Mercurial > hg > ucx / file comparison

comparison: src/ucx/mempool.h

src/ucx/mempool.h

changeset 390
d345541018fa
parent 326
3dd7d21fb76b
equal deleted inserted replaced
389:92e482410453 390:d345541018fa
1 /*
2 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS HEADER.
3 *
4 * Copyright 2017 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 /**
30 * @file mempool.h
31 *
32 * Memory pool implementation.
33 *
34 * @author Mike Becker
35 * @author Olaf Wintermann
36 */
37
38 #ifndef UCX_MEMPOOL_H
39 #define UCX_MEMPOOL_H
40
41 #include "ucx.h"
42 #include "allocator.h"
43 #include <stddef.h>
44
45 #ifdef __cplusplus
46 extern "C" {
47 #endif
48
49 /**
50 * UCX mempool structure.
51 */
52 typedef struct {
53 /** UcxAllocator based on this pool */
54 UcxAllocator *allocator;
55
56 /** List of pointers to pooled memory. */
57 void **data;
58
59 /** Count of pooled memory items. */
60 size_t ndata;
61
62 /** Memory pool size. */
63 size_t size;
64 } UcxMempool;
65
66 /** Shorthand for a new default memory pool with a capacity of 16 elements. */
67 #define ucx_mempool_new_default() ucx_mempool_new(16)
68
69
70 /**
71 * Creates a memory pool with the specified initial size.
72 *
73 * As the created memory pool automatically grows in size by factor two when
74 * trying to allocate memory on a full pool, it is recommended that you use
75 * a power of two for the initial size.
76 *
77 * @param n initial pool size (should be a power of two, e.g. 16)
78 * @return a pointer to the new memory pool
79 * @see ucx_mempool_new_default()
80 */
81 UcxMempool *ucx_mempool_new(size_t n);
82
83 /**
84 * Resizes a memory pool.
85 *
86 * This function will fail if the new capacity is not sufficient for the
87 * present data.
88 *
89 * @param pool the pool to resize
90 * @param newcap the new capacity
91 * @return zero on success or non-zero on failure
92 */
93 int ucx_mempool_chcap(UcxMempool *pool, size_t newcap);
94
95 /**
96 * Allocates pooled memory.
97 *
98 * @param pool the memory pool
99 * @param n amount of memory to allocate
100 * @return a pointer to the allocated memory
101 * @see ucx_allocator_malloc()
102 */
103 void *ucx_mempool_malloc(UcxMempool *pool, size_t n);
104 /**
105 * Allocates a pooled memory array.
106 *
107 * The content of the allocated memory is set to zero.
108 *
109 * @param pool the memory pool
110 * @param nelem amount of elements to allocate
111 * @param elsize amount of memory per element
112 * @return a pointer to the allocated memory
113 * @see ucx_allocator_calloc()
114 */
115 void *ucx_mempool_calloc(UcxMempool *pool, size_t nelem, size_t elsize);
116
117 /**
118 * Reallocates pooled memory.
119 *
120 * If the memory to be reallocated is not contained by the specified pool, the
121 * behavior is undefined.
122 *
123 * @param pool the memory pool
124 * @param ptr a pointer to the memory that shall be reallocated
125 * @param n the new size of the memory
126 * @return a pointer to the new location of the memory
127 * @see ucx_allocator_realloc()
128 */
129 void *ucx_mempool_realloc(UcxMempool *pool, void *ptr, size_t n);
130
131 /**
132 * Frees pooled memory.
133 *
134 * Before freeing the memory, the specified destructor function (if any)
135 * is called.
136 *
137 * If you specify memory, that is not pooled by the specified memory pool, the
138 * program will terminate with a call to <code>abort()</code>.
139 *
140 * @param pool the memory pool
141 * @param ptr a pointer to the memory that shall be freed
142 * @see ucx_mempool_set_destr()
143 */
144 void ucx_mempool_free(UcxMempool *pool, void *ptr);
145
146 /**
147 * Destroys a memory pool.
148 *
149 * For each element the destructor function (if any) is called and the element
150 * is freed.
151 *
152 * Each of the registered destructor function that has no corresponding element
153 * within the pool (namely those registered by ucx_mempool_reg_destr) is
154 * called interleaving with the element destruction, but with guarantee to the
155 * order in which they were registered (FIFO order).
156 *
157 *
158 * @param pool the mempool to destroy
159 */
160 void ucx_mempool_destroy(UcxMempool *pool);
161
162 /**
163 * Sets a destructor function for the specified memory.
164 *
165 * The destructor is automatically called when the memory is freed or the
166 * pool is destroyed.
167 * A destructor for pooled memory <b>MUST NOT</b> free the memory itself,
168 * as this is done by the pool. Use a destructor to free any resources
169 * managed by the pooled object.
170 *
171 * The only requirement for the specified memory is, that it <b>MUST</b> be
172 * pooled memory by a UcxMempool or an element-compatible mempool. The pointer
173 * to the destructor function is saved in a reserved area before the actual
174 * memory.
175 *
176 * @param ptr pooled memory
177 * @param func a pointer to the destructor function
178 * @see ucx_mempool_free()
179 * @see ucx_mempool_destroy()
180 */
181 void ucx_mempool_set_destr(void *ptr, ucx_destructor func);
182
183 /**
184 * Registers a destructor function for the specified (non-pooled) memory.
185 *
186 * This is useful, if you have memory that has not been allocated by a mempool,
187 * but shall be managed by a mempool.
188 *
189 * This function creates an entry in the specified mempool and the memory will
190 * therefore (logically) convert to pooled memory.
191 * <b>However, this does not cause the memory to be freed automatically!</b>.
192 * If you want to use this function, make the memory pool free non-pooled
193 * memory, the specified destructor function must call <code>free()</code>
194 * by itself. But keep in mind, that you then MUST NOT use this destructor
195 * function with pooled memory (e.g. in ucx_mempool_set_destr()), as it
196 * would cause a double-free.
197 *
198 * @param pool the memory pool
199 * @param ptr data the destructor is registered for
200 * @param destr a pointer to the destructor function
201 */
202 void ucx_mempool_reg_destr(UcxMempool *pool, void *ptr, ucx_destructor destr);
203
204 #ifdef __cplusplus
205 }
206 #endif
207
208 #endif /* UCX_MEMPOOL_H */
209

Mercurial Repository: ucx

mercurial