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catgets.c revision 1.11 
      1 /*	$NetBSD: catgets.c,v 1.11 1997/07/13 19:58:36 christos 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 "namespace.h"
     42 #include <errno.h>
     43 #include <stdlib.h>
     44 #include <string.h>
     45 #include <nl_types.h>
     46 
     47 char *
     48 _catgets(catd, set_id, msg_id, s)
     49 	nl_catd catd;
     50 	int set_id;
     51 	int msg_id;
     52 	const char *s;
     53 {
     54 	struct _nls_cat_hdr *cat_hdr;
     55 	struct _nls_set_hdr *set_hdr;
     56 	struct _nls_msg_hdr *msg_hdr;
     57 	int l, u, i, r;
     58 
     59 	if (catd == (nl_catd) -1) {
     60 		errno = EBADF;
     61 		return (char *) s;
     62 	}
     63 
     64 	cat_hdr = (struct _nls_cat_hdr *) catd->__data;
     65 	set_hdr = (struct _nls_set_hdr *) ((char *) catd->__data
     66 		+ sizeof(struct _nls_cat_hdr));
     67 
     68 	/* binary search, see knuth algorithm b */
     69 	l = 0;
     70 	u = ntohl(cat_hdr->__nsets) - 1;
     71 	while (l <= u) {
     72 		i = (l + u) / 2;
     73 		r = set_id - ntohl(set_hdr[i].__setno);
     74 
     75 		if (r == 0) {
     76 			msg_hdr = (struct _nls_msg_hdr *) ((char *)catd->__data
     77 				+ sizeof(struct _nls_cat_hdr)
     78 				+ ntohl(cat_hdr->__msg_hdr_offset));
     79 
     80 			l = ntohl(set_hdr[i].__index);
     81 			u = l + ntohl(set_hdr[i].__nmsgs) - 1;
     82 			while (l <= u) {
     83 				i = (l + u) / 2;
     84 				r = msg_id - ntohl(msg_hdr[i].__msgno);
     85 				if (r == 0) {
     86 					return ((char *) catd->__data
     87 					    + sizeof(struct _nls_cat_hdr)
     88 					    + ntohl(cat_hdr->__msg_txt_offset)
     89 					    + ntohl(msg_hdr[i].__offset));
     90 				} else if (r < 0) {
     91 					u = i - 1;
     92 				} else {
     93 					l = i + 1;
     94 				}
     95 			}
     96 
     97 			/* not found */
     98 			return (char *) s;
     99 
    100 		} else if (r < 0) {
    101 			u = i - 1;
    102 		} else {
    103 			l = i + 1;
    104 		}
    105 	}
    106 
    107 	/* not found */
    108 	return (char *) s;
    109 }
    110