/* $OpenBSD: strtonum.c,v 1.5 2004/07/16 18:36:05 otto Exp $ */
/* $DragonFly: src/lib/libc/stdlib/strtonum.c,v 1.1 2004/08/15 16:01:11 joerg Exp $ */
/*
 * Copyright (c) 2004 Ted Unangst and Todd Miller
 * All rights reserved.
 *
 * 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 THE AUTHOR DISCLAIMS ALL WARRANTIES
 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR 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.
 */

#include <errno.h>
#include <limits.h>
#include <stdlib.h>

#define INVALID 	1
#define TOOSMALL 	2
#define TOOLARGE 	3

static struct errval {
	const char *errstr;
	int err;
} ev[4] = {
	{ NULL,		0 },
	{ "invalid",	EINVAL },
	{ "too small",	ERANGE },
	{ "too large",	ERANGE },
};

unsigned long long
strtonum(const char *numstr, long long minval, unsigned long long umaxval,
	 const char **errstrp)
{
	long long ll, maxval = (long long)umaxval;
	unsigned long long ull = 0;
	char *ep;
	int error = 0;

	ev[0].err = errno;
	errno = 0;
	if (umaxval > LLONG_MAX ) {
		if (minval < 0) {
			error = INVALID;
			goto done;
		}
		ull = strtoull(numstr, &ep, 10);
		if (numstr == ep || *ep != '\0')
			error = INVALID;
		else if ((ull == ULLONG_MAX && errno == ERANGE) ||
			 ull > umaxval)
			error = TOOLARGE;
		else if (ull < minval)
			error = TOOSMALL;
	} else {
		if (minval > maxval || maxval < minval) {
			error = INVALID;
			goto done;
		}
		ll = strtoll(numstr, &ep, 10);
		if (numstr == ep || *ep != '\0')
			error = INVALID;
		else if ((ll == LLONG_MIN && errno == ERANGE) || ll < minval)
			error = TOOSMALL;
		else if ((ll == LLONG_MAX && errno == ERANGE) || ll > maxval)
			error = TOOLARGE;
		ull = (unsigned long long)ll;
	}
done:
	if (errstrp != NULL)
		*errstrp = ev[error].errstr;
	errno = ev[error].err;
	if (error)
		ull = 0;

	return(ull);
}