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/*
 * Copyright (C) 2013 Jason Taylor.
 * Released as open-source under the Apache License, Version 2.0.
 *
 * ============================================================================
 * | Joise
 * ============================================================================
 *
 * Copyright (C) 2013 Jason Taylor
 *
 * 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.
 *
 * ============================================================================
 * | Accidental Noise Library
 * | --------------------------------------------------------------------------
 * | Joise is a derivative work based on Josua Tippetts' C++ library:
 * | http://accidentalnoise.sourceforge.net/index.html
 * ============================================================================
 *
 * Copyright (C) 2011 Joshua Tippetts
 *
 *   This software is provided 'as-is', without any express or implied
 *   warranty.  In no event will the authors be held liable for any damages
 *   arising from the use of this software.
 *
 *   Permission is granted to anyone to use this software for any purpose,
 *   including commercial applications, and to alter it and redistribute it
 *   freely, subject to the following restrictions:
 *
 *   1. The origin of this software must not be misrepresented; you must not
 *      claim that you wrote the original software. If you use this software
 *      in a product, an acknowledgment in the product documentation would be
 *      appreciated but is not required.
 *   2. Altered source versions must be plainly marked as such, and must not be
 *      misrepresented as being the original software.
 *   3. This notice may not be removed or altered from any source distribution.
 */
package com.sudoplay.joise.generator

/**
 * Complimentary multiply with carry.
 */
@Suppress("MagicNumber")
open class CMWC4096 : BasePRNG() {

    var c = 0
    var q = IntArray(4096)
    var lcg = LCG()
    var i = 0

    init {
        setSeed(INIT_SEED)
    }

    override fun get(): Int {
        var t: Long
        val a = 18782L
        val b = 4294967295L
        val r = (b - 1).toInt()
        i = i + 1 and 4095
        t = a * q[i] + c
        c = (t shr INT_BITS).toInt()
        t = (t and b) + c
        if (t > r) {
            c++
            t -= b
        }
        q[i] = (r - t).toInt()
        return q[i]
    }

    override fun setSeed(seed: Long) {
        lcg.setSeed(seed)
        for (i in 0..4095) {
            q[i] = lcg.get()
        }
        c = lcg.getTarget(18781)
    }

    companion object {
        private const val INIT_SEED = 10000L
        private const val INT_BITS = 32
    }

}