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| -rw-r--r-- | include/apr_atomic.h | 207 |
1 files changed, 207 insertions, 0 deletions
diff --git a/include/apr_atomic.h b/include/apr_atomic.h new file mode 100644 index 0000000..3d203ed --- /dev/null +++ b/include/apr_atomic.h @@ -0,0 +1,207 @@ +/* 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 APR_ATOMIC_H +#define APR_ATOMIC_H + +/** + * @file apr_atomic.h + * @brief APR Atomic Operations + */ + +#include "apr.h" +#include "apr_pools.h" + +#ifdef __cplusplus +extern "C" { +#endif + +/** + * @defgroup apr_atomic Atomic Operations + * @ingroup APR + * @{ + */ + +/** + * this function is required on some platforms to initialize the + * atomic operation's internal structures + * @param p pool + * @return APR_SUCCESS on successful completion + * @remark Programs do NOT need to call this directly. APR will call this + * automatically from apr_initialize(). + * @internal + */ +APR_DECLARE(apr_status_t) apr_atomic_init(apr_pool_t *p); + +/* + * Atomic operations on 32-bit values + * Note: Each of these functions internally implements a memory barrier + * on platforms that require it + */ + +/** + * atomically read an apr_uint32_t from memory + * @param mem the pointer + */ +APR_DECLARE(apr_uint32_t) apr_atomic_read32(volatile apr_uint32_t *mem); + +/** + * atomically set an apr_uint32_t in memory + * @param mem pointer to the object + * @param val value that the object will assume + */ +APR_DECLARE(void) apr_atomic_set32(volatile apr_uint32_t *mem, apr_uint32_t val); + +/** + * atomically add 'val' to an apr_uint32_t + * @param mem pointer to the object + * @param val amount to add + * @return old value pointed to by mem + */ +APR_DECLARE(apr_uint32_t) apr_atomic_add32(volatile apr_uint32_t *mem, apr_uint32_t val); + +/** + * atomically subtract 'val' from an apr_uint32_t + * @param mem pointer to the object + * @param val amount to subtract + */ +APR_DECLARE(void) apr_atomic_sub32(volatile apr_uint32_t *mem, apr_uint32_t val); + +/** + * atomically increment an apr_uint32_t by 1 + * @param mem pointer to the object + * @return old value pointed to by mem + */ +APR_DECLARE(apr_uint32_t) apr_atomic_inc32(volatile apr_uint32_t *mem); + +/** + * atomically decrement an apr_uint32_t by 1 + * @param mem pointer to the atomic value + * @return zero if the value becomes zero on decrement, otherwise non-zero + */ +APR_DECLARE(int) apr_atomic_dec32(volatile apr_uint32_t *mem); + +/** + * compare an apr_uint32_t's value with 'cmp'. + * If they are the same swap the value with 'with' + * @param mem pointer to the value + * @param with what to swap it with + * @param cmp the value to compare it to + * @return the old value of *mem + */ +APR_DECLARE(apr_uint32_t) apr_atomic_cas32(volatile apr_uint32_t *mem, apr_uint32_t with, + apr_uint32_t cmp); + +/** + * exchange an apr_uint32_t's value with 'val'. + * @param mem pointer to the value + * @param val what to swap it with + * @return the old value of *mem + */ +APR_DECLARE(apr_uint32_t) apr_atomic_xchg32(volatile apr_uint32_t *mem, apr_uint32_t val); + +/* + * Atomic operations on 64-bit values + * Note: Each of these functions internally implements a memory barrier + * on platforms that require it + */ + +/** + * atomically read an apr_uint64_t from memory + * @param mem the pointer + */ +APR_DECLARE(apr_uint64_t) apr_atomic_read64(volatile apr_uint64_t *mem); + +/** + * atomically set an apr_uint64_t in memory + * @param mem pointer to the object + * @param val value that the object will assume + */ +APR_DECLARE(void) apr_atomic_set64(volatile apr_uint64_t *mem, apr_uint64_t val); + +/** + * atomically add 'val' to an apr_uint64_t + * @param mem pointer to the object + * @param val amount to add + * @return old value pointed to by mem + */ +APR_DECLARE(apr_uint64_t) apr_atomic_add64(volatile apr_uint64_t *mem, apr_uint64_t val); + +/** + * atomically subtract 'val' from an apr_uint64_t + * @param mem pointer to the object + * @param val amount to subtract + */ +APR_DECLARE(void) apr_atomic_sub64(volatile apr_uint64_t *mem, apr_uint64_t val); + +/** + * atomically increment an apr_uint64_t by 1 + * @param mem pointer to the object + * @return old value pointed to by mem + */ +APR_DECLARE(apr_uint64_t) apr_atomic_inc64(volatile apr_uint64_t *mem); + +/** + * atomically decrement an apr_uint64_t by 1 + * @param mem pointer to the atomic value + * @return zero if the value becomes zero on decrement, otherwise non-zero + */ +APR_DECLARE(int) apr_atomic_dec64(volatile apr_uint64_t *mem); + +/** + * compare an apr_uint64_t's value with 'cmp'. + * If they are the same swap the value with 'with' + * @param mem pointer to the value + * @param with what to swap it with + * @param cmp the value to compare it to + * @return the old value of *mem + */ +APR_DECLARE(apr_uint64_t) apr_atomic_cas64(volatile apr_uint64_t *mem, apr_uint64_t with, + apr_uint64_t cmp); + +/** + * exchange an apr_uint64_t's value with 'val'. + * @param mem pointer to the value + * @param val what to swap it with + * @return the old value of *mem + */ +APR_DECLARE(apr_uint64_t) apr_atomic_xchg64(volatile apr_uint64_t *mem, apr_uint64_t val); + +/** + * compare the pointer's value with cmp. + * If they are the same swap the value with 'with' + * @param mem pointer to the pointer + * @param with what to swap it with + * @param cmp the value to compare it to + * @return the old value of the pointer + */ +APR_DECLARE(void*) apr_atomic_casptr(volatile void **mem, void *with, const void *cmp); + +/** + * exchange a pair of pointer values + * @param mem pointer to the pointer + * @param with what to swap it with + * @return the old value of the pointer + */ +APR_DECLARE(void*) apr_atomic_xchgptr(volatile void **mem, void *with); + +/** @} */ + +#ifdef __cplusplus +} +#endif + +#endif /* !APR_ATOMIC_H */ |