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catgets.c revision 1.9 
      1 /*	$NetBSD: catgets.c,v 1.9 1996/10/09 01:46:13 jtc 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 *) (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 *) (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