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| </pre><pre class="rust"><code><span class="comment">// Copyright 2018 Developers of the Rand project.</span> |
| <span class="comment">// Copyright 2013 The Rust Project Developers.</span> |
| <span class="comment">//</span> |
| <span class="comment">// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or</span> |
| <span class="comment">// https://www.apache.org/licenses/LICENSE-2.0> or the MIT license</span> |
| <span class="comment">// <LICENSE-MIT or https://opensource.org/licenses/MIT>, at your</span> |
| <span class="comment">// option. This file may not be copied, modified, or distributed</span> |
| <span class="comment">// except according to those terms.</span> |
| |
| <span class="doccomment">//! A wrapper around any Read to treat it as an RNG.</span> |
| |
| <span class="attribute">#![<span class="ident">allow</span>(<span class="ident">deprecated</span>)]</span> |
| |
| <span class="kw">use</span> <span class="ident">std::fmt</span>; |
| <span class="kw">use</span> <span class="ident">std::io::Read</span>; |
| |
| <span class="kw">use</span> <span class="ident">rand_core</span>::{<span class="ident">impls</span>, <span class="ident">Error</span>, <span class="ident">RngCore</span>}; |
| |
| |
| <span class="doccomment">/// An RNG that reads random bytes straight from any type supporting</span> |
| <span class="doccomment">/// [`std::io::Read`], for example files.</span> |
| <span class="doccomment">///</span> |
| <span class="doccomment">/// This will work best with an infinite reader, but that is not required.</span> |
| <span class="doccomment">///</span> |
| <span class="doccomment">/// This can be used with `/dev/urandom` on Unix but it is recommended to use</span> |
| <span class="doccomment">/// [`OsRng`] instead.</span> |
| <span class="doccomment">///</span> |
| <span class="doccomment">/// # Panics</span> |
| <span class="doccomment">///</span> |
| <span class="doccomment">/// `ReadRng` uses [`std::io::Read::read_exact`], which retries on interrupts.</span> |
| <span class="doccomment">/// All other errors from the underlying reader, including when it does not</span> |
| <span class="doccomment">/// have enough data, will only be reported through [`try_fill_bytes`].</span> |
| <span class="doccomment">/// The other [`RngCore`] methods will panic in case of an error.</span> |
| <span class="doccomment">///</span> |
| <span class="doccomment">/// [`OsRng`]: crate::rngs::OsRng</span> |
| <span class="doccomment">/// [`try_fill_bytes`]: RngCore::try_fill_bytes</span> |
| <span class="attribute">#[<span class="ident">derive</span>(<span class="ident">Debug</span>)]</span> |
| <span class="attribute">#[<span class="ident">deprecated</span>(<span class="ident">since</span><span class="op">=</span><span class="string">"0.8.4"</span>, <span class="ident">note</span><span class="op">=</span><span class="string">"removal due to lack of usage"</span>)]</span> |
| <span class="kw">pub</span> <span class="kw">struct</span> <span class="ident">ReadRng</span><span class="op"><</span><span class="ident">R</span><span class="op">></span> { |
| <span class="ident">reader</span>: <span class="ident">R</span>, |
| } |
| |
| <span class="kw">impl</span><span class="op"><</span><span class="ident">R</span>: <span class="ident">Read</span><span class="op">></span> <span class="ident">ReadRng</span><span class="op"><</span><span class="ident">R</span><span class="op">></span> { |
| <span class="doccomment">/// Create a new `ReadRng` from a `Read`.</span> |
| <span class="kw">pub</span> <span class="kw">fn</span> <span class="ident">new</span>(<span class="ident">r</span>: <span class="ident">R</span>) -> <span class="ident">ReadRng</span><span class="op"><</span><span class="ident">R</span><span class="op">></span> { |
| <span class="ident">ReadRng</span> { <span class="ident">reader</span>: <span class="ident">r</span> } |
| } |
| } |
| |
| <span class="kw">impl</span><span class="op"><</span><span class="ident">R</span>: <span class="ident">Read</span><span class="op">></span> <span class="ident">RngCore</span> <span class="kw">for</span> <span class="ident">ReadRng</span><span class="op"><</span><span class="ident">R</span><span class="op">></span> { |
| <span class="kw">fn</span> <span class="ident">next_u32</span>(<span class="kw-2">&mut</span> <span class="self">self</span>) -> <span class="ident">u32</span> { |
| <span class="ident">impls::next_u32_via_fill</span>(<span class="self">self</span>) |
| } |
| |
| <span class="kw">fn</span> <span class="ident">next_u64</span>(<span class="kw-2">&mut</span> <span class="self">self</span>) -> <span class="ident">u64</span> { |
| <span class="ident">impls::next_u64_via_fill</span>(<span class="self">self</span>) |
| } |
| |
| <span class="kw">fn</span> <span class="ident">fill_bytes</span>(<span class="kw-2">&mut</span> <span class="self">self</span>, <span class="ident">dest</span>: <span class="kw-2">&mut</span> [<span class="ident">u8</span>]) { |
| <span class="self">self</span>.<span class="ident">try_fill_bytes</span>(<span class="ident">dest</span>).<span class="ident">unwrap_or_else</span>(<span class="op">|</span><span class="ident">err</span><span class="op">|</span> { |
| <span class="macro">panic!</span>( |
| <span class="string">"reading random bytes from Read implementation failed; error: {}"</span>, |
| <span class="ident">err</span> |
| ) |
| }); |
| } |
| |
| <span class="kw">fn</span> <span class="ident">try_fill_bytes</span>(<span class="kw-2">&mut</span> <span class="self">self</span>, <span class="ident">dest</span>: <span class="kw-2">&mut</span> [<span class="ident">u8</span>]) -> <span class="prelude-ty">Result</span><span class="op"><</span>(), <span class="ident">Error</span><span class="op">></span> { |
| <span class="kw">if</span> <span class="ident">dest</span>.<span class="ident">is_empty</span>() { |
| <span class="kw">return</span> <span class="prelude-val">Ok</span>(()); |
| } |
| <span class="comment">// Use `std::io::read_exact`, which retries on `ErrorKind::Interrupted`.</span> |
| <span class="self">self</span>.<span class="ident">reader</span> |
| .<span class="ident">read_exact</span>(<span class="ident">dest</span>) |
| .<span class="ident">map_err</span>(<span class="op">|</span><span class="ident">e</span><span class="op">|</span> <span class="ident">Error::new</span>(<span class="ident">ReadError</span>(<span class="ident">e</span>))) |
| } |
| } |
| |
| <span class="doccomment">/// `ReadRng` error type</span> |
| <span class="attribute">#[<span class="ident">derive</span>(<span class="ident">Debug</span>)]</span> |
| <span class="attribute">#[<span class="ident">deprecated</span>(<span class="ident">since</span><span class="op">=</span><span class="string">"0.8.4"</span>)]</span> |
| <span class="kw">pub</span> <span class="kw">struct</span> <span class="ident">ReadError</span>(<span class="ident">std::io::Error</span>); |
| |
| <span class="kw">impl</span> <span class="ident">fmt::Display</span> <span class="kw">for</span> <span class="ident">ReadError</span> { |
| <span class="kw">fn</span> <span class="ident">fmt</span>(<span class="kw-2">&</span><span class="self">self</span>, <span class="ident">f</span>: <span class="kw-2">&mut</span> <span class="ident">fmt::Formatter</span>) -> <span class="ident">fmt::Result</span> { |
| <span class="macro">write!</span>(<span class="ident">f</span>, <span class="string">"ReadError: {}"</span>, <span class="self">self</span>.<span class="number">0</span>) |
| } |
| } |
| |
| <span class="kw">impl</span> <span class="ident">std::error::Error</span> <span class="kw">for</span> <span class="ident">ReadError</span> { |
| <span class="kw">fn</span> <span class="ident">source</span>(<span class="kw-2">&</span><span class="self">self</span>) -> <span class="prelude-ty">Option</span><span class="op"><</span><span class="kw-2">&</span>(<span class="kw">dyn</span> <span class="ident">std::error::Error</span> <span class="op">+</span> <span class="lifetime">'static</span>)<span class="op">></span> { |
| <span class="prelude-val">Some</span>(<span class="kw-2">&</span><span class="self">self</span>.<span class="number">0</span>) |
| } |
| } |
| |
| |
| <span class="attribute">#[<span class="ident">cfg</span>(<span class="ident">test</span>)]</span> |
| <span class="kw">mod</span> <span class="ident">test</span> { |
| <span class="kw">use</span> <span class="ident">std::println</span>; |
| |
| <span class="kw">use</span> <span class="ident"><span class="kw">super</span>::ReadRng</span>; |
| <span class="kw">use</span> <span class="ident"><span class="kw">crate</span>::RngCore</span>; |
| |
| <span class="attribute">#[<span class="ident">test</span>]</span> |
| <span class="kw">fn</span> <span class="ident">test_reader_rng_u64</span>() { |
| <span class="comment">// transmute from the target to avoid endianness concerns.</span> |
| <span class="attribute">#[<span class="ident">rustfmt::skip</span>]</span> |
| <span class="kw">let</span> <span class="ident">v</span> <span class="op">=</span> [<span class="number">0u8</span>, <span class="number">0</span>, <span class="number">0</span>, <span class="number">0</span>, <span class="number">0</span>, <span class="number">0</span>, <span class="number">0</span>, <span class="number">1</span>, |
| <span class="number">0</span>, <span class="number">4</span>, <span class="number">0</span>, <span class="number">0</span>, <span class="number">3</span>, <span class="number">0</span>, <span class="number">0</span>, <span class="number">2</span>, |
| <span class="number">5</span>, <span class="number">0</span>, <span class="number">0</span>, <span class="number">0</span>, <span class="number">0</span>, <span class="number">0</span>, <span class="number">0</span>, <span class="number">0</span>]; |
| <span class="kw">let</span> <span class="kw-2">mut</span> <span class="ident">rng</span> <span class="op">=</span> <span class="ident">ReadRng::new</span>(<span class="kw-2">&</span><span class="ident">v</span>[..]); |
| |
| <span class="macro">assert_eq!</span>(<span class="ident">rng</span>.<span class="ident">next_u64</span>(), <span class="number">1</span> <span class="op"><</span><span class="op"><</span> <span class="number">56</span>); |
| <span class="macro">assert_eq!</span>(<span class="ident">rng</span>.<span class="ident">next_u64</span>(), (<span class="number">2</span> <span class="op"><</span><span class="op"><</span> <span class="number">56</span>) <span class="op">+</span> (<span class="number">3</span> <span class="op"><</span><span class="op"><</span> <span class="number">32</span>) <span class="op">+</span> (<span class="number">4</span> <span class="op"><</span><span class="op"><</span> <span class="number">8</span>)); |
| <span class="macro">assert_eq!</span>(<span class="ident">rng</span>.<span class="ident">next_u64</span>(), <span class="number">5</span>); |
| } |
| |
| <span class="attribute">#[<span class="ident">test</span>]</span> |
| <span class="kw">fn</span> <span class="ident">test_reader_rng_u32</span>() { |
| <span class="kw">let</span> <span class="ident">v</span> <span class="op">=</span> [<span class="number">0u8</span>, <span class="number">0</span>, <span class="number">0</span>, <span class="number">1</span>, <span class="number">0</span>, <span class="number">0</span>, <span class="number">2</span>, <span class="number">0</span>, <span class="number">3</span>, <span class="number">0</span>, <span class="number">0</span>, <span class="number">0</span>]; |
| <span class="kw">let</span> <span class="kw-2">mut</span> <span class="ident">rng</span> <span class="op">=</span> <span class="ident">ReadRng::new</span>(<span class="kw-2">&</span><span class="ident">v</span>[..]); |
| |
| <span class="macro">assert_eq!</span>(<span class="ident">rng</span>.<span class="ident">next_u32</span>(), <span class="number">1</span> <span class="op"><</span><span class="op"><</span> <span class="number">24</span>); |
| <span class="macro">assert_eq!</span>(<span class="ident">rng</span>.<span class="ident">next_u32</span>(), <span class="number">2</span> <span class="op"><</span><span class="op"><</span> <span class="number">16</span>); |
| <span class="macro">assert_eq!</span>(<span class="ident">rng</span>.<span class="ident">next_u32</span>(), <span class="number">3</span>); |
| } |
| |
| <span class="attribute">#[<span class="ident">test</span>]</span> |
| <span class="kw">fn</span> <span class="ident">test_reader_rng_fill_bytes</span>() { |
| <span class="kw">let</span> <span class="ident">v</span> <span class="op">=</span> [<span class="number">1u8</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> <span class="ident">w</span> <span class="op">=</span> [<span class="number">0u8</span>; <span class="number">8</span>]; |
| |
| <span class="kw">let</span> <span class="kw-2">mut</span> <span class="ident">rng</span> <span class="op">=</span> <span class="ident">ReadRng::new</span>(<span class="kw-2">&</span><span class="ident">v</span>[..]); |
| <span class="ident">rng</span>.<span class="ident">fill_bytes</span>(<span class="kw-2">&mut</span> <span class="ident">w</span>); |
| |
| <span class="macro">assert!</span>(<span class="ident">v</span> <span class="op">==</span> <span class="ident">w</span>); |
| } |
| |
| <span class="attribute">#[<span class="ident">test</span>]</span> |
| <span class="kw">fn</span> <span class="ident">test_reader_rng_insufficient_bytes</span>() { |
| <span class="kw">let</span> <span class="ident">v</span> <span class="op">=</span> [<span class="number">1u8</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> <span class="ident">w</span> <span class="op">=</span> [<span class="number">0u8</span>; <span class="number">9</span>]; |
| |
| <span class="kw">let</span> <span class="kw-2">mut</span> <span class="ident">rng</span> <span class="op">=</span> <span class="ident">ReadRng::new</span>(<span class="kw-2">&</span><span class="ident">v</span>[..]); |
| |
| <span class="kw">let</span> <span class="ident">result</span> <span class="op">=</span> <span class="ident">rng</span>.<span class="ident">try_fill_bytes</span>(<span class="kw-2">&mut</span> <span class="ident">w</span>); |
| <span class="macro">assert!</span>(<span class="ident">result</span>.<span class="ident">is_err</span>()); |
| <span class="macro">println!</span>(<span class="string">"Error: {}"</span>, <span class="ident">result</span>.<span class="ident">unwrap_err</span>()); |
| } |
| } |
| </code></pre></div> |
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