| <!DOCTYPE html><html lang="en"><head><meta charset="utf-8"><meta name="viewport" content="width=device-width, initial-scale=1.0"><meta name="generator" content="rustdoc"><meta name="description" content="Source of the Rust file `/root/.cargo/registry/src/github.com-1ecc6299db9ec823/integer-encoding-1.1.7/src/reader.rs`."><meta name="keywords" content="rust, rustlang, rust-lang"><title>reader.rs - source</title><link rel="preload" as="font" type="font/woff2" crossorigin href="../../SourceSerif4-Regular.ttf.woff2"><link rel="preload" as="font" type="font/woff2" crossorigin href="../../FiraSans-Regular.woff2"><link rel="preload" as="font" type="font/woff2" crossorigin href="../../FiraSans-Medium.woff2"><link rel="preload" as="font" type="font/woff2" crossorigin href="../../SourceCodePro-Regular.ttf.woff2"><link rel="preload" as="font" type="font/woff2" crossorigin href="../../SourceSerif4-Bold.ttf.woff2"><link rel="preload" as="font" type="font/woff2" crossorigin href="../../SourceCodePro-Semibold.ttf.woff2"><link rel="stylesheet" href="../../normalize.css"><link rel="stylesheet" href="../../rustdoc.css" id="mainThemeStyle"><link rel="stylesheet" href="../../ayu.css" disabled><link rel="stylesheet" href="../../dark.css" disabled><link rel="stylesheet" href="../../light.css" id="themeStyle"><script id="default-settings" ></script><script src="../../storage.js"></script><script defer src="../../source-script.js"></script><script defer src="../../source-files.js"></script><script defer src="../../main.js"></script><noscript><link rel="stylesheet" href="../../noscript.css"></noscript><link rel="alternate icon" type="image/png" href="../../favicon-16x16.png"><link rel="alternate icon" type="image/png" href="../../favicon-32x32.png"><link rel="icon" type="image/svg+xml" href="../../favicon.svg"></head><body class="rustdoc source"><!--[if lte IE 11]><div class="warning">This old browser is unsupported and will most likely display funky things.</div><![endif]--><nav class="sidebar"><a class="sidebar-logo" href="../../integer_encoding/index.html"><div class="logo-container"><img class="rust-logo" src="../../rust-logo.svg" alt="logo"></div></a></nav><main><div class="width-limiter"><nav class="sub"><a class="sub-logo-container" href="../../integer_encoding/index.html"><img class="rust-logo" src="../../rust-logo.svg" alt="logo"></a><form class="search-form"><div class="search-container"><span></span><input class="search-input" name="search" autocomplete="off" spellcheck="false" placeholder="Click or press ‘S’ to search, ‘?’ for more options…" type="search"><div id="help-button" title="help" tabindex="-1"><a href="../../help.html">?</a></div><div id="settings-menu" tabindex="-1"><a href="../../settings.html" title="settings"><img width="22" height="22" alt="Change settings" src="../../wheel.svg"></a></div></div></form></nav><section id="main-content" class="content"><div class="example-wrap"><pre class="src-line-numbers"><span id="1">1</span> |
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| </pre><pre class="rust"><code><span class="kw">use </span>std::io; |
| <span class="kw">use </span>std::io::{Read, <span class="prelude-ty">Result</span>}; |
| |
| <span class="kw">use </span><span class="kw">crate</span>::fixed::FixedInt; |
| <span class="kw">use </span><span class="kw">crate</span>::varint::{VarInt, MSB}; |
| |
| <span class="attribute">#[cfg(feature = <span class="string">"tokio_async"</span>)] |
| </span><span class="kw">use </span>tokio::{io::AsyncReadExt, prelude::<span class="kw-2">*</span>}; |
| |
| <span class="attribute">#[cfg(feature = <span class="string">"futures_async"</span>)] |
| </span><span class="kw">use </span>futures_util::{io::AsyncReadExt, io::AsyncRead}; |
| |
| <span class="doccomment">/// A trait for reading VarInts from any other `Reader`. |
| /// |
| /// It's recommended to use a buffered reader, as many small reads will happen. |
| </span><span class="kw">pub trait </span>VarIntReader { |
| <span class="doccomment">/// Returns either the decoded integer, or an error. |
| /// |
| /// In general, this always reads a whole varint. If the encoded varint's value is bigger |
| /// than the valid value range of `VI`, then the value is truncated. |
| /// |
| /// On EOF, an io::Error with io::ErrorKind::UnexpectedEof is returned. |
| </span><span class="kw">fn </span>read_varint<VI: VarInt>(<span class="kw-2">&mut </span><span class="self">self</span>) -> <span class="prelude-ty">Result</span><VI>; |
| } |
| |
| <span class="attribute">#[cfg(any(feature = <span class="string">"tokio_async"</span>, feature = <span class="string">"futures_async"</span>))] |
| </span><span class="doccomment">/// Like a VarIntReader, but returns a future. |
| </span><span class="attribute">#[async_trait::async_trait] |
| </span><span class="kw">pub trait </span>VarIntAsyncReader { |
| <span class="kw">async fn </span>read_varint_async<VI: VarInt>(<span class="kw-2">&mut </span><span class="self">self</span>) -> <span class="prelude-ty">Result</span><VI>; |
| } |
| |
| <span class="doccomment">/// VarIntProcessor encapsulates the logic for decoding a VarInt byte-by-byte. |
| </span><span class="attribute">#[derive(Default)] |
| </span><span class="kw">pub struct </span>VarIntProcessor { |
| buf: [u8; <span class="number">10</span>], |
| i: usize, |
| } |
| |
| <span class="kw">impl </span>VarIntProcessor { |
| <span class="kw">fn </span>push(<span class="kw-2">&mut </span><span class="self">self</span>, b: u8) -> <span class="prelude-ty">Result</span><()> { |
| <span class="kw">if </span><span class="self">self</span>.i >= <span class="number">10 </span>{ |
| <span class="kw">return </span><span class="prelude-val">Err</span>(io::Error::new( |
| io::ErrorKind::InvalidData, |
| <span class="string">"Unterminated varint"</span>, |
| )); |
| } |
| <span class="self">self</span>.buf[<span class="self">self</span>.i] = b; |
| <span class="self">self</span>.i += <span class="number">1</span>; |
| <span class="prelude-val">Ok</span>(()) |
| } |
| <span class="kw">fn </span>finished(<span class="kw-2">&</span><span class="self">self</span>) -> bool { |
| (<span class="self">self</span>.i > <span class="number">0 </span>&& (<span class="self">self</span>.buf[<span class="self">self</span>.i - <span class="number">1</span>] & MSB == <span class="number">0</span>)) |
| } |
| <span class="kw">fn </span>decode<VI: VarInt>(<span class="kw-2">&</span><span class="self">self</span>) -> VI { |
| VI::decode_var(<span class="kw-2">&</span><span class="self">self</span>.buf[<span class="number">0</span>..<span class="self">self</span>.i]).<span class="number">0 |
| </span>} |
| } |
| |
| <span class="attribute">#[cfg(any(feature = <span class="string">"tokio_async"</span>, feature = <span class="string">"futures_async"</span>))] |
| #[async_trait::async_trait] |
| </span><span class="kw">impl</span><AR: AsyncRead + Unpin + Send> VarIntAsyncReader <span class="kw">for </span>AR { |
| <span class="kw">async fn </span>read_varint_async<VI: VarInt>(<span class="kw-2">&mut </span><span class="self">self</span>) -> <span class="prelude-ty">Result</span><VI> { |
| <span class="kw">let </span><span class="kw-2">mut </span>buf = [<span class="number">0 </span><span class="kw">as </span>u8; <span class="number">1</span>]; |
| <span class="kw">let </span><span class="kw-2">mut </span>p = VarIntProcessor::default(); |
| |
| <span class="kw">while </span>!p.finished() { |
| <span class="kw">let </span>read = <span class="self">self</span>.read(<span class="kw-2">&mut </span>buf).<span class="kw">await</span><span class="question-mark">?</span>; |
| |
| <span class="comment">// EOF |
| </span><span class="kw">if </span>read == <span class="number">0 </span>&& p.i == <span class="number">0 </span>{ |
| <span class="kw">return </span><span class="prelude-val">Err</span>(io::Error::new(io::ErrorKind::UnexpectedEof, <span class="string">"Reached EOF"</span>)); |
| } |
| <span class="kw">if </span>read == <span class="number">0 </span>{ |
| <span class="kw">break</span>; |
| } |
| |
| p.push(buf[<span class="number">0</span>])<span class="question-mark">?</span>; |
| } |
| |
| <span class="prelude-val">Ok</span>(p.decode()) |
| } |
| } |
| |
| <span class="kw">impl</span><R: Read> VarIntReader <span class="kw">for </span>R { |
| <span class="kw">fn </span>read_varint<VI: VarInt>(<span class="kw-2">&mut </span><span class="self">self</span>) -> <span class="prelude-ty">Result</span><VI> { |
| <span class="kw">let </span><span class="kw-2">mut </span>buf = [<span class="number">0 </span><span class="kw">as </span>u8; <span class="number">1</span>]; |
| <span class="kw">let </span><span class="kw-2">mut </span>p = VarIntProcessor::default(); |
| |
| <span class="kw">while </span>!p.finished() { |
| <span class="kw">let </span>read = <span class="self">self</span>.read(<span class="kw-2">&mut </span>buf)<span class="question-mark">?</span>; |
| |
| <span class="comment">// EOF |
| </span><span class="kw">if </span>read == <span class="number">0 </span>&& p.i == <span class="number">0 </span>{ |
| <span class="kw">return </span><span class="prelude-val">Err</span>(io::Error::new(io::ErrorKind::UnexpectedEof, <span class="string">"Reached EOF"</span>)); |
| } |
| <span class="kw">if </span>read == <span class="number">0 </span>{ |
| <span class="kw">break</span>; |
| } |
| |
| p.push(buf[<span class="number">0</span>])<span class="question-mark">?</span>; |
| } |
| |
| <span class="prelude-val">Ok</span>(p.decode()) |
| } |
| } |
| |
| <span class="doccomment">/// A trait for reading FixedInts from any other `Reader`. |
| </span><span class="kw">pub trait </span>FixedIntReader { |
| <span class="doccomment">/// Read a fixed integer from a reader. How many bytes are read depends on `FI`. |
| /// |
| /// On EOF, an io::Error with io::ErrorKind::UnexpectedEof is returned. |
| </span><span class="kw">fn </span>read_fixedint<FI: FixedInt>(<span class="kw-2">&mut </span><span class="self">self</span>) -> <span class="prelude-ty">Result</span><FI>; |
| } |
| |
| <span class="doccomment">/// Like FixedIntReader, but returns a future. |
| </span><span class="attribute">#[cfg(any(feature = <span class="string">"tokio_async"</span>, feature = <span class="string">"futures_async"</span>))] |
| #[async_trait::async_trait] |
| </span><span class="kw">pub trait </span>FixedIntAsyncReader { |
| <span class="kw">async fn </span>read_fixedint_async<FI: FixedInt>(<span class="kw-2">&mut </span><span class="self">self</span>) -> <span class="prelude-ty">Result</span><FI>; |
| } |
| |
| <span class="attribute">#[cfg(any(feature = <span class="string">"tokio_async"</span>, feature = <span class="string">"futures_async"</span>))] |
| #[async_trait::async_trait] |
| </span><span class="kw">impl</span><AR: AsyncRead + Unpin + Send> FixedIntAsyncReader <span class="kw">for </span>AR { |
| <span class="kw">async fn </span>read_fixedint_async<FI: FixedInt>(<span class="kw-2">&mut </span><span class="self">self</span>) -> <span class="prelude-ty">Result</span><FI> { |
| <span class="kw">let </span><span class="kw-2">mut </span>buf = [<span class="number">0 </span><span class="kw">as </span>u8; <span class="number">8</span>]; |
| <span class="self">self</span>.read_exact(<span class="kw-2">&mut </span>buf[<span class="number">0</span>..FI::required_space()]).<span class="kw">await</span><span class="question-mark">?</span>; |
| <span class="prelude-val">Ok</span>(FI::decode_fixed(<span class="kw-2">&</span>buf[<span class="number">0</span>..FI::required_space()])) |
| } |
| } |
| |
| <span class="kw">impl</span><R: Read> FixedIntReader <span class="kw">for </span>R { |
| <span class="kw">fn </span>read_fixedint<FI: FixedInt>(<span class="kw-2">&mut </span><span class="self">self</span>) -> <span class="prelude-ty">Result</span><FI> { |
| <span class="kw">let </span><span class="kw-2">mut </span>buf = [<span class="number">0 </span><span class="kw">as </span>u8; <span class="number">8</span>]; |
| <span class="self">self</span>.read_exact(<span class="kw-2">&mut </span>buf[<span class="number">0</span>..FI::required_space()])<span class="question-mark">?</span>; |
| <span class="prelude-val">Ok</span>(FI::decode_fixed(<span class="kw-2">&</span>buf[<span class="number">0</span>..FI::required_space()])) |
| } |
| } |
| </code></pre></div> |
| </section></div></main><div id="rustdoc-vars" data-root-path="../../" data-current-crate="integer_encoding" data-themes="ayu,dark,light" data-resource-suffix="" data-rustdoc-version="1.66.0-nightly (5c8bff74b 2022-10-21)" ></div></body></html> |