public void Subtract(LongNumber value)
{
VerifySameSize(value);
int index = size - 1;
while (index >= 0 && value.number[index] == 0)
{
index--;
}
UInt32 borrow = 0;
while (index >= 0)
{
UInt64 result = 0x100000000U + (UInt64)number[index] -
value.number[index] - borrow;
number[index] = (UInt32)result;
if (result >= 0x100000000U)
{
borrow = 0;
}
else
{
borrow = 1;
}
index--;
}
}
public void Add(LongNumber value)
{
VerifySameSize(value);
int index = size - 1;
while (index >= 0 && value.number[index] == 0)
{
index--;
}
UInt32 carry = 0;
while (index >= 0)
{
UInt64 result = (UInt64)number[index] +
value.number[index] + carry;
number[index] = (UInt32)result;
if (result >= 0x100000000U)
{
carry = 1;
}
else
{
carry = 0;
}
index--;
}
}
public string Print()
{
LongNumber temp = new LongNumber(maxDigits);
temp.Assign(this);
StringBuilder sb = new StringBuilder();
sb.Append(temp.number[0]);
sb.Append(System.Globalization.CultureInfo.CurrentCulture.NumberFormat.CurrencyDecimalSeparator);
int digitCount = 0;
while (digitCount < maxDigits)
{
temp.number[0] = 0;
temp.Multiply(100000);
sb.AppendFormat("{0:D5}", temp.number[0]);
digitCount += 5;
}
string result = sb.ToString();
int rest = maxDigits % 5;
if (rest != 0)
{
result = result.Substring(0, result.Length - (5 - rest));
}
return(result);
}
public void Assign(LongNumber value)
{
VerifySameSize(value);
for (int i = 0; i < size; i++)
{
number[i] = value.number[i];
}
}
private static async Task <string> CalculatePiPrecision(int precision, CancellationToken cancellationToken = default)
{
LongNumber x = new LongNumber(precision);
LongNumber y = new LongNumber(precision);
await x.ArcTan(16, 5, cancellationToken);
await y.ArcTan(4, 239, cancellationToken);
x.Subtract(y);
return(x.Print());
}
private void VerifySameSize(LongNumber value)
{
if (Object.ReferenceEquals(this, value))
{
throw new Exception("LongNumbers cannot operate on themselves");
}
if (value.size != this.size)
{
throw new Exception("LongNumbers must have the same size");
}
}
public async Task ArcTan(UInt32 multiplicand, UInt32 reciprocal, CancellationToken cancellationToken = default)
{
LongNumber X = new LongNumber(maxDigits, multiplicand);
X.Divide(reciprocal);
reciprocal *= reciprocal;
this.Assign(X);
LongNumber term = new LongNumber(maxDigits);
UInt32 divisor = 1;
bool subtractTerm = true;
while (true)
{
cancellationToken.ThrowIfCancellationRequested();
X.Divide(reciprocal);
term.Assign(X);
divisor += 2;
term.Divide(divisor);
if (term.IsZero())
{
break;
}
if (subtractTerm)
{
this.Subtract(term);
}
else
{
this.Add(term);
}
subtractTerm = !subtractTerm;
}
}
