cosmopolitan/libc/stdio/ecvt.c

126 lines
4.1 KiB
C
Raw Normal View History

/*-*- mode:c;indent-tabs-mode:t;c-basic-offset:8;tab-width:8;coding:utf-8 -*-│
vi: set et ft=c ts=8 tw=8 fenc=utf-8 :vi
$OpenBSD: ecvt.c,v 1.11 2019/01/25 00:19:25 millert Exp $
Copyright (c) 2002, 2006 Todd C. Miller <millert@openbsd.org>
Permission to use, copy, modify, and distribute this software for any
purpose with or without fee is hereby granted, provided that the above
copyright notice and this permission notice appear in all copies.
THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
Sponsored in part by the Defense Advanced Research Projects
Agency (DARPA) and Air Force Research Laboratory, Air Force
Materiel Command, USAF, under agreement number F39502-99-1-0512.
SUCH DAMAGE.
*/
#include "libc/fmt/fmt.h"
#include "libc/mem/mem.h"
#include "libc/runtime/runtime.h"
#include "libc/str/str.h"
#include "third_party/gdtoa/gdtoa.h"
asm(".ident\t\"\\n\\n\
OpenBSD ecvt/gcvt (MIT)\\n\
Copyright (c) 2002, 2006, 2010 Todd C. Miller <millert@openbsd.org>\"");
asm(".include \"libc/disclaimer.inc\"");
// clang-format off
static char *s;
static void
__cvt_atexit(void)
{
free(s);
s = 0;
}
static void __attribute__((__constructor__))
__cvt_init(void)
{
atexit(__cvt_atexit);
}
static char *
__cvt(double value, int ndigit, int *decpt, int *sign, int fmode, int pad)
{
char *p, *rve, c;
size_t siz;
if (ndigit == 0) {
*sign = value < 0.0;
*decpt = 0;
return ("");
}
free(s);
s = NULL;
if (ndigit < 0)
siz = -ndigit + 1;
else
siz = ndigit + 1;
/* __dtoa() doesn't allocate space for 0 so we do it by hand */
if (value == 0.0) {
*decpt = 1 - fmode; /* 1 for 'e', 0 for 'f' */
*sign = 0;
if ((rve = s = malloc(siz)) == NULL)
return(NULL);
*rve++ = '0';
*rve = '\0';
} else {
p = dtoa(value, fmode + 2, ndigit, decpt, sign, &rve);
if (p == NULL)
return (NULL);
if (*decpt == 9999) {
/* Infinity or Nan, convert to inf or nan like printf */
*decpt = 0;
c = *p;
freedtoa(p);
return(c == 'I' ? "inf" : "nan");
}
/* Make a local copy and adjust rve to be in terms of s */
if (pad && fmode)
siz += *decpt;
if ((s = malloc(siz)) == NULL) {
freedtoa(p);
return(NULL);
}
(void) strlcpy(s, p, siz);
rve = s + (rve - p);
freedtoa(p);
}
/* Add trailing zeros */
if (pad) {
siz -= rve - s;
while (--siz)
*rve++ = '0';
*rve = '\0';
}
return(s);
}
char *
ecvt(double value, int ndigit, int *decpt, int *sign)
{
return(__cvt(value, ndigit, decpt, sign, 0, 1));
}
char *
fcvt(double value, int ndigit, int *decpt, int *sign)
{
return(__cvt(value, ndigit, decpt, sign, 1, 1));
}