summaryrefslogtreecommitdiffstats
path: root/libc/bionic/time64.c
diff options
context:
space:
mode:
Diffstat (limited to 'libc/bionic/time64.c')
-rw-r--r--libc/bionic/time64.c793
1 files changed, 793 insertions, 0 deletions
diff --git a/libc/bionic/time64.c b/libc/bionic/time64.c
new file mode 100644
index 0000000..1e1f881
--- /dev/null
+++ b/libc/bionic/time64.c
@@ -0,0 +1,793 @@
+/*
+
+Copyright (c) 2007-2008 Michael G Schwern
+
+This software originally derived from Paul Sheer's pivotal_gmtime_r.c.
+
+The MIT License:
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in
+all copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+THE SOFTWARE.
+
+*/
+
+/* See http://code.google.com/p/y2038 for this code's origin */
+
+/*
+
+Programmers who have available to them 64-bit time values as a 'long
+long' type can use localtime64_r() and gmtime64_r() which correctly
+converts the time even on 32-bit systems. Whether you have 64-bit time
+values will depend on the operating system.
+
+localtime64_r() is a 64-bit equivalent of localtime_r().
+
+gmtime64_r() is a 64-bit equivalent of gmtime_r().
+
+*/
+
+#include <assert.h>
+#include <stdlib.h>
+#include <stdio.h>
+#include <string.h>
+#include <time.h>
+#include <errno.h>
+#include "time64.h"
+
+/* BIONIC_BEGIN */
+/* the following are here to avoid exposing time64_config.h and
+ * other types in our public time64.h header
+ */
+#include "time64_config.h"
+
+/* Not everyone has gm/localtime_r(), provide a replacement */
+#ifdef HAS_LOCALTIME_R
+# define LOCALTIME_R(clock, result) localtime_r(clock, result)
+#else
+# define LOCALTIME_R(clock, result) fake_localtime_r(clock, result)
+#endif
+#ifdef HAS_GMTIME_R
+# define GMTIME_R(clock, result) gmtime_r(clock, result)
+#else
+# define GMTIME_R(clock, result) fake_gmtime_r(clock, result)
+#endif
+
+typedef int64_t Int64;
+typedef time64_t Time64_T;
+typedef int64_t Year;
+#define TM tm
+/* BIONIC_END */
+
+/* Spec says except for stftime() and the _r() functions, these
+ all return static memory. Stabbings! */
+static struct TM Static_Return_Date;
+static char Static_Return_String[35];
+
+static const int days_in_month[2][12] = {
+ {31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31},
+ {31, 29, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31},
+};
+
+static const int julian_days_by_month[2][12] = {
+ {0, 31, 59, 90, 120, 151, 181, 212, 243, 273, 304, 334},
+ {0, 31, 60, 91, 121, 152, 182, 213, 244, 274, 305, 335},
+};
+
+static char const wday_name[7][3] = {
+ "Sun", "Mon", "Tue", "Wed", "Thu", "Fri", "Sat"
+};
+
+static char const mon_name[12][3] = {
+ "Jan", "Feb", "Mar", "Apr", "May", "Jun",
+ "Jul", "Aug", "Sep", "Oct", "Nov", "Dec"
+};
+
+static const int length_of_year[2] = { 365, 366 };
+
+/* Some numbers relating to the gregorian cycle */
+static const Year years_in_gregorian_cycle = 400;
+#define days_in_gregorian_cycle ((365 * 400) + 100 - 4 + 1)
+static const Time64_T seconds_in_gregorian_cycle = days_in_gregorian_cycle * 60LL * 60LL * 24LL;
+
+/* Year range we can trust the time funcitons with */
+#define MAX_SAFE_YEAR 2037
+#define MIN_SAFE_YEAR 1971
+
+/* 28 year Julian calendar cycle */
+#define SOLAR_CYCLE_LENGTH 28
+
+/* Year cycle from MAX_SAFE_YEAR down. */
+static const int safe_years_high[SOLAR_CYCLE_LENGTH] = {
+ 2016, 2017, 2018, 2019,
+ 2020, 2021, 2022, 2023,
+ 2024, 2025, 2026, 2027,
+ 2028, 2029, 2030, 2031,
+ 2032, 2033, 2034, 2035,
+ 2036, 2037, 2010, 2011,
+ 2012, 2013, 2014, 2015
+};
+
+/* Year cycle from MIN_SAFE_YEAR up */
+static const int safe_years_low[SOLAR_CYCLE_LENGTH] = {
+ 1996, 1997, 1998, 1971,
+ 1972, 1973, 1974, 1975,
+ 1976, 1977, 1978, 1979,
+ 1980, 1981, 1982, 1983,
+ 1984, 1985, 1986, 1987,
+ 1988, 1989, 1990, 1991,
+ 1992, 1993, 1994, 1995,
+};
+
+/* This isn't used, but it's handy to look at */
+static const int dow_year_start[SOLAR_CYCLE_LENGTH] = {
+ 5, 0, 1, 2, /* 0 2016 - 2019 */
+ 3, 5, 6, 0, /* 4 */
+ 1, 3, 4, 5, /* 8 1996 - 1998, 1971*/
+ 6, 1, 2, 3, /* 12 1972 - 1975 */
+ 4, 6, 0, 1, /* 16 */
+ 2, 4, 5, 6, /* 20 2036, 2037, 2010, 2011 */
+ 0, 2, 3, 4 /* 24 2012, 2013, 2014, 2015 */
+};
+
+/* Let's assume people are going to be looking for dates in the future.
+ Let's provide some cheats so you can skip ahead.
+ This has a 4x speed boost when near 2008.
+*/
+/* Number of days since epoch on Jan 1st, 2008 GMT */
+#define CHEAT_DAYS (1199145600 / 24 / 60 / 60)
+#define CHEAT_YEARS 108
+
+#define IS_LEAP(n) ((!(((n) + 1900) % 400) || (!(((n) + 1900) % 4) && (((n) + 1900) % 100))) != 0)
+#define WRAP(a,b,m) ((a) = ((a) < 0 ) ? ((b)--, (a) + (m)) : (a))
+
+#ifdef USE_SYSTEM_LOCALTIME
+# define SHOULD_USE_SYSTEM_LOCALTIME(a) ( \
+ (a) <= SYSTEM_LOCALTIME_MAX && \
+ (a) >= SYSTEM_LOCALTIME_MIN \
+)
+#else
+# define SHOULD_USE_SYSTEM_LOCALTIME(a) (0)
+#endif
+
+#ifdef USE_SYSTEM_GMTIME
+# define SHOULD_USE_SYSTEM_GMTIME(a) ( \
+ (a) <= SYSTEM_GMTIME_MAX && \
+ (a) >= SYSTEM_GMTIME_MIN \
+)
+#else
+# define SHOULD_USE_SYSTEM_GMTIME(a) (0)
+#endif
+
+/* Multi varadic macros are a C99 thing, alas */
+#ifdef TIME_64_DEBUG
+# define TRACE(format) (fprintf(stderr, format))
+# define TRACE1(format, var1) (fprintf(stderr, format, var1))
+# define TRACE2(format, var1, var2) (fprintf(stderr, format, var1, var2))
+# define TRACE3(format, var1, var2, var3) (fprintf(stderr, format, var1, var2, var3))
+#else
+# define TRACE(format) ((void)0)
+# define TRACE1(format, var1) ((void)0)
+# define TRACE2(format, var1, var2) ((void)0)
+# define TRACE3(format, var1, var2, var3) ((void)0)
+#endif
+
+
+static int is_exception_century(Year year)
+{
+ int is_exception = ((year % 100 == 0) && !(year % 400 == 0));
+ TRACE1("# is_exception_century: %s\n", is_exception ? "yes" : "no");
+
+ return(is_exception);
+}
+
+
+/* timegm() is not in the C or POSIX spec, but it is such a useful
+ extension I would be remiss in leaving it out. Also I need it
+ for localtime64()
+*/
+Time64_T timegm64(const struct TM *date) {
+ Time64_T days = 0;
+ Time64_T seconds = 0;
+ Year year;
+ Year orig_year = (Year)date->tm_year;
+ int cycles = 0;
+
+ if( orig_year > 100 ) {
+ cycles = (orig_year - 100) / 400;
+ orig_year -= cycles * 400;
+ days += (Time64_T)cycles * days_in_gregorian_cycle;
+ }
+ else if( orig_year < -300 ) {
+ cycles = (orig_year - 100) / 400;
+ orig_year -= cycles * 400;
+ days += (Time64_T)cycles * days_in_gregorian_cycle;
+ }
+ TRACE3("# timegm/ cycles: %d, days: %lld, orig_year: %lld\n", cycles, days, orig_year);
+
+ if( orig_year > 70 ) {
+ year = 70;
+ while( year < orig_year ) {
+ days += length_of_year[IS_LEAP(year)];
+ year++;
+ }
+ }
+ else if ( orig_year < 70 ) {
+ year = 69;
+ do {
+ days -= length_of_year[IS_LEAP(year)];
+ year--;
+ } while( year >= orig_year );
+ }
+
+
+ days += julian_days_by_month[IS_LEAP(orig_year)][date->tm_mon];
+ days += date->tm_mday - 1;
+
+ seconds = days * 60 * 60 * 24;
+
+ seconds += date->tm_hour * 60 * 60;
+ seconds += date->tm_min * 60;
+ seconds += date->tm_sec;
+
+ return(seconds);
+}
+
+
+static int check_tm(struct TM *tm)
+{
+ /* Don't forget leap seconds */
+ assert(tm->tm_sec >= 0);
+ assert(tm->tm_sec <= 61);
+
+ assert(tm->tm_min >= 0);
+ assert(tm->tm_min <= 59);
+
+ assert(tm->tm_hour >= 0);
+ assert(tm->tm_hour <= 23);
+
+ assert(tm->tm_mday >= 1);
+ assert(tm->tm_mday <= days_in_month[IS_LEAP(tm->tm_year)][tm->tm_mon]);
+
+ assert(tm->tm_mon >= 0);
+ assert(tm->tm_mon <= 11);
+
+ assert(tm->tm_wday >= 0);
+ assert(tm->tm_wday <= 6);
+
+ assert(tm->tm_yday >= 0);
+ assert(tm->tm_yday <= length_of_year[IS_LEAP(tm->tm_year)]);
+
+#ifdef HAS_TM_TM_GMTOFF
+ assert(tm->tm_gmtoff >= -24 * 60 * 60);
+ assert(tm->tm_gmtoff <= 24 * 60 * 60);
+#endif
+
+ return 1;
+}
+
+
+/* The exceptional centuries without leap years cause the cycle to
+ shift by 16
+*/
+static Year cycle_offset(Year year)
+{
+ const Year start_year = 2000;
+ Year year_diff = year - start_year;
+ Year exceptions;
+
+ if( year > start_year )
+ year_diff--;
+
+ exceptions = year_diff / 100;
+ exceptions -= year_diff / 400;
+
+ TRACE3("# year: %lld, exceptions: %lld, year_diff: %lld\n",
+ year, exceptions, year_diff);
+
+ return exceptions * 16;
+}
+
+/* For a given year after 2038, pick the latest possible matching
+ year in the 28 year calendar cycle.
+
+ A matching year...
+ 1) Starts on the same day of the week.
+ 2) Has the same leap year status.
+
+ This is so the calendars match up.
+
+ Also the previous year must match. When doing Jan 1st you might
+ wind up on Dec 31st the previous year when doing a -UTC time zone.
+
+ Finally, the next year must have the same start day of week. This
+ is for Dec 31st with a +UTC time zone.
+ It doesn't need the same leap year status since we only care about
+ January 1st.
+*/
+static int safe_year(const Year year)
+{
+ int safe_year = 0;
+ Year year_cycle;
+
+ if( year >= MIN_SAFE_YEAR && year <= MAX_SAFE_YEAR ) {
+ return (int)year;
+ }
+
+ year_cycle = year + cycle_offset(year);
+
+ /* safe_years_low is off from safe_years_high by 8 years */
+ if( year < MIN_SAFE_YEAR )
+ year_cycle -= 8;
+
+ /* Change non-leap xx00 years to an equivalent */
+ if( is_exception_century(year) )
+ year_cycle += 11;
+
+ /* Also xx01 years, since the previous year will be wrong */
+ if( is_exception_century(year - 1) )
+ year_cycle += 17;
+
+ year_cycle %= SOLAR_CYCLE_LENGTH;
+ if( year_cycle < 0 )
+ year_cycle = SOLAR_CYCLE_LENGTH + year_cycle;
+
+ assert( year_cycle >= 0 );
+ assert( year_cycle < SOLAR_CYCLE_LENGTH );
+ if( year < MIN_SAFE_YEAR )
+ safe_year = safe_years_low[year_cycle];
+ else if( year > MAX_SAFE_YEAR )
+ safe_year = safe_years_high[year_cycle];
+ else
+ assert(0);
+
+ TRACE3("# year: %lld, year_cycle: %lld, safe_year: %d\n",
+ year, year_cycle, safe_year);
+
+ assert(safe_year <= MAX_SAFE_YEAR && safe_year >= MIN_SAFE_YEAR);
+
+ return safe_year;
+}
+
+
+void copy_tm_to_TM(const struct tm *src, struct TM *dest) {
+ if( src == NULL ) {
+ memset(dest, 0, sizeof(*dest));
+ }
+ else {
+# ifdef USE_TM64
+ dest->tm_sec = src->tm_sec;
+ dest->tm_min = src->tm_min;
+ dest->tm_hour = src->tm_hour;
+ dest->tm_mday = src->tm_mday;
+ dest->tm_mon = src->tm_mon;
+ dest->tm_year = (Year)src->tm_year;
+ dest->tm_wday = src->tm_wday;
+ dest->tm_yday = src->tm_yday;
+ dest->tm_isdst = src->tm_isdst;
+
+# ifdef HAS_TM_TM_GMTOFF
+ dest->tm_gmtoff = src->tm_gmtoff;
+# endif
+
+# ifdef HAS_TM_TM_ZONE
+ dest->tm_zone = src->tm_zone;
+# endif
+
+# else
+ /* They're the same type */
+ memcpy(dest, src, sizeof(*dest));
+# endif
+ }
+}
+
+
+void copy_TM_to_tm(const struct TM *src, struct tm *dest) {
+ if( src == NULL ) {
+ memset(dest, 0, sizeof(*dest));
+ }
+ else {
+# ifdef USE_TM64
+ dest->tm_sec = src->tm_sec;
+ dest->tm_min = src->tm_min;
+ dest->tm_hour = src->tm_hour;
+ dest->tm_mday = src->tm_mday;
+ dest->tm_mon = src->tm_mon;
+ dest->tm_year = (int)src->tm_year;
+ dest->tm_wday = src->tm_wday;
+ dest->tm_yday = src->tm_yday;
+ dest->tm_isdst = src->tm_isdst;
+
+# ifdef HAS_TM_TM_GMTOFF
+ dest->tm_gmtoff = src->tm_gmtoff;
+# endif
+
+# ifdef HAS_TM_TM_ZONE
+ dest->tm_zone = src->tm_zone;
+# endif
+
+# else
+ /* They're the same type */
+ memcpy(dest, src, sizeof(*dest));
+# endif
+ }
+}
+
+
+/* Simulate localtime_r() to the best of our ability */
+struct tm * fake_localtime_r(const time_t *clock, struct tm *result) {
+ const struct tm *static_result = localtime(clock);
+
+ assert(result != NULL);
+
+ if( static_result == NULL ) {
+ memset(result, 0, sizeof(*result));
+ return NULL;
+ }
+ else {
+ memcpy(result, static_result, sizeof(*result));
+ return result;
+ }
+}
+
+
+
+/* Simulate gmtime_r() to the best of our ability */
+struct tm * fake_gmtime_r(const time_t *clock, struct tm *result) {
+ const struct tm *static_result = gmtime(clock);
+
+ assert(result != NULL);
+
+ if( static_result == NULL ) {
+ memset(result, 0, sizeof(*result));
+ return NULL;
+ }
+ else {
+ memcpy(result, static_result, sizeof(*result));
+ return result;
+ }
+}
+
+
+static Time64_T seconds_between_years(Year left_year, Year right_year) {
+ int increment = (left_year > right_year) ? 1 : -1;
+ Time64_T seconds = 0;
+ int cycles;
+
+ if( left_year > 2400 ) {
+ cycles = (left_year - 2400) / 400;
+ left_year -= cycles * 400;
+ seconds += cycles * seconds_in_gregorian_cycle;
+ }
+ else if( left_year < 1600 ) {
+ cycles = (left_year - 1600) / 400;
+ left_year += cycles * 400;
+ seconds += cycles * seconds_in_gregorian_cycle;
+ }
+
+ while( left_year != right_year ) {
+ seconds += length_of_year[IS_LEAP(right_year - 1900)] * 60 * 60 * 24;
+ right_year += increment;
+ }
+
+ return seconds * increment;
+}
+
+
+Time64_T mktime64(const struct TM *input_date) {
+ struct tm safe_date;
+ struct TM date;
+ Time64_T time;
+ Year year = input_date->tm_year + 1900;
+
+ if( MIN_SAFE_YEAR <= year && year <= MAX_SAFE_YEAR ) {
+ copy_TM_to_tm(input_date, &safe_date);
+ return (Time64_T)mktime(&safe_date);
+ }
+
+ /* Have to make the year safe in date else it won't fit in safe_date */
+ date = *input_date;
+ date.tm_year = safe_year(year) - 1900;
+ copy_TM_to_tm(&date, &safe_date);
+
+ time = (Time64_T)mktime(&safe_date);
+
+ time += seconds_between_years(year, (Year)(safe_date.tm_year + 1900));
+
+ return time;
+}
+
+
+/* Because I think mktime() is a crappy name */
+Time64_T timelocal64(const struct TM *date) {
+ return mktime64(date);
+}
+
+
+struct TM *gmtime64_r (const Time64_T *in_time, struct TM *p)
+{
+ int v_tm_sec, v_tm_min, v_tm_hour, v_tm_mon, v_tm_wday;
+ Time64_T v_tm_tday;
+ int leap;
+ Time64_T m;
+ Time64_T time = *in_time;
+ Year year = 70;
+ int cycles = 0;
+
+ assert(p != NULL);
+
+ /* Use the system gmtime() if time_t is small enough */
+ if( SHOULD_USE_SYSTEM_GMTIME(*in_time) ) {
+ time_t safe_time = *in_time;
+ struct tm safe_date;
+ GMTIME_R(&safe_time, &safe_date);
+
+ copy_tm_to_TM(&safe_date, p);
+ assert(check_tm(p));
+
+ return p;
+ }
+
+#ifdef HAS_TM_TM_GMTOFF
+ p->tm_gmtoff = 0;
+#endif
+ p->tm_isdst = 0;
+
+#ifdef HAS_TM_TM_ZONE
+ p->tm_zone = "UTC";
+#endif
+
+ v_tm_sec = (int)(time % 60);
+ time /= 60;
+ v_tm_min = (int)(time % 60);
+ time /= 60;
+ v_tm_hour = (int)(time % 24);
+ time /= 24;
+ v_tm_tday = time;
+
+ WRAP (v_tm_sec, v_tm_min, 60);
+ WRAP (v_tm_min, v_tm_hour, 60);
+ WRAP (v_tm_hour, v_tm_tday, 24);
+
+ v_tm_wday = (int)((v_tm_tday + 4) % 7);
+ if (v_tm_wday < 0)
+ v_tm_wday += 7;
+ m = v_tm_tday;
+
+ if (m >= CHEAT_DAYS) {
+ year = CHEAT_YEARS;
+ m -= CHEAT_DAYS;
+ }
+
+ if (m >= 0) {
+ /* Gregorian cycles, this is huge optimization for distant times */
+ cycles = (int)(m / (Time64_T) days_in_gregorian_cycle);
+ if( cycles ) {
+ m -= (cycles * (Time64_T) days_in_gregorian_cycle);
+ year += (cycles * years_in_gregorian_cycle);
+ }
+
+ /* Years */
+ leap = IS_LEAP (year);
+ while (m >= (Time64_T) length_of_year[leap]) {
+ m -= (Time64_T) length_of_year[leap];
+ year++;
+ leap = IS_LEAP (year);
+ }
+
+ /* Months */
+ v_tm_mon = 0;
+ while (m >= (Time64_T) days_in_month[leap][v_tm_mon]) {
+ m -= (Time64_T) days_in_month[leap][v_tm_mon];
+ v_tm_mon++;
+ }
+ } else {
+ year--;
+
+ /* Gregorian cycles */
+ cycles = (int)((m / (Time64_T) days_in_gregorian_cycle) + 1);
+ if( cycles ) {
+ m -= (cycles * (Time64_T) days_in_gregorian_cycle);
+ year += (cycles * years_in_gregorian_cycle);
+ }
+
+ /* Years */
+ leap = IS_LEAP (year);
+ while (m < (Time64_T) -length_of_year[leap]) {
+ m += (Time64_T) length_of_year[leap];
+ year--;
+ leap = IS_LEAP (year);
+ }
+
+ /* Months */
+ v_tm_mon = 11;
+ while (m < (Time64_T) -days_in_month[leap][v_tm_mon]) {
+ m += (Time64_T) days_in_month[leap][v_tm_mon];
+ v_tm_mon--;
+ }
+ m += (Time64_T) days_in_month[leap][v_tm_mon];
+ }
+
+ p->tm_year = year;
+ if( p->tm_year != year ) {
+#ifdef EOVERFLOW
+ errno = EOVERFLOW;
+#endif
+ return NULL;
+ }
+
+ /* At this point m is less than a year so casting to an int is safe */
+ p->tm_mday = (int) m + 1;
+ p->tm_yday = julian_days_by_month[leap][v_tm_mon] + (int)m;
+ p->tm_sec = v_tm_sec;
+ p->tm_min = v_tm_min;
+ p->tm_hour = v_tm_hour;
+ p->tm_mon = v_tm_mon;
+ p->tm_wday = v_tm_wday;
+
+ assert(check_tm(p));
+
+ return p;
+}
+
+
+struct TM *localtime64_r (const Time64_T *time, struct TM *local_tm)
+{
+ time_t safe_time;
+ struct tm safe_date;
+ struct TM gm_tm;
+ Year orig_year;
+ int month_diff;
+
+ assert(local_tm != NULL);
+
+ /* Use the system localtime() if time_t is small enough */
+ if( SHOULD_USE_SYSTEM_LOCALTIME(*time) ) {
+ safe_time = *time;
+
+ TRACE1("Using system localtime for %lld\n", *time);
+
+ LOCALTIME_R(&safe_time, &safe_date);
+
+ copy_tm_to_TM(&safe_date, local_tm);
+ assert(check_tm(local_tm));
+
+ return local_tm;
+ }
+
+ if( gmtime64_r(time, &gm_tm) == NULL ) {
+ TRACE1("gmtime64_r returned null for %lld\n", *time);
+ return NULL;
+ }
+
+ orig_year = gm_tm.tm_year;
+
+ if (gm_tm.tm_year > (2037 - 1900) ||
+ gm_tm.tm_year < (1970 - 1900)
+ )
+ {
+ TRACE1("Mapping tm_year %lld to safe_year\n", (Year)gm_tm.tm_year);
+ gm_tm.tm_year = safe_year((Year)(gm_tm.tm_year + 1900)) - 1900;
+ }
+
+ safe_time = timegm64(&gm_tm);
+ if( LOCALTIME_R(&safe_time, &safe_date) == NULL ) {
+ TRACE1("localtime_r(%d) returned NULL\n", (int)safe_time);
+ return NULL;
+ }
+
+ copy_tm_to_TM(&safe_date, local_tm);
+
+ local_tm->tm_year = orig_year;
+ if( local_tm->tm_year != orig_year ) {
+ TRACE2("tm_year overflow: tm_year %lld, orig_year %lld\n",
+ (Year)local_tm->tm_year, (Year)orig_year);
+
+#ifdef EOVERFLOW
+ errno = EOVERFLOW;
+#endif
+ return NULL;
+ }
+
+
+ month_diff = local_tm->tm_mon - gm_tm.tm_mon;
+
+ /* When localtime is Dec 31st previous year and
+ gmtime is Jan 1st next year.
+ */
+ if( month_diff == 11 ) {
+ local_tm->tm_year--;
+ }
+
+ /* When localtime is Jan 1st, next year and
+ gmtime is Dec 31st, previous year.
+ */
+ if( month_diff == -11 ) {
+ local_tm->tm_year++;
+ }
+
+ /* GMT is Jan 1st, xx01 year, but localtime is still Dec 31st
+ in a non-leap xx00. There is one point in the cycle
+ we can't account for which the safe xx00 year is a leap
+ year. So we need to correct for Dec 31st comming out as
+ the 366th day of the year.
+ */
+ if( !IS_LEAP(local_tm->tm_year) && local_tm->tm_yday == 365 )
+ local_tm->tm_yday--;
+
+ assert(check_tm(local_tm));
+
+ return local_tm;
+}
+
+
+int valid_tm_wday( const struct TM* date ) {
+ if( 0 <= date->tm_wday && date->tm_wday <= 6 )
+ return 1;
+ else
+ return 0;
+}
+
+int valid_tm_mon( const struct TM* date ) {
+ if( 0 <= date->tm_mon && date->tm_mon <= 11 )
+ return 1;
+ else
+ return 0;
+}
+
+
+char *asctime64_r( const struct TM* date, char *result ) {
+ /* I figure everything else can be displayed, even hour 25, but if
+ these are out of range we walk off the name arrays */
+ if( !valid_tm_wday(date) || !valid_tm_mon(date) )
+ return NULL;
+
+ sprintf(result, "%.3s %.3s%3d %.2d:%.2d:%.2d %d\n",
+ wday_name[date->tm_wday],
+ mon_name[date->tm_mon],
+ date->tm_mday, date->tm_hour,
+ date->tm_min, date->tm_sec,
+ 1900 + date->tm_year);
+
+ return result;
+}
+
+
+char *ctime64_r( const Time64_T* time, char* result ) {
+ struct TM date;
+
+ localtime64_r( time, &date );
+ return asctime64_r( &date, result );
+}
+
+
+/* Non-thread safe versions of the above */
+struct TM *localtime64(const Time64_T *time) {
+ return localtime64_r(time, &Static_Return_Date);
+}
+
+struct TM *gmtime64(const Time64_T *time) {
+ return gmtime64_r(time, &Static_Return_Date);
+}
+
+char *asctime64( const struct TM* date ) {
+ return asctime64_r( date, Static_Return_String );
+}
+
+char *ctime64( const Time64_T* time ) {
+ return asctime64(localtime64(time));
+}