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/*
 * Copyright 2015 Odnoklassniki Ltd, Mail.Ru Group
 *
 * 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 one.nio.mem;

import one.nio.util.Hash;

public class OffheapBlobMap extends OffheapMap {
    protected static final int KEY_OFFSET = HEADER_SIZE + 4;

    public OffheapBlobMap(int capacity) {
        super(capacity, 0);
    }

    @Override
    public byte[] keyAt(long entry) {
        int keyLength = (int) (unsafe.getLong(entry + HASH_OFFSET) >>> 32);
        byte[] key = new byte[keyLength];
        unsafe.copyMemory(null, entry + KEY_OFFSET, key, byteArrayOffset, keyLength);
        return key;
    }

    @Override
    protected long hashCode(byte[] key) {
        int xxhash = Hash.xxhash(key, byteArrayOffset, key.length);
        return (long) key.length << 32 | (xxhash & 0xffffffffL);
    }

    @Override
    protected boolean equalsAt(long entry, byte[] key) {
        return DirectMemory.compare(null, entry + KEY_OFFSET, key, byteArrayOffset, key.length);
    }

    @Override
    protected byte[] valueAt(long entry) {
        int keyLength = (int) (unsafe.getLong(entry + HASH_OFFSET) >>> 32);
        int valueLength = sizeOf(entry);
        byte[] value = new byte[valueLength];
        unsafe.copyMemory(null, entry + KEY_OFFSET + keyLength, value, byteArrayOffset, valueLength);
        return value;
    }

    @Override
    protected void setValueAt(long entry, byte[] value) {
        int keyLength = (int) (unsafe.getLong(entry + HASH_OFFSET) >>> 32);
        int valueLength = value.length;
        unsafe.putInt(entry + HEADER_SIZE, valueLength);
        unsafe.copyMemory(value, byteArrayOffset, null, entry + KEY_OFFSET + keyLength, valueLength);
    }

    @Override
    protected long allocateEntry(byte[] key, long hashCode, int size) {
        long entry = unsafe.allocateMemory(KEY_OFFSET + key.length + size);
        unsafe.copyMemory(key, byteArrayOffset, null, entry + KEY_OFFSET, key.length);
        return entry;
    }

    @Override
    protected void destroyEntry(long entry) {
        unsafe.freeMemory(entry);
    }

    @Override
    protected int sizeOf(long entry) {
        return unsafe.getInt(entry + HEADER_SIZE);
    }

    @Override
    protected int sizeOf(byte[] value) {
        return value.length;
    }
}