Struct soroban_sdk::prng::Prng

pub struct Prng { /* private fields */ }

Prng is a pseudo-random generator.

Warning

The PRNG is unsuitable for generating secrets or use in applications with low risk tolerance, see the module-level comment.

Implementations

impl Prng

pub fn env(&self) -> &Env

pub fn seed(&self, seed: Bytes)

Reseeds the PRNG with the provided value.

The seed is combined with the seed assigned to the contract invocation.

Warning

The PRNG is unsuitable for generating secrets or use in applications with low risk tolerance, see the module-level comment.

pub fn u64_in_range(&self, r: impl RangeBounds<u64>) -> u64

Returns a random u64 in the range specified.

Panics

If the range is empty.

Warning

The PRNG is unsuitable for generating secrets or use in applications with low risk tolerance, see the module-level comment.

Examples

use soroban_sdk::{Env};

// Get values in the range of 1 to 100, inclusive.
let value = env.prng().u64_in_range(1..=100);
assert_eq!(value, 77);
let value = env.prng().u64_in_range(1..=100);
assert_eq!(value, 66);
let value = env.prng().u64_in_range(1..=100);
assert_eq!(value, 72);

pub fn shuffle<V>(&self, v: V) -> Vec<Val>where V: IntoVal<Env, Vec<Val>>,

Shuffles a given vector v using the Fisher-Yates algorithm.

Warning

The PRNG is unsuitable for generating secrets or use in applications with low risk tolerance, see the module-level comment.