cache sprintf of time in default formatter

example/example.cpp

@@ -48,20 +48,26 @@ void testlog(int threads)
 int main(int argc, char* argv[])
 {
 
+	if(argc || argv){};
     using namespace std::chrono;
     using namespace c11log;
     using namespace utils;
     using std::cout;
     using std::endl;
 
-    //auto fsink2 = std::make_shared<sinks::rotating_file_sink>("log", "txt", 1024*1024*50 , 5, seconds(1));
+    auto fsink = std::make_shared<sinks::rotating_file_sink>("log", "txt", 1024*1024*50 , 5, seconds(1));
     auto &my_logger  = get_logger("example");
+    auto null_sink = std::make_shared<sinks::null_sink>();
+    //auto async = std::make_shared<sinks::async_sink>(1000);
+    //async->add_sink(fsink);
+    my_logger.add_sink(null_sink);
     auto start = system_clock::now();
 
     const unsigned int howmany = 10000000;
     for(unsigned int i = 0; i < howmany ; i++)
         my_logger.info() << "Hello logger " << i;
 	
+	//async->shutdown(seconds(3));
     auto delta = system_clock::now() - start;
     auto delta_d = duration_cast<duration<double>> (delta);
     cout << "Total " << format(howmany) << endl;
@@ -71,7 +77,7 @@ int main(int argc, char* argv[])
 
     return 0;
 
-
+	/*
     if(argc !=3) {
         std::cerr << "Usage: " << argv[0] << " qsize, threads" << std::endl;
         return 0;
@@ -93,5 +99,6 @@ int main(int argc, char* argv[])
 
 
     testlog(threads);
+    */
 }
 

include/c11log/details/os.h

@@ -32,7 +32,20 @@ inline std::tm c11log::details::os::localtime()
     return localtime(now_t);
 }
 
-// Take care of snprintf in visual studio
-#ifdef _MSC_VER
-#define snprintf _snprintf
-#endif
+
+inline bool operator==(const std::tm& tm1, const std::tm& tm2)
+{
+	return (tm1.tm_sec == tm2.tm_sec &&
+		   tm1.tm_min == tm2.tm_min &&
+		   tm1.tm_hour == tm2.tm_hour &&
+		   tm1.tm_mday == tm2.tm_mday &&
+		   tm1.tm_mon == tm2.tm_mon &&
+		   tm1.tm_year == tm2.tm_year &&
+		   tm1.tm_isdst == tm2.tm_isdst &&
+		   tm1.tm_gmtoff == tm2.tm_gmtoff);
+}
+
+inline bool operator!=(const std::tm& tm1, const std::tm& tm2)
+{
+	return !(tm1==tm2);
+}

include/c11log/formatter.h

@@ -43,15 +43,20 @@ private:
 
 inline void c11log::formatters::default_formatter::_format_time(const log_clock::time_point& tp, std::ostream &dest)
 {
-    auto tm = details::os::localtime(log_clock::to_time_t(tp));
-    char buff[64];
-    int size = snprintf(buff, sizeof(buff), "[%d-%02d-%02d %02d:%02d:%02d]",
-                        tm.tm_year + 1900,
-                        tm.tm_mon + 1,
-                        tm.tm_mday,
-                        tm.tm_hour,
-                        tm.tm_min,
-                        tm.tm_sec);
-
-    dest.write(buff, size);
+	static thread_local std::tm last_tm = {0,0,0,0,0,0,0,0,0,0,0};
+	static thread_local char last_time_str[64];
+    auto tm_now = details::os::localtime(log_clock::to_time_t(tp));
+    
+    if(last_tm != tm_now)
+    {				
+		sprintf(last_time_str, "[%d-%02d-%02d %02d:%02d:%02d]",
+                tm_now.tm_year + 1900,
+                tm_now.tm_mon + 1,
+                tm_now.tm_mday,
+                tm_now.tm_hour,
+                tm_now.tm_min,
+                tm_now.tm_sec);
+       	 last_tm = tm_now;			
+	}			
+	dest << last_time_str;	
 }