cosmopolitan/third_party/gdtoa/g_dfmt.c
Jōshin 394d998315
Fix vi modelines (#989)
At least in neovim, `│vi:` is not recognized as a modeline because it
has no preceding whitespace. After fixing this, opening a file yields
an error because `net` is not an option. (`noet`, however, is.)
2023-12-05 14:37:54 -08:00

83 lines
4 KiB
C

/*-*- 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 │
╚──────────────────────────────────────────────────────────────────────────────╝
│ │
│ The author of this software is David M. Gay. │
│ Please send bug reports to David M. Gay <dmg@acm.org> │
│ or Justine Tunney <jtunney@gmail.com> │
│ │
│ Copyright (C) 1998, 1999 by Lucent Technologies │
│ All Rights Reserved │
│ │
│ Permission to use, copy, modify, and distribute this software and │
│ its documentation for any purpose and without fee is hereby │
│ granted, provided that the above copyright notice appear in all │
│ copies and that both that the copyright notice and this │
│ permission notice and warranty disclaimer appear in supporting │
│ documentation, and that the name of Lucent or any of its entities │
│ not be used in advertising or publicity pertaining to │
│ distribution of the software without specific, written prior │
│ permission. │
│ │
│ LUCENT DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS SOFTWARE, │
│ INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS. │
│ IN NO EVENT SHALL LUCENT OR ANY OF ITS ENTITIES BE LIABLE FOR ANY │
│ SPECIAL, 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. │
│ │
╚─────────────────────────────────────────────────────────────────────────────*/
#include "third_party/gdtoa/gdtoa.internal.h"
char*
g_dfmt(char *buf, double *d, int ndig, size_t bufsize)
{
static const FPI fpi0 = { 53, 1-1023-53+1, 2046-1023-53+1, 1, 0, Int_max };
char *b, *s, *se;
ULong bits[2], *L, sign;
int decpt, ex, i, mode;
#include "third_party/gdtoa/gdtoa_fltrnds.inc"
if (ndig < 0)
ndig = 0;
if (bufsize < (size_t)(ndig + 10))
return 0;
L = (ULong*)d;
sign = L[1] & 0x80000000L;
if ((L[1] & 0x7ff00000) == 0x7ff00000) {
/* Infinity or NaN */
if (bufsize < 10)
return 0;
if (L[1] & 0xfffff || L[0]) {
return stpcpy(buf, "NaN");
}
b = buf;
if (sign)
*b++ = '-';
return stpcpy(b, "Infinity");
}
if (L[0] == 0 && (L[1] ^ sign) == 0 /*d == 0.*/) {
b = buf;
if (L[1] & 0x80000000L)
*b++ = '-';
*b++ = '0';
*b = 0;
return b;
}
bits[0] = L[0];
bits[1] = L[1] & 0xfffff;
if ( (ex = (L[1] >> 20) & 0x7ff) !=0)
bits[1] |= 0x100000;
else
ex = 1;
ex -= 0x3ff + 52;
mode = 2;
if (ndig <= 0)
mode = 0;
i = STRTOG_Normal;
if (sign)
i = STRTOG_Normal | STRTOG_Neg;
s = gdtoa(fpi, ex, bits, &i, mode, ndig, &decpt, &se);
return __gdtoa_g__fmt(buf, s, se, decpt, sign, bufsize);
}