mystring.c revision 262951 
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/10/bin/sh/mystring.c 262951 2014-03-09 17:04:31Z jmmv $");
40
41/*
42 * String functions.
43 *
44 *	equal(s1, s2)		Return true if strings are equal.
45 *	number(s)		Convert a string of digits to an integer.
46 *	is_number(s)		Return true if s is a string of digits.
47 */
48
49#include <stdlib.h>
50#include "shell.h"
51#include "syntax.h"
52#include "error.h"
53#include "mystring.h"
54
55
56char nullstr[1];		/* zero length string */
57
58/*
59 * equal - #defined in mystring.h
60 */
61
62
63/*
64 * prefix -- see if pfx is a prefix of string.
65 */
66
67int
68prefix(const char *pfx, const char *string)
69{
70	while (*pfx) {
71		if (*pfx++ != *string++)
72			return 0;
73	}
74	return 1;
75}
76
77
78/*
79 * Convert a string of digits to an integer, printing an error message on
80 * failure.
81 */
82
83int
84number(const char *s)
85{
86	if (! is_number(s))
87		error("Illegal number: %s", s);
88	return atoi(s);
89}
90
91
92
93/*
94 * Check for a valid number.  This should be elsewhere.
95 */
96
97int
98is_number(const char *p)
99{
100	do {
101		if (! is_digit(*p))
102			return 0;
103	} while (*++p != '\0');
104	return 1;
105}
106