Re: convert byte array to hex string using BigInteger
On Thu, 20 Jun 2013 15:32:56 +0200, Laura Schmidt <email@example.com>
On 06/20/2013 03:09 PM, rossum wrote:
This is a case of RTFM. The Javadocs for BigInteger(byte) tell you
that it expects the byte array in two's complement representation, so
a leading 1 bit is interpreted as a negative number. You need a
public BigInteger(int signum, byte magnitude)
You are right, sorry.
Now I get a hex string without sign. But now the decode method does not
return the original bytes anymore:
private byte  hex_decode (String val)
BigInteger b = new BigInteger (val,16);
byte  t = b.toByteArray();
There is no other constructor for byte arrays.
And I don't really understand why it doesn't return the original byte array.
Again, you need to look at the Javadoc. That tells you toByteArray()
returns the two's complement representation of the BigInt.
Either convert the two's complement or write your own hex_decode(), it
isn't that difficult.
As a minor point, you should follow the Java naming conventions:
hexEncode() and hexDecode(). Underscores are more C++ than Java.
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