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| </pre><pre class="rust"><code><span class="comment">// Copyright 2018 Developers of the Rand project. |
| // Copyright 2013 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. |
| |
| </span><span class="doccomment">//! A wrapper around any Read to treat it as an RNG. |
| |
| </span><span class="attribute">#![allow(deprecated)] |
| |
| </span><span class="kw">use </span>std::fmt; |
| <span class="kw">use </span>std::io::Read; |
| |
| <span class="kw">use </span>rand_core::{impls, Error, RngCore}; |
| |
| |
| <span class="doccomment">/// An RNG that reads random bytes straight from any type supporting |
| /// [`std::io::Read`], for example files. |
| /// |
| /// This will work best with an infinite reader, but that is not required. |
| /// |
| /// This can be used with `/dev/urandom` on Unix but it is recommended to use |
| /// [`OsRng`] instead. |
| /// |
| /// # Panics |
| /// |
| /// `ReadRng` uses [`std::io::Read::read_exact`], which retries on interrupts. |
| /// All other errors from the underlying reader, including when it does not |
| /// have enough data, will only be reported through [`try_fill_bytes`]. |
| /// The other [`RngCore`] methods will panic in case of an error. |
| /// |
| /// [`OsRng`]: crate::rngs::OsRng |
| /// [`try_fill_bytes`]: RngCore::try_fill_bytes |
| </span><span class="attribute">#[derive(Debug)] |
| #[deprecated(since=<span class="string">"0.8.4"</span>, note=<span class="string">"removal due to lack of usage"</span>)] |
| </span><span class="kw">pub struct </span>ReadRng<R> { |
| reader: R, |
| } |
| |
| <span class="kw">impl</span><R: Read> ReadRng<R> { |
| <span class="doccomment">/// Create a new `ReadRng` from a `Read`. |
| </span><span class="kw">pub fn </span>new(r: R) -> ReadRng<R> { |
| ReadRng { reader: r } |
| } |
| } |
| |
| <span class="kw">impl</span><R: Read> RngCore <span class="kw">for </span>ReadRng<R> { |
| <span class="kw">fn </span>next_u32(<span class="kw-2">&mut </span><span class="self">self</span>) -> u32 { |
| impls::next_u32_via_fill(<span class="self">self</span>) |
| } |
| |
| <span class="kw">fn </span>next_u64(<span class="kw-2">&mut </span><span class="self">self</span>) -> u64 { |
| impls::next_u64_via_fill(<span class="self">self</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="self">self</span>.try_fill_bytes(dest).unwrap_or_else(|err| { |
| <span class="macro">panic!</span>( |
| <span class="string">"reading random bytes from Read implementation failed; error: {}"</span>, |
| err |
| ) |
| }); |
| } |
| |
| <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="kw">if </span>dest.is_empty() { |
| <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>.reader |
| .read_exact(dest) |
| .map_err(|e| Error::new(ReadError(e))) |
| } |
| } |
| |
| <span class="doccomment">/// `ReadRng` error type |
| </span><span class="attribute">#[derive(Debug)] |
| #[deprecated(since=<span class="string">"0.8.4"</span>)] |
| </span><span class="kw">pub struct </span>ReadError(std::io::Error); |
| |
| <span class="kw">impl </span>fmt::Display <span class="kw">for </span>ReadError { |
| <span class="kw">fn </span>fmt(<span class="kw-2">&</span><span class="self">self</span>, f: <span class="kw-2">&mut </span>fmt::Formatter) -> fmt::Result { |
| <span class="macro">write!</span>(f, <span class="string">"ReadError: {}"</span>, <span class="self">self</span>.<span class="number">0</span>) |
| } |
| } |
| |
| <span class="kw">impl </span>std::error::Error <span class="kw">for </span>ReadError { |
| <span class="kw">fn </span>source(<span class="kw-2">&</span><span class="self">self</span>) -> <span class="prelude-ty">Option</span><<span class="kw-2">&</span>(<span class="kw">dyn </span>std::error::Error + <span class="lifetime">'static</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">#[cfg(test)] |
| </span><span class="kw">mod </span>test { |
| <span class="kw">use </span>std::println; |
| |
| <span class="kw">use </span><span class="kw">super</span>::ReadRng; |
| <span class="kw">use </span><span class="kw">crate</span>::RngCore; |
| |
| <span class="attribute">#[test] |
| </span><span class="kw">fn </span>test_reader_rng_u64() { |
| <span class="comment">// transmute from the target to avoid endianness concerns. |
| </span><span class="attribute">#[rustfmt::skip] |
| </span><span class="kw">let </span>v = [<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>rng = ReadRng::new(<span class="kw-2">&</span>v[..]); |
| |
| <span class="macro">assert_eq!</span>(rng.next_u64(), <span class="number">1 </span><< <span class="number">56</span>); |
| <span class="macro">assert_eq!</span>(rng.next_u64(), (<span class="number">2 </span><< <span class="number">56</span>) + (<span class="number">3 </span><< <span class="number">32</span>) + (<span class="number">4 </span><< <span class="number">8</span>)); |
| <span class="macro">assert_eq!</span>(rng.next_u64(), <span class="number">5</span>); |
| } |
| |
| <span class="attribute">#[test] |
| </span><span class="kw">fn </span>test_reader_rng_u32() { |
| <span class="kw">let </span>v = [<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>rng = ReadRng::new(<span class="kw-2">&</span>v[..]); |
| |
| <span class="macro">assert_eq!</span>(rng.next_u32(), <span class="number">1 </span><< <span class="number">24</span>); |
| <span class="macro">assert_eq!</span>(rng.next_u32(), <span class="number">2 </span><< <span class="number">16</span>); |
| <span class="macro">assert_eq!</span>(rng.next_u32(), <span class="number">3</span>); |
| } |
| |
| <span class="attribute">#[test] |
| </span><span class="kw">fn </span>test_reader_rng_fill_bytes() { |
| <span class="kw">let </span>v = [<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>w = [<span class="number">0u8</span>; <span class="number">8</span>]; |
| |
| <span class="kw">let </span><span class="kw-2">mut </span>rng = ReadRng::new(<span class="kw-2">&</span>v[..]); |
| rng.fill_bytes(<span class="kw-2">&mut </span>w); |
| |
| <span class="macro">assert!</span>(v == w); |
| } |
| |
| <span class="attribute">#[test] |
| </span><span class="kw">fn </span>test_reader_rng_insufficient_bytes() { |
| <span class="kw">let </span>v = [<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>w = [<span class="number">0u8</span>; <span class="number">9</span>]; |
| |
| <span class="kw">let </span><span class="kw-2">mut </span>rng = ReadRng::new(<span class="kw-2">&</span>v[..]); |
| |
| <span class="kw">let </span>result = rng.try_fill_bytes(<span class="kw-2">&mut </span>w); |
| <span class="macro">assert!</span>(result.is_err()); |
| <span class="macro">println!</span>(<span class="string">"Error: {}"</span>, result.unwrap_err()); |
| } |
| } |
| </code></pre></div> |
| </section></div></main><div id="rustdoc-vars" data-root-path="../../../../" data-current-crate="rand" data-themes="ayu,dark,light" data-resource-suffix="" data-rustdoc-version="1.66.0-nightly (5c8bff74b 2022-10-21)" ></div></body></html> |
