| <!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 `quiche/src/h3/qpack/huffman/mod.rs`."><title>mod.rs - source</title><script>if(window.location.protocol!=="file:")document.head.insertAdjacentHTML("beforeend","SourceSerif4-Regular-46f98efaafac5295.ttf.woff2,FiraSans-Regular-018c141bf0843ffd.woff2,FiraSans-Medium-8f9a781e4970d388.woff2,SourceCodePro-Regular-562dcc5011b6de7d.ttf.woff2,SourceCodePro-Semibold-d899c5a5c4aeb14a.ttf.woff2".split(",").map(f=>`<link rel="preload" as="font" type="font/woff2" crossorigin href="../../../../../static.files/${f}">`).join(""))</script><link rel="stylesheet" href="../../../../../static.files/normalize-76eba96aa4d2e634.css"><link rel="stylesheet" href="../../../../../static.files/rustdoc-2c208a72533b4dd0.css"><meta name="rustdoc-vars" data-root-path="../../../../../" data-static-root-path="../../../../../static.files/" data-current-crate="quiche" data-themes="" data-resource-suffix="" data-rustdoc-version="1.79.0-nightly (0d8b3346a 2024-04-14)" data-channel="nightly" data-search-js="search-ffac13a0df2b1870.js" data-settings-js="settings-4313503d2e1961c2.js" ><script src="../../../../../static.files/storage-e32f0c247825364d.js"></script><script defer src="../../../../../static.files/src-script-e66d777a5a92e9b2.js"></script><script defer src="../../../../../src-files.js"></script><script defer src="../../../../../static.files/main-c97aec732c613ca4.js"></script><noscript><link rel="stylesheet" href="../../../../../static.files/noscript-09095024cf37855e.css"></noscript><link rel="alternate icon" type="image/png" href="../../../../../static.files/favicon-32x32-422f7d1d52889060.png"><link rel="icon" type="image/svg+xml" href="../../../../../static.files/favicon-2c020d218678b618.svg"></head><body class="rustdoc src"><!--[if lte IE 11]><div class="warning">This old browser is unsupported and will most likely display funky things.</div><![endif]--><nav class="sidebar"><div class="src-sidebar-title"><h2>Files</h2></div></nav><div class="sidebar-resizer"></div><main><nav class="sub"><form class="search-form"><span></span><div id="sidebar-button" tabindex="-1"><a href="../../../../../quiche/all.html" title="show sidebar"></a></div><input class="search-input" name="search" aria-label="Run search in the documentation" autocomplete="off" spellcheck="false" placeholder="Click or press ‘S’ to search, ‘?’ for more options…" type="search"><div id="help-button" tabindex="-1"><a href="../../../../../help.html" title="help">?</a></div><div id="settings-menu" tabindex="-1"><a href="../../../../../settings.html" title="settings">Settings</a></div></form></nav><section id="main-content" class="content"><div class="example-wrap"><div data-nosnippet><pre class="src-line-numbers"><a href="#1" id="1">1</a> |
| <a href="#2" id="2">2</a> |
| <a href="#3" id="3">3</a> |
| <a href="#4" id="4">4</a> |
| <a href="#5" id="5">5</a> |
| <a href="#6" id="6">6</a> |
| <a href="#7" id="7">7</a> |
| <a href="#8" id="8">8</a> |
| <a href="#9" id="9">9</a> |
| <a href="#10" id="10">10</a> |
| <a href="#11" id="11">11</a> |
| <a href="#12" id="12">12</a> |
| <a href="#13" id="13">13</a> |
| <a href="#14" id="14">14</a> |
| <a href="#15" id="15">15</a> |
| <a href="#16" id="16">16</a> |
| <a href="#17" id="17">17</a> |
| <a href="#18" id="18">18</a> |
| <a href="#19" id="19">19</a> |
| <a href="#20" id="20">20</a> |
| <a href="#21" id="21">21</a> |
| <a href="#22" id="22">22</a> |
| <a href="#23" id="23">23</a> |
| <a href="#24" id="24">24</a> |
| <a href="#25" id="25">25</a> |
| <a href="#26" id="26">26</a> |
| <a href="#27" id="27">27</a> |
| <a href="#28" id="28">28</a> |
| <a href="#29" id="29">29</a> |
| <a href="#30" id="30">30</a> |
| <a href="#31" id="31">31</a> |
| <a href="#32" id="32">32</a> |
| <a href="#33" id="33">33</a> |
| <a href="#34" id="34">34</a> |
| <a href="#35" id="35">35</a> |
| <a href="#36" id="36">36</a> |
| <a href="#37" id="37">37</a> |
| <a href="#38" id="38">38</a> |
| <a href="#39" id="39">39</a> |
| <a href="#40" id="40">40</a> |
| <a href="#41" id="41">41</a> |
| <a href="#42" id="42">42</a> |
| <a href="#43" id="43">43</a> |
| <a href="#44" id="44">44</a> |
| <a href="#45" id="45">45</a> |
| <a href="#46" id="46">46</a> |
| <a href="#47" id="47">47</a> |
| <a href="#48" id="48">48</a> |
| <a href="#49" id="49">49</a> |
| <a href="#50" id="50">50</a> |
| <a href="#51" id="51">51</a> |
| <a href="#52" id="52">52</a> |
| <a href="#53" id="53">53</a> |
| <a href="#54" id="54">54</a> |
| <a href="#55" id="55">55</a> |
| <a href="#56" id="56">56</a> |
| <a href="#57" id="57">57</a> |
| <a href="#58" id="58">58</a> |
| <a href="#59" id="59">59</a> |
| <a href="#60" id="60">60</a> |
| <a href="#61" id="61">61</a> |
| <a href="#62" id="62">62</a> |
| <a href="#63" id="63">63</a> |
| <a href="#64" id="64">64</a> |
| <a href="#65" id="65">65</a> |
| <a href="#66" id="66">66</a> |
| <a href="#67" id="67">67</a> |
| <a href="#68" id="68">68</a> |
| <a href="#69" id="69">69</a> |
| <a href="#70" id="70">70</a> |
| <a href="#71" id="71">71</a> |
| <a href="#72" id="72">72</a> |
| <a href="#73" id="73">73</a> |
| <a href="#74" id="74">74</a> |
| <a href="#75" id="75">75</a> |
| <a href="#76" id="76">76</a> |
| <a href="#77" id="77">77</a> |
| <a href="#78" id="78">78</a> |
| <a href="#79" id="79">79</a> |
| <a href="#80" id="80">80</a> |
| <a href="#81" id="81">81</a> |
| <a href="#82" id="82">82</a> |
| <a href="#83" id="83">83</a> |
| <a href="#84" id="84">84</a> |
| <a href="#85" id="85">85</a> |
| <a href="#86" id="86">86</a> |
| <a href="#87" id="87">87</a> |
| <a href="#88" id="88">88</a> |
| <a href="#89" id="89">89</a> |
| <a href="#90" id="90">90</a> |
| <a href="#91" id="91">91</a> |
| <a href="#92" id="92">92</a> |
| <a href="#93" id="93">93</a> |
| <a href="#94" id="94">94</a> |
| <a href="#95" id="95">95</a> |
| <a href="#96" id="96">96</a> |
| <a href="#97" id="97">97</a> |
| <a href="#98" id="98">98</a> |
| <a href="#99" id="99">99</a> |
| <a href="#100" id="100">100</a> |
| <a href="#101" id="101">101</a> |
| <a href="#102" id="102">102</a> |
| <a href="#103" id="103">103</a> |
| <a href="#104" id="104">104</a> |
| <a href="#105" id="105">105</a> |
| <a href="#106" id="106">106</a> |
| <a href="#107" id="107">107</a> |
| <a href="#108" id="108">108</a> |
| <a href="#109" id="109">109</a> |
| <a href="#110" id="110">110</a> |
| <a href="#111" id="111">111</a> |
| <a href="#112" id="112">112</a> |
| <a href="#113" id="113">113</a> |
| <a href="#114" id="114">114</a> |
| <a href="#115" id="115">115</a> |
| <a href="#116" id="116">116</a> |
| <a href="#117" id="117">117</a> |
| <a href="#118" id="118">118</a> |
| <a href="#119" id="119">119</a> |
| <a href="#120" id="120">120</a> |
| <a href="#121" id="121">121</a> |
| <a href="#122" id="122">122</a> |
| <a href="#123" id="123">123</a> |
| <a href="#124" id="124">124</a> |
| <a href="#125" id="125">125</a> |
| <a href="#126" id="126">126</a> |
| <a href="#127" id="127">127</a> |
| <a href="#128" id="128">128</a> |
| <a href="#129" id="129">129</a> |
| <a href="#130" id="130">130</a> |
| <a href="#131" id="131">131</a> |
| <a href="#132" id="132">132</a> |
| <a href="#133" id="133">133</a> |
| <a href="#134" id="134">134</a> |
| <a href="#135" id="135">135</a> |
| <a href="#136" id="136">136</a> |
| <a href="#137" id="137">137</a> |
| <a href="#138" id="138">138</a> |
| <a href="#139" id="139">139</a> |
| <a href="#140" id="140">140</a> |
| <a href="#141" id="141">141</a> |
| <a href="#142" id="142">142</a> |
| <a href="#143" id="143">143</a> |
| <a href="#144" id="144">144</a> |
| <a href="#145" id="145">145</a> |
| <a href="#146" id="146">146</a> |
| <a href="#147" id="147">147</a> |
| <a href="#148" id="148">148</a> |
| <a href="#149" id="149">149</a> |
| <a href="#150" id="150">150</a> |
| <a href="#151" id="151">151</a> |
| <a href="#152" id="152">152</a> |
| <a href="#153" id="153">153</a> |
| <a href="#154" id="154">154</a> |
| <a href="#155" id="155">155</a> |
| <a href="#156" id="156">156</a> |
| <a href="#157" id="157">157</a> |
| <a href="#158" id="158">158</a> |
| <a href="#159" id="159">159</a> |
| <a href="#160" id="160">160</a> |
| <a href="#161" id="161">161</a> |
| <a href="#162" id="162">162</a> |
| <a href="#163" id="163">163</a> |
| <a href="#164" id="164">164</a> |
| <a href="#165" id="165">165</a> |
| <a href="#166" id="166">166</a> |
| <a href="#167" id="167">167</a> |
| <a href="#168" id="168">168</a> |
| <a href="#169" id="169">169</a> |
| <a href="#170" id="170">170</a> |
| <a href="#171" id="171">171</a> |
| <a href="#172" id="172">172</a> |
| <a href="#173" id="173">173</a> |
| <a href="#174" id="174">174</a> |
| <a href="#175" id="175">175</a> |
| <a href="#176" id="176">176</a> |
| <a href="#177" id="177">177</a> |
| <a href="#178" id="178">178</a> |
| <a href="#179" id="179">179</a> |
| <a href="#180" id="180">180</a> |
| <a href="#181" id="181">181</a> |
| <a href="#182" id="182">182</a> |
| <a href="#183" id="183">183</a> |
| <a href="#184" id="184">184</a> |
| <a href="#185" id="185">185</a> |
| </pre></div><pre class="rust"><code><span class="comment">// Copyright (C) 2019, Cloudflare, Inc. |
| // All rights reserved. |
| // |
| // Redistribution and use in source and binary forms, with or without |
| // modification, are permitted provided that the following conditions are |
| // met: |
| // |
| // * Redistributions of source code must retain the above copyright notice, |
| // this list of conditions and the following disclaimer. |
| // |
| // * Redistributions in binary form must reproduce the above copyright |
| // notice, this list of conditions and the following disclaimer in the |
| // documentation and/or other materials provided with the distribution. |
| // |
| // THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS |
| // IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, |
| // THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR |
| // PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR |
| // CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, |
| // EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, |
| // PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR |
| // PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF |
| // LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING |
| // NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS |
| // SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. |
| |
| </span><span class="kw">use </span><span class="kw">super</span>::Error; |
| <span class="kw">use </span><span class="kw">super</span>::Result; |
| |
| <span class="kw">use </span><span class="self">self</span>::table::DECODE_TABLE; |
| <span class="kw">use </span><span class="self">self</span>::table::ENCODE_TABLE; |
| |
| <span class="kw">pub fn </span>decode(b: <span class="kw-2">&mut </span>octets::Octets) -> <span class="prelude-ty">Result</span><Vec<u8>> { |
| <span class="comment">// Max compression ratio is >= 0.5 |
| </span><span class="kw">let </span><span class="kw-2">mut </span>out = Vec::with_capacity(b.len() << <span class="number">1</span>); |
| |
| <span class="kw">let </span><span class="kw-2">mut </span>decoder = Decoder::new(); |
| |
| <span class="kw">while </span>b.cap() > <span class="number">0 </span>{ |
| <span class="kw">let </span>byte = b.get_u8()<span class="question-mark">?</span>; |
| |
| <span class="kw">if let </span><span class="prelude-val">Some</span>(b) = decoder.decode4(byte >> <span class="number">4</span>)<span class="question-mark">? </span>{ |
| out.push(b); |
| } |
| |
| <span class="kw">if let </span><span class="prelude-val">Some</span>(b) = decoder.decode4(byte & <span class="number">0xf</span>)<span class="question-mark">? </span>{ |
| out.push(b); |
| } |
| } |
| |
| <span class="kw">if </span>!decoder.is_final() { |
| <span class="kw">return </span><span class="prelude-val">Err</span>(Error::InvalidHuffmanEncoding); |
| } |
| |
| <span class="prelude-val">Ok</span>(out) |
| } |
| |
| <span class="kw">pub fn </span>encode<<span class="kw">const </span>LOWER_CASE: bool>( |
| src: <span class="kw-2">&</span>[u8], out: <span class="kw-2">&mut </span>octets::OctetsMut, |
| ) -> <span class="prelude-ty">Result</span><()> { |
| <span class="kw">let </span><span class="kw-2">mut </span>bits: u64 = <span class="number">0</span>; |
| <span class="kw">let </span><span class="kw-2">mut </span>pending = <span class="number">0</span>; |
| |
| <span class="kw">for </span><span class="kw-2">&</span>b <span class="kw">in </span>src { |
| <span class="kw">let </span>b = <span class="kw">if </span>LOWER_CASE { |
| b.to_ascii_lowercase() |
| } <span class="kw">else </span>{ |
| b |
| }; |
| <span class="kw">let </span>(nbits, code) = ENCODE_TABLE[b <span class="kw">as </span>usize]; |
| |
| pending += nbits; |
| |
| <span class="kw">if </span>pending < <span class="number">64 </span>{ |
| <span class="comment">// Have room for the new token |
| </span>bits |= code << (<span class="number">64 </span>- pending); |
| <span class="kw">continue</span>; |
| } |
| |
| pending -= <span class="number">64</span>; |
| <span class="comment">// Take only the bits that fit |
| </span>bits |= code >> pending; |
| out.put_u64(bits)<span class="question-mark">?</span>; |
| |
| bits = <span class="kw">if </span>pending == <span class="number">0 </span>{ |
| <span class="number">0 |
| </span>} <span class="kw">else </span>{ |
| code << (<span class="number">64 </span>- pending) |
| }; |
| } |
| |
| <span class="kw">if </span>pending == <span class="number">0 </span>{ |
| <span class="kw">return </span><span class="prelude-val">Ok</span>(()); |
| } |
| |
| bits |= u64::MAX >> pending; |
| <span class="comment">// TODO: replace with `next_multiple_of(8)` when stable |
| </span>pending = (pending + <span class="number">7</span>) & !<span class="number">7</span>; <span class="comment">// Round up to a byte |
| </span>bits >>= <span class="number">64 </span>- pending; |
| |
| <span class="kw">if </span>pending >= <span class="number">32 </span>{ |
| pending -= <span class="number">32</span>; |
| out.put_u32((bits >> pending) <span class="kw">as </span>u32)<span class="question-mark">?</span>; |
| } |
| |
| <span class="kw">while </span>pending > <span class="number">0 </span>{ |
| pending -= <span class="number">8</span>; |
| out.put_u8((bits >> pending) <span class="kw">as </span>u8)<span class="question-mark">?</span>; |
| } |
| |
| <span class="prelude-val">Ok</span>(()) |
| } |
| |
| <span class="kw">pub fn </span>encode_output_length<<span class="kw">const </span>LOWER_CASE: bool>(src: <span class="kw-2">&</span>[u8]) -> <span class="prelude-ty">Result</span><usize> { |
| <span class="kw">let </span><span class="kw-2">mut </span>bits: usize = <span class="number">0</span>; |
| |
| <span class="kw">for </span><span class="kw-2">&</span>b <span class="kw">in </span>src { |
| <span class="kw">let </span>b = <span class="kw">if </span>LOWER_CASE { |
| b.to_ascii_lowercase() |
| } <span class="kw">else </span>{ |
| b |
| }; |
| |
| <span class="kw">let </span>(nbits, <span class="kw">_</span>) = ENCODE_TABLE[b <span class="kw">as </span>usize]; |
| bits += nbits; |
| } |
| |
| <span class="kw">let </span><span class="kw-2">mut </span>len = bits / <span class="number">8</span>; |
| |
| <span class="kw">if </span>bits & <span class="number">7 </span>!= <span class="number">0 </span>{ |
| len += <span class="number">1</span>; |
| } |
| |
| <span class="kw">if </span>len > src.len() { |
| <span class="kw">return </span><span class="prelude-val">Err</span>(Error::InflatedHuffmanEncoding); |
| } |
| |
| <span class="prelude-val">Ok</span>(len) |
| } |
| |
| <span class="kw">struct </span>Decoder { |
| state: usize, |
| maybe_eos: bool, |
| } |
| |
| <span class="kw">impl </span>Decoder { |
| <span class="kw">fn </span>new() -> Decoder { |
| Decoder { |
| state: <span class="number">0</span>, |
| maybe_eos: <span class="bool-val">false</span>, |
| } |
| } |
| |
| <span class="comment">// Decodes 4 bits |
| </span><span class="kw">fn </span>decode4(<span class="kw-2">&mut </span><span class="self">self</span>, input: u8) -> <span class="prelude-ty">Result</span><<span class="prelude-ty">Option</span><u8>> { |
| <span class="kw">const </span>MAYBE_EOS: u8 = <span class="number">1</span>; |
| <span class="kw">const </span>DECODED: u8 = <span class="number">2</span>; |
| <span class="kw">const </span>ERROR: u8 = <span class="number">4</span>; |
| |
| <span class="comment">// (next-state, byte, flags) |
| </span><span class="kw">let </span>(next, byte, flags) = DECODE_TABLE[<span class="self">self</span>.state][input <span class="kw">as </span>usize]; |
| |
| <span class="kw">if </span>flags & ERROR == ERROR { |
| <span class="comment">// Data followed the EOS marker |
| </span><span class="kw">return </span><span class="prelude-val">Err</span>(Error::InvalidHuffmanEncoding); |
| } |
| |
| <span class="kw">let </span>ret = <span class="kw">if </span>flags & DECODED == DECODED { |
| <span class="prelude-val">Some</span>(byte) |
| } <span class="kw">else </span>{ |
| <span class="prelude-val">None |
| </span>}; |
| |
| <span class="self">self</span>.state = next; |
| <span class="self">self</span>.maybe_eos = flags & MAYBE_EOS == MAYBE_EOS; |
| |
| <span class="prelude-val">Ok</span>(ret) |
| } |
| |
| <span class="kw">fn </span>is_final(<span class="kw-2">&</span><span class="self">self</span>) -> bool { |
| <span class="self">self</span>.state == <span class="number">0 </span>|| <span class="self">self</span>.maybe_eos |
| } |
| } |
| |
| <span class="kw">mod </span>table; |
| </code></pre></div></section></main></body></html> |
