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package com.github.czietsman.xxhash;

/*
 * 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.
 */

import java.util.Random;

/**
 * Entry point to get {@link XXHash32} and {@link StreamingXXHash32} instances.
 */
public final class XXHashFactory {

    public static XXHashFactory INSTANCE = new XXHashFactory();
    private final XXHash32 hash32;
    private final XXHash64 hash64;
    private final StreamingXXHash32.Factory streamingHash32Factory;
    private final StreamingXXHash64.Factory streamingHash64Factory;

    private XXHashFactory() {
        hash32 = XXHash32JavaSafe.INSTANCE;
        streamingHash32Factory = new StreamingXXHash32JavaSafe.Factory();
        hash64 = XXHash64JavaSafe.INSTANCE;
        streamingHash64Factory = new StreamingXXHash64JavaSafe.Factory();

        // make sure it can run
        final byte[] bytes = new byte[100];
        final Random random = new Random();
        random.nextBytes(bytes);
        final int seed = random.nextInt();

        final int h1 = hash32.hash(bytes, 0, bytes.length, seed);
        final StreamingXXHash32 streamingHash32 = newStreamingHash32(seed);
        streamingHash32.update(bytes, 0, bytes.length);
        final int h2 = streamingHash32.getValue();
        final long h3 = hash64.hash(bytes, 0, bytes.length, seed);
        final StreamingXXHash64 streamingHash64 = newStreamingHash64(seed);
        streamingHash64.update(bytes, 0, bytes.length);
        final long h4 = streamingHash64.getValue();
        if (h1 != h2) {
            throw new AssertionError();
        }
        if (h3 != h4) {
            throw new AssertionError();
        }
    }

    /**
     * Prints the fastest instance.
     */
    public static void main(String[] args) {
        System.out.println("Fastest instance is " + XXHashFactory.INSTANCE);
    }

    /**
     * Return a {@link XXHash32} instance.
     */
    public XXHash32 hash32() {
        return hash32;
    }

    /**
     * Return a {@link XXHash64} instance.
     */
    public XXHash64 hash64() {
        return hash64;
    }

    /**
     * Return a new {@link StreamingXXHash32} instance.
     */
    public StreamingXXHash32 newStreamingHash32(int seed) {
        return streamingHash32Factory.newStreamingHash(seed);
    }

    /**
     * Return a new {@link StreamingXXHash64} instance.
     */
    public StreamingXXHash64 newStreamingHash64(long seed) {
        return streamingHash64Factory.newStreamingHash(seed);
    }

}