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/* GDCHART 0.10.0dev PRICE_CONV.C 2 Nov 2000 */
/* Copyright Bruce Verderaime 1998, 1999, 2000 */
/*
* - price as float to a string (ostensibly for printing)
*/
#include <stdlib.h>
#include <stdio.h>
#include <ctype.h>
#include <math.h>
/* ----------------------------------------------------------------- */
/* -- convert a float to a printable string, in form: -- */
/* -- W N/D -- */
/* -- where W is whole, N is numerator, D is denominator -- */
/* -- the frac N/D is one of 2nds, 4,8,16,32,64,128,256ths -- */
/* -- if cannot convert, return str of the float -- */
/* ----------------------------------------------------------------- */
#define EPSILON ((1.0/256.0)/2.0)
#define GET_DEC(x) ( (x) - (float)(int)(x) )
char*
price_to_str( float price,
int *numorator,
int *demoninator,
int *decimal,
char *fltfmt ) // printf fmt'ing str
{
static char rtn[64];
int whole = (int)price;
float dec = GET_DEC( price ),
numr;
/* float pow( double, double ); */
// caller doesn't want fractions
if( fltfmt )
{
sprintf( rtn, fltfmt, price );
*numorator = *demoninator = *decimal = 0;
return rtn;
}
numr = dec * 256;
/* check if we have a perfect fration in 256ths */
{
float rdec = GET_DEC( numr );
if( rdec < EPSILON )
; /* close enough to frac */
else if( (1-rdec) < EPSILON ) /* just over but close enough */
++numr;
else /* no frac match */
{
sprintf( rtn, "%f", price );
*numorator = *demoninator = *decimal = 0;
return rtn;
}
}
/* now have numr 256ths */
/* resolve down */
if( numr != 0 )
{
int cnt = 8;
while( (float)(numr)/2.0 == (float)(int)(numr/2) )
{
numr /= 2;
--cnt;
}
/* don't want both whole AND numerator to be - */
if( whole<0 && numr<0.0 )
numr = -numr;
*numorator = (int)numr;
*demoninator = (int)pow(2.0, (float)cnt);
*decimal = whole;
sprintf( rtn, "%d %d/%d", whole,
(int)numr,
*demoninator );
}
else
{
*numorator = *demoninator = 0;
*decimal = whole;
sprintf( rtn, "%d", whole );
}
return rtn;
}
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