stdlib/OpenBSD/ecvt.c

   1 /*      $OpenBSD: ecvt.c,v 1.7 2009/10/16 12:15:03 martynas Exp $       */
   2
   3 /*
   4  * Copyright (c) 2002, 2006 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 #include <sys/cdefs.h>
  24 #include <stdio.h>
  25 #include <stdlib.h>
  26 #include <string.h>
  27
  28 extern char *__dtoa(double, int, int, int *, int *, char **);
  29 extern void  __freedtoa(char *);
  30 static char *__cvt(double, int, int *, int *, int, int);
  31
  32 static char *
  33 __cvt(double value, int ndigit, int * __restrict decpt, int * __restrict sign, int fmode, int pad)
  34 {
  35         static char *s;
  36         char *p, *rve, c;
  37         size_t siz;
  38
  39         if (ndigit == 0) {
  40                 *sign = value < 0.0;
  41                 *decpt = 0;
  42                 return ("");
  43         }
  44
  45         if (s) {
  46                 free(s);
  47                 s = NULL;
  48         }
  49
  50         if (ndigit < 0)
  51                 siz = -ndigit + 1;
  52         else
  53                 siz = ndigit + 1;
  54
  55
  56         /* __dtoa() doesn't allocate space for 0 so we do it by hand */
  57         if (value == 0.0) {
  58                 *decpt = 1 - fmode;     /* 1 for 'e', 0 for 'f' */
  59                 *sign = 0;
  60                 if ((rve = s = (char *)malloc(siz)) == NULL)
  61                         return(NULL);
  62                 *rve++ = '0';
  63                 *rve = '\0';
  64         } else {
  65                 p = __dtoa(value, fmode + 2, ndigit, decpt, sign, &rve);
  66                 if (p == NULL)
  67                         return (NULL);
  68                 if (*decpt == 9999) {
  69                         /* Infinity or Nan, convert to inf or nan like printf */
  70                         *decpt = 0;
  71                         c = *p;
  72                         __freedtoa(p);
  73                         return(c == 'I' ? "inf" : "nan");
  74                 }
  75                 /* Make a local copy and adjust rve to be in terms of s */
  76                 if (pad && fmode)
  77                         siz += *decpt;
  78                 if ((s = (char *)malloc(siz)) == NULL) {
  79                         __freedtoa(p);
  80                         return(NULL);
  81                 }
  82                 (void) strlcpy(s, p, siz);
  83                 rve = s + (rve - p);
  84                 __freedtoa(p);
  85         }
  86
  87         /* Add trailing zeros */
  88         if (pad) {
  89                 siz -= rve - s;
  90                 while (--siz)
  91                         *rve++ = '0';
  92                 *rve = '\0';
  93         }
  94
  95         return(s);
  96 }
  97
  98 char *
  99 ecvt(double value, int ndigit, int * __restrict decpt, int * __restrict sign)
 100 {
 101         return(__cvt(value, ndigit, decpt, sign, 0, 1));
 102 }
 103
 104 char *
 105 fcvt(double value, int ndigit, int * __restrict decpt, int * __restrict sign)
 106 {
 107         return(__cvt(value, ndigit, decpt, sign, 1, 1));
 108 }