/*

 * Copyright (c) 2004 by Internet Systems Consortium, Inc. ("ISC")

 * Copyright (c) 1999 by Internet Software Consortium.

 *

 * Permission to use, copy, modify, and distribute this software for any

 * purpose with or without fee is hereby granted, provided that the above

 * copyright notice and this permission notice appear in all copies.

 *

 * THE SOFTWARE IS PROVIDED "AS IS" AND ISC DISCLAIMS ALL WARRANTIES

 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF

 * MERCHANTABILITY AND FITNESS.  IN NO EVENT SHALL ISC BE LIABLE FOR

 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES

 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN

 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT

 * OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.

 */

/* Import. */

#include <arpa/nameser.h>

#include <ctype.h>

#include <errno.h>

#include <stdio.h>

#include <string.h>

#include <time.h>

#define SPRINTF(x) ((size_t)sprintf x)

/* Forward. */

static int	datepart(const char *, int, int, int, int *);

/* Public. */

/*%

 * Convert a date in ASCII into the number of seconds since

 * 1 January 1970 (GMT assumed).  Format is yyyymmddhhmmss, all

 * digits required, no spaces allowed.

 */

uint32_t

ns_datetosecs(const char *cp, int *errp) {

	struct tm time;

	uint32_t result;

	int mdays, i;

	static const int days_per_month[12] =

		{31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31};

	if (strlen(cp) != 14U) {

		*errp = 1;

		return (0);

	}

	*errp = 0;

	memset(&time, 0, sizeof time);

	time.tm_year  = datepart(cp +  0, 4, 1990, 9999, errp) - 1900;

	time.tm_mon   = datepart(cp +  4, 2,   01,   12, errp) - 1;

	time.tm_mday  = datepart(cp +  6, 2,   01,   31, errp);

	time.tm_hour  = datepart(cp +  8, 2,   00,   23, errp);

	time.tm_min   = datepart(cp + 10, 2,   00,   59, errp);

	time.tm_sec   = datepart(cp + 12, 2,   00,   59, errp);

	if (*errp)		/*%< Any parse errors? */

		return (0);

	/*

	 * OK, now because timegm() is not available in all environments,

	 * we will do it by hand.  Roll up sleeves, curse the gods, begin!

	 */

#define SECS_PER_DAY    ((uint32_t)24*60*60)

#define isleap(y) ((((y) % 4) == 0 && ((y) % 100) != 0) || ((y) % 400) == 0)

	result  = time.tm_sec;				/*%< Seconds */

	result += time.tm_min * 60;			/*%< Minutes */

	result += time.tm_hour * (60*60);		/*%< Hours */

	result += (time.tm_mday - 1) * SECS_PER_DAY;	/*%< Days */

	/* Months are trickier.  Look without leaping, then leap */

	mdays = 0;

	for (i = 0; i < time.tm_mon; i++)

		mdays += days_per_month[i];

	result += mdays * SECS_PER_DAY;			/*%< Months */

	if (time.tm_mon > 1 && isleap(1900+time.tm_year))

		result += SECS_PER_DAY;		/*%< Add leapday for this year */

	/* First figure years without leapdays, then add them in.  */

	/* The loop is slow, FIXME, but simple and accurate.  */

	result += (time.tm_year - 70) * (SECS_PER_DAY*365); /*%< Years */

	for (i = 70; i < time.tm_year; i++)

		if (isleap(1900+i))

			result += SECS_PER_DAY; /*%< Add leapday for prev year */

	return (result);

}

/* Private. */

/*%

 * Parse part of a date.  Set error flag if any error.

 * Don't reset the flag if there is no error.

 */

static int

datepart(const char *buf, int size, int min, int max, int *errp) {

	int result = 0;

	int i;

	for (i = 0; i < size; i++) {

		if (!isdigit((unsigned char)(buf[i])))

			*errp = 1;

		result = (result * 10) + buf[i] - '0';

	}

	if (result < min)

		*errp = 1;

	if (result > max)

		*errp = 1;

	return (result);

}

/*! \file */