262 lines
10 KiB
Plaintext
262 lines
10 KiB
Plaintext
// (C) Copyright John Maddock 2000.
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// Use, modification and distribution are subject to the Boost Software License,
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// Version 1.0. (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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// See http://www.boost.org/libs/type_traits for most recent version including documentation.
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#ifndef BOOST_TT_TYPE_WITH_ALIGNMENT_INCLUDED
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#define BOOST_TT_TYPE_WITH_ALIGNMENT_INCLUDED
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#include <boost/type_traits/alignment_of.hpp>
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#include <boost/type_traits/is_pod.hpp>
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#include <boost/static_assert.hpp>
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#include <boost/config.hpp>
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#include <cstddef> // size_t
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#include <boost/detail/workaround.hpp>
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#ifdef BOOST_MSVC
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# pragma warning(push)
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# pragma warning(disable: 4121) // alignment is sensitive to packing
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#endif
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#ifdef _MSC_VER
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#include <boost/type_traits/conditional.hpp>
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#endif
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namespace boost {
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namespace detail{
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#ifndef __BORLANDC__
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union max_align
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{
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char c;
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short s;
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int i;
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long l;
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#ifndef BOOST_NO_LONG_LONG
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boost::long_long_type ll;
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#endif
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#ifdef BOOST_HAS_INT128
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boost::int128_type i128;
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#endif
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float f;
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double d;
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long double ld;
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#ifdef BOOST_HAS_FLOAT128
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__float128 f128;
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#endif
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};
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template <std::size_t Target, bool check> struct long_double_alignment{ typedef long double type; };
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template <std::size_t Target> struct long_double_alignment<Target, false>{ typedef boost::detail::max_align type; };
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template <std::size_t Target, bool check> struct double_alignment{ typedef double type; };
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template <std::size_t Target> struct double_alignment<Target, false>{ typedef typename long_double_alignment<Target, boost::alignment_of<long double>::value >= Target>::type type; };
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#ifndef BOOST_NO_LONG_LONG
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template <std::size_t Target, bool check> struct long_long_alignment{ typedef boost::long_long_type type; };
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template <std::size_t Target> struct long_long_alignment<Target, false>{ typedef typename double_alignment<Target, boost::alignment_of<double>::value >= Target>::type type; };
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#endif
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template <std::size_t Target, bool check> struct long_alignment{ typedef long type; };
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#ifndef BOOST_NO_LONG_LONG
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template <std::size_t Target> struct long_alignment<Target, false>{ typedef typename long_long_alignment<Target, boost::alignment_of<boost::long_long_type>::value >= Target>::type type; };
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#else
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template <std::size_t Target> struct long_alignment<Target, false>{ typedef typename double_alignment<Target, boost::alignment_of<double>::value >= Target>::type type; };
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#endif
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template <std::size_t Target, bool check> struct int_alignment{ typedef int type; };
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template <std::size_t Target> struct int_alignment<Target, false>{ typedef typename long_alignment<Target, boost::alignment_of<long>::value >= Target>::type type; };
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template <std::size_t Target, bool check> struct short_alignment{ typedef short type; };
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template <std::size_t Target> struct short_alignment<Target, false>{ typedef typename int_alignment<Target, boost::alignment_of<int>::value >= Target>::type type; };
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template <std::size_t Target, bool check> struct char_alignment{ typedef char type; };
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template <std::size_t Target> struct char_alignment<Target, false>{ typedef typename short_alignment<Target, boost::alignment_of<short>::value >= Target>::type type; };
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}
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template <std::size_t Align>
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struct type_with_alignment
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{
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typedef typename boost::detail::char_alignment<Align, boost::alignment_of<char>::value >= Align>::type type;
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};
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#if (defined(__GNUC__) || (defined (__SUNPRO_CC) && (__SUNPRO_CC >= 0x5130)) || defined(__clang__)) && !defined(BOOST_TT_DISABLE_INTRINSICS)
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namespace tt_align_ns {
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struct __attribute__((__aligned__(2))) a2 {};
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struct __attribute__((__aligned__(4))) a4 {};
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struct __attribute__((__aligned__(8))) a8 {};
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struct __attribute__((__aligned__(16))) a16 {};
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struct __attribute__((__aligned__(32))) a32 {};
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struct __attribute__((__aligned__(64))) a64 {};
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struct __attribute__((__aligned__(128))) a128 {};
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}
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template<> struct type_with_alignment<1> { public: typedef char type; };
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template<> struct type_with_alignment<2> { public: typedef tt_align_ns::a2 type; };
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template<> struct type_with_alignment<4> { public: typedef tt_align_ns::a4 type; };
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template<> struct type_with_alignment<8> { public: typedef tt_align_ns::a8 type; };
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template<> struct type_with_alignment<16> { public: typedef tt_align_ns::a16 type; };
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template<> struct type_with_alignment<32> { public: typedef tt_align_ns::a32 type; };
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template<> struct type_with_alignment<64> { public: typedef tt_align_ns::a64 type; };
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template<> struct type_with_alignment<128> { public: typedef tt_align_ns::a128 type; };
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template<> struct is_pod< ::boost::tt_align_ns::a2> : public true_type{};
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template<> struct is_pod< ::boost::tt_align_ns::a4> : public true_type{};
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template<> struct is_pod< ::boost::tt_align_ns::a8> : public true_type{};
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template<> struct is_pod< ::boost::tt_align_ns::a16> : public true_type{};
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template<> struct is_pod< ::boost::tt_align_ns::a32> : public true_type{};
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template<> struct is_pod< ::boost::tt_align_ns::a64> : public true_type{};
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template<> struct is_pod< ::boost::tt_align_ns::a128> : public true_type{};
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#endif
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#if (defined(BOOST_MSVC) || (defined(BOOST_INTEL) && defined(_MSC_VER))) && !defined(BOOST_TT_DISABLE_INTRINSICS)
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//
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// MSVC supports types which have alignments greater than the normal
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// maximum: these are used for example in the types __m64 and __m128
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// to provide types with alignment requirements which match the SSE
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// registers. Therefore we extend type_with_alignment<> to support
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// such types, however, we have to be careful to use a builtin type
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// whenever possible otherwise we break previously working code:
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// see http://article.gmane.org/gmane.comp.lib.boost.devel/173011
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// for an example and test case. Thus types like a8 below will
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// be used *only* if the existing implementation can't provide a type
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// with suitable alignment. This does mean however, that type_with_alignment<>
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// may return a type which cannot be passed through a function call
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// by value (and neither can any type containing such a type like
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// Boost.Optional). However, this only happens when we have no choice
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// in the matter because no other "ordinary" type is available.
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//
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namespace tt_align_ns {
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struct __declspec(align(8)) a8 {
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char m[8];
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typedef a8 type;
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};
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struct __declspec(align(16)) a16 {
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char m[16];
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typedef a16 type;
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};
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struct __declspec(align(32)) a32 {
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char m[32];
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typedef a32 type;
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};
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struct __declspec(align(64)) a64
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{
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char m[64];
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typedef a64 type;
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};
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struct __declspec(align(128)) a128 {
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char m[128];
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typedef a128 type;
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};
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}
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template<> struct type_with_alignment<8>
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{
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typedef boost::conditional<
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::boost::alignment_of<boost::detail::max_align>::value < 8,
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tt_align_ns::a8,
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boost::detail::char_alignment<8, false> >::type t1;
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public:
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typedef t1::type type;
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};
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template<> struct type_with_alignment<16>
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{
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typedef boost::conditional<
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::boost::alignment_of<boost::detail::max_align>::value < 16,
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tt_align_ns::a16,
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boost::detail::char_alignment<16, false> >::type t1;
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public:
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typedef t1::type type;
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};
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template<> struct type_with_alignment<32>
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{
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typedef boost::conditional<
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::boost::alignment_of<boost::detail::max_align>::value < 32,
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tt_align_ns::a32,
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boost::detail::char_alignment<32, false> >::type t1;
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public:
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typedef t1::type type;
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};
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template<> struct type_with_alignment<64> {
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typedef boost::conditional<
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::boost::alignment_of<boost::detail::max_align>::value < 64,
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tt_align_ns::a64,
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boost::detail::char_alignment<64, false> >::type t1;
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public:
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typedef t1::type type;
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};
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template<> struct type_with_alignment<128> {
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typedef boost::conditional<
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::boost::alignment_of<boost::detail::max_align>::value < 128,
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tt_align_ns::a128,
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boost::detail::char_alignment<128, false> >::type t1;
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public:
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typedef t1::type type;
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};
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template<> struct is_pod< ::boost::tt_align_ns::a8> : public true_type{};
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template<> struct is_pod< ::boost::tt_align_ns::a16> : public true_type{};
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template<> struct is_pod< ::boost::tt_align_ns::a32> : public true_type{};
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template<> struct is_pod< ::boost::tt_align_ns::a64> : public true_type{};
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template<> struct is_pod< ::boost::tt_align_ns::a128> : public true_type{};
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#endif
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#else
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//
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// Borland specific version, we have this for two reasons:
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// 1) The version above doesn't always compile (with the new test cases for example)
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// 2) Because of Borlands #pragma option we can create types with alignments that are
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// greater that the largest aligned builtin type.
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namespace tt_align_ns{
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#pragma option push -a16
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struct a2{ short s; };
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struct a4{ int s; };
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struct a8{ double s; };
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struct a16{ long double s; };
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#pragma option pop
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}
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namespace detail {
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typedef ::boost::tt_align_ns::a16 max_align;
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}
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//#if ! BOOST_WORKAROUND(__CODEGEARC__, BOOST_TESTED_AT(0x610))
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template <> struct is_pod< ::boost::tt_align_ns::a2> : public true_type{};
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template <> struct is_pod< ::boost::tt_align_ns::a4> : public true_type{};
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template <> struct is_pod< ::boost::tt_align_ns::a8> : public true_type{};
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template <> struct is_pod< ::boost::tt_align_ns::a16> : public true_type{};
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//#endif
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template <std::size_t N> struct type_with_alignment
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{
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// We should never get to here, but if we do use the maximally
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// aligned type:
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// BOOST_STATIC_ASSERT(0);
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typedef tt_align_ns::a16 type;
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};
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template <> struct type_with_alignment<1>{ typedef char type; };
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template <> struct type_with_alignment<2>{ typedef tt_align_ns::a2 type; };
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template <> struct type_with_alignment<4>{ typedef tt_align_ns::a4 type; };
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template <> struct type_with_alignment<8>{ typedef tt_align_ns::a8 type; };
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template <> struct type_with_alignment<16>{ typedef tt_align_ns::a16 type; };
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#endif
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} // namespace boost
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#ifdef BOOST_MSVC
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# pragma warning(pop)
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#endif
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#endif // BOOST_TT_TYPE_WITH_ALIGNMENT_INCLUDED
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