nan.c revision 1.1 
1/* $NetBSD: nan.c,v 1.1 2006/03/15 22:07:09 kleink Exp $ */
2
3/*-
4 * Copyright (c) 2006 The NetBSD Foundation, Inc.
5 * All rights reserved.
6 *
7 * This code is derived from software contributed to The NetBSD Foundation
8 * by Klaus Klein.
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 FOUNDATION OR CONTRIBUTORS
30 * BE 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#include <sys/cdefs.h>
40#if defined(LIBM_SCCS) && !defined(lint) && !defined(NAN_FUNCTION)
41__RCSID("$NetBSD: nan.c,v 1.1 2006/03/15 22:07:09 kleink Exp $");
42#endif /* LIBM_SCCS and not lint */
43
44#include <assert.h>
45#include <math.h>
46#include <stddef.h>
47#include <stdlib.h>
48#include <string.h>
49
50
51#ifndef NAN_FUNCTION
52#define	NAN_FUNCTION	nan
53#define	NAN_TYPE	double
54#define	NAN_STRTOD	strtod
55#endif
56
57NAN_TYPE
58NAN_FUNCTION(const char *tagp)
59{
60	const char *nstr;
61	char *buf;
62	NAN_TYPE res;
63
64	_DIAGASSERT(tagp != NULL);
65
66	nstr = "NAN()";
67	buf = NULL;
68
69	if (tagp[0] != '\0') {
70		size_t l;
71
72		l = strlen(tagp);
73		buf = malloc(5 + l + 1);
74
75		if (buf != NULL) {
76			/* Avoiding stdio in libm. */
77			memcpy(buf,		"NAN(",	4);
78			memcpy(buf + 4,		tagp,	l);
79			memcpy(buf + 4 + l,	")",	2);
80			nstr = buf;
81		} else {
82			/* Best effort: Fall back to "NAN()". */
83		}
84	}
85
86	res = NAN_STRTOD(nstr, NULL);
87
88	if (buf != NULL)
89		free(buf);
90
91	return res;
92}
93