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Diffstat (limited to 'src/timefns.c')
| -rw-r--r-- | src/timefns.c | 1287 |
1 files changed, 1287 insertions, 0 deletions
diff --git a/src/timefns.c b/src/timefns.c new file mode 100644 index 00000000000..fcb4485ae30 --- /dev/null +++ b/src/timefns.c @@ -0,0 +1,1287 @@ +/* Timestamp functions for Emacs + +Copyright (C) 1985-1987, 1989, 1993-2018 Free Software Foundation, Inc. + +This file is part of GNU Emacs. + +GNU Emacs is free software: you can redistribute it and/or modify +it under the terms of the GNU General Public License as published by +the Free Software Foundation, either version 3 of the License, or (at +your option) any later version. + +GNU Emacs is distributed in the hope that it will be useful, +but WITHOUT ANY WARRANTY; without even the implied warranty of +MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the +GNU General Public License for more details. + +You should have received a copy of the GNU General Public License +along with GNU Emacs. If not, see <https://www.gnu.org/licenses/>. */ + +#include <config.h> + +#include "systime.h" + +#include "blockinput.h" +#include "coding.h" +#include "lisp.h" + +#include <strftime.h> + +#include <errno.h> +#include <math.h> +#include <stdio.h> +#include <stdlib.h> + +#ifdef HAVE_TIMEZONE_T +# include <sys/param.h> +# if defined __NetBSD_Version__ && __NetBSD_Version__ < 700000000 +# define HAVE_TZALLOC_BUG true +# endif +#endif +#ifndef HAVE_TZALLOC_BUG +# define HAVE_TZALLOC_BUG false +#endif + +#define TM_YEAR_BASE 1900 + +#ifndef HAVE_TM_GMTOFF +# define HAVE_TM_GMTOFF false +#endif + +#ifndef TIME_T_MIN +# define TIME_T_MIN TYPE_MINIMUM (time_t) +#endif +#ifndef TIME_T_MAX +# define TIME_T_MAX TYPE_MAXIMUM (time_t) +#endif + +/* Return a struct timeval that is roughly equivalent to T. + Use the least timeval not less than T. + Return an extremal value if the result would overflow. */ +struct timeval +make_timeval (struct timespec t) +{ + struct timeval tv; + tv.tv_sec = t.tv_sec; + tv.tv_usec = t.tv_nsec / 1000; + + if (t.tv_nsec % 1000 != 0) + { + if (tv.tv_usec < 999999) + tv.tv_usec++; + else if (tv.tv_sec < TYPE_MAXIMUM (time_t)) + { + tv.tv_sec++; + tv.tv_usec = 0; + } + } + + return tv; +} + +/* Yield A's UTC offset, or an unspecified value if unknown. */ +static long int +tm_gmtoff (struct tm *a) +{ +#if HAVE_TM_GMTOFF + return a->tm_gmtoff; +#else + return 0; +#endif +} + +/* Yield A - B, measured in seconds. + This function is copied from the GNU C Library. */ +static int +tm_diff (struct tm *a, struct tm *b) +{ + /* Compute intervening leap days correctly even if year is negative. + Take care to avoid int overflow in leap day calculations, + but it's OK to assume that A and B are close to each other. */ + int a4 = (a->tm_year >> 2) + (TM_YEAR_BASE >> 2) - ! (a->tm_year & 3); + int b4 = (b->tm_year >> 2) + (TM_YEAR_BASE >> 2) - ! (b->tm_year & 3); + int a100 = a4 / 25 - (a4 % 25 < 0); + int b100 = b4 / 25 - (b4 % 25 < 0); + int a400 = a100 >> 2; + int b400 = b100 >> 2; + int intervening_leap_days = (a4 - b4) - (a100 - b100) + (a400 - b400); + int years = a->tm_year - b->tm_year; + int days = (365 * years + intervening_leap_days + + (a->tm_yday - b->tm_yday)); + return (60 * (60 * (24 * days + (a->tm_hour - b->tm_hour)) + + (a->tm_min - b->tm_min)) + + (a->tm_sec - b->tm_sec)); +} + +enum { tzeqlen = sizeof "TZ=" - 1 }; + +/* Time zones equivalent to current local time and to UTC, respectively. */ +static timezone_t local_tz; +static timezone_t const utc_tz = 0; + +static struct tm * +emacs_localtime_rz (timezone_t tz, time_t const *t, struct tm *tm) +{ + tm = localtime_rz (tz, t, tm); + if (!tm && errno == ENOMEM) + memory_full (SIZE_MAX); + return tm; +} + +static time_t +emacs_mktime_z (timezone_t tz, struct tm *tm) +{ + errno = 0; + time_t t = mktime_z (tz, tm); + if (t == (time_t) -1 && errno == ENOMEM) + memory_full (SIZE_MAX); + return t; +} + +static _Noreturn void +invalid_time_zone_specification (Lisp_Object zone) +{ + xsignal2 (Qerror, build_string ("Invalid time zone specification"), zone); +} + +/* Free a timezone, except do not free the time zone for local time. + Freeing utc_tz is also a no-op. */ +static void +xtzfree (timezone_t tz) +{ + if (tz != local_tz) + tzfree (tz); +} + +/* Convert the Lisp time zone rule ZONE to a timezone_t object. + The returned value either is 0, or is LOCAL_TZ, or is newly allocated. + If SETTZ, set Emacs local time to the time zone rule; otherwise, + the caller should eventually pass the returned value to xtzfree. */ +static timezone_t +tzlookup (Lisp_Object zone, bool settz) +{ + static char const tzbuf_format[] = "<%+.*"pI"d>%s%"pI"d:%02d:%02d"; + char const *trailing_tzbuf_format = tzbuf_format + sizeof "<%+.*"pI"d" - 1; + char tzbuf[sizeof tzbuf_format + 2 * INT_STRLEN_BOUND (EMACS_INT)]; + char const *zone_string; + timezone_t new_tz; + + if (NILP (zone)) + return local_tz; + else if (EQ (zone, Qt) || EQ (zone, make_fixnum (0))) + { + zone_string = "UTC0"; + new_tz = utc_tz; + } + else + { + bool plain_integer = FIXNUMP (zone); + + if (EQ (zone, Qwall)) + zone_string = 0; + else if (STRINGP (zone)) + zone_string = SSDATA (ENCODE_SYSTEM (zone)); + else if (plain_integer || (CONSP (zone) && FIXNUMP (XCAR (zone)) + && CONSP (XCDR (zone)))) + { + Lisp_Object abbr UNINIT; + if (!plain_integer) + { + abbr = XCAR (XCDR (zone)); + zone = XCAR (zone); + } + + EMACS_INT abszone = eabs (XFIXNUM (zone)), hour = abszone / (60 * 60); + int hour_remainder = abszone % (60 * 60); + int min = hour_remainder / 60, sec = hour_remainder % 60; + + if (plain_integer) + { + int prec = 2; + EMACS_INT numzone = hour; + if (hour_remainder != 0) + { + prec += 2, numzone = 100 * numzone + min; + if (sec != 0) + prec += 2, numzone = 100 * numzone + sec; + } + sprintf (tzbuf, tzbuf_format, prec, + XFIXNUM (zone) < 0 ? -numzone : numzone, + &"-"[XFIXNUM (zone) < 0], hour, min, sec); + zone_string = tzbuf; + } + else + { + AUTO_STRING (leading, "<"); + AUTO_STRING_WITH_LEN (trailing, tzbuf, + sprintf (tzbuf, trailing_tzbuf_format, + &"-"[XFIXNUM (zone) < 0], + hour, min, sec)); + zone_string = SSDATA (concat3 (leading, ENCODE_SYSTEM (abbr), + trailing)); + } + } + else + invalid_time_zone_specification (zone); + + new_tz = tzalloc (zone_string); + + if (HAVE_TZALLOC_BUG && !new_tz && errno != ENOMEM && plain_integer + && XFIXNUM (zone) % (60 * 60) == 0) + { + /* tzalloc mishandles POSIX strings; fall back on tzdb if + possible (Bug#30738). */ + sprintf (tzbuf, "Etc/GMT%+"pI"d", - (XFIXNUM (zone) / (60 * 60))); + new_tz = tzalloc (zone_string); + } + + if (!new_tz) + { + if (errno == ENOMEM) + memory_full (SIZE_MAX); + invalid_time_zone_specification (zone); + } + } + + if (settz) + { + block_input (); + emacs_setenv_TZ (zone_string); + tzset (); + timezone_t old_tz = local_tz; + local_tz = new_tz; + tzfree (old_tz); + unblock_input (); + } + + return new_tz; +} + +void +init_timefns (bool dumping) +{ +#ifndef CANNOT_DUMP + /* A valid but unlikely setting for the TZ environment variable. + It is OK (though a bit slower) if the user chooses this value. */ + static char dump_tz_string[] = "TZ=UtC0"; + + /* When just dumping out, set the time zone to a known unlikely value + and skip the rest of this function. */ + if (dumping) + { + xputenv (dump_tz_string); + tzset (); + return; + } +#endif + + char *tz = getenv ("TZ"); + +#if !defined CANNOT_DUMP + /* If the execution TZ happens to be the same as the dump TZ, + change it to some other value and then change it back, + to force the underlying implementation to reload the TZ info. + This is needed on implementations that load TZ info from files, + since the TZ file contents may differ between dump and execution. */ + if (tz && strcmp (tz, &dump_tz_string[tzeqlen]) == 0) + { + ++*tz; + tzset (); + --*tz; + } +#endif + + /* Set the time zone rule now, so that the call to putenv is done + before multiple threads are active. */ + tzlookup (tz ? build_string (tz) : Qwall, true); +} + +/* Report that a time value is out of range for Emacs. */ +void +time_overflow (void) +{ + error ("Specified time is not representable"); +} + +static _Noreturn void +invalid_time (void) +{ + error ("Invalid time specification"); +} + +/* Check a return value compatible with that of decode_time_components. */ +static void +check_time_validity (int validity) +{ + if (validity <= 0) + { + if (validity < 0) + time_overflow (); + else + invalid_time (); + } +} + +/* Return the upper part of the time T (everything but the bottom 16 bits). */ +static EMACS_INT +hi_time (time_t t) +{ + time_t hi = t >> LO_TIME_BITS; + if (FIXNUM_OVERFLOW_P (hi)) + time_overflow (); + return hi; +} + +/* Return the bottom bits of the time T. */ +static int +lo_time (time_t t) +{ + return t & ((1 << LO_TIME_BITS) - 1); +} + +/* Decode a Lisp list SPECIFIED_TIME that represents a time. + Set *PHIGH, *PLOW, *PUSEC, *PPSEC to its parts; do not check their values. + Return 2, 3, or 4 to indicate the effective length of SPECIFIED_TIME + if successful, 0 if unsuccessful. */ +static int +disassemble_lisp_time (Lisp_Object specified_time, Lisp_Object *phigh, + Lisp_Object *plow, Lisp_Object *pusec, + Lisp_Object *ppsec) +{ + Lisp_Object high = make_fixnum (0); + Lisp_Object low = specified_time; + Lisp_Object usec = make_fixnum (0); + Lisp_Object psec = make_fixnum (0); + int len = 4; + + if (CONSP (specified_time)) + { + high = XCAR (specified_time); + low = XCDR (specified_time); + if (CONSP (low)) + { + Lisp_Object low_tail = XCDR (low); + low = XCAR (low); + if (CONSP (low_tail)) + { + usec = XCAR (low_tail); + low_tail = XCDR (low_tail); + if (CONSP (low_tail)) + psec = XCAR (low_tail); + else + len = 3; + } + else if (!NILP (low_tail)) + { + usec = low_tail; + len = 3; + } + else + len = 2; + } + else + len = 2; + + /* When combining components, require LOW to be an integer, + as otherwise it would be a pain to add up times. */ + if (! INTEGERP (low)) + return 0; + } + else if (INTEGERP (specified_time)) + len = 2; + + *phigh = high; + *plow = low; + *pusec = usec; + *ppsec = psec; + return len; +} + +/* Convert T into an Emacs time *RESULT, truncating toward minus infinity. + Return true if T is in range, false otherwise. */ +static bool +decode_float_time (double t, struct lisp_time *result) +{ + double lo_multiplier = 1 << LO_TIME_BITS; + double emacs_time_min = MOST_NEGATIVE_FIXNUM * lo_multiplier; + if (! (emacs_time_min <= t && t < -emacs_time_min)) + return false; + + double small_t = t / lo_multiplier; + EMACS_INT hi = small_t; + double t_sans_hi = t - hi * lo_multiplier; + int lo = t_sans_hi; + long double fracps = (t_sans_hi - lo) * 1e12L; +#ifdef INT_FAST64_MAX + int_fast64_t ifracps = fracps; + int us = ifracps / 1000000; + int ps = ifracps % 1000000; +#else + int us = fracps / 1e6L; + int ps = fracps - us * 1e6L; +#endif + us -= (ps < 0); + ps += (ps < 0) * 1000000; + lo -= (us < 0); + us += (us < 0) * 1000000; + hi -= (lo < 0); + lo += (lo < 0) << LO_TIME_BITS; + result->hi = hi; + result->lo = lo; + result->us = us; + result->ps = ps; + return true; +} + +/* From the time components HIGH, LOW, USEC and PSEC taken from a Lisp + list, generate the corresponding time value. + If LOW is floating point, the other components should be zero. + + If RESULT is not null, store into *RESULT the converted time. + If *DRESULT is not null, store into *DRESULT the number of + seconds since the start of the POSIX Epoch. + + Return 1 if successful, 0 if the components are of the + wrong type, and -1 if the time is out of range. */ +int +decode_time_components (Lisp_Object high, Lisp_Object low, Lisp_Object usec, + Lisp_Object psec, + struct lisp_time *result, double *dresult) +{ + EMACS_INT hi, us, ps; + intmax_t lo; + if (! (FIXNUMP (high) + && FIXNUMP (usec) && FIXNUMP (psec))) + return 0; + if (! INTEGERP (low)) + { + if (FLOATP (low)) + { + double t = XFLOAT_DATA (low); + if (result && ! decode_float_time (t, result)) + return -1; + if (dresult) + *dresult = t; + return 1; + } + else if (NILP (low)) + { + struct timespec now = current_timespec (); + if (result) + { + result->hi = hi_time (now.tv_sec); + result->lo = lo_time (now.tv_sec); + result->us = now.tv_nsec / 1000; + result->ps = now.tv_nsec % 1000 * 1000; + } + if (dresult) + *dresult = now.tv_sec + now.tv_nsec / 1e9; + return 1; + } + else + return 0; + } + + hi = XFIXNUM (high); + if (! integer_to_intmax (low, &lo)) + return -1; + us = XFIXNUM (usec); + ps = XFIXNUM (psec); + + /* Normalize out-of-range lower-order components by carrying + each overflow into the next higher-order component. */ + us += ps / 1000000 - (ps % 1000000 < 0); + lo += us / 1000000 - (us % 1000000 < 0); + if (INT_ADD_WRAPV (lo >> LO_TIME_BITS, hi, &hi)) + return -1; + ps = ps % 1000000 + 1000000 * (ps % 1000000 < 0); + us = us % 1000000 + 1000000 * (us % 1000000 < 0); + lo &= (1 << LO_TIME_BITS) - 1; + + if (result) + { + if (FIXNUM_OVERFLOW_P (hi)) + return -1; + result->hi = hi; + result->lo = lo; + result->us = us; + result->ps = ps; + } + + if (dresult) + { + double dhi = hi; + *dresult = (us * 1e6 + ps) / 1e12 + lo + dhi * (1 << LO_TIME_BITS); + } + + return 1; +} + +struct timespec +lisp_to_timespec (struct lisp_time t) +{ + if (! ((TYPE_SIGNED (time_t) ? TIME_T_MIN >> LO_TIME_BITS <= t.hi : 0 <= t.hi) + && t.hi <= TIME_T_MAX >> LO_TIME_BITS)) + return invalid_timespec (); + time_t s = (t.hi << LO_TIME_BITS) + t.lo; + int ns = t.us * 1000 + t.ps / 1000; + return make_timespec (s, ns); +} + +/* Decode a Lisp list SPECIFIED_TIME that represents a time. + Store its effective length into *PLEN. + If SPECIFIED_TIME is nil, use the current time. + Signal an error if SPECIFIED_TIME does not represent a time. */ +static struct lisp_time +lisp_time_struct (Lisp_Object specified_time, int *plen) +{ + Lisp_Object high, low, usec, psec; + struct lisp_time t; + int len = disassemble_lisp_time (specified_time, &high, &low, &usec, &psec); + if (!len) + invalid_time (); + int val = decode_time_components (high, low, usec, psec, &t, 0); + check_time_validity (val); + *plen = len; + return t; +} + +/* Like lisp_time_struct, except return a struct timespec. + Discard any low-order digits. */ +struct timespec +lisp_time_argument (Lisp_Object specified_time) +{ + int len; + struct lisp_time lt = lisp_time_struct (specified_time, &len); + struct timespec t = lisp_to_timespec (lt); + if (! timespec_valid_p (t)) + time_overflow (); + return t; +} + +/* Like lisp_time_argument, except decode only the seconds part, + and do not check the subseconds part. */ +static time_t +lisp_seconds_argument (Lisp_Object specified_time) +{ + Lisp_Object high, low, usec, psec; + struct lisp_time t; + + int val = disassemble_lisp_time (specified_time, &high, &low, &usec, &psec); + if (val != 0) + { + val = decode_time_components (high, low, make_fixnum (0), + make_fixnum (0), &t, 0); + if (0 < val + && ! ((TYPE_SIGNED (time_t) + ? TIME_T_MIN >> LO_TIME_BITS <= t.hi + : 0 <= t.hi) + && t.hi <= TIME_T_MAX >> LO_TIME_BITS)) + val = -1; + } + check_time_validity (val); + return (t.hi << LO_TIME_BITS) + t.lo; +} + +static struct lisp_time +time_add (struct lisp_time ta, struct lisp_time tb) +{ + EMACS_INT hi = ta.hi + tb.hi; + int lo = ta.lo + tb.lo; + int us = ta.us + tb.us; + int ps = ta.ps + tb.ps; + us += (1000000 <= ps); + ps -= (1000000 <= ps) * 1000000; + lo += (1000000 <= us); + us -= (1000000 <= us) * 1000000; + hi += (1 << LO_TIME_BITS <= lo); + lo -= (1 << LO_TIME_BITS <= lo) << LO_TIME_BITS; + return (struct lisp_time) { hi, lo, us, ps }; +} + +static struct lisp_time +time_subtract (struct lisp_time ta, struct lisp_time tb) +{ + EMACS_INT hi = ta.hi - tb.hi; + int lo = ta.lo - tb.lo; + int us = ta.us - tb.us; + int ps = ta.ps - tb.ps; + us -= (ps < 0); + ps += (ps < 0) * 1000000; + lo -= (us < 0); + us += (us < 0) * 1000000; + hi -= (lo < 0); + lo += (lo < 0) << LO_TIME_BITS; + return (struct lisp_time) { hi, lo, us, ps }; +} + +static Lisp_Object +time_arith (Lisp_Object a, Lisp_Object b, bool subtract) +{ + if (FLOATP (a) && !isfinite (XFLOAT_DATA (a))) + { + double da = XFLOAT_DATA (a); + double db = XFLOAT_DATA (Ffloat_time (b)); + return make_float (subtract ? da - db : da + db); + } + if (FLOATP (b) && !isfinite (XFLOAT_DATA (b))) + return subtract ? make_float (-XFLOAT_DATA (b)) : b; + + int alen, blen; + struct lisp_time ta = lisp_time_struct (a, &alen); + struct lisp_time tb = lisp_time_struct (b, &blen); + struct lisp_time t = (subtract ? time_subtract : time_add) (ta, tb); + if (FIXNUM_OVERFLOW_P (t.hi)) + time_overflow (); + Lisp_Object val = Qnil; + + switch (max (alen, blen)) + { + default: + val = Fcons (make_fixnum (t.ps), val); + FALLTHROUGH; + case 3: + val = Fcons (make_fixnum (t.us), val); + FALLTHROUGH; + case 2: + val = Fcons (make_fixnum (t.lo), val); + val = Fcons (make_fixnum (t.hi), val); + break; + } + + return val; +} + +DEFUN ("time-add", Ftime_add, Stime_add, 2, 2, 0, + doc: /* Return the sum of two time values A and B, as a time value. +A nil value for either argument stands for the current time. +See `current-time-string' for the various forms of a time value. */) + (Lisp_Object a, Lisp_Object b) +{ + return time_arith (a, b, false); +} + +DEFUN ("time-subtract", Ftime_subtract, Stime_subtract, 2, 2, 0, + doc: /* Return the difference between two time values A and B, as a time value. +Use `float-time' to convert the difference into elapsed seconds. +A nil value for either argument stands for the current time. +See `current-time-string' for the various forms of a time value. */) + (Lisp_Object a, Lisp_Object b) +{ + return time_arith (a, b, true); +} + +/* Return negative, 0, positive if a < b, a == b, a > b respectively. + Return positive if either a or b is a NaN; this is good enough + for the current callers. */ +static int +time_cmp (Lisp_Object a, Lisp_Object b) +{ + if ((FLOATP (a) && !isfinite (XFLOAT_DATA (a))) + || (FLOATP (b) && !isfinite (XFLOAT_DATA (b)))) + { + double da = FLOATP (a) ? XFLOAT_DATA (a) : 0; + double db = FLOATP (b) ? XFLOAT_DATA (b) : 0; + return da < db ? -1 : da != db; + } + + int alen, blen; + struct lisp_time ta = lisp_time_struct (a, &alen); + struct lisp_time tb = lisp_time_struct (b, &blen); + return (ta.hi != tb.hi ? (ta.hi < tb.hi ? -1 : 1) + : ta.lo != tb.lo ? (ta.lo < tb.lo ? -1 : 1) + : ta.us != tb.us ? (ta.us < tb.us ? -1 : 1) + : ta.ps < tb.ps ? -1 : ta.ps != tb.ps); +} + +DEFUN ("time-less-p", Ftime_less_p, Stime_less_p, 2, 2, 0, + doc: /* Return non-nil if time value T1 is earlier than time value T2. +A nil value for either argument stands for the current time. +See `current-time-string' for the various forms of a time value. */) + (Lisp_Object t1, Lisp_Object t2) +{ + return time_cmp (t1, t2) < 0 ? Qt : Qnil; +} + +DEFUN ("time-equal-p", Ftime_equal_p, Stime_equal_p, 2, 2, 0, + doc: /* Return non-nil if T1 and T2 are equal time values. +A nil value for either argument stands for the current time. +See `current-time-string' for the various forms of a time value. */) + (Lisp_Object t1, Lisp_Object t2) +{ + return time_cmp (t1, t2) == 0 ? Qt : Qnil; +} + + +/* Make a Lisp list that represents the Emacs time T. T may be an + invalid time, with a slightly negative tv_nsec value such as + UNKNOWN_MODTIME_NSECS; in that case, the Lisp list contains a + correspondingly negative picosecond count. */ +Lisp_Object +make_lisp_time (struct timespec t) +{ + time_t s = t.tv_sec; + int ns = t.tv_nsec; + return list4i (hi_time (s), lo_time (s), ns / 1000, ns % 1000 * 1000); +} + +DEFUN ("float-time", Ffloat_time, Sfloat_time, 0, 1, 0, + doc: /* Return the current time, as a float number of seconds since the epoch. +If SPECIFIED-TIME is given, it is the time to convert to float +instead of the current time. The argument should have the form +\(HIGH LOW) or (HIGH LOW USEC) or (HIGH LOW USEC PSEC). Thus, +you can use times from `current-time' and from `file-attributes'. +SPECIFIED-TIME can also have the form (HIGH . LOW), but this is +considered obsolete. + +WARNING: Since the result is floating point, it may not be exact. +If precise time stamps are required, use either `current-time', +or (if you need time as a string) `format-time-string'. */) + (Lisp_Object specified_time) +{ + double t; + Lisp_Object high, low, usec, psec; + if (! (disassemble_lisp_time (specified_time, &high, &low, &usec, &psec) + && decode_time_components (high, low, usec, psec, 0, &t))) + invalid_time (); + return make_float (t); +} + +/* Write information into buffer S of size MAXSIZE, according to the + FORMAT of length FORMAT_LEN, using time information taken from *TP. + Use the time zone specified by TZ. + Use NS as the number of nanoseconds in the %N directive. + Return the number of bytes written, not including the terminating + '\0'. If S is NULL, nothing will be written anywhere; so to + determine how many bytes would be written, use NULL for S and + ((size_t) -1) for MAXSIZE. + + This function behaves like nstrftime, except it allows null + bytes in FORMAT and it does not support nanoseconds. */ +static size_t +emacs_nmemftime (char *s, size_t maxsize, const char *format, + size_t format_len, const struct tm *tp, timezone_t tz, int ns) +{ + size_t total = 0; + + /* Loop through all the null-terminated strings in the format + argument. Normally there's just one null-terminated string, but + there can be arbitrarily many, concatenated together, if the + format contains '\0' bytes. nstrftime stops at the first + '\0' byte so we must invoke it separately for each such string. */ + for (;;) + { + size_t len; + size_t result; + + if (s) + s[0] = '\1'; + + result = nstrftime (s, maxsize, format, tp, tz, ns); + + if (s) + { + if (result == 0 && s[0] != '\0') + return 0; + s += result + 1; + } + + maxsize -= result + 1; + total += result; + len = strlen (format); + if (len == format_len) + return total; + total++; + format += len + 1; + format_len -= len + 1; + } +} + +static Lisp_Object +format_time_string (char const *format, ptrdiff_t formatlen, + struct timespec t, Lisp_Object zone, struct tm *tmp) +{ + char buffer[4000]; + char *buf = buffer; + ptrdiff_t size = sizeof buffer; + size_t len; + int ns = t.tv_nsec; + USE_SAFE_ALLOCA; + + timezone_t tz = tzlookup (zone, false); + /* On some systems, like 32-bit MinGW, tv_sec of struct timespec is + a 64-bit type, but time_t is a 32-bit type. emacs_localtime_rz + expects a pointer to time_t value. */ + time_t tsec = t.tv_sec; + tmp = emacs_localtime_rz (tz, &tsec, tmp); + if (! tmp) + { + xtzfree (tz); + time_overflow (); + } + synchronize_system_time_locale (); + + while (true) + { + buf[0] = '\1'; + len = emacs_nmemftime (buf, size, format, formatlen, tmp, tz, ns); + if ((0 < len && len < size) || (len == 0 && buf[0] == '\0')) + break; + + /* Buffer was too small, so make it bigger and try again. */ + len = emacs_nmemftime (NULL, SIZE_MAX, format, formatlen, tmp, tz, ns); + if (STRING_BYTES_BOUND <= len) + { + xtzfree (tz); + string_overflow (); + } + size = len + 1; + buf = SAFE_ALLOCA (size); + } + + xtzfree (tz); + AUTO_STRING_WITH_LEN (bufstring, buf, len); + Lisp_Object result = code_convert_string_norecord (bufstring, + Vlocale_coding_system, 0); + SAFE_FREE (); + return result; +} + +DEFUN ("format-time-string", Fformat_time_string, Sformat_time_string, 1, 3, 0, + doc: /* Use FORMAT-STRING to format the time TIME, or now if omitted or nil. +TIME is specified as (HIGH LOW USEC PSEC), as returned by +`current-time' or `file-attributes'. It can also be a single integer +number of seconds since the epoch. The obsolete form (HIGH . LOW) is +also still accepted. + +The optional ZONE is omitted or nil for Emacs local time, t for +Universal Time, `wall' for system wall clock time, or a string as in +the TZ environment variable. It can also be a list (as from +`current-time-zone') or an integer (as from `decode-time') applied +without consideration for daylight saving time. + +The value is a copy of FORMAT-STRING, but with certain constructs replaced +by text that describes the specified date and time in TIME: + +%Y is the year, %y within the century, %C the century. +%G is the year corresponding to the ISO week, %g within the century. +%m is the numeric month. +%b and %h are the locale's abbreviated month name, %B the full name. + (%h is not supported on MS-Windows.) +%d is the day of the month, zero-padded, %e is blank-padded. +%u is the numeric day of week from 1 (Monday) to 7, %w from 0 (Sunday) to 6. +%a is the locale's abbreviated name of the day of week, %A the full name. +%U is the week number starting on Sunday, %W starting on Monday, + %V according to ISO 8601. +%j is the day of the year. + +%H is the hour on a 24-hour clock, %I is on a 12-hour clock, %k is like %H + only blank-padded, %l is like %I blank-padded. +%p is the locale's equivalent of either AM or PM. +%q is the calendar quarter (1–4). +%M is the minute (00-59). +%S is the second (00-59; 00-60 on platforms with leap seconds) +%s is the number of seconds since 1970-01-01 00:00:00 +0000. +%N is the nanosecond, %6N the microsecond, %3N the millisecond, etc. +%Z is the time zone abbreviation, %z is the numeric form. + +%c is the locale's date and time format. +%x is the locale's "preferred" date format. +%D is like "%m/%d/%y". +%F is the ISO 8601 date format (like "%Y-%m-%d"). + +%R is like "%H:%M", %T is like "%H:%M:%S", %r is like "%I:%M:%S %p". +%X is the locale's "preferred" time format. + +Finally, %n is a newline, %t is a tab, %% is a literal %, and +unrecognized %-sequences stand for themselves. + +Certain flags and modifiers are available with some format controls. +The flags are `_', `-', `^' and `#'. For certain characters X, +%_X is like %X, but padded with blanks; %-X is like %X, +but without padding. %^X is like %X, but with all textual +characters up-cased; %#X is like %X, but with letter-case of +all textual characters reversed. +%NX (where N stands for an integer) is like %X, +but takes up at least N (a number) positions. +The modifiers are `E' and `O'. For certain characters X, +%EX is a locale's alternative version of %X; +%OX is like %X, but uses the locale's number symbols. + +For example, to produce full ISO 8601 format, use "%FT%T%z". + +usage: (format-time-string FORMAT-STRING &optional TIME ZONE) */) + (Lisp_Object format_string, Lisp_Object timeval, Lisp_Object zone) +{ + struct timespec t = lisp_time_argument (timeval); + struct tm tm; + + CHECK_STRING (format_string); + format_string = code_convert_string_norecord (format_string, + Vlocale_coding_system, 1); + return format_time_string (SSDATA (format_string), SBYTES (format_string), + t, zone, &tm); +} + +DEFUN ("decode-time", Fdecode_time, Sdecode_time, 0, 2, 0, + doc: /* Decode a time value as (SEC MINUTE HOUR DAY MONTH YEAR DOW DST UTCOFF). +The optional TIME should be a list of (HIGH LOW . IGNORED), +as from `current-time' and `file-attributes', or nil to use the +current time. It can also be a single integer number of seconds since +the epoch. The obsolete form (HIGH . LOW) is also still accepted. + +The optional ZONE is omitted or nil for Emacs local time, t for +Universal Time, `wall' for system wall clock time, or a string as in +the TZ environment variable. It can also be a list (as from +`current-time-zone') or an integer (the UTC offset in seconds) applied +without consideration for daylight saving time. + +The list has the following nine members: SEC is an integer between 0 +and 60; SEC is 60 for a leap second, which only some operating systems +support. MINUTE is an integer between 0 and 59. HOUR is an integer +between 0 and 23. DAY is an integer between 1 and 31. MONTH is an +integer between 1 and 12. YEAR is an integer indicating the +four-digit year. DOW is the day of week, an integer between 0 and 6, +where 0 is Sunday. DST is t if daylight saving time is in effect, +nil if it is not in effect, and -1 if daylight saving information is +not available. UTCOFF is an integer indicating the UTC offset in +seconds, i.e., the number of seconds east of Greenwich. (Note that +Common Lisp has different meanings for DOW and UTCOFF.) + +usage: (decode-time &optional TIME ZONE) */) + (Lisp_Object specified_time, Lisp_Object zone) +{ + time_t time_spec = lisp_seconds_argument (specified_time); + struct tm local_tm, gmt_tm; + timezone_t tz = tzlookup (zone, false); + struct tm *tm = emacs_localtime_rz (tz, &time_spec, &local_tm); + xtzfree (tz); + + if (! (tm + && MOST_NEGATIVE_FIXNUM - TM_YEAR_BASE <= local_tm.tm_year + && local_tm.tm_year <= MOST_POSITIVE_FIXNUM - TM_YEAR_BASE)) + time_overflow (); + + /* Avoid overflow when INT_MAX < EMACS_INT_MAX. */ + EMACS_INT tm_year_base = TM_YEAR_BASE; + + return CALLN (Flist, + make_fixnum (local_tm.tm_sec), + make_fixnum (local_tm.tm_min), + make_fixnum (local_tm.tm_hour), + make_fixnum (local_tm.tm_mday), + make_fixnum (local_tm.tm_mon + 1), + make_fixnum (local_tm.tm_year + tm_year_base), + make_fixnum (local_tm.tm_wday), + (local_tm.tm_isdst < 0 ? make_fixnum (-1) + : local_tm.tm_isdst == 0 ? Qnil : Qt), + (HAVE_TM_GMTOFF + ? make_fixnum (tm_gmtoff (&local_tm)) + : gmtime_r (&time_spec, &gmt_tm) + ? make_fixnum (tm_diff (&local_tm, &gmt_tm)) + : Qnil)); +} + +/* Return OBJ - OFFSET, checking that OBJ is a valid fixnum and that + the result is representable as an int. */ +static int +check_tm_member (Lisp_Object obj, int offset) +{ + CHECK_FIXNUM (obj); + EMACS_INT n = XFIXNUM (obj); + int result; + if (INT_SUBTRACT_WRAPV (n, offset, &result)) + time_overflow (); + return result; +} + +DEFUN ("encode-time", Fencode_time, Sencode_time, 6, MANY, 0, + doc: /* Convert SECOND, MINUTE, HOUR, DAY, MONTH, YEAR and ZONE to internal time. +This is the reverse operation of `decode-time', which see. + +The optional ZONE is omitted or nil for Emacs local time, t for +Universal Time, `wall' for system wall clock time, or a string as in +the TZ environment variable. It can also be a list (as from +`current-time-zone') or an integer (as from `decode-time') applied +without consideration for daylight saving time. + +You can pass more than 7 arguments; then the first six arguments +are used as SECOND through YEAR, and the *last* argument is used as ZONE. +The intervening arguments are ignored. +This feature lets (apply \\='encode-time (decode-time ...)) work. + +Out-of-range values for SECOND, MINUTE, HOUR, DAY, or MONTH are allowed; +for example, a DAY of 0 means the day preceding the given month. +Year numbers less than 100 are treated just like other year numbers. +If you want them to stand for years in this century, you must do that yourself. + +Years before 1970 are not guaranteed to work. On some systems, +year values as low as 1901 do work. + +usage: (encode-time SECOND MINUTE HOUR DAY MONTH YEAR &optional ZONE) */) + (ptrdiff_t nargs, Lisp_Object *args) +{ + time_t value; + struct tm tm; + Lisp_Object zone = (nargs > 6 ? args[nargs - 1] : Qnil); + + tm.tm_sec = check_tm_member (args[0], 0); + tm.tm_min = check_tm_member (args[1], 0); + tm.tm_hour = check_tm_member (args[2], 0); + tm.tm_mday = check_tm_member (args[3], 0); + tm.tm_mon = check_tm_member (args[4], 1); + tm.tm_year = check_tm_member (args[5], TM_YEAR_BASE); + tm.tm_isdst = -1; + + timezone_t tz = tzlookup (zone, false); + value = emacs_mktime_z (tz, &tm); + xtzfree (tz); + + if (value == (time_t) -1) + time_overflow (); + + return list2i (hi_time (value), lo_time (value)); +} + +DEFUN ("current-time", Fcurrent_time, Scurrent_time, 0, 0, 0, + doc: /* Return the current time, as the number of seconds since 1970-01-01 00:00:00. +The time is returned as a list of integers (HIGH LOW USEC PSEC). +HIGH has the most significant bits of the seconds, while LOW has the +least significant 16 bits. USEC and PSEC are the microsecond and +picosecond counts. */) + (void) +{ + return make_lisp_time (current_timespec ()); +} + +DEFUN ("current-time-string", Fcurrent_time_string, Scurrent_time_string, + 0, 2, 0, + doc: /* Return the current local time, as a human-readable string. +Programs can use this function to decode a time, +since the number of columns in each field is fixed +if the year is in the range 1000-9999. +The format is `Sun Sep 16 01:03:52 1973'. +However, see also the functions `decode-time' and `format-time-string' +which provide a much more powerful and general facility. + +If SPECIFIED-TIME is given, it is a time to format instead of the +current time. The argument should have the form (HIGH LOW . IGNORED). +Thus, you can use times obtained from `current-time' and from +`file-attributes'. SPECIFIED-TIME can also be a single integer number +of seconds since the epoch. The obsolete form (HIGH . LOW) is also +still accepted. + +The optional ZONE is omitted or nil for Emacs local time, t for +Universal Time, `wall' for system wall clock time, or a string as in +the TZ environment variable. It can also be a list (as from +`current-time-zone') or an integer (as from `decode-time') applied +without consideration for daylight saving time. */) + (Lisp_Object specified_time, Lisp_Object zone) +{ + time_t value = lisp_seconds_argument (specified_time); + timezone_t tz = tzlookup (zone, false); + + /* Convert to a string in ctime format, except without the trailing + newline, and without the 4-digit year limit. Don't use asctime + or ctime, as they might dump core if the year is outside the + range -999 .. 9999. */ + struct tm tm; + struct tm *tmp = emacs_localtime_rz (tz, &value, &tm); + xtzfree (tz); + if (! tmp) + time_overflow (); + + static char const wday_name[][4] = + { "Sun", "Mon", "Tue", "Wed", "Thu", "Fri", "Sat" }; + static char const mon_name[][4] = + { "Jan", "Feb", "Mar", "Apr", "May", "Jun", + "Jul", "Aug", "Sep", "Oct", "Nov", "Dec" }; + printmax_t year_base = TM_YEAR_BASE; + char buf[sizeof "Mon Apr 30 12:49:17 " + INT_STRLEN_BOUND (int) + 1]; + int len = sprintf (buf, "%s %s%3d %02d:%02d:%02d %"pMd, + wday_name[tm.tm_wday], mon_name[tm.tm_mon], tm.tm_mday, + tm.tm_hour, tm.tm_min, tm.tm_sec, + tm.tm_year + year_base); + + return make_unibyte_string (buf, len); +} + +DEFUN ("current-time-zone", Fcurrent_time_zone, Scurrent_time_zone, 0, 2, 0, + doc: /* Return the offset and name for the local time zone. +This returns a list of the form (OFFSET NAME). +OFFSET is an integer number of seconds ahead of UTC (east of Greenwich). + A negative value means west of Greenwich. +NAME is a string giving the name of the time zone. +If SPECIFIED-TIME is given, the time zone offset is determined from it +instead of using the current time. The argument should have the form +\(HIGH LOW . IGNORED). Thus, you can use times obtained from +`current-time' and from `file-attributes'. SPECIFIED-TIME can also be +a single integer number of seconds since the epoch. The obsolete form +(HIGH . LOW) is also still accepted. + +The optional ZONE is omitted or nil for Emacs local time, t for +Universal Time, `wall' for system wall clock time, or a string as in +the TZ environment variable. It can also be a list (as from +`current-time-zone') or an integer (as from `decode-time') applied +without consideration for daylight saving time. + +Some operating systems cannot provide all this information to Emacs; +in this case, `current-time-zone' returns a list containing nil for +the data it can't find. */) + (Lisp_Object specified_time, Lisp_Object zone) +{ + struct timespec value; + struct tm local_tm, gmt_tm; + Lisp_Object zone_offset, zone_name; + + zone_offset = Qnil; + value = make_timespec (lisp_seconds_argument (specified_time), 0); + zone_name = format_time_string ("%Z", sizeof "%Z" - 1, value, + zone, &local_tm); + + /* gmtime_r expects a pointer to time_t, but tv_sec of struct + timespec on some systems (MinGW) is a 64-bit field. */ + time_t tsec = value.tv_sec; + if (HAVE_TM_GMTOFF || gmtime_r (&tsec, &gmt_tm)) + { + long int offset = (HAVE_TM_GMTOFF + ? tm_gmtoff (&local_tm) + : tm_diff (&local_tm, &gmt_tm)); + zone_offset = make_fixnum (offset); + if (SCHARS (zone_name) == 0) + { + /* No local time zone name is available; use numeric zone instead. */ + long int hour = offset / 3600; + int min_sec = offset % 3600; + int amin_sec = min_sec < 0 ? - min_sec : min_sec; + int min = amin_sec / 60; + int sec = amin_sec % 60; + int min_prec = min_sec ? 2 : 0; + int sec_prec = sec ? 2 : 0; + char buf[sizeof "+0000" + INT_STRLEN_BOUND (long int)]; + zone_name = make_formatted_string (buf, "%c%.2ld%.*d%.*d", + (offset < 0 ? '-' : '+'), + hour, min_prec, min, sec_prec, sec); + } + } + + return list2 (zone_offset, zone_name); +} + +DEFUN ("set-time-zone-rule", Fset_time_zone_rule, Sset_time_zone_rule, 1, 1, 0, + doc: /* Set the Emacs local time zone using TZ, a string specifying a time zone rule. +If TZ is nil or `wall', use system wall clock time; this differs from +the usual Emacs convention where nil means current local time. If TZ +is t, use Universal Time. If TZ is a list (as from +`current-time-zone') or an integer (as from `decode-time'), use the +specified time zone without consideration for daylight saving time. + +Instead of calling this function, you typically want something else. +To temporarily use a different time zone rule for just one invocation +of `decode-time', `encode-time', or `format-time-string', pass the +function a ZONE argument. To change local time consistently +throughout Emacs, call (setenv "TZ" TZ): this changes both the +environment of the Emacs process and the variable +`process-environment', whereas `set-time-zone-rule' affects only the +former. */) + (Lisp_Object tz) +{ + tzlookup (NILP (tz) ? Qwall : tz, true); + return Qnil; +} + +/* A buffer holding a string of the form "TZ=value", intended + to be part of the environment. If TZ is supposed to be unset, + the buffer string is "tZ=". */ + static char *tzvalbuf; + +/* Get the local time zone rule. */ +char * +emacs_getenv_TZ (void) +{ + return tzvalbuf[0] == 'T' ? tzvalbuf + tzeqlen : 0; +} + +/* Set the local time zone rule to TZSTRING, which can be null to + denote wall clock time. Do not record the setting in LOCAL_TZ. + + This function is not thread-safe, in theory because putenv is not, + but mostly because of the static storage it updates. Other threads + that invoke localtime etc. may be adversely affected while this + function is executing. */ + +int +emacs_setenv_TZ (const char *tzstring) +{ + static ptrdiff_t tzvalbufsize; + ptrdiff_t tzstringlen = tzstring ? strlen (tzstring) : 0; + char *tzval = tzvalbuf; + bool new_tzvalbuf = tzvalbufsize <= tzeqlen + tzstringlen; + + if (new_tzvalbuf) + { + /* Do not attempt to free the old tzvalbuf, since another thread + may be using it. In practice, the first allocation is large + enough and memory does not leak. */ + tzval = xpalloc (NULL, &tzvalbufsize, + tzeqlen + tzstringlen - tzvalbufsize + 1, -1, 1); + tzvalbuf = tzval; + tzval[1] = 'Z'; + tzval[2] = '='; + } + + if (tzstring) + { + /* Modify TZVAL in place. Although this is dicey in a + multithreaded environment, we know of no portable alternative. + Calling putenv or setenv could crash some other thread. */ + tzval[0] = 'T'; + strcpy (tzval + tzeqlen, tzstring); + } + else + { + /* Turn 'TZ=whatever' into an empty environment variable 'tZ='. + Although this is also dicey, calling unsetenv here can crash Emacs. + See Bug#8705. */ + tzval[0] = 't'; + tzval[tzeqlen] = 0; + } + + +#ifndef WINDOWSNT + /* Modifying *TZVAL merely requires calling tzset (which is the + caller's responsibility). However, modifying TZVAL requires + calling putenv; although this is not thread-safe, in practice this + runs only on startup when there is only one thread. */ + bool need_putenv = new_tzvalbuf; +#else + /* MS-Windows 'putenv' copies the argument string into a block it + allocates, so modifying *TZVAL will not change the environment. + However, the other threads run by Emacs on MS-Windows never call + 'xputenv' or 'putenv' or 'unsetenv', so the original cause for the + dicey in-place modification technique doesn't exist there in the + first place. */ + bool need_putenv = true; +#endif + if (need_putenv) + xputenv (tzval); + + return 0; +} + +void +syms_of_timefns (void) +{ + defsubr (&Scurrent_time); + defsubr (&Stime_add); + defsubr (&Stime_subtract); + defsubr (&Stime_less_p); + defsubr (&Stime_equal_p); + defsubr (&Sformat_time_string); + defsubr (&Sfloat_time); + defsubr (&Sdecode_time); + defsubr (&Sencode_time); + defsubr (&Scurrent_time_string); + defsubr (&Scurrent_time_zone); + defsubr (&Sset_time_zone_rule); +} |