1                 : /**********************************************************************
       2                 :  * $Id: cpl_atomic_ops.cpp 19884 2010-06-17 22:01:19Z rouault $
       3                 :  *
       4                 :  * Name:     cpl_atomic_ops.cpp
       5                 :  * Project:  CPL - Common Portability Library
       6                 :  * Purpose:  Atomic operation functions.
       7                 :  * Author:   Even Rouault, <even dot rouault at mines dash paris dot org>
       8                 :  *
       9                 :  **********************************************************************
      10                 :  * Copyright (c) 2009, Even Rouault, <even dot rouault at mines dash paris dot org>
      11                 :  *
      12                 :  * Permission is hereby granted, free of charge, to any person obtaining a
      13                 :  * copy of this software and associated documentation files (the "Software"),
      14                 :  * to deal in the Software without restriction, including without limitation
      15                 :  * the rights to use, copy, modify, merge, publish, distribute, sublicense,
      16                 :  * and/or sell copies of the Software, and to permit persons to whom the
      17                 :  * Software is furnished to do so, subject to the following conditions:
      18                 :  * 
      19                 :  * The above copyright notice and this permission notice shall be included
      20                 :  * in all copies or substantial portions of the Software.
      21                 :  * 
      22                 :  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
      23                 :  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
      24                 :  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
      25                 :  * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
      26                 :  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
      27                 :  * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER 
      28                 :  * DEALINGS IN THE SOFTWARE.
      29                 :  ****************************************************************************/
      30                 : 
      31                 : #include "cpl_atomic_ops.h"
      32                 : 
      33                 : #if defined(__MACH__) && defined(__APPLE__)
      34                 : 
      35                 : #include <libkern/OSAtomic.h>
      36                 : 
      37                 : int CPLAtomicAdd(volatile int* ptr, int increment)
      38                 : {
      39                 :   return OSAtomicAdd32(increment, (int*)(ptr));
      40                 : }
      41                 : 
      42                 : #elif defined(_MSC_VER) && (defined(_M_IX86) || defined(_M_X64))
      43                 : 
      44                 : #include <windows.h>
      45                 : 
      46                 : int CPLAtomicAdd(volatile int* ptr, int increment)
      47                 : {
      48                 : #if defined(_MSC_VER) && (_MSC_VER <= 1200)
      49                 :   return InterlockedExchangeAdd((LONG*)(ptr), (LONG)(increment)) + increment;
      50                 : #else
      51                 :   return InterlockedExchangeAdd((volatile LONG*)(ptr), (LONG)(increment)) + increment;
      52                 : #endif
      53                 : }
      54                 : 
      55                 : #elif defined(__MINGW32__) && defined(__i386__)
      56                 : 
      57                 : #include <windows.h>
      58                 : 
      59                 : int CPLAtomicAdd(volatile int* ptr, int increment)
      60                 : {
      61                 :   return InterlockedExchangeAdd((LONG*)(ptr), (LONG)(increment)) + increment;
      62                 : }
      63                 : 
      64                 : #elif defined(__GNUC__) && (defined(__i386__) || defined(__x86_64__))
      65                 : 
      66         8338946 : int CPLAtomicAdd(volatile int* ptr, int increment)
      67                 : {
      68         8338946 :   int temp = increment;
      69                 :   __asm__ __volatile__("lock; xaddl %0,%1"
      70                 :                        : "+r" (temp), "+m" (*ptr)
      71         8338946 :                        : : "memory");
      72         8338946 :   return temp + increment;
      73                 : }
      74                 : 
      75                 : #elif defined(HAVE_GCC_ATOMIC_BUILTINS)
      76                 : /* Starting with GCC 4.1.0, built-in functions for atomic memory access are provided. */
      77                 : /* see http://gcc.gnu.org/onlinedocs/gcc-4.1.0/gcc/Atomic-Builtins.html */
      78                 : /* We use a ./configure test to determine whether this builtins are available */
      79                 : /* as it appears that the GCC 4.1 version used on debian etch is broken when linking */
      80                 : /* such instructions... */
      81                 : int CPLAtomicAdd(volatile int* ptr, int increment)
      82                 : {
      83                 :   if (increment > 0)
      84                 :     return __sync_add_and_fetch(ptr, increment);
      85                 :   else
      86                 :     return __sync_sub_and_fetch(ptr, -increment);
      87                 : }
      88                 : 
      89                 : #elif !defined(CPL_MULTIPROC_PTHREAD)
      90                 : #warning "Needs real lock API to implement properly atomic increment"
      91                 : 
      92                 : /* Dummy implementation */
      93                 : int CPLAtomicAdd(volatile int* ptr, int increment)
      94                 : {
      95                 :     (*ptr) += increment;
      96                 :     return *ptr;
      97                 : }
      98                 : #else
      99                 : 
     100                 : #include "cpl_multiproc.h"
     101                 : 
     102                 : static void *hAtomicOpMutex = NULL;
     103                 : 
     104                 : /* Slow, but safe, implemenation using a mutex */
     105                 : int CPLAtomicAdd(volatile int* ptr, int increment)
     106                 : {
     107                 :     CPLMutexHolder oMutex(&hAtomicOpMutex);
     108                 :     (*ptr) += increment;
     109                 :     return *ptr;
     110                 : }
     111                 : 
     112                 : #endif
     113                 : 
     114                 : #ifndef HAS_CPL_INLINE
     115                 : 
     116                 : int CPLAtomicInc(volatile int* ptr)
     117                 : {
     118                 :     return CPLAtomicAdd(ptr, 1);
     119                 : }
     120                 : 
     121                 : int CPLAtomicDec(volatile int* ptr)
     122                 : {
     123                 :     return CPLAtomicAdd(ptr, -1);
     124                 : }
     125                 : 
     126                 : #endif