From e13940488427cf7e9456bf9123dac5030838e218 Mon Sep 17 00:00:00 2001
From: Alexander Chemeris <Alexander.Chemeris@gmail.com>
Date: Wed, 18 Aug 2010 22:52:33 +0400
Subject: [PATCH] Implementation of Semaphore.

---
 public-trunk/CommonLibs/Threads.cpp |  9 +++++++++
 public-trunk/CommonLibs/Threads.h   | 31 +++++++++++++++++++++++++++++
 2 files changed, 40 insertions(+)

diff --git a/public-trunk/CommonLibs/Threads.cpp b/public-trunk/CommonLibs/Threads.cpp
index df2e3a1..2628ab1 100644
--- a/public-trunk/CommonLibs/Threads.cpp
+++ b/public-trunk/CommonLibs/Threads.cpp
@@ -95,6 +95,15 @@ void Signal::wait(Mutex& wMutex, unsigned timeout) const
 	pthread_cond_timedwait(&mSignal,&wMutex.mMutex,&waitTime);
 }
 
+/** Wait for semaphore to be signaled with timeout.
+* @returns 0 on success, -1 on error or timeout.
+*/
+int ThreadSemaphore::wait(unsigned timeout) const
+{
+	Timeval then(timeout);
+	struct timespec waitTime = then.timespec();
+	return sem_timedwait(&mSem,&waitTime);
+}
 
 void Thread::start(void *(*task)(void*), void *arg)
 {
diff --git a/public-trunk/CommonLibs/Threads.h b/public-trunk/CommonLibs/Threads.h
index 0f12972..4b65215 100644
--- a/public-trunk/CommonLibs/Threads.h
+++ b/public-trunk/CommonLibs/Threads.h
@@ -29,6 +29,7 @@
 #include <pthread.h>
 #include <iostream>
 #include <assert.h>
+#include <semaphore.h>
 
 class Mutex;
 
@@ -120,7 +121,37 @@ class Signal {
 
 };
 
+/** Semaphore */
+class ThreadSemaphore {
 
+	private:
+
+	mutable sem_t mSem;
+
+	public:
+
+	ThreadSemaphore(int pshared = 0, unsigned value = 0) { assert(sem_init(&mSem,pshared,value)!=-1); }
+
+	~ThreadSemaphore() { sem_destroy(&mSem); }
+
+	/** Wait for semaphore to be signaled with timeout.
+	* @returns 0 on success, -1 on error or timeout.
+	*/
+	int wait (unsigned timeout) const;
+
+	/** Wait for semaphore to be signaled infinitely.
+	* @returns 0 on success, -1 on error.
+	*/
+	int wait() const { return sem_wait(&mSem); }
+
+	/** Check if semaphore has been signaled and disarm it.
+	* @returns 0 if semaphore has been signaled, -1 in other cases.
+	*/
+	int trywait() const { return sem_trywait(&mSem); }
+
+	int post() { return sem_post (&mSem); }
+
+};
 
 #define START_THREAD(thread,function,argument) \
 	thread.start((void *(*)(void*))function, (void*)argument);