byte []到RubyString，用于JRuby Java Extension中的字符串xor

Question

I'm trying to implement a Java extension for JRuby to perform string xors. I'm just uncertain how to type cast a byte array into a RubyString :

public static RubyString xor(ThreadContext context,  IRubyObject self, RubyString x, RubyString y) {
    byte[] xBytes = x.getBytes();
    byte[] yBytes = y.getBytes();

    int length = yBytes.length < xBytes.length ? yBytes.length : xBytes.length;

    for(int i = 0; i < length; i++) {
        xBytes[i] = (byte) (xBytes[i] ^ yBytes[i]);
    }

    // How to return a RubyString with xBytes as its content?
}

Also, how would one perform the same operation in-place (ie x s value is updated)?

Answer 1

return context.runtime.newString(new ByteList(xBytes, false));

Answer 2

You'll first need to wrap the bytes in a ByteList : new ByteList(xBytes, false) . The last parameter ( Boolean copy ) dictates whether to wrap a copy of the Byte array.

To update the string in place, use [RubyString#setValue()][2] :

x.setValue(new ByteList(xBytes, false);
return x;

To return a new RubyString , you can pass that list to the current runtime's #newString() :

return context.runtime.newString(new ByteList(xBytes, false));