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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/rand_core/src/block.rs
parent686f61b75055ecb02baf9d9449525ae447a3bed1 (diff)
downloadnitrocli-ecf3474223ca3d16a10f12dc2272e3b0ed72c1bb.tar.gz
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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/rand_core/src/block.rs')
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diff --git a/rand/rand_core/src/block.rs b/rand/rand_core/src/block.rs
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+// 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.
+
+//! The `BlockRngCore` trait and implementation helpers
+//!
+//! The [`BlockRngCore`] trait exists to assist in the implementation of RNGs
+//! which generate a block of data in a cache instead of returning generated
+//! values directly.
+//!
+//! Usage of this trait is optional, but provides two advantages:
+//! implementations only need to concern themselves with generation of the
+//! block, not the various [`RngCore`] methods (especially [`fill_bytes`], where
+//! the optimal implementations are not trivial), and this allows
+//! [`ReseedingRng`] perform periodic reseeding with very low overhead.
+//!
+//! # Example
+//!
+//! ```norun
+//! use rand_core::block::{BlockRngCore, BlockRng};
+//!
+//! struct MyRngCore;
+//!
+//! impl BlockRngCore for MyRngCore {
+//! type Results = [u32; 16];
+//!
+//! fn generate(&mut self, results: &mut Self::Results) {
+//! unimplemented!()
+//! }
+//! }
+//!
+//! impl SeedableRng for MyRngCore {
+//! type Seed = unimplemented!();
+//! fn from_seed(seed: Self::Seed) -> Self {
+//! unimplemented!()
+//! }
+//! }
+//!
+//! // optionally, also implement CryptoRng for MyRngCore
+//!
+//! // Final RNG.
+//! type MyRng = BlockRng<u32, MyRngCore>;
+//! ```
+//!
+//! [`BlockRngCore`]: trait.BlockRngCore.html
+//! [`RngCore`]: ../trait.RngCore.html
+//! [`fill_bytes`]: ../trait.RngCore.html#tymethod.fill_bytes
+//! [`ReseedingRng`]: ../../rand/rngs/adapter/struct.ReseedingRng.html
+
+use core::convert::AsRef;
+use core::fmt;
+use {RngCore, CryptoRng, SeedableRng, Error};
+use impls::{fill_via_u32_chunks, fill_via_u64_chunks};
+
+/// A trait for RNGs which do not generate random numbers individually, but in
+/// blocks (typically `[u32; N]`). This technique is commonly used by
+/// cryptographic RNGs to improve performance.
+///
+/// See the [module documentation](index.html) for details.
+pub trait BlockRngCore {
+ /// Results element type, e.g. `u32`.
+ type Item;
+
+ /// Results type. This is the 'block' an RNG implementing `BlockRngCore`
+ /// generates, which will usually be an array like `[u32; 16]`.
+ type Results: AsRef<[Self::Item]> + AsMut<[Self::Item]> + Default;
+
+ /// Generate a new block of results.
+ fn generate(&mut self, results: &mut Self::Results);
+}
+
+
+/// A wrapper type implementing [`RngCore`] for some type implementing
+/// [`BlockRngCore`] with `u32` array buffer; i.e. this can be used to implement
+/// a full RNG from just a `generate` function.
+///
+/// The `core` field may be accessed directly but the results buffer may not.
+/// PRNG implementations can simply use a type alias
+/// (`pub type MyRng = BlockRng<MyRngCore>;`) but might prefer to use a
+/// wrapper type (`pub struct MyRng(BlockRng<MyRngCore>);`); the latter must
+/// re-implement `RngCore` but hides the implementation details and allows
+/// extra functionality to be defined on the RNG
+/// (e.g. `impl MyRng { fn set_stream(...){...} }`).
+///
+/// `BlockRng` has heavily optimized implementations of the [`RngCore`] methods
+/// reading values from the results buffer, as well as
+/// calling [`BlockRngCore::generate`] directly on the output array when
+/// [`fill_bytes`] / [`try_fill_bytes`] is called on a large array. These methods
+/// also handle the bookkeeping of when to generate a new batch of values.
+///
+/// No whole generated `u32` values are thown away and all values are consumed
+/// in-order. [`next_u32`] simply takes the next available `u32` value.
+/// [`next_u64`] is implemented by combining two `u32` values, least
+/// significant first. [`fill_bytes`] and [`try_fill_bytes`] consume a whole
+/// number of `u32` values, converting each `u32` to a byte slice in
+/// little-endian order. If the requested byte length is not a multiple of 4,
+/// some bytes will be discarded.
+///
+/// See also [`BlockRng64`] which uses `u64` array buffers. Currently there is
+/// no direct support for other buffer types.
+///
+/// For easy initialization `BlockRng` also implements [`SeedableRng`].
+///
+/// [`BlockRngCore`]: BlockRngCore.t.html
+/// [`BlockRngCore::generate`]: trait.BlockRngCore.html#tymethod.generate
+/// [`BlockRng64`]: struct.BlockRng64.html
+/// [`RngCore`]: ../RngCore.t.html
+/// [`next_u32`]: ../trait.RngCore.html#tymethod.next_u32
+/// [`next_u64`]: ../trait.RngCore.html#tymethod.next_u64
+/// [`fill_bytes`]: ../trait.RngCore.html#tymethod.fill_bytes
+/// [`try_fill_bytes`]: ../trait.RngCore.html#tymethod.try_fill_bytes
+/// [`SeedableRng`]: ../SeedableRng.t.html
+#[derive(Clone)]
+#[cfg_attr(feature="serde1", derive(Serialize, Deserialize))]
+pub struct BlockRng<R: BlockRngCore + ?Sized> {
+ results: R::Results,
+ index: usize,
+ /// The *core* part of the RNG, implementing the `generate` function.
+ pub core: R,
+}
+
+// Custom Debug implementation that does not expose the contents of `results`.
+impl<R: BlockRngCore + fmt::Debug> fmt::Debug for BlockRng<R> {
+ fn fmt(&self, fmt: &mut fmt::Formatter) -> fmt::Result {
+ fmt.debug_struct("BlockRng")
+ .field("core", &self.core)
+ .field("result_len", &self.results.as_ref().len())
+ .field("index", &self.index)
+ .finish()
+ }
+}
+
+impl<R: BlockRngCore> BlockRng<R> {
+ /// Create a new `BlockRng` from an existing RNG implementing
+ /// `BlockRngCore`. Results will be generated on first use.
+ pub fn new(core: R) -> BlockRng<R>{
+ let results_empty = R::Results::default();
+ BlockRng {
+ core,
+ index: results_empty.as_ref().len(),
+ results: results_empty,
+ }
+ }
+
+ /// Get the index into the result buffer.
+ ///
+ /// If this is equal to or larger than the size of the result buffer then
+ /// the buffer is "empty" and `generate()` must be called to produce new
+ /// results.
+ pub fn index(&self) -> usize {
+ self.index
+ }
+
+ /// Reset the number of available results.
+ /// This will force a new set of results to be generated on next use.
+ pub fn reset(&mut self) {
+ self.index = self.results.as_ref().len();
+ }
+
+ /// Generate a new set of results immediately, setting the index to the
+ /// given value.
+ pub fn generate_and_set(&mut self, index: usize) {
+ assert!(index < self.results.as_ref().len());
+ self.core.generate(&mut self.results);
+ self.index = index;
+ }
+}
+
+impl<R: BlockRngCore<Item=u32>> RngCore for BlockRng<R>
+where <R as BlockRngCore>::Results: AsRef<[u32]> + AsMut<[u32]>
+{
+ #[inline(always)]
+ fn next_u32(&mut self) -> u32 {
+ if self.index >= self.results.as_ref().len() {
+ self.generate_and_set(0);
+ }
+
+ let value = self.results.as_ref()[self.index];
+ self.index += 1;
+ value
+ }
+
+ #[inline(always)]
+ fn next_u64(&mut self) -> u64 {
+ let read_u64 = |results: &[u32], index| {
+ if cfg!(any(target_arch = "x86", target_arch = "x86_64")) {
+ // requires little-endian CPU supporting unaligned reads:
+ unsafe { *(&results[index] as *const u32 as *const u64) }
+ } else {
+ let x = u64::from(results[index]);
+ let y = u64::from(results[index + 1]);
+ (y << 32) | x
+ }
+ };
+
+ let len = self.results.as_ref().len();
+
+ let index = self.index;
+ if index < len-1 {
+ self.index += 2;
+ // Read an u64 from the current index
+ read_u64(self.results.as_ref(), index)
+ } else if index >= len {
+ self.generate_and_set(2);
+ read_u64(self.results.as_ref(), 0)
+ } else {
+ let x = u64::from(self.results.as_ref()[len-1]);
+ self.generate_and_set(1);
+ let y = u64::from(self.results.as_ref()[0]);
+ (y << 32) | x
+ }
+ }
+
+ // As an optimization we try to write directly into the output buffer.
+ // This is only enabled for little-endian platforms where unaligned writes
+ // are known to be safe and fast.
+ #[cfg(any(target_arch = "x86", target_arch = "x86_64"))]
+ fn fill_bytes(&mut self, dest: &mut [u8]) {
+ let mut filled = 0;
+
+ // Continue filling from the current set of results
+ if self.index < self.results.as_ref().len() {
+ let (consumed_u32, filled_u8) =
+ fill_via_u32_chunks(&self.results.as_ref()[self.index..],
+ dest);
+
+ self.index += consumed_u32;
+ filled += filled_u8;
+ }
+
+ let len_remainder =
+ (dest.len() - filled) % (self.results.as_ref().len() * 4);
+ let end_direct = dest.len() - len_remainder;
+
+ while filled < end_direct {
+ let dest_u32: &mut R::Results = unsafe {
+ &mut *(dest[filled..].as_mut_ptr() as
+ *mut <R as BlockRngCore>::Results)
+ };
+ self.core.generate(dest_u32);
+ filled += self.results.as_ref().len() * 4;
+ self.index = self.results.as_ref().len();
+ }
+
+ if len_remainder > 0 {
+ self.core.generate(&mut self.results);
+ let (consumed_u32, _) =
+ fill_via_u32_chunks(self.results.as_ref(),
+ &mut dest[filled..]);
+
+ self.index = consumed_u32;
+ }
+ }
+
+ #[cfg(not(any(target_arch = "x86", target_arch = "x86_64")))]
+ fn fill_bytes(&mut self, dest: &mut [u8]) {
+ let mut read_len = 0;
+ while read_len < dest.len() {
+ if self.index >= self.results.as_ref().len() {
+ self.generate_and_set(0);
+ }
+ let (consumed_u32, filled_u8) =
+ fill_via_u32_chunks(&self.results.as_ref()[self.index..],
+ &mut dest[read_len..]);
+
+ self.index += consumed_u32;
+ read_len += filled_u8;
+ }
+ }
+
+ fn try_fill_bytes(&mut self, dest: &mut [u8]) -> Result<(), Error> {
+ self.fill_bytes(dest);
+ Ok(())
+ }
+}
+
+impl<R: BlockRngCore + SeedableRng> SeedableRng for BlockRng<R> {
+ type Seed = R::Seed;
+
+ fn from_seed(seed: Self::Seed) -> Self {
+ Self::new(R::from_seed(seed))
+ }
+
+ fn seed_from_u64(seed: u64) -> Self {
+ Self::new(R::seed_from_u64(seed))
+ }
+
+ fn from_rng<S: RngCore>(rng: S) -> Result<Self, Error> {
+ Ok(Self::new(R::from_rng(rng)?))
+ }
+}
+
+
+
+/// A wrapper type implementing [`RngCore`] for some type implementing
+/// [`BlockRngCore`] with `u64` array buffer; i.e. this can be used to implement
+/// a full RNG from just a `generate` function.
+///
+/// This is similar to [`BlockRng`], but specialized for algorithms that operate
+/// on `u64` values.
+///
+/// No whole generated `u64` values are thrown away and all values are consumed
+/// in-order. [`next_u64`] simply takes the next available `u64` value.
+/// [`next_u32`] is however a bit special: half of a `u64` is consumed, leaving
+/// the other half in the buffer. If the next function called is [`next_u32`]
+/// then the other half is then consumed, however both [`next_u64`] and
+/// [`fill_bytes`] discard the rest of any half-consumed `u64`s when called.
+///
+/// [`fill_bytes`] and [`try_fill_bytes`] consume a whole number of `u64`
+/// values. If the requested length is not a multiple of 8, some bytes will be
+/// discarded.
+///
+/// [`BlockRngCore`]: BlockRngCore.t.html
+/// [`RngCore`]: ../RngCore.t.html
+/// [`next_u32`]: ../trait.RngCore.html#tymethod.next_u32
+/// [`next_u64`]: ../trait.RngCore.html#tymethod.next_u64
+/// [`fill_bytes`]: ../trait.RngCore.html#tymethod.fill_bytes
+/// [`try_fill_bytes`]: ../trait.RngCore.html#tymethod.try_fill_bytes
+/// [`BlockRng`]: struct.BlockRng.html
+#[derive(Clone)]
+#[cfg_attr(feature="serde1", derive(Serialize, Deserialize))]
+pub struct BlockRng64<R: BlockRngCore + ?Sized> {
+ results: R::Results,
+ index: usize,
+ half_used: bool, // true if only half of the previous result is used
+ /// The *core* part of the RNG, implementing the `generate` function.
+ pub core: R,
+}
+
+// Custom Debug implementation that does not expose the contents of `results`.
+impl<R: BlockRngCore + fmt::Debug> fmt::Debug for BlockRng64<R> {
+ fn fmt(&self, fmt: &mut fmt::Formatter) -> fmt::Result {
+ fmt.debug_struct("BlockRng64")
+ .field("core", &self.core)
+ .field("result_len", &self.results.as_ref().len())
+ .field("index", &self.index)
+ .field("half_used", &self.half_used)
+ .finish()
+ }
+}
+
+impl<R: BlockRngCore> BlockRng64<R> {
+ /// Create a new `BlockRng` from an existing RNG implementing
+ /// `BlockRngCore`. Results will be generated on first use.
+ pub fn new(core: R) -> BlockRng64<R>{
+ let results_empty = R::Results::default();
+ BlockRng64 {
+ core,
+ index: results_empty.as_ref().len(),
+ half_used: false,
+ results: results_empty,
+ }
+ }
+
+ /// Get the index into the result buffer.
+ ///
+ /// If this is equal to or larger than the size of the result buffer then
+ /// the buffer is "empty" and `generate()` must be called to produce new
+ /// results.
+ pub fn index(&self) -> usize {
+ self.index
+ }
+
+ /// Reset the number of available results.
+ /// This will force a new set of results to be generated on next use.
+ pub fn reset(&mut self) {
+ self.index = self.results.as_ref().len();
+ self.half_used = false;
+ }
+
+ /// Generate a new set of results immediately, setting the index to the
+ /// given value.
+ pub fn generate_and_set(&mut self, index: usize) {
+ assert!(index < self.results.as_ref().len());
+ self.core.generate(&mut self.results);
+ self.index = index;
+ self.half_used = false;
+ }
+}
+
+impl<R: BlockRngCore<Item=u64>> RngCore for BlockRng64<R>
+where <R as BlockRngCore>::Results: AsRef<[u64]> + AsMut<[u64]>
+{
+ #[inline(always)]
+ fn next_u32(&mut self) -> u32 {
+ let mut index = self.index * 2 - self.half_used as usize;
+ if index >= self.results.as_ref().len() * 2 {
+ self.core.generate(&mut self.results);
+ self.index = 0;
+ // `self.half_used` is by definition `false`
+ self.half_used = false;
+ index = 0;
+ }
+
+ self.half_used = !self.half_used;
+ self.index += self.half_used as usize;
+
+ // Index as if this is a u32 slice.
+ unsafe {
+ let results =
+ &*(self.results.as_ref() as *const [u64] as *const [u32]);
+ if cfg!(target_endian = "little") {
+ *results.get_unchecked(index)
+ } else {
+ *results.get_unchecked(index ^ 1)
+ }
+ }
+ }
+
+ #[inline(always)]
+ fn next_u64(&mut self) -> u64 {
+ if self.index >= self.results.as_ref().len() {
+ self.core.generate(&mut self.results);
+ self.index = 0;
+ }
+
+ let value = self.results.as_ref()[self.index];
+ self.index += 1;
+ self.half_used = false;
+ value
+ }
+
+ // As an optimization we try to write directly into the output buffer.
+ // This is only enabled for little-endian platforms where unaligned writes
+ // are known to be safe and fast.
+ #[cfg(any(target_arch = "x86", target_arch = "x86_64"))]
+ fn fill_bytes(&mut self, dest: &mut [u8]) {
+ let mut filled = 0;
+ self.half_used = false;
+
+ // Continue filling from the current set of results
+ if self.index < self.results.as_ref().len() {
+ let (consumed_u64, filled_u8) =
+ fill_via_u64_chunks(&self.results.as_ref()[self.index..],
+ dest);
+
+ self.index += consumed_u64;
+ filled += filled_u8;
+ }
+
+ let len_remainder =
+ (dest.len() - filled) % (self.results.as_ref().len() * 8);
+ let end_direct = dest.len() - len_remainder;
+
+ while filled < end_direct {
+ let dest_u64: &mut R::Results = unsafe {
+ ::core::mem::transmute(dest[filled..].as_mut_ptr())
+ };
+ self.core.generate(dest_u64);
+ filled += self.results.as_ref().len() * 8;
+ self.index = self.results.as_ref().len();
+ }
+
+ if len_remainder > 0 {
+ self.core.generate(&mut self.results);
+ let (consumed_u64, _) =
+ fill_via_u64_chunks(&mut self.results.as_ref(),
+ &mut dest[filled..]);
+
+ self.index = consumed_u64;
+ }
+ }
+
+ #[cfg(not(any(target_arch = "x86", target_arch = "x86_64")))]
+ fn fill_bytes(&mut self, dest: &mut [u8]) {
+ let mut read_len = 0;
+ self.half_used = false;
+ while read_len < dest.len() {
+ if self.index as usize >= self.results.as_ref().len() {
+ self.core.generate(&mut self.results);
+ self.index = 0;
+ }
+
+ let (consumed_u64, filled_u8) =
+ fill_via_u64_chunks(&self.results.as_ref()[self.index as usize..],
+ &mut dest[read_len..]);
+
+ self.index += consumed_u64;
+ read_len += filled_u8;
+ }
+ }
+
+ fn try_fill_bytes(&mut self, dest: &mut [u8]) -> Result<(), Error> {
+ Ok(self.fill_bytes(dest))
+ }
+}
+
+impl<R: BlockRngCore + SeedableRng> SeedableRng for BlockRng64<R> {
+ type Seed = R::Seed;
+
+ fn from_seed(seed: Self::Seed) -> Self {
+ Self::new(R::from_seed(seed))
+ }
+
+ fn seed_from_u64(seed: u64) -> Self {
+ Self::new(R::seed_from_u64(seed))
+ }
+
+ fn from_rng<S: RngCore>(rng: S) -> Result<Self, Error> {
+ Ok(Self::new(R::from_rng(rng)?))
+ }
+}
+
+impl<R: BlockRngCore + CryptoRng> CryptoRng for BlockRng<R> {}