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| <span id="523">523</span> |
| <span id="524">524</span> |
| <span id="525">525</span> |
| <span id="526">526</span> |
| <span id="527">527</span> |
| <span id="528">528</span> |
| <span id="529">529</span> |
| <span id="530">530</span> |
| <span id="531">531</span> |
| <span id="532">532</span> |
| <span id="533">533</span> |
| <span id="534">534</span> |
| <span id="535">535</span> |
| <span id="536">536</span> |
| <span id="537">537</span> |
| <span id="538">538</span> |
| <span id="539">539</span> |
| </pre><pre class="rust"><code><span class="comment">// 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. |
| |
| </span><span class="doccomment">//! 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 |
| //! |
| //! ```no_run |
| //! use rand_core::{RngCore, SeedableRng}; |
| //! use rand_core::block::{BlockRngCore, BlockRng}; |
| //! |
| //! struct MyRngCore; |
| //! |
| //! impl BlockRngCore for MyRngCore { |
| //! type Item = u32; |
| //! type Results = [u32; 16]; |
| //! |
| //! fn generate(&mut self, results: &mut Self::Results) { |
| //! unimplemented!() |
| //! } |
| //! } |
| //! |
| //! impl SeedableRng for MyRngCore { |
| //! type Seed = [u8; 32]; |
| //! fn from_seed(seed: Self::Seed) -> Self { |
| //! unimplemented!() |
| //! } |
| //! } |
| //! |
| //! // optionally, also implement CryptoRng for MyRngCore |
| //! |
| //! // Final RNG. |
| //! let mut rng = BlockRng::<MyRngCore>::seed_from_u64(0); |
| //! println!("First value: {}", rng.next_u32()); |
| //! ``` |
| //! |
| //! [`BlockRngCore`]: crate::block::BlockRngCore |
| //! [`fill_bytes`]: RngCore::fill_bytes |
| |
| </span><span class="kw">use </span><span class="kw">crate</span>::impls::{fill_via_u32_chunks, fill_via_u64_chunks}; |
| <span class="kw">use crate</span>::{CryptoRng, Error, RngCore, SeedableRng}; |
| <span class="kw">use </span>core::convert::AsRef; |
| <span class="kw">use </span>core::fmt; |
| <span class="attribute">#[cfg(feature = <span class="string">"serde1"</span>)] |
| </span><span class="kw">use </span>serde::{Deserialize, Serialize}; |
| |
| <span class="doccomment">/// 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. |
| </span><span class="kw">pub trait </span>BlockRngCore { |
| <span class="doccomment">/// Results element type, e.g. `u32`. |
| </span><span class="kw">type </span>Item; |
| |
| <span class="doccomment">/// Results type. This is the 'block' an RNG implementing `BlockRngCore` |
| /// generates, which will usually be an array like `[u32; 16]`. |
| </span><span class="kw">type </span>Results: AsRef<[<span class="self">Self</span>::Item]> + AsMut<[<span class="self">Self</span>::Item]> + Default; |
| |
| <span class="doccomment">/// Generate a new block of results. |
| </span><span class="kw">fn </span>generate(<span class="kw-2">&mut </span><span class="self">self</span>, results: <span class="kw-2">&mut </span><span class="self">Self</span>::Results); |
| } |
| |
| <span class="doccomment">/// 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 thrown 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 |
| </span><span class="attribute">#[derive(Clone)] |
| #[cfg_attr(feature = <span class="string">"serde1"</span>, derive(Serialize, Deserialize))] |
| #[cfg_attr( |
| feature = <span class="string">"serde1"</span>, |
| serde( |
| bound = <span class="string">"for<'x> R: Serialize + Deserialize<'x> + Sized, for<'x> R::Results: Serialize + Deserialize<'x>" |
| </span>) |
| )] |
| </span><span class="kw">pub struct </span>BlockRng<R: BlockRngCore + <span class="question-mark">?</span>Sized> { |
| results: R::Results, |
| index: usize, |
| <span class="doccomment">/// The *core* part of the RNG, implementing the `generate` function. |
| </span><span class="kw">pub </span>core: R, |
| } |
| |
| <span class="comment">// Custom Debug implementation that does not expose the contents of `results`. |
| </span><span class="kw">impl</span><R: BlockRngCore + fmt::Debug> fmt::Debug <span class="kw">for </span>BlockRng<R> { |
| <span class="kw">fn </span>fmt(<span class="kw-2">&</span><span class="self">self</span>, fmt: <span class="kw-2">&mut </span>fmt::Formatter) -> fmt::Result { |
| fmt.debug_struct(<span class="string">"BlockRng"</span>) |
| .field(<span class="string">"core"</span>, <span class="kw-2">&</span><span class="self">self</span>.core) |
| .field(<span class="string">"result_len"</span>, <span class="kw-2">&</span><span class="self">self</span>.results.as_ref().len()) |
| .field(<span class="string">"index"</span>, <span class="kw-2">&</span><span class="self">self</span>.index) |
| .finish() |
| } |
| } |
| |
| <span class="kw">impl</span><R: BlockRngCore> BlockRng<R> { |
| <span class="doccomment">/// Create a new `BlockRng` from an existing RNG implementing |
| /// `BlockRngCore`. Results will be generated on first use. |
| </span><span class="attribute">#[inline] |
| </span><span class="kw">pub fn </span>new(core: R) -> BlockRng<R> { |
| <span class="kw">let </span>results_empty = R::Results::default(); |
| BlockRng { |
| core, |
| index: results_empty.as_ref().len(), |
| results: results_empty, |
| } |
| } |
| |
| <span class="doccomment">/// 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. |
| </span><span class="attribute">#[inline(always)] |
| </span><span class="kw">pub fn </span>index(<span class="kw-2">&</span><span class="self">self</span>) -> usize { |
| <span class="self">self</span>.index |
| } |
| |
| <span class="doccomment">/// Reset the number of available results. |
| /// This will force a new set of results to be generated on next use. |
| </span><span class="attribute">#[inline] |
| </span><span class="kw">pub fn </span>reset(<span class="kw-2">&mut </span><span class="self">self</span>) { |
| <span class="self">self</span>.index = <span class="self">self</span>.results.as_ref().len(); |
| } |
| |
| <span class="doccomment">/// Generate a new set of results immediately, setting the index to the |
| /// given value. |
| </span><span class="attribute">#[inline] |
| </span><span class="kw">pub fn </span>generate_and_set(<span class="kw-2">&mut </span><span class="self">self</span>, index: usize) { |
| <span class="macro">assert!</span>(index < <span class="self">self</span>.results.as_ref().len()); |
| <span class="self">self</span>.core.generate(<span class="kw-2">&mut </span><span class="self">self</span>.results); |
| <span class="self">self</span>.index = index; |
| } |
| } |
| |
| <span class="kw">impl</span><R: BlockRngCore<Item = u32>> RngCore <span class="kw">for </span>BlockRng<R> |
| <span class="kw">where |
| </span><R <span class="kw">as </span>BlockRngCore>::Results: AsRef<[u32]> + AsMut<[u32]>, |
| { |
| <span class="attribute">#[inline] |
| </span><span class="kw">fn </span>next_u32(<span class="kw-2">&mut </span><span class="self">self</span>) -> u32 { |
| <span class="kw">if </span><span class="self">self</span>.index >= <span class="self">self</span>.results.as_ref().len() { |
| <span class="self">self</span>.generate_and_set(<span class="number">0</span>); |
| } |
| |
| <span class="kw">let </span>value = <span class="self">self</span>.results.as_ref()[<span class="self">self</span>.index]; |
| <span class="self">self</span>.index += <span class="number">1</span>; |
| value |
| } |
| |
| <span class="attribute">#[inline] |
| </span><span class="kw">fn </span>next_u64(<span class="kw-2">&mut </span><span class="self">self</span>) -> u64 { |
| <span class="kw">let </span>read_u64 = |results: <span class="kw-2">&</span>[u32], index| { |
| <span class="kw">let </span>data = <span class="kw-2">&</span>results[index..=index + <span class="number">1</span>]; |
| u64::from(data[<span class="number">1</span>]) << <span class="number">32 </span>| u64::from(data[<span class="number">0</span>]) |
| }; |
| |
| <span class="kw">let </span>len = <span class="self">self</span>.results.as_ref().len(); |
| |
| <span class="kw">let </span>index = <span class="self">self</span>.index; |
| <span class="kw">if </span>index < len - <span class="number">1 </span>{ |
| <span class="self">self</span>.index += <span class="number">2</span>; |
| <span class="comment">// Read an u64 from the current index |
| </span>read_u64(<span class="self">self</span>.results.as_ref(), index) |
| } <span class="kw">else if </span>index >= len { |
| <span class="self">self</span>.generate_and_set(<span class="number">2</span>); |
| read_u64(<span class="self">self</span>.results.as_ref(), <span class="number">0</span>) |
| } <span class="kw">else </span>{ |
| <span class="kw">let </span>x = u64::from(<span class="self">self</span>.results.as_ref()[len - <span class="number">1</span>]); |
| <span class="self">self</span>.generate_and_set(<span class="number">1</span>); |
| <span class="kw">let </span>y = u64::from(<span class="self">self</span>.results.as_ref()[<span class="number">0</span>]); |
| (y << <span class="number">32</span>) | x |
| } |
| } |
| |
| <span class="attribute">#[inline] |
| </span><span class="kw">fn </span>fill_bytes(<span class="kw-2">&mut </span><span class="self">self</span>, dest: <span class="kw-2">&mut </span>[u8]) { |
| <span class="kw">let </span><span class="kw-2">mut </span>read_len = <span class="number">0</span>; |
| <span class="kw">while </span>read_len < dest.len() { |
| <span class="kw">if </span><span class="self">self</span>.index >= <span class="self">self</span>.results.as_ref().len() { |
| <span class="self">self</span>.generate_and_set(<span class="number">0</span>); |
| } |
| <span class="kw">let </span>(consumed_u32, filled_u8) = |
| fill_via_u32_chunks(<span class="kw-2">&</span><span class="self">self</span>.results.as_ref()[<span class="self">self</span>.index..], <span class="kw-2">&mut </span>dest[read_len..]); |
| |
| <span class="self">self</span>.index += consumed_u32; |
| read_len += filled_u8; |
| } |
| } |
| |
| <span class="attribute">#[inline(always)] |
| </span><span class="kw">fn </span>try_fill_bytes(<span class="kw-2">&mut </span><span class="self">self</span>, dest: <span class="kw-2">&mut </span>[u8]) -> <span class="prelude-ty">Result</span><(), Error> { |
| <span class="self">self</span>.fill_bytes(dest); |
| <span class="prelude-val">Ok</span>(()) |
| } |
| } |
| |
| <span class="kw">impl</span><R: BlockRngCore + SeedableRng> SeedableRng <span class="kw">for </span>BlockRng<R> { |
| <span class="kw">type </span>Seed = R::Seed; |
| |
| <span class="attribute">#[inline(always)] |
| </span><span class="kw">fn </span>from_seed(seed: <span class="self">Self</span>::Seed) -> <span class="self">Self </span>{ |
| <span class="self">Self</span>::new(R::from_seed(seed)) |
| } |
| |
| <span class="attribute">#[inline(always)] |
| </span><span class="kw">fn </span>seed_from_u64(seed: u64) -> <span class="self">Self </span>{ |
| <span class="self">Self</span>::new(R::seed_from_u64(seed)) |
| } |
| |
| <span class="attribute">#[inline(always)] |
| </span><span class="kw">fn </span>from_rng<S: RngCore>(rng: S) -> <span class="prelude-ty">Result</span><<span class="self">Self</span>, Error> { |
| <span class="prelude-val">Ok</span>(<span class="self">Self</span>::new(R::from_rng(rng)<span class="question-mark">?</span>)) |
| } |
| } |
| |
| <span class="doccomment">/// 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 |
| </span><span class="attribute">#[derive(Clone)] |
| #[cfg_attr(feature = <span class="string">"serde1"</span>, derive(Serialize, Deserialize))] |
| </span><span class="kw">pub struct </span>BlockRng64<R: BlockRngCore + <span class="question-mark">?</span>Sized> { |
| results: R::Results, |
| index: usize, |
| half_used: bool, <span class="comment">// true if only half of the previous result is used |
| </span><span class="doccomment">/// The *core* part of the RNG, implementing the `generate` function. |
| </span><span class="kw">pub </span>core: R, |
| } |
| |
| <span class="comment">// Custom Debug implementation that does not expose the contents of `results`. |
| </span><span class="kw">impl</span><R: BlockRngCore + fmt::Debug> fmt::Debug <span class="kw">for </span>BlockRng64<R> { |
| <span class="kw">fn </span>fmt(<span class="kw-2">&</span><span class="self">self</span>, fmt: <span class="kw-2">&mut </span>fmt::Formatter) -> fmt::Result { |
| fmt.debug_struct(<span class="string">"BlockRng64"</span>) |
| .field(<span class="string">"core"</span>, <span class="kw-2">&</span><span class="self">self</span>.core) |
| .field(<span class="string">"result_len"</span>, <span class="kw-2">&</span><span class="self">self</span>.results.as_ref().len()) |
| .field(<span class="string">"index"</span>, <span class="kw-2">&</span><span class="self">self</span>.index) |
| .field(<span class="string">"half_used"</span>, <span class="kw-2">&</span><span class="self">self</span>.half_used) |
| .finish() |
| } |
| } |
| |
| <span class="kw">impl</span><R: BlockRngCore> BlockRng64<R> { |
| <span class="doccomment">/// Create a new `BlockRng` from an existing RNG implementing |
| /// `BlockRngCore`. Results will be generated on first use. |
| </span><span class="attribute">#[inline] |
| </span><span class="kw">pub fn </span>new(core: R) -> BlockRng64<R> { |
| <span class="kw">let </span>results_empty = R::Results::default(); |
| BlockRng64 { |
| core, |
| index: results_empty.as_ref().len(), |
| half_used: <span class="bool-val">false</span>, |
| results: results_empty, |
| } |
| } |
| |
| <span class="doccomment">/// 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. |
| </span><span class="attribute">#[inline(always)] |
| </span><span class="kw">pub fn </span>index(<span class="kw-2">&</span><span class="self">self</span>) -> usize { |
| <span class="self">self</span>.index |
| } |
| |
| <span class="doccomment">/// Reset the number of available results. |
| /// This will force a new set of results to be generated on next use. |
| </span><span class="attribute">#[inline] |
| </span><span class="kw">pub fn </span>reset(<span class="kw-2">&mut </span><span class="self">self</span>) { |
| <span class="self">self</span>.index = <span class="self">self</span>.results.as_ref().len(); |
| <span class="self">self</span>.half_used = <span class="bool-val">false</span>; |
| } |
| |
| <span class="doccomment">/// Generate a new set of results immediately, setting the index to the |
| /// given value. |
| </span><span class="attribute">#[inline] |
| </span><span class="kw">pub fn </span>generate_and_set(<span class="kw-2">&mut </span><span class="self">self</span>, index: usize) { |
| <span class="macro">assert!</span>(index < <span class="self">self</span>.results.as_ref().len()); |
| <span class="self">self</span>.core.generate(<span class="kw-2">&mut </span><span class="self">self</span>.results); |
| <span class="self">self</span>.index = index; |
| <span class="self">self</span>.half_used = <span class="bool-val">false</span>; |
| } |
| } |
| |
| <span class="kw">impl</span><R: BlockRngCore<Item = u64>> RngCore <span class="kw">for </span>BlockRng64<R> |
| <span class="kw">where |
| </span><R <span class="kw">as </span>BlockRngCore>::Results: AsRef<[u64]> + AsMut<[u64]>, |
| { |
| <span class="attribute">#[inline] |
| </span><span class="kw">fn </span>next_u32(<span class="kw-2">&mut </span><span class="self">self</span>) -> u32 { |
| <span class="kw">let </span><span class="kw-2">mut </span>index = <span class="self">self</span>.index - <span class="self">self</span>.half_used <span class="kw">as </span>usize; |
| <span class="kw">if </span>index >= <span class="self">self</span>.results.as_ref().len() { |
| <span class="self">self</span>.core.generate(<span class="kw-2">&mut </span><span class="self">self</span>.results); |
| <span class="self">self</span>.index = <span class="number">0</span>; |
| index = <span class="number">0</span>; |
| <span class="comment">// `self.half_used` is by definition `false` |
| </span><span class="self">self</span>.half_used = <span class="bool-val">false</span>; |
| } |
| |
| <span class="kw">let </span>shift = <span class="number">32 </span>* (<span class="self">self</span>.half_used <span class="kw">as </span>usize); |
| |
| <span class="self">self</span>.half_used = !<span class="self">self</span>.half_used; |
| <span class="self">self</span>.index += <span class="self">self</span>.half_used <span class="kw">as </span>usize; |
| |
| (<span class="self">self</span>.results.as_ref()[index] >> shift) <span class="kw">as </span>u32 |
| } |
| |
| <span class="attribute">#[inline] |
| </span><span class="kw">fn </span>next_u64(<span class="kw-2">&mut </span><span class="self">self</span>) -> u64 { |
| <span class="kw">if </span><span class="self">self</span>.index >= <span class="self">self</span>.results.as_ref().len() { |
| <span class="self">self</span>.core.generate(<span class="kw-2">&mut </span><span class="self">self</span>.results); |
| <span class="self">self</span>.index = <span class="number">0</span>; |
| } |
| |
| <span class="kw">let </span>value = <span class="self">self</span>.results.as_ref()[<span class="self">self</span>.index]; |
| <span class="self">self</span>.index += <span class="number">1</span>; |
| <span class="self">self</span>.half_used = <span class="bool-val">false</span>; |
| value |
| } |
| |
| <span class="attribute">#[inline] |
| </span><span class="kw">fn </span>fill_bytes(<span class="kw-2">&mut </span><span class="self">self</span>, dest: <span class="kw-2">&mut </span>[u8]) { |
| <span class="kw">let </span><span class="kw-2">mut </span>read_len = <span class="number">0</span>; |
| <span class="self">self</span>.half_used = <span class="bool-val">false</span>; |
| <span class="kw">while </span>read_len < dest.len() { |
| <span class="kw">if </span><span class="self">self</span>.index <span class="kw">as </span>usize >= <span class="self">self</span>.results.as_ref().len() { |
| <span class="self">self</span>.core.generate(<span class="kw-2">&mut </span><span class="self">self</span>.results); |
| <span class="self">self</span>.index = <span class="number">0</span>; |
| } |
| |
| <span class="kw">let </span>(consumed_u64, filled_u8) = fill_via_u64_chunks( |
| <span class="kw-2">&</span><span class="self">self</span>.results.as_ref()[<span class="self">self</span>.index <span class="kw">as </span>usize..], |
| <span class="kw-2">&mut </span>dest[read_len..], |
| ); |
| |
| <span class="self">self</span>.index += consumed_u64; |
| read_len += filled_u8; |
| } |
| } |
| |
| <span class="attribute">#[inline(always)] |
| </span><span class="kw">fn </span>try_fill_bytes(<span class="kw-2">&mut </span><span class="self">self</span>, dest: <span class="kw-2">&mut </span>[u8]) -> <span class="prelude-ty">Result</span><(), Error> { |
| <span class="self">self</span>.fill_bytes(dest); |
| <span class="prelude-val">Ok</span>(()) |
| } |
| } |
| |
| <span class="kw">impl</span><R: BlockRngCore + SeedableRng> SeedableRng <span class="kw">for </span>BlockRng64<R> { |
| <span class="kw">type </span>Seed = R::Seed; |
| |
| <span class="attribute">#[inline(always)] |
| </span><span class="kw">fn </span>from_seed(seed: <span class="self">Self</span>::Seed) -> <span class="self">Self </span>{ |
| <span class="self">Self</span>::new(R::from_seed(seed)) |
| } |
| |
| <span class="attribute">#[inline(always)] |
| </span><span class="kw">fn </span>seed_from_u64(seed: u64) -> <span class="self">Self </span>{ |
| <span class="self">Self</span>::new(R::seed_from_u64(seed)) |
| } |
| |
| <span class="attribute">#[inline(always)] |
| </span><span class="kw">fn </span>from_rng<S: RngCore>(rng: S) -> <span class="prelude-ty">Result</span><<span class="self">Self</span>, Error> { |
| <span class="prelude-val">Ok</span>(<span class="self">Self</span>::new(R::from_rng(rng)<span class="question-mark">?</span>)) |
| } |
| } |
| |
| <span class="kw">impl</span><R: BlockRngCore + CryptoRng> CryptoRng <span class="kw">for </span>BlockRng<R> {} |
| |
| <span class="attribute">#[cfg(test)] |
| </span><span class="kw">mod </span>test { |
| <span class="kw">use crate</span>::{SeedableRng, RngCore}; |
| <span class="kw">use </span><span class="kw">crate</span>::block::{BlockRng, BlockRng64, BlockRngCore}; |
| |
| <span class="attribute">#[derive(Debug, Clone)] |
| </span><span class="kw">struct </span>DummyRng { |
| counter: u32, |
| } |
| |
| <span class="kw">impl </span>BlockRngCore <span class="kw">for </span>DummyRng { |
| <span class="kw">type </span>Item = u32; |
| |
| <span class="kw">type </span>Results = [u32; <span class="number">16</span>]; |
| |
| <span class="kw">fn </span>generate(<span class="kw-2">&mut </span><span class="self">self</span>, results: <span class="kw-2">&mut </span><span class="self">Self</span>::Results) { |
| <span class="kw">for </span>r <span class="kw">in </span>results { |
| <span class="kw-2">*</span>r = <span class="self">self</span>.counter; |
| <span class="self">self</span>.counter = <span class="self">self</span>.counter.wrapping_add(<span class="number">3511615421</span>); |
| } |
| } |
| } |
| |
| <span class="kw">impl </span>SeedableRng <span class="kw">for </span>DummyRng { |
| <span class="kw">type </span>Seed = [u8; <span class="number">4</span>]; |
| |
| <span class="kw">fn </span>from_seed(seed: <span class="self">Self</span>::Seed) -> <span class="self">Self </span>{ |
| DummyRng { counter: u32::from_le_bytes(seed) } |
| } |
| } |
| |
| <span class="attribute">#[test] |
| </span><span class="kw">fn </span>blockrng_next_u32_vs_next_u64() { |
| <span class="kw">let </span><span class="kw-2">mut </span>rng1 = BlockRng::<DummyRng>::from_seed([<span class="number">1</span>, <span class="number">2</span>, <span class="number">3</span>, <span class="number">4</span>]); |
| <span class="kw">let </span><span class="kw-2">mut </span>rng2 = rng1.clone(); |
| <span class="kw">let </span><span class="kw-2">mut </span>rng3 = rng1.clone(); |
| |
| <span class="kw">let </span><span class="kw-2">mut </span>a = [<span class="number">0</span>; <span class="number">16</span>]; |
| (<span class="kw-2">&mut </span>a[..<span class="number">4</span>]).copy_from_slice(<span class="kw-2">&</span>rng1.next_u32().to_le_bytes()); |
| (<span class="kw-2">&mut </span>a[<span class="number">4</span>..<span class="number">12</span>]).copy_from_slice(<span class="kw-2">&</span>rng1.next_u64().to_le_bytes()); |
| (<span class="kw-2">&mut </span>a[<span class="number">12</span>..]).copy_from_slice(<span class="kw-2">&</span>rng1.next_u32().to_le_bytes()); |
| |
| <span class="kw">let </span><span class="kw-2">mut </span>b = [<span class="number">0</span>; <span class="number">16</span>]; |
| (<span class="kw-2">&mut </span>b[..<span class="number">4</span>]).copy_from_slice(<span class="kw-2">&</span>rng2.next_u32().to_le_bytes()); |
| (<span class="kw-2">&mut </span>b[<span class="number">4</span>..<span class="number">8</span>]).copy_from_slice(<span class="kw-2">&</span>rng2.next_u32().to_le_bytes()); |
| (<span class="kw-2">&mut </span>b[<span class="number">8</span>..]).copy_from_slice(<span class="kw-2">&</span>rng2.next_u64().to_le_bytes()); |
| <span class="macro">assert_eq!</span>(a, b); |
| |
| <span class="kw">let </span><span class="kw-2">mut </span>c = [<span class="number">0</span>; <span class="number">16</span>]; |
| (<span class="kw-2">&mut </span>c[..<span class="number">8</span>]).copy_from_slice(<span class="kw-2">&</span>rng3.next_u64().to_le_bytes()); |
| (<span class="kw-2">&mut </span>c[<span class="number">8</span>..<span class="number">12</span>]).copy_from_slice(<span class="kw-2">&</span>rng3.next_u32().to_le_bytes()); |
| (<span class="kw-2">&mut </span>c[<span class="number">12</span>..]).copy_from_slice(<span class="kw-2">&</span>rng3.next_u32().to_le_bytes()); |
| <span class="macro">assert_eq!</span>(a, c); |
| } |
| |
| <span class="attribute">#[derive(Debug, Clone)] |
| </span><span class="kw">struct </span>DummyRng64 { |
| counter: u64, |
| } |
| |
| <span class="kw">impl </span>BlockRngCore <span class="kw">for </span>DummyRng64 { |
| <span class="kw">type </span>Item = u64; |
| |
| <span class="kw">type </span>Results = [u64; <span class="number">8</span>]; |
| |
| <span class="kw">fn </span>generate(<span class="kw-2">&mut </span><span class="self">self</span>, results: <span class="kw-2">&mut </span><span class="self">Self</span>::Results) { |
| <span class="kw">for </span>r <span class="kw">in </span>results { |
| <span class="kw-2">*</span>r = <span class="self">self</span>.counter; |
| <span class="self">self</span>.counter = <span class="self">self</span>.counter.wrapping_add(<span class="number">2781463553396133981</span>); |
| } |
| } |
| } |
| |
| <span class="kw">impl </span>SeedableRng <span class="kw">for </span>DummyRng64 { |
| <span class="kw">type </span>Seed = [u8; <span class="number">8</span>]; |
| |
| <span class="kw">fn </span>from_seed(seed: <span class="self">Self</span>::Seed) -> <span class="self">Self </span>{ |
| DummyRng64 { counter: u64::from_le_bytes(seed) } |
| } |
| } |
| |
| <span class="attribute">#[test] |
| </span><span class="kw">fn </span>blockrng64_next_u32_vs_next_u64() { |
| <span class="kw">let </span><span class="kw-2">mut </span>rng1 = BlockRng64::<DummyRng64>::from_seed([<span class="number">1</span>, <span class="number">2</span>, <span class="number">3</span>, <span class="number">4</span>, <span class="number">5</span>, <span class="number">6</span>, <span class="number">7</span>, <span class="number">8</span>]); |
| <span class="kw">let </span><span class="kw-2">mut </span>rng2 = rng1.clone(); |
| <span class="kw">let </span><span class="kw-2">mut </span>rng3 = rng1.clone(); |
| |
| <span class="kw">let </span><span class="kw-2">mut </span>a = [<span class="number">0</span>; <span class="number">16</span>]; |
| (<span class="kw-2">&mut </span>a[..<span class="number">4</span>]).copy_from_slice(<span class="kw-2">&</span>rng1.next_u32().to_le_bytes()); |
| (<span class="kw-2">&mut </span>a[<span class="number">4</span>..<span class="number">12</span>]).copy_from_slice(<span class="kw-2">&</span>rng1.next_u64().to_le_bytes()); |
| (<span class="kw-2">&mut </span>a[<span class="number">12</span>..]).copy_from_slice(<span class="kw-2">&</span>rng1.next_u32().to_le_bytes()); |
| |
| <span class="kw">let </span><span class="kw-2">mut </span>b = [<span class="number">0</span>; <span class="number">16</span>]; |
| (<span class="kw-2">&mut </span>b[..<span class="number">4</span>]).copy_from_slice(<span class="kw-2">&</span>rng2.next_u32().to_le_bytes()); |
| (<span class="kw-2">&mut </span>b[<span class="number">4</span>..<span class="number">8</span>]).copy_from_slice(<span class="kw-2">&</span>rng2.next_u32().to_le_bytes()); |
| (<span class="kw-2">&mut </span>b[<span class="number">8</span>..]).copy_from_slice(<span class="kw-2">&</span>rng2.next_u64().to_le_bytes()); |
| <span class="macro">assert_ne!</span>(a, b); |
| <span class="macro">assert_eq!</span>(<span class="kw-2">&</span>a[..<span class="number">4</span>], <span class="kw-2">&</span>b[..<span class="number">4</span>]); |
| <span class="macro">assert_eq!</span>(<span class="kw-2">&</span>a[<span class="number">4</span>..<span class="number">12</span>], <span class="kw-2">&</span>b[<span class="number">8</span>..]); |
| |
| <span class="kw">let </span><span class="kw-2">mut </span>c = [<span class="number">0</span>; <span class="number">16</span>]; |
| (<span class="kw-2">&mut </span>c[..<span class="number">8</span>]).copy_from_slice(<span class="kw-2">&</span>rng3.next_u64().to_le_bytes()); |
| (<span class="kw-2">&mut </span>c[<span class="number">8</span>..<span class="number">12</span>]).copy_from_slice(<span class="kw-2">&</span>rng3.next_u32().to_le_bytes()); |
| (<span class="kw-2">&mut </span>c[<span class="number">12</span>..]).copy_from_slice(<span class="kw-2">&</span>rng3.next_u32().to_le_bytes()); |
| <span class="macro">assert_eq!</span>(b, c); |
| } |
| } |
| </code></pre></div> |
| </section></div></main><div id="rustdoc-vars" data-root-path="../../" data-current-crate="rand_core" data-themes="ayu,dark,light" data-resource-suffix="" data-rustdoc-version="1.66.0-nightly (5c8bff74b 2022-10-21)" ></div></body></html> |
