src/org/kocakosm/pitaya/util/BaseEncoding.java
public byte[] decode(String in, int off, int len)
	{
		return decode(in.substring(off, off + len));
	}
public byte[] decode(String in, int off, int len)
	{
		return decode(in.substring(off, off + len));
	}
Decodes the specified range from the given encoded {@code String}
according to this {@code BaseEncoding}'s configuration. Decoding is
not case-sensitive when possible (namely for Base16, Base32 and
Base32Hex schemes).

@param in the input {@code String}.
@param off the input offset.
@param len the number of characters to decode.

@return the decoded data.

@throws NullPointerException if {@code in} is {@code null}.
@throws IndexOutOfBoundsException if {@code off} or {@code len} is
negative or if {@code off + len} is greater than {@code in}'s
length.
@throws IllegalArgumentException if the specified character range in
{@code in} is not a valid base-encoded {@code String} according
to this {@code BaseEncoding}'s configuration.