MFC: Document -f.
[dragonfly.git] / bin / sh / mystring.c
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1 /*-
2 * Copyright (c) 1991, 1993
3 * The Regents of the University of California. All rights reserved.
5 * This code is derived from software contributed to Berkeley by
6 * Kenneth Almquist.
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.
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.
36 * @(#)mystring.c 8.2 (Berkeley) 5/4/95
37 * $FreeBSD: src/bin/sh/mystring.c,v 1.10.2.1 2002/07/19 04:38:52 tjr Exp $
38 * $DragonFly: src/bin/sh/mystring.c,v 1.3 2004/03/19 18:39:41 cpressey Exp $
42 * String functions.
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.
51 #include <stdlib.h>
52 #include "shell.h"
53 #include "syntax.h"
54 #include "error.h"
55 #include "mystring.h"
58 char nullstr[1]; /* zero length string */
61 * equal - #defined in mystring.h
65 * scopy - #defined in mystring.h
70 * scopyn - copy a string from "from" to "to", truncating the string
71 * if necessary. "To" is always nul terminated, even if
72 * truncation is performed. "Size" is the size of "to".
75 void
76 scopyn(const char *from, char *to, int size)
79 while (--size > 0) {
80 if ((*to++ = *from++) == '\0')
81 return;
83 *to = '\0';
88 * prefix -- see if pfx is a prefix of string.
91 int
92 prefix(const char *pfx, const char *string)
94 while (*pfx) {
95 if (*pfx++ != *string++)
96 return 0;
98 return 1;
103 * Convert a string of digits to an integer, printing an error message on
104 * failure.
108 number(const char *s)
110 if (! is_number(s))
111 error("Illegal number: %s", s);
112 return atoi(s);
118 * Check for a valid number. This should be elsewhere.
122 is_number(const char *p)
124 do {
125 if (! is_digit(*p))
126 return 0;
127 } while (*++p != '\0');
128 return 1;