summaryrefslogtreecommitdiff
path: root/rand/rand_isaac/src/isaac64.rs
diff options
context:
space:
mode:
Diffstat (limited to 'rand/rand_isaac/src/isaac64.rs')
-rw-r--r--rand/rand_isaac/src/isaac64.rs466
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());
- }
- }
-}
generated by cgit v1.2.3 (git 2.46.0) at 2024-11-26 12:54:16 +0000