/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you 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 org.apache.flink.runtime.testutils.recordutils;

import java.io.IOException;

import org.apache.flink.api.common.typeutils.CompatibilityResult;
import org.apache.flink.api.common.typeutils.TypeSerializer;
import org.apache.flink.api.common.typeutils.TypeSerializerConfigSnapshot;
import org.apache.flink.core.memory.DataInputView;
import org.apache.flink.core.memory.DataOutputView;
import org.apache.flink.types.Record;


/**
 * Implementation of the (de)serialization and copying logic for the {@link Record}.
 */
public final class RecordSerializer extends TypeSerializer<Record> {
	
	private static final long serialVersionUID = 1L;

	private static final RecordSerializer INSTANCE = new RecordSerializer(); // singleton instance
	
	private static final int MAX_BIT = 0x80;	// byte where only the most significant bit is set
	
	// --------------------------------------------------------------------------------------------

	public static RecordSerializer get() {
		return INSTANCE;
	}
	
	/**
	 * Creates a new instance of the RecordSerializers. Private to prevent instantiation.
	 */
	private RecordSerializer() {}

	// --------------------------------------------------------------------------------------------
	
	@Override
	public boolean isImmutableType() {
		return false;
	}

	@Override
	public RecordSerializer duplicate() {
		// does not hold state, so just return ourselves
		return this;
	}
	
	@Override
	public Record createInstance() {
		return new Record(); 
	}

	@Override
	public Record copy(Record from) {
		return from.createCopy();
	}
	
	@Override
	public Record copy(Record from, Record reuse) {
		from.copyTo(reuse);
		return reuse;
	}
	
	@Override
	public int getLength() {
		return -1;
	}

	// --------------------------------------------------------------------------------------------
	
	@Override
	public void serialize(Record record, DataOutputView target) throws IOException {
		record.serialize(target);
	}

	@Override
	public Record deserialize(DataInputView source) throws IOException {
		return deserialize(new Record(), source);
	}
	
	@Override
	public Record deserialize(Record target, DataInputView source) throws IOException {
		target.deserialize(source);
		return target;
	}
	
	@Override
	public void copy(DataInputView source, DataOutputView target) throws IOException {
		int val = source.readUnsignedByte();
		target.writeByte(val);
		
		if (val >= MAX_BIT) {
			int shift = 7;
			int curr;
			val = val & 0x7f;
			while ((curr = source.readUnsignedByte()) >= MAX_BIT) {
				target.writeByte(curr);
				val |= (curr & 0x7f) << shift;
				shift += 7;
			}
			target.writeByte(curr);
			val |= curr << shift;
		}
		
		target.write(source, val);
	}

	@Override
	public boolean equals(Object obj) {
		if (obj instanceof RecordSerializer) {
			RecordSerializer other = (RecordSerializer) obj;
			return other.canEqual(this);
		} else {
			return false;
		}
	}

	@Override
	public boolean canEqual(Object obj) {
		return obj instanceof RecordSerializer;
	}

	@Override
	public int hashCode() {
		return RecordSerializer.class.hashCode();
	}

	@Override
	public TypeSerializerConfigSnapshot snapshotConfiguration() {
		throw new UnsupportedOperationException();
	}

	@Override
	public CompatibilityResult<Record> ensureCompatibility(TypeSerializerConfigSnapshot configSnapshot) {
		throw new UnsupportedOperationException();
	}
}