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      1 /* $NetBSD: nan.c,v 1.3 2017/03/07 11:15:08 maya 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  *
     19  * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
     20  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
     21  * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
     22  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
     23  * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
     24  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
     25  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
     26  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
     27  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
     28  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
     29  * POSSIBILITY OF SUCH DAMAGE.
     30  */
     31 
     32 #include <sys/cdefs.h>
     33 #if defined(LIBM_SCCS) && !defined(lint) && !defined(NAN_FUNCTION)
     34 __RCSID("$NetBSD: nan.c,v 1.3 2017/03/07 11:15:08 maya Exp $");
     35 #endif /* LIBM_SCCS and not lint */
     36 
     37 #include <assert.h>
     38 #include <math.h>
     39 #include <stddef.h>
     40 #include <stdlib.h>
     41 #include <string.h>
     42 
     43 
     44 #ifndef NAN_FUNCTION
     45 #define	NAN_FUNCTION	nan
     46 #define	NAN_TYPE	double
     47 #define	NAN_STRTOD	strtod
     48 #endif
     49 
     50 NAN_TYPE
     51 NAN_FUNCTION(const char *tagp)
     52 {
     53 	const char *nstr;
     54 	char *buf;
     55 	NAN_TYPE res;
     56 
     57 	_DIAGASSERT(tagp != NULL);
     58 
     59 	nstr = "NAN()";
     60 	buf = NULL;
     61 
     62 	if (tagp[0] != '\0') {
     63 		size_t l;
     64 
     65 		l = strlen(tagp);
     66 		buf = malloc(5 + l + 1);
     67 
     68 		if (buf != NULL) {
     69 			/* Avoiding stdio in libm. */
     70 			memcpy(buf,		"NAN(",	4);
     71 			memcpy(buf + 4,		tagp,	l);
     72 			memcpy(buf + 4 + l,	")",	2);
     73 			nstr = buf;
     74 		} else {
     75 			/* Best effort: Fall back to "NAN()". */
     76 		}
     77 	}
     78 
     79 	res = NAN_STRTOD(nstr, NULL);
     80 
     81 	free(buf);
     82 
     83 	return res;
     84 }
     85