source: trunk/minix/commands/ash/mystring.c@ 10

Last change on this file since 10 was 9, checked in by Mattia Monga, 13 years ago

Minix 3.1.2a

File size: 4.1 KB
Line 
1/*-
2 * Copyright (c) 1991 The Regents of the University of California.
3 * 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 5.1 (Berkeley) 3/7/91";
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 * strchr(s, c) Find first occurance of c in s.
48 * bcopy(from, to, n) Copy a block of memory.
49 * number(s) Convert a string of digits to an integer.
50 * is_number(s) Return true if s is a string of digits.
51 */
52
53#include "shell.h"
54#include "syntax.h"
55#include "error.h"
56#include "mystring.h"
57
58
59char nullstr[1]; /* zero length string */
60
61
62/*
63 * scopyn - copy a string from "from" to "to", truncating the string
64 * if necessary. "To" is always nul terminated, even if
65 * truncation is performed. "Size" is the size of "to".
66 */
67
68void
69scopyn(from, to, size)
70 register char const *from;
71 register char *to;
72 register int size;
73 {
74
75 while (--size > 0) {
76 if ((*to++ = *from++) == '\0')
77 return;
78 }
79 *to = '\0';
80}
81
82
83/*
84 * strchr - find first occurrence of a character in a string.
85 */
86
87#ifndef SYS5
88char *
89mystrchr(s, charwanted)
90 char const *s;
91 register char charwanted;
92 {
93 register char const *scan;
94
95 /*
96 * The odd placement of the two tests is so NUL is findable.
97 */
98 for (scan = s ; *scan != charwanted ; ) /* ++ moved down for opt. */
99 if (*scan++ == '\0')
100 return NULL;
101 return (char *)scan;
102}
103#endif
104
105
106
107/*
108 * bcopy - copy bytes
109 *
110 * This routine was derived from code by Henry Spencer.
111 */
112
113void
114mybcopy(src, dst, length)
115 pointer dst;
116 const pointer src;
117 register int length;
118 {
119 register char *d = dst;
120 register char *s = src;
121
122 while (--length >= 0)
123 *d++ = *s++;
124}
125
126
127/*
128 * prefix -- see if pfx is a prefix of string.
129 */
130
131int
132prefix(pfx, string)
133 register char const *pfx;
134 register char const *string;
135 {
136 while (*pfx) {
137 if (*pfx++ != *string++)
138 return 0;
139 }
140 return 1;
141}
142
143
144/*
145 * Convert a string of digits to an integer, printing an error message on
146 * failure.
147 */
148
149int
150number(s)
151 const char *s;
152 {
153
154 if (! is_number(s))
155 error2("Illegal number", (char *)s);
156 return atoi(s);
157}
158
159
160
161/*
162 * Check for a valid number. This should be elsewhere.
163 */
164
165int
166is_number(p)
167 register const char *p;
168 {
169 do {
170 if (! is_digit(*p))
171 return 0;
172 } while (*++p != '\0');
173 return 1;
174}
Note: See TracBrowser for help on using the repository browser.