mystring.c revision 225736 
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 * 4. Neither the name of the University nor the names of its contributors
17 *    may be used to endorse or promote products derived from this software
18 *    without specific prior written permission.
19 *
20 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
21 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
22 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
23 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
24 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
25 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
26 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
27 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
28 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
29 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
30 * SUCH DAMAGE.
31 */
32
33#ifndef lint
34#if 0
35static char sccsid[] = "@(#)mystring.c	8.2 (Berkeley) 5/4/95";
36#endif
37#endif /* not lint */
38#include <sys/cdefs.h>
39__FBSDID("$FreeBSD: stable/9/bin/sh/mystring.c 201053 2009-12-27 18:04:05Z jilles $");
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 <stdlib.h>
52#include "shell.h"
53#include "syntax.h"
54#include "error.h"
55#include "mystring.h"
56
57
58char nullstr[1];		/* zero length string */
59
60/*
61 * equal - #defined in mystring.h
62 */
63
64/*
65 * scopy - #defined in mystring.h
66 */
67
68
69/*
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".
73 */
74
75void
76scopyn(const char *from, char *to, int size)
77{
78
79	while (--size > 0) {
80		if ((*to++ = *from++) == '\0')
81			return;
82	}
83	*to = '\0';
84}
85
86
87/*
88 * prefix -- see if pfx is a prefix of string.
89 */
90
91int
92prefix(const char *pfx, const char *string)
93{
94	while (*pfx) {
95		if (*pfx++ != *string++)
96			return 0;
97	}
98	return 1;
99}
100
101
102/*
103 * Convert a string of digits to an integer, printing an error message on
104 * failure.
105 */
106
107int
108number(const char *s)
109{
110	if (! is_number(s))
111		error("Illegal number: %s", s);
112	return atoi(s);
113}
114
115
116
117/*
118 * Check for a valid number.  This should be elsewhere.
119 */
120
121int
122is_number(const char *p)
123{
124	do {
125		if (! is_digit(*p))
126			return 0;
127	} while (*++p != '\0');
128	return 1;
129}
130