// Copyright 2018 Developers of the Rand project.
//
// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
// https://www.apache.org/licenses/LICENSE-2.0> or the MIT license
// <LICENSE-MIT or https://opensource.org/licenses/MIT>, at your
// option. This file may not be copied, modified, or distributed
// except according to those terms.

#![feature(test)]
#![allow(non_snake_case)]

extern crate test;

const RAND_BENCH_N: u64 = 1000;
const BYTES_LEN: usize = 1024;

use std::mem::size_of;
use test::{black_box, Bencher};

use rand::prelude::*;
use rand::rngs::adapter::ReseedingRng;
use rand::rngs::{OsRng, mock::StepRng};
use rand_isaac::{IsaacRng, Isaac64Rng};
use rand_chacha::{ChaCha20Core, ChaCha8Rng, ChaCha12Rng, ChaCha20Rng};
use rand_hc::{Hc128Rng};
use rand_pcg::{Pcg32, Pcg64, Pcg64Mcg};
use rand_xorshift::XorShiftRng;
use rand_xoshiro::{Xoshiro256StarStar, Xoshiro256Plus, Xoshiro128StarStar,
    Xoshiro128Plus, Xoroshiro128StarStar, Xoroshiro128Plus, SplitMix64,
    Xoroshiro64StarStar, Xoroshiro64Star};

macro_rules! gen_bytes {
    ($fnn:ident, $gen:expr) => {
        #[bench]
        fn $fnn(b: &mut Bencher) {
            let mut rng = $gen;
            let mut buf = [0u8; BYTES_LEN];
            b.iter(|| {
                for _ in 0..RAND_BENCH_N {
                    rng.fill_bytes(&mut buf);
                    black_box(buf);
                }
            });
            b.bytes = BYTES_LEN as u64 * RAND_BENCH_N;
        }
    }
}

gen_bytes!(gen_bytes_step, StepRng::new(0, 1));
gen_bytes!(gen_bytes_xorshift, XorShiftRng::from_entropy());
gen_bytes!(gen_bytes_xoshiro256starstar, Xoshiro256StarStar::from_entropy());
gen_bytes!(gen_bytes_xoshiro256plus, Xoshiro256Plus::from_entropy());
gen_bytes!(gen_bytes_xoshiro128starstar, Xoshiro128StarStar::from_entropy());
gen_bytes!(gen_bytes_xoshiro128plus, Xoshiro128Plus::from_entropy());
gen_bytes!(gen_bytes_xoroshiro128starstar, Xoroshiro128StarStar::from_entropy());
gen_bytes!(gen_bytes_xoroshiro128plus, Xoroshiro128Plus::from_entropy());
gen_bytes!(gen_bytes_xoroshiro64starstar, Xoroshiro64StarStar::from_entropy());
gen_bytes!(gen_bytes_xoroshiro64star, Xoroshiro64Star::from_entropy());
gen_bytes!(gen_bytes_splitmix64, SplitMix64::from_entropy());
gen_bytes!(gen_bytes_pcg32, Pcg32::from_entropy());
gen_bytes!(gen_bytes_pcg64, Pcg64::from_entropy());
gen_bytes!(gen_bytes_pcg64mcg, Pcg64Mcg::from_entropy());
gen_bytes!(gen_bytes_chacha8, ChaCha8Rng::from_entropy());
gen_bytes!(gen_bytes_chacha12, ChaCha12Rng::from_entropy());
gen_bytes!(gen_bytes_chacha20, ChaCha20Rng::from_entropy());
gen_bytes!(gen_bytes_hc128, Hc128Rng::from_entropy());
gen_bytes!(gen_bytes_isaac, IsaacRng::from_entropy());
gen_bytes!(gen_bytes_isaac64, Isaac64Rng::from_entropy());
gen_bytes!(gen_bytes_std, StdRng::from_entropy());
#[cfg(feature="small_rng")]
gen_bytes!(gen_bytes_small, SmallRng::from_entropy());
gen_bytes!(gen_bytes_os, OsRng);

macro_rules! gen_uint {
    ($fnn:ident, $ty:ty, $gen:expr) => {
        #[bench]
        fn $fnn(b: &mut Bencher) {
            let mut rng = $gen;
            b.iter(|| {
                let mut accum: $ty = 0;
                for _ in 0..RAND_BENCH_N {
                    accum = accum.wrapping_add(rng.gen::<$ty>());
                }
                accum
            });
            b.bytes = size_of::<$ty>() as u64 * RAND_BENCH_N;
        }
    }
}

gen_uint!(gen_u32_step, u32, StepRng::new(0, 1));
gen_uint!(gen_u32_xorshift, u32, XorShiftRng::from_entropy());
gen_uint!(gen_u32_xoshiro256starstar, u32, Xoshiro256StarStar::from_entropy());
gen_uint!(gen_u32_xoshiro256plus, u32, Xoshiro256Plus::from_entropy());
gen_uint!(gen_u32_xoshiro128starstar, u32, Xoshiro128StarStar::from_entropy());
gen_uint!(gen_u32_xoshiro128plus, u32, Xoshiro128Plus::from_entropy());
gen_uint!(gen_u32_xoroshiro128starstar, u32, Xoroshiro128StarStar::from_entropy());
gen_uint!(gen_u32_xoroshiro128plus, u32, Xoroshiro128Plus::from_entropy());
gen_uint!(gen_u32_xoroshiro64starstar, u32, Xoroshiro64StarStar::from_entropy());
gen_uint!(gen_u32_xoroshiro64star, u32, Xoroshiro64Star::from_entropy());
gen_uint!(gen_u32_splitmix64, u32, SplitMix64::from_entropy());
gen_uint!(gen_u32_pcg32, u32, Pcg32::from_entropy());
gen_uint!(gen_u32_pcg64, u32, Pcg64::from_entropy());
gen_uint!(gen_u32_pcg64mcg, u32, Pcg64Mcg::from_entropy());
gen_uint!(gen_u32_chacha8, u32, ChaCha8Rng::from_entropy());
gen_uint!(gen_u32_chacha12, u32, ChaCha12Rng::from_entropy());
gen_uint!(gen_u32_chacha20, u32, ChaCha20Rng::from_entropy());
gen_uint!(gen_u32_hc128, u32, Hc128Rng::from_entropy());
gen_uint!(gen_u32_isaac, u32, IsaacRng::from_entropy());
gen_uint!(gen_u32_isaac64, u32, Isaac64Rng::from_entropy());
gen_uint!(gen_u32_std, u32, StdRng::from_entropy());
#[cfg(feature="small_rng")]
gen_uint!(gen_u32_small, u32, SmallRng::from_entropy());
gen_uint!(gen_u32_os, u32, OsRng);

gen_uint!(gen_u64_step, u64, StepRng::new(0, 1));
gen_uint!(gen_u64_xorshift, u64, XorShiftRng::from_entropy());
gen_uint!(gen_u64_xoshiro256starstar, u64, Xoshiro256StarStar::from_entropy());
gen_uint!(gen_u64_xoshiro256plus, u64, Xoshiro256Plus::from_entropy());
gen_uint!(gen_u64_xoshiro128starstar, u64, Xoshiro128StarStar::from_entropy());
gen_uint!(gen_u64_xoshiro128plus, u64, Xoshiro128Plus::from_entropy());
gen_uint!(gen_u64_xoroshiro128starstar, u64, Xoroshiro128StarStar::from_entropy());
gen_uint!(gen_u64_xoroshiro128plus, u64, Xoroshiro128Plus::from_entropy());
gen_uint!(gen_u64_xoroshiro64starstar, u64, Xoroshiro64StarStar::from_entropy());
gen_uint!(gen_u64_xoroshiro64star, u64, Xoroshiro64Star::from_entropy());
gen_uint!(gen_u64_splitmix64, u64, SplitMix64::from_entropy());
gen_uint!(gen_u64_pcg32, u64, Pcg32::from_entropy());
gen_uint!(gen_u64_pcg64, u64, Pcg64::from_entropy());
gen_uint!(gen_u64_pcg64mcg, u64, Pcg64Mcg::from_entropy());
gen_uint!(gen_u64_chacha8, u64, ChaCha8Rng::from_entropy());
gen_uint!(gen_u64_chacha12, u64, ChaCha12Rng::from_entropy());
gen_uint!(gen_u64_chacha20, u64, ChaCha20Rng::from_entropy());
gen_uint!(gen_u64_hc128, u64, Hc128Rng::from_entropy());
gen_uint!(gen_u64_isaac, u64, IsaacRng::from_entropy());
gen_uint!(gen_u64_isaac64, u64, Isaac64Rng::from_entropy());
gen_uint!(gen_u64_std, u64, StdRng::from_entropy());
#[cfg(feature="small_rng")]
gen_uint!(gen_u64_small, u64, SmallRng::from_entropy());
gen_uint!(gen_u64_os, u64, OsRng);

macro_rules! init_gen {
    ($fnn:ident, $gen:ident) => {
        #[bench]
        fn $fnn(b: &mut Bencher) {
            let mut rng = XorShiftRng::from_entropy();
            b.iter(|| {
                let r2 = $gen::from_rng(&mut rng).unwrap();
                r2
            });
        }
    }
}

init_gen!(init_xorshift, XorShiftRng);
init_gen!(init_xoshiro256starstar, Xoshiro256StarStar);
init_gen!(init_xoshiro256plus, Xoshiro256Plus);
init_gen!(init_xoshiro128starstar, Xoshiro128StarStar);
init_gen!(init_xoshiro128plus, Xoshiro128Plus);
init_gen!(init_xoroshiro128starstar, Xoroshiro128StarStar);
init_gen!(init_xoroshiro128plus, Xoroshiro128Plus);
init_gen!(init_xoroshiro64starstar, Xoroshiro64StarStar);
init_gen!(init_xoroshiro64star, Xoroshiro64Star);
init_gen!(init_splitmix64, SplitMix64);
init_gen!(init_pcg32, Pcg32);
init_gen!(init_pcg64, Pcg64);
init_gen!(init_pcg64mcg, Pcg64Mcg);
init_gen!(init_hc128, Hc128Rng);
init_gen!(init_isaac, IsaacRng);
init_gen!(init_isaac64, Isaac64Rng);
init_gen!(init_chacha, ChaCha20Rng);

const RESEEDING_BYTES_LEN: usize = 1024 * 1024;
const RESEEDING_BENCH_N: u64 = 16;

macro_rules! reseeding_bytes {
    ($fnn:ident, $thresh:expr) => {
        #[bench]
        fn $fnn(b: &mut Bencher) {
            let mut rng = ReseedingRng::new(ChaCha20Core::from_entropy(),
                                            $thresh * 1024,
                                            OsRng);
            let mut buf = [0u8; RESEEDING_BYTES_LEN];
            b.iter(|| {
                for _ in 0..RESEEDING_BENCH_N {
                    rng.fill_bytes(&mut buf);
                    black_box(&buf);
                }
            });
            b.bytes = RESEEDING_BYTES_LEN as u64 * RESEEDING_BENCH_N;
        }
    }
}

reseeding_bytes!(reseeding_chacha20_4k, 4);
reseeding_bytes!(reseeding_chacha20_16k, 16);
reseeding_bytes!(reseeding_chacha20_32k, 32);
reseeding_bytes!(reseeding_chacha20_64k, 64);
reseeding_bytes!(reseeding_chacha20_256k, 256);
reseeding_bytes!(reseeding_chacha20_1M, 1024);


macro_rules! threadrng_uint {
    ($fnn:ident, $ty:ty) => {
        #[bench]
        fn $fnn(b: &mut Bencher) {
            let mut rng = thread_rng();
            b.iter(|| {
                let mut accum: $ty = 0;
                for _ in 0..RAND_BENCH_N {
                    accum = accum.wrapping_add(rng.gen::<$ty>());
                }
                accum
            });
            b.bytes = size_of::<$ty>() as u64 * RAND_BENCH_N;
        }
    }
}

threadrng_uint!(thread_rng_u32, u32);
threadrng_uint!(thread_rng_u64, u64);