/*  srmeffig.cpp  by K.Tsuru  */
// function ID = 008
/**************************************
RealSize class
1.destructor
2.Set the numbers of effective figures.
***************************************/
#ifndef SN_H
#include "sn.h"
#endif

RealSize::~RealSize(){
    if(size[0]) Restore();  // restore effective figures
}
uint RealSize::SetEffFig(uint fig, int proper){
    if(proper & PREF_SPEED) preferSpeed = true;
    if(!fig){   //It restores to the previous values.
        if(size[0] == 0) SetError(SET_EFF_FIG, "No data", 8);
        Restore();
        return effFigures;
    }
//It saves present figures and size.
    if(size[0] != 0) SetError(SET_EFF_FIG, "Save data twice", 8);
    Save();
    if(effFigures == fig) return effFigures;

//necessary size including hidden figures and figure[0]
    uint oldsz = effFigures + hidden + 1u, hdn;
    int decr_fig = 0;
    //When the number of hidden figures increases by adding hidden figures
    //it decreases by "decr_fig" figures.
    hidden = HiddenSize(fig);
    hdn = HiddenSize(fig+hidden+1u);
    if( (hdn > hidden) && !(proper & TEMP_EXTEND)){
        fig -= hdn;     decr_fig = (int)hdn;
    }
    uint sz = ceilpow2(fig);
    while(decr_fig && (fig + hidden + 1u < sz)){
    //It restores the decreased figures as much as possible.
        fig++;      decr_fig--;
    }
    if( sz <= minArraySize ){
        sz = 2u*minArraySize;
        effFigures = sz - hidden -1u;
    } else if( sz > MaxArraySize() ){
        if(!(proper & TEMP_EXTEND)) SetError(SET_EFF_FIG, "Effective figures is too large.", -8);
//Because there is functions which temporally increases the effective figures
//it decreases the effective figures a little.
        sz = MaxArraySize() - 8u;
        effFigures = sz - hidden -1u;
        proper = 0;
    } else effFigures = fig;
/****************************************************************
It provides a proper value of effFigures which is efficient for
FFT multiplication and memory.It is desirable to adopt the value
of CurrentMaxSize()(=effFigures+hidden+1u) as power of two because
the upper part is taken one figure larger in DDMult().
example :
sz = CurrentMaxSize() = 128, effFigures = 125, hidden = 2.
Excluding the first zero (128-1)/2+1=64(= 2^6) figures are passed
to LLMult().
*****************************************************************/
    sz = effFigures + hidden +1u;
    if(proper & PROPER){
        sz = ceilpow2(sz);
        hidden = HiddenSize(sz- hidden -1u);
        effFigures = sz - hidden -1u;
    }
/*
In the fixed point mode(reduceMaxSize == DISABLE, using the doubling effective
figures method etc) it changes the value of maxSize when the present size is
greater than the previous one only.
*/
    if( (reduceMaxSize == ENABLE) || (sz > oldsz) ) SetMaxSize();

    return effFigures;
}