mystring.c revision 3044 
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 *	$Id$
37 */
38
39#ifndef lint
40static char sccsid[] = "@(#)mystring.c	8.1 (Berkeley) 5/31/93";
41#endif /* not lint */
42
43/*
44 * String functions.
45 *
46 *	equal(s1, s2)		Return true if strings are equal.
47 *	scopy(from, to)		Copy a string.
48 *	scopyn(from, to, n)	Like scopy, but checks for overflow.
49 *	number(s)		Convert a string of digits to an integer.
50 *	is_number(s)		Return true if s is a string of digits.
51 */
52
53#include "shell.h"
54#include "syntax.h"
55#include "error.h"
56#include "mystring.h"
57
58
59char nullstr[1];		/* zero length string */
60
61/*
62 * equal - #defined in mystring.h
63 */
64
65/*
66 * scopy - #defined in mystring.h
67 */
68
69
70/*
71 * scopyn - copy a string from "from" to "to", truncating the string
72 *		if necessary.  "To" is always nul terminated, even if
73 *		truncation is performed.  "Size" is the size of "to".
74 */
75
76void
77scopyn(from, to, size)
78	register char const *from;
79	register char *to;
80	register int size;
81	{
82
83	while (--size > 0) {
84		if ((*to++ = *from++) == '\0')
85			return;
86	}
87	*to = '\0';
88}
89
90
91/*
92 * prefix -- see if pfx is a prefix of string.
93 */
94
95int
96prefix(pfx, string)
97	register char const *pfx;
98	register char const *string;
99	{
100	while (*pfx) {
101		if (*pfx++ != *string++)
102			return 0;
103	}
104	return 1;
105}
106
107
108/*
109 * Convert a string of digits to an integer, printing an error message on
110 * failure.
111 */
112
113int
114number(s)
115	const char *s;
116	{
117
118	if (! is_number(s))
119		error2("Illegal number", (char *)s);
120	return atoi(s);
121}
122
123
124
125/*
126 * Check for a valid number.  This should be elsewhere.
127 */
128
129int
130is_number(p)
131	register const char *p;
132	{
133	do {
134		if (! is_digit(*p))
135			return 0;
136	} while (*++p != '\0');
137	return 1;
138}
139