private static void SingleDivide(BigInteger leftSide, BigInteger rightSide, out BigInteger quotient, out BigInteger remainder)
{
if (rightSide.IsZero)
{
throw new DivideByZeroException();
}
DigitsArray remainderDigits = new DigitsArray(leftSide.m_digits);
remainderDigits.ResetDataUsed();
int pos = remainderDigits.DataUsed - 1;
ulong divisor = (ulong)rightSide.m_digits[0];
ulong dividend = (ulong)remainderDigits[pos];
DType[] result = new DType[leftSide.m_digits.Count];
leftSide.m_digits.CopyTo(result, 0, result.Length);
int resultPos = 0;
if (dividend >= divisor)
{
result[resultPos++] = (DType)(dividend / divisor);
remainderDigits[pos] = (DType)(dividend % divisor);
}
pos--;
while (pos >= 0)
{
dividend = ((ulong)(remainderDigits[pos + 1]) << DigitsArray.DataSizeBits) + (ulong)remainderDigits[pos];
result[resultPos++] = (DType)(dividend / divisor);
remainderDigits[pos + 1] = 0;
remainderDigits[pos--] = (DType)(dividend % divisor);
}
remainder = new BigInteger(remainderDigits);
DigitsArray quotientDigits = new DigitsArray(resultPos + 1, resultPos);
int j = 0;
for (int i = quotientDigits.DataUsed - 1; i >= 0; i--, j++)
{
quotientDigits[j] = result[i];
}
quotient = new BigInteger(quotientDigits);
}
private void ConstructFrom(byte[] array, int offset, int length)
{
if (array == null)
{
throw new ArgumentNullException("array");
}
if (offset > array.Length || length > array.Length)
{
throw new ArgumentOutOfRangeException("offset");
}
if (length > array.Length || (offset + length) > array.Length)
{
throw new ArgumentOutOfRangeException("length");
}
int estSize = length / 4;
int leftOver = length & 3;
if (leftOver != 0)
{
++estSize;
}
m_digits = new DigitsArray(estSize + 1, 0); // alloc one extra since we can't init -'s from here.
for (int i = offset + length - 1, j = 0; (i - offset) >= 3; i -= 4, j++)
{
m_digits[j] = (DType)((array[i - 3] << 24) + (array[i - 2] << 16) + (array[i - 1] << 8) + array[i]);
m_digits.DataUsed++;
}
DType accumulator = 0;
for (int i = leftOver; i > 0; i--)
{
DType digit = array[offset + leftOver - i];
digit = (digit << ((i - 1) * 8));
accumulator |= digit;
}
m_digits[m_digits.DataUsed] = accumulator;
m_digits.ResetDataUsed();
}
/// <summary>
/// Copy constructor, doesn't copy the digits parameter, assumes <code>this</code> owns the DigitsArray.
/// </summary>
/// <remarks>The <paramef name="digits" /> parameter is saved and reset.</remarks>
/// <param name="digits"></param>
private BigInteger(DigitsArray digits)
{
digits.ResetDataUsed();
this.m_digits = digits;
}
/// <summary>
/// Creates a BigInteger with the value of the operand. Can never be negative.
/// </summary>
/// <param name="number">A unsigned long.</param>
public BigInteger(ulong number)
{
m_digits = new DigitsArray((8 / DigitsArray.DataSizeOf) + 1, 0);
while (number != 0 && m_digits.DataUsed < m_digits.Count)
{
m_digits[m_digits.DataUsed] = (DType)(number & DigitsArray.AllBits);
number >>= DigitsArray.DataSizeBits;
m_digits.DataUsed++;
}
m_digits.ResetDataUsed();
}
