package com.jcoglan.websocket;

import java.io.IOException; import org.jruby.Ruby; import org.jruby.RubyClass; import org.jruby.RubyModule; import org.jruby.RubyObject; import org.jruby.RubyString; import org.jruby.anno.JRubyMethod; import org.jruby.runtime.ObjectAllocator; import org.jruby.runtime.ThreadContext; import org.jruby.runtime.builtin.IRubyObject; import org.jruby.runtime.load.BasicLibraryService;

public class WebsocketMaskService implements BasicLibraryService {

private Ruby runtime;

public boolean basicLoad(Ruby runtime) throws IOException {
    this.runtime = runtime;

    RubyModule websocket = runtime.defineModule("WebSocket");
    RubyClass webSocketMask = websocket.defineClassUnder("Mask", runtime.getObject(), getAllocator());

    webSocketMask.defineAnnotatedMethods(WebsocketMask.class);
    return true;
}

ObjectAllocator getAllocator() {
    return new ObjectAllocator() {
        public IRubyObject allocate(Ruby runtime, RubyClass rubyClass) {
            return new WebsocketMask(runtime, rubyClass);
        }
    };
}

public class WebsocketMask extends RubyObject {
    public WebsocketMask(final Ruby runtime, RubyClass rubyClass) {
        super(runtime, rubyClass);
    }

    @JRubyMethod
    public IRubyObject mask(ThreadContext context, IRubyObject payload, IRubyObject mask) {
        if (mask.isNil()) return payload;

        byte[] payload_a = ((RubyString)payload).getBytes();
        byte[] mask_a    = ((RubyString)mask).getBytes();
        int i, n         = payload_a.length;

        if (n == 0) return payload;

        for (i = 0; i < n; i++) {
            payload_a[i] ^= mask_a[i % 4];
        }
        return RubyString.newStringNoCopy(runtime, payload_a);
    }
}

}