Crate xoroshiro256_full 

xoroshiro256** PRNG (fast, non-cryptographic)

A tiny, fast implementation of xoroshiro256 without bit waste, intended for simulations, games, and other deterministic workloads. This generator is not cryptographically secure. If you need CSPRNG, enable the "crypto" feature and use CryptoRng256 (ChaCha20).

Features

• rand_core — implements rand_core::RngCore and SeedableRng.
• serde — enables Serialize/Deserialize for Xoroshiro256State.
• crypto — provides CryptoRng256 (ChaCha20) for cryptographic use.

Examples

Fast deterministic numbers (no features required)

use xoroshiro256_full::Xoroshiro256State;

let mut rng = Xoroshiro256State::init([1, 2, 3, 4], 4);
let x = rng.next_u64(); // fast, deterministic

Integrate with rand ecosystem (enable rand_core)

use rand_core::{RngCore, SeedableRng};
use xoroshiro256_full::Xoroshiro256State;

let mut rng = Xoroshiro256State::seed_from_u64(42);
let _ = rng.next_u32();

Cryptographically secure RNG (enable crypto)

use xoroshiro256_full::CryptoRng256;

let mut crng = CryptoRng256::from_os();
let x = crng.next_u64();

Notes

• This crate uses wrapping arithmetic to match the original reference.
• Endianness: byte conversions use little-endian (to_le_bytes).

No bit waste (implementation detail)

When the rand_core feature is enabled, this implementation avoids bit waste in two places:

• next_u32() caches the unused 32 bits from a generated u64 and returns them on the next call.
• fill_bytes() caches any unused tail bytes (up to 7) from a generated u64 and uses them at the start of the next call.

These caches are not part of the algorithmic state and are skipped during serde serialization; only the 256-bit xoroshiro state is serialized.

Structs

CryptoRng256

Cryptographically secure RNG wrapper (ChaCha20).

Xoroshiro256State

Internal state for xoroshiro256** (4 × 64-bit words).