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strftime fix for big years etc.; plus documentation cleanup
|
From: |
Paul Eggert |
|
Subject: |
strftime fix for big years etc.; plus documentation cleanup |
|
Date: |
Wed, 23 Feb 2005 16:39:26 -0800 |
I installed this coreutils patch to fix some problems with outlandish
years (which are possible on 64-bit hosts with "date") and other
problems, and to bring the documentation back in sync with the code.
2005-02-23 Paul Eggert <address@hidden>
* doc/coreutils.texi: Adjust to match current strftime.c.
(Time directives): Say that %k, %l, and %P are GNU extensions.
For %p and %P, mention handling of noon and midnight.
For %s, use ISO 8601, and mention handling of leap seconds.
For %S, clarify mention of leap seconds.
For %T, say that it's the same as %H:%M:%S.
For %X, don't say that it must be the same as %H:%M:%S.
For %z and %Z, clarify which time zones are used. These options
are now affected by --date, so don't claim that they're not.
(Date directives): %C is now all but the last two chars of %Y.
For %D, say that it's equivalent to %m/%d/%y.
For %e, use blank in example.
For %h, use @code for %b.
For %Y, mention what happens with outlandish years.
(Padding and other flags): Renamed from Padding.
Mention that the flags are GNU extensions.
Mention the 0 and ^ flags.
Mention field widths an modifiers.
(Examples of date): - is a flag, not a modifier.
* lib/strftime.c: Include <stdbool.h>. Use bool where appropriate,
instead of int.
(my_strftime): Do not mishandle years close to INT_MAX, by doing
the right thing even if adding 1900 would overflow. Similarly
for tm_mon + 1 and tm_yday + 1.
Make %Y always equivalent to %C%y, and similarly for %G and %g.
(DO_NUMBER, DO_NUMBER_SPACEPAD): Set digits to d, not a conditional.
(DO_SIGNED_NUMBER): New macro.
(my_strftime) [HAVE_TZNAME]: Don't dump core if tp->tm_dst > 1.
Index: doc/coreutils.texi
===================================================================
RCS file: /fetish/cu/doc/coreutils.texi,v
retrieving revision 1.241
diff -p -u -r1.241 coreutils.texi
--- doc/coreutils.texi 8 Feb 2005 21:38:04 -0000 1.241
+++ doc/coreutils.texi 24 Feb 2005 00:26:11 -0000
@@ -398,7 +398,7 @@ System context
* Time directives:: Time directives
* Date directives:: Date directives
* Literal directives:: Literal directives
-* Padding:: Padding
+* Padding and other flags:: Padding and other flags
* Setting the time:: Setting the time
* Options for date:: Options for @command{date}
* Examples of date:: Examples of @command{date}
@@ -11441,7 +11441,7 @@ are printed unchanged. The directives a
* Time directives:: %[HIklMprsSTXzZ]
* Date directives:: %[aAbBcCdDhjmUwWxyY]
* Literal directives:: %[%nt]
-* Padding:: Pad with zeroes, spaces (%_), or nothing (%-).
+* Padding and other flags:: Pad with zeroes, spaces (%_), etc.
* Setting the time:: Changing the system clock.
* Options for date:: Instead of the current time.
* Examples of date:: Examples.
@@ -11461,44 +11461,51 @@ hour (address@hidden)
@item %I
hour (address@hidden)
@item %k
-hour ( address@hidden)
+hour ( address@hidden).
+This is a @acronym{GNU} extension.
@item %l
-hour ( address@hidden)
+hour ( address@hidden).
+This is a @acronym{GNU} extension.
@item %M
minute (address@hidden)
@item %N
nanoseconds (address@hidden)
@item %p
-locale's upper case @samp{AM} or @samp{PM} (blank in many locales)
+locale's upper case @samp{AM} or @samp{PM} (blank in many locales).
+Noon is treated as @samp{PM} and midnight as @samp{AM}.
@item %P
-locale's lower case @samp{am} or @samp{pm} (blank in many locales)
+locale's lower case @samp{am} or @samp{pm} (blank in many locales).
+Noon is treated as @samp{pm} and midnight as @samp{am}.
+This is a @acronym{GNU} extension.
@item %r
-time, 12-hour (hh:mm:ss [AP]M)
+locale's 12-hour time (hh:mm:ss [AP]M)
@item %R
-time, 24-hour (hh:mm). Same as @code{%H:%M}.
+24-hour hour and minute. Same as @code{%H:%M}.
@item %s
@cindex epoch, seconds since
@cindex seconds since the epoch
@cindex beginning of time
-seconds since the epoch, i.e., 1 January 1970 00:00:00 UTC (a GNU extension).
-For examples, @xref{%s-examples}.
+seconds since the epoch, i.e., since 1970-01-01 00:00:00 UTC.
+Leap seconds are not counted unless leap second support is available.
+This is a @acronym{GNU} extension.
address@hidden, for examples.
@item %S
-second (address@hidden). The range is address@hidden, and not address@hidden,
-in order to accommodate the occasional positive leap second.
+second (address@hidden). This may be @samp{60} if leap seconds are supported.
@item %T
-time, 24-hour (hh:mm:ss)
+24-hour hour, minute, and second. Same as @code{%H:%M:%S}.
@item %X
-locale's time representation (%H:%M:%S)
+locale's time representation (hh:mm:ss)
@item %z
-RFC-2822 style numeric time zone (e.g., @samp{-0600} or @samp{+0100}),
-or nothing if no
-time zone is determinable. This value reflects the @emph{current} time
-zone. It isn't changed by the @option{--date} option.
address@hidden 2822}/@w{ISO 8601} style numeric time zone (e.g., @samp{-0600}
+or @samp{+0100}), or nothing if no
+time zone is determinable. This value reflects the numeric time zone
+appropriate for the current time, using the time zone rules specified
+by the @env{TZ} environment variable.
+The time (and optionally, the time zone rules) can be overridden
+by the @option{--date} option.
@item %Z
-time zone (e.g., EDT), or nothing if no time zone is
-determinable.
-Note that this value reflects the @emph{current} time zone.
-It isn't changed by the @option{--date} option.
+alphabetic time zone abbreviation (e.g., @samp{EDT}), or nothing if no
+time zone is determinable. See @samp{%z} for how it is determined.
@end table
@@ -11522,13 +11529,16 @@ locale's full month name, variable lengt
@item %c
locale's date and time (Sat Nov 04 12:02:33 EST 1989)
@item %C
-century (year divided by 100 and truncated to an integer) (address@hidden)
+century. This is like @code{%Y}, except the last two digits are omitted.
+For example, it is @samp{20} if @code{%Y} is @samp{2000},
+and is @samp{-0} if @code{%Y} is @samp{-001}.
+It is normally at least two characters, but it may be more.
@item %d
day of month (address@hidden)
@item %D
-date (mm/dd/yy)
+date (equivalent to @code{%m/%d/%y})
@item %e
-blank-padded day of month (address@hidden)
+blank-padded day of month ( address@hidden)
@item %F
the @w{ISO 8601} standard date format: @code{%Y-%m-%d}.
This is the preferred form for all uses.
@@ -11543,7 +11553,7 @@ and value as @code{%Y}, except that if t
@code{%V}) belongs to the previous or next year, that year is used
instead.
@item %h
-same as %b
+same as @code{%b}
@item %j
day of year (address@hidden)
@item %m
@@ -11569,7 +11579,8 @@ locale's date representation (mm/dd/yy)
@item %y
last two digits of year (address@hidden)
@item %Y
-year (address@hidden)
+year. This is normally at least four characters, but it may be more.
+Year 0000 precedes year 0001, and year -001 precedes year 0000.
@end table
@@ -11591,8 +11602,8 @@ a horizontal tab
@end table
address@hidden Padding
address@hidden Padding
address@hidden Padding and other flags
address@hidden Padding and other flags
@cindex numeric field padding
@cindex padding of numeric fields
@@ -11600,9 +11611,11 @@ a horizontal tab
By default, @command{date} pads numeric fields with zeroes, so that, for
example, numeric months are always output as two digits.
address@hidden @command{date}
-recognizes the following numeric modifiers between the @samp{%} and the
-directive.
+Numbers that do not have a range are never
+padded, since there is no natural width for them.
+
+As a @acronym{GNU} extension, @command{date} recognizes any of the
+following optional flags after the @samp{%}:
@table @samp
@item -
@@ -11611,12 +11624,14 @@ human consumption.
@item _
(underscore) pad the field with spaces; useful if you need a fixed
number of characters in the output, but zeroes are too distracting.
address@hidden 0
+(zero) Pad with zeros even if the format specifies padding with spaces.
address@hidden ^
+Use upper case characters if possible.
@end table
@noindent
-These are GNU extensions.
-
-Here is an example illustrating the differences:
+Here are some examples of padding:
@example
date +%d/%m -d "Feb 1"
@@ -11627,6 +11642,31 @@ date +%_d/%_m -d "Feb 1"
@result{} 1/ 2
@end example
+As a @acronym{GNU} extension, you can specify the field width
+after any flag, as a decimal number. If the natural size of the
+output is of the field has less than the specified number of characters,
+the result is written right adjusted and space padded to the given
+size.
+
+An optional modifier can follow the optional flag and width
+specification. The modifiers are:
+
address@hidden @code
address@hidden E
+Use the locale's alternate representation for date and time. This
+modifier applies to the @code{%c}, @code{%C}, @code{%x}, @code{%X},
address@hidden and @code{%Y} format specifiers. In a Japanese locale, for
+example, @code{%Ex} might yield a date format based on the Japanese
+Emperors' reigns.
+
address@hidden O
+Use the locale's alternate numeric symbols for numbers. This modifier
+applies only to numeric format specifiers.
address@hidden table
+
+If the format supports the modifier but no alternate representation
+is available, it is ignored.
+
@node Setting the time
@subsection Setting the time
@@ -11837,7 +11877,8 @@ for example @samp{date -d 1may '+%B %d'}
@item
To print a date without the leading zero for one-digit days
-of the month, you can use the (GNU extension) @code{-} modifier to suppress
+of the month, you can use the (@acronym{GNU} extension)
address@hidden flag to suppress
the padding altogether:
@example
@@ -11846,7 +11887,7 @@ date -d 1may '+%B %-d
@item
To print the current date and time in the format required by many
-non-GNU versions of @command{date} when setting the system clock:
address@hidden versions of @command{date} when setting the system clock:
@example
date +%m%d%H%M%Y.%S
Index: lib/strftime.c
===================================================================
RCS file: /fetish/cu/lib/strftime.c,v
retrieving revision 1.78
diff -p -u -r1.78 strftime.c
--- lib/strftime.c 11 Nov 2004 06:07:57 -0000 1.78
+++ lib/strftime.c 24 Feb 2005 00:26:12 -0000
@@ -1,4 +1,4 @@
-/* Copyright (C) 1991-1999, 2000, 2001, 2003, 2004 Free Software
+/* Copyright (C) 1991-1999, 2000, 2001, 2003, 2004, 2005 Free Software
Foundation, Inc.
NOTE: The canonical source of this file is maintained with the GNU C
Library.
@@ -72,6 +72,7 @@ extern char *tzname[];
#endif
#include <limits.h>
+#include <stdbool.h>
#include <stddef.h>
#include <stdlib.h>
#include <string.h>
@@ -479,16 +480,17 @@ my_strftime (CHAR_T *s, size_t maxsize,
int modifier; /* Field modifier ('E', 'O', or 0). */
int digits; /* Max digits for numeric format. */
int number_value; /* Numeric value to be printed. */
- int negative_number; /* 1 if the number is negative. */
+ unsigned int u_number_value; /* (unsigned int) number_value. */
+ bool negative_number; /* 1 if the number is negative. */
const CHAR_T *subfmt;
CHAR_T *bufp;
CHAR_T buf[1 + (sizeof (int) < sizeof (time_t)
? INT_STRLEN_BOUND (time_t)
: INT_STRLEN_BOUND (int))];
int width = -1;
- int to_lowcase = 0;
- int to_uppcase = 0;
- int change_case = 0;
+ bool to_lowcase = false;
+ bool to_uppcase = false;
+ bool change_case = false;
int format_char;
#if DO_MULTIBYTE && !defined COMPILE_WIDE
@@ -593,10 +595,10 @@ my_strftime (CHAR_T *s, size_t maxsize,
/* This changes textual output. */
case L_('^'):
- to_uppcase = 1;
+ to_uppcase = true;
continue;
case L_('#'):
- change_case = 1;
+ change_case = true;
continue;
default:
@@ -643,10 +645,14 @@ my_strftime (CHAR_T *s, size_t maxsize,
switch (format_char)
{
#define DO_NUMBER(d, v) \
- digits = d > width ? d : width; \
+ digits = d; \
number_value = v; goto do_number
+#define DO_SIGNED_NUMBER(d, negative, v) \
+ digits = d; \
+ negative_number = negative; \
+ u_number_value = v; goto do_signed_number
#define DO_NUMBER_SPACEPAD(d, v) \
- digits = d > width ? d : width; \
+ digits = d; \
number_value = v; goto do_number_spacepad
case L_('%'):
@@ -660,8 +666,8 @@ my_strftime (CHAR_T *s, size_t maxsize,
goto bad_format;
if (change_case)
{
- to_uppcase = 1;
- to_lowcase = 0;
+ to_uppcase = true;
+ to_lowcase = false;
}
#if defined _NL_CURRENT || !HAVE_STRFTIME
cpy (aw_len, a_wkday);
@@ -675,8 +681,8 @@ my_strftime (CHAR_T *s, size_t maxsize,
goto bad_format;
if (change_case)
{
- to_uppcase = 1;
- to_lowcase = 0;
+ to_uppcase = true;
+ to_lowcase = false;
}
#if defined _NL_CURRENT || !HAVE_STRFTIME
cpy (STRLEN (f_wkday), f_wkday);
@@ -689,8 +695,8 @@ my_strftime (CHAR_T *s, size_t maxsize,
case L_('h'):
if (change_case)
{
- to_uppcase = 1;
- to_lowcase = 0;
+ to_uppcase = true;
+ to_lowcase = false;
}
if (modifier != 0)
goto bad_format;
@@ -706,8 +712,8 @@ my_strftime (CHAR_T *s, size_t maxsize,
goto bad_format;
if (change_case)
{
- to_uppcase = 1;
- to_lowcase = 0;
+ to_uppcase = true;
+ to_lowcase = false;
}
#if defined _NL_CURRENT || !HAVE_STRFTIME
cpy (STRLEN (f_month), f_month);
@@ -807,8 +813,9 @@ my_strftime (CHAR_T *s, size_t maxsize,
}
{
- int year = tp->tm_year + TM_YEAR_BASE;
- DO_NUMBER (1, year / 100 - (year % 100 < 0));
+ int century = tp->tm_year / 100 + TM_YEAR_BASE / 100;
+ century -= tp->tm_year % 100 < 0 && 0 < century;
+ DO_SIGNED_NUMBER (2, tp->tm_year < - TM_YEAR_BASE, century);
}
case L_('x'):
@@ -846,8 +853,8 @@ my_strftime (CHAR_T *s, size_t maxsize,
DO_NUMBER_SPACEPAD (2, tp->tm_mday);
- /* All numeric formats set DIGITS and NUMBER_VALUE and then
- jump to one of these two labels. */
+ /* All numeric formats set DIGITS and NUMBER_VALUE (or U_NUMBER_VALUE)
+ and then jump to one of these three labels. */
do_number_spacepad:
/* Force `_' flag unless overridden by `0' or `-' flag. */
@@ -855,14 +862,22 @@ my_strftime (CHAR_T *s, size_t maxsize,
pad = L_('_');
do_number:
- /* Format the number according to the MODIFIER flag. */
-
- if (modifier == L_('O') && 0 <= number_value)
+ /* Format NUMBER_VALUE according to the MODIFIER flag. */
+ negative_number = number_value < 0;
+ u_number_value = number_value;
+
+ do_signed_number:
+ /* Format U_NUMBER_VALUE according to the MODIFIER flag.
+ NEGATIVE_NUMBER is nonzero if the original number was
+ negative; in this case it was converted directly to
+ unsigned int (i.e., modulo (UINT_MAX + 1)) without
+ negating it. */
+ if (modifier == L_('O') && !negative_number)
{
#ifdef _NL_CURRENT
/* Get the locale specific alternate representation of
- the number NUMBER_VALUE. If none exist NULL is returned. */
- const CHAR_T *cp = nl_get_alt_digit (number_value
+ the number. If none exist NULL is returned. */
+ const CHAR_T *cp = nl_get_alt_digit (u_number_value
HELPER_LOCALE_ARG);
if (cp != NULL)
@@ -880,19 +895,21 @@ my_strftime (CHAR_T *s, size_t maxsize,
# endif
#endif
}
- {
- unsigned int u = number_value;
- bufp = buf + sizeof (buf) / sizeof (buf[0]);
- negative_number = number_value < 0;
+ bufp = buf + sizeof (buf) / sizeof (buf[0]);
- if (negative_number)
- u = -u;
+ if (negative_number)
+ u_number_value = - u_number_value;
- do
- *--bufp = u % 10 + L_('0');
- while ((u /= 10) != 0);
- }
+ do
+ {
+ *--bufp = u_number_value % 10 + L_('0');
+ u_number_value /= 10;
+ }
+ while (u_number_value != 0);
+
+ if (digits < width)
+ digits = width;
do_number_sign_and_padding:
if (negative_number)
@@ -974,7 +991,7 @@ my_strftime (CHAR_T *s, size_t maxsize,
if (modifier == L_('E'))
goto bad_format;
- DO_NUMBER (3, 1 + tp->tm_yday);
+ DO_SIGNED_NUMBER (3, tp->tm_yday < -1, tp->tm_yday + 1U);
case L_('M'):
if (modifier == L_('E'))
@@ -986,7 +1003,7 @@ my_strftime (CHAR_T *s, size_t maxsize,
if (modifier == L_('E'))
goto bad_format;
- DO_NUMBER (2, tp->tm_mon + 1);
+ DO_SIGNED_NUMBER (2, tp->tm_mon < -1, tp->tm_mon + 1U);
#ifndef _LIBC
case L_('N'): /* GNU extension. */
@@ -1010,7 +1027,7 @@ my_strftime (CHAR_T *s, size_t maxsize,
break;
case L_('P'):
- to_lowcase = 1;
+ to_lowcase = true;
#if !defined _NL_CURRENT && HAVE_STRFTIME
format_char = L_('p');
#endif
@@ -1019,8 +1036,8 @@ my_strftime (CHAR_T *s, size_t maxsize,
case L_('p'):
if (change_case)
{
- to_uppcase = 0;
- to_lowcase = 1;
+ to_uppcase = false;
+ to_lowcase = true;
}
#if defined _NL_CURRENT || !HAVE_STRFTIME
cpy (ap_len, ampm);
@@ -1070,20 +1087,7 @@ my_strftime (CHAR_T *s, size_t maxsize,
{
int d = t % 10;
t /= 10;
-
- if (negative_number)
- {
- d = -d;
-
- /* Adjust if division truncates to minus infinity. */
- if (0 < -1 % 10 && d < 0)
- {
- t++;
- d += 10;
- }
- }
-
- *--bufp = d + L_('0');
+ *--bufp = (negative_number ? -d : d) + L_('0');
}
while (t != 0);
@@ -1131,14 +1135,22 @@ my_strftime (CHAR_T *s, size_t maxsize,
if (modifier == L_('E'))
goto bad_format;
{
- int year = tp->tm_year + TM_YEAR_BASE;
+ /* YEAR is a leap year if and only if (tp->tm_year + TM_YEAR_BASE)
+ is a leap year, except that YEAR and YEAR - 1 both work
+ correctly even when (tp->tm_year + TM_YEAR_BASE) would
+ overflow. */
+ int year = (tp->tm_year
+ + (tp->tm_year < 0
+ ? TM_YEAR_BASE % 400
+ : TM_YEAR_BASE % 400 - 400));
+ int year_adjust = 0;
int days = iso_week_days (tp->tm_yday, tp->tm_wday);
if (days < 0)
{
/* This ISO week belongs to the previous year. */
- year--;
- days = iso_week_days (tp->tm_yday + (365 + __isleap (year)),
+ year_adjust = -1;
+ days = iso_week_days (tp->tm_yday + (365 + __isleap (year - 1)),
tp->tm_wday);
}
else
@@ -1148,7 +1160,7 @@ my_strftime (CHAR_T *s, size_t maxsize,
if (0 <= d)
{
/* This ISO week belongs to the next year. */
- year++;
+ year_adjust = 1;
days = d;
}
}
@@ -1156,10 +1168,19 @@ my_strftime (CHAR_T *s, size_t maxsize,
switch (*f)
{
case L_('g'):
- DO_NUMBER (2, (year % 100 + 100) % 100);
+ {
+ int yy = (tp->tm_year % 100 + year_adjust) % 100;
+ DO_NUMBER (2, (0 <= yy
+ ? yy
+ : tp->tm_year < -TM_YEAR_BASE - year_adjust
+ ? -yy
+ : yy + 100));
+ }
case L_('G'):
- DO_NUMBER (1, year);
+ DO_SIGNED_NUMBER (4, tp->tm_year < -TM_YEAR_BASE - year_adjust,
+ (tp->tm_year + (unsigned int) TM_YEAR_BASE
+ + year_adjust));
default:
DO_NUMBER (2, days / 7 + 1);
@@ -1201,7 +1222,8 @@ my_strftime (CHAR_T *s, size_t maxsize,
if (modifier == L_('O'))
goto bad_format;
else
- DO_NUMBER (1, tp->tm_year + TM_YEAR_BASE);
+ DO_SIGNED_NUMBER (4, tp->tm_year < -TM_YEAR_BASE,
+ tp->tm_year + (unsigned int) TM_YEAR_BASE);
case L_('y'):
if (modifier == L_('E'))
@@ -1220,19 +1242,25 @@ my_strftime (CHAR_T *s, size_t maxsize,
# endif
#endif
}
- DO_NUMBER (2, (tp->tm_year % 100 + 100) % 100);
+
+ {
+ int yy = tp->tm_year % 100;
+ if (yy < 0)
+ yy = tp->tm_year < - TM_YEAR_BASE ? -yy : yy + 100;
+ DO_NUMBER (2, yy);
+ }
case L_('Z'):
if (change_case)
{
- to_uppcase = 0;
- to_lowcase = 1;
+ to_uppcase = false;
+ to_lowcase = true;
}
#if HAVE_TZNAME
/* The tzset() call might have changed the value. */
if (!(zone && *zone) && tp->tm_isdst >= 0)
- zone = tzname[tp->tm_isdst];
+ zone = tzname[tp->tm_isdst != 0];
#endif
if (! zone)
zone = "";
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- strftime fix for big years etc.; plus documentation cleanup,
Paul Eggert <=