Initial vendor packages

Signed-off-by: Valentin Popov <valentin@popov.link>

1 files changed, 499 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
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+++ b/vendor/rand_core-0.3.1/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` (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> {}