xref: /freebsd/bin/sh/mystring.c (revision 380a989b3223d455375b4fae70fd0b9bdd43bafb)
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
38 #if 0
39 static char sccsid[] = "@(#)mystring.c	8.2 (Berkeley) 5/4/95";
40 #endif
41 static const char rcsid[] =
42 	"$Id$";
43 #endif /* not lint */
44 
45 /*
46  * String functions.
47  *
48  *	equal(s1, s2)		Return true if strings are equal.
49  *	scopy(from, to)		Copy a string.
50  *	scopyn(from, to, n)	Like scopy, but checks for overflow.
51  *	number(s)		Convert a string of digits to an integer.
52  *	is_number(s)		Return true if s is a string of digits.
53  */
54 
55 #include <stdlib.h>
56 #include "shell.h"
57 #include "syntax.h"
58 #include "error.h"
59 #include "mystring.h"
60 
61 
62 char nullstr[1];		/* zero length string */
63 
64 /*
65  * equal - #defined in mystring.h
66  */
67 
68 /*
69  * scopy - #defined in mystring.h
70  */
71 
72 
73 /*
74  * scopyn - copy a string from "from" to "to", truncating the string
75  *		if necessary.  "To" is always nul terminated, even if
76  *		truncation is performed.  "Size" is the size of "to".
77  */
78 
79 void
80 scopyn(from, to, size)
81 	char const *from;
82 	char *to;
83 	int size;
84 	{
85 
86 	while (--size > 0) {
87 		if ((*to++ = *from++) == '\0')
88 			return;
89 	}
90 	*to = '\0';
91 }
92 
93 
94 /*
95  * prefix -- see if pfx is a prefix of string.
96  */
97 
98 int
99 prefix(pfx, string)
100 	char const *pfx;
101 	char const *string;
102 	{
103 	while (*pfx) {
104 		if (*pfx++ != *string++)
105 			return 0;
106 	}
107 	return 1;
108 }
109 
110 
111 /*
112  * Convert a string of digits to an integer, printing an error message on
113  * failure.
114  */
115 
116 int
117 number(s)
118 	const char *s;
119 	{
120 
121 	if (! is_number(s))
122 		error("Illegal number: %s", (char *)s);
123 	return atoi(s);
124 }
125 
126 
127 
128 /*
129  * Check for a valid number.  This should be elsewhere.
130  */
131 
132 int
133 is_number(p)
134 	const char *p;
135 	{
136 	do {
137 		if (! is_digit(*p))
138 			return 0;
139 	} while (*++p != '\0');
140 	return 1;
141 }
142