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  }