reactos/sdk/lib/crt/stdlib/fcvtbuf.c

126 lines
3.3 KiB
C

#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#include <float.h>
#include <math.h>
#include <malloc.h>
// #include <msvcrt/locale.h>
// replace fjgpp fcvtbuf from project http://www.jbox.dk/sanos/source/lib/fcvt.c.html
// with small modification's to match ReactOS arch
// Floating point to string conversion routines
//
// Copyright (C) 2002 Michael Ringgaard. All rights reserved.
//
// Redistribution and use in source and binary forms, with or without
// modification, are permitted provided that the following conditions
// are met:
//
// 1. Redistributions of source code must retain the above copyright
// notice, this list of conditions and the following disclaimer.
// 2. Redistributions in binary form must reproduce the above copyright
// notice, this list of conditions and the following disclaimer in the
// documentation and/or other materials provided with the distribution.
// 3. Neither the name of the project nor the names of its contributors
// may be used to endorse or promote products derived from this software
// without specific prior written permission.
//
// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
// ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
// IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
// ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE
// FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
// DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
// OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
// HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
// LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
// OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
// SUCH DAMAGE.
//
//#include <math.h>
#define CVTBUFSIZE 2 * DBL_MAX_10_EXP + 10
static char *cvt(double arg, int ndigits, int *decpt, int *sign, char *buf, int eflag)
{
int r2;
double fi, fj;
char *p, *p1;
if (ndigits >= CVTBUFSIZE - 1) ndigits = CVTBUFSIZE - 2;
r2 = 0;
*sign = 0;
p = &buf[0];
if (arg < 0)
{
*sign = 1;
arg = -arg;
}
arg = modf(arg, &fi);
p1 = &buf[CVTBUFSIZE];
if (fi != 0)
{
p1 = &buf[CVTBUFSIZE];
while (fi != 0)
{
fj = modf(fi / 10, &fi);
*--p1 = (int)((fj + .03) * 10) + '0';
r2++;
}
while (p1 < &buf[CVTBUFSIZE]) *p++ = *p1++;
}
else if (arg > 0)
{
while ((fj = arg * 10) < 1)
{
arg = fj;
r2--;
}
}
p1 = &buf[ndigits];
if (eflag == 0) p1 += r2;
*decpt = r2;
if (p1 < &buf[0])
{
buf[0] = '\0';
return buf;
}
while (p <= p1 && p < &buf[CVTBUFSIZE])
{
arg *= 10;
arg = modf(arg, &fj);
*p++ = (int) fj + '0';
}
if (p1 >= &buf[CVTBUFSIZE])
{
buf[CVTBUFSIZE - 1] = '\0';
return buf;
}
p = p1;
*p1 += 5;
while (*p1 > '9')
{
*p1 = '0';
if (p1 > buf)
++*--p1;
else
{
*p1 = '1';
(*decpt)++;
if (eflag == 0)
{
if (p > buf) *p = '0';
p++;
}
}
}
*p = '\0';
return buf;
}
char *fcvtbuf(double arg, int ndigits, int *decpt, int *sign, char *buf)
{
return cvt(arg, ndigits, decpt, sign, buf, 0);
}