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/mpl/if.hpp>
12#include <boost/preprocessor/list/for_each_i.hpp>
13#include <boost/preprocessor/tuple/to_list.hpp>
14#include <boost/preprocessor/cat.hpp>
15#include <boost/preprocessor/list/transform.hpp>
16#include <boost/preprocessor/list/append.hpp>
17#include <boost/type_traits/alignment_of.hpp>
18#include <boost/type_traits/is_pod.hpp>
19#include <boost/static_assert.hpp>
20#include <boost/config.hpp>
21
22// should be the last #include
23#include <boost/type_traits/detail/bool_trait_def.hpp>
24
25#include <cstddef>
26
27#ifdef BOOST_MSVC
28# pragma warning(push)
29# pragma warning(disable: 4121) // alignment is sensitive to packing
30#endif
31
32namespace boost {
33
34#ifndef __BORLANDC__
35
36namespace detail {
37
38class alignment_dummy;
39typedef void (*function_ptr)();
40typedef int (alignment_dummy::*member_ptr);
41typedef int (alignment_dummy::*member_function_ptr)();
42
43#ifdef BOOST_HAS_LONG_LONG
44#define BOOST_TT_ALIGNMENT_BASE_TYPES BOOST_PP_TUPLE_TO_LIST( \
45 12, ( \
46 char, short, int, long, ::boost::long_long_type, float, double, long double \
47 , void*, function_ptr, member_ptr, member_function_ptr))
48#else
49#define BOOST_TT_ALIGNMENT_BASE_TYPES BOOST_PP_TUPLE_TO_LIST( \
50 11, ( \
51 char, short, int, long, float, double, long double \
52 , void*, function_ptr, member_ptr, member_function_ptr))
53#endif
54
55#define BOOST_TT_HAS_ONE_T(D,Data,T) boost::detail::has_one_T< T >
56
57#define BOOST_TT_ALIGNMENT_STRUCT_TYPES \
58 BOOST_PP_LIST_TRANSFORM(BOOST_TT_HAS_ONE_T, \
59 X, \
60 BOOST_TT_ALIGNMENT_BASE_TYPES)
61
62#define BOOST_TT_ALIGNMENT_TYPES \
63 BOOST_PP_LIST_APPEND(BOOST_TT_ALIGNMENT_BASE_TYPES, \
64 BOOST_TT_ALIGNMENT_STRUCT_TYPES)
65
66//
67// lower_alignment_helper --
68//
69// This template gets instantiated a lot, so use partial
70// specialization when available to reduce the compiler burden.
71//
72template <bool found, std::size_t target, class TestType>
73struct lower_alignment_helper
74{
75 typedef char type;
76 enum { value = true };
77};
78
79template <std::size_t target, class TestType>
80struct lower_alignment_helper<false,target,TestType>
81{
82 enum { value = (alignment_of<TestType>::value == target) };
83 typedef typename mpl::if_c<value, TestType, char>::type type;
84};
85
86#define BOOST_TT_CHOOSE_MIN_ALIGNMENT(R,P,I,T) \
87 typename lower_alignment_helper< \
88 BOOST_PP_CAT(found,I),target,T \
89 >::type BOOST_PP_CAT(t,I); \
90 enum { \
91 BOOST_PP_CAT(found,BOOST_PP_INC(I)) \
92 = lower_alignment_helper<BOOST_PP_CAT(found,I),target,T >::value \
93 };
94
95#define BOOST_TT_CHOOSE_T(R,P,I,T) T BOOST_PP_CAT(t,I);
96
97template <typename T>
98struct has_one_T
99{
100 T data;
101};
102
103template <std::size_t target>
104union lower_alignment
105{
106 enum { found0 = false };
107
108 BOOST_PP_LIST_FOR_EACH_I(
109 BOOST_TT_CHOOSE_MIN_ALIGNMENT
110 , ignored
111 , BOOST_TT_ALIGNMENT_TYPES
112 )
113};
114
115union max_align
116{
117 BOOST_PP_LIST_FOR_EACH_I(
118 BOOST_TT_CHOOSE_T
119 , ignored
120 , BOOST_TT_ALIGNMENT_TYPES
121 )
122};
123
124#undef BOOST_TT_ALIGNMENT_BASE_TYPES
125#undef BOOST_TT_HAS_ONE_T
126#undef BOOST_TT_ALIGNMENT_STRUCT_TYPES
127#undef BOOST_TT_ALIGNMENT_TYPES
128#undef BOOST_TT_CHOOSE_MIN_ALIGNMENT
129#undef BOOST_TT_CHOOSE_T
130
131template<std::size_t TAlign, std::size_t Align>
132struct is_aligned
133{
134 BOOST_STATIC_CONSTANT(bool,
135 value = (TAlign >= Align) & (TAlign % Align == 0)
136 );
137};
138
139
140} // namespace detail
141
142template<std::size_t Align>
143struct is_pod< ::boost::detail::lower_alignment<Align> >
144{
145 BOOST_STATIC_CONSTANT(std::size_t, value = true);
146};
147
148// This alignment method originally due to Brian Parker, implemented by David
149// Abrahams, and then ported here by Doug Gregor.
150namespace detail{
151
152template <std::size_t Align>
153class type_with_alignment_imp
154{
155 typedef ::boost::detail::lower_alignment<Align> t1;
156 typedef typename mpl::if_c<
157 ::boost::detail::is_aligned< ::boost::alignment_of<t1>::value,Align >::value
158 , t1
159 , ::boost::detail::max_align
160 >::type align_t;
161
162 BOOST_STATIC_CONSTANT(std::size_t, found = alignment_of<align_t>::value);
163
164 BOOST_STATIC_ASSERT(found >= Align);
165 BOOST_STATIC_ASSERT(found % Align == 0);
166
167 public:
168 typedef align_t type;
169};
170
171}
172
173template <std::size_t Align>
174class type_with_alignment
175 : public ::boost::detail::type_with_alignment_imp<Align>
176{
177};
178
179#if defined(__GNUC__) || (defined (__SUNPRO_CC) && (__SUNPRO_CC >= 0x5130))
180namespace tt_align_ns {
181struct __attribute__((__aligned__(2))) a2 {};
182struct __attribute__((__aligned__(4))) a4 {};
183struct __attribute__((__aligned__(8))) a8 {};
184struct __attribute__((__aligned__(16))) a16 {};
185struct __attribute__((__aligned__(32))) a32 {};
186struct __attribute__((__aligned__(64))) a64 {};
187struct __attribute__((__aligned__(128))) a128 {};
188}
189
190template<> class type_with_alignment<1> { public: typedef char type; };
191template<> class type_with_alignment<2> { public: typedef tt_align_ns::a2 type; };
192template<> class type_with_alignment<4> { public: typedef tt_align_ns::a4 type; };
193template<> class type_with_alignment<8> { public: typedef tt_align_ns::a8 type; };
194template<> class type_with_alignment<16> { public: typedef tt_align_ns::a16 type; };
195template<> class type_with_alignment<32> { public: typedef tt_align_ns::a32 type; };
196template<> class type_with_alignment<64> { public: typedef tt_align_ns::a64 type; };
197template<> class type_with_alignment<128> { public: typedef tt_align_ns::a128 type; };
198
199namespace detail {
200BOOST_TT_AUX_BOOL_TRAIT_IMPL_SPEC1(is_pod,::boost::tt_align_ns::a2,true)
201BOOST_TT_AUX_BOOL_TRAIT_IMPL_SPEC1(is_pod,::boost::tt_align_ns::a4,true)
202BOOST_TT_AUX_BOOL_TRAIT_IMPL_SPEC1(is_pod,::boost::tt_align_ns::a8,true)
203BOOST_TT_AUX_BOOL_TRAIT_IMPL_SPEC1(is_pod,::boost::tt_align_ns::a16,true)
204BOOST_TT_AUX_BOOL_TRAIT_IMPL_SPEC1(is_pod,::boost::tt_align_ns::a32,true)
205BOOST_TT_AUX_BOOL_TRAIT_IMPL_SPEC1(is_pod,::boost::tt_align_ns::a64,true)
206BOOST_TT_AUX_BOOL_TRAIT_IMPL_SPEC1(is_pod,::boost::tt_align_ns::a128,true)
207}
208#endif
209#if defined(BOOST_MSVC) || (defined(BOOST_INTEL) && defined(_MSC_VER))
210//
211// MSVC supports types which have alignments greater than the normal
212// maximum: these are used for example in the types __m64 and __m128
213// to provide types with alignment requirements which match the SSE
214// registers. Therefore we extend type_with_alignment<> to support
215// such types, however, we have to be careful to use a builtin type
216// whenever possible otherwise we break previously working code:
217// see http://article.gmane.org/gmane.comp.lib.boost.devel/173011
218// for an example and test case. Thus types like a8 below will
219// be used *only* if the existing implementation can't provide a type
220// with suitable alignment. This does mean however, that type_with_alignment<>
221// may return a type which cannot be passed through a function call
222// by value (and neither can any type containing such a type like
223// Boost.Optional). However, this only happens when we have no choice
224// in the matter because no other "ordinary" type is available.
225//
226namespace tt_align_ns {
227struct __declspec(align(8)) a8 {
228 char m[8];
229 typedef a8 type;
230};
231struct __declspec(align(16)) a16 {
232 char m[16];
233 typedef a16 type;
234};
235struct __declspec(align(32)) a32 {
236 char m[32];
237 typedef a32 type;
238};
239struct __declspec(align(64)) a64
240{
241 char m[64];
242 typedef a64 type;
243};
244struct __declspec(align(128)) a128 {
245 char m[128];
246 typedef a128 type;
247};
248}
249
250template<> class type_with_alignment<8>
251{
252 typedef mpl::if_c<
253 ::boost::alignment_of<boost::detail::max_align>::value < 8,
254 tt_align_ns::a8,
255 boost::detail::type_with_alignment_imp<8> >::type t1;
256public:
257 typedef t1::type type;
258};
259template<> class type_with_alignment<16>
260{
261 typedef mpl::if_c<
262 ::boost::alignment_of<boost::detail::max_align>::value < 16,
263 tt_align_ns::a16,
264 boost::detail::type_with_alignment_imp<16> >::type t1;
265public:
266 typedef t1::type type;
267};
268template<> class type_with_alignment<32>
269{
270 typedef mpl::if_c<
271 ::boost::alignment_of<boost::detail::max_align>::value < 32,
272 tt_align_ns::a32,
273 boost::detail::type_with_alignment_imp<32> >::type t1;
274public:
275 typedef t1::type type;
276};
277template<> class type_with_alignment<64> {
278 typedef mpl::if_c<
279 ::boost::alignment_of<boost::detail::max_align>::value < 64,
280 tt_align_ns::a64,
281 boost::detail::type_with_alignment_imp<64> >::type t1;
282public:
283 typedef t1::type type;
284};
285template<> class type_with_alignment<128> {
286 typedef mpl::if_c<
287 ::boost::alignment_of<boost::detail::max_align>::value < 128,
288 tt_align_ns::a128,
289 boost::detail::type_with_alignment_imp<128> >::type t1;
290public:
291 typedef t1::type type;
292};
293
294namespace detail {
295BOOST_TT_AUX_BOOL_TRAIT_IMPL_SPEC1(is_pod,::boost::tt_align_ns::a8,true)
296BOOST_TT_AUX_BOOL_TRAIT_IMPL_SPEC1(is_pod,::boost::tt_align_ns::a16,true)
297BOOST_TT_AUX_BOOL_TRAIT_IMPL_SPEC1(is_pod,::boost::tt_align_ns::a32,true)
298BOOST_TT_AUX_BOOL_TRAIT_IMPL_SPEC1(is_pod,::boost::tt_align_ns::a64,true)
299BOOST_TT_AUX_BOOL_TRAIT_IMPL_SPEC1(is_pod,::boost::tt_align_ns::a128,true)
300}
301#endif
302
303#else
304
305//
306// Borland specific version, we have this for two reasons:
307// 1) The version above doesn't always compile (with the new test cases for example)
308// 2) Because of Borlands #pragma option we can create types with alignments that are
309// greater that the largest aligned builtin type.
310
311namespace tt_align_ns{
312#pragma option push -a16
313struct a2{ short s; };
314struct a4{ int s; };
315struct a8{ double s; };
316struct a16{ long double s; };
317#pragma option pop
318}
319
320namespace detail {
321
322typedef ::boost::tt_align_ns::a16 max_align;
323
324//#if ! BOOST_WORKAROUND(__CODEGEARC__, BOOST_TESTED_AT(0x610))
325BOOST_TT_AUX_BOOL_TRAIT_IMPL_SPEC1(is_pod,::boost::tt_align_ns::a2,true)
326BOOST_TT_AUX_BOOL_TRAIT_IMPL_SPEC1(is_pod,::boost::tt_align_ns::a4,true)
327BOOST_TT_AUX_BOOL_TRAIT_IMPL_SPEC1(is_pod,::boost::tt_align_ns::a8,true)
328BOOST_TT_AUX_BOOL_TRAIT_IMPL_SPEC1(is_pod,::boost::tt_align_ns::a16,true)
329//#endif
330}
331
332template <std::size_t N> struct type_with_alignment
333{
334 // We should never get to here, but if we do use the maximally
335 // aligned type:
336 // BOOST_STATIC_ASSERT(0);
337 typedef tt_align_ns::a16 type;
338};
339template <> struct type_with_alignment<1>{ typedef char type; };
340template <> struct type_with_alignment<2>{ typedef tt_align_ns::a2 type; };
341template <> struct type_with_alignment<4>{ typedef tt_align_ns::a4 type; };
342template <> struct type_with_alignment<8>{ typedef tt_align_ns::a8 type; };
343template <> struct type_with_alignment<16>{ typedef tt_align_ns::a16 type; };
344
345#endif
346
347} // namespace boost
348
349#ifdef BOOST_MSVC
350# pragma warning(pop)
351#endif
352
353#include <boost/type_traits/detail/bool_trait_undef.hpp>
354
355#endif // BOOST_TT_TYPE_WITH_ALIGNMENT_INCLUDED
356
357
358