Atomic.h

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// Atomic Types type -*- C++ -*-
/*
Galois, a framework to exploit amorphous data-parallelism in irregular
programs.

Copyright (C) 2011, The University of Texas at Austin. All rights reserved.
UNIVERSITY EXPRESSLY DISCLAIMS ANY AND ALL WARRANTIES CONCERNING THIS SOFTWARE
AND DOCUMENTATION, INCLUDING ANY WARRANTIES OF MERCHANTABILITY, FITNESS FOR ANY
PARTICULAR PURPOSE, NON-INFRINGEMENT AND WARRANTIES OF PERFORMANCE, AND ANY
WARRANTY THAT MIGHT OTHERWISE ARISE FROM COURSE OF DEALING OR USAGE OF TRADE.
NO WARRANTY IS EITHER EXPRESS OR IMPLIED WITH RESPECT TO THE USE OF THE
SOFTWARE OR DOCUMENTATION. Under no circumstances shall University be liable
for incidental, special, indirect, direct or consequential damages or loss of
profits, interruption of business, or related expenses which may arise from use
of Software or Documentation, including but not limited to those resulting from
defects in Software and/or Documentation, or loss or inaccuracy of data of any
kind.
*/

#ifndef _GALOIS_UTIL_ATOMIC_H
#define _GALOIS_UTIL_ATOMIC_H

namespace Galois {


template<typename T>
class GAtomic {
  T val;

public:
  explicit GAtomic(const T& i) :val(i) {}
  T operator+=(const T& rhs) {
    return __sync_add_and_fetch(&val, rhs); 
  }
  T operator-=(const T& rhs) {
    return __sync_sub_and_fetch(&val, rhs); 
  }
  T operator++() {
    return __sync_add_and_fetch(&val, 1);
  }
  T operator++(int) {
    return __sync_fetch_and_add(&val, 1);
  }
  T operator--() { 
    return __sync_sub_and_fetch(&val, 1); 
  }
  T operator--(int) {
    return __sync_fetch_and_sub(&val, 1);
  }
  operator T() const {
    return val;
  }
  T operator=(const T& i) {
    val = i;
    return i;
  }
  T operator=(const GAtomic& i) {
    T iv = (T)i;
    val = iv;
    return iv;
  }
  bool cas (const T& expected, const T& updated) {
    return __sync_bool_compare_and_swap (&val, expected, updated);
  }
};

template<>
class GAtomic<bool> {
  bool val;
public:
  explicit GAtomic(bool i) :val(i) {}

  operator bool() const {
    return val;
  }

  bool operator=(bool i) {
    val = i;
    return i;
  }
  bool operator=(const GAtomic<bool>& i) {
    bool iv = (bool)i;
    val = iv;
    return iv;
  }
  bool cas (bool expected, bool updated) {
    return __sync_bool_compare_and_swap (&val, expected, updated);
  }
};

}



#endif //  _GALOIS_UTIL_ATOMIC_H

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