ucx: ucx/mempool.h@a1a068c2c4ef

     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  */

    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  * UCX mempool structure.

    51  */

    52 typedef struct {

    53     /** UcxAllocator based on this pool */

    54     UcxAllocator *allocator;

    56     /** List of pointers to pooled memory. */

    57     void         **data;

    59     /** Count of pooled memory items. */

    60     size_t       ndata;

    62     /** Memory pool size. */

    63     size_t       size;

    64 } UcxMempool;

    66 /** Shorthand for a new default memory pool with a capacity of 16 elements. */

    67 #define ucx_mempool_new_default() ucx_mempool_new(16)

    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);

    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);

    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)

   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);

   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);

   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);

   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);

   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);

   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);

   205 #ifdef	__cplusplus

   206 }

   207 #endif

   209 #endif	/* UCX_MEMPOOL_H */

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