initial commit

src/atomic_counter.hpp

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+/*
+    Copyright (c) 2007-2009 FastMQ Inc.
+
+    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 __ZS_ATOMIC_COUNTER_HPP_INCLUDED__
+#define __ZS_ATOMIC_COUNTER_HPP_INCLUDED__
+
+#include "stdint.hpp"
+#include "platform.hpp"
+
+#if defined ZS_FORCE_MUTEXES
+#define ZS_ATOMIC_COUNTER_MUTEX
+#elif (defined __i386__ || defined __x86_64__) && defined __GNUC__
+#define ZS_ATOMIC_COUNTER_X86
+#elif 0 && defined __sparc__ && defined __GNUC__
+#define ZS_ATOMIC_COUNTER_SPARC
+#elif defined ZS_HAVE_WINDOWS
+#define ZS_ATOMIC_COUNTER_WINDOWS
+#elif defined ZS_HAVE_SOLARIS
+#define ZS_ATOMIC_COUNTER_SOLARIS
+#else
+#define ZS_ATOMIC_COUNTER_MUTEX
+#endif
+
+#if defined ZS_ATOMIC_COUNTER_MUTEX
+#include "mutex.hpp"
+#elif defined ZS_ATOMIC_COUNTER_WINDOWS
+#include "windows.hpp"
+#elif defined ZS_ATOMIC_COUNTER_SOLARIS
+#include <atomic.h>
+#endif
+
+namespace zs
+{
+
+    //  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 ZS_ATOMIC_COUNTER_WINDOWS
+            old_value = InterlockedExchangeAdd ((LONG*) &value, increment_);
+#elif defined ZS_ATOMIC_COUNTER_SOLARIS
+            integer_t new_value = atomic_add_32_nv (&value, increment_);
+            old_value = new_value - increment_;
+#elif defined ZS_ATOMIC_COUNTER_X86
+            __asm__ volatile (
+                "lock; xadd %0, %1          \n\t"
+                : "=r" (old_value), "=m" (value)
+                : "0" (increment_), "m" (value)
+                : "cc", "memory");
+#elif defined ZS_ATOMIC_COUNTER_SPARC
+            integer_t tmp;
+            __asm__ volatile (
+                "ld [%4], %0                \n\t"
+                "1:                         \n\t"
+                "add %0, %3, %1             \n\t"
+                "cas [%4], %0, %1           \n\t"
+                "cmp %0, %1                 \n\t"
+                "bne,a,pn %%icc, 1b         \n\t"
+                "mov %1, %0                 \n\t"
+                : "=&r" (old_value), "=&r" (tmp), "=m" (value)
+                : "r" (increment_), "r" (&value)
+                : "cc", "memory");
+#elif defined ZS_ATOMIC_COUNTER_MUTEX
+            sync.lock ();
+            old_value = value;
+            value += increment_;
+            sync.unlock ();
+#else
+#error
+#endif
+            return old_value;
+        }
+
+        //  Atomic subtraction. Returns false if the counter drops to zero.
+        inline bool sub (integer_t decrement)
+        {
+#if defined ZS_ATOMIC_COUNTER_WINDOWS
+            LONG delta = - ((LONG) decrement);
+            integer_t old = InterlockedExchangeAdd ((LONG*) &value, delta);
+            return old - decrement != 0;
+#elif defined ZS_ATOMIC_COUNTER_SOLARIS
+            int32_t delta = - ((int32_t) decrement);
+            integer_t nv = atomic_add_32_nv (&value, delta);
+            return nv != 0;
+#elif defined ZS_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");
+            return oldval != decrement;
+#elif defined ZS_ATOMIC_COUNTER_SPARC
+            volatile integer_t *val = &value;
+            integer_t tmp;
+            integer_t result;
+            __asm__ volatile(
+                "ld [%4], %1\n\t"
+                "1:\n\t"
+                "add %1, %0, %2\n\t"
+                "cas [%4], %1, %2\n\t"
+                "cmp %1, %2\n\t"
+                "bne,a,pn %%icc, 1b\n\t"
+                "mov %2, %1\n\t"
+                : "+r" (-decrement), "=&r" (tmp), "=&r" (result), "+m" (*val)
+                : "r" (val)
+                : "cc");
+            return result <= decrement;
+#elif defined ZS_ATOMIC_COUNTER_MUTEX
+            sync.lock ();
+            value -= decrement;
+            bool result = value ? true : false;
+            sync.unlock ();
+            return result;
+#else
+#error
+#endif
+        }
+
+        inline integer_t get ()
+        {
+            return value;
+        }
+
+    private:
+
+        volatile integer_t value;
+#if defined ZS_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 ZS_ATOMIC_COUNTER_WINDOWS
+#undef ZS_ATOMIC_COUNTER_WINDOWS
+#endif
+#if defined ZS_ATOMIC_COUNTER_SOLARIS
+#undef ZS_ATOMIC_COUNTER_SOLARIS
+#endif
+#if defined ZS_ATOMIC_COUNTER_X86
+#undef ZS_ATOMIC_COUNTER_X86
+#endif
+#if defined ZS_ATOMIC_COUNTER_SPARC
+#undef ZS_ATOMIC_COUNTER_SPARC
+#endif
+#if defined ZS_ATOMIC_COUNTER_MUTEX
+#undef ZS_ATOMIC_COUNTER_MUTEX
+#endif
+
+#endif