xref: /netbsd-src/lib/libc/nls/catgets.c (revision fdecd6a253f999ae92b139670d9e15cc9df4497c)
1 /*	$NetBSD: catgets.c,v 1.10 1997/06/19 07:41:32 mikel Exp $	*/
2 
3 /*-
4  * Copyright (c) 1996 The NetBSD Foundation, Inc.
5  * All rights reserved.
6  *
7  * This code is derived from software contributed to The NetBSD Foundation
8  * by J.T. Conklin.
9  *
10  * Redistribution and use in source and binary forms, with or without
11  * modification, are permitted provided that the following conditions
12  * are met:
13  * 1. Redistributions of source code must retain the above copyright
14  *    notice, this list of conditions and the following disclaimer.
15  * 2. Redistributions in binary form must reproduce the above copyright
16  *    notice, this list of conditions and the following disclaimer in the
17  *    documentation and/or other materials provided with the distribution.
18  * 3. All advertising materials mentioning features or use of this software
19  *    must display the following acknowledgement:
20  *        This product includes software developed by the NetBSD
21  *        Foundation, Inc. and its contributors.
22  * 4. Neither the name of The NetBSD Foundation nor the names of its
23  *    contributors may be used to endorse or promote products derived
24  *    from this software without specific prior written permission.
25  *
26  * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
27  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
28  * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
29  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE
30  * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
31  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
32  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
33  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
34  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
35  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
36  * POSSIBILITY OF SUCH DAMAGE.
37  */
38 
39 #define _NLS_PRIVATE
40 
41 #include <errno.h>
42 #include <stdlib.h>
43 #include <string.h>
44 #include <nl_types.h>
45 
46 char *
47 _catgets(catd, set_id, msg_id, s)
48 	nl_catd catd;
49 	int set_id;
50 	int msg_id;
51 	const char *s;
52 {
53 	struct _nls_cat_hdr *cat_hdr;
54 	struct _nls_set_hdr *set_hdr;
55 	struct _nls_msg_hdr *msg_hdr;
56 	int l, u, i, r;
57 
58 	if (catd == (nl_catd) -1) {
59 		errno = EBADF;
60 		return (char *) s;
61 	}
62 
63 	cat_hdr = (struct _nls_cat_hdr *) catd->__data;
64 	set_hdr = (struct _nls_set_hdr *) ((char *) catd->__data
65 		+ sizeof(struct _nls_cat_hdr));
66 
67 	/* binary search, see knuth algorithm b */
68 	l = 0;
69 	u = ntohl(cat_hdr->__nsets) - 1;
70 	while (l <= u) {
71 		i = (l + u) / 2;
72 		r = set_id - ntohl(set_hdr[i].__setno);
73 
74 		if (r == 0) {
75 			msg_hdr = (struct _nls_msg_hdr *) ((char *)catd->__data
76 				+ sizeof(struct _nls_cat_hdr)
77 				+ ntohl(cat_hdr->__msg_hdr_offset));
78 
79 			l = ntohl(set_hdr[i].__index);
80 			u = l + ntohl(set_hdr[i].__nmsgs) - 1;
81 			while (l <= u) {
82 				i = (l + u) / 2;
83 				r = msg_id - ntohl(msg_hdr[i].__msgno);
84 				if (r == 0) {
85 					return ((char *) catd->__data
86 					    + sizeof(struct _nls_cat_hdr)
87 					    + ntohl(cat_hdr->__msg_txt_offset)
88 					    + ntohl(msg_hdr[i].__offset));
89 				} else if (r < 0) {
90 					u = i - 1;
91 				} else {
92 					l = i + 1;
93 				}
94 			}
95 
96 			/* not found */
97 			return (char *) s;
98 
99 		} else if (r < 0) {
100 			u = i - 1;
101 		} else {
102 			l = i + 1;
103 		}
104 	}
105 
106 	/* not found */
107 	return (char *) s;
108 }
109