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Diffstat (limited to 'rand/rand_isaac/src/isaac64.rs')
| -rw-r--r-- | rand/rand_isaac/src/isaac64.rs | 466 |
1 files changed, 0 insertions, 466 deletions
diff --git a/rand/rand_isaac/src/isaac64.rs b/rand/rand_isaac/src/isaac64.rs deleted file mode 100644 index 7d4b88c..0000000 --- a/rand/rand_isaac/src/isaac64.rs +++ /dev/null @@ -1,466 +0,0 @@ -// Copyright 2018 Developers of the Rand project. -// Copyright 2013-2018 The Rust Project Developers. -// -// 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. - -//! The ISAAC-64 random number generator. - -use core::{fmt, slice}; -use core::num::Wrapping as w; -#[cfg(feature="serde1")] use serde::{Serialize, Deserialize}; -use rand_core::{RngCore, SeedableRng, Error, le}; -use rand_core::block::{BlockRngCore, BlockRng64}; -use crate::isaac_array::IsaacArray; - -#[allow(non_camel_case_types)] -type w64 = w<u64>; - -const RAND_SIZE_LEN: usize = 8; -const RAND_SIZE: usize = 1 << RAND_SIZE_LEN; - -/// A random number generator that uses ISAAC-64, the 64-bit variant of the -/// ISAAC algorithm. -/// -/// ISAAC stands for "Indirection, Shift, Accumulate, Add, and Count" which are -/// the principal bitwise operations employed. It is the most advanced of a -/// series of array based random number generator designed by Robert Jenkins -/// in 1996[^1]. -/// -/// ISAAC-64 is mostly similar to ISAAC. Because it operates on 64-bit integers -/// instead of 32-bit, it uses twice as much memory to hold its state and -/// results. Also it uses different constants for shifts and indirect indexing, -/// optimized to give good results for 64bit arithmetic. -/// -/// ISAAC-64 is notably fast and produces excellent quality random numbers for -/// non-cryptographic applications. -/// -/// In spite of being designed with cryptographic security in mind, ISAAC hasn't -/// been stringently cryptanalyzed and thus cryptographers do not not -/// consensually trust it to be secure. When looking for a secure RNG, prefer -/// `Hc128Rng` from the [`rand_hc`] crate instead, which, like ISAAC, is an -/// array-based RNG and one of the stream-ciphers selected the by eSTREAM -/// -/// ## Overview of the ISAAC-64 algorithm: -/// (in pseudo-code) -/// -/// ```text -/// Input: a, b, c, s[256] // state -/// Output: r[256] // results -/// -/// mix(a,i) = !(a ^ a << 21) if i = 0 mod 4 -/// a ^ a >> 5 if i = 1 mod 4 -/// a ^ a << 12 if i = 2 mod 4 -/// a ^ a >> 33 if i = 3 mod 4 -/// -/// c = c + 1 -/// b = b + c -/// -/// for i in 0..256 { -/// x = s_[i] -/// a = mix(a,i) + s[i+128 mod 256] -/// y = a + b + s[x>>3 mod 256] -/// s[i] = y -/// b = x + s[y>>11 mod 256] -/// r[i] = b -/// } -/// ``` -/// -/// This implementation uses [`BlockRng64`] to implement the [`RngCore`] methods. -/// -/// See for more information the documentation of [`IsaacRng`]. -/// -/// [^1]: Bob Jenkins, [*ISAAC and RC4*]( -/// http://burtleburtle.net/bob/rand/isaac.html) -/// -/// [`IsaacRng`]: crate::isaac::IsaacRng -/// [`rand_hc`]: https://docs.rs/rand_hc -/// [`BlockRng64`]: rand_core::block::BlockRng64 -#[derive(Clone, Debug)] -#[cfg_attr(feature="serde1", derive(Serialize, Deserialize))] -pub struct Isaac64Rng(BlockRng64<Isaac64Core>); - -impl RngCore for Isaac64Rng { - #[inline] - fn next_u32(&mut self) -> u32 { - self.0.next_u32() - } - - #[inline] - fn next_u64(&mut self) -> u64 { - self.0.next_u64() - } - - #[inline] - fn fill_bytes(&mut self, dest: &mut [u8]) { - self.0.fill_bytes(dest) - } - - #[inline] - fn try_fill_bytes(&mut self, dest: &mut [u8]) -> Result<(), Error> { - self.0.try_fill_bytes(dest) - } -} - -impl SeedableRng for Isaac64Rng { - type Seed = <Isaac64Core as SeedableRng>::Seed; - - #[inline] - fn from_seed(seed: Self::Seed) -> Self { - Isaac64Rng(BlockRng64::<Isaac64Core>::from_seed(seed)) - } - - /// Create an ISAAC random number generator using an `u64` as seed. - /// If `seed == 0` this will produce the same stream of random numbers as - /// the reference implementation when used unseeded. - #[inline] - fn seed_from_u64(seed: u64) -> Self { - Isaac64Rng(BlockRng64::<Isaac64Core>::seed_from_u64(seed)) - } - - #[inline] - fn from_rng<S: RngCore>(rng: S) -> Result<Self, Error> { - BlockRng64::<Isaac64Core>::from_rng(rng).map(|rng| Isaac64Rng(rng)) - } -} - -/// The core of `Isaac64Rng`, used with `BlockRng`. -#[derive(Clone)] -#[cfg_attr(feature="serde1", derive(Serialize, Deserialize))] -pub struct Isaac64Core { - #[cfg_attr(feature="serde1",serde(with="super::isaac_array::isaac_array_serde"))] - mem: [w64; RAND_SIZE], - a: w64, - b: w64, - c: w64, -} - -// Custom Debug implementation that does not expose the internal state -impl fmt::Debug for Isaac64Core { - fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result { - write!(f, "Isaac64Core {{}}") - } -} - -impl BlockRngCore for Isaac64Core { - type Item = u64; - type Results = IsaacArray<Self::Item>; - - /// Refills the output buffer, `results`. See also the pseudocode desciption - /// of the algorithm in the `Isaac64Rng` documentation. - /// - /// Optimisations used (similar to the reference implementation): - /// - /// - The loop is unrolled 4 times, once for every constant of mix(). - /// - The contents of the main loop are moved to a function `rngstep`, to - /// reduce code duplication. - /// - We use local variables for a and b, which helps with optimisations. - /// - We split the main loop in two, one that operates over 0..128 and one - /// over 128..256. This way we can optimise out the addition and modulus - /// from `s[i+128 mod 256]`. - /// - We maintain one index `i` and add `m` or `m2` as base (m2 for the - /// `s[i+128 mod 256]`), relying on the optimizer to turn it into pointer - /// arithmetic. - /// - We fill `results` backwards. The reference implementation reads values - /// from `results` in reverse. We read them in the normal direction, to - /// make `fill_bytes` a memcopy. To maintain compatibility we fill in - /// reverse. - fn generate(&mut self, results: &mut IsaacArray<Self::Item>) { - self.c += w(1); - // abbreviations - let mut a = self.a; - let mut b = self.b + self.c; - const MIDPOINT: usize = RAND_SIZE / 2; - - #[inline] - fn ind(mem:&[w64; RAND_SIZE], v: w64, amount: usize) -> w64 { - let index = (v >> amount).0 as usize % RAND_SIZE; - mem[index] - } - - #[inline] - fn rngstep(mem: &mut [w64; RAND_SIZE], - results: &mut [u64; RAND_SIZE], - mix: w64, - a: &mut w64, - b: &mut w64, - base: usize, - m: usize, - m2: usize) { - let x = mem[base + m]; - *a = mix + mem[base + m2]; - let y = *a + *b + ind(&mem, x, 3); - mem[base + m] = y; - *b = x + ind(&mem, y, 3 + RAND_SIZE_LEN); - results[RAND_SIZE - 1 - base - m] = (*b).0; - } - - let mut m = 0; - let mut m2 = MIDPOINT; - for i in (0..MIDPOINT/4).map(|i| i * 4) { - rngstep(&mut self.mem, results, !(a ^ (a << 21)), &mut a, &mut b, i + 0, m, m2); - rngstep(&mut self.mem, results, a ^ (a >> 5 ), &mut a, &mut b, i + 1, m, m2); - rngstep(&mut self.mem, results, a ^ (a << 12), &mut a, &mut b, i + 2, m, m2); - rngstep(&mut self.mem, results, a ^ (a >> 33), &mut a, &mut b, i + 3, m, m2); - } - - m = MIDPOINT; - m2 = 0; - for i in (0..MIDPOINT/4).map(|i| i * 4) { - rngstep(&mut self.mem, results, !(a ^ (a << 21)), &mut a, &mut b, i + 0, m, m2); - rngstep(&mut self.mem, results, a ^ (a >> 5 ), &mut a, &mut b, i + 1, m, m2); - rngstep(&mut self.mem, results, a ^ (a << 12), &mut a, &mut b, i + 2, m, m2); - rngstep(&mut self.mem, results, a ^ (a >> 33), &mut a, &mut b, i + 3, m, m2); - } - - self.a = a; - self.b = b; - } -} - -impl Isaac64Core { - /// Create a new ISAAC-64 random number generator. - fn init(mut mem: [w64; RAND_SIZE], rounds: u32) -> Self { - fn mix(a: &mut w64, b: &mut w64, c: &mut w64, d: &mut w64, - e: &mut w64, f: &mut w64, g: &mut w64, h: &mut w64) { - *a -= *e; *f ^= *h >> 9; *h += *a; - *b -= *f; *g ^= *a << 9; *a += *b; - *c -= *g; *h ^= *b >> 23; *b += *c; - *d -= *h; *a ^= *c << 15; *c += *d; - *e -= *a; *b ^= *d >> 14; *d += *e; - *f -= *b; *c ^= *e << 20; *e += *f; - *g -= *c; *d ^= *f >> 17; *f += *g; - *h -= *d; *e ^= *g << 14; *g += *h; - } - - // These numbers are the result of initializing a...h with the - // fractional part of the golden ratio in binary (0x9e3779b97f4a7c13) - // and applying mix() 4 times. - let mut a = w(0x647c4677a2884b7c); - let mut b = w(0xb9f8b322c73ac862); - let mut c = w(0x8c0ea5053d4712a0); - let mut d = w(0xb29b2e824a595524); - let mut e = w(0x82f053db8355e0ce); - let mut f = w(0x48fe4a0fa5a09315); - let mut g = w(0xae985bf2cbfc89ed); - let mut h = w(0x98f5704f6c44c0ab); - - // Normally this should do two passes, to make all of the seed effect - // all of `mem` - for _ in 0..rounds { - for i in (0..RAND_SIZE/8).map(|i| i * 8) { - a += mem[i ]; b += mem[i+1]; - c += mem[i+2]; d += mem[i+3]; - e += mem[i+4]; f += mem[i+5]; - g += mem[i+6]; h += mem[i+7]; - mix(&mut a, &mut b, &mut c, &mut d, - &mut e, &mut f, &mut g, &mut h); - mem[i ] = a; mem[i+1] = b; - mem[i+2] = c; mem[i+3] = d; - mem[i+4] = e; mem[i+5] = f; - mem[i+6] = g; mem[i+7] = h; - } - } - - Self { mem, a: w(0), b: w(0), c: w(0) } - } -} - -impl SeedableRng for Isaac64Core { - type Seed = [u8; 32]; - - fn from_seed(seed: Self::Seed) -> Self { - let mut seed_u64 = [0u64; 4]; - le::read_u64_into(&seed, &mut seed_u64); - // Convert the seed to `Wrapping<u64>` and zero-extend to `RAND_SIZE`. - let mut seed_extended = [w(0); RAND_SIZE]; - for (x, y) in seed_extended.iter_mut().zip(seed_u64.iter()) { - *x = w(*y); - } - Self::init(seed_extended, 2) - } - - fn seed_from_u64(seed: u64) -> Self { - let mut key = [w(0); RAND_SIZE]; - key[0] = w(seed); - // Initialize with only one pass. - // A second pass does not improve the quality here, because all of the - // seed was already available in the first round. - // Not doing the second pass has the small advantage that if - // `seed == 0` this method produces exactly the same state as the - // reference implementation when used unseeded. - Self::init(key, 1) - } - - fn from_rng<R: RngCore>(mut rng: R) -> Result<Self, Error> { - // Custom `from_rng` implementation that fills a seed with the same size - // as the entire state. - let mut seed = [w(0u64); RAND_SIZE]; - unsafe { - let ptr = seed.as_mut_ptr() as *mut u8; - let slice = slice::from_raw_parts_mut(ptr, RAND_SIZE * 8); - rng.try_fill_bytes(slice)?; - } - for i in seed.iter_mut() { - *i = w(i.0.to_le()); - } - - Ok(Self::init(seed, 2)) - } -} - -#[cfg(test)] -mod test { - use rand_core::{RngCore, SeedableRng}; - use super::Isaac64Rng; - - #[test] - fn test_isaac64_construction() { - // Test that various construction techniques produce a working RNG. - let seed = [1,0,0,0, 23,0,0,0, 200,1,0,0, 210,30,0,0, - 0,0,0,0, 0,0,0,0, 0,0,0,0, 0,0,0,0]; - let mut rng1 = Isaac64Rng::from_seed(seed); - assert_eq!(rng1.next_u64(), 14964555543728284049); - - let mut rng2 = Isaac64Rng::from_rng(rng1).unwrap(); - assert_eq!(rng2.next_u64(), 919595328260451758); - } - - #[test] - fn test_isaac64_true_values_64() { - let seed = [1,0,0,0, 0,0,0,0, 23,0,0,0, 0,0,0,0, - 200,1,0,0, 0,0,0,0, 210,30,0,0, 0,0,0,0]; - let mut rng1 = Isaac64Rng::from_seed(seed); - let mut results = [0u64; 10]; - for i in results.iter_mut() { *i = rng1.next_u64(); } - let expected = [ - 15071495833797886820, 7720185633435529318, - 10836773366498097981, 5414053799617603544, - 12890513357046278984, 17001051845652595546, - 9240803642279356310, 12558996012687158051, - 14673053937227185542, 1677046725350116783]; - assert_eq!(results, expected); - - let seed = [57,48,0,0, 0,0,0,0, 50,9,1,0, 0,0,0,0, - 49,212,0,0, 0,0,0,0, 148,38,0,0, 0,0,0,0]; - let mut rng2 = Isaac64Rng::from_seed(seed); - // skip forward to the 10000th number - for _ in 0..10000 { rng2.next_u64(); } - - for i in results.iter_mut() { *i = rng2.next_u64(); } - let expected = [ - 18143823860592706164, 8491801882678285927, 2699425367717515619, - 17196852593171130876, 2606123525235546165, 15790932315217671084, - 596345674630742204, 9947027391921273664, 11788097613744130851, - 10391409374914919106]; - assert_eq!(results, expected); - } - - #[test] - fn test_isaac64_true_values_32() { - let seed = [1,0,0,0, 0,0,0,0, 23,0,0,0, 0,0,0,0, - 200,1,0,0, 0,0,0,0, 210,30,0,0, 0,0,0,0]; - let mut rng = Isaac64Rng::from_seed(seed); - let mut results = [0u32; 12]; - for i in results.iter_mut() { *i = rng.next_u32(); } - // Subset of above values, as an LE u32 sequence - let expected = [ - 3477963620, 3509106075, - 687845478, 1797495790, - 227048253, 2523132918, - 4044335064, 1260557630, - 4079741768, 3001306521, - 69157722, 3958365844]; - assert_eq!(results, expected); - } - - #[test] - fn test_isaac64_true_values_mixed() { - let seed = [1,0,0,0, 0,0,0,0, 23,0,0,0, 0,0,0,0, - 200,1,0,0, 0,0,0,0, 210,30,0,0, 0,0,0,0]; - let mut rng = Isaac64Rng::from_seed(seed); - // Test alternating between `next_u64` and `next_u32` works as expected. - // Values are the same as `test_isaac64_true_values` and - // `test_isaac64_true_values_32`. - assert_eq!(rng.next_u64(), 15071495833797886820); - assert_eq!(rng.next_u32(), 687845478); - assert_eq!(rng.next_u32(), 1797495790); - assert_eq!(rng.next_u64(), 10836773366498097981); - assert_eq!(rng.next_u32(), 4044335064); - // Skip one u32 - assert_eq!(rng.next_u64(), 12890513357046278984); - assert_eq!(rng.next_u32(), 69157722); - } - - #[test] - fn test_isaac64_true_bytes() { - let seed = [1,0,0,0, 0,0,0,0, 23,0,0,0, 0,0,0,0, - 200,1,0,0, 0,0,0,0, 210,30,0,0, 0,0,0,0]; - let mut rng = Isaac64Rng::from_seed(seed); - let mut results = [0u8; 32]; - rng.fill_bytes(&mut results); - // Same as first values in test_isaac64_true_values as bytes in LE order - let expected = [100, 131, 77, 207, 155, 181, 40, 209, - 102, 176, 255, 40, 238, 155, 35, 107, - 61, 123, 136, 13, 246, 243, 99, 150, - 216, 167, 15, 241, 62, 149, 34, 75]; - assert_eq!(results, expected); - } - - #[test] - fn test_isaac64_new_uninitialized() { - // Compare the results from initializing `IsaacRng` with - // `seed_from_u64(0)`, to make sure it is the same as the reference - // implementation when used uninitialized. - // Note: We only test the first 16 integers, not the full 256 of the - // first block. - let mut rng = Isaac64Rng::seed_from_u64(0); - let mut results = [0u64; 16]; - for i in results.iter_mut() { *i = rng.next_u64(); } - let expected: [u64; 16] = [ - 0xF67DFBA498E4937C, 0x84A5066A9204F380, 0xFEE34BD5F5514DBB, - 0x4D1664739B8F80D6, 0x8607459AB52A14AA, 0x0E78BC5A98529E49, - 0xFE5332822AD13777, 0x556C27525E33D01A, 0x08643CA615F3149F, - 0xD0771FAF3CB04714, 0x30E86F68A37B008D, 0x3074EBC0488A3ADF, - 0x270645EA7A2790BC, 0x5601A0A8D3763C6A, 0x2F83071F53F325DD, - 0xB9090F3D42D2D2EA]; - assert_eq!(results, expected); - } - - #[test] - fn test_isaac64_clone() { - let seed = [1,0,0,0, 0,0,0,0, 23,0,0,0, 0,0,0,0, - 200,1,0,0, 0,0,0,0, 210,30,0,0, 0,0,0,0]; - let mut rng1 = Isaac64Rng::from_seed(seed); - let mut rng2 = rng1.clone(); - for _ in 0..16 { - assert_eq!(rng1.next_u64(), rng2.next_u64()); - } - } - - #[test] - #[cfg(feature="serde1")] - fn test_isaac64_serde() { - use bincode; - use std::io::{BufWriter, BufReader}; - - let seed = [1,0,0,0, 23,0,0,0, 200,1,0,0, 210,30,0,0, - 57,48,0,0, 0,0,0,0, 0,0,0,0, 0,0,0,0]; - let mut rng = Isaac64Rng::from_seed(seed); - - let buf: Vec<u8> = Vec::new(); - let mut buf = BufWriter::new(buf); - bincode::serialize_into(&mut buf, &rng).expect("Could not serialize"); - - let buf = buf.into_inner().unwrap(); - let mut read = BufReader::new(&buf[..]); - let mut deserialized: Isaac64Rng = bincode::deserialize_from(&mut read).expect("Could not deserialize"); - - for _ in 0..300 { // more than the 256 buffered results - assert_eq!(rng.next_u64(), deserialized.next_u64()); - } - } -} |