Wed, 14 Aug 2013 13:13:36 +0200
added mempool clamp + some minor fixes
1 /*
2 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS HEADER.
3 *
4 * Copyright 2013 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 */
29 /**
30 * @file mempool.h
31 *
32 * Memory pool implementation.
33 *
34 * @author Mike Becker
35 * @author Olaf Wintermann
36 */
38 #ifndef UCX_MEMPOOL_H
39 #define UCX_MEMPOOL_H
41 #include "ucx.h"
42 #include <stddef.h>
43 #include "allocator.h"
45 #ifdef __cplusplus
46 extern "C" {
47 #endif
49 /**
50 * A function pointer to a destructor function.
51 * @see ucx_mempool_setdestr()
52 * @see ucx_mempool_regdestr()
53 */
54 typedef void(*ucx_destructor)(void*);
56 /**
57 * UCX mempool structure.
58 */
59 typedef struct {
60 /** List of pointers to pooled memory. */
61 void **data;
62 /** Count of pooled memory items. */
63 size_t ndata;
64 /** Memory pool size. */
65 size_t size;
66 } UcxMempool;
68 /** Shorthand for a new default memory pool with a capacity of 16 elements. */
69 #define ucx_mempool_new_default() ucx_mempool_new(16)
72 /**
73 * Creates a memory pool with the specified initial size.
74 *
75 * As the created memory pool automatically grows in size by 16 elements, when
76 * trying to allocate memory on a full pool, it is recommended that you use
77 * a multiple of 16 for the initial size.
78 *
79 * @param n initial pool size (should be a multiple of 16)
80 * @return a pointer to the new memory pool
81 */
82 UcxMempool *ucx_mempool_new(size_t n);
84 /**
85 * Resizes a memory pool.
86 *
87 * @param pool the pool to resize
88 * @param newcap the new capacity
89 * @return <code>EXIT_SUCCESS</code> on success or
90 * <code>EXIT_FAILURE</code> on failure
91 */
92 int ucx_mempool_chcap(UcxMempool *pool, size_t newcap);
94 /**
95 * Changes the pool size to the next smallest multiple of 16.
96 *
97 * You may use this macro, to reduce the pool size after freeing
98 * many pooled memory items.
99 *
100 * @param pool the pool to clamp
101 * @return <code>EXIT_SUCCESS</code> on success or
102 * <code>EXIT_FAILURE</code> on failure
103 */
104 #define ucx_mempool_clamp(pool) ucx_mempool_chcap(pool, \
105 (pool->ndata & ~0xF)+0x10)
107 /**
108 * Allocates pooled memory.
109 *
110 * @param pool the memory pool
111 * @param n amount of memory to allocate
112 * @return a pointer to the allocated memory
113 * @see ucx_allocator_malloc()
114 */
115 void *ucx_mempool_malloc(UcxMempool *pool, size_t n);
116 /**
117 * Allocates a pooled memory array.
118 *
119 * The contents of the allocated memory is set to zero.
120 *
121 * @param pool the memory pool
122 * @param nelem amount of elements to allocate
123 * @param elsize amount of memory per element
124 * @return a pointer to the allocated memory
125 * @see ucx_allocator_calloc()
126 */
127 void *ucx_mempool_calloc(UcxMempool *pool, size_t nelem, size_t elsize);
128 /**
129 * Reallocates pooled memory.
130 *
131 * If the memory to be reallocated is not contained by the specified pool, this
132 * function will possibly fail. In case the memory had to be moved to another
133 * location, this function will print out a message to <code>stderr</code>
134 * and exit the program with error code <code>EXIT_FAILURE</code>.
135 *
136 * @param pool the memory pool
137 * @param ptr a pointer to the memory that shall be reallocated
138 * @param n the new size of the memory
139 * @return a pointer to the the location of the memory
140 * @see ucx_allocator_realloc()
141 */
142 void *ucx_mempool_realloc(UcxMempool *pool, void *ptr, size_t n);
143 /**
144 * Frees pooled memory.
145 *
146 * Before freeing the memory, the specified destructor function (if any)
147 * is called.
148 *
149 * If you specify memory, that is not pooled by the specified memory pool, this
150 * is considered as a severe error and an error message is written to
151 * <code>stderr</code> and the application is shut down with code
152 * <code>EXIT_FAILURE</code>.
153 *
154 * @param pool the memory pool
155 * @param ptr a pointer to the memory that shall be freed
156 * @see ucx_mempool_set_destr()
157 */
158 void ucx_mempool_free(UcxMempool *pool, void *ptr);
160 /**
161 * Destroys a memory pool.
162 *
163 * For each element the destructor function (if any) is called and the element
164 * is freed.
165 *
166 * Each of the registered destructor function that has no corresponding element
167 * within the pool (namely those registered by ucx_mempool_reg_destr) is
168 * called interleaving with the element destruction, but with guarantee to the
169 * order in which they were registered (FIFO order).
170 *
171 *
172 * @param pool the mempool to destroy
173 */
174 void ucx_mempool_destroy(UcxMempool *pool);
176 /**
177 * Sets a destructor function for the specified memory.
178 *
179 * The destructor is automatically called when the memory is freed or the
180 * pool is destroyed.
181 *
182 * The only requirement for the specified memory is, that it <b>MUST</b> be
183 * pooled memory by an UcxMempool or an element-compatible mempool. The pointer
184 * to the destructor function is saved in a reserved area before the actual
185 * memory.
186 *
187 * @param ptr pooled memory
188 * @param func a pointer to the destructor function
189 * @see ucx_mempool_free()
190 * @see ucx_mempool_destroy()
191 */
192 void ucx_mempool_set_destr(void *ptr, ucx_destructor func);
194 /**
195 * Registers a destructor function for the specified (non-pooled) memory.
196 *
197 * This is useful, if you have memory that has not been allocated by a mempool,
198 * but shall be managed by a mempool.
199 *
200 * This function creates an entry in the specified mempool and the memory will
201 * therefore (logically) convert to pooled memory.
202 *
203 * @param pool the memory pool
204 * @param ptr data the destructor is registered for
205 * @param destr a pointer to the destructor function
206 */
207 void ucx_mempool_reg_destr(UcxMempool *pool, void *ptr, ucx_destructor destr);
209 /**
210 * Creates an UcxAllocator based on an UcxMempool.
211 *
212 * @param pool the mempool to create the UcxAllocator for
213 * @return a new UcxAllocator based on the specified pool
214 */
215 UcxAllocator* ucx_mempool_allocator(UcxMempool *pool);
217 #ifdef __cplusplus
218 }
219 #endif
221 #endif /* UCX_MEMPOOL_H */