1 /* $OpenBSD: ecvt.c,v 1.6 2006/10/29 18:45:56 deraadt 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 <stdio.h> 24 #include <stdlib.h> 25 #include <string.h> 26 27 extern char *__dtoa(double, int, int, int *, int *, char **); 28 extern void __freedtoa(char *); 29 static char *__cvt(double, int, int *, int *, int, int); 30 31 static char * 32 __cvt(double value, int ndigit, int *decpt, int *sign, int fmode, int pad) 33 { 34 static char *s; 35 char *p, *rve, c; 36 size_t siz; 37 38 if (ndigit == 0) { 39 *sign = value < 0.0; 40 *decpt = 0; 41 return (""); 42 } 43 44 if (s) { 45 free(s); 46 s = NULL; 47 } 48 49 if (ndigit < 0) 50 siz = -ndigit + 1; 51 else 52 siz = ndigit + 1; 53 54 55 /* __dtoa() doesn't allocate space for 0 so we do it by hand */ 56 if (value == 0.0) { 57 *decpt = 1 - fmode; /* 1 for 'e', 0 for 'f' */ 58 *sign = 0; 59 if ((rve = s = (char *)malloc(siz)) == NULL) 60 return(NULL); 61 *rve++ = '0'; 62 *rve = '\0'; 63 } else { 64 p = __dtoa(value, fmode + 2, ndigit, decpt, sign, &rve); 65 if (*decpt == 9999) { 66 /* Infinity or Nan, convert to inf or nan like printf */ 67 *decpt = 0; 68 c = *p; 69 __freedtoa(p); 70 return(c == 'I' ? "inf" : "nan"); 71 } 72 /* Make a local copy and adjust rve to be in terms of s */ 73 if (pad && fmode) 74 siz += *decpt; 75 if ((s = (char *)malloc(siz)) == NULL) { 76 __freedtoa(p); 77 return(NULL); 78 } 79 (void) strlcpy(s, p, siz); 80 rve = s + (rve - p); 81 __freedtoa(p); 82 } 83 84 /* Add trailing zeros */ 85 if (pad) { 86 siz -= rve - s; 87 while (--siz) 88 *rve++ = '0'; 89 *rve = '\0'; 90 } 91 92 return(s); 93 } 94 95 char * 96 ecvt(double value, int ndigit, int *decpt, int *sign) 97 { 98 return(__cvt(value, ndigit, decpt, sign, 0, 1)); 99 } 100 101 char * 102 fcvt(double value, int ndigit, int *decpt, int *sign) 103 { 104 return(__cvt(value, ndigit, decpt, sign, 1, 1)); 105 } 106