shadow/libmisc/getrange.c

/*
 * SPDX-FileCopyrightText: 2008       , Nicolas François
 *
 * SPDX-License-Identifier: BSD-3-Clause
 */

#include <config.h>

#ident "$Id: $"

#include <ctype.h>
#include <stdlib.h>

#include "defines.h"
#include "prototypes.h"

/*
 * Parse a range and indicate if the range is valid.
 * Valid ranges are in the form:
 *     <long>          -> min=max=long         has_min  has_max
 *     -<long>         -> max=long            !has_min  has_max
 *     <long>-         -> min=long             has_min !has_max
 *     <long1>-<long2> -> min=long1 max=long2  has_min  has_max
 *
 * If the range is valid, getrange returns 1.
 * If the range is not valid, getrange returns 0.
 */
int getrange (const char *range,
              unsigned long *min, bool *has_min,
              unsigned long *max, bool *has_max)
{
	char *endptr;
	unsigned long n;

	if (NULL == range) {
		return 0;
	}

	if ('-' == range[0]) {
		if (!isdigit(range[1])) {
			/* invalid */
			return 0;
		}
		errno = 0;
		n = strtoul (&range[1], &endptr, 10);
		if (('\0' != *endptr) || (ERANGE == errno)) {
			/* invalid */
			return 0;
		}
		/* -<long> */
		*has_min = false;
		*has_max = true;
		*max = n;
	} else {
		errno = 0;
		n = strtoul (range, &endptr, 10);
		if (ERANGE == errno) {
			/* invalid */
			return 0;
		}
		switch (*endptr) {
			case '\0':
				/* <long> */
				*has_min = true;
				*has_max = true;
				*min = n;
				*max = n;
				break;
			case '-':
				endptr++;
				if ('\0' == *endptr) {
					/* <long>- */
					*has_min = true;
					*has_max = false;
					*min = n;
				} else if (!isdigit (*endptr)) {
					/* invalid */
					return 0;
				} else {
					*has_min = true;
					*min = n;
					errno = 0;
					n = strtoul (endptr, &endptr, 10);
					if (   ('\0' != *endptr)
					    || (ERANGE == errno)) {
						/* invalid */
						return 0;
					}
					/* <long>-<long> */
					*has_max = true;
					*max = n;
				}
				break;
			default:
				return 0;
		}
	}

	return 1;
}