mystring.c revision 50471 
1/*-
2 * Copyright (c) 1991, 1993
3 *	The Regents of the University of California.  All rights reserved.
4 *
5 * This code is derived from software contributed to Berkeley by
6 * Kenneth Almquist.
7 *
8 * Redistribution and use in source and binary forms, with or without
9 * modification, are permitted provided that the following conditions
10 * are met:
11 * 1. Redistributions of source code must retain the above copyright
12 *    notice, this list of conditions and the following disclaimer.
13 * 2. Redistributions in binary form must reproduce the above copyright
14 *    notice, this list of conditions and the following disclaimer in the
15 *    documentation and/or other materials provided with the distribution.
16 * 3. All advertising materials mentioning features or use of this software
17 *    must display the following acknowledgement:
18 *	This product includes software developed by the University of
19 *	California, Berkeley and its contributors.
20 * 4. Neither the name of the University nor the names of its contributors
21 *    may be used to endorse or promote products derived from this software
22 *    without specific prior written permission.
23 *
24 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
25 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
26 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
27 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
28 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
29 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
30 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
31 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
32 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
33 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
34 * SUCH DAMAGE.
35 */
36
37#ifndef lint
38#if 0
39static char sccsid[] = "@(#)mystring.c	8.2 (Berkeley) 5/4/95";
40#endif
41static const char rcsid[] =
42  "$FreeBSD: head/bin/sh/mystring.c 50471 1999-08-27 23:15:48Z peter $";
43#endif /* not lint */
44
45/*
46 * String functions.
47 *
48 *	equal(s1, s2)		Return true if strings are equal.
49 *	scopy(from, to)		Copy a string.
50 *	scopyn(from, to, n)	Like scopy, but checks for overflow.
51 *	number(s)		Convert a string of digits to an integer.
52 *	is_number(s)		Return true if s is a string of digits.
53 */
54
55#include <stdlib.h>
56#include "shell.h"
57#include "syntax.h"
58#include "error.h"
59#include "mystring.h"
60
61
62char nullstr[1];		/* zero length string */
63
64/*
65 * equal - #defined in mystring.h
66 */
67
68/*
69 * scopy - #defined in mystring.h
70 */
71
72
73/*
74 * scopyn - copy a string from "from" to "to", truncating the string
75 *		if necessary.  "To" is always nul terminated, even if
76 *		truncation is performed.  "Size" is the size of "to".
77 */
78
79void
80scopyn(from, to, size)
81	char const *from;
82	char *to;
83	int size;
84	{
85
86	while (--size > 0) {
87		if ((*to++ = *from++) == '\0')
88			return;
89	}
90	*to = '\0';
91}
92
93
94/*
95 * prefix -- see if pfx is a prefix of string.
96 */
97
98int
99prefix(pfx, string)
100	char const *pfx;
101	char const *string;
102	{
103	while (*pfx) {
104		if (*pfx++ != *string++)
105			return 0;
106	}
107	return 1;
108}
109
110
111/*
112 * Convert a string of digits to an integer, printing an error message on
113 * failure.
114 */
115
116int
117number(s)
118	const char *s;
119	{
120
121	if (! is_number(s))
122		error("Illegal number: %s", (char *)s);
123	return atoi(s);
124}
125
126
127
128/*
129 * Check for a valid number.  This should be elsewhere.
130 */
131
132int
133is_number(p)
134	const char *p;
135	{
136	do {
137		if (! is_digit(*p))
138			return 0;
139	} while (*++p != '\0');
140	return 1;
141}
142