Crc32cSse42Provider.java

/**
 * Copyright 2016 Yahoo Inc.
 *
 * 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.yahoo.pulsar.checksum.utils;

import java.util.EnumSet;

import com.scurrilous.circe.Hash;
import com.scurrilous.circe.HashParameters;
import com.scurrilous.circe.HashSupport;
import com.scurrilous.circe.StatelessHash;
import com.scurrilous.circe.crc.Sse42Crc32C;
import com.scurrilous.circe.impl.AbstractHashProvider;
import com.scurrilous.circe.params.CrcParameters;

public final class Crc32cSse42Provider extends AbstractHashProvider<HashParameters> {

    // Default chunks of 32 KB, then 4 KB, then 512 bytes
    private static final int[] DEFAULT_CHUNK = new int[] { 4096, 512, 64 };

    public Crc32cSse42Provider() {
        super(HashParameters.class);
    }

    @Override
    protected EnumSet<HashSupport> querySupportTyped(HashParameters params) {
        if (isCrc32C(params) && Sse42Crc32C.isSupported())
            return EnumSet.allOf(HashSupport.class);
        return EnumSet.noneOf(HashSupport.class);
    }

    @Override
    protected Hash get(HashParameters params, EnumSet<HashSupport> required) {
        if (isCrc32C(params) && Sse42Crc32C.isSupported())
            return getCacheable(params, required);
        throw new UnsupportedOperationException();
    }

    private static boolean isCrc32C(HashParameters params) {
        return params.equals(CrcParameters.CRC32C);
    }

    @Override
    protected StatelessHash createCacheable(HashParameters params, EnumSet<HashSupport> required) {
        return new Sse42Crc32C(DEFAULT_CHUNK);
    }
}