stdlib/OpenBSD/ecvt.c

   1 /*      $OpenBSD: ecvt.c,v 1.3 2003/06/17 21:56:24 millert Exp $        */
   2
   3 /*
   4  * Copyright (c) 2002 Todd C. Miller <Todd.Miller@courtesan.com>
   5  *
   6  * Permission to use, copy, modify, and distribute this software for any
   7  * purpose with or without fee is hereby granted, provided that the above
   8  * copyright notice and this permission notice appear in all copies.
   9  *
  10  * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
  11  * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
  12  * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
  13  * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
  14  * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
  15  * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
  16  * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
  17  *
  18  * Sponsored in part by the Defense Advanced Research Projects
  19  * Agency (DARPA) and Air Force Research Laboratory, Air Force
  20  * Materiel Command, USAF, under agreement number F39502-99-1-0512.
  21  */
  22
  23 #if defined(LIBC_SCCS) && !defined(lint)
  24 static char rcsid[] = "$OpenBSD: ecvt.c,v 1.3 2003/06/17 21:56:24 millert Exp $";
  25 #endif /* LIBC_SCCS and not lint */
  26
  27 #include <stdio.h>
  28 #include <stdlib.h>
  29 #include <string.h>
  30
  31 extern char *__dtoa(double, int, int, int *, int *, char **);
  32 static char *__cvt(double, int, int *, int *, int, int);
  33
  34 static char *
  35 __cvt(double value, int ndigit, int *decpt, int *sign, int fmode, int pad)
  36 {
  37         static char *s;
  38         char *p, *rve;
  39         size_t siz;
  40
  41         if (ndigit == 0) {
  42                 *sign = value < 0.0;
  43                 *decpt = 0;
  44                 return ("");
  45         }
  46
  47         if (s) {
  48                 free(s);
  49                 s = NULL;
  50         }
  51
  52         if (ndigit < 0)
  53                 siz = -ndigit + 1;
  54         else
  55                 siz = ndigit + 1;
  56
  57
  58         /* __dtoa() doesn't allocate space for 0 so we do it by hand */
  59         if (value == 0.0) {
  60                 *decpt = 1 - fmode;     /* 1 for 'e', 0 for 'f' */
  61                 *sign = 0;
  62                 if ((rve = s = (char *)malloc(siz)) == NULL)
  63                         return(NULL);
  64                 *rve++ = '0';
  65                 *rve = '\0';
  66         } else {
  67                 p = __dtoa(value, fmode + 2, ndigit, decpt, sign, &rve);
  68                 if (*decpt == 9999) {
  69                         /* Nan or Infinity */
  70                         *decpt = 0;
  71                         return(p);
  72                 }
  73                 /* make a local copy and adjust rve to be in terms of s */
  74                 if (pad && fmode)
  75                         siz += *decpt;
  76                 if ((s = (char *)malloc(siz)) == NULL)
  77                         return(NULL);
  78                 (void) strlcpy(s, p, siz);
  79                 rve = s + (rve - p);
  80         }
  81
  82         /* Add trailing zeros (unless we got NaN or Inf) */
  83         if (pad && *decpt != 9999) {
  84                 siz -= rve - s;
  85                 while (--siz)
  86                         *rve++ = '0';
  87                 *rve = '\0';
  88         }
  89
  90         return(s);
  91 }
  92
  93 char *
  94 ecvt(double value, int ndigit, int *decpt, int *sign)
  95 {
  96         return(__cvt(value, ndigit, decpt, sign, 0, 1));
  97 }
  98
  99 char *
 100 fcvt(double value, int ndigit, int *decpt, int *sign)
 101 {
 102         return(__cvt(value, ndigit, decpt, sign, 1, 1));
 103 }