I am trying to convert an input buffer (byte array) containing data that generated with a C# application to java data types. I have some issue with C#'s Decimal
dataType.
C# example:
decimal decimalValue = 20.20M;
//converting a Decimal value to 4 integer vlaues
int[] intPieces= Decimal.GetBits(decimalValue); //{2020,0,0,131072}
//using native constructor to rebuild value
Decimal newDecimalValue = new decimal(intPieces); //20.20
Console.WriteLine("DecimalValue is " + newDecimalValue);
but there is no Decimal
( and also no Decimal(int[] bits) constructor ) in java.
C# Decimal Constructor (Int32[]) documention.
In Java, you'd use BigDecimal
. That's not quite the same type, but it's reasonably close.
You just need to reconstruct the 96-bit integer as a BigInteger
, then scale it and optionally negate it:
import java.math.BigDecimal;
import java.math.BigInteger;
public class Test {
public static void main(String[] args) {
int[] parts = { 2020, 0, 0, 131072 };
BigInteger integer = BigInteger.valueOf(parts[2] & 0xffffffffL).shiftLeft(32)
.add(BigInteger.valueOf(parts[1] & 0xffffffffL )).shiftLeft(32)
.add(BigInteger.valueOf(parts[0] & 0xffffffffL));
BigDecimal decimal = new BigDecimal(integer, (parts[3] & 0xff0000) >> 16);
if (parts[3] < 0) // Bit 31 set
{
decimal = decimal.negate();
}
System.out.println(decimal);
}
}
Output:
20.20
The masking when constructing the BigInteger
parts is there to effectively treat the values as unsigned - performing a bitwise AND with a long
with the top 32 bits clear and the the bottom 32 bits set, we're constructing the same numeric value you'd get by casting each int
to uint
in C#.
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