C++如何使用宏定义来简化代码性能测试 | cpp macro like function to implement a performance profiler

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cpp macro like function to implement a performance profiler

Guide

macro expansions

• name ===> quote as strings "xxx"

• name, name ===> xxx

• a ## b ===> concatenate the preceding and following tokens.

// #name ===>  "xxx"
// name,  ##name ===> xxx

// ##name ===> concatenate
// #name ===>  quote as strings

// a ## b ===>  concatenate the preceding and following tokens.

#define QUOTE(name) #name
#define CONCAT(x,y) x##y   // x ## y   space in ommited

#define MACRO(name)  #name "foo"
#define MACRO2(name) name "foo"
#define MACRO3(name) ##name "foo"

#define CAT(a, ...) a ## __VA_ARGS__

#define IIF(c) CAT(IIF_, c)
#define IIF_0(t, ...) __VA_ARGS__
#define IIF_1(t, ...) t

void macro_demo()
{
	QUOTE(test); // "test"
	CONCAT(test, foo); // testfoo

	MACRO(test); // "test" "foo"
	MACRO2(test);// test "foo"
	MACRO3(test);// test "foo"
}

macro function

define

#define SUM(a,b)  (a+b)

#define MYDEBUG(...)   fprintf(stderr, ##__VA_ARGS__)

usage

int c = SUM(1,2);
MYDEBUG("%d,%d \n",1,2);     /*   Becomes fprintf(stderr,"%d,%d \n",1,2);   */

with class object

define

class profiler {
public:
	profiler(const char* func_name, unsigned int times = 1);
	~profiler();

	void start();
	int stop();

private:
	boost::posix_time::ptime pt1;
	boost::posix_time::ptime pt2;
	const char * m_func_name;
	int m_times = 1;
};

#define ONCE_PROFILER() profiler _profiler_instance##__LINE__(__FUNCTION__)

#define BEGIN_PROFILE_ONE(name) profiler _profiler_##name(#name)
#define BEGIN_PROFILE_TIMES(name,times) profiler _profiler_##name(#name,times)

#define BEGIN_PROFILE(name,...) profiler _profiler_##name(#name, ##__VA_ARGS__)
#define END_PROFILE(name)  _profiler_##name.stop()

usage

void main()
{

BEGIN_PROFILE(LoadImage);

	load_image();

END_PROFILE(LoadImage); 

BEGIN_PROFILE_TIMES(ProcessImageTimes, 100);
//BEGIN_PROFILE(ProcessImageTimes, 100);
	for(int i=0; i<100;i++){
		process_image();
	}
END_PROFILE(ProcessImageTimes);

}

Reference

• C-Preprocessor-tricks,-tips,-and-idioms

History

• 20191010: created.

Copyright

• Post author: kezunlin
• Post link: https://kezunlin.me/post/65dc693d/
• Copyright Notice: All articles in this blog are licensed under CC BY-NC-SA 3.0 unless stating additionally.