lib/libc/nls/catgets.c
/*	$NetBSD: catgets.c,v 1.18 2008/04/28 20:23:00 martin Exp $	*/

/*-
 * Copyright (c) 1996 The NetBSD Foundation, Inc.
 * All rights reserved.
 *
 * This code is derived from software contributed to The NetBSD Foundation
 * by J.T. Conklin.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
 * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS 
 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 * POSSIBILITY OF SUCH DAMAGE.
 */

#include <sys/cdefs.h>
#if defined(LIBC_SCCS) && !defined(lint)
__RCSID("$NetBSD: catgets.c,v 1.18 2008/04/28 20:23:00 martin Exp $");
#endif /* LIBC_SCCS and not lint */

#define _NLS_PRIVATE

#include "namespace.h"
#include <errno.h>
#include <stdlib.h>
#include <string.h>
#include <nl_types.h>

#ifdef __weak_alias
__weak_alias(catgets, _catgets)
#endif

char *
_catgets(catd, set_id, msg_id, s)
	nl_catd catd;
	int set_id;
	int msg_id;
	const char *s;
{
	struct _nls_cat_hdr *cat_hdr;
	struct _nls_set_hdr *set_hdr;
	struct _nls_msg_hdr *msg_hdr;
	int l, u, i, r;

	if (catd == (nl_catd) -1) {
		errno = EBADF;
		return __UNCONST(s);
	}

	cat_hdr = (struct _nls_cat_hdr *)catd->__data; 
	set_hdr = (struct _nls_set_hdr *)(void *)((char *)catd->__data
		+ sizeof(struct _nls_cat_hdr));

	/* binary search, see knuth algorithm b */
	l = 0;
	u = ntohl((u_int32_t)cat_hdr->__nsets) - 1;
	while (l <= u) {
		i = (l + u) / 2;
		r = set_id - ntohl((u_int32_t)set_hdr[i].__setno);

		if (r == 0) {
			msg_hdr = (struct _nls_msg_hdr *)
			    (void *)((char *)catd->__data +
			    sizeof(struct _nls_cat_hdr) +
			    ntohl((u_int32_t)cat_hdr->__msg_hdr_offset));

			l = ntohl((u_int32_t)set_hdr[i].__index);
			u = l + ntohl((u_int32_t)set_hdr[i].__nmsgs) - 1;
			while (l <= u) {
				i = (l + u) / 2;
				r = msg_id -
				    ntohl((u_int32_t)msg_hdr[i].__msgno);
				if (r == 0) {
					return ((char *) catd->__data +
					    sizeof(struct _nls_cat_hdr) +
					    ntohl((u_int32_t)
					    cat_hdr->__msg_txt_offset) +
					    ntohl((u_int32_t)
					    msg_hdr[i].__offset));
				} else if (r < 0) {
					u = i - 1;
				} else {
					l = i + 1;
				}
			}

			/* not found */
			goto notfound;

		} else if (r < 0) {
			u = i - 1;
		} else {
			l = i + 1;
		}
	}

notfound:
	/* not found */
	errno = ENOMSG;
	return __UNCONST(s);
}
