/*
 * 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.
 */

/*
 * This is not the original file distributed by the Apache Software Foundation
 * It has been modified by the Hipparchus project
 */
package org.hipparchus.random;


/**
 * Interface for generators of random number sequences.
 */
public interface RandomGenerator {

    /**
     * Sets the seed of the underlying random number generator using an
     * <code>int</code> seed.
     * <p>
     * Sequences of values generated starting with the same seeds
     * should be identical.
     *
     * @param seed the seed value
     */
    void setSeed(int seed);

    /**
     * Sets the seed of the underlying random number generator using an
     * <code>int</code> array seed.
     * <p>
     * Sequences of values generated starting with the same seeds
     * should be identical.
     *
     * @param seed the seed value
     */
    void setSeed(int[] seed);

    /**
     * Sets the seed of the underlying random number generator using a
     * <code>long</code> seed.
     * <p>
     * Sequences of values generated starting with the same seeds
     * should be identical.
     *
     * @param seed the seed value
     */
    void setSeed(long seed);

    /**
     * Generates random bytes and places them into a user-supplied
     * byte array. The number of random bytes produced is equal to
     * the length of the byte array.
     *
     * @param bytes the non-null byte array in which to put the random bytes
     */
    void nextBytes(byte[] bytes);

    /**
     * Generates random bytes and places them into a user-supplied
     * byte array.
     *
     * @param bytes the non-null byte array in which to put the random bytes
     * @param offset the starting index for inserting the generated bytes into
     * the array
     * @param len the number of bytes to generate
     * @throws org.hipparchus.exception.MathIllegalArgumentException if {@code offset < 0} or
     * {@code offset + len >= bytes.length}
     */
    void nextBytes(byte[] bytes, int offset, int len);

    /**
     * Returns the next pseudorandom, uniformly distributed {@code int}
     * value from this random number generator's sequence.
     * <p>
     * All 2<sup>32</sup> possible {@code int} values should be produced
     * with (approximately) equal probability.
     *
     * @return the next pseudorandom, uniformly distributed {@code int}
     * value from this random number generator's sequence
     */
    int nextInt();

    /**
     * Returns a pseudorandom, uniformly distributed {@code int} value
     * between 0 (inclusive) and the specified value (exclusive), drawn from
     * this random number generator's sequence.
     *
     * @param n the bound on the random number to be returned. Must be positive.
     * @return  a pseudorandom, uniformly distributed {@code int}
     * value between 0 (inclusive) and n (exclusive).
     * @throws IllegalArgumentException if n is not positive.
     */
    int nextInt(int n);

    /**
     * Returns the next pseudorandom, uniformly distributed {@code long}
     * value from this random number generator's sequence. All 2<sup>64</sup>
     * possible {@code long} values should be produced with (approximately)
     * equal probability.
     *
     * @return the next pseudorandom, uniformly distributed {@code long}
     * value from this random number generator's sequence
     */
    long nextLong();

    /**
     * Returns a pseudorandom, uniformly distributed {@code int} value
     * between 0 (inclusive) and the specified value (exclusive), drawn from
     * this random number generator's sequence.
     *
     * @param n the bound on the random number to be returned. Must be positive.
     * @return  a pseudorandom, uniformly distributed {@code int}
     * value between 0 (inclusive) and n (exclusive).
     * @throws IllegalArgumentException if n is not positive.
     */
    long nextLong(long n);

    /**
     * Returns the next pseudorandom, uniformly distributed
     * {@code boolean} value from this random number generator's sequence.
     *
     * @return  the next pseudorandom, uniformly distributed
     * <code>boolean</code> value from this random number generator's
     * sequence
     */
    boolean nextBoolean();

    /**
     * Returns the next pseudorandom, uniformly distributed {@code float}
     * value between <code>0.0</code> and <code>1.0</code> from this random
     * number generator's sequence.
     *
     * @return  the next pseudorandom, uniformly distributed {@code float}
     * value between <code>0.0</code> and <code>1.0</code> from this
     * random number generator's sequence
     */
    float nextFloat();

    /**
     * Returns the next pseudorandom, uniformly distributed
     * <code>double</code> value between <code>0.0</code> and
     * <code>1.0</code> from this random number generator's sequence.
     *
     * @return  the next pseudorandom, uniformly distributed
     *  <code>double</code> value between <code>0.0</code> and
     *  <code>1.0</code> from this random number generator's sequence
     */
    double nextDouble();

    /**
     * Returns the next pseudorandom, Gaussian ("normally") distributed
     * <code>double</code> value with mean <code>0.0</code> and standard
     * deviation <code>1.0</code> from this random number generator's sequence.
     *
     * @return  the next pseudorandom, Gaussian ("normally") distributed
     * <code>double</code> value with mean <code>0.0</code> and
     * standard deviation <code>1.0</code> from this random number
     *  generator's sequence
     */
    double nextGaussian();
}
