/* $NetBSD: nan.c,v 1.3 2017/03/07 11:15:08 maya Exp $ */

/*-
* Copyright (c) 2006 The NetBSD Foundation, Inc.
* All rights reserved.
*
* This code is derived from software contributed to The NetBSD Foundation
* by Klaus Klein.
*
* 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(LIBM_SCCS) && !defined(lint) && !defined(NAN_FUNCTION)
__RCSID("$NetBSD: nan.c,v 1.3 2017/03/07 11:15:08 maya Exp $");
#endif /* LIBM_SCCS and not lint */

#include <assert.h>
#include <math.h>
#include <stddef.h>
#include <stdlib.h>
#include <string.h>


#ifndef NAN_FUNCTION
#define NAN_FUNCTION    nan
#define NAN_TYPE        double
#define NAN_STRTOD      strtod
#endif

NAN_TYPE
NAN_FUNCTION(const char *tagp)
{
       const char *nstr;
       char *buf;
       NAN_TYPE res;

       _DIAGASSERT(tagp != NULL);

       nstr = "NAN()";
       buf = NULL;

       if (tagp[0] != '\0') {
               size_t l;

               l = strlen(tagp);
               buf = malloc(5 + l + 1);

               if (buf != NULL) {
                       /* Avoiding stdio in libm. */
                       memcpy(buf,             "NAN(", 4);
                       memcpy(buf + 4,         tagp,   l);
                       memcpy(buf + 4 + l,     ")",    2);
                       nstr = buf;
               } else {
                       /* Best effort: Fall back to "NAN()". */
               }
       }

       res = NAN_STRTOD(nstr, NULL);

       free(buf);

       return res;
}