/*  sdmround.cpp  by K.Tsuru  */
// function ID = 342    DRADIX, BRADIX
/******************************************************************************
SDouble class
It provides the rounding off to the last effective figure.
At the top of hidden figures it rounds up numbers of radix/2 and above and drops
anything under radix/2.It is used in the output function, etc.
It executes in the case size==MaxSize(). It does not use CurrentMaxSize().
When std==1 it converts into the standard from.
default : std = 1
*******************************************************************************/
#ifndef SN_H
#include "sn.h"
#endif

SDouble& SDouble::Round(int std){
//conversion into standard form, SDouble only
    if( (Type() == REAL) && (std & STD_REF) ) StdReform(342);
// 0.v[1] ...... v[eff]v[hdn]
    uint i, eff = MaxSize() - Hidden() -1u, rnd;
    if(aHead <= eff) return *this;  //It has no hidden figure including 0.
    rnd = eff + 1u;                 //top position of the hidden figures

    if( figure(rnd) >= Radix()/2 ){
        figure[rnd-1]++;
        if(figure(rnd-1) >= Radix()) Normalize();
        if(figure(0) && (Type() == REAL)){
            // 0.99999....D^e --> 1.0000....D^e --> 0.1000.... D^(e+1)
            SetRdxExp(rdxExp+1);    ShiftArray(1);
        }
    }
//It cuts down the hidden figures.
    for(i = rnd; i<= aHead; i++) figure[i] = 0;
    if(aTail >= rnd){
        //It becomes zero by cutting down in the fixed point mode.
        SetZero();  return *this;
    }
//It gets the figure positions."aTail" is not changed.
    i = rnd-1;
    const fType* fp = figure.Elements();
    while( !fp[i] ) i--;
#ifndef NDEBUG
figure(i);
#endif
    aHead = i;

//It converts into the standard form again for the reduction of the size, etc.
//0.abcd efgh 0000 .... 0000 hhhh hhhh --> 0.abcd efgh 0000 .... 0000
    if( (Type() == REAL) && (std & STD_REF) ) StdReform(342);
    return *this;
}