1 /*
2 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS HEADER.
3 *
4 * Copyright 2016 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 <stddef.h>
43 #include "allocator.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 16 elements, when
74 * trying to allocate memory on a full pool, it is recommended that you use
75 * a multiple of 16 for the initial size.
76 *
77 * @param n initial pool size (should be a multiple of 16)
78 * @return a pointer to the new memory pool
79 */
80 UcxMempool *ucx_mempool_new(size_t n);
81
82 /**
83 * Resizes a memory pool.
84 *
85 * @param pool the pool to resize
86 * @param newcap the new capacity
87 * @return <code>EXIT_SUCCESS</code> on success or
88 * <code>EXIT_FAILURE</code> on failure
89 */
90 int ucx_mempool_chcap(UcxMempool *pool, size_t newcap);
91
92 /**
93 * Changes the pool size to the next smallest multiple of 16.
94 *
95 * You may use this macro, to reduce the pool size after freeing
96 * many pooled memory items.
97 *
98 * @param pool the pool to clamp
99 * @return <code>EXIT_SUCCESS</code> on success or
100 * <code>EXIT_FAILURE</code> on failure
101 */
102 #define ucx_mempool_clamp(pool) ucx_mempool_chcap(pool, \
103 (pool->ndata & ~0xF)+0x10)
104
105 /**
106 * Allocates pooled memory.
107 *
108 * @param pool the memory pool
109 * @param n amount of memory to allocate
110 * @return a pointer to the allocated memory
111 * @see ucx_allocator_malloc()
112 */
113 void *ucx_mempool_malloc(UcxMempool *pool, size_t n);
114 /**
115 * Allocates a pooled memory array.
116 *
117 * The content of the allocated memory is set to zero.
118 *
119 * @param pool the memory pool
120 * @param nelem amount of elements to allocate
121 * @param elsize amount of memory per element
122 * @return a pointer to the allocated memory
123 * @see ucx_allocator_calloc()
124 */
125 void *ucx_mempool_calloc(UcxMempool *pool, size_t nelem, size_t elsize);
126
127 /**
128 * Reallocates pooled memory.
129 *
130 * If the memory to be reallocated is not contained by the specified pool, the
131 * behavior is undefined.
132 *
133 * @param pool the memory pool
134 * @param ptr a pointer to the memory that shall be reallocated
135 * @param n the new size of the memory
136 * @return a pointer to the new location of the memory
137 * @see ucx_allocator_realloc()
138 */
139 void *ucx_mempool_realloc(UcxMempool *pool, void *ptr, size_t n);
140
141 /**
142 * Frees pooled memory.
143 *
144 * Before freeing the memory, the specified destructor function (if any)
145 * is called.
146 *
147 * If you specify memory, that is not pooled by the specified memory pool, the
148 * behavior is undefined.
149 *
150 * @param pool the memory pool
151 * @param ptr a pointer to the memory that shall be freed
152 * @see ucx_mempool_set_destr()
153 */
154 void ucx_mempool_free(UcxMempool *pool, void *ptr);
155
156 /**
157 * Destroys a memory pool.
158 *
159 * For each element the destructor function (if any) is called and the element
160 * is freed.
161 *
162 * Each of the registered destructor function that has no corresponding element
163 * within the pool (namely those registered by ucx_mempool_reg_destr) is
164 * called interleaving with the element destruction, but with guarantee to the
165 * order in which they were registered (FIFO order).
166 *
167 *
168 * @param pool the mempool to destroy
169 */
170 void ucx_mempool_destroy(UcxMempool *pool);
171
172 /**
173 * Sets a destructor function for the specified memory.
174 *
175 * The destructor is automatically called when the memory is freed or the
176 * pool is destroyed.
177 *
178 * The only requirement for the specified memory is, that it <b>MUST</b> be
179 * pooled memory by a UcxMempool or an element-compatible mempool. The pointer
180 * to the destructor function is saved in a reserved area before the actual
181 * memory.
182 *
183 * @param ptr pooled memory
184 * @param func a pointer to the destructor function
185 * @see ucx_mempool_free()
186 * @see ucx_mempool_destroy()
187 */
188 void ucx_mempool_set_destr(void *ptr, ucx_destructor func);
189
190 /**
191 * Registers a destructor function for the specified (non-pooled) memory.
192 *
193 * This is useful, if you have memory that has not been allocated by a mempool,
194 * but shall be managed by a mempool.
195 *
196 * This function creates an entry in the specified mempool and the memory will
197 * therefore (logically) convert to pooled memory.
198 *
199 * @param pool the memory pool
200 * @param ptr data the destructor is registered for
201 * @param destr a pointer to the destructor function
202 */
203 void ucx_mempool_reg_destr(UcxMempool *pool, void *ptr, ucx_destructor destr);
204
205 #ifdef __cplusplus
206 }
207 #endif
208
209 #endif /* UCX_MEMPOOL_H */
210
211