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authorMartin Lucina <martin@lucina.net>2012-01-23 08:53:19 +0100
committerMartin Lucina <martin@lucina.net>2012-01-23 08:53:19 +0100
commita15854bd92db69fcd0b4444fe1b8fe3610a7acf6 (patch)
tree1214b945d0f0033ff318de367c70525ea141ef56 /src/atomic_ptr.hpp
Imported Upstream version 2.0.7.dfsgupstream/2.0.7.dfsg
Diffstat (limited to 'src/atomic_ptr.hpp')
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+/*
+ 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_PTR_HPP_INCLUDED__
+#define __ZMQ_ATOMIC_PTR_HPP_INCLUDED__
+
+#include "platform.hpp"
+
+#if defined ZMQ_FORCE_MUTEXES
+#define ZMQ_ATOMIC_PTR_MUTEX
+#elif (defined __i386__ || defined __x86_64__) && defined __GNUC__
+#define ZMQ_ATOMIC_PTR_X86
+#elif defined ZMQ_HAVE_WINDOWS
+#define ZMQ_ATOMIC_PTR_WINDOWS
+#elif (defined ZMQ_HAVE_SOLARIS || defined ZMQ_HAVE_NETBSD)
+#define ZMQ_ATOMIC_PTR_ATOMIC_H
+#else
+#define ZMQ_ATOMIC_PTR_MUTEX
+#endif
+
+#if defined ZMQ_ATOMIC_PTR_MUTEX
+#include "mutex.hpp"
+#elif defined ZMQ_ATOMIC_PTR_WINDOWS
+#include "windows.hpp"
+#elif defined ZMQ_ATOMIC_PTR_ATOMIC_H
+#include <atomic.h>
+#endif
+
+namespace zmq
+{
+
+ // This class encapsulates several atomic operations on pointers.
+
+ template <typename T> class atomic_ptr_t
+ {
+ public:
+
+ // Initialise atomic pointer
+ inline atomic_ptr_t ()
+ {
+ ptr = NULL;
+ }
+
+ // Destroy atomic pointer
+ inline ~atomic_ptr_t ()
+ {
+ }
+
+ // Set value of atomic pointer in a non-threadsafe way
+ // Use this function only when you are sure that at most one
+ // thread is accessing the pointer at the moment.
+ inline void set (T *ptr_)
+ {
+ this->ptr = ptr_;
+ }
+
+ // Perform atomic 'exchange pointers' operation. Pointer is set
+ // to the 'val' value. Old value is returned.
+ inline T *xchg (T *val_)
+ {
+#if defined ZMQ_ATOMIC_PTR_WINDOWS
+ return (T*) InterlockedExchangePointer ((PVOID*) &ptr, val_);
+#elif defined ZMQ_ATOMIC_PTR_ATOMIC_H
+ return (T*) atomic_swap_ptr (&ptr, val_);
+#elif defined ZMQ_ATOMIC_PTR_X86
+ T *old;
+ __asm__ volatile (
+ "lock; xchg %0, %2"
+ : "=r" (old), "=m" (ptr)
+ : "m" (ptr), "0" (val_));
+ return old;
+#elif defined ZMQ_ATOMIC_PTR_MUTEX
+ sync.lock ();
+ T *old = (T*) ptr;
+ ptr = val_;
+ sync.unlock ();
+ return old;
+#else
+#error atomic_ptr is not implemented for this platform
+#endif
+ }
+
+ // Perform atomic 'compare and swap' operation on the pointer.
+ // The pointer is compared to 'cmp' argument and if they are
+ // equal, its value is set to 'val'. Old value of the pointer
+ // is returned.
+ inline T *cas (T *cmp_, T *val_)
+ {
+#if defined ZMQ_ATOMIC_PTR_WINDOWS
+ return (T*) InterlockedCompareExchangePointer (
+ (volatile PVOID*) &ptr, val_, cmp_);
+#elif defined ZMQ_ATOMIC_PTR_ATOMIC_H
+ return (T*) atomic_cas_ptr (&ptr, cmp_, val_);
+#elif defined ZMQ_ATOMIC_PTR_X86
+ T *old;
+ __asm__ volatile (
+ "lock; cmpxchg %2, %3"
+ : "=a" (old), "=m" (ptr)
+ : "r" (val_), "m" (ptr), "0" (cmp_)
+ : "cc");
+ return old;
+#elif defined ZMQ_ATOMIC_PTR_MUTEX
+ sync.lock ();
+ T *old = (T*) ptr;
+ if (ptr == cmp_)
+ ptr = val_;
+ sync.unlock ();
+ return old;
+#else
+#error atomic_ptr is not implemented for this platform
+#endif
+ }
+
+ private:
+
+ volatile T *ptr;
+#if defined ZMQ_ATOMIC_PTR_MUTEX
+ mutex_t sync;
+#endif
+
+ atomic_ptr_t (const atomic_ptr_t&);
+ void operator = (const atomic_ptr_t&);
+ };
+
+}
+
+// Remove macros local to this file.
+#if defined ZMQ_ATOMIC_PTR_WINDOWS
+#undef ZMQ_ATOMIC_PTR_WINDOWS
+#endif
+#if defined ZMQ_ATOMIC_PTR_ATOMIC_H
+#undef ZMQ_ATOMIC_PTR_ATOMIC_H
+#endif
+#if defined ZMQ_ATOMIC_PTR_X86
+#undef ZMQ_ATOMIC_PTR_X86
+#endif
+#if defined ZMQ_ATOMIC_PTR_MUTEX
+#undef ZMQ_ATOMIC_PTR_MUTEX
+#endif
+
+#endif
+