/* cheap ecvt replacement
Copyright (C) 1998,2000,2007 Free Software Foundation, Inc.
This file is part of Gforth.
Gforth is free software; you can redistribute it and/or
modify it under the terms of the GNU General Public License
as published by the Free Software Foundation; either version 2
of the License, or (at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111, USA.
*/
#include <stdio.h>
#include "config.h"
#include <math.h>
extern double floor(double);
extern double pow10(double);
#define MAXCONV 0x40
char scratch[MAXCONV];
char* ecvt(double x, int len, int* exp, int* sign)
{
int i, j;
double z;
if (isnan(x)) {
*sign=0;
*exp=0;
return "nan";
}
if (isinf(x)) {
*sign=0; /* this mimics the glibc ecvt */
*exp=0;
if (x<0)
return "-inf";
else
return "inf";
}
if(len > (MAXCONV-1)) len = MAXCONV-1;
if(x<0)
{
*sign = 1;
x = -x;
}
else
{
*sign = 0;
}
if(x==0)
*exp=-1;
else
*exp=(int)floor(log10(x));
x = x / pow10((double)*exp);
*exp += 1;
for(i=0; i < len; i++)
{
z=floor(x);
if(z<0) z = 0;
scratch[i]='0'+(char)((int)z);
x = (x-z)*10;
}
if((x >= 5) && i)
{
for(j=i-1; j>=0; j--)
{
if(scratch[j]!='9')
{
scratch[j]+=1; break;
}
else
{
scratch[j]='0';
}
}
if(j<0)
{
scratch[0]='1';
*exp += 1;
}
}
scratch[i]='\0';
return scratch;
}
#ifdef TEST
int main(int argc, char ** argv)
{
int a, b;
char * conv=ecvt(9e0,20,&a,&b);
printf("ecvt Test: %f -> %s, %d, %d\n",9e0,conv,a,b);
}
#endif
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