apr_allocator.h revision 253734
1/* Licensed to the Apache Software Foundation (ASF) under one or more 2 * contributor license agreements. See the NOTICE file distributed with 3 * this work for additional information regarding copyright ownership. 4 * The ASF licenses this file to You under the Apache License, Version 2.0 5 * (the "License"); you may not use this file except in compliance with 6 * the License. You may obtain a copy of the License at 7 * 8 * http://www.apache.org/licenses/LICENSE-2.0 9 * 10 * Unless required by applicable law or agreed to in writing, software 11 * distributed under the License is distributed on an "AS IS" BASIS, 12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 13 * See the License for the specific language governing permissions and 14 * limitations under the License. 15 */ 16 17#ifndef APR_ALLOCATOR_H 18#define APR_ALLOCATOR_H 19 20/** 21 * @file apr_allocator.h 22 * @brief APR Internal Memory Allocation 23 */ 24 25#include "apr.h" 26#include "apr_errno.h" 27#define APR_WANT_MEMFUNC /**< For no good reason? */ 28#include "apr_want.h" 29 30#ifdef __cplusplus 31extern "C" { 32#endif 33 34/** 35 * @defgroup apr_allocator Internal Memory Allocation 36 * @ingroup APR 37 * @{ 38 */ 39 40/** the allocator structure */ 41typedef struct apr_allocator_t apr_allocator_t; 42/** the structure which holds information about the allocation */ 43typedef struct apr_memnode_t apr_memnode_t; 44 45/** basic memory node structure 46 * @note The next, ref and first_avail fields are available for use by the 47 * caller of apr_allocator_alloc(), the remaining fields are read-only. 48 * The next field has to be used with caution and sensibly set when the 49 * memnode is passed back to apr_allocator_free(). See apr_allocator_free() 50 * for details. 51 * The ref and first_avail fields will be properly restored by 52 * apr_allocator_free(). 53 */ 54struct apr_memnode_t { 55 apr_memnode_t *next; /**< next memnode */ 56 apr_memnode_t **ref; /**< reference to self */ 57 apr_uint32_t index; /**< size */ 58 apr_uint32_t free_index; /**< how much free */ 59 char *first_avail; /**< pointer to first free memory */ 60 char *endp; /**< pointer to end of free memory */ 61}; 62 63/** The base size of a memory node - aligned. */ 64#define APR_MEMNODE_T_SIZE APR_ALIGN_DEFAULT(sizeof(apr_memnode_t)) 65 66/** Symbolic constants */ 67#define APR_ALLOCATOR_MAX_FREE_UNLIMITED 0 68 69/** 70 * Create a new allocator 71 * @param allocator The allocator we have just created. 72 * 73 */ 74APR_DECLARE(apr_status_t) apr_allocator_create(apr_allocator_t **allocator) 75 __attribute__((nonnull(1))); 76 77/** 78 * Destroy an allocator 79 * @param allocator The allocator to be destroyed 80 * @remark Any memnodes not given back to the allocator prior to destroying 81 * will _not_ be free()d. 82 */ 83APR_DECLARE(void) apr_allocator_destroy(apr_allocator_t *allocator) 84 __attribute__((nonnull(1))); 85 86/** 87 * Allocate a block of mem from the allocator 88 * @param allocator The allocator to allocate from 89 * @param size The size of the mem to allocate (excluding the 90 * memnode structure) 91 */ 92APR_DECLARE(apr_memnode_t *) apr_allocator_alloc(apr_allocator_t *allocator, 93 apr_size_t size) 94 __attribute__((nonnull(1))); 95 96/** 97 * Free a list of blocks of mem, giving them back to the allocator. 98 * The list is typically terminated by a memnode with its next field 99 * set to NULL. 100 * @param allocator The allocator to give the mem back to 101 * @param memnode The memory node to return 102 */ 103APR_DECLARE(void) apr_allocator_free(apr_allocator_t *allocator, 104 apr_memnode_t *memnode) 105 __attribute__((nonnull(1,2))); 106 107#include "apr_pools.h" 108 109/** 110 * Set the owner of the allocator 111 * @param allocator The allocator to set the owner for 112 * @param pool The pool that is to own the allocator 113 * @remark Typically pool is the highest level pool using the allocator 114 */ 115/* 116 * XXX: see if we can come up with something a bit better. Currently 117 * you can make a pool an owner, but if the pool doesn't use the allocator 118 * the allocator will never be destroyed. 119 */ 120APR_DECLARE(void) apr_allocator_owner_set(apr_allocator_t *allocator, 121 apr_pool_t *pool) 122 __attribute__((nonnull(1))); 123 124/** 125 * Get the current owner of the allocator 126 * @param allocator The allocator to get the owner from 127 */ 128APR_DECLARE(apr_pool_t *) apr_allocator_owner_get(apr_allocator_t *allocator) 129 __attribute__((nonnull(1))); 130 131/** 132 * Set the current threshold at which the allocator should start 133 * giving blocks back to the system. 134 * @param allocator The allocator the set the threshold on 135 * @param size The threshold. 0 == unlimited. 136 */ 137APR_DECLARE(void) apr_allocator_max_free_set(apr_allocator_t *allocator, 138 apr_size_t size) 139 __attribute__((nonnull(1))); 140 141#include "apr_thread_mutex.h" 142 143#if APR_HAS_THREADS 144/** 145 * Set a mutex for the allocator to use 146 * @param allocator The allocator to set the mutex for 147 * @param mutex The mutex 148 */ 149APR_DECLARE(void) apr_allocator_mutex_set(apr_allocator_t *allocator, 150 apr_thread_mutex_t *mutex) 151 __attribute__((nonnull(1))); 152 153/** 154 * Get the mutex currently set for the allocator 155 * @param allocator The allocator 156 */ 157APR_DECLARE(apr_thread_mutex_t *) apr_allocator_mutex_get( 158 apr_allocator_t *allocator) 159 __attribute__((nonnull(1))); 160 161#endif /* APR_HAS_THREADS */ 162 163/** @} */ 164 165#ifdef __cplusplus 166} 167#endif 168 169#endif /* !APR_ALLOCATOR_H */ 170