126 lines
3.7 KiB
Java
126 lines
3.7 KiB
Java
/*
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* Copyright 2016 The Netty Project
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*
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* The Netty Project licenses this file to you under the Apache License,
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* version 2.0 (the "License"); you may not use this file except in compliance
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* with the License. You may obtain a copy of the License at:
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
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* WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
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* License for the specific language governing permissions and limitations
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* under the License.
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*/
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package io.netty.handler.codec.compression;
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import static java.util.Objects.requireNonNull;
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import io.netty.buffer.ByteBuf;
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import io.netty.util.ByteProcessor;
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import java.nio.ByteBuffer;
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import java.util.zip.Adler32;
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import java.util.zip.CRC32;
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import java.util.zip.Checksum;
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/**
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* {@link Checksum} implementation which can directly act on a {@link ByteBuf}.
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*
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* Implementations may optimize access patterns depending on if the {@link ByteBuf} is backed by a
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* byte array ({@link ByteBuf#hasArray()} is {@code true}) or not.
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*/
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abstract class ByteBufChecksum implements Checksum {
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private final ByteProcessor updateProcessor = value -> {
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update(value);
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return true;
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};
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static ByteBufChecksum wrapChecksum(Checksum checksum) {
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requireNonNull(checksum, "checksum");
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if (checksum instanceof ByteBufChecksum) {
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return (ByteBufChecksum) checksum;
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}
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if (checksum instanceof Adler32) {
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return new OptimizedByteBufChecksum<Adler32>((Adler32) checksum) {
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@Override
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public void update(ByteBuffer b) {
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checksum.update(b);
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}
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};
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}
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if (checksum instanceof CRC32) {
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return new OptimizedByteBufChecksum<CRC32>((CRC32) checksum) {
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@Override
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public void update(ByteBuffer b) {
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checksum.update(b);
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}
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};
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}
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return new SlowByteBufChecksum<>(checksum);
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}
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/**
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* @see #update(byte[], int, int)
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*/
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public void update(ByteBuf b, int off, int len) {
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if (b.hasArray()) {
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update(b.array(), b.arrayOffset() + off, len);
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} else {
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b.forEachByte(off, len, updateProcessor);
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}
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}
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private abstract static class OptimizedByteBufChecksum<T extends Checksum> extends SlowByteBufChecksum<T> {
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OptimizedByteBufChecksum(T checksum) {
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super(checksum);
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}
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@Override
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public void update(ByteBuf b, int off, int len) {
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if (b.hasArray()) {
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update(b.array(), b.arrayOffset() + off, len);
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} else {
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try {
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update(CompressionUtil.safeNioBuffer(b, off, len));
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} catch (Throwable cause) {
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throw new Error();
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}
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}
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}
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public abstract void update(ByteBuffer b);
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}
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private static class SlowByteBufChecksum<T extends Checksum> extends ByteBufChecksum {
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protected final T checksum;
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SlowByteBufChecksum(T checksum) {
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this.checksum = checksum;
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}
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@Override
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public void update(int b) {
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checksum.update(b);
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}
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@Override
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public void update(byte[] b, int off, int len) {
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checksum.update(b, off, len);
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}
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@Override
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public long getValue() {
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return checksum.getValue();
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}
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@Override
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public void reset() {
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checksum.reset();
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}
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}
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}
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