summaryrefslogtreecommitdiff
path: root/rand/src/seq.rs
diff options
context:
space:
mode:
authorDaniel Mueller <deso@posteo.net>2019-01-02 21:14:10 -0800
committerDaniel Mueller <deso@posteo.net>2019-01-02 21:14:10 -0800
commitecf3474223ca3d16a10f12dc2272e3b0ed72c1bb (patch)
tree03134a683791176b49ef5c92e8d6acd24c3b5a9b /rand/src/seq.rs
parent686f61b75055ecb02baf9d9449525ae447a3bed1 (diff)
downloadnitrocli-ecf3474223ca3d16a10f12dc2272e3b0ed72c1bb.tar.gz
nitrocli-ecf3474223ca3d16a10f12dc2272e3b0ed72c1bb.tar.bz2
Update nitrokey crate to 0.2.3
This change updates the nitrokey crate to version 0.2.3. This version bumps the rand crate used to 0.6.1, which in turn requires an additional set of dependencies. Import subrepo nitrokey/:nitrokey at b3e2adc5bb1300441ca74cc7672617c042f3ea31 Import subrepo rand/:rand at 73613ff903512e9503e41cc8ba9eae76269dc598 Import subrepo rustc_version/:rustc_version at 0294f2ba2018bf7be672abd53db351ce5055fa02 Import subrepo semver-parser/:semver-parser at 750da9b11a04125231b1fb293866ca036845acee Import subrepo semver/:semver at 5eb6db94fa03f4d5c64a625a56188f496be47598
Diffstat (limited to 'rand/src/seq.rs')
-rw-r--r--rand/src/seq.rs337
1 files changed, 0 insertions, 337 deletions
diff --git a/rand/src/seq.rs b/rand/src/seq.rs
deleted file mode 100644
index a7889fe..0000000
--- a/rand/src/seq.rs
+++ /dev/null
@@ -1,337 +0,0 @@
-// Copyright 2017 The Rust Project Developers. See the COPYRIGHT
-// file at the top-level directory of this distribution and at
-// http://rust-lang.org/COPYRIGHT.
-//
-// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
-// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
-// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
-// option. This file may not be copied, modified, or distributed
-// except according to those terms.
-
-//! Functions for randomly accessing and sampling sequences.
-
-use super::Rng;
-
-// This crate is only enabled when either std or alloc is available.
-// BTreeMap is not as fast in tests, but better than nothing.
-#[cfg(feature="std")] use std::collections::HashMap;
-#[cfg(not(feature="std"))] use alloc::btree_map::BTreeMap;
-
-#[cfg(not(feature="std"))] use alloc::Vec;
-
-/// Randomly sample `amount` elements from a finite iterator.
-///
-/// The following can be returned:
-/// - `Ok`: `Vec` of `amount` non-repeating randomly sampled elements. The order is not random.
-/// - `Err`: `Vec` of all the elements from `iterable` in sequential order. This happens when the
-/// length of `iterable` was less than `amount`. This is considered an error since exactly
-/// `amount` elements is typically expected.
-///
-/// This implementation uses `O(len(iterable))` time and `O(amount)` memory.
-///
-/// # Example
-///
-/// ```rust
-/// use rand::{thread_rng, seq};
-///
-/// let mut rng = thread_rng();
-/// let sample = seq::sample_iter(&mut rng, 1..100, 5).unwrap();
-/// println!("{:?}", sample);
-/// ```
-pub fn sample_iter<T, I, R>(rng: &mut R, iterable: I, amount: usize) -> Result<Vec<T>, Vec<T>>
- where I: IntoIterator<Item=T>,
- R: Rng,
-{
- let mut iter = iterable.into_iter();
- let mut reservoir = Vec::with_capacity(amount);
- reservoir.extend(iter.by_ref().take(amount));
-
- // Continue unless the iterator was exhausted
- //
- // note: this prevents iterators that "restart" from causing problems.
- // If the iterator stops once, then so do we.
- if reservoir.len() == amount {
- for (i, elem) in iter.enumerate() {
- let k = rng.gen_range(0, i + 1 + amount);
- if let Some(spot) = reservoir.get_mut(k) {
- *spot = elem;
- }
- }
- Ok(reservoir)
- } else {
- // Don't hang onto extra memory. There is a corner case where
- // `amount` was much less than `len(iterable)`.
- reservoir.shrink_to_fit();
- Err(reservoir)
- }
-}
-
-/// Randomly sample exactly `amount` values from `slice`.
-///
-/// The values are non-repeating and in random order.
-///
-/// This implementation uses `O(amount)` time and memory.
-///
-/// Panics if `amount > slice.len()`
-///
-/// # Example
-///
-/// ```rust
-/// use rand::{thread_rng, seq};
-///
-/// let mut rng = thread_rng();
-/// let values = vec![5, 6, 1, 3, 4, 6, 7];
-/// println!("{:?}", seq::sample_slice(&mut rng, &values, 3));
-/// ```
-pub fn sample_slice<R, T>(rng: &mut R, slice: &[T], amount: usize) -> Vec<T>
- where R: Rng,
- T: Clone
-{
- let indices = sample_indices(rng, slice.len(), amount);
-
- let mut out = Vec::with_capacity(amount);
- out.extend(indices.iter().map(|i| slice[*i].clone()));
- out
-}
-
-/// Randomly sample exactly `amount` references from `slice`.
-///
-/// The references are non-repeating and in random order.
-///
-/// This implementation uses `O(amount)` time and memory.
-///
-/// Panics if `amount > slice.len()`
-///
-/// # Example
-///
-/// ```rust
-/// use rand::{thread_rng, seq};
-///
-/// let mut rng = thread_rng();
-/// let values = vec![5, 6, 1, 3, 4, 6, 7];
-/// println!("{:?}", seq::sample_slice_ref(&mut rng, &values, 3));
-/// ```
-pub fn sample_slice_ref<'a, R, T>(rng: &mut R, slice: &'a [T], amount: usize) -> Vec<&'a T>
- where R: Rng
-{
- let indices = sample_indices(rng, slice.len(), amount);
-
- let mut out = Vec::with_capacity(amount);
- out.extend(indices.iter().map(|i| &slice[*i]));
- out
-}
-
-/// Randomly sample exactly `amount` indices from `0..length`.
-///
-/// The values are non-repeating and in random order.
-///
-/// This implementation uses `O(amount)` time and memory.
-///
-/// This method is used internally by the slice sampling methods, but it can sometimes be useful to
-/// have the indices themselves so this is provided as an alternative.
-///
-/// Panics if `amount > length`
-pub fn sample_indices<R>(rng: &mut R, length: usize, amount: usize) -> Vec<usize>
- where R: Rng,
-{
- if amount > length {
- panic!("`amount` must be less than or equal to `slice.len()`");
- }
-
- // We are going to have to allocate at least `amount` for the output no matter what. However,
- // if we use the `cached` version we will have to allocate `amount` as a HashMap as well since
- // it inserts an element for every loop.
- //
- // Therefore, if `amount >= length / 2` then inplace will be both faster and use less memory.
- // In fact, benchmarks show the inplace version is faster for length up to about 20 times
- // faster than amount.
- //
- // TODO: there is probably even more fine-tuning that can be done here since
- // `HashMap::with_capacity(amount)` probably allocates more than `amount` in practice,
- // and a trade off could probably be made between memory/cpu, since hashmap operations
- // are slower than array index swapping.
- if amount >= length / 20 {
- sample_indices_inplace(rng, length, amount)
- } else {
- sample_indices_cache(rng, length, amount)
- }
-}
-
-/// Sample an amount of indices using an inplace partial fisher yates method.
-///
-/// This allocates the entire `length` of indices and randomizes only the first `amount`.
-/// It then truncates to `amount` and returns.
-///
-/// This is better than using a HashMap "cache" when `amount >= length / 2` since it does not
-/// require allocating an extra cache and is much faster.
-fn sample_indices_inplace<R>(rng: &mut R, length: usize, amount: usize) -> Vec<usize>
- where R: Rng,
-{
- debug_assert!(amount <= length);
- let mut indices: Vec<usize> = Vec::with_capacity(length);
- indices.extend(0..length);
- for i in 0..amount {
- let j: usize = rng.gen_range(i, length);
- let tmp = indices[i];
- indices[i] = indices[j];
- indices[j] = tmp;
- }
- indices.truncate(amount);
- debug_assert_eq!(indices.len(), amount);
- indices
-}
-
-
-/// This method performs a partial fisher-yates on a range of indices using a HashMap
-/// as a cache to record potential collisions.
-///
-/// The cache avoids allocating the entire `length` of values. This is especially useful when
-/// `amount <<< length`, i.e. select 3 non-repeating from 1_000_000
-fn sample_indices_cache<R>(
- rng: &mut R,
- length: usize,
- amount: usize,
-) -> Vec<usize>
- where R: Rng,
-{
- debug_assert!(amount <= length);
- #[cfg(feature="std")] let mut cache = HashMap::with_capacity(amount);
- #[cfg(not(feature="std"))] let mut cache = BTreeMap::new();
- let mut out = Vec::with_capacity(amount);
- for i in 0..amount {
- let j: usize = rng.gen_range(i, length);
-
- // equiv: let tmp = slice[i];
- let tmp = match cache.get(&i) {
- Some(e) => *e,
- None => i,
- };
-
- // equiv: slice[i] = slice[j];
- let x = match cache.get(&j) {
- Some(x) => *x,
- None => j,
- };
-
- // equiv: slice[j] = tmp;
- cache.insert(j, tmp);
-
- // note that in the inplace version, slice[i] is automatically "returned" value
- out.push(x);
- }
- debug_assert_eq!(out.len(), amount);
- out
-}
-
-#[cfg(test)]
-mod test {
- use super::*;
- use {thread_rng, XorShiftRng, SeedableRng};
-
- #[test]
- fn test_sample_iter() {
- let min_val = 1;
- let max_val = 100;
-
- let mut r = thread_rng();
- let vals = (min_val..max_val).collect::<Vec<i32>>();
- let small_sample = sample_iter(&mut r, vals.iter(), 5).unwrap();
- let large_sample = sample_iter(&mut r, vals.iter(), vals.len() + 5).unwrap_err();
-
- assert_eq!(small_sample.len(), 5);
- assert_eq!(large_sample.len(), vals.len());
- // no randomization happens when amount >= len
- assert_eq!(large_sample, vals.iter().collect::<Vec<_>>());
-
- assert!(small_sample.iter().all(|e| {
- **e >= min_val && **e <= max_val
- }));
- }
- #[test]
- fn test_sample_slice_boundaries() {
- let empty: &[u8] = &[];
-
- let mut r = thread_rng();
-
- // sample 0 items
- assert_eq!(sample_slice(&mut r, empty, 0), vec![]);
- assert_eq!(sample_slice(&mut r, &[42, 2, 42], 0), vec![]);
-
- // sample 1 item
- assert_eq!(sample_slice(&mut r, &[42], 1), vec![42]);
- let v = sample_slice(&mut r, &[1, 42], 1)[0];
- assert!(v == 1 || v == 42);
-
- // sample "all" the items
- let v = sample_slice(&mut r, &[42, 133], 2);
- assert!(v == vec![42, 133] || v == vec![133, 42]);
-
- assert_eq!(sample_indices_inplace(&mut r, 0, 0), vec![]);
- assert_eq!(sample_indices_inplace(&mut r, 1, 0), vec![]);
- assert_eq!(sample_indices_inplace(&mut r, 1, 1), vec![0]);
-
- assert_eq!(sample_indices_cache(&mut r, 0, 0), vec![]);
- assert_eq!(sample_indices_cache(&mut r, 1, 0), vec![]);
- assert_eq!(sample_indices_cache(&mut r, 1, 1), vec![0]);
-
- // Make sure lucky 777's aren't lucky
- let slice = &[42, 777];
- let mut num_42 = 0;
- let total = 1000;
- for _ in 0..total {
- let v = sample_slice(&mut r, slice, 1);
- assert_eq!(v.len(), 1);
- let v = v[0];
- assert!(v == 42 || v == 777);
- if v == 42 {
- num_42 += 1;
- }
- }
- let ratio_42 = num_42 as f64 / 1000 as f64;
- assert!(0.4 <= ratio_42 || ratio_42 <= 0.6, "{}", ratio_42);
- }
-
- #[test]
- fn test_sample_slice() {
- let xor_rng = XorShiftRng::from_seed;
-
- let max_range = 100;
- let mut r = thread_rng();
-
- for length in 1usize..max_range {
- let amount = r.gen_range(0, length);
- let seed: [u32; 4] = [
- r.next_u32(), r.next_u32(), r.next_u32(), r.next_u32()
- ];
-
- println!("Selecting indices: len={}, amount={}, seed={:?}", length, amount, seed);
-
- // assert that the two index methods give exactly the same result
- let inplace = sample_indices_inplace(
- &mut xor_rng(seed), length, amount);
- let cache = sample_indices_cache(
- &mut xor_rng(seed), length, amount);
- assert_eq!(inplace, cache);
-
- // assert the basics work
- let regular = sample_indices(
- &mut xor_rng(seed), length, amount);
- assert_eq!(regular.len(), amount);
- assert!(regular.iter().all(|e| *e < length));
- assert_eq!(regular, inplace);
-
- // also test that sampling the slice works
- let vec: Vec<usize> = (0..length).collect();
- {
- let result = sample_slice(&mut xor_rng(seed), &vec, amount);
- assert_eq!(result, regular);
- }
-
- {
- let result = sample_slice_ref(&mut xor_rng(seed), &vec, amount);
- let expected = regular.iter().map(|v| v).collect::<Vec<_>>();
- assert_eq!(result, expected);
- }
- }
- }
-}