ByteBufChecksum Class — netty Architecture

Source Code

codec-compression/src/main/java/io/netty/handler/codec/compression/ByteBufChecksum.java lines 34–120

abstract class ByteBufChecksum implements Checksum {
    private final ByteProcessor updateProcessor = new ByteProcessor() {
        @Override
        public boolean process(byte value) throws Exception {
            update(value);
            return true;
        }
    };

    static ByteBufChecksum wrapChecksum(Checksum checksum) {
        ObjectUtil.checkNotNull(checksum, "checksum");
        if (checksum instanceof ByteBufChecksum) {
            return (ByteBufChecksum) checksum;
        }
        return new JdkByteBufChecksum(checksum);
    }

    /**
     * @see #update(byte[], int, int)
     */
    public void update(ByteBuf b, int off, int len) {
        if (b.hasArray()) {
            update(b.array(), b.arrayOffset() + off, len);
        } else {
            b.forEachByte(off, len, updateProcessor);
        }
    }

    private static class JdkByteBufChecksum extends ByteBufChecksum {
        protected final Checksum checksum;
        private byte[] scratchBuffer;

        JdkByteBufChecksum(Checksum checksum) {
            this.checksum = checksum;
        }

        @Override
        public void update(int b) {
            checksum.update(b);
        }

        @Override
        public void update(ByteBuf b, int off, int len) {
            if (b.hasArray()) {
                update(b.array(), b.arrayOffset() + off, len);
            } else if (checksum instanceof CRC32) {
                ByteBuffer byteBuffer = getSafeBuffer(b, off, len);
                ((CRC32) checksum).update(byteBuffer);
            } else if (checksum instanceof Adler32) {
                ByteBuffer byteBuffer = getSafeBuffer(b, off, len);
                ((Adler32) checksum).update(byteBuffer);
            } else {
                super.update(b, off, len);
            }
        }

        private ByteBuffer getSafeBuffer(ByteBuf b, int off, int len) {
            ByteBuffer byteBuffer = CompressionUtil.safeNioBuffer(b, off, len);
            int javaVersion = PlatformDependent.javaVersion();
            if (javaVersion >= 22 && javaVersion < 25 && byteBuffer.isDirect()) {
                // Work-around for https://bugs.openjdk.org/browse/JDK-8357145
                if (scratchBuffer == null || scratchBuffer.length < len) {
                    scratchBuffer = new byte[len];
                }
                ByteBuffer copy = ByteBuffer.wrap(scratchBuffer, 0, len);
                copy.put(byteBuffer).flip();
                return copy;
            }
            return byteBuffer;
        }

        @Override
        public void update(byte[] b, int off, int len) {
            checksum.update(b, off, len);
        }

        @Override
        public long getValue() {
            return checksum.getValue();
        }