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1 | /* | |
2 | * Copyright (c) 1996-1997 | |
3 | * Silicon Graphics Computer Systems, Inc. | |
4 | * | |
5 | * Permission to use, copy, modify, distribute and sell this software | |
6 | * and its documentation for any purpose is hereby granted without fee, | |
7 | * provided that the above copyright notice appear in all copies and | |
8 | * that both that copyright notice and this permission notice appear | |
9 | * in supporting documentation. Silicon Graphics makes no | |
10 | * representations about the suitability of this software for any | |
11 | * purpose. It is provided "as is" without express or implied warranty. | |
12 | * | |
13 | * Copyright (c) 2002 | |
14 | * Hewlett-Packard Company | |
15 | * | |
16 | * Permission to use, copy, modify, distribute and sell this software | |
17 | * and its documentation for any purpose is hereby granted without fee, | |
18 | * provided that the above copyright notice appear in all copies and | |
19 | * that both that copyright notice and this permission notice appear | |
20 | * in supporting documentation. Hewlett-Packard Company makes no | |
21 | * representations about the suitability of this software for any | |
22 | * purpose. It is provided "as is" without express or implied warranty. | |
23 | */ | |
24 | ||
25 | /* | |
26 | * This implements standard-conforming allocators that interact with | |
27 | * the garbage collector. Gc_alloctor<T> allocates garbage-collectable | |
28 | * objects of type T. Traceable_allocator<T> allocates objects that | |
29 | * are not temselves garbage collected, but are scanned by the | |
30 | * collector for pointers to collectable objects. Traceable_alloc | |
31 | * should be used for explicitly managed STL containers that may | |
32 | * point to collectable objects. | |
33 | * | |
34 | * This code was derived from an earlier version of the GNU C++ standard | |
35 | * library, which itself was derived from the SGI STL implementation. | |
36 | */ | |
37 | ||
38 | #ifndef GC_ALLOCATOR_H | |
39 | ||
40 | #define GC_ALLOCATOR_H | |
41 | ||
42 | #include "gc.h" | |
43 | #include <new> // for placement new | |
44 | ||
45 | #if defined(__GNUC__) | |
46 | # define GC_ATTR_UNUSED __attribute__((unused)) | |
47 | #else | |
48 | # define GC_ATTR_UNUSED | |
49 | #endif | |
50 | ||
51 | /* First some helpers to allow us to dispatch on whether or not a type | |
52 | * is known to be pointerfree. | |
53 | * These are private, except that the client may invoke the | |
54 | * GC_DECLARE_PTRFREE macro. | |
55 | */ | |
56 | ||
57 | struct GC_true_type {}; | |
58 | struct GC_false_type {}; | |
59 | ||
60 | template <class GC_tp> | |
61 | struct GC_type_traits { | |
62 | GC_false_type GC_is_ptr_free; | |
63 | }; | |
64 | ||
65 | # define GC_DECLARE_PTRFREE(T) \ | |
66 | template<> struct GC_type_traits<T> { GC_true_type GC_is_ptr_free; } | |
67 | ||
68 | GC_DECLARE_PTRFREE(char); | |
69 | GC_DECLARE_PTRFREE(signed char); | |
70 | GC_DECLARE_PTRFREE(unsigned char); | |
71 | GC_DECLARE_PTRFREE(signed short); | |
72 | GC_DECLARE_PTRFREE(unsigned short); | |
73 | GC_DECLARE_PTRFREE(signed int); | |
74 | GC_DECLARE_PTRFREE(unsigned int); | |
75 | GC_DECLARE_PTRFREE(signed long); | |
76 | GC_DECLARE_PTRFREE(unsigned long); | |
77 | GC_DECLARE_PTRFREE(float); | |
78 | GC_DECLARE_PTRFREE(double); | |
79 | GC_DECLARE_PTRFREE(long double); | |
80 | /* The client may want to add others. */ | |
81 | ||
82 | // In the following GC_Tp is GC_true_type iff we are allocating a | |
83 | // pointerfree object. | |
84 | template <class GC_Tp> | |
85 | inline void * GC_selective_alloc(size_t n, GC_Tp) { | |
86 | return GC_MALLOC(n); | |
87 | } | |
88 | ||
89 | template <> | |
90 | inline void * GC_selective_alloc<GC_true_type>(size_t n, GC_true_type) { | |
91 | return GC_MALLOC_ATOMIC(n); | |
92 | } | |
93 | ||
94 | /* Now the public gc_allocator<T> class: | |
95 | */ | |
96 | template <class GC_Tp> | |
97 | class gc_allocator { | |
98 | public: | |
99 | typedef size_t size_type; | |
100 | typedef ptrdiff_t difference_type; | |
101 | typedef GC_Tp* pointer; | |
102 | typedef const GC_Tp* const_pointer; | |
103 | typedef GC_Tp& reference; | |
104 | typedef const GC_Tp& const_reference; | |
105 | typedef GC_Tp value_type; | |
106 | ||
107 | template <class GC_Tp1> struct rebind { | |
108 | typedef gc_allocator<GC_Tp1> other; | |
109 | }; | |
110 | ||
111 | gc_allocator() {} | |
112 | gc_allocator(const gc_allocator&) throw() {} | |
113 | # if !(GC_NO_MEMBER_TEMPLATES || 0 < _MSC_VER && _MSC_VER <= 1200) | |
114 | // MSVC++ 6.0 do not support member templates | |
115 | template <class GC_Tp1> gc_allocator(const gc_allocator<GC_Tp1>&) throw() {} | |
116 | # endif | |
117 | ~gc_allocator() throw() {} | |
118 | ||
119 | pointer address(reference GC_x) const { return &GC_x; } | |
120 | const_pointer address(const_reference GC_x) const { return &GC_x; } | |
121 | ||
122 | // GC_n is permitted to be 0. The C++ standard says nothing about what | |
123 | // the return value is when GC_n == 0. | |
124 | GC_Tp* allocate(size_type GC_n, const void* = 0) { | |
125 | GC_type_traits<GC_Tp> traits; | |
126 | return static_cast<GC_Tp *> | |
127 | (GC_selective_alloc(GC_n * sizeof(GC_Tp), | |
128 | traits.GC_is_ptr_free)); | |
129 | } | |
130 | ||
131 | // __p is not permitted to be a null pointer. | |
132 | void deallocate(pointer __p, size_type GC_ATTR_UNUSED GC_n) | |
133 | { GC_FREE(__p); } | |
134 | ||
135 | size_type max_size() const throw() | |
136 | { return size_t(-1) / sizeof(GC_Tp); } | |
137 | ||
138 | void construct(pointer __p, const GC_Tp& __val) { new(__p) GC_Tp(__val); } | |
139 | void destroy(pointer __p) { __p->~GC_Tp(); } | |
140 | }; | |
141 | ||
142 | template<> | |
143 | class gc_allocator<void> { | |
144 | typedef size_t size_type; | |
145 | typedef ptrdiff_t difference_type; | |
146 | typedef void* pointer; | |
147 | typedef const void* const_pointer; | |
148 | typedef void value_type; | |
149 | ||
150 | template <class GC_Tp1> struct rebind { | |
151 | typedef gc_allocator<GC_Tp1> other; | |
152 | }; | |
153 | }; | |
154 | ||
155 | ||
156 | template <class GC_T1, class GC_T2> | |
157 | inline bool operator==(const gc_allocator<GC_T1>&, const gc_allocator<GC_T2>&) | |
158 | { | |
159 | return true; | |
160 | } | |
161 | ||
162 | template <class GC_T1, class GC_T2> | |
163 | inline bool operator!=(const gc_allocator<GC_T1>&, const gc_allocator<GC_T2>&) | |
164 | { | |
165 | return false; | |
166 | } | |
167 | ||
168 | /* | |
169 | * And the public traceable_allocator class. | |
170 | */ | |
171 | ||
172 | // Note that we currently don't specialize the pointer-free case, since a | |
173 | // pointer-free traceable container doesn't make that much sense, | |
174 | // though it could become an issue due to abstraction boundaries. | |
175 | template <class GC_Tp> | |
176 | class traceable_allocator { | |
177 | public: | |
178 | typedef size_t size_type; | |
179 | typedef ptrdiff_t difference_type; | |
180 | typedef GC_Tp* pointer; | |
181 | typedef const GC_Tp* const_pointer; | |
182 | typedef GC_Tp& reference; | |
183 | typedef const GC_Tp& const_reference; | |
184 | typedef GC_Tp value_type; | |
185 | ||
186 | template <class GC_Tp1> struct rebind { | |
187 | typedef traceable_allocator<GC_Tp1> other; | |
188 | }; | |
189 | ||
190 | traceable_allocator() throw() {} | |
191 | traceable_allocator(const traceable_allocator&) throw() {} | |
192 | # if !(GC_NO_MEMBER_TEMPLATES || 0 < _MSC_VER && _MSC_VER <= 1200) | |
193 | // MSVC++ 6.0 do not support member templates | |
194 | template <class GC_Tp1> traceable_allocator | |
195 | (const traceable_allocator<GC_Tp1>&) throw() {} | |
196 | # endif | |
197 | ~traceable_allocator() throw() {} | |
198 | ||
199 | pointer address(reference GC_x) const { return &GC_x; } | |
200 | const_pointer address(const_reference GC_x) const { return &GC_x; } | |
201 | ||
202 | // GC_n is permitted to be 0. The C++ standard says nothing about what | |
203 | // the return value is when GC_n == 0. | |
204 | GC_Tp* allocate(size_type GC_n, const void* = 0) { | |
205 | return static_cast<GC_Tp*>(GC_MALLOC_UNCOLLECTABLE(GC_n * sizeof(GC_Tp))); | |
206 | } | |
207 | ||
208 | // __p is not permitted to be a null pointer. | |
209 | void deallocate(pointer __p, size_type GC_ATTR_UNUSED GC_n) | |
210 | { GC_FREE(__p); } | |
211 | ||
212 | size_type max_size() const throw() | |
213 | { return size_t(-1) / sizeof(GC_Tp); } | |
214 | ||
215 | void construct(pointer __p, const GC_Tp& __val) { new(__p) GC_Tp(__val); } | |
216 | void destroy(pointer __p) { __p->~GC_Tp(); } | |
217 | }; | |
218 | ||
219 | template<> | |
220 | class traceable_allocator<void> { | |
221 | typedef size_t size_type; | |
222 | typedef ptrdiff_t difference_type; | |
223 | typedef void* pointer; | |
224 | typedef const void* const_pointer; | |
225 | typedef void value_type; | |
226 | ||
227 | template <class GC_Tp1> struct rebind { | |
228 | typedef traceable_allocator<GC_Tp1> other; | |
229 | }; | |
230 | }; | |
231 | ||
232 | ||
233 | template <class GC_T1, class GC_T2> | |
234 | inline bool operator==(const traceable_allocator<GC_T1>&, const traceable_allocator<GC_T2>&) | |
235 | { | |
236 | return true; | |
237 | } | |
238 | ||
239 | template <class GC_T1, class GC_T2> | |
240 | inline bool operator!=(const traceable_allocator<GC_T1>&, const traceable_allocator<GC_T2>&) | |
241 | { | |
242 | return false; | |
243 | } | |
244 | ||
245 | #endif /* GC_ALLOCATOR_H */ |