| <!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/httparse-1.8.0/src/simd/sse42.rs`."><meta name="keywords" content="rust, rustlang, rust-lang"><title>sse42.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="../../../httparse/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="../../../httparse/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><span class="kw">crate</span>::iter::Bytes; |
| |
| <span class="kw">pub unsafe fn </span>parse_uri_batch_16(bytes: <span class="kw-2">&mut </span>Bytes) { |
| <span class="kw">while </span>bytes.as_ref().len() >= <span class="number">16 </span>{ |
| <span class="kw">let </span>advance = match_url_char_16_sse(bytes.as_ref()); |
| bytes.advance(advance); |
| |
| <span class="kw">if </span>advance != <span class="number">16 </span>{ |
| <span class="kw">break</span>; |
| } |
| } |
| } |
| |
| <span class="attribute">#[target_feature(enable = <span class="string">"sse4.2"</span>)] |
| #[allow(non_snake_case, overflowing_literals)] |
| </span><span class="kw">unsafe fn </span>match_url_char_16_sse(buf: <span class="kw-2">&</span>[u8]) -> usize { |
| <span class="macro">debug_assert!</span>(buf.len() >= <span class="number">16</span>); |
| |
| <span class="attribute">#[cfg(target_arch = <span class="string">"x86"</span>)] |
| </span><span class="kw">use </span>core::arch::x86::<span class="kw-2">*</span>; |
| <span class="attribute">#[cfg(target_arch = <span class="string">"x86_64"</span>)] |
| </span><span class="kw">use </span>core::arch::x86_64::<span class="kw-2">*</span>; |
| |
| <span class="kw">let </span>ptr = buf.as_ptr(); |
| |
| <span class="kw">let </span>LSH: __m128i = _mm_set1_epi8(<span class="number">0x0f</span>); |
| |
| <span class="comment">// The first 0xf8 corresponds to the 8 first rows of the first column |
| // of URI_MAP in the crate's root, with the first row corresponding to bit 0 |
| // and the 8th row corresponding to bit 7. |
| // The 8 first rows give 0 0 0 1 1 1 1 1, which is 0xf8 (with least |
| // significant digit on the left). |
| // |
| // Another example just to drive the point home: in column 15, '>' is |
| // rejected, so the values are 0 0 1 0 1 1 1 1, which gives us 0xf4. |
| // |
| // Thanks to Vlad Krasnov for explaining this stuff to us mere mortals in |
| // a GitHub comment! |
| // |
| // https://github.com/seanmonstar/httparse/pull/89#issuecomment-807039219 |
| |
| </span><span class="kw">let </span>URI: __m128i = _mm_setr_epi8( |
| <span class="number">0xf8</span>, <span class="number">0xfc</span>, <span class="number">0xfc</span>, <span class="number">0xfc</span>, <span class="number">0xfc</span>, <span class="number">0xfc</span>, <span class="number">0xfc</span>, <span class="number">0xfc</span>, |
| <span class="number">0xfc</span>, <span class="number">0xfc</span>, <span class="number">0xfc</span>, <span class="number">0xfc</span>, <span class="number">0xf4</span>, <span class="number">0xfc</span>, <span class="number">0xf4</span>, <span class="number">0x7c</span>, |
| ); |
| <span class="kw">let </span>ARF: __m128i = _mm_setr_epi8( |
| <span class="number">0x01</span>, <span class="number">0x02</span>, <span class="number">0x04</span>, <span class="number">0x08</span>, <span class="number">0x10</span>, <span class="number">0x20</span>, <span class="number">0x40</span>, <span class="number">0x80</span>, |
| <span class="number">0x00</span>, <span class="number">0x00</span>, <span class="number">0x00</span>, <span class="number">0x00</span>, <span class="number">0x00</span>, <span class="number">0x00</span>, <span class="number">0x00</span>, <span class="number">0x00</span>, |
| ); |
| |
| <span class="kw">let </span>data = _mm_lddqu_si128(ptr <span class="kw">as </span><span class="kw-2">*const </span><span class="kw">_</span>); |
| <span class="kw">let </span>rbms = _mm_shuffle_epi8(URI, data); |
| <span class="kw">let </span>cols = _mm_and_si128(LSH, _mm_srli_epi16(data, <span class="number">4</span>)); |
| <span class="kw">let </span>bits = _mm_and_si128(_mm_shuffle_epi8(ARF, cols), rbms); |
| |
| <span class="kw">let </span>v = _mm_cmpeq_epi8(bits, _mm_setzero_si128()); |
| <span class="kw">let </span>r = <span class="number">0xffff_0000 </span>| _mm_movemask_epi8(v) <span class="kw">as </span>u32; |
| |
| _tzcnt_u32(r) <span class="kw">as </span>usize |
| } |
| |
| <span class="kw">pub unsafe fn </span>match_header_value_batch_16(bytes: <span class="kw-2">&mut </span>Bytes) { |
| <span class="kw">while </span>bytes.as_ref().len() >= <span class="number">16 </span>{ |
| <span class="kw">let </span>advance = match_header_value_char_16_sse(bytes.as_ref()); |
| bytes.advance(advance); |
| |
| <span class="kw">if </span>advance != <span class="number">16 </span>{ |
| <span class="kw">break</span>; |
| } |
| } |
| } |
| |
| <span class="attribute">#[target_feature(enable = <span class="string">"sse4.2"</span>)] |
| #[allow(non_snake_case)] |
| </span><span class="kw">unsafe fn </span>match_header_value_char_16_sse(buf: <span class="kw-2">&</span>[u8]) -> usize { |
| <span class="macro">debug_assert!</span>(buf.len() >= <span class="number">16</span>); |
| |
| <span class="attribute">#[cfg(target_arch = <span class="string">"x86"</span>)] |
| </span><span class="kw">use </span>core::arch::x86::<span class="kw-2">*</span>; |
| <span class="attribute">#[cfg(target_arch = <span class="string">"x86_64"</span>)] |
| </span><span class="kw">use </span>core::arch::x86_64::<span class="kw-2">*</span>; |
| |
| <span class="kw">let </span>ptr = buf.as_ptr(); |
| |
| <span class="comment">// %x09 %x20-%x7e %x80-%xff |
| </span><span class="kw">let </span>TAB: __m128i = _mm_set1_epi8(<span class="number">0x09</span>); |
| <span class="kw">let </span>DEL: __m128i = _mm_set1_epi8(<span class="number">0x7f</span>); |
| <span class="kw">let </span>LOW: __m128i = _mm_set1_epi8(<span class="number">0x20</span>); |
| |
| <span class="kw">let </span>dat = _mm_lddqu_si128(ptr <span class="kw">as </span><span class="kw-2">*const </span><span class="kw">_</span>); |
| <span class="comment">// unsigned comparison dat >= LOW |
| </span><span class="kw">let </span>low = _mm_cmpeq_epi8(_mm_max_epu8(dat, LOW), dat); |
| <span class="kw">let </span>tab = _mm_cmpeq_epi8(dat, TAB); |
| <span class="kw">let </span>del = _mm_cmpeq_epi8(dat, DEL); |
| <span class="kw">let </span>bit = _mm_andnot_si128(del, _mm_or_si128(low, tab)); |
| <span class="kw">let </span>rev = _mm_cmpeq_epi8(bit, _mm_setzero_si128()); |
| <span class="kw">let </span>res = <span class="number">0xffff_0000 </span>| _mm_movemask_epi8(rev) <span class="kw">as </span>u32; |
| |
| _tzcnt_u32(res) <span class="kw">as </span>usize |
| } |
| |
| <span class="attribute">#[test] |
| </span><span class="kw">fn </span>sse_code_matches_uri_chars_table() { |
| <span class="kw">match </span><span class="kw">super</span>::detect() { |
| <span class="kw">super</span>::SSE_42 | <span class="kw">super</span>::AVX_2_AND_SSE_42 => {}, |
| <span class="kw">_ </span>=> <span class="kw">return</span>, |
| } |
| |
| <span class="kw">unsafe </span>{ |
| <span class="macro">assert!</span>(byte_is_allowed(<span class="string">b'_'</span>, parse_uri_batch_16)); |
| |
| <span class="kw">for </span>(b, allowed) <span class="kw">in </span><span class="kw">crate</span>::URI_MAP.iter().cloned().enumerate() { |
| <span class="macro">assert_eq!</span>( |
| byte_is_allowed(b <span class="kw">as </span>u8, parse_uri_batch_16), allowed, |
| <span class="string">"byte_is_allowed({:?}) should be {:?}"</span>, b, allowed, |
| ); |
| } |
| } |
| } |
| |
| <span class="attribute">#[test] |
| </span><span class="kw">fn </span>sse_code_matches_header_value_chars_table() { |
| <span class="kw">match </span><span class="kw">super</span>::detect() { |
| <span class="kw">super</span>::SSE_42 | <span class="kw">super</span>::AVX_2_AND_SSE_42 => {}, |
| <span class="kw">_ </span>=> <span class="kw">return</span>, |
| } |
| |
| <span class="kw">unsafe </span>{ |
| <span class="macro">assert!</span>(byte_is_allowed(<span class="string">b'_'</span>, match_header_value_batch_16)); |
| |
| <span class="kw">for </span>(b, allowed) <span class="kw">in </span><span class="kw">crate</span>::HEADER_VALUE_MAP.iter().cloned().enumerate() { |
| <span class="macro">assert_eq!</span>( |
| byte_is_allowed(b <span class="kw">as </span>u8, match_header_value_batch_16), allowed, |
| <span class="string">"byte_is_allowed({:?}) should be {:?}"</span>, b, allowed, |
| ); |
| } |
| } |
| } |
| |
| <span class="attribute">#[cfg(test)] |
| </span><span class="kw">unsafe fn </span>byte_is_allowed(byte: u8, f: <span class="kw">unsafe fn</span>(bytes: <span class="kw-2">&mut </span>Bytes<<span class="lifetime">'_</span>>)) -> bool { |
| <span class="kw">let </span>slice = [ |
| <span class="string">b'_'</span>, <span class="string">b'_'</span>, <span class="string">b'_'</span>, <span class="string">b'_'</span>, |
| <span class="string">b'_'</span>, <span class="string">b'_'</span>, <span class="string">b'_'</span>, <span class="string">b'_'</span>, |
| <span class="string">b'_'</span>, <span class="string">b'_'</span>, byte, <span class="string">b'_'</span>, |
| <span class="string">b'_'</span>, <span class="string">b'_'</span>, <span class="string">b'_'</span>, <span class="string">b'_'</span>, |
| ]; |
| <span class="kw">let </span><span class="kw-2">mut </span>bytes = Bytes::new(<span class="kw-2">&</span>slice); |
| |
| f(<span class="kw-2">&mut </span>bytes); |
| |
| <span class="kw">match </span>bytes.pos() { |
| <span class="number">16 </span>=> <span class="bool-val">true</span>, |
| <span class="number">10 </span>=> <span class="bool-val">false</span>, |
| <span class="kw">_ </span>=> <span class="macro">unreachable!</span>(), |
| } |
| } |
| </code></pre></div> |
| </section></div></main><div id="rustdoc-vars" data-root-path="../../../" data-current-crate="httparse" data-themes="ayu,dark,light" data-resource-suffix="" data-rustdoc-version="1.66.0-nightly (5c8bff74b 2022-10-21)" ></div></body></html> |
