std::pair<integer, integer> integer::divide(integer R, const integer& D)
{ if(D == (integer)0 ) throw new std::overflow_error("Division by zero!");
integer R_initial = R;
integer Q = 0;
integer guess = 1;
integer test;
//std::stack<integer> stack;
size_t guess_p = 0;
if(D > R) return std::pair<integer, integer>(Q, R);
while((D << guess_p) <= R)
{ //stack.push(guess << guess_p);
//std::cout << (guess << guess_p) << std::endl;
guess_p = guess_p+std::numeric_limits<unsigned int>::digits;
//guess = guess << (size_t)std::numeric_limits<unsigned int>::digits; //bitshift it up by a whole digit
}
//guess = stack.top();
//std::cout << guess << std::endl;
while(guess_p < std::numeric_limits<unsigned int>::max())
{ test = (D << guess_p);
if(test <= R)
{ Q = (Q + (guess << guess_p));
R = (R - test);
}
--guess_p;
}
/*
while(!stack.empty())
{ guess = stack.top();
stack.pop();
assert(guess.data.back() == 1U);
guess.data.back() = guess.data.back()<< (std::numeric_limits<unsigned int>::digits -1); //bitshift high digit up by 31 (nominally) bits
for(size_t i = 0; i <= (std::numeric_limits<unsigned int>::digits - 1); ++i)
{ test = guess * D;
//std::cout << guess << std::endl;
if(test <= R)
{ Q = Q + guess;
R = R - test;
//test = guess * D;
}
guess.data.back() = guess.data.back()>>1; //bitshift back down 1 bit.
} }
*/
assert(R<D);
Q.minimize();
R.minimize();
return std::pair<integer, integer>(Q, R);
}
