source/core/semaphore.cpp

   1 /* $Id$
   2
   3 This file is part of libmspcore
   4 Copyright © 2006  Mikko Rasa, Mikkosoft Productions
   5 Distributed under the LGPL
   6 */
   7
   8 #ifdef WIN32
   9 #include <windows.h>
  10 #else
  11 #include <sys/time.h>
  12 #include <cerrno>
  13 #endif
  14 #include <msp/time/timestamp.h>
  15 #include <msp/time/units.h>
  16 #include <msp/time/utils.h>
  17 #include "mutex_private.h"
  18 #include "semaphore.h"
  19 #include "systemerror.h"
  20
  21 namespace Msp {
  22
  23 struct Semaphore::Private
  24 {
  25 #ifdef WIN32
  26         HANDLE handle;
  27 #else
  28         Mutex mutex;
  29         pthread_cond_t cond;
  30         unsigned limit;
  31         unsigned count;
  32 #endif
  33 };
  34
  35
  36 Semaphore::Semaphore(unsigned limit):
  37         priv(new Private)
  38 {
  39 #ifdef WIN32
  40         priv->handle = CreateSemaphore(0, 0, limit, 0);
  41 #else
  42         pthread_cond_init(&priv->cond, 0);
  43         priv->limit = limit;
  44         priv->count = 0;
  45 #endif
  46 }
  47
  48 Semaphore::~Semaphore()
  49 {
  50 #ifdef WIN32
  51         CloseHandle(priv->handle);
  52 #else
  53         pthread_cond_destroy(&priv->cond);
  54 #endif
  55         delete priv;
  56 }
  57
  58 void Semaphore::signal()
  59 {
  60 #ifdef WIN32
  61         if(!ReleaseSemaphore(priv->handle, 1, 0))
  62                 throw system_error("Semaphore::signal");
  63 #else
  64         MutexLock mlock(priv->mutex);
  65         if(priv->count<priv->limit)
  66                 ++priv->count;
  67         if(int err = pthread_cond_signal(&priv->cond))
  68                 throw system_error("Semaphore::signal", err);
  69 #endif
  70 }
  71
  72 void Semaphore::wait()
  73 {
  74 #ifdef WIN32
  75         DWORD ret = WaitForSingleObject(priv->handle, INFINITE);
  76         if(ret==WAIT_FAILED)
  77                 throw system_error("Semaphore::wait");
  78 #else
  79         MutexLock mlock(priv->mutex);
  80         while(!priv->count)
  81                 if(int err = pthread_cond_wait(&priv->cond, &priv->mutex.priv->mutex))
  82                         throw system_error("Semaphore::wait", err);
  83         --priv->count;
  84 #endif
  85 }
  86
  87 bool Semaphore::wait(const Time::TimeDelta &d)
  88 {
  89 #ifdef WIN32
  90         DWORD ret = WaitForSingleObject(priv->handle, (DWORD)(d/Time::usec));
  91         if(ret==WAIT_FAILED)
  92                 throw system_error("Semaphore::wait");
  93         return ret==WAIT_OBJECT_0;
  94 #else
  95         timespec timeout = Time::now()+d;
  96
  97         int err = pthread_cond_timedwait(&priv->cond, &priv->mutex.priv->mutex, &timeout);
  98         if(err && err!=ETIMEDOUT)
  99                 throw system_error("Semaphore::wait", err);
 100         return err==0;
 101 #endif
 102 }
 103
 104 } // namespace Msp