port/locale/strptime.c

/*
 * Copyright (c) 2014 Gary Mills
 * Copyright 2014 Garrett D'Amore <garrett@damore.org>
 * Copyright 2011, Nexenta Systems, Inc.  All rights reserved.
 * Copyright (c) 1994 Powerdog Industries.  All rights reserved.
 *
 * 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.
 *
 * THIS SOFTWARE IS PROVIDED BY POWERDOG INDUSTRIES ``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 POWERDOG INDUSTRIES 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.
 *
 * The views and conclusions contained in the software and documentation
 * are those of the authors and should not be interpreted as representing
 * official policies, either expressed or implied, of Powerdog Industries.
 */

#include "lint.h"
#include <time.h>
#include <ctype.h>
#include <errno.h>
#include <stdlib.h>
#include <string.h>
#include <pthread.h>
#include <alloca.h>
#include <locale.h>
#include "timelocal.h"
#include "localeimpl.h"

#define asizeof(a)  (sizeof (a) / sizeof ((a)[0]))

#define F_GMT       (1 << 0)
#define F_RECURSE   (1 << 2)

static char *
__strptime(const char *_RESTRICT_KYWD buf, const char *_RESTRICT_KYWD fmt,
    struct tm *_RESTRICT_KYWD tm, int *_RESTRICT_KYWD flagsp,
    locale_t _RESTRICT_KYWD loc)
{
    char    c;
    const char *ptr;
    int i, len, recurse = 0;
    int Ealternative, Oalternative;
    const struct lc_time *tptr = loc->time;

    if (*flagsp & F_RECURSE)
        recurse = 1;
    *flagsp |= F_RECURSE;

    ptr = fmt;
    while (*ptr != 0) {
        if (*buf == 0)
            break;

        c = *ptr++;

        if (c != '%') {
            if (isspace(c))
                while (isspace(*buf))
                    buf++;
            else if (c != *buf++)
                return (NULL);
            continue;
        }

        Ealternative = 0;
        Oalternative = 0;
label:
        c = *ptr++;
        switch (c) {
        case 0:
        case '%':
            if (*buf++ != '%')
                return (NULL);
            break;

        case '+':
            buf = __strptime(buf, tptr->date_fmt, tm, flagsp, loc);
            if (buf == NULL)
                return (NULL);
            break;

        case 'C':
            if (!isdigit(*buf))
                return (NULL);

            /* XXX This will break for 3-digit centuries. */
            len = 2;
            for (i = 0; len && isdigit(*buf); buf++) {
                i *= 10;
                i += *buf - '0';
                len--;
            }
            if (i < 19)
                return (NULL);

            tm->tm_year = i * 100 - 1900;
            break;

        case 'c':
            buf = __strptime(buf, tptr->c_fmt, tm, flagsp, loc);
            if (buf == NULL)
                return (NULL);
            break;

        case 'D':
            buf = __strptime(buf, "%m/%d/%y", tm, flagsp, loc);
            if (buf == NULL)
                return (NULL);
            break;

        case 'E':
            if (Ealternative || Oalternative)
                break;
            Ealternative++;
            goto label;

        case 'O':
            if (Ealternative || Oalternative)
                break;
            Oalternative++;
            goto label;

        case 'F':
            buf = __strptime(buf, "%Y-%m-%d", tm, flagsp, loc);
            if (buf == NULL)
                return (NULL);
            break;

        case 'R':
            buf = __strptime(buf, "%H:%M", tm, flagsp, loc);
            if (buf == NULL)
                return (NULL);
            break;

        case 'r':
            buf = __strptime(buf, tptr->ampm_fmt, tm, flagsp, loc);
            if (buf == NULL)
                return (NULL);
            break;

        case 'T':
            buf = __strptime(buf, "%H:%M:%S", tm, flagsp, loc);
            if (buf == NULL)
                return (NULL);
            break;

        case 'X':
            buf = __strptime(buf, tptr->X_fmt, tm, flagsp, loc);
            if (buf == NULL)
                return (NULL);
            break;

        case 'x':
            buf = __strptime(buf, tptr->x_fmt, tm, flagsp, loc);
            if (buf == NULL)
                return (NULL);
            break;

        case 'j':
            if (!isdigit(*buf))
                return (NULL);

            len = 3;
            for (i = 0; len && isdigit(*buf); buf++) {
                i *= 10;
                i += *buf - '0';
                len--;
            }
            if (i < 1 || i > 366)
                return (NULL);

            tm->tm_yday = i - 1;
            break;

        case 'M':
        case 'S':
            if (*buf == 0 || isspace(*buf))
                break;

            if (!isdigit(*buf))
                return (NULL);

            len = 2;
            for (i = 0; len && isdigit(*buf); buf++) {
                i *= 10;
                i += *buf - '0';
                len--;
            }

            if (c == 'M') {
                if (i > 59)
                    return (NULL);
                tm->tm_min = i;
            } else {
                if (i > 60)
                    return (NULL);
                tm->tm_sec = i;
            }

            break;

        case 'H':
        case 'I':
        case 'k':
        case 'l':
            /*
             * Of these, %l is the only specifier explicitly
             * documented as not being zero-padded.  However,
             * there is no harm in allowing zero-padding.
             *
             * XXX The %l specifier may gobble one too many
             * digits if used incorrectly.
             */
            if (!isdigit(*buf))
                return (NULL);

            len = 2;
            for (i = 0; len && isdigit(*buf); buf++) {
                i *= 10;
                i += *buf - '0';
                len--;
            }
            if (c == 'H' || c == 'k') {
                if (i > 23)
                    return (NULL);
            } else if (i > 12)
                return (NULL);

            tm->tm_hour = i;

            break;

        case 'p':
            /*
             * XXX This is bogus if parsed before hour-related
             * specifiers.
             */
            len = strlen(tptr->am);
            if (strncasecmp(buf, tptr->am, len) == 0) {
                if (tm->tm_hour > 12)
                    return (NULL);
                if (tm->tm_hour == 12)
                    tm->tm_hour = 0;
                buf += len;
                break;
            }

            len = strlen(tptr->pm);
            if (strncasecmp(buf, tptr->pm, len) == 0) {
                if (tm->tm_hour > 12)
                    return (NULL);
                if (tm->tm_hour != 12)
                    tm->tm_hour += 12;
                buf += len;
                break;
            }

            return (NULL);

        case 'A':
        case 'a':
            for (i = 0; i < asizeof(tptr->weekday); i++) {
                len = strlen(tptr->weekday[i]);
                if (strncasecmp(buf, tptr->weekday[i], len) ==
                    0)
                    break;
                len = strlen(tptr->wday[i]);
                if (strncasecmp(buf, tptr->wday[i], len) == 0)
                    break;
            }
            if (i == asizeof(tptr->weekday))
                return (NULL);

            tm->tm_wday = i;
            buf += len;
            break;

        case 'U':
        case 'W':
            /*
             * 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.
             */
            if (!isdigit(*buf))
                return (NULL);

            len = 2;
            for (i = 0; len && isdigit(*buf); buf++) {
                i *= 10;
                i += *buf - '0';
                len--;
            }
            if (i > 53)
                return (NULL);

            break;

        case 'w':
            if (!isdigit(*buf))
                return (NULL);

            i = *buf - '0';
            if (i > 6)
                return (NULL);

            tm->tm_wday = i;

            break;

        case 'd':
        case 'e':
            /*
             * The %e format has a space before single digits
             * which we need to skip.
             */
            if (isspace(*buf))
                buf++;
            /*
             * The %e specifier is explicitly documented as not
             * being zero-padded but there is no harm in allowing
             * such padding.
             *
             * XXX The %e specifier may gobble one too many
             * digits if used incorrectly.
             */
            if (!isdigit(*buf))
                return (NULL);

            len = 2;
            for (i = 0; len && isdigit(*buf); buf++) {
                i *= 10;
                i += *buf - '0';
                len--;
            }
            if (i > 31)
                return (NULL);

            tm->tm_mday = i;

            break;

        case 'B':
        case 'b':
        case 'h':
            for (i = 0; i < asizeof(tptr->month); i++) {
                len = strlen(tptr->month[i]);
                if (strncasecmp(buf, tptr->month[i], len) == 0)
                    break;
            }
            /*
             * Try the abbreviated month name if the full name
             * wasn't found.
             */
            if (i == asizeof(tptr->month)) {
                for (i = 0; i < asizeof(tptr->month); i++) {
                    len = strlen(tptr->mon[i]);
                    if (strncasecmp(buf, tptr->mon[i],
                        len) == 0)
                        break;
                }
            }
            if (i == asizeof(tptr->month))
                return (NULL);

            tm->tm_mon = i;
            buf += len;
            break;

        case 'm':
            if (!isdigit(*buf))
                return (NULL);

            len = 2;
            for (i = 0; len && isdigit(*buf); buf++) {
                i *= 10;
                i += *buf - '0';
                len--;
            }
            if (i < 1 || i > 12)
                return (NULL);

            tm->tm_mon = i - 1;

            break;

        case 's':
            {
            char *cp;
            int sverrno;
            time_t t;

            sverrno = errno;
            errno = 0;
            t = strtol(buf, &cp, 10);
            if (errno == ERANGE) {
                errno = sverrno;
                return (NULL);
            }
            errno = sverrno;
            buf = cp;
            (void) gmtime_r(&t, tm);
            *flagsp |= F_GMT;
            }
            break;

        case 'Y':
        case 'y':
            if (*buf == NULL || isspace(*buf))
                break;

            if (!isdigit(*buf))
                return (NULL);

            len = (c == 'Y') ? 4 : 2;
            for (i = 0; len && isdigit(*buf); buf++) {
                i *= 10;
                i += *buf - '0';
                len--;
            }
            if (c == 'Y')
                i -= 1900;
            if (c == 'y' && i < 69)
                i += 100;
            if (i < 0)
                return (NULL);

            tm->tm_year = i;

            break;

        case 'Z':
            {
            const char *cp = buf;
            char *zonestr;

            while (isupper(*cp))
                ++cp;
            if (cp - buf) {
                zonestr = alloca(cp - buf + 1);
                (void) strncpy(zonestr, buf, cp - buf);
                zonestr[cp - buf] = '\0';
                tzset();
                if (strcmp(zonestr, "GMT") == 0) {
                    *flagsp |= F_GMT;
                } else if (0 == strcmp(zonestr, tzname[0])) {
                    tm->tm_isdst = 0;
                } else if (0 == strcmp(zonestr, tzname[1])) {
                    tm->tm_isdst = 1;
                } else {
                    return (NULL);
                }
                buf += cp - buf;
            }
            }
            break;

        case 'z':
            {
            int sign = 1;

            if (*buf != '+') {
                if (*buf == '-')
                    sign = -1;
                else
                    return (NULL);
            }
            buf++;
            i = 0;
            for (len = 4; len > 0; len--) {
                if (!isdigit(*buf))
                    return (NULL);
                i *= 10;
                i += *buf - '0';
                buf++;
            }

            tm->tm_hour -= sign * (i / 100);
            tm->tm_min -= sign * (i % 100);
            *flagsp |= F_GMT;
            }
            break;
        case 'n':
        case 't':
            while (isspace(*buf))
                buf++;
            break;
        }
    }

    if (!recurse) {
        if (buf && (*flagsp & F_GMT)) {
            time_t t = timegm(tm);
            (void) localtime_r(&t, tm);
        }
    }

    return ((char *)buf);
}

char *
strptime(const char *_RESTRICT_KYWD buf, const char *_RESTRICT_KYWD fmt,
    struct tm *_RESTRICT_KYWD tm)
{
    int flags = 0;

    (void) memset(tm, 0, sizeof (*tm));

    return (__strptime(buf, fmt, tm, &flags, uselocale(NULL)));
}

/*
 * This is used by Solaris, and is a variant that does not clear the
 * incoming tm.  It is triggered by -D_STRPTIME_DONTZERO.
 */
char *
__strptime_dontzero(const char *_RESTRICT_KYWD buf,
    const char *_RESTRICT_KYWD fmt, struct tm *_RESTRICT_KYWD tm)
{
    int flags = 0;

    return (__strptime(buf, fmt, tm, &flags, uselocale(NULL)));
}

/*
 * strptime_l is an extension that seems natural, and indeed, MacOS X
 * includes it within their <xlocale.h> and it is part of GNU libc as well.
 * For now we restrict it to the cases where strict namespaces are not
 * included.  We expect to see it in a future version of POSIX.  locale_t is
 * not a restrict, since the spec for it doesn't assume its a pointer.  We
 * therefore pass it analagously to the way strftime_l is specified.
 *
 * We are not providing a non-zeroing version at this time.
 */
char *
strptime_l(const char *_RESTRICT_KYWD buf, const char *_RESTRICT_KYWD fmt,
    struct tm *_RESTRICT_KYWD tm, locale_t loc)
{
    int flags =  0;

    (void) memset(tm, 0, sizeof (*tm));

    return (__strptime(buf, fmt, tm, &flags, loc));
}