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New time and date code from ADO

This commit is contained in:
jtc 1995-03-09 23:21:48 +00:00
parent 997428654a
commit 1fac1c1776
7 changed files with 2369 additions and 0 deletions
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56
lib/libc/time/asctime.c Normal file
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#ifndef lint
#ifndef NOID
static char elsieid[] = "@(#)asctime.c 7.6";
#endif /* !defined NOID */
#endif /* !defined lint */
/*LINTLIBRARY*/
#include "private.h"
#include "tzfile.h"
/*
** A la X3J11, with core dump avoidance.
*/
char *
asctime(timeptr)
register const struct tm * timeptr;
{
static const char wday_name[][3] = {
"Sun", "Mon", "Tue", "Wed", "Thu", "Fri", "Sat"
};
static const char mon_name[][3] = {
"Jan", "Feb", "Mar", "Apr", "May", "Jun",
"Jul", "Aug", "Sep", "Oct", "Nov", "Dec"
};
/*
** Big enough for something such as
** ??? ???-2147483648 -2147483648:-2147483648:-2147483648 -2147483648\n
** (two three-character abbreviations, five strings denoting integers,
** three explicit spaces, two explicit colons, a newline,
** and a trailing ASCII nul).
*/
static char result[3 * 2 + 5 * INT_STRLEN_MAXIMUM(int) +
3 + 2 + 1 + 1];
register const char * wn;
register const char * mn;
if (timeptr->tm_wday < 0 || timeptr->tm_wday >= DAYSPERWEEK)
wn = "???";
else wn = wday_name[timeptr->tm_wday];
if (timeptr->tm_mon < 0 || timeptr->tm_mon >= MONSPERYEAR)
mn = "???";
else mn = mon_name[timeptr->tm_mon];
/*
** The X3J11-suggested format is
** "%.3s %.3s%3d %02.2d:%02.2d:%02.2d %d\n"
** Since the .2 in 02.2d is ignored, we drop it.
*/
(void) sprintf(result, "%.3s %.3s%3d %02d:%02d:%02d %d\n",
wn, mn,
timeptr->tm_mday, timeptr->tm_hour,
timeptr->tm_min, timeptr->tm_sec,
TM_YEAR_BASE + timeptr->tm_year);
return result;
}

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lib/libc/time/difftime.c Normal file
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#ifndef lint
#ifndef NOID
static char elsieid[] = "@(#)difftime.c 7.5";
#endif /* !defined NOID */
#endif /* !defined lint */
/*LINTLIBRARY*/
#include "private.h"
/*
** Algorithm courtesy Paul Eggert (eggert@twinsun.com).
*/
#ifdef HAVE_LONG_DOUBLE
#define long_double long double
#endif /* defined HAVE_LONG_DOUBLE */
#ifndef HAVE_LONG_DOUBLE
#define long_double double
#endif /* !defined HAVE_LONG_DOUBLE */
double
difftime(time1, time0)
const time_t time1;
const time_t time0;
{
time_t delta;
time_t hibit;
if (sizeof(time_t) < sizeof(double))
return (double) time1 - (double) time0;
if (sizeof(time_t) < sizeof(long_double))
return (long_double) time1 - (long_double) time0;
if (time1 < time0)
return -difftime(time0, time1);
/*
** As much as possible, avoid loss of precision
** by computing the difference before converting to double.
*/
delta = time1 - time0;
if (delta >= 0)
return delta;
/*
** Repair delta overflow.
*/
hibit = 1;
while ((hibit <<= 1) > 0)
continue;
/*
** The following expression rounds twice, which means
** the result may not be the closest to the true answer.
** For example, suppose time_t is 64-bit signed int,
** long_double is IEEE 754 double with default rounding,
** time1 = 9223372036854775807 and time0 = -1536.
** Then the true difference is 9223372036854777343,
** which rounds to 9223372036854777856
** with a total error of 513.
** But delta overflows to -9223372036854774273,
** which rounds to -9223372036854774784, and correcting
** this by subtracting 2 * (long_double) hibit
** (i.e. by adding 2**64 = 18446744073709551616)
** yields 9223372036854776832, which
** rounds to 9223372036854775808
** with a total error of 1535 instead.
** This problem occurs only with very large differences.
** It's too painful to fix this portably.
** We are not alone in this problem;
** many C compilers round twice when converting
** large unsigned types to small floating types,
** so if time_t is unsigned the "return delta" above
** has the same double-rounding problem.
*/
return delta - 2 * (long_double) hibit;
}

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lib/libc/time/localtime.c Normal file
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194
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#ifndef PRIVATE_H
#define PRIVATE_H
/*
** This header is for use ONLY with the time conversion code.
** There is no guarantee that it will remain unchanged,
** or that it will remain at all.
** Do NOT copy it to any system include directory.
** Thank you!
*/
/*
** ID
*/
#ifndef lint
#ifndef NOID
static char privatehid[] = "@(#)private.h 7.33";
#endif /* !defined NOID */
#endif /* !defined lint */
/*
** Defaults for preprocessor symbols.
** You can override these in your C compiler options, e.g. `-DHAVE_ADJTIME=0'.
*/
#ifndef HAVE_ADJTIME
#define HAVE_ADJTIME 1
#endif /* !defined HAVE_ADJTIME */
#ifndef HAVE_SETTIMEOFDAY
#define HAVE_SETTIMEOFDAY 3
#endif /* !defined HAVE_SETTIMEOFDAY */
#ifndef HAVE_UNISTD_H
#define HAVE_UNISTD_H 1
#endif /* !defined HAVE_UNISTD_H */
#ifndef LOCALE_HOME
#define LOCALE_HOME "/usr/lib/locale"
#endif /* !defined LOCALE_HOME */
/*
** Nested includes
*/
#include "sys/types.h" /* for time_t */
#include "stdio.h"
#include "ctype.h"
#include "errno.h"
#include "string.h"
#include "limits.h" /* for CHAR_BIT */
#include "time.h"
#include "stdlib.h"
#if HAVE_UNISTD_H - 0
#include "unistd.h" /* for F_OK and R_OK */
#endif /* HAVE_UNISTD_H - 0 */
#if !(HAVE_UNISTD_H - 0)
#ifndef F_OK
#define F_OK 0
#endif /* !defined F_OK */
#ifndef R_OK
#define R_OK 4
#endif /* !defined R_OK */
#endif /* !(HAVE_UNISTD_H - 0) */
/*
** Workarounds for compilers/systems.
*/
/*
** SunOS 4.1.1 cc lacks const.
*/
#ifndef const
#ifndef __STDC__
#define const
#endif /* !defined __STDC__ */
#endif /* !defined const */
/*
** SunOS 4.1.1 cc lacks prototypes.
*/
#ifndef P
#ifdef __STDC__
#define P(x) x
#endif /* defined __STDC__ */
#ifndef __STDC__
#define P(x) ()
#endif /* !defined __STDC__ */
#endif /* !defined P */
/*
** SunOS 4.1.1 headers lack EXIT_SUCCESS.
*/
#ifndef EXIT_SUCCESS
#define EXIT_SUCCESS 0
#endif /* !defined EXIT_SUCCESS */
/*
** SunOS 4.1.1 headers lack EXIT_FAILURE.
*/
#ifndef EXIT_FAILURE
#define EXIT_FAILURE 1
#endif /* !defined EXIT_FAILURE */
/*
** SunOS 4.1.1 headers lack FILENAME_MAX.
*/
#ifndef FILENAME_MAX
#ifndef MAXPATHLEN
#ifdef unix
#include "sys/param.h"
#endif /* defined unix */
#endif /* !defined MAXPATHLEN */
#ifdef MAXPATHLEN
#define FILENAME_MAX MAXPATHLEN
#endif /* defined MAXPATHLEN */
#ifndef MAXPATHLEN
#define FILENAME_MAX 1024 /* Pure guesswork */
#endif /* !defined MAXPATHLEN */
#endif /* !defined FILENAME_MAX */
/*
** SunOS 4.1.1 libraries lack remove.
*/
#ifndef remove
extern int unlink P((const char * filename));
#define remove unlink
#endif /* !defined remove */
/*
** Finally, some convenience items.
*/
#ifndef TRUE
#define TRUE 1
#endif /* !defined TRUE */
#ifndef FALSE
#define FALSE 0
#endif /* !defined FALSE */
#ifndef INT_STRLEN_MAXIMUM
/*
** 302 / 1000 is log10(2.0) rounded up.
** Subtract one for the sign bit;
** add one for integer division truncation;
** add one more for a minus sign.
*/
#define INT_STRLEN_MAXIMUM(type) \
((sizeof(type) * CHAR_BIT - 1) * 302 / 1000 + 2)
#endif /* !defined INT_STRLEN_MAXIMUM */
/*
** INITIALIZE(x)
*/
#ifndef GNUC_or_lint
#ifdef lint
#define GNUC_or_lint
#endif /* defined lint */
#ifndef lint
#ifdef __GNUC__
#define GNUC_or_lint
#endif /* defined __GNUC__ */
#endif /* !defined lint */
#endif /* !defined GNUC_or_lint */
#ifndef INITIALIZE
#ifdef GNUC_or_lint
#define INITIALIZE(x) ((x) = 0)
#endif /* defined GNUC_or_lint */
#ifndef GNUC_or_lint
#define INITIALIZE(x)
#endif /* !defined GNUC_or_lint */
#endif /* !defined INITIALIZE */
/*
** UNIX was a registered trademark of UNIX System Laboratories in 1993.
*/
#endif /* !defined PRIVATE_H */

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.TH TIME2POSIX 3
.SH NAME
time2posix, posix2time \- convert seconds since the Epoch
.SH SYNOPSIS
.nf
.B #include <sys/types.h>
.B #include <time.h>
.PP
.B time_t time2posix(t)
.B time_t t
.PP
.B time_t posix2time(t)
.B time_t t
.PP
.B cc ... -lz
.fi
.SH DESCRIPTION
IEEE Standard 1003.1
(POSIX)
legislates that a time_t value of
536457599 shall correspond to "Wed Dec 31 23:59:59 GMT 1986."
This effectively implies that POSIX time_t's cannot include leap
seconds and,
therefore,
that the system time must be adjusted as each leap occurs.
.PP
If the time package is configured with leap-second support
enabled,
however,
no such adjustment is needed and
time_t values continue to increase over leap events
(as a true `seconds since...' value).
This means that these values will differ from those required by POSIX
by the net number of leap seconds inserted since the Epoch.
.PP
Typically this is not a problem as the type time_t is intended
to be
(mostly)
opaque\(emtime_t values should only be obtained-from and
passed-to functions such as
.IR time(2) ,
.IR localtime(3) ,
.IR mktime(3) ,
and
.IR difftime(3) .
However,
POSIX gives an arithmetic
expression for directly computing a time_t value from a given date/time,
and the same relationship is assumed by some
(usually older)
applications.
Any programs creating/dissecting time_t's
using such a relationship will typically not handle intervals
over leap seconds correctly.
.PP
The
.I time2posix
and
.I posix2time
functions are provided to address this time_t mismatch by converting
between local time_t values and their POSIX equivalents.
This is done by accounting for the number of time-base changes that
would have taken place on a POSIX system as leap seconds were inserted
or deleted.
These converted values can then be used in lieu of correcting the older
applications,
or when communicating with POSIX-compliant systems.
.PP
.I Time2posix
is single-valued.
That is,
every local time_t
corresponds to a single POSIX time_t.
.I Posix2time
is less well-behaved:
for a positive leap second hit the result is not unique,
and for a negative leap second hit the corresponding
POSIX time_t doesn't exist so an adjacent value is returned.
Both of these are good indicators of the inferiority of the
POSIX representation.
.PP
The following table summarizes the relationship between a time
T and it's conversion to,
and back from,
the POSIX representation over the leap second inserted at the end of June,
1993.
.nf
.ta \w'93/06/30 'u +\w'23:59:59 'u +\w'A+0 'u +\w'X=time2posix(T) 'u
DATE TIME T X=time2posix(T) posix2time(X)
93/06/30 23:59:59 A+0 B+0 A+0
93/06/30 23:59:60 A+1 B+1 A+1 or A+2
93/07/01 00:00:00 A+2 B+1 A+1 or A+2
93/07/01 00:00:01 A+3 B+2 A+3
A leap second deletion would look like...
DATE TIME T X=time2posix(T) posix2time(X)
??/06/30 23:59:58 A+0 B+0 A+0
??/07/01 00:00:00 A+1 B+2 A+1
??/07/01 00:00:01 A+2 B+3 A+2
.sp
.ce
[Note: posix2time(B+1) => A+0 or A+1]
.fi
.PP
If leap-second support is not enabled,
local time_t's and
POSIX time_t's are equivalent,
and both
.I time2posix
and
.I posix2time
degenerate to the identity function.
.SH SEE ALSO
difftime(3),
localtime(3),
mktime(3),
time(2)
.\" @(#)time2posix.3 7.3

134
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.TH TZFILE 5
.SH NAME
tzfile \- time zone information
.SH SYNOPSIS
.B
#include <tzfile.h>
.SH DESCRIPTION
The time zone information files used by
.IR tzset (3)
begin with bytes reserved for future use,
followed by six four-byte values of type
.BR long ,
written in a ``standard'' byte order
(the high-order byte of the value is written first).
These values are,
in order:
.TP
.I tzh_ttisgmtcnt
The number of GMT/local indicators stored in the file.
.TP
.I tzh_ttisstdcnt
The number of standard/wall indicators stored in the file.
.TP
.I tzh_leapcnt
The number of leap seconds for which data is stored in the file.
.TP
.I tzh_timecnt
The number of "transition times" for which data is stored
in the file.
.TP
.I tzh_typecnt
The number of "local time types" for which data is stored
in the file (must not be zero).
.TP
.I tzh_charcnt
The number of characters of "time zone abbreviation strings"
stored in the file.
.PP
The above header is followed by
.I tzh_timecnt
four-byte values of type
.BR long ,
sorted in ascending order.
These values are written in ``standard'' byte order.
Each is used as a transition time (as returned by
.IR time (2))
at which the rules for computing local time change.
Next come
.I tzh_timecnt
one-byte values of type
.BR "unsigned char" ;
each one tells which of the different types of ``local time'' types
described in the file is associated with the same-indexed transition time.
These values serve as indices into an array of
.I ttinfo
structures that appears next in the file;
these structures are defined as follows:
.in +.5i
.sp
.nf
.ta .5i +\w'unsigned int\0\0'u
struct ttinfo {
long tt_gmtoff;
int tt_isdst;
unsigned int tt_abbrind;
};
.in -.5i
.fi
.sp
Each structure is written as a four-byte value for
.I tt_gmtoff
of type
.BR long ,
in a standard byte order, followed by a one-byte value for
.I tt_isdst
and a one-byte value for
.IR tt_abbrind .
In each structure,
.I tt_gmtoff
gives the number of seconds to be added to GMT,
.I tt_isdst
tells whether
.I tm_isdst
should be set by
.I localtime (3)
and
.I tt_abbrind
serves as an index into the array of time zone abbreviation characters
that follow the
.I ttinfo
structure(s) in the file.
.PP
Then there are
.I tzh_leapcnt
pairs of four-byte values, written in standard byte order;
the first value of each pair gives the time
(as returned by
.IR time(2))
at which a leap second occurs;
the second gives the
.I total
number of leap seconds to be applied after the given time.
The pairs of values are sorted in ascending order by time.
.PP
Then there are
.I tzh_ttisstdcnt
standard/wall indicators, each stored as a one-byte value;
they tell whether the transition times associated with local time types
were specified as standard time or wall clock time,
and are used when a time zone file is used in handling POSIX-style
time zone environment variables.
.PP
Finally there are
.I tzh_ttisgmtcnt
GMT/local indicators, each stored as a one-byte value;
they tell whether the transition times associated with local time types
were specified as GMT or local time,
and are used when a time zone file is used in handling POSIX-style
time zone environment variables.
.PP
.I Localtime
uses the first standard-time
.I ttinfo
structure in the file
(or simply the first
.I ttinfo
structure in the absence of a standard-time structure)
if either
.I tzh_timecnt
is zero or the time argument is less than the first transition time recorded
in the file.
.SH SEE ALSO
newctime(3)
.\" @(#)tzfile.5 7.3

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#ifndef TZFILE_H
#define TZFILE_H
/*
** This header is for use ONLY with the time conversion code.
** There is no guarantee that it will remain unchanged,
** or that it will remain at all.
** Do NOT copy it to any system include directory.
** Thank you!
*/
/*
** ID
*/
#ifndef lint
#ifndef NOID
static char tzfilehid[] = "@(#)tzfile.h 7.6";
#endif /* !defined NOID */
#endif /* !defined lint */
/*
** Information about time zone files.
*/
#ifndef TZDIR
#define TZDIR "/usr/local/etc/zoneinfo" /* Time zone object file directory */
#endif /* !defined TZDIR */
#ifndef TZDEFAULT
#define TZDEFAULT "localtime"
#endif /* !defined TZDEFAULT */
#ifndef TZDEFRULES
#define TZDEFRULES "posixrules"
#endif /* !defined TZDEFRULES */
/*
** Each file begins with. . .
*/
struct tzhead {
char tzh_reserved[20]; /* reserved for future use */
char tzh_ttisgmtcnt[4]; /* coded number of trans. time flags */
char tzh_ttisstdcnt[4]; /* coded number of trans. time flags */
char tzh_leapcnt[4]; /* coded number of leap seconds */
char tzh_timecnt[4]; /* coded number of transition times */
char tzh_typecnt[4]; /* coded number of local time types */
char tzh_charcnt[4]; /* coded number of abbr. chars */
};
/*
** . . .followed by. . .
**
** tzh_timecnt (char [4])s coded transition times a la time(2)
** tzh_timecnt (unsigned char)s types of local time starting at above
** tzh_typecnt repetitions of
** one (char [4]) coded GMT offset in seconds
** one (unsigned char) used to set tm_isdst
** one (unsigned char) that's an abbreviation list index
** tzh_charcnt (char)s '\0'-terminated zone abbreviations
** tzh_leapcnt repetitions of
** one (char [4]) coded leap second transition times
** one (char [4]) total correction after above
** tzh_ttisstdcnt (char)s indexed by type; if TRUE, transition
** time is standard time, if FALSE,
** transition time is wall clock time
** if absent, transition times are
** assumed to be wall clock time
** tzh_ttisgmtcnt (char)s indexed by type; if TRUE, transition
** time is GMT, if FALSE,
** transition time is local time
** if absent, transition times are
** assumed to be local time
*/
/*
** In the current implementation, "tzset()" refuses to deal with files that
** exceed any of the limits below.
*/
#ifndef TZ_MAX_TIMES
/*
** The TZ_MAX_TIMES value below is enough to handle a bit more than a
** year's worth of solar time (corrected daily to the nearest second) or
** 138 years of Pacific Presidential Election time
** (where there are three time zone transitions every fourth year).
*/
#define TZ_MAX_TIMES 370
#endif /* !defined TZ_MAX_TIMES */
#ifndef TZ_MAX_TYPES
#ifndef NOSOLAR
#define TZ_MAX_TYPES 256 /* Limited by what (unsigned char)'s can hold */
#endif /* !defined NOSOLAR */
#ifdef NOSOLAR
/*
** Must be at least 14 for Europe/Riga as of Jan 12 1995,
** as noted by Earl Chew <earl@hpato.aus.hp.com>.
*/
#define TZ_MAX_TYPES 20 /* Maximum number of local time types */
#endif /* !defined NOSOLAR */
#endif /* !defined TZ_MAX_TYPES */
#ifndef TZ_MAX_CHARS
#define TZ_MAX_CHARS 50 /* Maximum number of abbreviation characters */
/* (limited by what unsigned chars can hold) */
#endif /* !defined TZ_MAX_CHARS */
#ifndef TZ_MAX_LEAPS
#define TZ_MAX_LEAPS 50 /* Maximum number of leap second corrections */
#endif /* !defined TZ_MAX_LEAPS */
#define SECSPERMIN 60
#define MINSPERHOUR 60
#define HOURSPERDAY 24
#define DAYSPERWEEK 7
#define DAYSPERNYEAR 365
#define DAYSPERLYEAR 366
#define SECSPERHOUR (SECSPERMIN * MINSPERHOUR)
#define SECSPERDAY ((long) SECSPERHOUR * HOURSPERDAY)
#define MONSPERYEAR 12
#define TM_SUNDAY 0
#define TM_MONDAY 1
#define TM_TUESDAY 2
#define TM_WEDNESDAY 3
#define TM_THURSDAY 4
#define TM_FRIDAY 5
#define TM_SATURDAY 6
#define TM_JANUARY 0
#define TM_FEBRUARY 1
#define TM_MARCH 2
#define TM_APRIL 3
#define TM_MAY 4
#define TM_JUNE 5
#define TM_JULY 6
#define TM_AUGUST 7
#define TM_SEPTEMBER 8
#define TM_OCTOBER 9
#define TM_NOVEMBER 10
#define TM_DECEMBER 11
#define TM_YEAR_BASE 1900
#define EPOCH_YEAR 1970
#define EPOCH_WDAY TM_THURSDAY
/*
** Accurate only for the past couple of centuries;
** that will probably do.
*/
#define isleap(y) ((((y) % 4) == 0 && ((y) % 100) != 0) || ((y) % 400) == 0)
#ifndef USG
/*
** Use of the underscored variants may cause problems if you move your code to
** certain System-V-based systems; for maximum portability, use the
** underscore-free variants. The underscored variants are provided for
** backward compatibility only; they may disappear from future versions of
** this file.
*/
#define SECS_PER_MIN SECSPERMIN
#define MINS_PER_HOUR MINSPERHOUR
#define HOURS_PER_DAY HOURSPERDAY
#define DAYS_PER_WEEK DAYSPERWEEK
#define DAYS_PER_NYEAR DAYSPERNYEAR
#define DAYS_PER_LYEAR DAYSPERLYEAR
#define SECS_PER_HOUR SECSPERHOUR
#define SECS_PER_DAY SECSPERDAY
#define MONS_PER_YEAR MONSPERYEAR
#endif /* !defined USG */
#endif /* !defined TZFILE_H */