/*
 * Copyright 2009-2010 Yuichiro Moriguchi
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package net.morilib.lisp.nio;

import java.nio.ByteBuffer;

import net.morilib.lisp.ConsIterator;
import net.morilib.lisp.Datum;
import net.morilib.lisp.Environment;
import net.morilib.lisp.LispMessage;
import net.morilib.lisp.SExpressionDatum;
import net.morilib.lisp.subr.SubrUtils;
import net.morilib.lisp.subr.UnaryArgs;
import net.morilib.util.primitive.ByteArrayVector;
import net.morilib.util.primitive.ByteVector;

/**
 *
 *
 * @author MORIGUCHI, Yuichiro 2011/06/12
 */
public class U8ListToBlob extends UnaryArgs {

	/* (non-Javadoc)
	 * @see net.morilib.lisp.subr.UnaryArgs#execute(net.morilib.lisp.Datum, net.morilib.lisp.Environment, net.morilib.lisp.LispMessage)
	 */
	@Override
	protected Datum execute(Datum c1a, Environment env,
			LispMessage mesg) {
		if(c1a instanceof SExpressionDatum) {
			ConsIterator itr = new ConsIterator(c1a);
			ByteVector a = new ByteArrayVector();

			while(itr.hasNext()) {
				int b = SubrUtils.nextSmallInt(itr, -1, mesg);

				if(b > 255 || b < 0) {
					throw mesg.getError("err.srfi74.require.octet",
							"" + b);
				}
				a.addByte((byte)b);
			}
			SubrUtils.checkTerminated(itr, c1a, mesg);
			return new LispBlob(ByteBuffer.wrap(a.toByteArray()));
		} else {
			throw mesg.getError("err.list", c1a);
		}
	}

}
