add PIReadWriteLock, PIReadLocker and PIWriteLocker

main.cpp

@@ -39,28 +39,66 @@ public:
 
 class RWL {
 public:
-	void lockWrite() { mutex.lock(); }
-	void unlockWrite() { mutex.unlock(); }
-	void lockRead() {}
-	void unlockRead() {}
+	void lockWrite() {
+		PIMutexLocker _ml(mutex);
+		while (reading > 0 || writing) {
+			var.wait(mutex);
+		}
+		writing = true;
+	}
+	void unlockWrite() {
+		PIMutexLocker _ml(mutex);
+		writing = false;
+		var.notifyAll();
+	}
+	void lockRead() {
+		PIMutexLocker _ml(mutex);
+		while (writing) {
+			var.wait(mutex);
+		}
+		++reading;
+	}
+	void unlockRead() {
+		PIMutexLocker _ml(mutex);
+		--reading;
+		var.notifyAll();
+	}
+
+private:
+	PIConditionVariable var;
+	int reading  = 0;
+	bool writing = false;
 	PIMutex mutex;
 };
 
 PIMutex mutex;
 PISemaphore sem(10);
+PIReadWriteLock rwl;
 
 int main(int argc, char * argv[]) {
 	/*sem.acquire(2);
 	piCout << sem.tryAcquire(2);
 	piCout << sem.available();
 	return 0;*/
-	PIThread t_w(
+	PIThread t_w0(
 		[] {
 			// PIMutexLocker _ml(mutex);
-			piCout << "write start ...";
+			PIWriteLocker rl(rwl);
+			piCout << "write0 start ...";
 			piMSleep(500);
-			sem.release(11);
-			piCout << "write end" << sem.available() << "\n";
+			piCout << "write0 end"
+				   << "\n";
+		},
+		true,
+		1_Hz);
+	PIThread t_w1(
+		[] {
+			// PIMutexLocker _ml(mutex);
+			PIWriteLocker rl(rwl);
+			piCout << "write1 start ...";
+			piMSleep(500);
+			piCout << "write1 end"
+				   << "\n";
 		},
 		true,
 		1_Hz);
@@ -69,33 +107,36 @@ int main(int argc, char * argv[]) {
 	PIThread t_r0(
 		[&cnt0] {
 			// PIMutexLocker _ml(mutex);
+			PIReadLocker rl(rwl);
 			piCout << "read0 start ...";
 			piMSleep(50);
-			sem.acquire(2);
-			bool ok = true; // sem.tryAcquire(2, 100_ms);
-			if (ok) ++cnt0;
-			piCout << "read0 end" << sem.available() << ok;
+			// bool ok = rwl.tryLockRead(100_ms);
+			// if (ok) ++cnt0;
+			piCout << "read0 end";
+			// if (ok) rwl.unlockRead();
 		},
 		true,
 		10_Hz);
 	PIThread t_r1(
 		[&cnt1] {
 			// PIMutexLocker _ml(mutex);
+			// PIReadLocker rl(rwl);
 			piCout << "read1 start ...";
 			piMSleep(50);
-			sem.acquire(2);
-			bool ok = true; // sem.tryAcquire(2, 100_ms);
+			bool ok = rwl.tryLockRead(100_ms);
 			if (ok) ++cnt1;
-			piCout << "read1 end" << sem.available() << ok;
+			piCout << "read1 end" << ok;
+			if (ok) rwl.unlockRead();
 		},
 		true,
 		11_Hz);
 
-	piSleep(5.);
+	piSleep(8.);
 
 	t_r0.stopAndWait();
 	t_r1.stopAndWait();
-	t_w.stopAndWait();
+	t_w0.stopAndWait();
+	t_w1.stopAndWait();
 
 	piCout << cnt0 << cnt1;