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/**
* *****************************************************************************
*
* Design and Development by msg Applied Technology Research Copyright (c) 2019-2020 msg systems
* ag (http://www.msg-systems.com/) All Rights Reserved.
*
*
Permission is hereby granted, free of charge, to any person obtaining a copy of this software
* and associated documentation files (the "Software"), to deal in the Software without restriction,
* including without limitation the rights to use, copy, modify, merge, publish, distribute,
* sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
*
The above copyright notice and this permission notice shall be included in all copies or
* substantial portions of the Software.
*
*
THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING
* BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
* NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM,
* DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
*
*
****************************************************************************
*/
package com.graphqlio.uuid.helpers;
import java.time.LocalDateTime;
import java.time.ZoneId;
import com.graphqlio.uuid.domain.GlobaleConstants;
/**
* PcgPrng helps to create random Number from Time((PRNG)).
*
* @author Michael Schüfer
* @author Ahmed Amedlous
* @author Dr. Edgar Müller
*/
public final class PcgPrng {
/**
* utility function: simple Pseudo Random Number Generator (PRNG).
*
* @param len length of the result
* @param radix the radix to create the random number
* @param store the store
* @return the array which create with the pseudo random number generator
* @throws Exception may be thrown by createMagicConstant
*/
public static long[] getPrngClock(int len, int radix, long[] store) throws Exception {
long[] bytes = new long[len];
long[] storeStateInner = {-9223372036854775808L, 0, 0, 0, 0, 0, 0, 9223372036854775807L};
for (int i = 0; i < len; i++) {
// zu machen
// bytes[i] = (pcg.next() % radix);
bytes[i] = createMagicConstant(storeStateInner) % radix;
}
// Copy current state into store
for (int i = 0; i < storeStateInner.length; i++) {
store[i] = storeStateInner[i];
}
return bytes;
}
/**
* utility function: simple Pseudo Random Number Generator (PRNG).
*
* @param len length of the result
* @param radix the radix to create the random number
* @param store the store
* @return the array which create with the pseudo random number generator
* @throws Exception may be thrown by createMagicConstant
*/
public static long[] getPrngLocal(int len, int radix, long[] store) throws Exception {
long[] bytes = new long[len];
for (int i = 0; i < len; i++) {
// zu machen
// bytes[i] = (pcg.next() % radix);
bytes[i] = createMagicConstant(store) % radix;
}
return bytes;
}
/**
* clone the UI64.
*
* @param x the UI64 to clone
* @return the cloned UI64
*/
private static long[] getUi64Clone(long[] x) {
// x.slice(0) zu pruffen, but x.slice(0) gibt immer x als Wert
return x;
}
/**
* clone the UI64.
*
* @param x the UI64 to clone
* @param y a UI64
* @return the cloned copy UI64
*/
private static long[] getUi64CloneCopy(long[] x, long[] y) {
// x.slice(0) zu pruffen, but x.slice(0) gibt immer x als Wert
for (int i = 0; i < x.length; i++) {
y[i] = x[i];
}
return y;
}
/**
* PCG Pseudo-Random-Number-Generator (PRNG).
*
*
http://www.pcg-random.org/pdf/hmc-cs-2014-0905.pdf This is the PCG-XSH-RR variant ("xorshift
* high (bits), random rotation"), based on 32-bit output, 64-bit internal state and the formulas:
*
*
var PCG = function (seed).
*
* @param store input
* @return a pseudoNumber
* @throws Exception may be thrown by createMagicConstant
*/
public static long createMagicConstant(long[] store) throws Exception {
/* pre-load some "magic" constants */
long[] mul = UI64Common.getUi64D2i(GlobaleConstants.MUL_TAB);
long[] inc = UI64Common.getUi64D2i(GlobaleConstants.INC_TAB);
// Zu pruffen Art : int oder double !!!!!
/* generate an initial internal state */
long[] state = new long[8];
long[] stateNew = new long[8];
if (store[0] == Long.MIN_VALUE && store[7] == Long.MAX_VALUE) {
// Generate state from current Time
// long n= new Date().getTime();
long n = LocalDateTime.now().atZone(ZoneId.systemDefault()).toInstant().toEpochMilli();
System.out.println("n : " + n);
state = UI64.getUi64N2i(GlobaleConstants.TAB_0, n);
// state = getUi64Clone(inc);// use before ???
/// ***** ---- ******\\\
/* save current state */
getUi64CloneCopy(state, stateNew);
// PCG.prototype.next = function ()
/* advance internal state */
UI64Common.getUi64Mul(state, mul);
UI64Common.getUi64Add_2(state, inc);
} else {
state = getUi64Clone(store);
/// ***** ---- ******\\\
/* save current state */
// stateNew=getUi64Clone(state);
getUi64CloneCopy(state, stateNew);
// PCG.prototype.next = function ()
/* advance internal state */
UI64Common.getUi64Mul(state, mul);
UI64Common.getUi64Add_2(state, inc);
}
// Copy current state into store
for (int i = 0; i < state.length; i++) {
store[i] = state[i];
}
/* calculate: (state ^ (state >> 18)) >> 27 */
long[] outPut = getUi64Clone(stateNew);
/* rotate right UI64 (x) by a "s" bits and return overflow/carry as number */
long[] stateNew64 = new long[8];
for (int i = 0; i < stateNew.length; i++) {
stateNew64[i] = stateNew[i];
}
UI64Common.getUi64Ror(outPut, GlobaleConstants.OUTPUT_18);
UI64Common.getUi64Xor(outPut, stateNew64);
UI64Common.getUi64Ror(outPut, GlobaleConstants.OUTPUT_27);
/* calculate: state >> 59 */
long[] rot = getUi64Clone(stateNew64);
UI64Common.getUi64Ror(rot, GlobaleConstants.OUTPUT_59);
/* calculate: rotate32(xorshifted, rot) */
long[] mask = UI64Common.getUi64D2i(GlobaleConstants.MASK_TAB);
UI64Common.getUi64And(outPut, mask);
long k = UI64Common.getUi64I2n(rot);
// OutPut 2 from OutPut
long[] outPut2 = getUi64Clone(outPut);
long[] outPutK = new long[8];
for (int i = 0; i < outPut.length; i++) {
outPutK[i] = outPut[i];
}
UI64Common.getUi64Rol(outPut2, 32 - k);
UI64Common.getUi64Ror(outPutK, k);
UI64Common.getUi64Xor(outPutK, outPut2);
/* return pseudo-random number */
long pseudoNumber = UI64Common.getUi64I2n(outPutK);
return pseudoNumber;
}
/*
* Copy Table into Table.
*/
public static void CopyTabltInoTable(long[] table1, long[] table2) {
// nothing
}
}