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{};
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template<class V, bool b>
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struct encode_integral<V, bool, b> : encode_size_t< V, b?1:0, false>
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{};
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///////////////////////////
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template<std::size_t n, class Iter, bool overflow>
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struct decode_size_t;
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template<std::size_t n, class Iter>
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struct decode_size_t<n, Iter, false>
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{
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BOOST_STATIC_CONSTANT(std::size_t,value = n);
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typedef Iter iter;
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};
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template<std::size_t n, class Iter>
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struct decode_size_t<n, Iter, true>
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{
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BOOST_STATIC_CONSTANT(std::size_t,m = Iter::type::value);
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BOOST_STATIC_CONSTANT(std::size_t,value = (std::size_t)m * 0x3ffffffe + n);
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typedef typename Iter::next iter;
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};
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template<class T, class Iter>
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struct decode_integral
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{
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typedef decode_integral<T,Iter> self_t;
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BOOST_STATIC_CONSTANT(std::size_t,m = Iter::type::value);
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BOOST_STATIC_CONSTANT(std::size_t,n = unpack<m>::value);
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BOOST_STATIC_CONSTANT(std::size_t,overflow = unpack<m>::overflow);
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typedef typename Iter::next nextpos;
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static const T value = (T)(std::size_t)decode_size_t<n, nextpos, overflow>::value;
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typedef typename decode_size_t<self_t::n, nextpos, self_t::overflow>::iter iter;
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};
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}}//namespace
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#endif//BOOST_TYPEOF_INT_ENCODING_HPP_INCLUDED
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