1 /*
2 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS HEADER.
3 *
4 * Copyright 2021 Mike Becker, Olaf Wintermann All rights reserved.
5 *
6 * Redistribution and use in source and binary forms, with or without
7 * modification, are permitted provided that the following conditions are met:
8 *
9 * 1. Redistributions of source code must retain the above copyright
10 * notice, this list of conditions and the following disclaimer.
11 *
12 * 2. Redistributions in binary form must reproduce the above copyright
13 * notice, this list of conditions and the following disclaimer in the
14 * documentation and/or other materials provided with the distribution.
15 *
16 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
17 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
18 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
19 * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
20 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
21 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
22 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
23 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
24 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
25 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
26 * POSSIBILITY OF SUCH DAMAGE.
27 */
28 /**
29 * \file allocator.h
30 * Interface for custom allocators.
31 */
32
33 #ifndef UCX_ALLOCATOR_H
34 #define UCX_ALLOCATOR_H
35
36 #include "common.h"
37
38 #ifdef __cplusplus
39 extern "C" {
40 #endif
41
42 /**
43 * The class definition for an allocator.
44 */
45 typedef struct {
46 /**
47 * The allocator's malloc() implementation.
48 */
49 void *(*malloc)(
50 void *data,
51 size_t n
52 );
53
54 /**
55 * The allocator's realloc() implementation.
56 */
57 void *(*realloc)(
58 void *data,
59 void *mem,
60 size_t n
61 )
62 __attribute__((__warn_unused_result__));
63
64 /**
65 * The allocator's calloc() implementation.
66 */
67 void *(*calloc)(
68 void *data,
69 size_t nelem,
70 size_t n
71 );
72
73 /**
74 * The allocator's free() implementation.
75 */
76 void (*free)(
77 void *data,
78 void *mem
79 )
80 __attribute__((__nonnull__));
81 } cx_allocator_class;
82
83 /**
84 * Structure holding the data for an allocator.
85 */
86 struct cx_allocator_s {
87 /**
88 * A pointer to the instance of the allocator class.
89 */
90 cx_allocator_class *cl;
91 /**
92 * A pointer to the data this allocator uses.
93 */
94 void *data;
95 };
96
97 /**
98 * High-Level type alias for the allocator type.
99 */
100 typedef struct cx_allocator_s CxAllocator;
101
102 /**
103 * A default allocator using standard library malloc() etc.
104 */
105 extern CxAllocator *cxDefaultAllocator;
106
107 /**
108 * Function pointer type for destructor functions.
109 *
110 * A destructor function deallocates possible contents and MAY free the memory
111 * pointed to by \p memory. Read the documentation of the respective function
112 * pointer to learn if a destructor SHALL, MAY, or MUST NOT free the memory in that
113 * particular implementation.
114 *
115 * @param memory a pointer to the object to destruct
116 */
117 typedef void (*cx_destructor_func)(void *memory) __attribute__((__nonnull__));
118
119 /**
120 * Function pointer type for destructor functions.
121 *
122 * A destructor function deallocates possible contents and MAY free the memory
123 * pointed to by \p memory. Read the documentation of the respective function
124 * pointer to learn if a destructor SHALL, MAY, or MUST NOT free the memory in that
125 * particular implementation.
126 *
127 * @param data an optional pointer to custom data
128 * @param memory a pointer to the object to destruct
129 */
130 typedef void (*cx_destructor_func2)(
131 void *data,
132 void *memory
133 ) __attribute__((__nonnull__(2)));
134
135 /**
136 * Re-allocate a previously allocated block and changes the pointer in-place, if necessary.
137 *
138 * \par Error handling
139 * \c errno will be set by realloc() on failure.
140 *
141 * @param mem pointer to the pointer to allocated block
142 * @param n the new size in bytes
143 * @return zero on success, non-zero on failure
144 */
145 int cx_reallocate(
146 void **mem,
147 size_t n
148 )
149 __attribute__((__nonnull__));
150
151 /**
152 * Allocate \p n bytes of memory.
153 *
154 * @param allocator the allocator
155 * @param n the number of bytes
156 * @return a pointer to the allocated memory
157 */
158 void *cxMalloc(
159 CxAllocator const *allocator,
160 size_t n
161 )
162 __attribute__((__malloc__))
163 __attribute__((__alloc_size__(2)));
164
165 /**
166 * Re-allocate the previously allocated block in \p mem, making the new block \p n bytes long.
167 * This function may return the same pointer that was passed to it, if moving the memory
168 * was not necessary.
169 *
170 * \note Re-allocating a block allocated by a different allocator is undefined.
171 *
172 * @param allocator the allocator
173 * @param mem pointer to the previously allocated block
174 * @param n the new size in bytes
175 * @return a pointer to the re-allocated memory
176 */
177 void *cxRealloc(
178 CxAllocator const *allocator,
179 void *mem,
180 size_t n
181 )
182 __attribute__((__warn_unused_result__))
183 __attribute__((__alloc_size__(3)));
184
185 /**
186 * Re-allocate a previously allocated block and changes the pointer in-place, if necessary.
187 * This function acts like cxRealloc() using the pointer pointed to by \p mem.
188 *
189 * \note Re-allocating a block allocated by a different allocator is undefined.
190 *
191 * \par Error handling
192 * \c errno will be set, if the underlying realloc function does so.
193 *
194 * @param allocator the allocator
195 * @param mem pointer to the pointer to allocated block
196 * @param n the new size in bytes
197 * @return zero on success, non-zero on failure
198 */
199 int cxReallocate(
200 CxAllocator const *allocator,
201 void **mem,
202 size_t n
203 )
204 __attribute__((__nonnull__));
205
206 /**
207 * Allocate \p nelem elements of \p n bytes each, all initialized to zero.
208 *
209 * @param allocator the allocator
210 * @param nelem the number of elements
211 * @param n the size of each element in bytes
212 * @return a pointer to the allocated memory
213 */
214 void *cxCalloc(
215 CxAllocator const *allocator,
216 size_t nelem,
217 size_t n
218 )
219 __attribute__((__malloc__))
220 __attribute__((__alloc_size__(2, 3)));
221
222 /**
223 * Free a block allocated by this allocator.
224 *
225 * \note Freeing a block of a different allocator is undefined.
226 *
227 * @param allocator the allocator
228 * @param mem a pointer to the block to free
229 */
230 void cxFree(
231 CxAllocator const *allocator,
232 void *mem
233 )
234 __attribute__((__nonnull__));
235
236 #ifdef __cplusplus
237 } // extern "C"
238 #endif
239
240 #endif // UCX_ALLOCATOR_H
241