usr/src/sbin/dump/unctime.c

/*-
 * Copyright (c) 1980 The Regents of the University of California.
 * All rights reserved.
 *
 * %sccs.include.redist.c%
 */

#ifndef lint
static char sccsid[] = "@(#)unctime.c   5.7 (Berkeley) %G%";
#endif /* not lint */

#include <sys/types.h>

#include <stdio.h>
#include <time.h>
#ifdef __STDC__
#include <stdlib.h>
#include <string.h>
#endif

#ifndef __P
#include <sys/cdefs.h>
#endif

/*
 * Convert a ctime(3) format string into a system format date.
 * Return the date thus calculated.
 *
 * Return -1 if the string is not in ctime format.
 */

/*
 * Offsets into the ctime string to various parts.
 */

#define E_MONTH         4
#define E_DAY           8
#define E_HOUR          11
#define E_MINUTE        14
#define E_SECOND        17
#define E_YEAR          20

static  int dcmp __P((struct tm *, struct tm *));
static  time_t emitl __P((struct tm *));
static  int lookup __P((char *));


time_t
unctime(str)
        char *str;
{
        struct tm then;
        char dbuf[26];

        (void) strncpy(dbuf, str, sizeof(dbuf) - 1);
        dbuf[sizeof(dbuf) - 1] = '\0';
        dbuf[E_MONTH+3] = '\0';
        if ((then.tm_mon = lookup(&dbuf[E_MONTH])) < 0)
                return (-1);
        then.tm_mday = atoi(&dbuf[E_DAY]);
        then.tm_hour = atoi(&dbuf[E_HOUR]);
        then.tm_min = atoi(&dbuf[E_MINUTE]);
        then.tm_sec = atoi(&dbuf[E_SECOND]);
        then.tm_year = atoi(&dbuf[E_YEAR]) - 1900;
        return(emitl(&then));
}

static char months[] =
        "JanFebMarAprMayJunJulAugSepOctNovDec";

static int
lookup(str)
        char *str;
{
        register char *cp, *cp2;

        for (cp = months, cp2 = str; *cp != '\0'; cp += 3)
                if (strncmp(cp, cp2, 3) == 0)
                        return((cp-months) / 3);
        return(-1);
}
/*
 * Routine to convert a localtime(3) format date back into
 * a system format date.
 *
 *      Use a binary search.
 */

static time_t
emitl(dp)
        struct tm *dp;
{
        time_t conv;
        register int i, bit;
        struct tm dcopy;

        dcopy = *dp;
        dp = &dcopy;
        conv = 0;
        for (i = 30; i >= 0; i--) {
                bit = 1 << i;
                conv |= bit;
                if (dcmp(localtime(&conv), dp) > 0)
                        conv &= ~bit;
        }
        return(conv);
}

/*
 * Compare two localtime dates, return result.
 */

#define DECIDE(a) \
        if (dp->a > dp2->a) \
                return(1); \
        if (dp->a < dp2->a) \
                return(-1)

static int
dcmp(dp, dp2)
        register struct tm *dp, *dp2;
{

        DECIDE(tm_year);
        DECIDE(tm_mon);
        DECIDE(tm_mday);
        DECIDE(tm_hour);
        DECIDE(tm_min);
        DECIDE(tm_sec);
        return(0);
}