/*  dbl2bdec.cpp  by K.Tsuru  */
/*************************************************
For |x| < BRADIX double x --> SDecimal array
In "snum.h" FigBlock is defined by
  typedef NCBlock<fType> FigBlock;
Associate function for SDouble and SDecimal classes
**************************************************/
#ifndef SN_H
#include "sn.h"
#endif

int doubleToBinDec(double x, FigBlock& res, uint *size){
    if(res.size() == 0){
        *size = 0;  return -2;
    }
// x == 0.0 ?
    if(x == 0.0){
        res.clear();
        *size = 1u;
        return 0;
    }
    double dp = fabs(x);
    if(dp >= BRADIX) return -1;
    int e;

    frexp(dp, &e);  // dp = y*2^e
    uint sz = (abs(e)+DOUBLE_BITS)/BRADIX_BITS + 2u;
    if( sz > res.size() ) sz = res.size();
    res.clear();
    uint j = 0;
    int f = 0;
// can be converted exactly to binary
    while(dp < 1.0){
        dp *= BRADIX;   j++;
    }
    for(; j < sz; j++){
        res[j] = (fType)dp;
        f++;
        dp -= (double)res[j];
        if(dp == 0.0) break;
        dp *= BRADIX;
    }
    *size = min(j+1u, sz);
    if(dp > 0.0) f = -2;    // not enough figures
    return f;
}