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6991c6c9 JS |
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 | ||
aa7a966b BM |
38 | #ifndef GC_ALLOCATOR_H |
39 | ||
40 | #define GC_ALLOCATOR_H | |
41 | ||
42 | #include "gc.h" | |
43 | ||
44 | #if defined(__GNUC__) | |
45 | # define GC_ATTR_UNUSED __attribute__((unused)) | |
46 | #else | |
47 | # define GC_ATTR_UNUSED | |
48 | #endif | |
6991c6c9 JS |
49 | |
50 | /* First some helpers to allow us to dispatch on whether or not a type | |
51 | * is known to be pointerfree. | |
52 | * These are private, except that the client may invoke the | |
53 | * GC_DECLARE_PTRFREE macro. | |
54 | */ | |
55 | ||
56 | struct GC_true_type {}; | |
57 | struct GC_false_type {}; | |
58 | ||
59 | template <class GC_tp> | |
60 | struct GC_type_traits { | |
61 | GC_false_type GC_is_ptr_free; | |
62 | }; | |
63 | ||
64 | # define GC_DECLARE_PTRFREE(T) \ | |
65 | template<> struct GC_type_traits<T> { GC_true_type GC_is_ptr_free; } | |
66 | ||
67 | GC_DECLARE_PTRFREE(signed char); | |
68 | GC_DECLARE_PTRFREE(unsigned char); | |
69 | GC_DECLARE_PTRFREE(signed short); | |
70 | GC_DECLARE_PTRFREE(unsigned short); | |
71 | GC_DECLARE_PTRFREE(signed int); | |
72 | GC_DECLARE_PTRFREE(unsigned int); | |
73 | GC_DECLARE_PTRFREE(signed long); | |
74 | GC_DECLARE_PTRFREE(unsigned long); | |
75 | GC_DECLARE_PTRFREE(float); | |
76 | GC_DECLARE_PTRFREE(double); | |
77 | /* The client may want to add others. */ | |
78 | ||
79 | // In the following GC_Tp is GC_true_type iff we are allocating a | |
80 | // pointerfree object. | |
81 | template <class GC_Tp> | |
82 | inline void * GC_selective_alloc(size_t n, GC_Tp) { | |
83 | return GC_MALLOC(n); | |
84 | } | |
85 | ||
86 | template <> | |
87 | inline void * GC_selective_alloc<GC_true_type>(size_t n, GC_true_type) { | |
88 | return GC_MALLOC_ATOMIC(n); | |
89 | } | |
90 | ||
91 | /* Now the public gc_allocator<T> class: | |
92 | */ | |
93 | template <class GC_Tp> | |
94 | class gc_allocator { | |
95 | public: | |
96 | typedef size_t size_type; | |
97 | typedef ptrdiff_t difference_type; | |
98 | typedef GC_Tp* pointer; | |
99 | typedef const GC_Tp* const_pointer; | |
100 | typedef GC_Tp& reference; | |
101 | typedef const GC_Tp& const_reference; | |
102 | typedef GC_Tp value_type; | |
103 | ||
104 | template <class GC_Tp1> struct rebind { | |
105 | typedef gc_allocator<GC_Tp1> other; | |
106 | }; | |
107 | ||
108 | gc_allocator() {} | |
109 | # ifndef _MSC_VER | |
110 | // I'm not sure why this is needed here in addition to the following. | |
111 | // The standard specifies it for the standard allocator, but VC++ rejects | |
112 | // it. -HB | |
113 | gc_allocator(const gc_allocator&) throw() {} | |
114 | # endif | |
115 | template <class GC_Tp1> gc_allocator(const gc_allocator<GC_Tp1>&) throw() {} | |
116 | ~gc_allocator() throw() {} | |
117 | ||
118 | pointer address(reference GC_x) const { return &GC_x; } | |
119 | const_pointer address(const_reference GC_x) const { return &GC_x; } | |
120 | ||
121 | // GC_n is permitted to be 0. The C++ standard says nothing about what | |
122 | // the return value is when GC_n == 0. | |
123 | GC_Tp* allocate(size_type GC_n, const void* = 0) { | |
124 | GC_type_traits<GC_Tp> traits; | |
125 | return static_cast<GC_Tp *> | |
126 | (GC_selective_alloc(GC_n * sizeof(GC_Tp), | |
127 | traits.GC_is_ptr_free)); | |
128 | } | |
129 | ||
130 | // __p is not permitted to be a null pointer. | |
aa7a966b | 131 | void deallocate(pointer __p, size_type GC_ATTR_UNUSED GC_n) |
6991c6c9 JS |
132 | { GC_FREE(__p); } |
133 | ||
134 | size_type max_size() const throw() | |
135 | { return size_t(-1) / sizeof(GC_Tp); } | |
136 | ||
137 | void construct(pointer __p, const GC_Tp& __val) { new(__p) GC_Tp(__val); } | |
138 | void destroy(pointer __p) { __p->~GC_Tp(); } | |
139 | }; | |
140 | ||
141 | template<> | |
142 | class gc_allocator<void> { | |
143 | typedef size_t size_type; | |
144 | typedef ptrdiff_t difference_type; | |
145 | typedef void* pointer; | |
146 | typedef const void* const_pointer; | |
147 | typedef void value_type; | |
148 | ||
149 | template <class GC_Tp1> struct rebind { | |
150 | typedef gc_allocator<GC_Tp1> other; | |
151 | }; | |
152 | }; | |
153 | ||
154 | ||
155 | template <class GC_T1, class GC_T2> | |
156 | inline bool operator==(const gc_allocator<GC_T1>&, const gc_allocator<GC_T2>&) | |
157 | { | |
158 | return true; | |
159 | } | |
160 | ||
161 | template <class GC_T1, class GC_T2> | |
162 | inline bool operator!=(const gc_allocator<GC_T1>&, const gc_allocator<GC_T2>&) | |
163 | { | |
164 | return false; | |
165 | } | |
166 | ||
167 | /* | |
168 | * And the public traceable_allocator class. | |
169 | */ | |
170 | ||
171 | // Note that we currently don't specialize the pointer-free case, since a | |
172 | // pointer-free traceable container doesn't make that much sense, | |
173 | // though it could become an issue due to abstraction boundaries. | |
174 | template <class GC_Tp> | |
175 | class traceable_allocator { | |
176 | public: | |
177 | typedef size_t size_type; | |
178 | typedef ptrdiff_t difference_type; | |
179 | typedef GC_Tp* pointer; | |
180 | typedef const GC_Tp* const_pointer; | |
181 | typedef GC_Tp& reference; | |
182 | typedef const GC_Tp& const_reference; | |
183 | typedef GC_Tp value_type; | |
184 | ||
185 | template <class GC_Tp1> struct rebind { | |
186 | typedef traceable_allocator<GC_Tp1> other; | |
187 | }; | |
188 | ||
189 | traceable_allocator() throw() {} | |
190 | # ifndef _MSC_VER | |
191 | traceable_allocator(const traceable_allocator&) throw() {} | |
192 | # endif | |
193 | template <class GC_Tp1> traceable_allocator | |
194 | (const traceable_allocator<GC_Tp1>&) throw() {} | |
195 | ~traceable_allocator() throw() {} | |
196 | ||
197 | pointer address(reference GC_x) const { return &GC_x; } | |
198 | const_pointer address(const_reference GC_x) const { return &GC_x; } | |
199 | ||
200 | // GC_n is permitted to be 0. The C++ standard says nothing about what | |
201 | // the return value is when GC_n == 0. | |
202 | GC_Tp* allocate(size_type GC_n, const void* = 0) { | |
203 | return static_cast<GC_Tp*>(GC_MALLOC_UNCOLLECTABLE(GC_n * sizeof(GC_Tp))); | |
204 | } | |
205 | ||
206 | // __p is not permitted to be a null pointer. | |
aa7a966b | 207 | void deallocate(pointer __p, size_type GC_ATTR_UNUSED GC_n) |
6991c6c9 JS |
208 | { GC_FREE(__p); } |
209 | ||
210 | size_type max_size() const throw() | |
211 | { return size_t(-1) / sizeof(GC_Tp); } | |
212 | ||
213 | void construct(pointer __p, const GC_Tp& __val) { new(__p) GC_Tp(__val); } | |
214 | void destroy(pointer __p) { __p->~GC_Tp(); } | |
215 | }; | |
216 | ||
217 | template<> | |
218 | class traceable_allocator<void> { | |
219 | typedef size_t size_type; | |
220 | typedef ptrdiff_t difference_type; | |
221 | typedef void* pointer; | |
222 | typedef const void* const_pointer; | |
223 | typedef void value_type; | |
224 | ||
225 | template <class GC_Tp1> struct rebind { | |
226 | typedef traceable_allocator<GC_Tp1> other; | |
227 | }; | |
228 | }; | |
229 | ||
230 | ||
231 | template <class GC_T1, class GC_T2> | |
232 | inline bool operator==(const traceable_allocator<GC_T1>&, const traceable_allocator<GC_T2>&) | |
233 | { | |
234 | return true; | |
235 | } | |
236 | ||
237 | template <class GC_T1, class GC_T2> | |
238 | inline bool operator!=(const traceable_allocator<GC_T1>&, const traceable_allocator<GC_T2>&) | |
239 | { | |
240 | return false; | |
241 | } | |
242 | ||
aa7a966b | 243 | #endif /* GC_ALLOCATOR_H */ |