xref: /freebsd/bin/sh/mystring.c (revision 405c3050f102b8c74782f0366c8ead927bd07b68)
1 /*-
2  * SPDX-License-Identifier: BSD-3-Clause
3  *
4  * Copyright (c) 1991, 1993
5  *	The Regents of the University of California.  All rights reserved.
6  *
7  * This code is derived from software contributed to Berkeley by
8  * Kenneth Almquist.
9  *
10  * Redistribution and use in source and binary forms, with or without
11  * modification, are permitted provided that the following conditions
12  * are met:
13  * 1. Redistributions of source code must retain the above copyright
14  *    notice, this list of conditions and the following disclaimer.
15  * 2. Redistributions in binary form must reproduce the above copyright
16  *    notice, this list of conditions and the following disclaimer in the
17  *    documentation and/or other materials provided with the distribution.
18  * 3. Neither the name of the University nor the names of its contributors
19  *    may be used to endorse or promote products derived from this software
20  *    without specific prior written permission.
21  *
22  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
23  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
24  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
25  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
26  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
27  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
28  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
29  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
30  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
31  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
32  * SUCH DAMAGE.
33  */
34 
35 #ifndef lint
36 #if 0
37 static char sccsid[] = "@(#)mystring.c	8.2 (Berkeley) 5/4/95";
38 #endif
39 #endif /* not lint */
40 #include <sys/cdefs.h>
41 __FBSDID("$FreeBSD$");
42 
43 /*
44  * String functions.
45  *
46  *	equal(s1, s2)		Return true if strings are equal.
47  *	number(s)		Convert a string of digits to an integer.
48  *	is_number(s)		Return true if s is a string of digits.
49  */
50 
51 #include <stdlib.h>
52 #include "shell.h"
53 #include "syntax.h"
54 #include "error.h"
55 #include "mystring.h"
56 
57 
58 char nullstr[1];		/* zero length string */
59 
60 /*
61  * equal - #defined in mystring.h
62  */
63 
64 
65 /*
66  * Convert a string of digits to an integer, printing an error message on
67  * failure.
68  */
69 
70 int
71 number(const char *s)
72 {
73 	if (! is_number(s))
74 		error("Illegal number: %s", s);
75 	return atoi(s);
76 }
77 
78 
79 
80 /*
81  * Check for a valid number.  This should be elsewhere.
82  */
83 
84 int
85 is_number(const char *p)
86 {
87 	const char *q;
88 
89 	if (*p == '\0')
90 		return 0;
91 	while (*p == '0')
92 		p++;
93 	for (q = p; *q != '\0'; q++)
94 		if (! is_digit(*q))
95 			return 0;
96 	if (q - p > 10 ||
97 	    (q - p == 10 && memcmp(p, "2147483647", 10) > 0))
98 		return 0;
99 	return 1;
100 }
101