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 31 extern "C" { 32 #endif 33 34 /** 35 * @defgroup apr_allocator Internal Memory Allocation 36 * @ingroup APR 37 * @{ 38 */ 39 40 /** the allocator structure */ 41 typedef struct apr_allocator_t apr_allocator_t; 42 /** the structure which holds information about the allocation */ 43 typedef 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 */ 54 struct 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 */ 74 APR_DECLARE(apr_status_t) apr_allocator_create(apr_allocator_t **allocator); 75 76 /** 77 * Destroy an allocator 78 * @param allocator The allocator to be destroyed 79 * @remark Any memnodes not given back to the allocator prior to destroying 80 * will _not_ be free()d. 81 */ 82 APR_DECLARE(void) apr_allocator_destroy(apr_allocator_t *allocator); 83 84 /** 85 * Allocate a block of mem from the allocator 86 * @param allocator The allocator to allocate from 87 * @param size The size of the mem to allocate (excluding the 88 * memnode structure) 89 */ 90 APR_DECLARE(apr_memnode_t *) apr_allocator_alloc(apr_allocator_t *allocator, 91 apr_size_t size); 92 93 /** 94 * Free a list of blocks of mem, giving them back to the allocator. 95 * The list is typically terminated by a memnode with its next field 96 * set to NULL. 97 * @param allocator The allocator to give the mem back to 98 * @param memnode The memory node to return 99 */ 100 APR_DECLARE(void) apr_allocator_free(apr_allocator_t *allocator, 101 apr_memnode_t *memnode); 102 103 #include "apr_pools.h" 104 105 /** 106 * Set the owner of the allocator 107 * @param allocator The allocator to set the owner for 108 * @param pool The pool that is to own the allocator 109 * @remark Typically pool is the highest level pool using the allocator 110 */ 111 /* 112 * XXX: see if we can come up with something a bit better. Currently 113 * you can make a pool an owner, but if the pool doesn't use the allocator 114 * the allocator will never be destroyed. 115 */ 116 APR_DECLARE(void) apr_allocator_owner_set(apr_allocator_t *allocator, 117 apr_pool_t *pool); 118 119 /** 120 * Get the current owner of the allocator 121 * @param allocator The allocator to get the owner from 122 */ 123 APR_DECLARE(apr_pool_t *) apr_allocator_owner_get(apr_allocator_t *allocator); 124 125 /** 126 * Set the current threshold at which the allocator should start 127 * giving blocks back to the system. 128 * @param allocator The allocator the set the threshold on 129 * @param size The threshold. 0 == unlimited. 130 */ 131 APR_DECLARE(void) apr_allocator_max_free_set(apr_allocator_t *allocator, 132 apr_size_t size); 133 134 #include "apr_thread_mutex.h" 135 136 #if APR_HAS_THREADS 137 /** 138 * Set a mutex for the allocator to use 139 * @param allocator The allocator to set the mutex for 140 * @param mutex The mutex 141 */ 142 APR_DECLARE(void) apr_allocator_mutex_set(apr_allocator_t *allocator, 143 apr_thread_mutex_t *mutex); 144 145 /** 146 * Get the mutex currently set for the allocator 147 * @param allocator The allocator 148 */ 149 APR_DECLARE(apr_thread_mutex_t *) apr_allocator_mutex_get( 150 apr_allocator_t *allocator); 151 152 #endif /* APR_HAS_THREADS */ 153 154 /** @} */ 155 156 #ifdef __cplusplus 157 } 158 #endif 159 160 #endif /* !APR_ALLOCATOR_H */ 161