Remove system_time(), replace entirely with std::chrono.

Only remaining use of time.h/ctime is to convert from a time point to
a calendar value, which still requires C's gmtime. Hide it entirely in
time.cpp and return a calendar_point struct instead of a std::tm.

2 files changed, 33 insertions, 16 deletions

diff --git a/src/utils/time.cpp b/src/utils/time.cpp
index 856b1c7be..1c64c820e 100644
--- a/src/utils/time.cpp
+++ b/src/utils/time.cpp
@@ -45,25 +45,30 @@ u64bit combine_timers(u32bit seconds, u32bit parts, u32bit parts_hz)
 
 }
 
-/**
-* Get the system clock
-*/
-u64bit system_time()
-   {
-   return static_cast<u64bit>(std::time(0));
-   }
-
 /*
 * Convert a time_t to a struct tm
 */
-std::tm time_t_to_tm(u64bit timer)
+calendar_point calendar_value(
+   const std::chrono::system_clock::time_point& time_point)
    {
-   std::time_t time_val = static_cast<std::time_t>(timer);
+   time_t time_val = std::chrono::system_clock::to_time_t(time_point);
+
+   // Race condition: std::gmtime is not assured thread safe,
+   // and C++ does not include gmtime_r. Use a mutex here?
 
    std::tm* tm_p = std::gmtime(&time_val);
    if (tm_p == 0)
       throw Encoding_Error("time_t_to_tm could not convert");
-   return (*tm_p);
+
+   std::tm tm = *tm_p;
+   // Race is over here
+
+   return calendar_point(tm.tm_year + 1900,
+                         tm.tm_mon + 1,
+                         tm.tm_mday,
+                         tm.tm_hour,
+                         tm.tm_min,
+                         tm.tm_sec);
    }
 
 u64bit get_nanoseconds_clock()
diff --git a/src/utils/time.h b/src/utils/time.h
index c7f459096..28b777efe 100644
--- a/src/utils/time.h
+++ b/src/utils/time.h
@@ -9,16 +9,28 @@
 #define BOTAN_TIME_H__
 
 #include <botan/types.h>
-#include <ctime>
+#include <chrono>
 
 namespace Botan {
 
 /*
-* Time Access/Conversion Functions
+* Time Conversion Functions
 */
-BOTAN_DLL u64bit system_time();
-
-BOTAN_DLL std::tm time_t_to_tm(u64bit);
+struct BOTAN_DLL calendar_point
+   {
+   u32bit year;
+   byte month;
+   byte day;
+   byte hour;
+   byte minutes;
+   byte seconds;
+
+   calendar_point(u32bit y, byte mon, byte d, byte h, byte min, byte sec) :
+      year(y), month(mon), day(d), hour(h), minutes(min), seconds(sec) {}
+   };
+
+BOTAN_DLL calendar_point calendar_value(
+   const std::chrono::system_clock::time_point& time_point);
 
 /**
 @return nanoseconds resolution timestamp, unknown epoch