From 0f48449b5e326f4f66e443cbd1a0393ea00433e4 Mon Sep 17 00:00:00 2001
From: Meco Man <920369182@qq.com>
Date: Sun, 18 Jul 2021 14:34:35 +0800
Subject: [PATCH] [timezone] implement timezone

---
 components/libc/Kconfig                     |  4 +-
 components/libc/compilers/common/sys/time.h |  7 ++++
 components/libc/compilers/common/time.c     | 41 +++++++++++++++++----
 3 files changed, 42 insertions(+), 10 deletions(-)

diff --git a/components/libc/Kconfig b/components/libc/Kconfig
index a89b252caa..37a98ba836 100644
--- a/components/libc/Kconfig
+++ b/components/libc/Kconfig
@@ -59,9 +59,9 @@ if RT_USING_LIBC != y
     default y
 endif
 
-config RT_LIBC_FIXED_TIMEZONE
+config RT_LIBC_DEFAULT_TIMEZONE
     depends on (RT_LIBC_USING_TIME || RT_USING_LIBC)
-    int "Manually set a fixed time zone (UTC+)"
+    int "Set the default time zone (UTC+)"
     range -12 12
     default 8
 
diff --git a/components/libc/compilers/common/sys/time.h b/components/libc/compilers/common/sys/time.h
index bb1a9c96fd..4ca665c536 100644
--- a/components/libc/compilers/common/sys/time.h
+++ b/components/libc/compilers/common/sys/time.h
@@ -12,6 +12,7 @@
 #define _SYS_TIME_H_
 
 #include <rtconfig.h>
+#include <rtdef.h>
 #include <time.h>
 
 #ifdef __cplusplus
@@ -98,6 +99,12 @@ int clock_settime (clockid_t clockid, const struct timespec *tp);
 int clock_time_to_tick(const struct timespec *time);
 #endif /* RT_USING_POSIX */
 
+
+/* timezone APIs (Not standard LIBC APIs) */
+void rt_tz_set(rt_int8_t tz);
+rt_int8_t rt_tz_get(void);
+rt_int8_t rt_tz_is_dst(void);
+
 #ifdef __cplusplus
 }
 #endif
diff --git a/components/libc/compilers/common/time.c b/components/libc/compilers/common/time.c
index e79a22b9db..8f4856a330 100644
--- a/components/libc/compilers/common/time.c
+++ b/components/libc/compilers/common/time.c
@@ -18,6 +18,7 @@
  * 2021-02-12     Meco Man     move all of the functions located in <clock_time.c> to this file
  * 2021-03-15     Meco Man     fixed a bug of leaking memory in asctime()
  * 2021-05-01     Meco Man     support fixed timezone
+ * 2021-07-21     Meco Man     implement that change/set timezone APIs
  */
 
 #include "sys/time.h"
@@ -32,10 +33,6 @@
 #define DBG_LVL    DBG_INFO
 #include <rtdbg.h>
 
-#ifndef RT_LIBC_FIXED_TIMEZONE
-#define RT_LIBC_FIXED_TIMEZONE 8 /* UTC+8 */
-#endif
-
 /* seconds per day */
 #define SPD 24*60*60
 
@@ -202,7 +199,7 @@ struct tm *gmtime_r(const time_t *timep, struct tm *r)
     r->tm_mon = i;
     r->tm_mday += work - __spm[i];
 
-    r->tm_isdst = 0;
+    r->tm_isdst = rt_tz_is_dst();
     return r;
 }
 RTM_EXPORT(gmtime_r);
@@ -218,7 +215,7 @@ struct tm* localtime_r(const time_t* t, struct tm* r)
 {
     time_t local_tz;
 
-    local_tz = *t + RT_LIBC_FIXED_TIMEZONE * 3600;
+    local_tz = *t + rt_tz_get() * 3600;
     return gmtime_r(&local_tz, r);
 }
 RTM_EXPORT(localtime_r);
@@ -235,7 +232,7 @@ time_t mktime(struct tm * const t)
     time_t timestamp;
 
     timestamp = timegm(t);
-    timestamp = timestamp - 3600 * RT_LIBC_FIXED_TIMEZONE;
+    timestamp = timestamp - 3600 * rt_tz_get();
     return timestamp;
 }
 RTM_EXPORT(mktime);
@@ -426,7 +423,7 @@ int gettimeofday(struct timeval *tv, struct timezone *tz)
     if(tz != RT_NULL)
     {
         tz->tz_dsttime = DST_NONE;
-        tz->tz_minuteswest = -(RT_LIBC_FIXED_TIMEZONE * 60);
+        tz->tz_minuteswest = -(rt_tz_get() * 60);
     }
 
     if (tv != RT_NULL && get_timeval(tv) == RT_EOK)
@@ -651,3 +648,31 @@ int clock_time_to_tick(const struct timespec *time)
 RTM_EXPORT(clock_time_to_tick);
 
 #endif /* RT_USING_POSIX */
+
+
+/* timezone APIs (Not standard LIBC APIs) */
+#ifndef RT_LIBC_DEFAULT_TIMEZONE
+#define RT_LIBC_DEFAULT_TIMEZONE    8
+#endif
+
+#include <rthw.h>
+
+volatile static rt_int8_t rt_current_timezone = RT_LIBC_DEFAULT_TIMEZONE;
+
+void rt_tz_set(rt_int8_t tz)
+{
+    register rt_base_t level;
+    level = rt_hw_interrupt_disable();
+    rt_current_timezone = tz;
+    rt_hw_interrupt_enable(level);
+}
+
+rt_int8_t rt_tz_get(void)
+{
+    return rt_current_timezone;
+}
+
+rt_int8_t rt_tz_is_dst(void)
+{
+    return 0;
+}