/*******************************************************************
*                                                                  *
*             This software is part of the ast package             *
*                Copyright (c) 1985-2004 AT&T Corp.                *
*        and it may only be used by you under license from         *
*                       AT&T Corp. ("AT&T")                        *
*         A copy of the Source Code Agreement is available         *
*                at the AT&T Internet web site URL                 *
*                                                                  *
*       http://www.research.att.com/sw/license/ast-open.html       *
*                                                                  *
*    If you have copied or used this software without agreeing     *
*        to the terms of the license you are infringing on         *
*           the license and copyright and are violating            *
*               AT&T's intellectual property rights.               *
*                                                                  *
*            Information and Software Systems Research             *
*                        AT&T Labs Research                        *
*                         Florham Park NJ                          *
*                                                                  *
*               Glenn Fowler <gsf@research.att.com>                *
*                David Korn <dgk@research.att.com>                 *
*                 Phong Vo <kpv@research.att.com>                  *
*                                                                  *
*******************************************************************/
#pragma prototyped
/*
 * Glenn Fowler
 * AT&T Bell Laboratories
 *
 * time conversion support
 */

#include <ast.h>
#include <tm.h>
#include <ctype.h>

/*
 * return minutes offset from absolute timezone expression
 *
 *	[[-+]hh[:mm[:ss]]]
 *	[-+]hhmm
 *
 * if e is non-null then it points to the first unrecognized char in s
 * d returned if no offset in s
 */

int
tmgoff(register const char* s, char** e, int d)
{
	register int	n = d;
	int		east;
	const char*	t = s;

	if ((east = *s == '+') || *s == '-')
	{
		s++;
		if (isdigit(*s) && isdigit(*(s + 1)))
		{
			n = ((*s - '0') * 10 + (*(s + 1) - '0')) * 60;
			s += 2;
			if (*s == ':')
				s++;
			if (isdigit(*s) && isdigit(*(s + 1)))
			{
				n += ((*s - '0') * 10 + (*(s + 1) - '0'));
				s += 2;
				if (*s == ':')
					s++;
				if (isdigit(*s) && isdigit(*(s + 1)))
					s += 2;
			}
			if (east)
				n = -n;
			t = s;
		}
	}
	if (e)
		*e = (char*)t;
	return n;
}
