| #ifndef QPID_SYS_ATOMICVALUE_MUTEX_H |
| #define QPID_SYS_ATOMICVALUE_MUTEX_H |
| |
| /* |
| * |
| * 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. |
| * |
| */ |
| |
| #if !defined(QPID_SYS_ATOMICVALUE_H) |
| #error "This file should only be included via AtomicValue.h." |
| #endif |
| |
| #include "qpid/sys/Mutex.h" |
| |
| namespace qpid { |
| namespace sys { |
| |
| /** |
| * Atomic value of type T. T must be an integral type of size 1,2,4 or 8 bytes. |
| * All operations are atomic and preform a full memory barrier unless otherwise noted. |
| */ |
| template <class T> |
| class AtomicValue |
| { |
| public: |
| AtomicValue(T init=0) : value(init) {} |
| |
| // Update and return new value. |
| inline T operator+=(T n) { Lock l(lock); return value += n; } |
| inline T operator-=(T n) { Lock l(lock); return value -= n; } |
| inline T operator++() { return *this += 1; } |
| inline T operator--() { return *this -= 1; } |
| |
| // Update and return old value. |
| inline T fetchAndAdd(T n) { Lock l(lock); T old=value; value += n; return old; } |
| inline T fetchAndSub(T n) { Lock l(lock); T old=value; value -= n; return old; } |
| inline T operator++(int) { return fetchAndAdd(1); } |
| inline T operator--(int) { return fetchAndSub(1); } |
| |
| AtomicValue& operator=(T newval) { Lock l(lock); value = newval; return *this; } |
| |
| /** If current value == testval then set to newval. Returns the old value. */ |
| T valueCompareAndSwap(T testval, T newval) { |
| Lock l(lock); |
| T old=value; |
| if (value == testval) value = newval; |
| return old; |
| } |
| |
| /** If current value == testval then set to newval. Returns true if the swap was performed. */ |
| bool boolCompareAndSwap(T testval, T newval) { |
| Lock l(lock); |
| if (value == testval) { value = newval; return true; } |
| return false; |
| } |
| |
| T get() const { Lock l(lock); return value; } |
| |
| private: |
| typedef Mutex::ScopedLock Lock; |
| T value; |
| mutable Mutex lock; |
| }; |
| |
| }} // namespace qpid::sys |
| |
| #endif /*!QPID_SYS_ATOMICVALUE_MUTEX_H*/ |