libc/time: Implement timegm function

Signed-off-by: Xiang Xiao <xiaoxiang@xiaomi.com>
Change-Id: Id988ae077cf54597b2522546c4309b66416b8b0e

include/time.h

@@ -91,9 +91,10 @@
 
 #define TIME_UTC           1
 
-/* Redirect the timegm */
 
-#define timegm mktime
+/* Redirect the timelocal */
+
+#define timelocal         mktime
 
 /********************************************************************************
  * Public Types
@@ -192,7 +193,9 @@ int clock_gettime(clockid_t clockid, FAR struct timespec *tp);
 int clock_getres(clockid_t clockid, FAR struct timespec *res);
 int timespec_get(FAR struct timespec *t, int b);
 
+time_t timegm(FAR struct tm *tp);
 time_t mktime(FAR struct tm *tp);
+
 FAR struct tm *gmtime(FAR const time_t *timep);
 FAR struct tm *gmtime_r(FAR const time_t *timep, FAR struct tm *result);
 

libs/libc/time/Make.defs

@@ -29,7 +29,7 @@ CSRCS += lib_gethrtime.c
 ifdef CONFIG_LIBC_LOCALTIME
 CSRCS += lib_localtime.c
 else
-CSRCS += lib_mktime.c lib_gmtime.c lib_gmtimer.c
+CSRCS += lib_timegm.c lib_gmtime.c lib_gmtimer.c
 endif
 
 # Add the time directory to the build

libs/libc/time/lib_gmtime.c

@@ -48,9 +48,7 @@ FAR struct tm *gmtime(FAR const time_t *timep)
   return gmtime_r(timep, &tm);
 }
 
-#ifndef CONFIG_LIBC_LOCALTIME
 FAR struct tm *localtime(FAR const time_t *timep)
 {
   return gmtime(timep);
 }
-#endif

libs/libc/time/lib_gmtimer.c

@@ -344,9 +344,7 @@ FAR struct tm *gmtime_r(FAR const time_t *timep, FAR struct tm *result)
   return result;
 }
 
-#ifndef CONFIG_LIBC_LOCALTIME
 FAR struct tm *localtime_r(FAR const time_t *timep, FAR struct tm *result)
 {
   return gmtime_r(timep, result);
 }
-#endif

libs/libc/time/lib_localtime.c

@@ -2604,3 +2604,8 @@ time_t mktime(struct tm * const tmp)
   tzset();
   return time1(tmp, localsub, 0L);
 }
+
+time_t timegm(FAR struct tm *tmp)
+{
+  return time1(tmp, gmtsub, 0L);
+}

libs/libc/time/lib_timegm.c

@@ -1,5 +1,5 @@
 /****************************************************************************
- * libs/libc/time/lib_mktime.c
+ * libs/libc/time/lib_timegm.c
  *
  * Licensed to the Apache Software Foundation (ASF) under one or more
  * contributor license agreements.  See the NOTICE file distributed with
@@ -62,14 +62,14 @@
  ****************************************************************************/
 
 /****************************************************************************
- * Name:  mktime
+ * Name:  timegm
  *
  * Description:
  *   Time conversion (based on the POSIX API)
  *
  ****************************************************************************/
 
-time_t mktime(FAR struct tm *tp)
+time_t timegm(FAR struct tm *tp)
 {
   time_t ret;
   time_t jdn;
@@ -90,3 +90,8 @@ time_t mktime(FAR struct tm *tp)
 
   return ret;
 }
+
+time_t mktime(FAR struct tm *tp)
+{
+  return timegm(tp);
+}