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apr_allocator.h

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00001 /* Copyright 2000-2004 The Apache Software Foundation 00002 * 00003 * Licensed under the Apache License, Version 2.0 (the "License"); 00004 * you may not use this file except in compliance with the License. 00005 * You may obtain a copy of the License at 00006 * 00007 * http://www.apache.org/licenses/LICENSE-2.0 00008 * 00009 * Unless required by applicable law or agreed to in writing, software 00010 * distributed under the License is distributed on an "AS IS" BASIS, 00011 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 00012 * See the License for the specific language governing permissions and 00013 * limitations under the License. 00014 */ 00015 00016 #ifndef APR_ALLOCATOR_H 00017 #define APR_ALLOCATOR_H 00018 00019 /** 00020 * @file apr_allocator.h 00021 * @brief APR Internal Memory Allocation 00022 */ 00023 00024 #include "apr.h" 00025 #include "apr_errno.h" 00026 #define APR_WANT_MEMFUNC /**< For no good reason? */ 00027 #include "apr_want.h" 00028 00029 #ifdef __cplusplus 00030 extern "C" { 00031 #endif 00032 00033 /** 00034 * @defgroup apr_allocator Internal Memory Allocation 00035 * @ingroup APR 00036 * @{ 00037 */ 00038 00039 /** the allocator structure */ 00040 typedef struct apr_allocator_t apr_allocator_t; 00041 /** the structure which holds information about the allocation */ 00042 typedef struct apr_memnode_t apr_memnode_t; 00043 00044 /** basic memory node structure 00045 * @note The next, ref and first_avail fields are available for use by the 00046 * caller of apr_allocator_alloc(), the remaining fields are read-only. 00047 * The next field has to be used with caution and sensibly set when the 00048 * memnode is passed back to apr_allocator_free(). See apr_allocator_free() 00049 * for details. 00050 * The ref and first_avail fields will be properly restored by 00051 * apr_allocator_free(). 00052 */ 00053 struct apr_memnode_t { 00054 apr_memnode_t *next; /**< next memnode */ 00055 apr_memnode_t **ref; /**< reference to self */ 00056 apr_uint32_t index; /**< size */ 00057 apr_uint32_t free_index; /**< how much free */ 00058 char *first_avail; /**< pointer to first free memory */ 00059 char *endp; /**< pointer to end of free memory */ 00060 }; 00061 00062 /** The base size of a memory node - aligned. */ 00063 #define APR_MEMNODE_T_SIZE APR_ALIGN_DEFAULT(sizeof(apr_memnode_t)) 00064 00065 /** Symbolic constants */ 00066 #define APR_ALLOCATOR_MAX_FREE_UNLIMITED 0 00067 00068 /** 00069 * Create a new allocator 00070 * @param allocator The allocator we have just created. 00071 * 00072 */ 00073 APR_DECLARE(apr_status_t) apr_allocator_create(apr_allocator_t **allocator); 00074 00075 /** 00076 * Destroy an allocator 00077 * @param allocator The allocator to be destroyed 00078 * @remark Any memnodes not given back to the allocator prior to destroying 00079 * will _not_ be free()d. 00080 */ 00081 APR_DECLARE(void) apr_allocator_destroy(apr_allocator_t *allocator); 00082 00083 /** 00084 * Allocate a block of mem from the allocator 00085 * @param allocator The allocator to allocate from 00086 * @param size The size of the mem to allocate (excluding the 00087 * memnode structure) 00088 */ 00089 APR_DECLARE(apr_memnode_t *) apr_allocator_alloc(apr_allocator_t *allocator, 00090 apr_size_t size); 00091 00092 /** 00093 * Free a list of blocks of mem, giving them back to the allocator. 00094 * The list is typically terminated by a memnode with its next field 00095 * set to NULL. 00096 * @param allocator The allocator to give the mem back to 00097 * @param memnode The memory node to return 00098 */ 00099 APR_DECLARE(void) apr_allocator_free(apr_allocator_t *allocator, 00100 apr_memnode_t *memnode); 00101 00102 #include "apr_pools.h" 00103 00104 /** 00105 * Set the owner of the allocator 00106 * @param allocator The allocator to set the owner for 00107 * @param pool The pool that is to own the allocator 00108 * @remark Typically pool is the highest level pool using the allocator 00109 */ 00110 /* 00111 * XXX: see if we can come up with something a bit better. Currently 00112 * you can make a pool an owner, but if the pool doesn't use the allocator 00113 * the allocator will never be destroyed. 00114 */ 00115 APR_DECLARE(void) apr_allocator_owner_set(apr_allocator_t *allocator, 00116 apr_pool_t *pool); 00117 00118 /** 00119 * Get the current owner of the allocator 00120 * @param allocator The allocator to get the owner from 00121 */ 00122 APR_DECLARE(apr_pool_t *) apr_allocator_owner_get(apr_allocator_t *allocator); 00123 00124 /** 00125 * Set the current threshold at which the allocator should start 00126 * giving blocks back to the system. 00127 * @param allocator The allocator the set the threshold on 00128 * @param size The threshold. 0 == unlimited. 00129 */ 00130 APR_DECLARE(void) apr_allocator_max_free_set(apr_allocator_t *allocator, 00131 apr_size_t size); 00132 00133 #include "apr_thread_mutex.h" 00134 00135 #if APR_HAS_THREADS 00136 /** 00137 * Set a mutex for the allocator to use 00138 * @param allocator The allocator to set the mutex for 00139 * @param mutex The mutex 00140 */ 00141 APR_DECLARE(void) apr_allocator_mutex_set(apr_allocator_t *allocator, 00142 apr_thread_mutex_t *mutex); 00143 00144 /** 00145 * Get the mutex currently set for the allocator 00146 * @param allocator The allocator 00147 */ 00148 APR_DECLARE(apr_thread_mutex_t *) apr_allocator_mutex_get( 00149 apr_allocator_t *allocator); 00150 00151 #endif /* APR_HAS_THREADS */ 00152 00153 /** @} */ 00154 00155 #ifdef __cplusplus 00156 } 00157 #endif 00158 00159 #endif /* !APR_ALLOCATOR_H */

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