diff options
Diffstat (limited to 'vendor/rand_core-0.3.1/src')
| -rw-r--r-- | vendor/rand_core-0.3.1/src/block.rs | 499 | ||||
| -rw-r--r-- | vendor/rand_core-0.3.1/src/error.rs | 177 | ||||
| -rw-r--r-- | vendor/rand_core-0.3.1/src/impls.rs | 165 | ||||
| -rw-r--r-- | vendor/rand_core-0.3.1/src/le.rs | 68 | ||||
| -rw-r--r-- | vendor/rand_core-0.3.1/src/lib.rs | 46 |
5 files changed, 955 insertions, 0 deletions
diff --git a/vendor/rand_core-0.3.1/src/block.rs b/vendor/rand_core-0.3.1/src/block.rs new file mode 100644 index 0000000..3045b94 --- /dev/null +++ b/vendor/rand_core-0.3.1/src/block.rs @@ -0,0 +1,499 @@ +// 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` (see [`rand`](https://docs.rs/rand) crate) 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`]: crate::block::BlockRngCore +//! [`fill_bytes`]: RngCore::fill_bytes + +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][crate::block] documentation 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`]. +/// +/// [`next_u32`]: RngCore::next_u32 +/// [`next_u64`]: RngCore::next_u64 +/// [`fill_bytes`]: RngCore::fill_bytes +/// [`try_fill_bytes`]: RngCore::try_fill_bytes +#[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. +/// +/// [`next_u32`]: RngCore::next_u32 +/// [`next_u64`]: RngCore::next_u64 +/// [`fill_bytes`]: RngCore::fill_bytes +/// [`try_fill_bytes`]: RngCore::try_fill_bytes +#[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> {} diff --git a/vendor/rand_core-0.3.1/src/error.rs b/vendor/rand_core-0.3.1/src/error.rs new file mode 100644 index 0000000..5a8459e --- /dev/null +++ b/vendor/rand_core-0.3.1/src/error.rs @@ -0,0 +1,177 @@ +// 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. + +//! Error types + +use core::fmt; + +#[cfg(feature="std")] +use std::error::Error as stdError; +#[cfg(feature="std")] +use std::io; + +/// Error kind which can be matched over. +#[derive(PartialEq, Eq, Debug, Copy, Clone)] +pub enum ErrorKind { + /// Feature is not available; not recoverable. + /// + /// This is the most permanent failure type and implies the error cannot be + /// resolved simply by retrying (e.g. the feature may not exist in this + /// build of the application or on the current platform). + Unavailable, + /// General failure; there may be a chance of recovery on retry. + /// + /// This is the catch-all kind for errors from known and unknown sources + /// which do not have a more specific kind / handling method. + /// + /// It is suggested to retry a couple of times or retry later when + /// handling; some error sources may be able to resolve themselves, + /// although this is not likely. + Unexpected, + /// A transient failure which likely can be resolved or worked around. + /// + /// This error kind exists for a few specific cases where it is known that + /// the error likely can be resolved internally, but is reported anyway. + Transient, + /// Not ready yet: recommended to try again a little later. + /// + /// This error kind implies the generator needs more time or needs some + /// other part of the application to do something else first before it is + /// ready for use; for example this may be used by external generators + /// which require time for initialization. + NotReady, + #[doc(hidden)] + __Nonexhaustive, +} + +impl ErrorKind { + /// True if this kind of error may resolve itself on retry. + /// + /// See also `should_wait()`. + pub fn should_retry(self) -> bool { + self != ErrorKind::Unavailable + } + + /// True if we should retry but wait before retrying + /// + /// This implies `should_retry()` is true. + pub fn should_wait(self) -> bool { + self == ErrorKind::NotReady + } + + /// A description of this error kind + pub fn description(self) -> &'static str { + match self { + ErrorKind::Unavailable => "permanently unavailable", + ErrorKind::Unexpected => "unexpected failure", + ErrorKind::Transient => "transient failure", + ErrorKind::NotReady => "not ready yet", + ErrorKind::__Nonexhaustive => unreachable!(), + } + } +} + + +/// Error type of random number generators +/// +/// This is a relatively simple error type, designed for compatibility with and +/// without the Rust `std` library. It embeds a "kind" code, a message (static +/// string only), and an optional chained cause (`std` only). The `kind` and +/// `msg` fields can be accessed directly; cause can be accessed via +/// `std::error::Error::cause` or `Error::take_cause`. Construction can only be +/// done via `Error::new` or `Error::with_cause`. +#[derive(Debug)] +pub struct Error { + /// The error kind + pub kind: ErrorKind, + /// The error message + pub msg: &'static str, + #[cfg(feature="std")] + cause: Option<Box<stdError + Send + Sync>>, +} + +impl Error { + /// Create a new instance, with specified kind and a message. + pub fn new(kind: ErrorKind, msg: &'static str) -> Self { + #[cfg(feature="std")] { + Error { kind, msg, cause: None } + } + #[cfg(not(feature="std"))] { + Error { kind, msg } + } + } + + /// Create a new instance, with specified kind, message, and a + /// chained cause. + /// + /// Note: `stdError` is an alias for `std::error::Error`. + /// + /// If not targetting `std` (i.e. `no_std`), this function is replaced by + /// another with the same prototype, except that there are no bounds on the + /// type `E` (because both `Box` and `stdError` are unavailable), and the + /// `cause` is ignored. + #[cfg(feature="std")] + pub fn with_cause<E>(kind: ErrorKind, msg: &'static str, cause: E) -> Self + where E: Into<Box<stdError + Send + Sync>> + { + Error { kind, msg, cause: Some(cause.into()) } + } + + /// Create a new instance, with specified kind, message, and a + /// chained cause. + /// + /// In `no_std` mode the *cause* is ignored. + #[cfg(not(feature="std"))] + pub fn with_cause<E>(kind: ErrorKind, msg: &'static str, _cause: E) -> Self { + Error { kind, msg } + } + + /// Take the cause, if any. This allows the embedded cause to be extracted. + /// This uses `Option::take`, leaving `self` with no cause. + #[cfg(feature="std")] + pub fn take_cause(&mut self) -> Option<Box<stdError + Send + Sync>> { + self.cause.take() + } +} + +impl fmt::Display for Error { + fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result { + #[cfg(feature="std")] { + if let Some(ref cause) = self.cause { + return write!(f, "{} ({}); cause: {}", + self.msg, self.kind.description(), cause); + } + } + write!(f, "{} ({})", self.msg, self.kind.description()) + } +} + +#[cfg(feature="std")] +impl stdError for Error { + fn description(&self) -> &str { + self.msg + } + + fn cause(&self) -> Option<&stdError> { + self.cause.as_ref().map(|e| e.as_ref() as &stdError) + } +} + +#[cfg(feature="std")] +impl From<Error> for io::Error { + fn from(error: Error) -> Self { + use std::io::ErrorKind::*; + match error.kind { + ErrorKind::Unavailable => io::Error::new(NotFound, error), + ErrorKind::Unexpected | + ErrorKind::Transient => io::Error::new(Other, error), + ErrorKind::NotReady => io::Error::new(WouldBlock, error), + ErrorKind::__Nonexhaustive => unreachable!(), + } + } +} diff --git a/vendor/rand_core-0.3.1/src/impls.rs b/vendor/rand_core-0.3.1/src/impls.rs new file mode 100644 index 0000000..57bdd07 --- /dev/null +++ b/vendor/rand_core-0.3.1/src/impls.rs @@ -0,0 +1,165 @@ +// 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. + +//! Helper functions for implementing `RngCore` functions. +//! +//! For cross-platform reproducibility, these functions all use Little Endian: +//! least-significant part first. For example, `next_u64_via_u32` takes `u32` +//! values `x, y`, then outputs `(y << 32) | x`. To implement `next_u32` +//! from `next_u64` in little-endian order, one should use `next_u64() as u32`. +//! +//! Byte-swapping (like the std `to_le` functions) is only needed to convert +//! to/from byte sequences, and since its purpose is reproducibility, +//! non-reproducible sources (e.g. `OsRng`) need not bother with it. + +use core::intrinsics::transmute; +use core::ptr::copy_nonoverlapping; +use core::slice; +use core::cmp::min; +use core::mem::size_of; +use RngCore; + + +/// Implement `next_u64` via `next_u32`, little-endian order. +pub fn next_u64_via_u32<R: RngCore + ?Sized>(rng: &mut R) -> u64 { + // Use LE; we explicitly generate one value before the next. + let x = u64::from(rng.next_u32()); + let y = u64::from(rng.next_u32()); + (y << 32) | x +} + +/// Implement `fill_bytes` via `next_u64` and `next_u32`, little-endian order. +/// +/// The fastest way to fill a slice is usually to work as long as possible with +/// integers. That is why this method mostly uses `next_u64`, and only when +/// there are 4 or less bytes remaining at the end of the slice it uses +/// `next_u32` once. +pub fn fill_bytes_via_next<R: RngCore + ?Sized>(rng: &mut R, dest: &mut [u8]) { + let mut left = dest; + while left.len() >= 8 { + let (l, r) = {left}.split_at_mut(8); + left = r; + let chunk: [u8; 8] = unsafe { + transmute(rng.next_u64().to_le()) + }; + l.copy_from_slice(&chunk); + } + let n = left.len(); + if n > 4 { + let chunk: [u8; 8] = unsafe { + transmute(rng.next_u64().to_le()) + }; + left.copy_from_slice(&chunk[..n]); + } else if n > 0 { + let chunk: [u8; 4] = unsafe { + transmute(rng.next_u32().to_le()) + }; + left.copy_from_slice(&chunk[..n]); + } +} + +macro_rules! impl_uint_from_fill { + ($rng:expr, $ty:ty, $N:expr) => ({ + debug_assert!($N == size_of::<$ty>()); + + let mut int: $ty = 0; + unsafe { + let ptr = &mut int as *mut $ty as *mut u8; + let slice = slice::from_raw_parts_mut(ptr, $N); + $rng.fill_bytes(slice); + } + int + }); +} + +macro_rules! fill_via_chunks { + ($src:expr, $dst:expr, $ty:ty, $size:expr) => ({ + let chunk_size_u8 = min($src.len() * $size, $dst.len()); + let chunk_size = (chunk_size_u8 + $size - 1) / $size; + if cfg!(target_endian="little") { + unsafe { + copy_nonoverlapping( + $src.as_ptr() as *const u8, + $dst.as_mut_ptr(), + chunk_size_u8); + } + } else { + for (&n, chunk) in $src.iter().zip($dst.chunks_mut($size)) { + let tmp = n.to_le(); + let src_ptr = &tmp as *const $ty as *const u8; + unsafe { + copy_nonoverlapping(src_ptr, + chunk.as_mut_ptr(), + chunk.len()); + } + } + } + + (chunk_size, chunk_size_u8) + }); +} + +/// Implement `fill_bytes` by reading chunks from the output buffer of a block +/// based RNG. +/// +/// The return values are `(consumed_u32, filled_u8)`. +/// +/// `filled_u8` is the number of filled bytes in `dest`, which may be less than +/// the length of `dest`. +/// `consumed_u32` is the number of words consumed from `src`, which is the same +/// as `filled_u8 / 4` rounded up. +/// +/// # Example +/// (from `IsaacRng`) +/// +/// ```ignore +/// fn fill_bytes(&mut self, dest: &mut [u8]) { +/// let mut read_len = 0; +/// while read_len < dest.len() { +/// if self.index >= self.rsl.len() { +/// self.isaac(); +/// } +/// +/// let (consumed_u32, filled_u8) = +/// impls::fill_via_u32_chunks(&mut self.rsl[self.index..], +/// &mut dest[read_len..]); +/// +/// self.index += consumed_u32; +/// read_len += filled_u8; +/// } +/// } +/// ``` +pub fn fill_via_u32_chunks(src: &[u32], dest: &mut [u8]) -> (usize, usize) { + fill_via_chunks!(src, dest, u32, 4) +} + +/// Implement `fill_bytes` by reading chunks from the output buffer of a block +/// based RNG. +/// +/// The return values are `(consumed_u64, filled_u8)`. +/// `filled_u8` is the number of filled bytes in `dest`, which may be less than +/// the length of `dest`. +/// `consumed_u64` is the number of words consumed from `src`, which is the same +/// as `filled_u8 / 8` rounded up. +/// +/// See `fill_via_u32_chunks` for an example. +pub fn fill_via_u64_chunks(src: &[u64], dest: &mut [u8]) -> (usize, usize) { + fill_via_chunks!(src, dest, u64, 8) +} + +/// Implement `next_u32` via `fill_bytes`, little-endian order. +pub fn next_u32_via_fill<R: RngCore + ?Sized>(rng: &mut R) -> u32 { + impl_uint_from_fill!(rng, u32, 4) +} + +/// Implement `next_u64` via `fill_bytes`, little-endian order. +pub fn next_u64_via_fill<R: RngCore + ?Sized>(rng: &mut R) -> u64 { + impl_uint_from_fill!(rng, u64, 8) +} + +// TODO: implement tests for the above diff --git a/vendor/rand_core-0.3.1/src/le.rs b/vendor/rand_core-0.3.1/src/le.rs new file mode 100644 index 0000000..266651f --- /dev/null +++ b/vendor/rand_core-0.3.1/src/le.rs @@ -0,0 +1,68 @@ +// 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. + +//! Little-Endian utilities +//! +//! Little-Endian order has been chosen for internal usage; this makes some +//! useful functions available. + +use core::ptr; + +macro_rules! read_slice { + ($src:expr, $dst:expr, $size:expr, $which:ident) => {{ + assert_eq!($src.len(), $size * $dst.len()); + + unsafe { + ptr::copy_nonoverlapping( + $src.as_ptr(), + $dst.as_mut_ptr() as *mut u8, + $src.len()); + } + for v in $dst.iter_mut() { + *v = v.$which(); + } + }}; +} + +/// Reads unsigned 32 bit integers from `src` into `dst`. +/// Borrowed from the `byteorder` crate. +#[inline] +pub fn read_u32_into(src: &[u8], dst: &mut [u32]) { + read_slice!(src, dst, 4, to_le); +} + +/// Reads unsigned 64 bit integers from `src` into `dst`. +/// Borrowed from the `byteorder` crate. +#[inline] +pub fn read_u64_into(src: &[u8], dst: &mut [u64]) { + read_slice!(src, dst, 8, to_le); +} + +#[test] +fn test_read() { + let bytes = [1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16]; + + let mut buf = [0u32; 4]; + read_u32_into(&bytes, &mut buf); + assert_eq!(buf[0], 0x04030201); + assert_eq!(buf[3], 0x100F0E0D); + + let mut buf = [0u32; 3]; + read_u32_into(&bytes[1..13], &mut buf); // unaligned + assert_eq!(buf[0], 0x05040302); + assert_eq!(buf[2], 0x0D0C0B0A); + + let mut buf = [0u64; 2]; + read_u64_into(&bytes, &mut buf); + assert_eq!(buf[0], 0x0807060504030201); + assert_eq!(buf[1], 0x100F0E0D0C0B0A09); + + let mut buf = [0u64; 1]; + read_u64_into(&bytes[7..15], &mut buf); // unaligned + assert_eq!(buf[0], 0x0F0E0D0C0B0A0908); +} diff --git a/vendor/rand_core-0.3.1/src/lib.rs b/vendor/rand_core-0.3.1/src/lib.rs new file mode 100644 index 0000000..8923142 --- /dev/null +++ b/vendor/rand_core-0.3.1/src/lib.rs @@ -0,0 +1,46 @@ +// Copyright 2018 Developers of the Rand project. +// Copyright 2017-2018 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. + +//! Random number generation traits +//! +//! This version of `rand_core` is a compatibility shim around version 0.3. +//! +//! This crate is mainly of interest to crates publishing implementations of +//! [`RngCore`]. Other users are encouraged to use the [`rand`] crate instead +//! which re-exports the main traits and error types. +//! +//! [`RngCore`] is the core trait implemented by algorithmic pseudo-random number +//! generators and external random-number sources. +//! +//! [`SeedableRng`] is an extension trait for construction from fixed seeds and +//! other random number generators. +//! +//! [`Error`] is provided for error-handling. It is safe to use in `no_std` +//! environments. +//! +//! The [`impls`] and [`le`] sub-modules include a few small functions to assist +//! implementation of [`RngCore`]. +//! +//! [`rand`]: https://docs.rs/rand + +#![doc(html_logo_url = "https://www.rust-lang.org/logos/rust-logo-128x128-blk.png", + html_favicon_url = "https://www.rust-lang.org/favicon.ico", + html_root_url = "https://rust-random.github.io/rand/")] + +#![deny(missing_docs)] +#![deny(missing_debug_implementations)] +#![doc(test(attr(allow(unused_variables), deny(warnings))))] + +#![no_std] + +extern crate rand_core as core4; + +pub use core4::{ErrorKind, Error}; +pub use core4::{block, impls, le}; +pub use core4::{RngCore, CryptoRng, SeedableRng}; |