| /* |
| |
| 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. |
| |
| */ |
| |
| /* |
| |
| 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. |
| |
| S_localtime64_r() is a 64-bit equivalent of localtime_r(). |
| |
| S_gmtime64_r() is a 64-bit equivalent of gmtime_r(). |
| |
| */ |
| |
| #include "time64.h" |
| |
| 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 const int length_of_year[2] = { 365, 366 }; |
| |
| /* Number of days in a 400 year Gregorian cycle */ |
| static const Year years_in_gregorian_cycle = 400; |
| static const int days_in_gregorian_cycle = (365 * 400) + 100 - 4 + 1; |
| |
| /* 28 year calendar cycle between 2010 and 2037 */ |
| #define SOLAR_CYCLE_LENGTH 28 |
| static const int safe_years[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 |
| }; |
| |
| 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 */ |
| 6, 1, 2, 3, /* 12 */ |
| 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 TIME64_TRACE(format) (fprintf(stderr, format)) |
| # define TIME64_TRACE1(format, var1) (fprintf(stderr, format, var1)) |
| # define TIME64_TRACE2(format, var1, var2) (fprintf(stderr, format, var1, var2)) |
| # define TIME64_TRACE3(format, var1, var2, var3) (fprintf(stderr, format, var1, var2, var3)) |
| #else |
| # define TIME64_TRACE(format) ((void)0) |
| # define TIME64_TRACE1(format, var1) ((void)0) |
| # define TIME64_TRACE2(format, var1, var2) ((void)0) |
| # define TIME64_TRACE3(format, var1, var2, var3) ((void)0) |
| #endif |
| |
| static int S_is_exception_century(Year year) |
| { |
| int is_exception = ((year % 100 == 0) && !(year % 400 == 0)); |
| TIME64_TRACE1("# is_exception_century: %s\n", is_exception ? "yes" : "no"); |
| |
| return(is_exception); |
| } |
| |
| |
| static Time64_T S_timegm64(struct TM *date) { |
| int days = 0; |
| Time64_T seconds = 0; |
| Year year; |
| |
| if( date->tm_year > 70 ) { |
| year = 70; |
| while( year < date->tm_year ) { |
| days += length_of_year[IS_LEAP(year)]; |
| year++; |
| } |
| } |
| else if ( date->tm_year < 70 ) { |
| year = 69; |
| do { |
| days -= length_of_year[IS_LEAP(year)]; |
| year--; |
| } while( year >= date->tm_year ); |
| } |
| |
| days += julian_days_by_month[IS_LEAP(date->tm_year)][date->tm_mon]; |
| days += date->tm_mday - 1; |
| |
| /* Avoid overflowing the days integer */ |
| seconds = days; |
| seconds = seconds * 60 * 60 * 24; |
| |
| seconds += date->tm_hour * 60 * 60; |
| seconds += date->tm_min * 60; |
| seconds += date->tm_sec; |
| |
| return(seconds); |
| } |
| |
| |
| #ifdef DEBUGGING |
| static int S_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; |
| } |
| #endif |
| |
| |
| /* The exceptional centuries without leap years cause the cycle to |
| shift by 16 |
| */ |
| static Year S_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; |
| |
| TIME64_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 S_safe_year(Year year) |
| { |
| int safe_year; |
| Year year_cycle = year + S_cycle_offset(year); |
| |
| /* Change non-leap xx00 years to an equivalent */ |
| if( S_is_exception_century(year) ) |
| year_cycle += 11; |
| |
| /* Also xx01 years, since the previous year will be wrong */ |
| if( S_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 ); |
| safe_year = safe_years[year_cycle]; |
| |
| assert(safe_year <= 2037 && safe_year >= 2010); |
| |
| TIME64_TRACE3("# year: %lld, year_cycle: %lld, safe_year: %d\n", |
| year, year_cycle, safe_year); |
| |
| return safe_year; |
| } |
| |
| |
| static void S_copy_little_tm_to_big_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 |
| } |
| } |
| |
| |
| #ifndef HAS_LOCALTIME_R |
| /* Simulate localtime_r() to the best of our ability */ |
| static struct tm * S_localtime_r(const time_t *clock, struct tm *result) { |
| dTHX; /* in case the following is defined as Perl_my_localtime(aTHX_ ...) */ |
| 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; |
| } |
| } |
| #endif |
| |
| #ifndef HAS_GMTIME_R |
| /* Simulate gmtime_r() to the best of our ability */ |
| static struct tm * S_gmtime_r(const time_t *clock, struct tm *result) { |
| dTHX; /* in case the following is defined as Perl_my_gmtime(aTHX_ ...) */ |
| 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; |
| } |
| } |
| #endif |
| |
| static struct TM *S_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 = (time_t)*in_time; |
| struct tm safe_date; |
| GMTIME_R(&safe_time, &safe_date); |
| |
| S_copy_little_tm_to_big_TM(&safe_date, p); |
| assert(S_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 = (char *)"UTC"; |
| #endif |
| |
| v_tm_sec = (int)fmod(time, 60.0); |
| time = time >= 0 ? floor(time / 60.0) : ceil(time / 60.0); |
| v_tm_min = (int)fmod(time, 60.0); |
| time = time >= 0 ? floor(time / 60.0) : ceil(time / 60.0); |
| v_tm_hour = (int)fmod(time, 24.0); |
| time = time >= 0 ? floor(time / 24.0) : ceil(time / 24.0); |
| 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)fmod((v_tm_tday + 4.0), 7.0); |
| 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)floor(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)ceil((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(S_check_tm(p)); |
| |
| return p; |
| } |
| |
| |
| static struct TM *S_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_t)*time; |
| |
| TIME64_TRACE1("Using system localtime for %lld\n", *time); |
| |
| LOCALTIME_R(&safe_time, &safe_date); |
| |
| S_copy_little_tm_to_big_TM(&safe_date, local_tm); |
| assert(S_check_tm(local_tm)); |
| |
| return local_tm; |
| } |
| |
| if( S_gmtime64_r(time, &gm_tm) == NULL ) { |
| TIME64_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) |
| ) |
| { |
| TIME64_TRACE1("Mapping tm_year %lld to safe_year\n", (Year)gm_tm.tm_year); |
| gm_tm.tm_year = S_safe_year((Year)(gm_tm.tm_year + 1900)) - 1900; |
| } |
| |
| safe_time = (time_t)S_timegm64(&gm_tm); |
| if( LOCALTIME_R(&safe_time, &safe_date) == NULL ) { |
| TIME64_TRACE1("localtime_r(%d) returned NULL\n", (int)safe_time); |
| return NULL; |
| } |
| |
| S_copy_little_tm_to_big_TM(&safe_date, local_tm); |
| |
| local_tm->tm_year = orig_year; |
| if( local_tm->tm_year != orig_year ) { |
| TIME64_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 coming 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(S_check_tm(local_tm)); |
| |
| return local_tm; |
| } |