src/lib/w32/strptime.c

Go to the documentation of this file.

#include "misc.h"

/*
 * Ported from NetBSD to Windows by Ron Koenderink, 2007
 */

/*      $NetBSD: strptime.c,v 1.25 2005/11/29 03:12:00 christos Exp $   */

/*-
 * Copyright (c) 1997, 1998, 2005 The NetBSD Foundation, Inc.
 * All rights reserved.
 *
 * This code was contributed to The NetBSD Foundation by Klaus Klein.
 * Heavily optimised by David Laight
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. All advertising materials mentioning features or use of this software
 *    must display the following acknowledgement:
 *        This product includes software developed by the NetBSD
 *        Foundation, Inc. and its contributors.
 * 4. Neither the name of The NetBSD Foundation nor the names of its
 *    contributors may be used to endorse or promote products derived
 *    from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
 * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 * POSSIBILITY OF SUCH DAMAGE.
 */

#if !defined(_WIN32)
#include <sys/cdefs.h>
#endif

#if defined(LIBC_SCCS) && !defined(lint)
__RCSID("$NetBSD: strptime.c,v 1.25 2005/11/29 03:12:00 christos Exp $");
#endif

#if !defined(_WIN32)
#include "namespace.h"
#include <sys/localedef.h>
#else
typedef unsigned char u_char;
typedef unsigned int uint;
#endif
#include <ctype.h>
#include <locale.h>
#include <string.h>
#include <time.h>
#if !defined(_WIN32)
#include <tzfile.h>
#endif

#ifdef __weak_alias
__weak_alias(strptime,_strptime)
#endif

#if !defined(_WIN32)
#define _ctloc(x)               (_CurrentTimeLocale->x)
#else
#define _ctloc(x)   (x)
const char *abday[] = {
        "Sun", "Mon", "Tue", "Wed",
        "Thu", "Fri", "Sat"
};
const char *day[] = {
        "Sunday", "Monday", "Tuesday", "Wednesday",
        "Thursday", "Friday", "Saturday"
};
const char *abmon[] =   {
        "Jan", "Feb", "Mar", "Apr", "May", "Jun",
        "Jul", "Aug", "Sep", "Oct", "Nov", "Dec"
};
const char *mon[] = {
        "January", "February", "March", "April", "May", "June",
        "July", "August", "September", "October", "November", "December"
};
const char *am_pm[] = {
        "AM", "PM"
};
char *d_t_fmt = "%a %Ef %T %Y";
char *t_fmt_ampm = "%I:%M:%S %p";
char *t_fmt = "%H:%M:%S";
char *d_fmt = "%m/%d/%y";
#define TM_YEAR_BASE 1900
#define __UNCONST(x) ((void *)(((const char *)(x) - (const char *)0) + (char *)0))

#endif
/*
 * We do not implement alternate representations. However, we always
 * check whether a given modifier is allowed for a certain conversion.
 */
#define ALT_E                   0x01
#define ALT_O                   0x02
#define LEGAL_ALT(x)            { if (alt_format & ~(x)) return NULL; }


static const u_char *conv_num(const unsigned char *, int *, uint, uint);
static const u_char *find_string(const u_char *, int *, const char * const *,
        const char * const *, int);


char *
strptime(const char *buf, const char *fmt, struct tm *tm)
{
        unsigned char c;
        const unsigned char *bp;
        int alt_format, i, split_year = 0;
        const char *new_fmt;

        bp = (const u_char *)buf;

        while (bp != NULL && (c = *fmt++) != '\0') {
                /* Clear `alternate' modifier prior to new conversion. */
                alt_format = 0;
                i = 0;

                /* Eat up white-space. */
                if (isspace(c)) {
                        while (isspace(*bp))
                                bp++;
                        continue;
                }

                if (c != '%')
                        goto literal;


again:          switch (c = *fmt++) {
                case '%':       /* "%%" is converted to "%". */
literal:
                        if (c != *bp++)
                                return NULL;
                        LEGAL_ALT(0);
                        continue;

                /*
                 * "Alternative" modifiers. Just set the appropriate flag
                 * and start over again.
                 */
                case 'E':       /* "%E?" alternative conversion modifier. */
                        LEGAL_ALT(0);
                        alt_format |= ALT_E;
                        goto again;

                case 'O':       /* "%O?" alternative conversion modifier. */
                        LEGAL_ALT(0);
                        alt_format |= ALT_O;
                        goto again;

                /*
                 * "Complex" conversion rules, implemented through recursion.
                 */
                case 'c':       /* Date and time, using the locale's format. */
                        new_fmt = _ctloc(d_t_fmt);
                        goto recurse;

                case 'D':       /* The date as "%m/%d/%y". */
                        new_fmt = "%m/%d/%y";
                        LEGAL_ALT(0);
                        goto recurse;

                case 'R':       /* The time as "%H:%M". */
                        new_fmt = "%H:%M";
                        LEGAL_ALT(0);
                        goto recurse;

                case 'r':       /* The time in 12-hour clock representation. */
                        new_fmt =_ctloc(t_fmt_ampm);
                        LEGAL_ALT(0);
                        goto recurse;

                case 'T':       /* The time as "%H:%M:%S". */
                        new_fmt = "%H:%M:%S";
                        LEGAL_ALT(0);
                        goto recurse;

                case 'X':       /* The time, using the locale's format. */
                        new_fmt =_ctloc(t_fmt);
                        goto recurse;

                case 'x':       /* The date, using the locale's format. */
                        new_fmt =_ctloc(d_fmt);
                    recurse:
                        bp = (const u_char *)strptime((const char *)bp,
                                                            new_fmt, tm);
                        LEGAL_ALT(ALT_E);
                        continue;

                /*
                 * "Elementary" conversion rules.
                 */
                case 'A':       /* The day of week, using the locale's form. */
                case 'a':
                        bp = find_string(bp, &tm->tm_wday, _ctloc(day),
                                        _ctloc(abday), 7);
                        LEGAL_ALT(0);
                        continue;

                case 'B':       /* The month, using the locale's form. */
                case 'b':
                case 'h':
                        bp = find_string(bp, &tm->tm_mon, _ctloc(mon),
                                        _ctloc(abmon), 12);
                        LEGAL_ALT(0);
                        continue;

                case 'C':       /* The century number. */
                        i = 20;
                        bp = conv_num(bp, &i, 0, 99);

                        i = i * 100 - TM_YEAR_BASE;
                        if (split_year)
                                i += tm->tm_year % 100;
                        split_year = 1;
                        tm->tm_year = i;
                        LEGAL_ALT(ALT_E);
                        continue;

                case 'd':       /* The day of month. */
                case 'e':
                        bp = conv_num(bp, &tm->tm_mday, 1, 31);
                        LEGAL_ALT(ALT_O);
                        continue;

                case 'k':       /* The hour (24-hour clock representation). */
                        LEGAL_ALT(0);
                        /* FALLTHROUGH */
                case 'H':
                        bp = conv_num(bp, &tm->tm_hour, 0, 23);
                        LEGAL_ALT(ALT_O);
                        continue;

                case 'l':       /* The hour (12-hour clock representation). */
                        LEGAL_ALT(0);
                        /* FALLTHROUGH */
                case 'I':
                        bp = conv_num(bp, &tm->tm_hour, 1, 12);
                        if (tm->tm_hour == 12)
                                tm->tm_hour = 0;
                        LEGAL_ALT(ALT_O);
                        continue;

                case 'j':       /* The day of year. */
                        i = 1;
                        bp = conv_num(bp, &i, 1, 366);
                        tm->tm_yday = i - 1;
                        LEGAL_ALT(0);
                        continue;

                case 'M':       /* The minute. */
                        bp = conv_num(bp, &tm->tm_min, 0, 59);
                        LEGAL_ALT(ALT_O);
                        continue;

                case 'm':       /* The month. */
                        i = 1;
                        bp = conv_num(bp, &i, 1, 12);
                        tm->tm_mon = i - 1;
                        LEGAL_ALT(ALT_O);
                        continue;

                case 'p':       /* The locale's equivalent of AM/PM. */
                        bp = find_string(bp, &i, _ctloc(am_pm), NULL, 2);
                        if (tm->tm_hour > 11)
                                return NULL;
                        tm->tm_hour += i * 12;
                        LEGAL_ALT(0);
                        continue;

                case 'S':       /* The seconds. */
                        bp = conv_num(bp, &tm->tm_sec, 0, 61);
                        LEGAL_ALT(ALT_O);
                        continue;

                case 'U':       /* The week of year, beginning on sunday. */
                case 'W':       /* The week of year, beginning on monday. */
                        /*
                         * XXX This is bogus, as we can not assume any valid
                         * information present in the tm structure at this
                         * point to calculate a real value, so just check the
                         * range for now.
                         */
                         bp = conv_num(bp, &i, 0, 53);
                         LEGAL_ALT(ALT_O);
                         continue;

                case 'w':       /* The day of week, beginning on sunday. */
                        bp = conv_num(bp, &tm->tm_wday, 0, 6);
                        LEGAL_ALT(ALT_O);
                        continue;

                case 'Y':       /* The year. */
                        i = TM_YEAR_BASE;       /* just for data sanity... */
                        bp = conv_num(bp, &i, 0, 9999);
                        tm->tm_year = i - TM_YEAR_BASE;
                        LEGAL_ALT(ALT_E);
                        continue;

                case 'y':       /* The year within 100 years of the epoch. */
                        /* LEGAL_ALT(ALT_E | ALT_O); */
                        bp = conv_num(bp, &i, 0, 99);

                        if (split_year)
                                /* preserve century */
                                i += (tm->tm_year / 100) * 100;
                        else {
                                split_year = 1;
                                if (i <= 68)
                                        i = i + 2000 - TM_YEAR_BASE;
                                else
                                        i = i + 1900 - TM_YEAR_BASE;
                        }
                        tm->tm_year = i;
                        continue;

                /*
                 * Miscellaneous conversions.
                 */
                case 'n':       /* Any kind of white-space. */
                case 't':
                        while (isspace(*bp))
                                bp++;
                        LEGAL_ALT(0);
                        continue;


                default:        /* Unknown/unsupported conversion. */
                        return NULL;
                }
        }

        return __UNCONST(bp);
}


static const u_char *
conv_num(const unsigned char *buf, int *dest, uint llim, uint ulim)
{
        uint result = 0;
        unsigned char ch;

        /* The limit also determines the number of valid digits. */
        uint rulim = ulim;

        ch = *buf;
        if (ch < '0' || ch > '9')
                return NULL;

        do {
                result *= 10;
                result += ch - '0';
                rulim /= 10;
                ch = *++buf;
        } while ((result * 10 <= ulim) && rulim && ch >= '0' && ch <= '9');

        if (result < llim || result > ulim)
                return NULL;

        *dest = result;
        return buf;
}

static const u_char *
find_string(const u_char *bp, int *tgt, const char * const *n1,
                const char * const *n2, int c)
{
        int i;
        unsigned int len;

        /* check full name - then abbreviated ones */
        for (; n1 != NULL; n1 = n2, n2 = NULL) {
                for (i = 0; i < c; i++, n1++) {
                        len = strlen(*n1);
                        if (strncasecmp(*n1, (const char *)bp, len) == 0) {
                                *tgt = i;
                                return bp + len;
                        }
                }
        }

        /* Nothing matched */
        return NULL;
}

---