add cpp timer

Author: double-free

cpptimer/Makefile

@@ -0,0 +1,24 @@
+
+    ###########################################
+    #Makefile for simple programs
+    ###########################################
+INC=
+LIB=
+CC=g++ -std=c++0x
+# display all warnings
+CC_FLAG=-Wall
+
+PRG=timer_test
+OBJ=test.o
+
+$(PRG):$(OBJ)
+	$(CC) $(INC) $(LIB) -o $@ $(OBJ)
+
+.SUFFIXES: .c .o .cpp
+.cpp.o:
+	$(CC) $(CC_FLAG) $(INC) -c $*.cpp -o $*.o
+
+.PRONY:clean
+clean:
+	@echo "Removing linked and compiled files......"
+	rm -f $(OBJ) $(PRG)

cpptimer/test.cpp

@@ -0,0 +1,25 @@
+#include <thread>
+#include <cassert>
+#include "timer.h"
+
+bool test_return() {
+	auto f = [](size_t n) -> int {
+		std::this_thread::sleep_for(std::chrono::milliseconds(n));
+		return 0;
+	};
+	return utility::with_timer(f, 5) == 0;
+}
+
+bool test_void() {
+	auto f = [](size_t n) {
+		std::this_thread::sleep_for(std::chrono::milliseconds(n));
+	};
+	utility::with_timer(f, 5);
+	return true;
+}
+
+int main(int argc, char* argv[]) {
+	assert(test_return());
+	assert(test_void());
+    return 0;
+}

cpptimer/timer.h

@@ -0,0 +1,27 @@
+#include <chrono>
+#include <iostream>
+
+namespace utility {
+// avoid to work around function with a *void* return value
+// use constructor-destructor to calculate time
+class TimePrinter {
+private:
+  std::chrono::steady_clock::time_point start_;
+
+public:
+  TimePrinter() : start_(std::chrono::steady_clock::now()) {}
+  ~TimePrinter() {
+    auto end = std::chrono::steady_clock::now();
+    std::chrono::duration<double> time_span =
+        std::chrono::duration_cast<std::chrono::duration<double>>(end - start_);
+    std::cout << time_span.count() << " seconds elapsed" << std::endl;
+  }
+};
+
+template <typename Func, typename... Args>
+auto with_timer(Func f, Args &&... args)
+    -> decltype(f(std::forward<Args>(args)...)) {
+  TimePrinter p;
+  return f(std::forward<Args>(args)...);
+}
+}