Source of randomness in kotlin-stdlib-common

Question

In kotlin-stdlib-common is there any source of randomness available out of the box? Whether it's some implementation of standard java.util.Random, kotlin.math.random* or basic current time millis that I can use to create my own random number generator? I can't find any.

If it's not there, how would you get the source of randomness without setting your own platform dependent implementations? This is the only method I need:

expect class Rng {
    fun nextInt(): Int
}

I'm trying to make it platform agnostic.

Answer 1

The answer would be: wait for Kotlin 1.3 to get released where the common library will be enriched with classes and methods that can provide the source for random values.

https://kotlinlang.org/docs/reference/whatsnew13.html#multiplatform-random

Answer 2

This maybe a post with many links, which may cause the problem of Your answer is in another castle: when is an answer not an answer?, so I try my best to write the link description. And my understanding of Kotlin Multiplatform is Kotlin-Multiplatform = Kotlin-JVM + Kotlin-JS.

I believe that the random number of Kotlin-JVM is provided by java.util.Random, and Math.Random() if it is Kotlin-JS, with these following reasons:

• How can I get a random number in Kotlin?, and there is an answer in that question said that Kotlin-JS can use Math.Random() to get random number.
• Can't get any result of any random number related method of Kotlin-JVM, but there is a random() in Kotlin-JS.
• The source code of Kotlin-JVM related file, while using Random(), there is a import java.util.*, or some file directly use java.util.Random for example kotlin/libraries/stdlib/jvm/src/kotlin/collections/MutableCollectionsJVM.kt#L78.

And, java.util.Random is designed as result platform-independent, and also implementation platform-independent, with these reason:

• Is Java's RNG (using seeds) platform-independent?, though this question may be out-dated.
• We can't find keyword "native" in the source of JDK8/java.util.Random or the source of JDK10/java.util.Random, and the RNG logic is clear in these source code, where seed is decided by nanoTime() if not provided, and RNG is the implementation of Volume 2, TAOCP.

So, I think,

How would you get the source of randomness without setting your own platform dependent implementations?

Maybe a random-enough seed and a random-enough (P)RNG.