hadoop-hdfs-project/hadoop-hdfs/src/contrib/libhdfs3/src/common/HWCrc32c.h

/**
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you 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.
 */

#ifndef _HDFS_LIBHDFS3_COMMON_HWCHECKSUM_H_
#define _HDFS_LIBHDFS3_COMMON_HWCHECKSUM_H_

#include "Checksum.h"

namespace hdfs {
namespace internal {

/**
 * Calculate CRC with hardware support.
 */
class HWCrc32c: public Checksum {
public:
    /**
     * Constructor.
     */
    HWCrc32c() :
        crc(0xFFFFFFFF) {
    }

    uint32_t getValue() {
        return ~crc;
    }

    /**
     * @ref Checksum#reset()
     */
    void reset() {
        crc = 0xFFFFFFFF;
    }

    /**
     * @ref Checksum#update(const void *, int)
     */
    void update(const void *b, int len);

    /**
     * Destory an HWCrc32 instance.
     */
    ~HWCrc32c() {
    }

    /**
     * To test if the hardware support this function.
     * @return true if the hardware support to calculate the CRC.
     */
    static bool available();

private:
    void updateInt64(const char *b, int len);

private:
    uint32_t crc;
};

}
}

#endif /* _HDFS_LIBHDFS3_COMMON_HWCHECKSUM_H_ */