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package org.apidesign.api.security;

import java.nio.ByteBuffer;

import org.apidesign.spi.security.Digestor;

/**

 *

 * @author Jaroslav Tulach <jaroslav.tulach@apidesign.org>

 */

final class DigestImplementation<Data> {

    private static final DigestorAccessorImpl ACCESSOR = new DigestorAccessorImpl();

    private final Digestor<Data> digestor;

    private final String algorithm;

    private Data data;

    private DigestImplementation(Digestor<Data> digestor, String algorithm, Data d) {

        this.digestor = digestor;

        this.algorithm = algorithm;

        this.data = d;

    }

    static <Data> DigestImplementation create(Digestor<Data> digestor, String algorithm) {

        Data d = ACCESSOR.create(digestor, algorithm);

        if (d == null) {

            return null;

        } else {

            return new DigestImplementation(digestor, algorithm, d);

        }

    }

    byte[] digest(ByteBuffer bb) {

        ACCESSOR.update(digestor, data, bb);

        return ACCESSOR.digest(digestor, data);

    }

}