summaryrefslogtreecommitdiff
path: root/src/timefns.c
diff options
context:
space:
mode:
Diffstat (limited to 'src/timefns.c')
-rw-r--r--src/timefns.c2021
1 files changed, 2021 insertions, 0 deletions
diff --git a/src/timefns.c b/src/timefns.c
new file mode 100644
index 00000000000..6c9473f22a6
--- /dev/null
+++ b/src/timefns.c
@@ -0,0 +1,2021 @@
+/* Timestamp functions for Emacs
+
+Copyright (C) 1985-1987, 1989, 1993-2019 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 "bignum.h"
+#include "coding.h"
+#include "lisp.h"
+#include "pdumper.h"
+
+#include <strftime.h>
+
+#include <errno.h>
+#include <limits.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
+
+enum { 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
+
+/* Compile with -DFASTER_TIMEFNS=0 to disable common optimizations and
+ allow easier testing of some slow-path code. */
+#ifndef FASTER_TIMEFNS
+# define FASTER_TIMEFNS 1
+#endif
+
+/* Whether to warn about Lisp timestamps (TICKS . HZ) that may be
+ instances of obsolete-format timestamps (HI . LO) where HI is
+ the high-order bits and LO the low-order 16 bits. Currently this
+ is true, but it should change to false in a future version of
+ Emacs. Compile with -DWARN_OBSOLETE_TIMESTAMPS=0 to see what the
+ future will be like. */
+#ifndef WARN_OBSOLETE_TIMESTAMPS
+enum { WARN_OBSOLETE_TIMESTAMPS = true };
+#endif
+
+/* Although current-time etc. generate list-format timestamps
+ (HI LO US PS), the plan is to change these functions to generate
+ frequency-based timestamps (TICKS . HZ) in a future release.
+ To try this now, compile with -DCURRENT_TIME_LIST=0. */
+#ifndef CURRENT_TIME_LIST
+enum { CURRENT_TIME_LIST = true };
+#endif
+
+#if FIXNUM_OVERFLOW_P (1000000000)
+static Lisp_Object timespec_hz;
+#else
+# define timespec_hz make_fixnum (TIMESPEC_HZ)
+#endif
+
+#define TRILLION 1000000000000
+#if FIXNUM_OVERFLOW_P (TRILLION)
+static Lisp_Object trillion;
+# define ztrillion (*xbignum_val (trillion))
+#else
+# define trillion make_fixnum (TRILLION)
+# if ULONG_MAX < TRILLION || !FASTER_TIMEFNS
+mpz_t ztrillion;
+# endif
+#endif
+
+/* True if the nonzero Lisp integer HZ divides evenly into a trillion. */
+static bool
+trillion_factor (Lisp_Object hz)
+{
+ if (FASTER_TIMEFNS)
+ {
+ if (FIXNUMP (hz))
+ return TRILLION % XFIXNUM (hz) == 0;
+ if (!FIXNUM_OVERFLOW_P (TRILLION))
+ return false;
+ }
+ verify (TRILLION <= INTMAX_MAX);
+ intmax_t ihz;
+ return integer_to_intmax (hz, &ihz) && TRILLION % ihz == 0;
+}
+
+/* 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 < TIME_T_MAX)
+ {
+ 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 AVOID
+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 (void)
+{
+#ifdef HAVE_UNEXEC
+ /* 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 (will_dump_with_unexec_p ())
+ {
+ xputenv (dump_tz_string);
+ tzset ();
+ return;
+ }
+#endif
+
+ char *tz = getenv ("TZ");
+
+#ifdef HAVE_UNEXEC
+ /* 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 AVOID
+time_error (int err)
+{
+ switch (err)
+ {
+ case ENOMEM: memory_full (SIZE_MAX);
+ case EOVERFLOW: time_overflow ();
+ default: error ("Invalid time specification");
+ }
+}
+
+static AVOID
+invalid_hz (Lisp_Object hz)
+{
+ xsignal2 (Qerror, build_string ("Invalid time frequency"), hz);
+}
+
+/* Return the upper part of the time T (everything but the bottom 16 bits). */
+static Lisp_Object
+hi_time (time_t t)
+{
+ return INT_TO_INTEGER (t >> LO_TIME_BITS);
+}
+
+/* Return the bottom bits of the time T. */
+static Lisp_Object
+lo_time (time_t t)
+{
+ return make_fixnum (t & ((1 << LO_TIME_BITS) - 1));
+}
+
+/* When converting a double to a fraction TICKS / HZ, HZ is equal to
+ FLT_RADIX * P where 0 <= P < FLT_RADIX_POWER_SIZE. The tiniest
+ nonzero double uses the maximum P. */
+enum { flt_radix_power_size = DBL_MANT_DIG - DBL_MIN_EXP + 1 };
+
+/* A integer vector of size flt_radix_power_size. The Pth entry
+ equals FLT_RADIX**P. */
+static Lisp_Object flt_radix_power;
+
+/* Convert T into an Emacs time *RESULT, truncating toward minus infinity.
+ Return zero if successful, an error number otherwise. */
+static int
+decode_float_time (double t, struct lisp_time *result)
+{
+ Lisp_Object ticks, hz;
+ if (t == 0)
+ {
+ ticks = make_fixnum (0);
+ hz = make_fixnum (1);
+ }
+ else
+ {
+ int exponent = ilogb (t);
+ int scale;
+ if (exponent < DBL_MANT_DIG)
+ {
+ if (exponent < DBL_MIN_EXP - 1)
+ {
+ if (exponent == FP_ILOGBNAN
+ && (FP_ILOGBNAN != FP_ILOGB0 || isnan (t)))
+ return EINVAL;
+ /* T is tiny. SCALE must be less than FLT_RADIX_POWER_SIZE,
+ as otherwise T would be scaled as if it were normalized. */
+ scale = flt_radix_power_size - 1;
+ }
+ else
+ {
+ /* The typical case. */
+ scale = DBL_MANT_DIG - 1 - exponent;
+ }
+ }
+ else if (exponent < INT_MAX)
+ {
+ /* T is finite but so large that HZ would be less than 1 if
+ T's precision were represented exactly. SCALE must be
+ nonnegative, as the (TICKS . HZ) representation requires
+ HZ to be at least 1. So use SCALE = 0, which converts T to
+ (T . 1), which is the exact numeric value with too-large HZ,
+ which is typically better than signaling overflow. */
+ scale = 0;
+ }
+ else
+ return FP_ILOGBNAN == INT_MAX && isnan (t) ? EINVAL : EOVERFLOW;
+
+ double scaled = scalbn (t, scale);
+ eassert (trunc (scaled) == scaled);
+ ticks = double_to_integer (scaled);
+ hz = AREF (flt_radix_power, scale);
+ if (NILP (hz))
+ {
+ mpz_ui_pow_ui (mpz[0], FLT_RADIX, scale);
+ hz = make_integer_mpz ();
+ ASET (flt_radix_power, scale, hz);
+ }
+ }
+ result->ticks = ticks;
+ result->hz = hz;
+ return 0;
+}
+
+/* Make a 4-element timestamp (HI LO US PS) from TICKS and HZ.
+ Drop any excess precision. */
+static Lisp_Object
+ticks_hz_list4 (Lisp_Object ticks, Lisp_Object hz)
+{
+ mpz_t const *zticks = bignum_integer (&mpz[0], ticks);
+#if FASTER_TIMEFNS && TRILLION <= ULONG_MAX
+ mpz_mul_ui (mpz[0], *zticks, TRILLION);
+#else
+ mpz_mul (mpz[0], *zticks, ztrillion);
+#endif
+ mpz_fdiv_q (mpz[0], mpz[0], *bignum_integer (&mpz[1], hz));
+#if FASTER_TIMEFNS && TRILLION <= ULONG_MAX
+ unsigned long int fullps = mpz_fdiv_q_ui (mpz[0], mpz[0], TRILLION);
+ int us = fullps / 1000000;
+ int ps = fullps % 1000000;
+#else
+ mpz_fdiv_qr (mpz[0], mpz[1], mpz[0], ztrillion);
+ int ps = mpz_fdiv_q_ui (mpz[1], mpz[1], 1000000);
+ int us = mpz_get_ui (mpz[1]);
+#endif
+ unsigned long ulo = mpz_get_ui (mpz[0]);
+ if (mpz_sgn (mpz[0]) < 0)
+ ulo = -ulo;
+ int lo = ulo & ((1 << LO_TIME_BITS) - 1);
+ mpz_fdiv_q_2exp (mpz[0], mpz[0], LO_TIME_BITS);
+ return list4 (make_integer_mpz (), make_fixnum (lo),
+ make_fixnum (us), make_fixnum (ps));
+}
+
+/* Set ROP to T. */
+static void
+mpz_set_time (mpz_t rop, time_t t)
+{
+ if (EXPR_SIGNED (t))
+ mpz_set_intmax (rop, t);
+ else
+ mpz_set_uintmax (rop, t);
+}
+
+/* Store into mpz[0] a clock tick count for T, assuming a
+ TIMESPEC_HZ-frequency clock. Use mpz[1] as a temp. */
+static void
+timespec_mpz (struct timespec t)
+{
+ mpz_set_ui (mpz[0], t.tv_nsec);
+ mpz_set_time (mpz[1], t.tv_sec);
+ mpz_addmul_ui (mpz[0], mpz[1], TIMESPEC_HZ);
+}
+
+/* Convert T to a Lisp integer counting TIMESPEC_HZ ticks. */
+static Lisp_Object
+timespec_ticks (struct timespec t)
+{
+ intmax_t accum;
+ if (FASTER_TIMEFNS
+ && !INT_MULTIPLY_WRAPV (t.tv_sec, TIMESPEC_HZ, &accum)
+ && !INT_ADD_WRAPV (t.tv_nsec, accum, &accum))
+ return make_int (accum);
+ timespec_mpz (t);
+ return make_integer_mpz ();
+}
+
+/* Convert T to a Lisp integer counting HZ ticks, taking the floor.
+ Assume T is valid, but check HZ. */
+static Lisp_Object
+lisp_time_hz_ticks (struct lisp_time t, Lisp_Object hz)
+{
+ if (FASTER_TIMEFNS && EQ (t.hz, hz))
+ return t.ticks;
+ if (FIXNUMP (hz))
+ {
+ if (XFIXNUM (hz) <= 0)
+ invalid_hz (hz);
+ intmax_t ticks;
+ if (FASTER_TIMEFNS && FIXNUMP (t.ticks) && FIXNUMP (t.hz)
+ && !INT_MULTIPLY_WRAPV (XFIXNUM (t.ticks), XFIXNUM (hz), &ticks))
+ return make_int (ticks / XFIXNUM (t.hz)
+ - (ticks % XFIXNUM (t.hz) < 0));
+ }
+ else if (! (BIGNUMP (hz) && 0 < mpz_sgn (*xbignum_val (hz))))
+ invalid_hz (hz);
+
+ mpz_mul (mpz[0],
+ *bignum_integer (&mpz[0], t.ticks),
+ *bignum_integer (&mpz[1], hz));
+ mpz_fdiv_q (mpz[0], mpz[0], *bignum_integer (&mpz[1], t.hz));
+ return make_integer_mpz ();
+}
+
+/* Convert T to a Lisp integer counting seconds, taking the floor. */
+static Lisp_Object
+lisp_time_seconds (struct lisp_time t)
+{
+ if (!FASTER_TIMEFNS)
+ return lisp_time_hz_ticks (t, make_fixnum (1));
+ if (FIXNUMP (t.ticks) && FIXNUMP (t.hz))
+ return make_fixnum (XFIXNUM (t.ticks) / XFIXNUM (t.hz)
+ - (XFIXNUM (t.ticks) % XFIXNUM (t.hz) < 0));
+ mpz_fdiv_q (mpz[0],
+ *bignum_integer (&mpz[0], t.ticks),
+ *bignum_integer (&mpz[1], t.hz));
+ return make_integer_mpz ();
+}
+
+/* Convert T to a Lisp timestamp. */
+Lisp_Object
+make_lisp_time (struct timespec t)
+{
+ if (CURRENT_TIME_LIST)
+ {
+ time_t s = t.tv_sec;
+ int ns = t.tv_nsec;
+ return list4 (hi_time (s), lo_time (s),
+ make_fixnum (ns / 1000), make_fixnum (ns % 1000 * 1000));
+ }
+ else
+ return timespec_to_lisp (t);
+}
+
+/* Return (TICKS . HZ) for time T. */
+Lisp_Object
+timespec_to_lisp (struct timespec t)
+{
+ return Fcons (timespec_ticks (t), timespec_hz);
+}
+
+/* Return NUMERATOR / DENOMINATOR, rounded to the nearest double.
+ Arguments must be Lisp integers, and DENOMINATOR must be nonzero. */
+static double
+frac_to_double (Lisp_Object numerator, Lisp_Object denominator)
+{
+ intmax_t intmax_numerator;
+ if (FASTER_TIMEFNS && EQ (denominator, make_fixnum (1))
+ && integer_to_intmax (numerator, &intmax_numerator))
+ return intmax_numerator;
+
+ verify (FLT_RADIX == 2 || FLT_RADIX == 16);
+ enum { LOG2_FLT_RADIX = FLT_RADIX == 2 ? 1 : 4 };
+ mpz_t const *n = bignum_integer (&mpz[0], numerator);
+ mpz_t const *d = bignum_integer (&mpz[1], denominator);
+ ptrdiff_t nbits = mpz_sizeinbase (*n, 2);
+ ptrdiff_t dbits = mpz_sizeinbase (*d, 2);
+ eassume (0 < nbits);
+ eassume (0 < dbits);
+ ptrdiff_t ndig = (nbits + LOG2_FLT_RADIX - 1) / LOG2_FLT_RADIX;
+ ptrdiff_t ddig = (dbits + LOG2_FLT_RADIX - 1) / LOG2_FLT_RADIX;
+
+ /* Scale with SCALE when doing integer division. That is, compute
+ (N * FLT_RADIX**SCALE) / D [or, if SCALE is negative, N / (D *
+ FLT_RADIX**-SCALE)] as a bignum, convert the bignum to double,
+ then divide the double by FLT_RADIX**SCALE. */
+ ptrdiff_t scale = ddig - ndig + DBL_MANT_DIG + 1;
+ if (scale < 0)
+ {
+ mpz_mul_2exp (mpz[1], *d, - (scale * LOG2_FLT_RADIX));
+ d = &mpz[1];
+ }
+ else
+ {
+ /* min so we don't scale tiny numbers as if they were normalized. */
+ scale = min (scale, flt_radix_power_size - 1);
+
+ mpz_mul_2exp (mpz[0], *n, scale * LOG2_FLT_RADIX);
+ n = &mpz[0];
+ }
+
+ mpz_t *q = &mpz[2];
+ mpz_t *r = &mpz[3];
+ mpz_tdiv_qr (*q, *r, *n, *d);
+
+ /* The amount to add to the absolute value of *Q so that truncating
+ it to double will round correctly. */
+ int incr;
+
+ /* Round the quotient before converting it to double.
+ If the quotient is less than FLT_RADIX ** DBL_MANT_DIG,
+ round to the nearest integer; otherwise, it is less than
+ FLT_RADIX ** (DBL_MANT_DIG + 1) and round it to the nearest
+ multiple of FLT_RADIX. Break ties to even. */
+ if (mpz_sizeinbase (*q, 2) < DBL_MANT_DIG * LOG2_FLT_RADIX)
+ {
+ /* Converting to double will use the whole quotient so add 1 to
+ its absolute value as per round-to-even; i.e., if the doubled
+ remainder exceeds the denominator, or exactly equals the
+ denominator and adding 1 would make the quotient even. */
+ mpz_mul_2exp (*r, *r, 1);
+ int cmp = mpz_cmpabs (*r, *d);
+ incr = cmp > 0 || (cmp == 0 && (FASTER_TIMEFNS && FLT_RADIX == 2
+ ? mpz_odd_p (*q)
+ : mpz_tdiv_ui (*q, FLT_RADIX) & 1));
+ }
+ else
+ {
+ /* Converting to double will discard the quotient's low-order digit,
+ so add FLT_RADIX to its absolute value as per round-to-even. */
+ int lo_2digits = mpz_tdiv_ui (*q, FLT_RADIX * FLT_RADIX);
+ eassume (0 <= lo_2digits && lo_2digits < FLT_RADIX * FLT_RADIX);
+ int lo_digit = lo_2digits % FLT_RADIX;
+ incr = ((lo_digit > FLT_RADIX / 2
+ || (lo_digit == FLT_RADIX / 2 && FLT_RADIX % 2 == 0
+ && ((lo_2digits / FLT_RADIX) & 1
+ || mpz_sgn (*r) != 0)))
+ ? FLT_RADIX : 0);
+ }
+
+ /* Increment the absolute value of the quotient by INCR. */
+ if (!FASTER_TIMEFNS || incr != 0)
+ (mpz_sgn (*n) < 0 ? mpz_sub_ui : mpz_add_ui) (*q, *q, incr);
+
+ return scalbn (mpz_get_d (*q), -scale);
+}
+
+/* From a valid timestamp (TICKS . HZ), generate the corresponding
+ time values.
+
+ If RESULT is not null, store into *RESULT the converted time.
+ Otherwise, store into *DRESULT the number of seconds since the
+ start of the POSIX Epoch.
+
+ Return zero, which indicates success. */
+static int
+decode_ticks_hz (Lisp_Object ticks, Lisp_Object hz,
+ struct lisp_time *result, double *dresult)
+{
+ if (result)
+ {
+ result->ticks = ticks;
+ result->hz = hz;
+ }
+ else
+ *dresult = frac_to_double (ticks, hz);
+ return 0;
+}
+
+/* Lisp timestamp classification. */
+enum timeform
+ {
+ TIMEFORM_INVALID = 0,
+ TIMEFORM_HI_LO, /* seconds in the form (HI << LO_TIME_BITS) + LO. */
+ TIMEFORM_HI_LO_US, /* seconds plus microseconds (HI LO US) */
+ TIMEFORM_NIL, /* current time in nanoseconds */
+ TIMEFORM_HI_LO_US_PS, /* seconds plus micro and picoseconds (HI LO US PS) */
+ TIMEFORM_FLOAT, /* time as a float */
+ TIMEFORM_TICKS_HZ /* fractional time: HI is ticks, LO is ticks per second */
+ };
+
+/* From the valid form FORM and the time components HIGH, LOW, USEC
+ and PSEC, generate the corresponding time value. If LOW is
+ floating point, the other components should be zero and FORM should
+ not be TIMEFORM_TICKS_HZ.
+
+ If RESULT is not null, store into *RESULT the converted time.
+ Otherwise, store into *DRESULT the number of seconds since the
+ start of the POSIX Epoch. Unsuccessful calls may or may not store
+ results.
+
+ Return zero if successful, an error number otherwise. */
+static int
+decode_time_components (enum timeform form,
+ Lisp_Object high, Lisp_Object low,
+ Lisp_Object usec, Lisp_Object psec,
+ struct lisp_time *result, double *dresult)
+{
+ switch (form)
+ {
+ case TIMEFORM_INVALID:
+ return EINVAL;
+
+ case TIMEFORM_TICKS_HZ:
+ if (INTEGERP (high)
+ && (!NILP (Fnatnump (low)) && !EQ (low, make_fixnum (0))))
+ return decode_ticks_hz (high, low, result, dresult);
+ return EINVAL;
+
+ case TIMEFORM_FLOAT:
+ {
+ double t = XFLOAT_DATA (low);
+ if (result)
+ return decode_float_time (t, result);
+ else
+ {
+ *dresult = t;
+ return 0;
+ }
+ }
+
+ case TIMEFORM_NIL:
+ return decode_ticks_hz (timespec_ticks (current_timespec ()),
+ timespec_hz, result, dresult);
+
+ default:
+ break;
+ }
+
+ if (! (INTEGERP (high) && INTEGERP (low)
+ && FIXNUMP (usec) && FIXNUMP (psec)))
+ return EINVAL;
+ EMACS_INT us = XFIXNUM (usec);
+ EMACS_INT 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);
+ mpz_set_intmax (mpz[0], us / 1000000 - (us % 1000000 < 0));
+ mpz_add (mpz[0], mpz[0], *bignum_integer (&mpz[1], low));
+ mpz_addmul_ui (mpz[0], *bignum_integer (&mpz[1], high), 1 << LO_TIME_BITS);
+ ps = ps % 1000000 + 1000000 * (ps % 1000000 < 0);
+ us = us % 1000000 + 1000000 * (us % 1000000 < 0);
+
+ if (result)
+ {
+ switch (form)
+ {
+ case TIMEFORM_HI_LO:
+ /* Floats and nil were handled above, so it was an integer. */
+ result->hz = make_fixnum (1);
+ break;
+
+ case TIMEFORM_HI_LO_US:
+ mpz_mul_ui (mpz[0], mpz[0], 1000000);
+ mpz_add_ui (mpz[0], mpz[0], us);
+ result->hz = make_fixnum (1000000);
+ break;
+
+ case TIMEFORM_HI_LO_US_PS:
+ mpz_mul_ui (mpz[0], mpz[0], 1000000);
+ mpz_add_ui (mpz[0], mpz[0], us);
+ mpz_mul_ui (mpz[0], mpz[0], 1000000);
+ mpz_add_ui (mpz[0], mpz[0], ps);
+ result->hz = trillion;
+ break;
+
+ default:
+ eassume (false);
+ }
+ result->ticks = make_integer_mpz ();
+ }
+ else
+ *dresult = mpz_get_d (mpz[0]) + (us * 1e6L + ps) / 1e12L;
+
+ return 0;
+}
+
+enum { DECODE_SECS_ONLY = WARN_OBSOLETE_TIMESTAMPS + 1 };
+
+/* Decode a Lisp timestamp SPECIFIED_TIME that represents a time.
+
+ FLAGS specifies conversion flags. If FLAGS & DECODE_SECS_ONLY,
+ ignore and do not validate any sub-second components of an
+ old-format SPECIFIED_TIME. If FLAGS & WARN_OBSOLETE_TIMESTAMPS,
+ diagnose what could be obsolete (HIGH . LOW) timestamps.
+
+ If RESULT is not null, store into *RESULT the converted time;
+ otherwise, store into *DRESULT the number of seconds since the
+ start of the POSIX Epoch. Unsuccessful calls may or may not store
+ results.
+
+ Return the form of SPECIFIED-TIME. Signal an error if unsuccessful. */
+static enum timeform
+decode_lisp_time (Lisp_Object specified_time, int flags,
+ struct lisp_time *result, double *dresult)
+{
+ Lisp_Object high = make_fixnum (0);
+ Lisp_Object low = specified_time;
+ Lisp_Object usec = make_fixnum (0);
+ Lisp_Object psec = make_fixnum (0);
+ enum timeform form = TIMEFORM_HI_LO;
+
+ if (NILP (specified_time))
+ form = TIMEFORM_NIL;
+ else if (FLOATP (specified_time))
+ form = TIMEFORM_FLOAT;
+ else 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 (! (flags & DECODE_SECS_ONLY))
+ {
+ if (CONSP (low_tail))
+ {
+ usec = XCAR (low_tail);
+ low_tail = XCDR (low_tail);
+ if (CONSP (low_tail))
+ {
+ psec = XCAR (low_tail);
+ form = TIMEFORM_HI_LO_US_PS;
+ }
+ else
+ form = TIMEFORM_HI_LO_US;
+ }
+ else if (!NILP (low_tail))
+ {
+ usec = low_tail;
+ form = TIMEFORM_HI_LO_US;
+ }
+ }
+ }
+ else
+ {
+ if (flags & WARN_OBSOLETE_TIMESTAMPS
+ && RANGED_FIXNUMP (0, low, (1 << LO_TIME_BITS) - 1))
+ message ("obsolete timestamp with cdr %"pI"d", XFIXNUM (low));
+ form = TIMEFORM_TICKS_HZ;
+ }
+
+ /* Require LOW to be an integer, as otherwise the computation
+ would be considerably trickier. */
+ if (! INTEGERP (low))
+ form = TIMEFORM_INVALID;
+ }
+
+ int err = decode_time_components (form, high, low, usec, psec,
+ result, dresult);
+ if (err)
+ time_error (err);
+ return form;
+}
+
+/* Convert Z to time_t, returning true if it fits. */
+static bool
+mpz_time (mpz_t const z, time_t *t)
+{
+ if (TYPE_SIGNED (time_t))
+ {
+ intmax_t i;
+ if (! (mpz_to_intmax (z, &i) && TIME_T_MIN <= i && i <= TIME_T_MAX))
+ return false;
+ *t = i;
+ }
+ else
+ {
+ uintmax_t i;
+ if (! (mpz_to_uintmax (z, &i) && i <= TIME_T_MAX))
+ return false;
+ *t = i;
+ }
+ return true;
+}
+
+/* Convert T to struct timespec, returning an invalid timespec
+ if T does not fit. */
+static struct timespec
+lisp_to_timespec (struct lisp_time t)
+{
+ struct timespec result = invalid_timespec ();
+ int ns;
+ mpz_t *q = &mpz[0];
+ mpz_t const *qt = q;
+
+ if (FASTER_TIMEFNS && EQ (t.hz, timespec_hz))
+ {
+ if (FIXNUMP (t.ticks))
+ {
+ EMACS_INT s = XFIXNUM (t.ticks) / TIMESPEC_HZ;
+ ns = XFIXNUM (t.ticks) % TIMESPEC_HZ;
+ if (ns < 0)
+ s--, ns += TIMESPEC_HZ;
+ if ((TYPE_SIGNED (time_t) ? TIME_T_MIN <= s : 0 <= s)
+ && s <= TIME_T_MAX)
+ {
+ result.tv_sec = s;
+ result.tv_nsec = ns;
+ }
+ return result;
+ }
+ else
+ ns = mpz_fdiv_q_ui (*q, *xbignum_val (t.ticks), TIMESPEC_HZ);
+ }
+ else if (FASTER_TIMEFNS && EQ (t.hz, make_fixnum (1)))
+ {
+ ns = 0;
+ if (FIXNUMP (t.ticks))
+ {
+ EMACS_INT s = XFIXNUM (t.ticks);
+ if ((TYPE_SIGNED (time_t) ? TIME_T_MIN <= s : 0 <= s)
+ && s <= TIME_T_MAX)
+ {
+ result.tv_sec = s;
+ result.tv_nsec = ns;
+ }
+ return result;
+ }
+ else
+ qt = xbignum_val (t.ticks);
+ }
+ else
+ {
+ mpz_mul_ui (*q, *bignum_integer (q, t.ticks), TIMESPEC_HZ);
+ mpz_fdiv_q (*q, *q, *bignum_integer (&mpz[1], t.hz));
+ ns = mpz_fdiv_q_ui (*q, *q, TIMESPEC_HZ);
+ }
+
+ /* With some versions of MinGW, tv_sec is a 64-bit type, whereas
+ time_t is a 32-bit type. */
+ time_t sec;
+ if (mpz_time (*qt, &sec))
+ {
+ result.tv_sec = sec;
+ result.tv_nsec = ns;
+ }
+ return result;
+}
+
+/* Convert (HIGH LOW USEC PSEC) to struct timespec.
+ Return true if successful. */
+bool
+list4_to_timespec (Lisp_Object high, Lisp_Object low,
+ Lisp_Object usec, Lisp_Object psec,
+ struct timespec *result)
+{
+ struct lisp_time t;
+ if (decode_time_components (TIMEFORM_HI_LO_US_PS, high, low, usec, psec,
+ &t, 0))
+ return false;
+ *result = lisp_to_timespec (t);
+ return timespec_valid_p (*result);
+}
+
+/* Decode a Lisp list SPECIFIED_TIME that represents a time.
+ If SPECIFIED_TIME is nil, use the current time.
+ Signal an error if SPECIFIED_TIME does not represent a time.
+ If PFORM, store the time's form into *PFORM. */
+static struct lisp_time
+lisp_time_struct (Lisp_Object specified_time, enum timeform *pform)
+{
+ struct lisp_time t;
+ enum timeform form
+ = decode_lisp_time (specified_time, WARN_OBSOLETE_TIMESTAMPS, &t, 0);
+ if (pform)
+ *pform = form;
+ return t;
+}
+
+/* Decode a Lisp list SPECIFIED_TIME that represents a time.
+ Discard any low-order (sub-ns) resolution.
+ If SPECIFIED_TIME is nil, use the current time.
+ Signal an error if SPECIFIED_TIME does not represent a timespec. */
+struct timespec
+lisp_time_argument (Lisp_Object specified_time)
+{
+ struct lisp_time lt = lisp_time_struct (specified_time, 0);
+ 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)
+{
+ int flags = WARN_OBSOLETE_TIMESTAMPS | DECODE_SECS_ONLY;
+ struct lisp_time lt;
+ decode_lisp_time (specified_time, flags, &lt, 0);
+ struct timespec t = lisp_to_timespec (lt);
+ if (! timespec_valid_p (t))
+ time_overflow ();
+ return t.tv_sec;
+}
+
+/* Return the sum of the Lisp integers A and B.
+ Subtract instead of adding if SUBTRACT.
+ This function is tuned for small B. */
+static Lisp_Object
+lispint_arith (Lisp_Object a, Lisp_Object b, bool subtract)
+{
+ bool mpz_done = false;
+
+ if (FASTER_TIMEFNS && FIXNUMP (b))
+ {
+ if (EQ (b, make_fixnum (0)))
+ return a;
+ if (FIXNUMP (a))
+ return make_int (subtract
+ ? XFIXNUM (a) - XFIXNUM (b)
+ : XFIXNUM (a) + XFIXNUM (b));
+ if (eabs (XFIXNUM (b)) <= ULONG_MAX)
+ {
+ ((XFIXNUM (b) < 0) == subtract ? mpz_add_ui : mpz_sub_ui)
+ (mpz[0], *xbignum_val (a), eabs (XFIXNUM (b)));
+ mpz_done = true;
+ }
+ }
+
+ if (!mpz_done)
+ (subtract ? mpz_sub : mpz_add) (mpz[0],
+ *bignum_integer (&mpz[0], a),
+ *bignum_integer (&mpz[1], b));
+ return make_integer_mpz ();
+}
+
+/* Given Lisp operands A and B, add their values, and return the
+ result as a Lisp timestamp that is in (TICKS . HZ) form if either A
+ or B are in that form or are floats, (HI LO US PS) form otherwise.
+ Subtract instead of adding if SUBTRACT. */
+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);
+ }
+ enum timeform aform, bform;
+ struct lisp_time ta = lisp_time_struct (a, &aform);
+
+ if (FLOATP (b) && !isfinite (XFLOAT_DATA (b)))
+ return subtract ? make_float (-XFLOAT_DATA (b)) : b;
+
+ /* Subtract nil from nil correctly, and handle other eq values
+ quicker while we're at it. Compare here rather than earlier, to
+ handle NaNs and check formats. */
+ struct lisp_time tb;
+ if (EQ (a, b))
+ bform = aform, tb = ta;
+ else
+ tb = lisp_time_struct (b, &bform);
+
+ Lisp_Object ticks, hz;
+
+ if (FASTER_TIMEFNS && EQ (ta.hz, tb.hz))
+ {
+ hz = ta.hz;
+ ticks = lispint_arith (ta.ticks, tb.ticks, subtract);
+ }
+ else
+ {
+ /* The plan is to decompose ta into na/da and tb into nb/db.
+ Start by computing da and db, their minimum (which will be
+ needed later) and the iticks temporary that will become
+ available once only their minimum is needed. */
+ mpz_t const *da = bignum_integer (&mpz[1], ta.hz);
+ mpz_t const *db = bignum_integer (&mpz[2], tb.hz);
+ bool da_lt_db = mpz_cmp (*da, *db) < 0;
+ mpz_t const *hzmin = da_lt_db ? da : db;
+ mpz_t *iticks = &mpz[da_lt_db + 1];
+
+ /* The plan is to compute (na * (db/g) + nb * (da/g)) / lcm (da, db)
+ where g = gcd (da, db). Start by computing g. */
+ mpz_t *g = &mpz[3];
+ mpz_gcd (*g, *da, *db);
+
+ /* fa = da/g, fb = db/g. */
+ mpz_t *fa = &mpz[4], *fb = &mpz[3];
+ mpz_tdiv_q (*fa, *da, *g);
+ mpz_tdiv_q (*fb, *db, *g);
+
+ /* ihz = fa * db. This is equal to lcm (da, db). */
+ mpz_t *ihz = &mpz[0];
+ mpz_mul (*ihz, *fa, *db);
+
+ /* When warning about obsolete timestamps, if the smaller
+ denominator comes from a non-(TICKS . HZ) timestamp and could
+ generate a (TICKS . HZ) timestamp that would look obsolete,
+ arrange for the result to have a higher HZ to avoid a
+ spurious warning by a later consumer of this function's
+ returned value. */
+ verify (1 << LO_TIME_BITS <= ULONG_MAX);
+ if (WARN_OBSOLETE_TIMESTAMPS
+ && (da_lt_db ? aform : bform) == TIMEFORM_FLOAT
+ && (da_lt_db ? bform : aform) != TIMEFORM_TICKS_HZ
+ && mpz_cmp_ui (*hzmin, 1) > 0
+ && mpz_cmp_ui (*hzmin, 1 << LO_TIME_BITS) < 0)
+ {
+ mpz_t *hzmin1 = &mpz[2 - da_lt_db];
+ mpz_set_ui (*hzmin1, 1 << LO_TIME_BITS);
+ hzmin = hzmin1;
+ }
+
+ /* iticks = (fb * na) OP (fa * nb), where OP is + or -. */
+ mpz_t const *na = bignum_integer (iticks, ta.ticks);
+ mpz_mul (*iticks, *fb, *na);
+ mpz_t const *nb = bignum_integer (&mpz[3], tb.ticks);
+ (subtract ? mpz_submul : mpz_addmul) (*iticks, *fa, *nb);
+
+ /* Normalize iticks/ihz by dividing both numerator and
+ denominator by ig = gcd (iticks, ihz). However, if that
+ would cause the denominator to become less than hzmin,
+ rescale the denominator upwards from its ordinary value by
+ multiplying numerator and denominator so that the denominator
+ becomes at least hzmin. This rescaling avoids returning a
+ timestamp that is less precise than both a and b, or a
+ timestamp that looks obsolete when that might be a problem. */
+ mpz_t *ig = &mpz[3];
+ mpz_gcd (*ig, *iticks, *ihz);
+
+ if (!FASTER_TIMEFNS || mpz_cmp_ui (*ig, 1) > 0)
+ {
+ mpz_tdiv_q (*iticks, *iticks, *ig);
+ mpz_tdiv_q (*ihz, *ihz, *ig);
+
+ if (!FASTER_TIMEFNS || mpz_cmp (*ihz, *hzmin) < 0)
+ {
+ /* Rescale straightforwardly. Although this might not
+ yield the minimal denominator that preserves numeric
+ value and is at least hzmin, calculating such a
+ denominator would be too expensive because it would
+ require testing multisets of factors of lcm (da, db). */
+ mpz_t *rescale = &mpz[3];
+ mpz_cdiv_q (*rescale, *hzmin, *ihz);
+ mpz_mul (*iticks, *iticks, *rescale);
+ mpz_mul (*ihz, *ihz, *rescale);
+ }
+ }
+ hz = make_integer_mpz ();
+ mpz_swap (mpz[0], *iticks);
+ ticks = make_integer_mpz ();
+ }
+
+ /* Return an integer if the timestamp resolution is 1,
+ otherwise the (TICKS . HZ) form if !CURRENT_TIME_LIST or if
+ either input used (TICKS . HZ) form or the result can't be expressed
+ exactly in (HI LO US PS) form, otherwise the (HI LO US PS) form
+ for backward compatibility. */
+ return (EQ (hz, make_fixnum (1))
+ ? ticks
+ : (!CURRENT_TIME_LIST
+ || aform == TIMEFORM_TICKS_HZ
+ || bform == TIMEFORM_TICKS_HZ
+ || !trillion_factor (hz))
+ ? Fcons (ticks, hz)
+ : ticks_hz_list4 (ticks, hz));
+}
+
+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.
+See `format-time-string' for the various forms of a time value.
+For example, nil stands for the current time. */)
+ (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.
+You can use `float-time' to convert the difference into elapsed seconds.
+See `format-time-string' for the various forms of a time value.
+For example, nil stands for the current time. */)
+ (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;
+ }
+
+ struct lisp_time ta = lisp_time_struct (a, 0);
+
+ /* Compare nil to nil correctly, and handle other eq values quicker
+ while we're at it. Compare here rather than earlier, to handle
+ NaNs and check formats. */
+ if (EQ (a, b))
+ return 0;
+
+ struct lisp_time tb = lisp_time_struct (b, 0);
+ mpz_t const *za = bignum_integer (&mpz[0], ta.ticks);
+ mpz_t const *zb = bignum_integer (&mpz[1], tb.ticks);
+ if (! (FASTER_TIMEFNS && EQ (ta.hz, tb.hz)))
+ {
+ /* This could be sped up by looking at the signs, sizes, and
+ number of bits of the two sides; see how GMP does mpq_cmp.
+ It may not be worth the trouble here, though. */
+ mpz_mul (mpz[0], *za, *bignum_integer (&mpz[2], tb.hz));
+ mpz_mul (mpz[1], *zb, *bignum_integer (&mpz[2], ta.hz));
+ za = &mpz[0];
+ zb = &mpz[1];
+ }
+ return mpz_cmp (*za, *zb);
+}
+
+DEFUN ("time-less-p", Ftime_less_p, Stime_less_p, 2, 2, 0,
+ doc: /* Return non-nil if time value A is less than time value B.
+See `format-time-string' for the various forms of a time value.
+For example, nil stands for the current time. */)
+ (Lisp_Object a, Lisp_Object b)
+{
+ return time_cmp (a, b) < 0 ? Qt : Qnil;
+}
+
+DEFUN ("time-equal-p", Ftime_equal_p, Stime_equal_p, 2, 2, 0,
+ doc: /* Return non-nil if A and B are equal time values.
+See `format-time-string' for the various forms of a time value. */)
+ (Lisp_Object a, Lisp_Object b)
+{
+ return time_cmp (a, b) == 0 ? Qt : Qnil;
+}
+
+
+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 a time value to convert to float
+instead of the current time. See `format-time-string' for the various
+forms of a time value.
+
+WARNING: Since the result is floating point, it may not be exact.
+If precise time stamps are required, use either `encode-time',
+or (if you need time as a string) `format-time-string'. */)
+ (Lisp_Object specified_time)
+{
+ double t;
+ decode_lisp_time (specified_time, 0, 0, &t);
+ 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 NUL
+ 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 NUL-terminated strings in the format
+ argument. Normally there's just one NUL-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)
+ {
+ int localtime_errno = errno;
+ xtzfree (tz);
+ time_error (localtime_errno);
+ }
+ 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 value TIME.
+A time value that is omitted or nil stands for the current time,
+a number stands for that many seconds, an integer pair (TICKS . HZ)
+stands for TICKS/HZ seconds, and an integer list (HI LO US PS) stands
+for HI*2**16 + LO + US/10**6 + PS/10**12 seconds. This function
+treats seconds as time since the epoch of 1970-01-01 00:00:00 UTC.
+
+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 "%+4Y-%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.
+
+A %-sequence can contain optional flags, field width, and a modifier
+(in that order) after the `%'. The flags are:
+
+`-' Do not pad the field.
+`_' Pad with spaces.
+`0' Pad with zeros.
+`+' Pad with zeros and put `+' before nonnegative year numbers with >4 digits.
+`^' Use upper case characters if possible.
+`#' Use opposite case characters if possible.
+
+A field width N is an unsigned decimal integer with a leading digit nonzero.
+%NX is like %X, but takes up at least N positions.
+
+The modifiers are:
+
+`E' Use the locale's alternative version.
+`O' Use 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, 3, 0,
+ doc: /* Decode a time value as (SEC MINUTE HOUR DAY MONTH YEAR DOW DST UTCOFF).
+The optional TIME is the time value to convert. See
+`format-time-string' for the various forms of a time value.
+
+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 optional FORM specifies the form of the SEC member. If `integer',
+SEC is an integer; if t, SEC uses the same resolution as TIME. An
+omitted or nil FORM is currently treated like `integer', but this may
+change in future Emacs versions.
+
+To access (or alter) the elements in the time value, the
+`decoded-time-second', `decoded-time-minute', `decoded-time-hour',
+`decoded-time-day', `decoded-time-month', `decoded-time-year',
+`decoded-time-weekday', `decoded-time-dst' and `decoded-time-zone'
+accessors can be used.
+
+The list has the following nine members: SEC is an integer or
+Lisp timestamp representing a nonnegative value less than 60
+\(or less than 61 if the operating system supports leap seconds).
+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, and its
+SEC is always an integer between 0 and 59.)
+
+usage: (decode-time &optional TIME ZONE FORM) */)
+ (Lisp_Object specified_time, Lisp_Object zone, Lisp_Object form)
+{
+ struct lisp_time lt = lisp_time_struct (specified_time, 0);
+ struct timespec ts = lisp_to_timespec (lt);
+ if (! timespec_valid_p (ts))
+ time_overflow ();
+ time_t time_spec = ts.tv_sec;
+ struct tm local_tm, gmt_tm;
+ timezone_t tz = tzlookup (zone, false);
+ struct tm *tm = emacs_localtime_rz (tz, &time_spec, &local_tm);
+ int localtime_errno = errno;
+ xtzfree (tz);
+
+ if (!tm)
+ time_error (localtime_errno);
+
+ Lisp_Object year;
+ if (FASTER_TIMEFNS
+ && MOST_NEGATIVE_FIXNUM - TM_YEAR_BASE <= local_tm.tm_year
+ && local_tm.tm_year <= MOST_POSITIVE_FIXNUM - TM_YEAR_BASE)
+ {
+ /* Avoid overflow when INT_MAX - TM_YEAR_BASE < local_tm.tm_year. */
+ EMACS_INT tm_year_base = TM_YEAR_BASE;
+ year = make_fixnum (local_tm.tm_year + tm_year_base);
+ }
+ else
+ {
+ mpz_set_si (mpz[0], local_tm.tm_year);
+ mpz_add_ui (mpz[0], mpz[0], TM_YEAR_BASE);
+ year = make_integer_mpz ();
+ }
+
+ Lisp_Object hz = lt.hz, sec;
+ if (EQ (hz, make_fixnum (1)) || !EQ (form, Qt))
+ sec = make_fixnum (local_tm.tm_sec);
+ else
+ {
+ Lisp_Object ticks; /* hz * tm_sec + mod (lt.ticks, hz) */
+ intmax_t n;
+ if (FASTER_TIMEFNS && FIXNUMP (lt.ticks) && FIXNUMP (hz)
+ && !INT_MULTIPLY_WRAPV (XFIXNUM (hz), local_tm.tm_sec, &n)
+ && ! (INT_ADD_WRAPV
+ (n, (XFIXNUM (lt.ticks) % XFIXNUM (hz)
+ + (XFIXNUM (lt.ticks) % XFIXNUM (hz) < 0
+ ? XFIXNUM (hz) : 0)),
+ &n)))
+ ticks = make_int (n);
+ else
+ {
+ mpz_fdiv_r (mpz[0],
+ *bignum_integer (&mpz[0], lt.ticks),
+ *bignum_integer (&mpz[1], hz));
+ mpz_addmul_ui (mpz[0], *bignum_integer (&mpz[1], hz),
+ local_tm.tm_sec);
+ ticks = make_integer_mpz ();
+ }
+ sec = Fcons (ticks, hz);
+ }
+
+ return CALLN (Flist,
+ 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),
+ year,
+ 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 integer and that
+ the result is representable as an int. 0 <= OFFSET <= TM_YEAR_BASE. */
+static int
+check_tm_member (Lisp_Object obj, int offset)
+{
+ if (FASTER_TIMEFNS && INT_MAX <= MOST_POSITIVE_FIXNUM - TM_YEAR_BASE)
+ {
+ CHECK_FIXNUM (obj);
+ EMACS_INT n = XFIXNUM (obj);
+ int i;
+ if (INT_SUBTRACT_WRAPV (n, offset, &i))
+ time_overflow ();
+ return i;
+ }
+ else
+ {
+ CHECK_INTEGER (obj);
+ mpz_sub_ui (mpz[0], *bignum_integer (&mpz[0], obj), offset);
+ intmax_t i;
+ if (! (mpz_to_intmax (mpz[0], &i) && INT_MIN <= i && i <= INT_MAX))
+ time_overflow ();
+ return i;
+ }
+}
+
+DEFUN ("encode-time", Fencode_time, Sencode_time, 1, MANY, 0,
+ doc: /* Convert TIME to a timestamp.
+
+TIME is a list (SECOND MINUTE HOUR DAY MONTH YEAR IGNORED DST ZONE).
+in the style of `decode-time', so that (encode-time (decode-time ...)) works.
+In this list, ZONE can be 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. If ZONE specifies a
+time zone with daylight-saving transitions, DST is t for daylight
+saving time, nil for standard time, and -1 to cause the daylight
+saving flag to be guessed.
+
+As an obsolescent calling convention, if this function is called with
+6 or more arguments, the first 6 arguments are SECOND, MINUTE, HOUR,
+DAY, MONTH, and YEAR, and specify the components of a decoded time,
+where DST assumed to be -1 and FORM is omitted. If there are more
+than 6 arguments the *last* argument is used as ZONE and any other
+extra arguments are ignored, so that (apply #\\='encode-time
+(decode-time ...)) works. In this obsolescent convention, DST and
+ZONE default to -1 and nil respectively.
+
+Years before 1970 are not guaranteed to work. On some systems,
+year values as low as 1901 do work.
+
+usage: (encode-time TIME &rest OBSOLESCENT-ARGUMENTS) */)
+ (ptrdiff_t nargs, Lisp_Object *args)
+{
+ struct tm tm;
+ Lisp_Object zone = Qnil;
+ Lisp_Object a = args[0];
+ Lisp_Object secarg, minarg, hourarg, mdayarg, monarg, yeararg;
+ tm.tm_isdst = -1;
+
+ if (nargs == 1)
+ {
+ Lisp_Object tail = a;
+ for (int i = 0; i < 9; i++, tail = XCDR (tail))
+ CHECK_CONS (tail);
+ secarg = XCAR (a); a = XCDR (a);
+ minarg = XCAR (a); a = XCDR (a);
+ hourarg = XCAR (a); a = XCDR (a);
+ mdayarg = XCAR (a); a = XCDR (a);
+ monarg = XCAR (a); a = XCDR (a);
+ yeararg = XCAR (a); a = XCDR (a);
+ a = XCDR (a);
+ Lisp_Object dstflag = XCAR (a); a = XCDR (a);
+ zone = XCAR (a);
+ if (SYMBOLP (dstflag) && !FIXNUMP (zone) && !CONSP (zone))
+ tm.tm_isdst = !NILP (dstflag);
+ }
+ else if (nargs < 6)
+ xsignal2 (Qwrong_number_of_arguments, Qencode_time, make_fixnum (nargs));
+ else
+ {
+ if (6 < nargs)
+ zone = args[nargs - 1];
+ secarg = a;
+ minarg = args[1];
+ hourarg = args[2];
+ mdayarg = args[3];
+ monarg = args[4];
+ yeararg = args[5];
+ }
+
+ struct lisp_time lt;
+ decode_lisp_time (secarg, 0, &lt, 0);
+ Lisp_Object hz = lt.hz, sec, subsecticks;
+ if (FASTER_TIMEFNS && EQ (hz, make_fixnum (1)))
+ {
+ sec = lt.ticks;
+ subsecticks = make_fixnum (0);
+ }
+ else
+ {
+ mpz_fdiv_qr (mpz[0], mpz[1],
+ *bignum_integer (&mpz[0], lt.ticks),
+ *bignum_integer (&mpz[1], hz));
+ sec = make_integer_mpz ();
+ mpz_swap (mpz[0], mpz[1]);
+ subsecticks = make_integer_mpz ();
+ }
+ tm.tm_sec = check_tm_member (sec, 0);
+ tm.tm_min = check_tm_member (minarg, 0);
+ tm.tm_hour = check_tm_member (hourarg, 0);
+ tm.tm_mday = check_tm_member (mdayarg, 0);
+ tm.tm_mon = check_tm_member (monarg, 1);
+ tm.tm_year = check_tm_member (yeararg, TM_YEAR_BASE);
+
+ timezone_t tz = tzlookup (zone, false);
+ tm.tm_wday = -1;
+ time_t value = mktime_z (tz, &tm);
+ int mktime_errno = errno;
+ xtzfree (tz);
+
+ if (tm.tm_wday < 0)
+ time_error (mktime_errno);
+
+ if (EQ (hz, make_fixnum (1)))
+ return (CURRENT_TIME_LIST
+ ? list2 (hi_time (value), lo_time (value))
+ : INT_TO_INTEGER (value));
+ else
+ {
+ struct lisp_time val1 = { INT_TO_INTEGER (value), make_fixnum (1) };
+ Lisp_Object secticks = lisp_time_hz_ticks (val1, hz);
+ Lisp_Object ticks = lispint_arith (secticks, subsecticks, false);
+ return Fcons (ticks, hz);
+ }
+}
+
+DEFUN ("time-convert", Ftime_convert, Stime_convert, 1, 2, 0,
+ doc: /* Convert TIME value to a Lisp timestamp.
+With optional FORM, convert to that timestamp form.
+Truncate the returned value toward minus infinity.
+
+If FORM is nil (the default), return the the same form as `current-time'.
+If FORM is a positive integer, return a pair of integers (TICKS . FORM),
+where TICKS is the number of clock ticks and FORM is the clock frequency
+in ticks per second. (Currently the positive integer should be at least
+65536 if the returned value is expected to be given to standard functions
+expecting Lisp timestamps.) If FORM is t, return (TICKS . PHZ), where
+PHZ is a suitable clock frequency in ticks per second. If FORM is
+`integer', return an integer count of seconds. If FORM is `list',
+return an integer list (HIGH LOW USEC PSEC), where HIGH has the most
+significant bits of the seconds, LOW has the least significant 16
+bits, and USEC and PSEC are the microsecond and picosecond counts. */)
+ (Lisp_Object time, Lisp_Object form)
+{
+ struct lisp_time t;
+ enum timeform input_form = decode_lisp_time (time, 0, &t, 0);
+ if (NILP (form))
+ form = CURRENT_TIME_LIST ? Qlist : Qt;
+ if (EQ (form, Qlist))
+ return ticks_hz_list4 (t.ticks, t.hz);
+ if (EQ (form, Qinteger))
+ return FASTER_TIMEFNS && INTEGERP (time) ? time : lisp_time_seconds (t);
+ if (EQ (form, Qt))
+ form = t.hz;
+ if (FASTER_TIMEFNS
+ && input_form == TIMEFORM_TICKS_HZ && EQ (form, XCDR (time)))
+ return time;
+ return Fcons (lisp_time_hz_ticks (t, form), form);
+}
+
+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.
+
+In a future Emacs version, the format of the returned timestamp is
+planned to change. Use `time-convert' if you need a particular
+timestamp form; for example, (time-convert nil \\='integer) returns
+the current time in seconds. */)
+ (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 the time value to format instead of
+the current time. See `format-time-string' for the various forms of a
+time value.
+
+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);
+ int localtime_errno = errno;
+ xtzfree (tz);
+ if (! tmp)
+ time_error (localtime_errno);
+
+ 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" };
+ intmax_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 %"PRIdMAX,
+ 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 be a Lisp
+time value; see `format-time-string' for the various forms of a time
+value.
+
+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;
+}
+
+#if (ULONG_MAX < TRILLION || !FASTER_TIMEFNS) && !defined ztrillion
+# define NEED_ZTRILLION_INIT 1
+#endif
+
+#ifdef NEED_ZTRILLION_INIT
+static void
+syms_of_timefns_for_pdumper (void)
+{
+ mpz_init_set_ui (ztrillion, 1000000);
+ mpz_mul_ui (ztrillion, ztrillion, 1000000);
+}
+#endif
+
+void
+syms_of_timefns (void)
+{
+#ifndef timespec_hz
+ timespec_hz = make_int (TIMESPEC_HZ);
+ staticpro (&timespec_hz);
+#endif
+#ifndef trillion
+ trillion = make_int (1000000000000);
+ staticpro (&trillion);
+#endif
+
+ DEFSYM (Qencode_time, "encode-time");
+
+ defsubr (&Scurrent_time);
+ defsubr (&Stime_convert);
+ 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);
+
+ flt_radix_power = make_vector (flt_radix_power_size, Qnil);
+ staticpro (&flt_radix_power);
+
+#ifdef NEED_ZTRILLION_INIT
+ pdumper_do_now_and_after_load (syms_of_timefns_for_pdumper);
+#endif
+}