Here's my delimna: I am writing an application that needs to exactly reproduce the PRNG output from a game that was written in Java that uses the Java random() with a given seed to create all it's initial game 'world' data.
The problem I am facing is that Java's random() and ios Swift native PRNG do not generate the same values when given the exact same seeds.
Here are my test cases: In all cases the same 'seed' is used, and the formula is for a random Integer between 0 and 9.
In Java:
import java.util.Random;
long seed = 987234904;
Random rnd = new Random(seed);
int result = rnd.nextInt(10);
The Java random() 'result' = 0
Swift - using srand48() / drand48():
import UIKit
var seed: Int = 987234904
srand48(seed)
var result = Int(drand48()*10)
The ios Swift drand48() 'result' = 7
In Swift - using rand_r():
import UIKit
var seed: UInt32 = 987234904
var result = Int(Float(rand_r(&seed))/Float(INT32_MAX)*10)
The ios Swift rand_r() result = 4
In Swift - using the new GKLinearCongruentialRandomSource - which uses a simular Linear Congruential method that Java.util.random() was based on - suposedly:
import UIKit
import GameplayKit
if #available (iOS 9,*) {
let seed: UInt64 = 987234904
let random = GKLinearCongruentialRandomSource(seed: seed)
let result = random.nextIntWithUpperBound(10) // should be a random Int from 0 to 9 (total 10 possibilities }
result = 6
With that in mind - is there a ios Swift|Objective-C|C++ code snippit|library available that is the exact same in functionality and output as the Java's version of random()?