1// (C) Copyright John Maddock 2000.
2// Use, modification and distribution are subject to the Boost Software License,
3// Version 1.0. (See accompanying file LICENSE_1_0.txt or copy at
4// http://www.boost.org/LICENSE_1_0.txt).
5//
6// See http://www.boost.org/libs/type_traits for most recent version including documentation.
7
8#ifndef BOOST_TT_TYPE_WITH_ALIGNMENT_INCLUDED
9#define BOOST_TT_TYPE_WITH_ALIGNMENT_INCLUDED
10
11#include <boost/type_traits/alignment_of.hpp>
12#include <boost/type_traits/is_pod.hpp>
13#include <boost/static_assert.hpp>
14#include <boost/config.hpp>
15#include <cstddef>
16#include <boost/detail/workaround.hpp>
17
18#ifdef BOOST_MSVC
19# pragma warning(push)
20# pragma warning(disable: 4121) // alignment is sensitive to packing
21#endif
22
23#ifdef _MSC_VER
24#include <boost/type_traits/conditional.hpp>
25#endif
26
27namespace boost {
28 namespace detail{
29
30#ifndef __BORLANDC__
31
32 union max_align
33 {
34 char c;
35 short s;
36 int i;
37 long l;
38#ifndef BOOST_NO_LONG_LONG
39 boost::long_long_type ll;
40#endif
41#ifdef BOOST_HAS_INT128
42 boost::int128_type i128;
43#endif
44 float f;
45 double d;
46 long double ld;
47#ifdef BOOST_HAS_FLOAT128
48 __float128 f128;
49#endif
50 };
51
52template <std::size_t Target, bool check> struct long_double_alignment{ typedef long double type; };
53template <std::size_t Target> struct long_double_alignment<Target, false>{ typedef boost::detail::max_align type; };
54
55template <std::size_t Target, bool check> struct double_alignment{ typedef double type; };
56template <std::size_t Target> struct double_alignment<Target, false>{ typedef typename long_double_alignment<Target, boost::alignment_of<long double>::value >= Target>::type type; };
57
58#ifndef BOOST_NO_LONG_LONG
59template <std::size_t Target, bool check> struct long_long_alignment{ typedef boost::long_long_type type; };
60template <std::size_t Target> struct long_long_alignment<Target, false>{ typedef typename double_alignment<Target, boost::alignment_of<double>::value >= Target>::type type; };
61#endif
62
63template <std::size_t Target, bool check> struct long_alignment{ typedef long type; };
64#ifndef BOOST_NO_LONG_LONG
65template <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; };
66#else
67template <std::size_t Target> struct long_alignment<Target, false>{ typedef typename double_alignment<Target, boost::alignment_of<double>::value >= Target>::type type; };
68#endif
69
70template <std::size_t Target, bool check> struct int_alignment{ typedef int type; };
71template <std::size_t Target> struct int_alignment<Target, false>{ typedef typename long_alignment<Target, boost::alignment_of<long>::value >= Target>::type type; };
72
73template <std::size_t Target, bool check> struct short_alignment{ typedef short type; };
74template <std::size_t Target> struct short_alignment<Target, false>{ typedef typename int_alignment<Target, boost::alignment_of<int>::value >= Target>::type type; };
75
76template <std::size_t Target, bool check> struct char_alignment{ typedef char type; };
77template <std::size_t Target> struct char_alignment<Target, false>{ typedef typename short_alignment<Target, boost::alignment_of<short>::value >= Target>::type type; };
78
79}
80
81template <std::size_t Align>
82struct type_with_alignment
83{
84 typedef typename boost::detail::char_alignment<Align, boost::alignment_of<char>::value >= Align>::type type;
85};
86
87#if (defined(__GNUC__) || (defined (__SUNPRO_CC) && (__SUNPRO_CC >= 0x5130)) || defined(__clang__)) && !defined(BOOST_TT_DISABLE_INTRINSICS)
88namespace tt_align_ns {
89struct __attribute__((__aligned__(2))) a2 {};
90struct __attribute__((__aligned__(4))) a4 {};
91struct __attribute__((__aligned__(8))) a8 {};
92struct __attribute__((__aligned__(16))) a16 {};
93struct __attribute__((__aligned__(32))) a32 {};
94struct __attribute__((__aligned__(64))) a64 {};
95struct __attribute__((__aligned__(128))) a128 {};
96}
97
98template<> struct type_with_alignment<1> { public: typedef char type; };
99template<> struct type_with_alignment<2> { public: typedef tt_align_ns::a2 type; };
100template<> struct type_with_alignment<4> { public: typedef tt_align_ns::a4 type; };
101template<> struct type_with_alignment<8> { public: typedef tt_align_ns::a8 type; };
102template<> struct type_with_alignment<16> { public: typedef tt_align_ns::a16 type; };
103template<> struct type_with_alignment<32> { public: typedef tt_align_ns::a32 type; };
104template<> struct type_with_alignment<64> { public: typedef tt_align_ns::a64 type; };
105template<> struct type_with_alignment<128> { public: typedef tt_align_ns::a128 type; };
106
107template<> struct is_pod< ::boost::tt_align_ns::a2> : public true_type{};
108template<> struct is_pod< ::boost::tt_align_ns::a4> : public true_type{};
109template<> struct is_pod< ::boost::tt_align_ns::a8> : public true_type{};
110template<> struct is_pod< ::boost::tt_align_ns::a16> : public true_type{};
111template<> struct is_pod< ::boost::tt_align_ns::a32> : public true_type{};
112template<> struct is_pod< ::boost::tt_align_ns::a64> : public true_type{};
113template<> struct is_pod< ::boost::tt_align_ns::a128> : public true_type{};
114
115#endif
116#if (defined(BOOST_MSVC) || (defined(BOOST_INTEL) && defined(_MSC_VER))) && !defined(BOOST_TT_DISABLE_INTRINSICS)
117//
118// MSVC supports types which have alignments greater than the normal
119// maximum: these are used for example in the types __m64 and __m128
120// to provide types with alignment requirements which match the SSE
121// registers. Therefore we extend type_with_alignment<> to support
122// such types, however, we have to be careful to use a builtin type
123// whenever possible otherwise we break previously working code:
124// see http://article.gmane.org/gmane.comp.lib.boost.devel/173011
125// for an example and test case. Thus types like a8 below will
126// be used *only* if the existing implementation can't provide a type
127// with suitable alignment. This does mean however, that type_with_alignment<>
128// may return a type which cannot be passed through a function call
129// by value (and neither can any type containing such a type like
130// Boost.Optional). However, this only happens when we have no choice
131// in the matter because no other "ordinary" type is available.
132//
133namespace tt_align_ns {
134struct __declspec(align(8)) a8 {
135 char m[8];
136 typedef a8 type;
137};
138struct __declspec(align(16)) a16 {
139 char m[16];
140 typedef a16 type;
141};
142struct __declspec(align(32)) a32 {
143 char m[32];
144 typedef a32 type;
145};
146struct __declspec(align(64)) a64
147{
148 char m[64];
149 typedef a64 type;
150};
151struct __declspec(align(128)) a128 {
152 char m[128];
153 typedef a128 type;
154};
155}
156
157template<> struct type_with_alignment<8>
158{
159 typedef boost::conditional<
160 ::boost::alignment_of<boost::detail::max_align>::value < 8,
161 tt_align_ns::a8,
162 boost::detail::char_alignment<8, false> >::type t1;
163public:
164 typedef t1::type type;
165};
166template<> struct type_with_alignment<16>
167{
168 typedef boost::conditional<
169 ::boost::alignment_of<boost::detail::max_align>::value < 16,
170 tt_align_ns::a16,
171 boost::detail::char_alignment<16, false> >::type t1;
172public:
173 typedef t1::type type;
174};
175template<> struct type_with_alignment<32>
176{
177 typedef boost::conditional<
178 ::boost::alignment_of<boost::detail::max_align>::value < 32,
179 tt_align_ns::a32,
180 boost::detail::char_alignment<32, false> >::type t1;
181public:
182 typedef t1::type type;
183};
184template<> struct type_with_alignment<64> {
185 typedef boost::conditional<
186 ::boost::alignment_of<boost::detail::max_align>::value < 64,
187 tt_align_ns::a64,
188 boost::detail::char_alignment<64, false> >::type t1;
189public:
190 typedef t1::type type;
191};
192template<> struct type_with_alignment<128> {
193 typedef boost::conditional<
194 ::boost::alignment_of<boost::detail::max_align>::value < 128,
195 tt_align_ns::a128,
196 boost::detail::char_alignment<128, false> >::type t1;
197public:
198 typedef t1::type type;
199};
200
201template<> struct is_pod< ::boost::tt_align_ns::a8> : public true_type{};
202template<> struct is_pod< ::boost::tt_align_ns::a16> : public true_type{};
203template<> struct is_pod< ::boost::tt_align_ns::a32> : public true_type{};
204template<> struct is_pod< ::boost::tt_align_ns::a64> : public true_type{};
205template<> struct is_pod< ::boost::tt_align_ns::a128> : public true_type{};
206
207#endif
208
209#else
210
211//
212// Borland specific version, we have this for two reasons:
213// 1) The version above doesn't always compile (with the new test cases for example)
214// 2) Because of Borlands #pragma option we can create types with alignments that are
215// greater that the largest aligned builtin type.
216
217namespace tt_align_ns{
218#pragma option push -a16
219struct a2{ short s; };
220struct a4{ int s; };
221struct a8{ double s; };
222struct a16{ long double s; };
223#pragma option pop
224}
225
226namespace detail {
227
228typedef ::boost::tt_align_ns::a16 max_align;
229
230}
231//#if ! BOOST_WORKAROUND(__CODEGEARC__, BOOST_TESTED_AT(0x610))
232template <> struct is_pod< ::boost::tt_align_ns::a2> : public true_type{};
233template <> struct is_pod< ::boost::tt_align_ns::a4> : public true_type{};
234template <> struct is_pod< ::boost::tt_align_ns::a8> : public true_type{};
235template <> struct is_pod< ::boost::tt_align_ns::a16> : public true_type{};
236//#endif
237
238template <std::size_t N> struct type_with_alignment
239{
240 // We should never get to here, but if we do use the maximally
241 // aligned type:
242 // BOOST_STATIC_ASSERT(0);
243 typedef tt_align_ns::a16 type;
244};
245template <> struct type_with_alignment<1>{ typedef char type; };
246template <> struct type_with_alignment<2>{ typedef tt_align_ns::a2 type; };
247template <> struct type_with_alignment<4>{ typedef tt_align_ns::a4 type; };
248template <> struct type_with_alignment<8>{ typedef tt_align_ns::a8 type; };
249template <> struct type_with_alignment<16>{ typedef tt_align_ns::a16 type; };
250
251#endif
252
253} // namespace boost
254
255#ifdef BOOST_MSVC
256# pragma warning(pop)
257#endif
258
259#endif // BOOST_TT_TYPE_WITH_ALIGNMENT_INCLUDED
260
261
262