lib/libm/gen/nan.c

   1 /*-
   2  * Copyright (c) 2006 The NetBSD Foundation, Inc.
   3  * All rights reserved.
   4  *
   5  * This code is derived from software contributed to The NetBSD Foundation
   6  * by Klaus Klein.
   7  *
   8  * Redistribution and use in source and binary forms, with or without
   9  * modification, are permitted provided that the following conditions
  10  * are met:
  11  * 1. Redistributions of source code must retain the above copyright
  12  *    notice, this list of conditions and the following disclaimer.
  13  * 2. Redistributions in binary form must reproduce the above copyright
  14  *    notice, this list of conditions and the following disclaimer in the
  15  *    documentation and/or other materials provided with the distribution.
  16  * 3. All advertising materials mentioning features or use of this software
  17  *    must display the following acknowledgement:
  18  *        This product includes software developed by the NetBSD
  19  *        Foundation, Inc. and its contributors.
  20  * 4. Neither the name of The NetBSD Foundation nor the names of its
  21  *    contributors may be used to endorse or promote products derived
  22  *    from this software without specific prior written permission.
  23  *
  24  * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
  25  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
  26  * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
  27  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
  28  * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
  29  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
  30  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
  31  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
  32  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
  33  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
  34  * POSSIBILITY OF SUCH DAMAGE.
  35  *
  36  * $NetBSD: nan.c,v 1.1 2006/03/15 22:07:09 kleink Exp $
  37  * $DragonFly: src/lib/libm/gen/nan.c,v 1.1 2007/06/17 17:46:01 pavalos Exp $
  38  */
  39
  40 #include <assert.h>
  41 #include <math.h>
  42 #include <stddef.h>
  43 #include <stdlib.h>
  44 #include <string.h>
  45
  46
  47 #ifndef NAN_FUNCTION
  48 #define NAN_FUNCTION    nan
  49 #define NAN_TYPE        double
  50 #define NAN_STRTOD      strtod
  51 #endif
  52
  53 NAN_TYPE
  54 NAN_FUNCTION(const char *tagp)
  55 {
  56         const char *nstr;
  57         char *buf;
  58         NAN_TYPE res;
  59
  60         _DIAGASSERT(tagp != NULL);
  61
  62         nstr = "NAN()";
  63         buf = NULL;
  64
  65         if (tagp[0] != '\0') {
  66                 size_t l;
  67
  68                 l = strlen(tagp);
  69                 buf = malloc(5 + l + 1);
  70
  71                 if (buf != NULL) {
  72                         /* Avoiding stdio in libm. */
  73                         memcpy(buf,             "NAN(", 4);
  74                         memcpy(buf + 4,         tagp,   l);
  75                         memcpy(buf + 4 + l,     ")",    2);
  76                         nstr = buf;
  77                 } else {
  78                         /* Best effort: Fall back to "NAN()". */
  79                 }
  80         }
  81
  82         res = NAN_STRTOD(nstr, NULL);
  83
  84         if (buf != NULL)
  85                 free(buf);
  86
  87         return res;
  88 }