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Diffstat (limited to 'src/atomic_counter.hpp')
| -rw-r--r-- | src/atomic_counter.hpp | 163 |
1 files changed, 163 insertions, 0 deletions
diff --git a/src/atomic_counter.hpp b/src/atomic_counter.hpp new file mode 100644 index 0000000..b446627 --- /dev/null +++ b/src/atomic_counter.hpp @@ -0,0 +1,163 @@ +/* + Copyright (c) 2007-2010 iMatix Corporation + + This file is part of 0MQ. + + 0MQ is free software; you can redistribute it and/or modify it under + the terms of the Lesser GNU General Public License as published by + the Free Software Foundation; either version 3 of the License, or + (at your option) any later version. + + 0MQ is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + Lesser GNU General Public License for more details. + + You should have received a copy of the Lesser GNU General Public License + along with this program. If not, see <http://www.gnu.org/licenses/>. +*/ + +#ifndef __ZMQ_ATOMIC_COUNTER_HPP_INCLUDED__ +#define __ZMQ_ATOMIC_COUNTER_HPP_INCLUDED__ + +#include "stdint.hpp" +#include "platform.hpp" + +#if defined ZMQ_FORCE_MUTEXES +#define ZMQ_ATOMIC_COUNTER_MUTEX +#elif (defined __i386__ || defined __x86_64__) && defined __GNUC__ +#define ZMQ_ATOMIC_COUNTER_X86 +#elif defined ZMQ_HAVE_WINDOWS +#define ZMQ_ATOMIC_COUNTER_WINDOWS +#elif (defined ZMQ_HAVE_SOLARIS || defined ZMQ_HAVE_NETBSD) +#define ZMQ_ATOMIC_COUNTER_ATOMIC_H +#else +#define ZMQ_ATOMIC_COUNTER_MUTEX +#endif + +#if defined ZMQ_ATOMIC_COUNTER_MUTEX +#include "mutex.hpp" +#elif defined ZMQ_ATOMIC_COUNTER_WINDOWS +#include "windows.hpp" +#elif defined ZMQ_ATOMIC_COUNTER_ATOMIC_H +#include <atomic.h> +#endif + +namespace zmq +{ + + // This class represents an integer that can be incremented/decremented + // in atomic fashion. + + class atomic_counter_t + { + public: + + typedef uint32_t integer_t; + + inline atomic_counter_t (integer_t value_ = 0) : + value (value_) + { + } + + inline ~atomic_counter_t () + { + } + + // Set counter value (not thread-safe). + inline void set (integer_t value_) + { + value = value_; + } + + // Atomic addition. Returns the old value. + inline integer_t add (integer_t increment_) + { + integer_t old_value; + +#if defined ZMQ_ATOMIC_COUNTER_WINDOWS + old_value = InterlockedExchangeAdd ((LONG*) &value, increment_); +#elif defined ZMQ_ATOMIC_COUNTER_ATOMIC_H + integer_t new_value = atomic_add_32_nv (&value, increment_); + old_value = new_value - increment_; +#elif defined ZMQ_ATOMIC_COUNTER_X86 + __asm__ volatile ( + "lock; xadd %0, %1 \n\t" + : "=r" (old_value), "=m" (value) + : "0" (increment_), "m" (value) + : "cc", "memory"); +#elif defined ZMQ_ATOMIC_COUNTER_MUTEX + sync.lock (); + old_value = value; + value += increment_; + sync.unlock (); +#else +#error atomic_counter is not implemented for this platform +#endif + return old_value; + } + + // Atomic subtraction. Returns false if the counter drops to zero. + inline bool sub (integer_t decrement) + { +#if defined ZMQ_ATOMIC_COUNTER_WINDOWS + LONG delta = - ((LONG) decrement); + integer_t old = InterlockedExchangeAdd ((LONG*) &value, delta); + return old - decrement != 0; +#elif defined ZMQ_ATOMIC_COUNTER_ATOMIC_H + int32_t delta = - ((int32_t) decrement); + integer_t nv = atomic_add_32_nv (&value, delta); + return nv != 0; +#elif defined ZMQ_ATOMIC_COUNTER_X86 + integer_t oldval = -decrement; + volatile integer_t *val = &value; + __asm__ volatile ("lock; xaddl %0,%1" + : "=r" (oldval), "=m" (*val) + : "0" (oldval), "m" (*val) + : "cc", "memory"); + return oldval != decrement; +#elif defined ZMQ_ATOMIC_COUNTER_MUTEX + sync.lock (); + value -= decrement; + bool result = value ? true : false; + sync.unlock (); + return result; +#else +#error atomic_counter is not implemented for this platform +#endif + } + + inline integer_t get () + { + return value; + } + + private: + + volatile integer_t value; +#if defined ZMQ_ATOMIC_COUNTER_MUTEX + mutex_t sync; +#endif + + atomic_counter_t (const atomic_counter_t&); + void operator = (const atomic_counter_t&); + }; + +} + +// Remove macros local to this file. +#if defined ZMQ_ATOMIC_COUNTER_WINDOWS +#undef ZMQ_ATOMIC_COUNTER_WINDOWS +#endif +#if defined ZMQ_ATOMIC_COUNTER_ATOMIC_H +#undef ZMQ_ATOMIC_COUNTER_ATOMIC_H +#endif +#if defined ZMQ_ATOMIC_COUNTER_X86 +#undef ZMQ_ATOMIC_COUNTER_X86 +#endif +#if defined ZMQ_ATOMIC_COUNTER_MUTEX +#undef ZMQ_ATOMIC_COUNTER_MUTEX +#endif + +#endif + |