xref: /src/bin/sh/mystring.c

/*	$NetBSD: mystring.c,v 1.21 2024/07/13 13:43:58 kre Exp $	*/

/*-
 * Copyright (c) 1991, 1993
 *	The Regents of the University of California.  All rights reserved.
 *
 * This code is derived from software contributed to Berkeley by
 * Kenneth Almquist.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. Neither the name of the University nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 */

#include <sys/cdefs.h>
#ifndef lint
#if 0
static char sccsid[] = "@(#)mystring.c	8.2 (Berkeley) 5/4/95";
#else
__RCSID("$NetBSD: mystring.c,v 1.21 2024/07/13 13:43:58 kre Exp $");
#endif
#endif /* not lint */

/*
 * String functions.
 *
 *	equal(s1, s2)		Return true if strings are equal.
 *	scopy(from, to)		Copy a string.
 *	scopyn(from, to, n)	Like scopy, but checks for overflow.
 *	number(s)		Convert a string of digits to an integer.
 *	is_number(s)		Return true if s is a string of digits.
 */

#include <inttypes.h>
#include <limits.h>
#include <stdlib.h>
#include <strings.h>

#include "shell.h"
#include "syntax.h"
#include "error.h"
#include "mystring.h"


const char nullstr[1];		/* zero length string */

/*
 * equal - #defined in mystring.h
 */

/*
 * scopy - #defined in mystring.h
 */


/*
 * scopyn - copy a string from "from" to "to", truncating the string
 *		if necessary.  "To" is always nul terminated, even if
 *		truncation is performed.  "Size" is the size of "to".
 */

void
scopyn(const char *from, char *to, int size)
{

	while (--size > 0) {
		if ((*to++ = *from++) == '\0')
			return;
	}
	*to = '\0';
}


/*
 * prefix -- see if pfx is a prefix of string.
 */

int
prefix(const char *pfx, const char *string)
{
	while (*pfx) {
		if (*pfx++ != *string++)
			return 0;
	}
	return 1;
}


/*
 * Convert a string of digits to an integer, printing an error message on
 * failure.
 */

int
number(const char *s)
{
	char *ep = NULL;
	intmax_t n;

	if (!is_digit(*s) || ((n = strtoimax(s, &ep, 10)),
	    (ep == NULL || ep == s || *ep != '\0')))
		error("Invalid number: '%s'", s);
	if (n < INT_MIN || n > INT_MAX)
		error("Number out of range: %s", s);
	return (int)n;
}



/*
 * Check for a valid number.  This should be elsewhere.
 */

int
is_number(const char *p)
{
	do {
		if (! is_digit(*p))
			return 0;
	} while (*++p != '\0');
	return 1;
}

/*
 * Check a string for common representations of yes/true/...
 * Default result is false
 */

int
boolstr(const char *s)
{
	size_t len;

	if (s == NULL)
		return 0;

	len = strlen(s);
	if (len == 0)
		return 0;

	if (strncasecmp(s, "true", len) == 0		||
	    strncasecmp(s, "yes", len) == 0		||
	    (len == 2 && strcasecmp(s, "on") == 0)	||
	    is_digit(*s) || atoi(s) != 0)
		return 1;

	return 0;
}