/*  sifismul.cpp  by K.Tsuru  */
// function ID = 424    BRADIX
/*****************************************
SInteger class
It multiplies SInteger 'm' by ulong integer 'x'.
result = m*x for x < ULONG_MAX
******************************************/
#ifndef SN_H
#include "sn.h"
#endif

void IsMult(const SInteger& m, ulong x, SInteger& result){
    if(!m.Sign(424) || x == 1UL){   result = m;     return;     }
    if(x == 0){ result.SetZero();   return; }
    const ulong mt = m.SlOpMaxValue();
    if(x > mt){
        SInteger s(x);
        result = NLLMult(m, s);
        return;
//      m.SetError(m.OUT_OF_RANGE,"IsMult", 424);
    }
    uint rh = m.Head(), rt = m.Tail();
    if( &m != &result ){
    //When &m == &result do not execute/not need.
        if(result.Size() < rh+1u) result.valloc(rh+1u, -1);
    //It fills the not substituted part with zero.
        if(rt) result.figure.clear(result.aTail, rt-1u);
        result.figure.clear(rh+1u);
    }

    const fType* mv = m.ReadFigures();
    fType* rv = result.figure.Elements();
#ifndef NDEBUG
result.figure(rh);  m.figure(rh);
#endif
    register uint i;
    ulong t = 0, rdx1 = (ulong)BRADIX1;

    for(i = rt; i <= rh; i++) {
        t += (ulong)mv[i]*x;
        rv[i] = fType(t & rdx1);
        t >>= BRADIX_BITS;
    }

    if(t){//carry to the top
        if(t < BRADIX){
            rh++;
            result.Reserve(rh); // result.size() >= rh+i+1
            result.figure[rh] = (fType)t;
            rv = result.figure.Elements();
        } else {//It normalizes the carry and copy to the top.
            fType temp[5];
            i = 0;
            while(t){
                temp[i] = fType(t & rdx1);
                t >>= BRADIX_BITS;      i++;
            }
            result.Reserve(rh+i);   // result.size() >= rh+i+1
            rv = result.figure.Elements();
            memcpy( (rv+rh+1u), temp, i*sizeof(fType));
            rh += i;
        }
    }
    result.aHead = rh;
    while( !rv[rt] ) rt++;
    result.aTail = rt;
#ifndef NDEBUG
result.figure(rh);
#endif
    result.SetSign(m.RawSign());
    if( 2u*(result.aHead+1) <= result.figure.size() ) result.DoCutDown();
}