/*  snmcutdn.cpp  by K.Tsuru  */
//function ID=106,107
/**********************************************
SNumber class
CutDown()
It reduces size by removing unnecessary zeros.
***********************************************/
#ifndef SN_H
#include "sn.h"
#endif
// DETECT_IR = 3 in SNManager class
bool SNumber::cutDownTable[SNManager::DETECT_IR] = {DISABLE, ENABLE, ENABLE};

// function ID = 106
void SNumber::CutDown(uchar cd) {
    if(type == BIN_DEC) return;     // SDecimal always DISABLE.
    int tp = type & DETECT_IR;
#ifndef NDEBUG
assert(tp);
#endif
    if(cd == POP){
        if(pushCD & PUSH){
            pushCD &= ~PUSH;
            cutDownTable[tp] = (cutDownTable[tp] == ENABLE) ? DISABLE : ENABLE;
        }
    } else {    // here cd == DISABLE (false) or ENABLE(true)
//      if( cd != (cutDownTable[tp]){
        uchar temp = cutDownTable[tp] ? 1u : 0; // for the warning by visual c++ since ver 2.19
        if( cd != temp){
            cutDownTable[tp] = (cutDownTable[tp] == ENABLE) ? DISABLE : ENABLE;
            pushCD |= PUSH;
        }
    }
}
// function ID = 107
//It removes unnecessary zeros.
//necessary size = aHead+1
void SNumber::DoCutDown(){
    if(CutDown() == DISABLE) return;
    if( figure.size() <= minArraySize ) return;     //cannot reduce size
    if( 2u*(aHead+1) <= figure.size() ) valloc( aHead+1, 1);
}