private Func <IEnumerable <byte>, IEnumerable <byte>, byte[]> PrepareOperationFunction(Lazy <bool?> firstIsBigger)
{
//If we have subtraction, change second number sign
if (Operation == BigNumber.Operation.Substraction)
{
m_Reader2.Info.IsNegative = !m_Reader2.Info.IsNegative;
}
//add numbers if they have the same sign
if (m_Reader1.Info.IsNegative == m_Reader2.Info.IsNegative)
{
m_ResultIsNegative = m_Reader1.Info.IsNegative;
return((f1, f2) => BigMath.Add(
f1, f2, m_PreviousHasCarry, out m_PreviousHasCarry));
}
if (!firstIsBigger.Value.HasValue)
{
return(null);
}
//we must use subtract
if (firstIsBigger.Value.Value)
{
m_ResultIsNegative = m_Reader1.Info.IsNegative;
return((f1, f2) =>
BigMath.Subtract(f1, f2, m_PreviousHasBorrow, out m_PreviousHasBorrow));
}
else
{
m_ResultIsNegative = m_Reader2.Info.IsNegative;
return((f1, f2) =>
BigMath.Subtract(f2, f1, m_PreviousHasBorrow, out m_PreviousHasBorrow));
}
}
public void AssertSubtractMethod10Minus1()
{
string val1 = "10";
string val2 = "1";
string results = BigMath.Subtract(val1, val2);
Assert.AreEqual("9", results);
}
public void AssertSubtractMethodLargeNumberToOne()
{
string val1 = "987654321987654321";
string val2 = "987654321987654320";
string results = BigMath.Subtract(val1, val2);
Assert.AreEqual("1", results);
}
public void AssertSubtractMethodLargeNumberToZero()
{
string val1 = "123456789";
string val2 = "123456789";
string results = BigMath.Subtract(val1, val2);
Assert.AreEqual("0", results);
}
public void SubtractionEqualsTest()
{
var a = ASCIIEncoding.Default.GetBytes("1000000");
var b = ASCIIEncoding.Default.GetBytes("1000000");
bool borrow;
var result = BigMath.Subtract(a, b, false, out borrow);
Assert.AreEqual("0000000", ASCIIEncoding.Default.GetString(result));
}
public static SqlNumber Subtract(SqlNumber a, SqlNumber b, int precision)
{
if (SqlNumber.IsNumber(a))
{
if (SqlNumber.IsNumber(b))
{
var context = new MathContext(precision);
var result = BigMath.Subtract(a.innerValue, b.innerValue, context);
return(new SqlNumber(SqlNumber.NumericState.None, result));
}
return(new SqlNumber(b.InverseState(), null));
}
return(a);
}
public void SubtractionShallHaventBorrowTest()
{
var a = ASCIIEncoding.Default.GetBytes("1001");
var b = ASCIIEncoding.Default.GetBytes("1000");
bool borrow;
var result = BigMath.Subtract(a, b, false, out borrow);
Assert.AreEqual(false, borrow);
a = ASCIIEncoding.Default.GetBytes("10");
b = ASCIIEncoding.Default.GetBytes("07");
result = BigMath.Subtract(a, b, borrow, out borrow).Concat(result).ToArray();
Assert.AreEqual("030001", ASCIIEncoding.Default.GetString(result));
}
public void SubtractionRandomNumbersTest()
{
var rand = new Random();
var rand2 = new Random();
for (int i = 0; i < 10; i++)
{
var a = rand.Next(0, Int32.MaxValue);
var b = rand.Next(0, Int32.MaxValue);
if (b > a)
{
var tmp = a;
b = a;
a = tmp;
}
string aString = a.ToString();
string bString = b.ToString();
if (aString.Length != bString.Length)
{
int length = Math.Max(aString.Length, bString.Length);
aString = aString.PadLeft(length, '0');
bString = bString.PadLeft(length, '0');
}
byte[] aBytes = Encoding.ASCII.GetBytes(aString);
byte[] bBytes = Encoding.ASCII.GetBytes(bString);
bool hasBorrow = false;
var result = BigMath.Subtract(aBytes, bBytes, false, out hasBorrow);
string number = Encoding.ASCII.GetString(result);
Assert.AreEqual((long)a - (long)b, long.Parse(number));
}
}
public void AssertStaticSubtractMethod()
{
var testLeft = "1";
var testRight = "1";
var testResult = BigMath.Subtract(testLeft, testRight);
}
