shared/timeutils: Standardize supported date range on all platforms.

yoctopuce · dpgeorge · commit df05caea6c64 · 2025-07-09T11:54:21.000+10:00
This is code makes sure that time functions work properly on a
reasonable date range, on all platforms, regardless of the epoch.
The suggested minimum range is 1970 to 2099.

In order to reduce code footprint, code to support far away dates
is only enabled specified by the port.

New types are defined to identify timestamps.

The implementation with the smallest code footprint is when
support timerange is limited to 1970-2099 and Epoch is 1970.
This makes it possible to use 32 bit unsigned integers for
all timestamps.

On ARM4F, adding support for dates up to year 3000 adds
460 bytes of code. Supporting dates back to 1600 adds
another 44 bytes of code.

Signed-off-by: Yoctopuce dev &lt;dev@yoctopuce.com&gt;
diff --git a/extmod/modtime.c b/extmod/modtime.c
@@ -58,7 +58,7 @@ static mp_obj_t time_localtime(size_t n_args, const mp_obj_t *args) {
         return mp_time_localtime_get();
     } else {
         // Convert given seconds to tuple.
-        mp_int_t seconds = mp_obj_get_int(args[0]);
+        mp_timestamp_t seconds = timeutils_obj_get_timestamp(args[0]);
         timeutils_struct_time_t tm;
         timeutils_seconds_since_epoch_to_struct_time(seconds, &tm);
         mp_obj_t tuple[8] = {
@@ -90,7 +90,7 @@ static mp_obj_t time_mktime(mp_obj_t tuple) {
         mp_raise_TypeError(MP_ERROR_TEXT("mktime needs a tuple of length 8 or 9"));
     }
 
-    return mp_obj_new_int_from_uint(timeutils_mktime(mp_obj_get_int(elem[0]),
+    return timeutils_obj_from_timestamp(timeutils_mktime(mp_obj_get_int(elem[0]),
         mp_obj_get_int(elem[1]), mp_obj_get_int(elem[2]), mp_obj_get_int(elem[3]),
         mp_obj_get_int(elem[4]), mp_obj_get_int(elem[5])));
 }
diff --git a/extmod/vfs_fat.c b/extmod/vfs_fat.c
@@ -326,7 +326,7 @@ static mp_obj_t fat_vfs_stat(mp_obj_t vfs_in, mp_obj_t path_in) {
     } else {
         mode |= MP_S_IFREG;
     }
-    mp_int_t seconds = timeutils_seconds_since_epoch(
+    mp_timestamp_t seconds = timeutils_seconds_since_epoch(
         1980 + ((fno.fdate >> 9) & 0x7f),
         (fno.fdate >> 5) & 0x0f,
         fno.fdate & 0x1f,
@@ -341,9 +341,9 @@ static mp_obj_t fat_vfs_stat(mp_obj_t vfs_in, mp_obj_t path_in) {
     t->items[4] = MP_OBJ_NEW_SMALL_INT(0); // st_uid
     t->items[5] = MP_OBJ_NEW_SMALL_INT(0); // st_gid
     t->items[6] = mp_obj_new_int_from_uint(fno.fsize); // st_size
-    t->items[7] = mp_obj_new_int_from_uint(seconds); // st_atime
-    t->items[8] = mp_obj_new_int_from_uint(seconds); // st_mtime
-    t->items[9] = mp_obj_new_int_from_uint(seconds); // st_ctime
+    t->items[7] = timeutils_obj_from_timestamp(seconds); // st_atime
+    t->items[8] = timeutils_obj_from_timestamp(seconds); // st_mtime
+    t->items[9] = timeutils_obj_from_timestamp(seconds); // st_ctime
 
     return MP_OBJ_FROM_PTR(t);
 }
diff --git a/extmod/vfs_lfsx.c b/extmod/vfs_lfsx.c
@@ -378,7 +378,7 @@ static mp_obj_t MP_VFS_LFSx(stat)(mp_obj_t self_in, mp_obj_t path_in) {
         mp_raise_OSError(-ret);
     }
 
-    mp_uint_t mtime = 0;
+    mp_timestamp_t mtime = 0;
     #if LFS_BUILD_VERSION == 2
     uint8_t mtime_buf[8];
     lfs2_ssize_t sz = lfs2_getattr(&self->lfs, path, LFS_ATTR_MTIME, &mtime_buf, sizeof(mtime_buf));
@@ -400,9 +400,9 @@ static mp_obj_t MP_VFS_LFSx(stat)(mp_obj_t self_in, mp_obj_t path_in) {
     t->items[4] = MP_OBJ_NEW_SMALL_INT(0); // st_uid
     t->items[5] = MP_OBJ_NEW_SMALL_INT(0); // st_gid
     t->items[6] = mp_obj_new_int_from_uint(info.size); // st_size
-    t->items[7] = mp_obj_new_int_from_uint(mtime); // st_atime
-    t->items[8] = mp_obj_new_int_from_uint(mtime); // st_mtime
-    t->items[9] = mp_obj_new_int_from_uint(mtime); // st_ctime
+    t->items[7] = timeutils_obj_from_timestamp(mtime); // st_atime
+    t->items[8] = timeutils_obj_from_timestamp(mtime); // st_mtime
+    t->items[9] = timeutils_obj_from_timestamp(mtime); // st_ctime
 
     return MP_OBJ_FROM_PTR(t);
 }
diff --git a/ports/cc3200/mods/modtime.c b/ports/cc3200/mods/modtime.c
@@ -50,5 +50,5 @@ static mp_obj_t mp_time_localtime_get(void) {
 
 // Returns the number of seconds, as an integer, since the Epoch.
 static mp_obj_t mp_time_time_get(void) {
-    return mp_obj_new_int(pyb_rtc_get_seconds());
+    return timeutils_obj_from_timestamp(pyb_rtc_get_seconds());
 }
diff --git a/ports/esp32/modtime.c b/ports/esp32/modtime.c
@@ -54,5 +54,5 @@ static mp_obj_t mp_time_localtime_get(void) {
 static mp_obj_t mp_time_time_get(void) {
     struct timeval tv;
     gettimeofday(&tv, NULL);
-    return mp_obj_new_int(tv.tv_sec);
+    return timeutils_obj_from_timestamp(tv.tv_sec);
 }
diff --git a/ports/esp8266/modtime.c b/ports/esp8266/modtime.c
@@ -31,7 +31,7 @@
 
 // Return the localtime as an 8-tuple.
 static mp_obj_t mp_time_localtime_get(void) {
-    mp_int_t seconds = pyb_rtc_get_us_since_epoch() / 1000 / 1000;
+    mp_uint_t seconds = pyb_rtc_get_us_since_epoch() / 1000u / 1000u;
     timeutils_struct_time_t tm;
     timeutils_seconds_since_epoch_to_struct_time(seconds, &tm);
     mp_obj_t tuple[8] = {
@@ -50,5 +50,5 @@ static mp_obj_t mp_time_localtime_get(void) {
 // Returns the number of seconds, as an integer, since the Epoch.
 static mp_obj_t mp_time_time_get(void) {
     // get date and time
-    return mp_obj_new_int(pyb_rtc_get_us_since_epoch() / 1000 / 1000);
+    return timeutils_obj_from_timestamp(pyb_rtc_get_us_since_epoch() / 1000 / 1000);
 }
diff --git a/ports/mimxrt/modtime.c b/ports/mimxrt/modtime.c
@@ -51,14 +51,7 @@ static mp_obj_t mp_time_localtime_get(void) {
 static mp_obj_t mp_time_time_get(void) {
     snvs_lp_srtc_datetime_t t;
     SNVS_LP_SRTC_GetDatetime(SNVS, &t);
-    // EPOCH is 1970 for this port, which leads to the following trouble:
-    // timeutils_seconds_since_epoch() calls timeutils_seconds_since_2000(), and
-    // timeutils_seconds_since_2000() subtracts 2000 from year, but uses
-    // an unsigned number for seconds, That causes an underrun, which is not
-    // fixed by adding the TIMEUTILS_SECONDS_1970_TO_2000.
-    // Masking it to 32 bit for year < 2000 fixes it.
-    return mp_obj_new_int_from_ull(
+    return timeutils_obj_from_timestamp(
         timeutils_seconds_since_epoch(t.year, t.month, t.day, t.hour, t.minute, t.second)
-        & (t.year < 2000 ? 0xffffffff : 0xffffffffffff)
         );
 }
diff --git a/ports/renesas-ra/modtime.c b/ports/renesas-ra/modtime.c
@@ -53,5 +53,5 @@ static mp_obj_t mp_time_time_get(void) {
     rtc_init_finalise();
     ra_rtc_t time;
     ra_rtc_get_time(&time);
-    return mp_obj_new_int(timeutils_seconds_since_epoch(time.year, time.month, time.date, time.hour, time.minute, time.second));
+    return timeutils_obj_from_timestamp(timeutils_seconds_since_epoch(time.year, time.month, time.date, time.hour, time.minute, time.second));
 }
diff --git a/ports/stm32/modtime.c b/ports/stm32/modtime.c
@@ -59,5 +59,5 @@ static mp_obj_t mp_time_time_get(void) {
     RTC_TimeTypeDef time;
     HAL_RTC_GetTime(&RTCHandle, &time, RTC_FORMAT_BIN);
     HAL_RTC_GetDate(&RTCHandle, &date, RTC_FORMAT_BIN);
-    return mp_obj_new_int(timeutils_seconds_since_epoch(2000 + date.Year, date.Month, date.Date, time.Hours, time.Minutes, time.Seconds));
+    return timeutils_obj_from_timestamp(timeutils_seconds_since_epoch(2000 + date.Year, date.Month, date.Date, time.Hours, time.Minutes, time.Seconds));
 }
diff --git a/ports/stm32/mpconfigport.h b/ports/stm32/mpconfigport.h
@@ -76,6 +76,7 @@
 #ifndef MICROPY_FLOAT_IMPL // can be configured by each board via mpconfigboard.mk
 #define MICROPY_FLOAT_IMPL          (MICROPY_FLOAT_IMPL_FLOAT)
 #endif
+#define MICROPY_TIME_SUPPORT_Y1969_AND_BEFORE (1)
 #define MICROPY_USE_INTERNAL_ERRNO  (1)
 #define MICROPY_SCHEDULER_STATIC_NODES (1)
 #define MICROPY_SCHEDULER_DEPTH     (8)
diff --git a/ports/unix/Makefile b/ports/unix/Makefile
@@ -52,6 +52,10 @@ CFLAGS += $(INC) $(CWARN) -std=gnu99 -DUNIX $(COPT) -I$(VARIANT_DIR) $(CFLAGS_EX
 # This option has no effect on 64-bit builds.
 CFLAGS += -D_FILE_OFFSET_BITS=64
 
+# Force the use of 64-bits for time_t in C library functions on 32-bit platforms.
+# This option has no effect on 64-bit builds.
+CFLAGS += -D_TIME_BITS=64
+
 # Debugging/Optimization
 ifdef DEBUG
 COPT ?= -Og
diff --git a/ports/unix/modtime.c b/ports/unix/modtime.c
@@ -34,6 +34,7 @@
 
 #include "py/mphal.h"
 #include "py/runtime.h"
+#include "shared/timeutils/timeutils.h"
 
 #ifdef _WIN32
 static inline int msec_sleep_tv(struct timeval *tv) {
@@ -130,12 +131,7 @@ static mp_obj_t mod_time_gm_local_time(size_t n_args, const mp_obj_t *args, stru
     if (n_args == 0) {
         t = time(NULL);
     } else {
-        #if MICROPY_PY_BUILTINS_FLOAT && MICROPY_FLOAT_IMPL == MICROPY_FLOAT_IMPL_DOUBLE
-        mp_float_t val = mp_obj_get_float(args[0]);
-        t = (time_t)MICROPY_FLOAT_C_FUN(trunc)(val);
-        #else
-        t = mp_obj_get_int(args[0]);
-        #endif
+        t = (time_t)timeutils_obj_get_timestamp(args[0]);
     }
     struct tm *tm = time_func(&t);
 
@@ -196,7 +192,7 @@ static mp_obj_t mod_time_mktime(mp_obj_t tuple) {
     if (ret == -1) {
         mp_raise_msg(&mp_type_OverflowError, MP_ERROR_TEXT("invalid mktime usage"));
     }
-    return mp_obj_new_int(ret);
+    return timeutils_obj_from_timestamp(ret);
 }
 MP_DEFINE_CONST_FUN_OBJ_1(mod_time_mktime_obj, mod_time_mktime);
 
diff --git a/ports/unix/mpconfigport.h b/ports/unix/mpconfigport.h
@@ -124,6 +124,9 @@ typedef long mp_off_t;
 // VFS stat functions should return time values relative to 1970/1/1
 #define MICROPY_EPOCH_IS_1970       (1)
 
+// port modtime functions use time_t
+#define MICROPY_TIMESTAMP_IMPL      (MICROPY_TIMESTAMP_IMPL_TIME_T)
+
 // Assume that select() call, interrupted with a signal, and erroring
 // with EINTR, updates remaining timeout value.
 #define MICROPY_SELECT_REMAINING_TIME (1)
diff --git a/ports/windows/Makefile b/ports/windows/Makefile
@@ -46,6 +46,10 @@ LDFLAGS += -lm -lbcrypt $(LDFLAGS_EXTRA)
 # This option has no effect on 64-bit builds.
 CFLAGS += -D_FILE_OFFSET_BITS=64
 
+# Force the use of 64-bits for time_t in C library functions on 32-bit platforms.
+# This option has no effect on 64-bit builds.
+CFLAGS += -D_TIME_BITS=64
+
 # Debugging/Optimization
 ifdef DEBUG
 CFLAGS += -g
diff --git a/py/mpconfig.h b/py/mpconfig.h
@@ -893,6 +893,64 @@ typedef double mp_float_t;
 #define MICROPY_FULL_CHECKS (MICROPY_CONFIG_ROM_LEVEL_AT_LEAST_CORE_FEATURES)
 #endif
 
+// Ports can choose to use timestamps based on 2000-01-01 or 1970-01-01
+// Default is timestamps based on 2000-01-01
+#if !defined(MICROPY_EPOCH_IS_2000) && !defined(MICROPY_EPOCH_IS_1970)
+#define MICROPY_EPOCH_IS_2000 (1)
+#define MICROPY_EPOCH_IS_1970 (0)
+#elif !defined(MICROPY_EPOCH_IS_1970)
+#define MICROPY_EPOCH_IS_1970 (1 - (MICROPY_EPOCH_IS_2000))
+#elif !defined(MICROPY_EPOCH_IS_2000)
+#define MICROPY_EPOCH_IS_2000 (1 - (MICROPY_EPOCH_IS_1970))
+#endif
+
+// To maintain reasonable compatibility with CPython on embedded systems,
+// and avoid breaking anytime soon, time functions are defined to work
+// at least between 1970 and 2099 (included) on any machine.
+//
+// Specific ports can enable extended date support
+// - after 2099 using MICROPY_TIME_SUPPORT_Y2100_AND_BEYOND
+// - before 1970 using MICROPY_TIME_SUPPORT_Y1969_AND_BEFORE
+// The largest possible range is year 1600 to year 3000
+//
+// By default, extended date support is only enabled for machines using 64 bit pointers,
+// but it can be enabled by specific ports
+#ifndef MICROPY_TIME_SUPPORT_Y1969_AND_BEFORE
+#if MP_SSIZE_MAX > 2147483647
+#define MICROPY_TIME_SUPPORT_Y1969_AND_BEFORE (1)
+#else
+#define MICROPY_TIME_SUPPORT_Y1969_AND_BEFORE (0)
+#endif
+#endif
+
+// When support for dates <1970 is enabled, supporting >=2100 does not cost anything
+#ifndef MICROPY_TIME_SUPPORT_Y2100_AND_BEYOND
+#define MICROPY_TIME_SUPPORT_Y2100_AND_BEYOND (MICROPY_TIME_SUPPORT_Y1969_AND_BEFORE)
+#endif
+
+// The type to be used to represent platform-specific timestamps depends on the choices above
+#define MICROPY_TIMESTAMP_IMPL_LONG_LONG (0)
+#define MICROPY_TIMESTAMP_IMPL_UINT (1)
+#define MICROPY_TIMESTAMP_IMPL_TIME_T (2)
+
+#ifndef MICROPY_TIMESTAMP_IMPL
+#if MICROPY_TIME_SUPPORT_Y2100_AND_BEYOND || MICROPY_TIME_SUPPORT_Y1969_AND_BEFORE || MICROPY_EPOCH_IS_2000
+#define MICROPY_TIMESTAMP_IMPL (MICROPY_TIMESTAMP_IMPL_LONG_LONG)
+#else
+#define MICROPY_TIMESTAMP_IMPL (MICROPY_TIMESTAMP_IMPL_UINT)
+#endif
+#endif
+
+// `mp_timestamp_t` is the type that should be used by the port
+// to represent timestamps, and is referenced to the platform epoch
+#if MICROPY_TIMESTAMP_IMPL == MICROPY_TIMESTAMP_IMPL_LONG_LONG
+typedef long long mp_timestamp_t;
+#elif MICROPY_TIMESTAMP_IMPL == MICROPY_TIMESTAMP_IMPL_UINT
+typedef mp_uint_t mp_timestamp_t;
+#elif MICROPY_TIMESTAMP_IMPL == MICROPY_TIMESTAMP_IMPL_TIME_T
+typedef time_t mp_timestamp_t;
+#endif
+
 // Whether POSIX-semantics non-blocking streams are supported
 #ifndef MICROPY_STREAMS_NON_BLOCK
 #define MICROPY_STREAMS_NON_BLOCK (MICROPY_CONFIG_ROM_LEVEL_AT_LEAST_EXTRA_FEATURES)
diff --git a/shared/timeutils/timeutils.c b/shared/timeutils/timeutils.c
diff --git a/shared/timeutils/timeutils.h b/shared/timeutils/timeutils.h
diff --git a/tests/extmod/time_mktime.py b/tests/extmod/time_mktime.py

Original file line number	Diff line number	Diff line change
`@@ -50,5 +50,5 @@ static mp_obj_t mp_time_localtime_get(void) {`
`50`	`50`
`51`	`51`	`// Returns the number of seconds, as an integer, since the Epoch.`
`52`	`52`	`static mp_obj_t mp_time_time_get(void) {`
`53`		`- return mp_obj_new_int(pyb_rtc_get_seconds());`
	`53`	`+ return timeutils_obj_from_timestamp(pyb_rtc_get_seconds());`
`54`	`54`	`}`
Original file line number	Diff line number	Diff line change
`@@ -54,5 +54,5 @@ static mp_obj_t mp_time_localtime_get(void) {`
`54`	`54`	`static mp_obj_t mp_time_time_get(void) {`
`55`	`55`	`struct timeval tv;`
`56`	`56`	`gettimeofday(&tv, NULL);`
`57`		`- return mp_obj_new_int(tv.tv_sec);`
	`57`	`+ return timeutils_obj_from_timestamp(tv.tv_sec);`
`58`	`58`	`}`
Original file line number	Diff line number	Diff line change
`@@ -53,5 +53,5 @@ static mp_obj_t mp_time_time_get(void) {`
`53`	`53`	`rtc_init_finalise();`
`54`	`54`	`ra_rtc_t time;`
`55`	`55`	`ra_rtc_get_time(&time);`
`56`		`- return mp_obj_new_int(timeutils_seconds_since_epoch(time.year, time.month, time.date, time.hour, time.minute, time.second));`
	`56`	`+ return timeutils_obj_from_timestamp(timeutils_seconds_since_epoch(time.year, time.month, time.date, time.hour, time.minute, time.second));`
`57`	`57`	`}`
Original file line number	Diff line number	Diff line change
`@@ -59,5 +59,5 @@ static mp_obj_t mp_time_time_get(void) {`
`59`	`59`	`RTC_TimeTypeDef time;`
`60`	`60`	`HAL_RTC_GetTime(&RTCHandle, &time, RTC_FORMAT_BIN);`
`61`	`61`	`HAL_RTC_GetDate(&RTCHandle, &date, RTC_FORMAT_BIN);`
`62`		`- return mp_obj_new_int(timeutils_seconds_since_epoch(2000 + date.Year, date.Month, date.Date, time.Hours, time.Minutes, time.Seconds));`
	`62`	`+ return timeutils_obj_from_timestamp(timeutils_seconds_since_epoch(2000 + date.Year, date.Month, date.Date, time.Hours, time.Minutes, time.Seconds));`
`63`	`63`	`}`