Mercurial > hg > ucx / file revision

 /*

  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS HEADER.

  *

  * Copyright 2015 Olaf Wintermann. All rights reserved.

  *

  * Redistribution and use in source and binary forms, with or without

  * modification, are permitted provided that the following conditions are met:

  *

  *   1. Redistributions of source code must retain the above copyright

  *      notice, this list of conditions and the following disclaimer.

  *

  *   2. Redistributions in binary form must reproduce the above copyright

  *      notice, this list of conditions and the following disclaimer in the

  *      documentation and/or other materials provided with the distribution.

  *

  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"

  * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE

  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE

  * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE

  * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR

  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF

  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS

  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN

  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)

  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE

  * POSSIBILITY OF SUCH DAMAGE.

  */

 /**

  * @file mempool.h

  * 

  * Memory pool implementation.

  * 

  * @author Mike Becker

  * @author Olaf Wintermann

  */

 #ifndef UCX_MEMPOOL_H

 #define	UCX_MEMPOOL_H

 #include "ucx.h"

 #include <stddef.h>

 #include "allocator.h"

 #ifdef	__cplusplus

 extern "C" {

 #endif

 /**

  * A function pointer to a destructor function.

  * @see ucx_mempool_setdestr()

  * @see ucx_mempool_regdestr()

  */

 typedef void(*ucx_destructor)(void*);

 /**

  * UCX mempool structure.

  */

 typedef struct {

     /** UcxAllocator based on this pool */

     UcxAllocator *allocator;

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

     void         **data;

     /** Count of pooled memory items. */

     size_t       ndata;

     /** Memory pool size. */

     size_t       size;

 } UcxMempool;

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

 #define ucx_mempool_new_default() ucx_mempool_new(16)

 /**

  * Creates a memory pool with the specified initial size.

  * 

  * As the created memory pool automatically grows in size by 16 elements, when

  * trying to allocate memory on a full pool, it is recommended that you use

  * a multiple of 16 for the initial size.

  * 

  * @param n initial pool size (should be a multiple of 16)

  * @return a pointer to the new memory pool

  */

 UcxMempool *ucx_mempool_new(size_t n);

 /**

  * Resizes a memory pool.

  * 

  * @param pool the pool to resize

  * @param newcap the new capacity

  * @return <code>EXIT_SUCCESS</code> on success or

  * <code>EXIT_FAILURE</code> on failure

  */

 int ucx_mempool_chcap(UcxMempool *pool, size_t newcap);

 /**

  * Changes the pool size to the next smallest multiple of 16.

  * 

  * You may use this macro, to reduce the pool size after freeing

  * many pooled memory items.

  * 

  * @param pool the pool to clamp

  * @return <code>EXIT_SUCCESS</code> on success or

  * <code>EXIT_FAILURE</code> on failure

  */

 #define ucx_mempool_clamp(pool) ucx_mempool_chcap(pool, \

         (pool->ndata & ~0xF)+0x10)

 /**

  * Allocates pooled memory.

  * 

  * @param pool the memory pool

  * @param n amount of memory to allocate

  * @return a pointer to the allocated memory

  * @see ucx_allocator_malloc()

  */

 void *ucx_mempool_malloc(UcxMempool *pool, size_t n);

 /**

  * Allocates a pooled memory array.

  * 

  * The content of the allocated memory is set to zero.

  * 

  * @param pool the memory pool

  * @param nelem amount of elements to allocate

  * @param elsize amount of memory per element

  * @return a pointer to the allocated memory

  * @see ucx_allocator_calloc()

  */

 void *ucx_mempool_calloc(UcxMempool *pool, size_t nelem, size_t elsize);

 /**

  * Reallocates pooled memory.

  * 

  * If the memory to be reallocated is not contained by the specified pool, this

  * function will possibly fail. In case the memory had to be moved to another

  * location, this function will print out a message to <code>stderr</code>

  * and exit the program with error code <code>EXIT_FAILURE</code>.

  * 

  * @param pool the memory pool

  * @param ptr a pointer to the memory that shall be reallocated

  * @param n the new size of the memory

  * @return a pointer to the new location of the memory

  * @see ucx_allocator_realloc()

  */

 void *ucx_mempool_realloc(UcxMempool *pool, void *ptr, size_t n);

 /**

  * Frees pooled memory.

  * 

  * Before freeing the memory, the specified destructor function (if any)

  * is called.

  * 

  * If you specify memory, that is not pooled by the specified memory pool, this

  * is considered as a severe error and an error message is written to

  * <code>stderr</code> and the application is shut down with code

  * <code>EXIT_FAILURE</code>.

  * 

  * @param pool the memory pool

  * @param ptr a pointer to the memory that shall be freed

  * @see ucx_mempool_set_destr()

  */

 void ucx_mempool_free(UcxMempool *pool, void *ptr);

 /**

  * Destroys a memory pool.

  * 

  * For each element the destructor function (if any) is called and the element

  * is freed.

  * 

  * Each of the registered destructor function that has no corresponding element

  * within the pool (namely those registered by ucx_mempool_reg_destr) is

  * called interleaving with the element destruction, but with guarantee to the

  * order in which they were registered (FIFO order).

  * 

  * 

  * @param pool the mempool to destroy

  */

 void ucx_mempool_destroy(UcxMempool *pool);

 /**

  * Sets a destructor function for the specified memory.

  * 

  * The destructor is automatically called when the memory is freed or the

  * pool is destroyed.

  * 

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

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

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

  * memory.

  * 

  * @param ptr pooled memory

  * @param func a pointer to the destructor function

  * @see ucx_mempool_free()

  * @see ucx_mempool_destroy()

  */

 void ucx_mempool_set_destr(void *ptr, ucx_destructor func);

 /**

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

  * 

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

  * but shall be managed by a mempool.

  * 

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

  * therefore (logically) convert to pooled memory.

  * 

  * @param pool the memory pool

  * @param ptr data the destructor is registered for

  * @param destr a pointer to the destructor function

  */

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

 #ifdef	__cplusplus

 }

 #endif

 #endif	/* UCX_MEMPOOL_H */