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      1 /*	$NetBSD: catgets.c,v 1.20 2025/12/16 12:39:02 nia 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  *
     19  * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
     20  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
     21  * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
     22  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
     23  * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
     24  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
     25  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
     26  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
     27  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
     28  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
     29  * POSSIBILITY OF SUCH DAMAGE.
     30  */
     31 
     32 #include <sys/cdefs.h>
     33 #if defined(LIBC_SCCS) && !defined(lint)
     34 __RCSID("$NetBSD: catgets.c,v 1.20 2025/12/16 12:39:02 nia Exp $");
     35 #endif /* LIBC_SCCS and not lint */
     36 
     37 #define _NLS_PRIVATE
     38 
     39 #include "namespace.h"
     40 #include <sys/endian.h>
     41 #include <errno.h>
     42 #include <stdlib.h>
     43 #include <string.h>
     44 #include <nl_types.h>
     45 
     46 #ifdef __weak_alias
     47 __weak_alias(catgets, _catgets)
     48 #endif
     49 
     50 char *
     51 _catgets(nl_catd catd, int set_id, int msg_id, 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 __UNCONST(s);
     61 	}
     62 
     63 	cat_hdr = (struct _nls_cat_hdr *)catd->__data;
     64 	set_hdr = (struct _nls_set_hdr *)(void *)((char *)catd->__data
     65 		+ sizeof(struct _nls_cat_hdr));
     66 
     67 	/* binary search, see knuth algorithm b */
     68 	l = 0;
     69 	u = ntohl((u_int32_t)cat_hdr->__nsets) - 1;
     70 	while (l <= u) {
     71 		i = (l + u) / 2;
     72 		r = set_id - ntohl((u_int32_t)set_hdr[i].__setno);
     73 
     74 		if (r == 0) {
     75 			msg_hdr = (struct _nls_msg_hdr *)
     76 			    (void *)((char *)catd->__data +
     77 			    sizeof(struct _nls_cat_hdr) +
     78 			    ntohl((u_int32_t)cat_hdr->__msg_hdr_offset));
     79 
     80 			l = ntohl((u_int32_t)set_hdr[i].__index);
     81 			u = l + ntohl((u_int32_t)set_hdr[i].__nmsgs) - 1;
     82 			while (l <= u) {
     83 				i = (l + u) / 2;
     84 				r = msg_id -
     85 				    ntohl((u_int32_t)msg_hdr[i].__msgno);
     86 				if (r == 0) {
     87 					return ((char *) catd->__data +
     88 					    sizeof(struct _nls_cat_hdr) +
     89 					    ntohl((u_int32_t)
     90 					    cat_hdr->__msg_txt_offset) +
     91 					    ntohl((u_int32_t)
     92 					    msg_hdr[i].__offset));
     93 				} else if (r < 0) {
     94 					u = i - 1;
     95 				} else {
     96 					l = i + 1;
     97 				}
     98 			}
     99 
    100 			/* not found */
    101 			goto notfound;
    102 
    103 		} else if (r < 0) {
    104 			u = i - 1;
    105 		} else {
    106 			l = i + 1;
    107 		}
    108 	}
    109 
    110 notfound:
    111 	/* not found */
    112 	errno = ENOMSG;
    113 	return __UNCONST(s);
    114 }
    115