StringZMapMarshaller.java

/*
 * Copyright 2016 higherfrequencytrading.com
 *
 * 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.openhft.lang.io.serialization.impl;

import net.openhft.lang.io.Bytes;
import net.openhft.lang.io.serialization.CompactBytesMarshaller;
import net.openhft.lang.model.constraints.Nullable;

import java.io.DataInputStream;
import java.io.DataOutputStream;
import java.io.IOException;
import java.io.StreamCorruptedException;
import java.util.LinkedHashMap;
import java.util.Map;
import java.util.zip.Deflater;
import java.util.zip.DeflaterOutputStream;
import java.util.zip.InflaterInputStream;

/**
 * Created by peter.lawrey on 24/10/14.
 */
public enum StringZMapMarshaller implements CompactBytesMarshaller<Map<String, String>> {
    FAST(Deflater.BEST_SPEED),
    COMPACT(Deflater.BEST_COMPRESSION),
    INSTANCE(Deflater.DEFAULT_STRATEGY);

    private static final long NULL_SIZE = -1;
    private final int level;

    StringZMapMarshaller(int level) {
        this.level = level;
    }

    @Override
    public byte code() {
        return STRINGZ_MAP_CODE;
    }

    @Override
    public void write(Bytes bytes, Map<String, String> kvMap) {
        if (kvMap == null) {
            bytes.writeStopBit(NULL_SIZE);
            return;
        }

        bytes.writeStopBit(kvMap.size());
        long position = bytes.position();
        bytes.clear();
        bytes.position(position + 4);
        DataOutputStream dos = new DataOutputStream(
                new DeflaterOutputStream(bytes.outputStream(), new Deflater(level)));
        try {
            for (Map.Entry<String, String> entry : kvMap.entrySet()) {
                dos.writeUTF(entry.getKey());
                dos.writeUTF(entry.getValue());
            }
            dos.close();
        } catch (IOException e) {
            throw new IllegalStateException(e);
        }
        bytes.writeUnsignedInt(position, bytes.position() - position - 4);
    }

    @Override
    public Map<String, String> read(Bytes bytes) {
        return read(bytes, null);
    }

    @Override
    public Map<String, String> read(Bytes bytes, @Nullable Map<String, String> kvMap) {
        long size = bytes.readStopBit();
        if (size == NULL_SIZE)
            return null;
        if (size < 0 || size > Integer.MAX_VALUE)
            throw new IllegalStateException("Invalid length: " + size);

        long length = bytes.readUnsignedInt();
        if (length < 0 || length > Integer.MAX_VALUE)
            throw new IllegalStateException(new StreamCorruptedException());
        long position = bytes.position();
        long end = position + length;

        long limit = bytes.limit();
        bytes.limit(end);

        DataInputStream dis = new DataInputStream(new InflaterInputStream(bytes.inputStream()));
        if (kvMap == null) {
            kvMap = new LinkedHashMap<String, String>();

        } else {
            kvMap.clear();
        }
        try {
            for (int i = 0; i < size; i++) {
                String key = dis.readUTF();
                String value = dis.readUTF();
                kvMap.put(key, value);
            }
            dis.close();
        } catch (IOException e) {
            throw new IllegalStateException(e);
        }
        bytes.position(end);
        bytes.limit(limit);
        return kvMap;
    }
}