/*  siosiand.cpp  by K.Tsuru  */
// function ID = 408   DRADIX, BRADIX
/*******************************************
SInteger class
It provides the bit "and" oparattion m & n.
********************************************/
#ifndef SN_H
#include "sn.h"
#endif
SInteger operator&(const SInteger& m, const SInteger& n){
    if( m.Sign(408) == 0) return m; // return 0.0;
    if( n.Sign(408) == 0) return n;

    const fType* mv;
    const fType* nv;
    uint t, h;
    mv = m.ReadFigures();
    nv = n.ReadFigures();
    h = max(m.Head(), n.Head());    // aHead --> Head() since ver 2.191
    t = min(m.Tail(), n.Tail());

    SInteger result;

    if( h < t ) {
        result.SetZero();   return result;  // ver.2.17
    }
    result.valloc(h + 1u, -1);
    result.figure.clear(0, t);
    result.figure.clear(h + 1u);
    fType* rv = result.figure.Elements();
    for(register uint i = t; i <= h; i++){
        rv[i] = mv[i] & nv[i];
    }
    while( !rv[t] && t <= h ) t++;
    if( h < t ) {   // Here rv[h] = 0 and t = h + 1 i.e. result = 0.
        result.SetZero();   return result;  // ver.2.17
    }

// Below result != 0.
    result.aTail = t;
    while( !rv[h] && h > t ) h--;
    result.aHead = h;

    result.SetSign(1);
// It reduces the size if possible.
    if( 2u * (result.aHead + 1) <= result.figure.size() ) result.DoCutDown();
    return result;
}