ucx: src/ucx/mempool.h@2f5dea574a75

     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  */

    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 "allocator.h"

    43 #include <stddef.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 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);

    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);

    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);

   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);

   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);

   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);

   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  *

   168  * The only requirement for the specified memory is, that it <b>MUST</b> be

   169  * pooled memory by a UcxMempool or an element-compatible mempool. The pointer

   170  * to the destructor function is saved in a reserved area before the actual

   171  * memory.

   172  *

   173  * @param ptr pooled memory

   174  * @param func a pointer to the destructor function

   175  * @see ucx_mempool_free()

   176  * @see ucx_mempool_destroy()

   177  */

   178 void ucx_mempool_set_destr(void *ptr, ucx_destructor func);

   180 /**

   181  * Registers a destructor function for the specified (non-pooled) memory.

   182  *

   183  * This is useful, if you have memory that has not been allocated by a mempool,

   184  * but shall be managed by a mempool.

   185  *

   186  * This function creates an entry in the specified mempool and the memory will

   187  * therefore (logically) convert to pooled memory.

   188  *

   189  * @param pool the memory pool

   190  * @param ptr data the destructor is registered for

   191  * @param destr a pointer to the destructor function

   192  */

   193 void ucx_mempool_reg_destr(UcxMempool *pool, void *ptr, ucx_destructor destr);

   195 #ifdef	__cplusplus

   196 }

   197 #endif

   199 #endif	/* UCX_MEMPOOL_H */

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