/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You under the Apache License, Version 2.0
 * (the "License"); you may not use this file except in compliance with
 * the License.  You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

#ifndef AXUTIL_ALLOCATOR_H
#define AXUTIL_ALLOCATOR_H

/**
 * @file axutil_allocator.h
 * @brief Axis2 memory allocator interface
 */

#include <axutil_utils_defines.h>

#ifdef __cplusplus
extern "C"
{
#endif

/**
 * @defgroup axutil_allocator allocator
 * @ingroup axis2_util 

 * @{
 */
 
 

/** 
  * \brief Axis2 memory allocator
  *
  * Encapsulator for memory allocating routines
  */
    typedef struct axutil_allocator
    {
      /**
        * allocates memory
        * @param allocator pointer to allocator struct. In the default 
        * implementation this is not used, however this parameter is useful 
        * when the allocator implementation is dealing with a memory pool.
        * @param size size of the memory block to be allocated
        * @return pointer to the allocated memory block
        */
         void * (AXIS2_CALL *malloc_fn) (struct axutil_allocator *allocator, size_t size);
      /**
        * re-llocates memory
        * @param allocator pointer to allocator struct. In the default 
        * implementation this is not used, however this parameter is useful 
        * when the allocator implementation is dealing with a memory pool.
        * @param ptr memory block who's size to be changed
        * @param size size of the memory block to be allocated
        * @return pointer to the allocated memory block
        */
         void * (AXIS2_CALL *realloc) (struct axutil_allocator *allocator, void *ptr, size_t size);
      /**
        * frees memory
        * @param allocator pointer to allocator struct. In the default 
        * implementation this is not used, however this parameter is useful 
        * when the allocator implementation is dealing with a memory pool.
        * @param ptr pointer to be freed
        */
         void (AXIS2_CALL *free_fn) (struct axutil_allocator *allocator, void *ptr);
        /** local memory pool */
         void *local_pool;
        /** global memory pool */
         void *global_pool;
         /** memory pool in use currently */
         void *current_pool;
    } axutil_allocator_t;

  /**
    * Initializes (creates) an allocator.
    * @param allocator user defined allcator. Optional, can be NULL. If NULL, a default allocator will be returned.
    * @return initialized allocator. NULL on error.
    */
    AXIS2_EXTERN axutil_allocator_t * AXIS2_CALL 
    axutil_allocator_init (axutil_allocator_t *allocator);

  /** 
    * This function should be used to deallocate memory if the default allocator provided by
    * axutil_allocator_init() 
    * @param allocator 
    */
    AXIS2_EXTERN void AXIS2_CALL 
    axutil_allocator_free(axutil_allocator_t *allocator);

  /** 
    * Swaps the local_pool and global_pool values. 
    * In case of using pools, local_pool is suppoed to hold the pool out of which
    * local values are allocated. In case of values that live beyond a request 
    * globle pool should be used, hence this method has to be called to swithch to 
    * globle pool for allocation. 
    * @param allocator allocator whose memory pools are to be switched
    */
    AXIS2_EXTERN void AXIS2_CALL 
    axutil_allocator_switch_to_global_pool(axutil_allocator_t *allocator);

  /** 
    * Swaps the local_pool and global_pool values. 
    * In case of using pools, local_pool is suppoed to hold the pool out of which
    * local values are allocated. In case of values that live beyond a request 
    * globle pool should be used. This method can be used to inverse the switching 
    * done by axutil_allocator_switch_to_global_pool, to start using the local pool again.
    * @param allocator allocator whose memory pools are to be switched
    */
    AXIS2_EXTERN void AXIS2_CALL 
    axutil_allocator_switch_to_local_pool(axutil_allocator_t *allocator);

#define AXIS2_MALLOC(allocator, size) \
      ((allocator)->malloc_fn(allocator, size))
   
#define AXIS2_REALLOC(allocator, ptr, size) \
      ((allocator)->realloc(allocator, ptr, size))
      
#define AXIS2_FREE(allocator, ptr) \
      ((allocator)->free_fn(allocator, ptr))

/** @} */
    
#ifdef __cplusplus
}
#endif

#endif    /* AXIS2_ALLOCATOR_H */