mystring.c revision 1556 
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
38static char sccsid[] = "@(#)mystring.c	8.1 (Berkeley) 5/31/93";
39#endif /* not lint */
40
41/*
42 * String functions.
43 *
44 *	equal(s1, s2)		Return true if strings are equal.
45 *	scopy(from, to)		Copy a string.
46 *	scopyn(from, to, n)	Like scopy, but checks for overflow.
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 "shell.h"
52#include "syntax.h"
53#include "error.h"
54#include "mystring.h"
55
56
57char nullstr[1];		/* zero length string */
58
59/*
60 * equal - #defined in mystring.h
61 */
62
63/*
64 * scopy - #defined in mystring.h
65 */
66
67
68/*
69 * scopyn - copy a string from "from" to "to", truncating the string
70 *		if necessary.  "To" is always nul terminated, even if
71 *		truncation is performed.  "Size" is the size of "to".
72 */
73
74void
75scopyn(from, to, size)
76	register char const *from;
77	register char *to;
78	register int size;
79	{
80
81	while (--size > 0) {
82		if ((*to++ = *from++) == '\0')
83			return;
84	}
85	*to = '\0';
86}
87
88
89/*
90 * prefix -- see if pfx is a prefix of string.
91 */
92
93int
94prefix(pfx, string)
95	register char const *pfx;
96	register char const *string;
97	{
98	while (*pfx) {
99		if (*pfx++ != *string++)
100			return 0;
101	}
102	return 1;
103}
104
105
106/*
107 * Convert a string of digits to an integer, printing an error message on
108 * failure.
109 */
110
111int
112number(s)
113	const char *s;
114	{
115
116	if (! is_number(s))
117		error2("Illegal number", (char *)s);
118	return atoi(s);
119}
120
121
122
123/*
124 * Check for a valid number.  This should be elsewhere.
125 */
126
127int
128is_number(p)
129	register const char *p;
130	{
131	do {
132		if (! is_digit(*p))
133			return 0;
134	} while (*++p != '\0');
135	return 1;
136}
137