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/*
 * Copyright (C) 2012 The Guava Authors
 *
 * 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 com.google.common.hash;

import static com.google.common.base.Preconditions.checkNotNull;
import static com.google.common.base.Preconditions.checkPositionIndexes;
import com.google.common.primitives.Chars;
import com.google.common.primitives.Ints;
import com.google.common.primitives.Longs;
import com.google.common.primitives.Shorts;
import java.nio.ByteBuffer;
import java.nio.ByteOrder;

/**
 *  Abstract {@link Hasher} that handles converting primitives to bytes using a scratch {@code
 *  ByteBuffer} and streams all bytes to a sink to compute the hash.
 *
 *  @author Colin Decker
 *
 * @deprecated The Google Guava Core Libraries are deprecated and will not be part of the AEM SDK after April 2023
 */
@Deprecated(since = "2022-12-01")
abstract class AbstractByteHasher extends AbstractHasher {

    private final ByteBuffer scratch = ByteBuffer.allocate(8).order(ByteOrder.LITTLE_ENDIAN);

    /**
     * Updates this hasher with the given byte.
     */
    protected abstract void update(byte b);

    /**
     * Updates this hasher with the given bytes.
     */
    protected void update(byte[] b) {
        update(b, 0, b.length);
    }

    /**
     * Updates this hasher with {@code len} bytes starting at {@code off} in the given buffer.
     */
    protected void update(byte[] b, int off, int len) {
        for (int i = off; i < off + len; i++) {
            update(b[i]);
        }
    }

    @Override
    public Hasher putByte(byte b) {
        update(b);
        return this;
    }

    @Override
    public Hasher putBytes(byte[] bytes) {
        checkNotNull(bytes);
        update(bytes);
        return this;
    }

    @Override
    public Hasher putBytes(byte[] bytes, int off, int len) {
        checkPositionIndexes(off, off + len, bytes.length);
        update(bytes, off, len);
        return this;
    }

    /**
     * Updates the sink with the given number of bytes from the buffer.
     */
    private Hasher update(int bytes) {
        try {
            update(scratch.array(), 0, bytes);
        } finally {
            scratch.clear();
        }
        return this;
    }

    @Override
    public Hasher putShort(short s) {
        scratch.putShort(s);
        return update(Shorts.BYTES);
    }

    @Override
    public Hasher putInt(int i) {
        scratch.putInt(i);
        return update(Ints.BYTES);
    }

    @Override
    public Hasher putLong(long l) {
        scratch.putLong(l);
        return update(Longs.BYTES);
    }

    @Override
    public Hasher putChar(char c) {
        scratch.putChar(c);
        return update(Chars.BYTES);
    }

    @Override
    public  Hasher putObject(T instance, Funnel funnel) {
        funnel.funnel(instance, this);
        return this;
    }
}