glibc/time/strptime.c

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/* strptime - Convert a string representation of time to a time value.
Copyright (C) 1996 Free Software Foundation, Inc.
This file is part of the GNU C Library.
Contributed by Ulrich Drepper <drepper@cygnus.com>, 1996.
The GNU C Library is free software; you can redistribute it and/or
modify it under the terms of the GNU Library General Public License as
published by the Free Software Foundation; either version 2 of the
License, or (at your option) any later version.
The GNU C Library 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
Library General Public License for more details.
You should have received a copy of the GNU Library General Public
License along with the GNU C Library; see the file COPYING.LIB. If
not, write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
Boston, MA 02111-1307, USA. */
#include <ctype.h>
#include <langinfo.h>
#include <limits.h>
#include <string.h>
#include <time.h>
#include "../locale/localeinfo.h"
#define match_char(ch1, ch2) if (ch1 != ch2) return NULL
#define match_string(cs1, s2) \
({ size_t len = strlen (cs1); \
int result = strncasecmp (cs1, s2, len) == 0; \
if (result) s2 += len; \
result; })
/* We intentionally do not use isdigit() for testing because this will
lead to problems with the wide character version. */
#define get_number(from, to) \
do { \
val = 0; \
if (*rp < '0' || *rp > '9') \
return NULL; \
do { \
val *= 10; \
val += *rp++ - '0'; \
} while (val * 10 <= to && *rp >= '0' && *rp <= '9'); \
if (val < from || val > to) \
return NULL; \
} while (0)
#define get_alt_number(from, to) \
do { \
const char *alts = _NL_CURRENT (LC_TIME, ALT_DIGITS); \
val = 0; \
while (*alts != '\0') \
{ \
size_t len = strlen (alts); \
if (strncasecmp (alts, rp, len) == 0) \
break; \
alts = strchr (alts, '\0') + 1; \
++val; \
} \
if (*alts == '\0') \
return NULL; \
} while (0)
#define recursive(new_fmt) \
do { \
if (*new_fmt == '\0') \
return NULL; \
rp = strptime (rp, new_fmt, tm); \
if (rp == NULL) \
return NULL; \
} while (0)
char *
strptime (const char *buf, const char *format, struct tm *tm)
{
const char *rp;
const char *fmt;
int cnt;
size_t val;
int have_I, is_pm;
rp = buf;
fmt = format;
have_I = is_pm = 0;
while (*fmt != '\0')
{
/* A white space in the format string matches 0 more or white
space in the input string. */
if (isspace (*fmt))
{
while (isspace (*rp))
++rp;
++fmt;
continue;
}
/* Any character but `%' must be matched by the same character
in the iput string. */
if (*fmt != '%')
{
match_char (*fmt++, *rp++);
continue;
}
++fmt;
switch (*fmt++)
{
case '%':
/* Match the `%' character itself. */
match_char ('%', *rp++);
break;
case 'a':
case 'A':
/* Match day of week. */
for (cnt = 0; cnt < 7; ++cnt)
{
if (match_string (_NL_CURRENT (LC_TIME, ABDAY_1 + cnt), rp))
break;
if (match_string (_NL_CURRENT (LC_TIME, DAY_1 + cnt), rp))
break;
}
if (cnt == 7)
/* Does not match a weekday name. */
return NULL;
tm->tm_wday = cnt;
break;
case 'b':
case 'B':
case 'h':
/* Match month name. */
for (cnt = 0; cnt < 12; ++cnt)
{
if (match_string (_NL_CURRENT (LC_TIME, ABMON_1 + cnt), rp))
break;
if (match_string (_NL_CURRENT (LC_TIME, MON_1 + cnt), rp))
break;
}
if (cnt == 12)
/* Does not match a month name. */
return NULL;
tm->tm_mon = cnt;
break;
case 'c':
/* Match locale's date and time format. */
recursive (_NL_CURRENT (LC_TIME, D_T_FMT));
break;
case 'C':
/* Match century number. */
get_number (0, 99);
/* We don't need the number. */
break;
case 'd':
case 'e':
/* Match day of month. */
get_number (1, 31);
tm->tm_mday = val;
break;
case 'D':
/* Match standard day format. */
recursive ("%m/%d/%y");
break;
case 'H':
/* Match hour in 24-hour clock. */
get_number (0, 23);
tm->tm_hour = val;
have_I = 0;
break;
case 'I':
/* Match hour in 12-hour clock. */
get_number (1, 12);
tm->tm_hour = val - 1;
have_I = 1;
break;
case 'j':
/* Match day number of year. */
get_number (1, 366);
tm->tm_yday = val - 1;
break;
case 'm':
/* Match number of month. */
get_number (1, 12);
tm->tm_mon = val - 1;
break;
case 'M':
/* Match minute. */
get_number (0, 59);
tm->tm_min = val;
break;
case 'n':
case 't':
/* Match any white space. */
while (isspace (*rp))
++rp;
break;
case 'p':
/* Match locale's equivalent of AM/PM. */
if (match_string (_NL_CURRENT (LC_TIME, AM_STR), rp))
break;
if (match_string (_NL_CURRENT (LC_TIME, PM_STR), rp))
{
is_pm = 1;
break;
}
return NULL;
case 'r':
recursive (_NL_CURRENT (LC_TIME, T_FMT_AMPM));
break;
case 'R':
recursive ("%H:%M");
break;
case 'S':
get_number (0, 61);
tm->tm_sec = val;
break;
case 'T':
recursive ("%H:%M:%S");
break;
case 'U':
case 'V':
case 'W':
get_number (0, 53);
/* XXX This cannot determine any field in TM. */
break;
case 'w':
/* Match number of weekday. */
get_number (0, 6);
tm->tm_wday = val;
break;
case 'x':
recursive (_NL_CURRENT (LC_TIME, D_FMT));
break;
case 'X':
recursive (_NL_CURRENT (LC_TIME, T_FMT));
break;
case 'y':
/* Match year within century. */
get_number (0, 99);
tm->tm_year = val;
break;
case 'Y':
/* Match year including century number. */
get_number (0, INT_MAX);
tm->tm_year = val - (val >= 2000 ? 2000 : 1900);
break;
case 'Z':
/* XXX How to handle this? */
break;
case 'E':
switch (*fmt++)
{
case 'c':
/* Match locale's alternate date and time format. */
recursive (_NL_CURRENT (LC_TIME, ERA_D_T_FMT));
break;
case 'C':
case 'y':
case 'Y':
/* Match name of base year in locale's alternate
representation. */
/* XXX This is currently not implemented. It should
use the value _NL_CURRENT (LC_TIME, ERA) but POSIX
leaves this implementation defined and we haven't
figured out how to do it yet. */
break;
case 'x':
recursive (_NL_CURRENT (LC_TIME, ERA_D_FMT));
break;
case 'X':
recursive (_NL_CURRENT (LC_TIME, ERA_T_FMT));
break;
default:
return NULL;
}
break;
case 'O':
switch (*fmt++)
{
case 'd':
case 'e':
/* Match day of month using alternate numeric symbols. */
get_alt_number (1, 31);
tm->tm_mday = val;
break;
case 'H':
/* Match hour in 24-hour clock using alternate numeric
symbols. */
get_alt_number (0, 23);
tm->tm_hour = val;
have_I = 0;
break;
case 'I':
/* Match hour in 12-hour clock using alternate numeric
symbols. */
get_alt_number (1, 12);
tm->tm_hour = val - 1;
have_I = 1;
break;
case 'm':
/* Match month using alternate numeric symbols. */
get_alt_number (1, 12);
tm->tm_mon = val - 1;
break;
case 'M':
/* Match minutes using alternate numeric symbols. */
get_alt_number (0, 59);
tm->tm_min = val;
break;
case 'S':
/* Match seconds using alternate numeric symbols. */
get_alt_number (0, 61);
tm->tm_sec = val;
break;
case 'U':
case 'V':
case 'W':
get_alt_number (0, 53);
/* XXX This cannot determine any field in TM. */
break;
case 'w':
/* Match number of weekday using alternate numeric symbols. */
get_alt_number (0, 6);
tm->tm_wday = val;
break;
case 'y':
/* Match year within century using alternate numeric symbols. */
get_alt_number (0, 99);
break;
default:
return NULL;
}
break;
default:
return NULL;
}
}
if (have_I && is_pm)
tm->tm_hour += 12;
return (char *) rp;
}