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// -*- mode:C++; tab-width:8; c-basic-offset:2; indent-tabs-mode:t -*-
// vim: ts=8 sw=2 smarttab
/*
* Ceph - scalable distributed file system
*
* Copyright (C) 2004-2011 New Dream Network
*
* This is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License version 2.1, as published by the Free Software
* Foundation. See file COPYING.
*
* @author Sage Weil <sage@newdream.net>
*/
#ifndef CEPH_ATOMIC_H
#define CEPH_ATOMIC_H
#ifdef __CEPH__
# include "acconfig.h"
#endif
#ifndef NO_ATOMIC_OPS
// libatomic_ops implementation
#include <atomic_ops.h>
// reinclude our assert to clobber the system one
#include "include/assert.h"
namespace ceph {
class atomic_t {
AO_t val;
public:
atomic_t(AO_t i=0) : val(i) {}
void set(size_t v) {
AO_store(&val, v);
}
AO_t inc() {
return AO_fetch_and_add1(&val) + 1;
}
AO_t dec() {
return AO_fetch_and_sub1_write(&val) - 1;
}
void add(AO_t add_me) {
AO_fetch_and_add(&val, add_me);
}
void sub(int sub_me) {
int negsub = 0 - sub_me;
AO_fetch_and_add_write(&val, (AO_t)negsub);
}
AO_t read() const {
// cast away const on the pointer. this is only needed to build
// on lenny, but not newer debians, so the atomic_ops.h got fixed
// at some point. this hack can go away someday...
return AO_load_full((AO_t *)&val);
}
private:
// forbid copying
atomic_t(const atomic_t &other);
atomic_t &operator=(const atomic_t &rhs);
};
}
#else
/*
* crappy slow implementation that uses a pthreads spinlock.
*/
#include <pthread.h>
#include "include/assert.h"
namespace ceph {
class atomic_t {
mutable pthread_spinlock_t lock;
signed long val;
public:
atomic_t(int i=0)
: val(i) {
pthread_spin_init(&lock, PTHREAD_PROCESS_PRIVATE);
}
~atomic_t() {
pthread_spin_destroy(&lock);
}
void set(size_t v) {
pthread_spin_lock(&lock);
val = v;
pthread_spin_unlock(&lock);
}
int inc() {
pthread_spin_lock(&lock);
int r = ++val;
pthread_spin_unlock(&lock);
return r;
}
int dec() {
pthread_spin_lock(&lock);
int r = --val;
pthread_spin_unlock(&lock);
return r;
}
void add(int d) {
pthread_spin_lock(&lock);
val += d;
pthread_spin_unlock(&lock);
}
void sub(int d) {
pthread_spin_lock(&lock);
val -= d;
pthread_spin_unlock(&lock);
}
int read() const {
signed long ret;
pthread_spin_lock(&lock);
ret = val;
pthread_spin_unlock(&lock);
return ret;
}
private:
// forbid copying
atomic_t(const atomic_t &other);
atomic_t &operator=(const atomic_t &rhs);
};
}
#endif
#endif
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