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2005-02-16 Eric Blake <ebb9@byu.net> 

* libc/time/time.tex: Improve the documentation.
        * libc/time/strftime.c: Improve the documentation.
        (iso_year_adjust): New helper function.
        (strftime): Simplify '%E' and '%O'. Change '%c' to use
        recursion. Fix '%C', '%y', and '%Y' to deal with years with more
        than 4 characters.  Combine '%d' and '%e'. Implement '%D', '%F',
        '%g', '%G', '%n', '%R', '%t', '%T', '%u', '%V', '%X', and '%z'.
        Avoid core dumps on valid inputs (maxsize == 0, or
        tim_p->tm_isdst > 1).
This commit is contained in:
Jeff Johnston 2005-02-16 21:15:37 +00:00
parent 031619634c
commit f1d439fc64
3 changed files with 440 additions and 177 deletions

12
newlib/ChangeLog
View File

@ -1,3 +1,15 @@
2005-02-16 Eric Blake <ebb9@byu.net>
* libc/time/time.tex: Improve the documentation.
* libc/time/strftime.c: Improve the documentation.
(iso_year_adjust): New helper function.
(strftime): Simplify '%E' and '%O'. Change '%c' to use
recursion. Fix '%C', '%y', and '%Y' to deal with years with more
than 4 characters. Combine '%d' and '%e'. Implement '%D', '%F',
'%g', '%G', '%n', '%R', '%t', '%T', '%u', '%V', '%X', and '%z'.
Avoid core dumps on valid inputs (maxsize == 0, or
tim_p->tm_isdst > 1).
2005-02-08 Corinna Vinschen <corinna@vinschen.de> 2005-02-08 Corinna Vinschen <corinna@vinschen.de>
* libc/include/pwd.h (struct passwd): Change pw_uid and pw_gid * libc/include/pwd.h (struct passwd): Change pw_uid and pw_gid

589
newlib/libc/time/strftime.c
View File

@ -32,96 +32,195 @@ TRAD_SYNOPSIS
DESCRIPTION DESCRIPTION
<<strftime>> converts a <<struct tm>> representation of the time (at <<strftime>> converts a <<struct tm>> representation of the time (at
<[timp]>) into a string, starting at <[s]> and occupying no more than <[timp]>) into a null-terminated string, starting at <[s]> and occupying
<[maxsize]> characters. no more than <[maxsize]> characters.
You control the format of the output using the string at <[format]>. You control the format of the output using the string at <[format]>.
<<*<[format]>>> can contain two kinds of specifications: text to be <<*<[format]>>> can contain two kinds of specifications: text to be
copied literally into the formatted string, and time conversion copied literally into the formatted string, and time conversion
specifications. Time conversion specifications are two-character specifications. Time conversion specifications are two- and
sequences beginning with `<<%>>' (use `<<%%>>' to include a percent three-character sequences beginning with `<<%>>' (use `<<%%>>' to
sign in the output). Each defined conversion specification selects a include a percent sign in the output). Each defined conversion
field of calendar time data from <<*<[timp]>>>, and converts it to a specification selects only the specified field(s) of calendar time
string in one of the following ways: data from <<*<[timp]>>>, and converts it to a string in one of the
following ways:
o+ o+
o %a o %a
An abbreviation for the day of the week. A three-letter abbreviation for the day of the week. [tm_wday]
o %A o %A
The full name for the day of the week. The full name for the day of the week, one of `<<Sunday>>',
`<<Monday>>', `<<Tuesday>>', `<<Wednesday>>', `<<Thursday>>',
`<<Friday>>', or `<<Saturday>>'. [tm_wday]
o %b o %b
An abbreviation for the month name. A three-letter abbreviation for the month name. [tm_mon]
o %B o %B
The full name of the month. The full name of the month, one of `<<January>>', `<<February>>',
`<<March>>', `<<April>>', `<<May>>', `<<June>>', `<<July>>',
`<<August>>', `<<September>>', `<<October>>', `<<November>>',
`<<December>>'. [tm_mon]
o %c o %c
A string representing the complete date and time, in the form A string representing the complete date and time, in the form
. Mon Apr 01 13:13:13 1992 `<<"%a %b %e %H:%M:%S %Y">>' (example "Mon Apr 01 13:13:13
1992"). [tm_sec, tm_min, tm_hour, tm_mday, tm_mon, tm_year, tm_wday]
o %C
The century, that is, the year divided by 100 then truncated. For
4-digit years, the result is zero-padded and exactly two characters;
but for other years, there may a negative sign or more digits. In
this way, `<<%C%y>>' is equivalent to `<<%Y>>'. [tm_year]
o %d o %d
The day of the month, formatted with two digits. The day of the month, formatted with two digits (from `<<01>>' to
`<<31>>'). [tm_mday]
o %D
A string representing the date, in the form `<<"%m/%d/%y">>'.
[tm_mday, tm_mon, tm_year]
o %e o %e
The day of the month, formatted with leading space if single digit. The day of the month, formatted with leading space if single digit
(from `<< 1>>' to `<<31>>'). [tm_mday]
o %E<<x>>
In some locales, the E modifier selects alternative representations of
certain modifiers <<x>>. But in the "C" locale supported by newlib,
it is ignored, and treated as %<<x>>.
o %F
A string representing the ISO 8601:2000 date format, in the form
`<<"%Y-%m-%d">>'. [tm_mday, tm_mon, tm_year]
o %g
The last two digits of the week-based year, see specifier %G (from
`<<00>>' to `<<99>>'). [tm_year, tm_wday, tm_yday]
o %G
The week-based year. In the ISO 8601:2000 calendar, week 1 of the year
includes January 4th, and begin on Mondays. Therefore, if January 1st,
2nd, or 3rd falls on a Sunday, that day and earlier belong to week 53
of the previous year; and if December 29th, 30th, or 31st falls on
Monday, that day and later belong to week 1 of the next year. For
consistency with %Y, it always has at least four characters.
Example: "%G" for Saturday 2nd January 1999 gives "1998", and for
Tuesday 30th December 1997 gives "1998". [tm_year, tm_wday, tm_yday]
o %h
A three-letter abbreviation for the month name (synonym for
"%b"). [tm_mon]
o %H o %H
The hour (on a 24-hour clock), formatted with two digits. The hour (on a 24-hour clock), formatted with two digits (from
`<<00>>' to `<<23>>'). [tm_hour]
o %I o %I
The hour (on a 12-hour clock), formatted with two digits. The hour (on a 12-hour clock), formatted with two digits (from
`<<01>>' to `<<12>>'). [tm_hour]
o %j o %j
The count of days in the year, formatted with three digits The count of days in the year, formatted with three digits
(from `<<001>>' to `<<366>>'). (from `<<001>>' to `<<366>>'). [tm_yday]
o %k
The hour (on a 24-hour clock), formatted with leading space if single
digit (from `<< 0>>' to `<<23>>'). Non-POSIX extension. [tm_hour]
o %l
The hour (on a 12-hour clock), formatted with leading space if single
digit (from `<< 1>>' to `<<12>>'). Non-POSIX extension. [tm_hour]
o %m o %m
The month number, formatted with two digits. The month number, formatted with two digits (from `<<01>>' to `<<12>>').
[tm_mon]
o %M o %M
The minute, formatted with two digits. The minute, formatted with two digits (from `<<00>>' to `<<59>>'). [tm_min]
o %n
A newline character (`<<\n>>').
o %O<<x>>
In some locales, the O modifier selects alternative digit characters
for certain modifiers <<x>>. But in the "C" locale supported by newlib, it
is ignored, and treated as %<<x>>.
o %p o %p
Either `<<AM>>' or `<<PM>>' as appropriate. Either `<<AM>>' or `<<PM>>' as appropriate. [tm_hour]
o %r o %r
Equivalent to "%I:%M:%S %p". The 12-hour time, to the second. Equivalent to "%I:%M:%S %p". [tm_sec,
tm_min, tm_hour]
o %R
The 24-hour time, to the minute. Equivalent to "%H:%M". [tm_min, tm_hour]
o %S o %S
The second, formatted with two digits. The second, formatted with two digits (from `<<00>>' to `<<60>>'). The
value 60 accounts for the occasional leap second. [tm_sec]
o %t
A tab character (`<<\t>>').
o %T
The 24-hour time, to the second. Equivalent to "%H:%M:%S". [tm_sec,
tm_min, tm_hour]
o %u
The weekday as a number, 1-based from Monday (from `<<1>>' to
`<<7>>'). [tm_wday]
o %U o %U
The week number, formatted with two digits (from `<<00>>' to `<<53>>'; The week number, where weeks start on Sunday, week 1 contains the first
week number 1 is taken as beginning with the first Sunday in a year). Sunday in a year, and earlier days are in week 0. Formatted with two
See also <<%W>>. digits (from `<<00>>' to `<<53>>'). See also <<%W>>. [tm_wday, tm_yday]
o %V
The week number, where weeks start on Monday, week 1 contains January 4th,
and earlier days are in the previous year. Formatted with two digits
(from `<<01>>' to `<<53>>'). See also <<%G>>. [tm_year, tm_wday, tm_yday]
o %w o %w
A single digit representing the day of the week: Sunday is day <<0>>. The weekday as a number, 0-based from Sunday (from `<<0>>' to `<<6>>').
[tm_wday]
o %W o %W
Another version of the week number: like `<<%U>>', but counting week 1 The week number, where weeks start on Monday, week 1 contains the first
as beginning with the first Monday in a year. Monday in a year, and earlier days are in week 0. Formatted with two
digits (from `<<00>>' to `<<53>>'). [tm_wday, tm_yday]
o
o %x o %x
A string representing the complete date, equivalent to "%m/%d/%y". A string representing the complete date, equivalent to "%m/%d/%y".
[tm_mon, tm_mday, tm_year]
o %X o %X
A string representing the full time of day (hours, minutes, and A string representing the full time of day (hours, minutes, and
seconds), equivalent to "%T". seconds), equivalent to "%H:%M:%S". [tm_sec, tm_min, tm_hour]
o %y o %y
The last two digits of the year. The last two digits of the year (from `<<00>>' to `<<99>>'). [tm_year]
o %Y o %Y
The full year, formatted with four digits to include the century. The full year, equivalent to <<%C%y>>. It will always have at least four
characters, but may have more. The year is accurate even when tm_year
added to the offset of 1900 overflows an int. [tm_year]
o %z
The offset from UTC. The format consists of a sign (negative is west of
Greewich), two characters for hour, then two characters for minutes
(-hhmm or +hhmm). If tm_isdst is negative, the offset is unknown and no
output is generated; if it is zero, the offset is the standard offset for
the current time zone; and if it is positive, the offset is the daylight
savings offset for the current timezone. The offset is determined from
the TZ environment variable, as if by calling tzset(). [tm_isdst]
o %Z o %Z
The time zone name. If tm_isdst is -1, no output is generated. The time zone name. If tm_isdst is negative, no output is generated.
Otherwise, the time zone name based on the TZ environment variable Otherwise, the time zone name is based on the TZ environment variable,
is used. as if by calling tzset(). [tm_isdst]
o %% o %%
A single character, `<<%>>'. A single character, `<<%>>'.
@ -138,7 +237,12 @@ parts of <<*<[format]>>> that could be completely filled in within the
PORTABILITY PORTABILITY
ANSI C requires <<strftime>>, but does not specify the contents of ANSI C requires <<strftime>>, but does not specify the contents of
<<*<[s]>>> when the formatted string would require more than <<*<[s]>>> when the formatted string would require more than
<[maxsize]> characters. <[maxsize]> characters. Unrecognized specifiers and fields of
<<timp>> that are out of range cause undefined results. Since some
formats expand to 0 bytes, it is wise to set <<*<[s]>>> to a nonzero
value beforehand to distinguish between failure and an empty string.
This implementation does not support <<s>> being NULL, nor overlapping
<<s>> and <<format>>.
<<strftime>> requires no supporting OS subroutines. <<strftime>> requires no supporting OS subroutines.
*/ */
@ -147,6 +251,7 @@ ANSI C requires <<strftime>>, but does not specify the contents of
#include <stdio.h> #include <stdio.h>
#include <time.h> #include <time.h>
#include <string.h> #include <string.h>
#include <stdlib.h>
#include "local.h" #include "local.h"
static _CONST int dname_len[7] = static _CONST int dname_len[7] =
@ -164,6 +269,53 @@ static _CONST char *_CONST mname[12] =
"May", "June", "July", "August", "September", "October", "November", "May", "June", "July", "August", "September", "October", "November",
"December"}; "December"};
/* Using the tm_year, tm_wday, and tm_yday components of TIM_P, return
-1, 0, or 1 as the adjustment to add to the year for the ISO week
numbering used in "%g%G%V", avoiding overflow. */
static int
_DEFUN (iso_year_adjust, (tim_p),
_CONST struct tm *tim_p)
{
/* Account for fact that tm_year==0 is year 1900. */
int leap = isleap (tim_p->tm_year + (YEAR_BASE
- (tim_p->tm_year < 0 ? 0 : 2000)));
/* Pack the yday, wday, and leap year into a single int since there are so
many disparate cases. */
#define PACK(yd, wd, lp) (((yd) << 4) + (wd << 1) + (lp))
switch (PACK (tim_p->tm_yday, tim_p->tm_wday, leap))
{
case PACK (0, 5, 0): /* Jan 1 is Fri, not leap. */
case PACK (0, 6, 0): /* Jan 1 is Sat, not leap. */
case PACK (0, 0, 0): /* Jan 1 is Sun, not leap. */
case PACK (0, 5, 1): /* Jan 1 is Fri, leap year. */
case PACK (0, 6, 1): /* Jan 1 is Sat, leap year. */
case PACK (0, 0, 1): /* Jan 1 is Sun, leap year. */
case PACK (1, 6, 0): /* Jan 2 is Sat, not leap. */
case PACK (1, 0, 0): /* Jan 2 is Sun, not leap. */
case PACK (1, 6, 1): /* Jan 2 is Sat, leap year. */
case PACK (1, 0, 1): /* Jan 2 is Sun, leap year. */
case PACK (2, 0, 0): /* Jan 3 is Sun, not leap. */
case PACK (2, 0, 1): /* Jan 3 is Sun, leap year. */
return -1; /* Belongs to last week of previous year. */
case PACK (362, 1, 0): /* Dec 29 is Mon, not leap. */
case PACK (363, 1, 1): /* Dec 29 is Mon, leap year. */
case PACK (363, 1, 0): /* Dec 30 is Mon, not leap. */
case PACK (363, 2, 0): /* Dec 30 is Tue, not leap. */
case PACK (364, 1, 1): /* Dec 30 is Mon, leap year. */
case PACK (364, 2, 1): /* Dec 30 is Tue, leap year. */
case PACK (364, 1, 0): /* Dec 31 is Mon, not leap. */
case PACK (364, 2, 0): /* Dec 31 is Tue, not leap. */
case PACK (364, 3, 0): /* Dec 31 is Wed, not leap. */
case PACK (365, 1, 1): /* Dec 31 is Mon, leap year. */
case PACK (365, 2, 1): /* Dec 31 is Tue, leap year. */
case PACK (365, 3, 1): /* Dec 31 is Wed, leap year. */
return 1; /* Belongs to first week of next year. */
}
return 0; /* Belongs to specified year. */
#undef PACK
}
size_t size_t
_DEFUN (strftime, (s, maxsize, format, tim_p), _DEFUN (strftime, (s, maxsize, format, tim_p),
char *s _AND char *s _AND
@ -188,8 +340,8 @@ _DEFUN (strftime, (s, maxsize, format, tim_p),
break; break;
format++; format++;
if (*format == 'E' || *format == 'O')
check_format: format++;
switch (*format) switch (*format)
{ {
@ -235,68 +387,140 @@ check_format:
} }
break; break;
case 'c': case 'c':
if (count < maxsize - 24) {
{ /* Length is not known because of %C%y, so recurse. */
for (i = 0; i < 3; i++) size_t adjust = strftime (&s[count], maxsize - count,
s[count++] = "%a %b %e %H:%M:%S %C%y", tim_p);
dname[tim_p->tm_wday][i]; if (adjust > 0)
s[count++] = ' '; count += adjust;
for (i = 0; i < 3; i++) else
s[count++] = return 0;
mname[tim_p->tm_mon][i]; }
break;
case 'C':
{
/* Examples of (tm_year + YEAR_BASE) that show how %Y == %C%y
with 32-bit int.
%Y %C %y
2147485547 21474855 47
10000 100 00
9999 99 99
0999 09 99
0099 00 99
0001 00 01
0000 00 00
-001 -0 01
-099 -0 99
-999 -9 99
-1000 -10 00
-10000 -100 00
-2147481748 -21474817 48
sprintf (&s[count], Be careful of both overflow and sign adjustment due to the
" %.2d %2.2d:%2.2d:%2.2d %.4d", asymmetric range of years.
tim_p->tm_mday, tim_p->tm_hour, */
tim_p->tm_min, int neg = tim_p->tm_year < -YEAR_BASE;
tim_p->tm_sec, 1900 + int century = tim_p->tm_year >= 0
tim_p->tm_year); ? tim_p->tm_year / 100 + YEAR_BASE / 100
count += 17; : abs (tim_p->tm_year + YEAR_BASE) / 100;
} count += snprintf (&s[count], maxsize - count, "%s%.*d",
else neg ? "-" : "", 2 - neg, century);
return 0; if (count >= maxsize)
return 0;
}
break; break;
case 'd': case 'd':
if (count < maxsize - 2)
{
sprintf (&s[count], "%.2d",
tim_p->tm_mday);
count += 2;
}
else
return 0;
break;
case 'E':
++format;
switch (*format)
{
case 'c':
case 'C':
case 'x':
case 'X':
case 'y':
case 'Y':
/* Ignore. */
goto check_format;
default:
--format;
}
break;
case 'e': case 'e':
if (count < maxsize - 2) if (count < maxsize - 2)
{ {
sprintf (&s[count], "%2d", sprintf (&s[count], *format == 'd' ? "%.2d" : "%2d",
tim_p->tm_mday); tim_p->tm_mday);
count += 2; count += 2;
} }
else else
return 0; return 0;
break; break;
case 'D':
case 'x':
/* %m/%d/%y */
if (count < maxsize - 8)
{
sprintf (&s[count], "%.2d/%.2d/%.2d",
tim_p->tm_mon + 1, tim_p->tm_mday,
(tim_p->tm_year % 100 + 100) % 100);
count += 8;
}
else
return 0;
break;
case 'F':
{
/* Length is not known because of %C%y, so recurse. */
size_t adjust = strftime (&s[count], maxsize - count,
"%C%y-%m-%d", tim_p);
if (adjust > 0)
count += adjust;
else
return 0;
}
break;
case 'g':
if (count < maxsize - 2)
{
/* Be careful of both overflow and negative years, thanks to
the asymmetric range of years. */
int adjust = iso_year_adjust (tim_p);
int year = tim_p->tm_year >= 0 ? tim_p->tm_year % 100
: abs (tim_p->tm_year + YEAR_BASE) % 100;
if (adjust < 0 && tim_p->tm_year <= -YEAR_BASE)
adjust = 1;
else if (adjust > 0 && tim_p->tm_year < -YEAR_BASE)
adjust = -1;
sprintf (&s[count], "%.2d",
((year + adjust) % 100 + 100) % 100);
count += 2;
}
else
return 0;
break;
case 'G':
{
/* See the comments for 'C' and 'Y'; this is a variable length
field. Although there is no requirement for a minimum number
of digits, we use 4 for consistency with 'Y'. */
int neg = tim_p->tm_year < -YEAR_BASE;
int adjust = iso_year_adjust (tim_p);
int century = tim_p->tm_year >= 0
? tim_p->tm_year / 100 + YEAR_BASE / 100
: abs (tim_p->tm_year + YEAR_BASE) / 100;
int year = tim_p->tm_year >= 0 ? tim_p->tm_year % 100
: abs (tim_p->tm_year + YEAR_BASE) % 100;
if (adjust < 0 && tim_p->tm_year <= -YEAR_BASE)
neg = adjust = 1;
else if (adjust > 0 && neg)
adjust = -1;
year += adjust;
if (year == -1)
{
year = 99;
--century;
}
else if (year == 100)
{
year = 0;
++century;
}
count += snprintf (&s[count], maxsize - count, "%s%.*d%.2d",
neg ? "-" : "", 2 - neg, century, year);
if (count >= maxsize)
return 0;
}
break;
case 'H': case 'H':
case 'k': case 'k':
if (count < maxsize - 2) if (count < maxsize - 2)
{ {
sprintf (&s[count], *format == 'k' ? "%2d" : "%2.2d", sprintf (&s[count], *format == 'k' ? "%2d" : "%.2d",
tim_p->tm_hour); tim_p->tm_hour);
count += 2; count += 2;
} }
@ -315,7 +539,7 @@ check_format:
} }
else else
{ {
sprintf (&s[count], (*format == 'I') ? "%.2d" : "%2d", sprintf (&s[count], *format == 'I' ? "%.2d" : "%2d",
tim_p->tm_hour % 12); tim_p->tm_hour % 12);
count += 2; count += 2;
} }
@ -346,36 +570,19 @@ check_format:
case 'M': case 'M':
if (count < maxsize - 2) if (count < maxsize - 2)
{ {
sprintf (&s[count], "%2.2d", sprintf (&s[count], "%.2d",
tim_p->tm_min); tim_p->tm_min);
count += 2; count += 2;
} }
else else
return 0; return 0;
break; break;
case 'O': case 'n':
++format; if (count < maxsize - 1)
switch (*format) s[count++] = '\n';
{ else
case 'd': return 0;
case 'e': break;
case 'H':
case 'I':
case 'm':
case 'M':
case 'S':
case 'u':
case 'U':
case 'V':
case 'w':
case 'W':
case 'y':
/* Ignore. */
goto check_format;
default:
--format;
}
break;
case 'p': case 'p':
if (count < maxsize - 2) if (count < maxsize - 2)
{ {
@ -404,11 +611,11 @@ check_format:
count += 2; count += 2;
} }
s[count++] = ':'; s[count++] = ':';
sprintf (&s[count], "%2.2d", sprintf (&s[count], "%.2d",
tim_p->tm_min); tim_p->tm_min);
count += 2; count += 2;
s[count++] = ':'; s[count++] = ':';
sprintf (&s[count], "%2.2d", sprintf (&s[count], "%.2d",
tim_p->tm_sec); tim_p->tm_sec);
count += 2; count += 2;
s[count++] = ' '; s[count++] = ' ';
@ -422,20 +629,57 @@ check_format:
else else
return 0; return 0;
break; break;
case 'R':
if (count < maxsize - 5)
{
sprintf (&s[count], "%.2d:%.2d", tim_p->tm_hour, tim_p->tm_min);
count += 5;
}
else
return 0;
break;
case 'S': case 'S':
if (count < maxsize - 2) if (count < maxsize - 2)
{ {
sprintf (&s[count], "%2.2d", sprintf (&s[count], "%.2d",
tim_p->tm_sec); tim_p->tm_sec);
count += 2; count += 2;
} }
else else
return 0; return 0;
break; break;
case 't':
if (count < maxsize - 1)
s[count++] = '\t';
else
return 0;
break;
case 'T':
case 'X':
if (count < maxsize - 8)
{
sprintf (&s[count], "%.2d:%.2d:%.2d", tim_p->tm_hour,
tim_p->tm_min, tim_p->tm_sec);
count += 8;
}
else
return 0;
break;
case 'u':
if (count < maxsize - 1)
{
if (tim_p->tm_wday == 0)
s[count++] = '7';
else
s[count++] = '0' + tim_p->tm_wday;
}
else
return 0;
break;
case 'U': case 'U':
if (count < maxsize - 2) if (count < maxsize - 2)
{ {
sprintf (&s[count], "%2.2d", sprintf (&s[count], "%.2d",
(tim_p->tm_yday + 7 - (tim_p->tm_yday + 7 -
tim_p->tm_wday) / 7); tim_p->tm_wday) / 7);
count += 2; count += 2;
@ -443,13 +687,32 @@ check_format:
else else
return 0; return 0;
break; break;
case 'V':
if (count < maxsize - 2)
{
int adjust = iso_year_adjust (tim_p);
int wday = (tim_p->tm_wday) ? tim_p->tm_wday - 1 : 6;
int week = (tim_p->tm_yday + 10 - wday) / 7;
if (adjust > 0)
week = 1;
else if (adjust < 0)
/* Previous year has 53 weeks if current year starts on
Fri, and also if current year starts on Sat and
previous year was leap year. */
week = 52 + (4 >= (wday - tim_p->tm_yday
- isleap (tim_p->tm_year
+ (YEAR_BASE - 1
- (tim_p->tm_year < 0
? 0 : 2000)))));
sprintf (&s[count], "%.2d", week);
count += 2;
}
else
return 0;
break;
case 'w': case 'w':
if (count < maxsize - 1) if (count < maxsize - 1)
{ s[count++] = '0' + tim_p->tm_wday;
sprintf (&s[count], "%1.1d",
tim_p->tm_wday);
count++;
}
else else
return 0; return 0;
break; break;
@ -457,43 +720,9 @@ check_format:
if (count < maxsize - 2) if (count < maxsize - 2)
{ {
int wday = (tim_p->tm_wday) ? tim_p->tm_wday - 1 : 6; int wday = (tim_p->tm_wday) ? tim_p->tm_wday - 1 : 6;
sprintf (&s[count], "%2.2d",
(tim_p->tm_yday + 7 -
wday) / 7);
count += 2;
}
else
return 0;
break;
case 'x':
if (count < maxsize - 8)
{
sprintf (&s[count], "%.2d", sprintf (&s[count], "%.2d",
tim_p->tm_mon + 1); (tim_p->tm_yday + 7 - wday) / 7);
count += 2; count += 2;
s[count++] = '/';
sprintf (&s[count], "%.2d",
tim_p->tm_mday);
count += 2;
s[count++] = '/';
/* The year could be greater than 100, so we need the value
modulo 100. The year could be negative, so we need to
correct for a possible negative remainder. */
sprintf (&s[count], "%2.2d",
(tim_p->tm_year % 100 + 100) % 100);
count += 2;
}
else
return 0;
break;
case 'X':
if (count < maxsize - 8)
{
sprintf (&s[count],
"%2.2d:%2.2d:%2.2d",
tim_p->tm_hour, tim_p->tm_min,
tim_p->tm_sec);
count += 8;
} }
else else
return 0; return 0;
@ -501,36 +730,57 @@ check_format:
case 'y': case 'y':
if (count < maxsize - 2) if (count < maxsize - 2)
{ {
/* The year could be greater than 100, so we need the value /* Be careful of both overflow and negative years, thanks to
modulo 100. The year could be negative, so we need to the asymmetric range of years. */
correct for a possible negative remainder. */ int year = tim_p->tm_year >= 0 ? tim_p->tm_year % 100
sprintf (&s[count], "%2.2d", : abs (tim_p->tm_year + YEAR_BASE) % 100;
(tim_p->tm_year % 100 + 100) % 100); sprintf (&s[count], "%.2d", year);
count += 2; count += 2;
} }
else else
return 0; return 0;
break; break;
case 'Y': case 'Y':
if (count < maxsize - 4) {
{ /* Length is not known because of %C%y, so recurse. */
sprintf (&s[count], "%.4d", size_t adjust = strftime (&s[count], maxsize - count,
1900 + tim_p->tm_year); "%C%y", tim_p);
count += 4; if (adjust > 0)
} count += adjust;
else else
return 0; return 0;
}
break; break;
case 'z':
if (tim_p->tm_isdst >= 0)
{
if (count < maxsize - 5)
{
int offset;
TZ_LOCK;
/* The sign of this is exactly opposite the envvar TZ. We
could directly use the global _timezone for tm_isdst==0,
but have to use __tzrule for daylight savings. */
offset = -__tzrule[tim_p->tm_isdst > 0].offset;
TZ_UNLOCK;
sprintf (&s[count], "%+03ld%.2d", offset / SECSPERHOUR,
abs (offset / SECSPERMIN) % 60);
count += 5;
}
else
return 0;
}
break;
case 'Z': case 'Z':
if (tim_p->tm_isdst >= 0) if (tim_p->tm_isdst >= 0)
{ {
int size; int size;
TZ_LOCK; TZ_LOCK;
size = strlen(_tzname[tim_p->tm_isdst]); size = strlen(_tzname[tim_p->tm_isdst > 0]);
for (i = 0; i < size; i++) for (i = 0; i < size; i++)
{ {
if (count < maxsize - 1) if (count < maxsize - 1)
s[count++] = _tzname[tim_p->tm_isdst][i]; s[count++] = _tzname[tim_p->tm_isdst > 0][i];
else else
{ {
TZ_UNLOCK; TZ_UNLOCK;
@ -552,7 +802,8 @@ check_format:
else else
break; break;
} }
s[count] = '\0'; if (maxsize)
s[count] = '\0';
return count; return count;
} }

16
newlib/libc/time/time.tex
View File

@ -18,28 +18,28 @@ the following fields:
@table @code @table @code
@item tm_sec @item tm_sec
Seconds. Seconds, between 0 and 60 inclusive (60 allows for leap seconds).
@item tm_min @item tm_min
Minutes. Minutes, between 0 and 59 inclusive.
@item tm_hour @item tm_hour
Hours. Hours, between 0 and 23 inclusive.
@item tm_mday @item tm_mday
Day. Day of the month, between 1 and 31 inclusive.
@item tm_mon @item tm_mon
Month. Month, between 0 (January) and 11 (December).
@item tm_year @item tm_year
Year (since 1900). Year (since 1900), can be negative for earlier years.
@item tm_wday @item tm_wday
Day of week: the number of days since Sunday. Day of week, between 0 (Sunday) and 6 (Saturday).
@item tm_yday @item tm_yday
Number of days elapsed since last January 1. Number of days elapsed since last January 1, between 0 and 365 inclusive.
@item tm_isdst @item tm_isdst
Daylight Savings Time flag: positive means DST in effect, zero means DST Daylight Savings Time flag: positive means DST in effect, zero means DST