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<!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 to the Rust file `/home/mrh/.cargo/registry/src/github.com-1ecc6299db9ec823/adler32-1.0.3/src/lib.rs`."><meta name="keywords" content="rust, rustlang, rust-lang"><title>lib.rs.html -- source</title><link rel="stylesheet" type="text/css" href="../../normalize.css"><link rel="stylesheet" type="text/css" href="../../rustdoc.css" id="mainThemeStyle"><link rel="stylesheet" type="text/css" href="../../dark.css"><link rel="stylesheet" type="text/css" href="../../light.css" id="themeStyle"><script src="../../storage.js"></script><noscript><link rel="stylesheet" href="../../noscript.css"></noscript><link rel="shortcut icon" href="../../favicon.ico"><style type="text/css">#crate-search{background-image:url("../../down-arrow.svg");}</style></head><body class="rustdoc source"><!--[if lte IE 8]><div class="warning">This old browser is unsupported and will most likely display funky things.</div><![endif]--><nav class="sidebar"><div class="sidebar-menu">&#9776;</div><a href='../../adler32/index.html'><div class='logo-container'><img src='../../rust-logo.png' alt='logo'></div></a></nav><div class="theme-picker"><button id="theme-picker" aria-label="Pick another theme!"><img src="../../brush.svg" width="18" alt="Pick another theme!"></button><div id="theme-choices"></div></div><script src="../../theme.js"></script><nav class="sub"><form class="search-form js-only"><div class="search-container"><div><select id="crate-search"><option value="All crates">All crates</option></select><input class="search-input" name="search" autocomplete="off" spellcheck="false" placeholder="Click or press ‘S’ to search, ‘?’ for more options…" type="search"></div><a id="settings-menu" href="../../settings.html"><img src="../../wheel.svg" width="18" alt="Change settings"></a></div></form></nav><section id="main" class="content"><pre class="line-numbers"><span id="1"> 1</span>
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</pre><div class="example-wrap"><pre class="rust ">
<span class="doccomment">//! A minimal implementation of Adler32 for Rust.</span>
<span class="doccomment">//!</span>
<span class="doccomment">//! This provides the simple method adler32(), that exhausts a Read and</span>
<span class="doccomment">//! computes the Adler32 hash, as well as the RollingAdler32 struct, that can</span>
<span class="doccomment">//! build a hash byte-by-byte, allowing to &#39;forget&#39; past bytes in a rolling</span>
<span class="doccomment">//! fashion.</span>
<span class="doccomment">//!</span>
<span class="doccomment">//! The adler32 code has been translated (as accurately as I could manage) from</span>
<span class="doccomment">//! the zlib implementation.</span>
<span class="attribute">#[<span class="ident">cfg</span>(<span class="ident">test</span>)]</span>
<span class="kw">extern</span> <span class="kw">crate</span> <span class="ident">rand</span>;
<span class="kw">use</span> <span class="ident">std</span>::<span class="ident">io</span>;
<span class="comment">// adler32 algorithm and implementation taken from zlib; http://www.zlib.net/</span>
<span class="comment">// It was translated into Rust as accurately as I could manage</span>
<span class="comment">// The (slow) reference was taken from Wikipedia; https://en.wikipedia.org/</span>
<span class="comment">/* zlib.h -- interface of the &#39;zlib&#39; general purpose compression library
version 1.2.8, April 28th, 2013
Copyright (C) 1995-2013 Jean-loup Gailly and Mark Adler
This software is provided &#39;as-is&#39;, without any express or implied
warranty. In no event will the authors be held liable for any damages
arising from the use of this software.
Permission is granted to anyone to use this software for any purpose,
including commercial applications, and to alter it and redistribute it
freely, subject to the following restrictions:
1. The origin of this software must not be misrepresented; you must not
claim that you wrote the original software. If you use this software
in a product, an acknowledgment in the product documentation would be
appreciated but is not required.
2. Altered source versions must be plainly marked as such, and must not be
misrepresented as being the original software.
3. This notice may not be removed or altered from any source distribution.
Jean-loup Gailly Mark Adler
jloup@gzip.org madler@alumni.caltech.edu
*/</span>
<span class="comment">// largest prime smaller than 65536</span>
<span class="kw">const</span> <span class="ident">BASE</span>: <span class="ident">u32</span> <span class="op">=</span> <span class="number">65521</span>;
<span class="comment">// NMAX is the largest n such that 255n(n+1)/2 + (n+1)(BASE-1) &lt;= 2^32-1</span>
<span class="kw">const</span> <span class="ident">NMAX</span>: <span class="ident">usize</span> <span class="op">=</span> <span class="number">5552</span>;
<span class="attribute">#[<span class="ident">inline</span>(<span class="ident">always</span>)]</span>
<span class="kw">fn</span> <span class="ident">do1</span>(<span class="ident">adler</span>: <span class="kw-2">&amp;</span><span class="kw-2">mut</span> <span class="ident">u32</span>, <span class="ident">sum2</span>: <span class="kw-2">&amp;</span><span class="kw-2">mut</span> <span class="ident">u32</span>, <span class="ident">buf</span>: <span class="kw-2">&amp;</span>[<span class="ident">u8</span>]) {
<span class="kw-2">*</span><span class="ident">adler</span> <span class="op">+</span><span class="op">=</span> <span class="ident">buf</span>[<span class="number">0</span>] <span class="kw">as</span> <span class="ident">u32</span>;
<span class="kw-2">*</span><span class="ident">sum2</span> <span class="op">+</span><span class="op">=</span> <span class="kw-2">*</span><span class="ident">adler</span>;
}
<span class="attribute">#[<span class="ident">inline</span>(<span class="ident">always</span>)]</span>
<span class="kw">fn</span> <span class="ident">do2</span>(<span class="ident">adler</span>: <span class="kw-2">&amp;</span><span class="kw-2">mut</span> <span class="ident">u32</span>, <span class="ident">sum2</span>: <span class="kw-2">&amp;</span><span class="kw-2">mut</span> <span class="ident">u32</span>, <span class="ident">buf</span>: <span class="kw-2">&amp;</span>[<span class="ident">u8</span>]) {
<span class="ident">do1</span>(<span class="ident">adler</span>, <span class="ident">sum2</span>, <span class="kw-2">&amp;</span><span class="ident">buf</span>[<span class="number">0</span>..<span class="number">1</span>]);
<span class="ident">do1</span>(<span class="ident">adler</span>, <span class="ident">sum2</span>, <span class="kw-2">&amp;</span><span class="ident">buf</span>[<span class="number">1</span>..<span class="number">2</span>]);
}
<span class="attribute">#[<span class="ident">inline</span>(<span class="ident">always</span>)]</span>
<span class="kw">fn</span> <span class="ident">do4</span>(<span class="ident">adler</span>: <span class="kw-2">&amp;</span><span class="kw-2">mut</span> <span class="ident">u32</span>, <span class="ident">sum2</span>: <span class="kw-2">&amp;</span><span class="kw-2">mut</span> <span class="ident">u32</span>, <span class="ident">buf</span>: <span class="kw-2">&amp;</span>[<span class="ident">u8</span>]) {
<span class="ident">do2</span>(<span class="ident">adler</span>, <span class="ident">sum2</span>, <span class="kw-2">&amp;</span><span class="ident">buf</span>[<span class="number">0</span>..<span class="number">2</span>]);
<span class="ident">do2</span>(<span class="ident">adler</span>, <span class="ident">sum2</span>, <span class="kw-2">&amp;</span><span class="ident">buf</span>[<span class="number">2</span>..<span class="number">4</span>]);
}
<span class="attribute">#[<span class="ident">inline</span>(<span class="ident">always</span>)]</span>
<span class="kw">fn</span> <span class="ident">do8</span>(<span class="ident">adler</span>: <span class="kw-2">&amp;</span><span class="kw-2">mut</span> <span class="ident">u32</span>, <span class="ident">sum2</span>: <span class="kw-2">&amp;</span><span class="kw-2">mut</span> <span class="ident">u32</span>, <span class="ident">buf</span>: <span class="kw-2">&amp;</span>[<span class="ident">u8</span>]) {
<span class="ident">do4</span>(<span class="ident">adler</span>, <span class="ident">sum2</span>, <span class="kw-2">&amp;</span><span class="ident">buf</span>[<span class="number">0</span>..<span class="number">4</span>]);
<span class="ident">do4</span>(<span class="ident">adler</span>, <span class="ident">sum2</span>, <span class="kw-2">&amp;</span><span class="ident">buf</span>[<span class="number">4</span>..<span class="number">8</span>]);
}
<span class="attribute">#[<span class="ident">inline</span>(<span class="ident">always</span>)]</span>
<span class="kw">fn</span> <span class="ident">do16</span>(<span class="ident">adler</span>: <span class="kw-2">&amp;</span><span class="kw-2">mut</span> <span class="ident">u32</span>, <span class="ident">sum2</span>: <span class="kw-2">&amp;</span><span class="kw-2">mut</span> <span class="ident">u32</span>, <span class="ident">buf</span>: <span class="kw-2">&amp;</span>[<span class="ident">u8</span>]) {
<span class="ident">do8</span>(<span class="ident">adler</span>, <span class="ident">sum2</span>, <span class="kw-2">&amp;</span><span class="ident">buf</span>[<span class="number">0</span>..<span class="number">8</span>]);
<span class="ident">do8</span>(<span class="ident">adler</span>, <span class="ident">sum2</span>, <span class="kw-2">&amp;</span><span class="ident">buf</span>[<span class="number">8</span>..<span class="number">16</span>]);
}
<span class="doccomment">/// A rolling version of the Adler32 hash, which can &#39;forget&#39; past bytes.</span>
<span class="doccomment">///</span>
<span class="doccomment">/// Calling remove() will update the hash to the value it would have if that</span>
<span class="doccomment">/// past byte had never been fed to the algorithm. This allows you to get the</span>
<span class="doccomment">/// hash of a rolling window very efficiently.</span>
<span class="kw">pub</span> <span class="kw">struct</span> <span class="ident">RollingAdler32</span> {
<span class="ident">a</span>: <span class="ident">u32</span>,
<span class="ident">b</span>: <span class="ident">u32</span>,
}
<span class="kw">impl</span> <span class="ident">RollingAdler32</span> {
<span class="doccomment">/// Creates an empty Adler32 context (with hash 1).</span>
<span class="kw">pub</span> <span class="kw">fn</span> <span class="ident">new</span>() <span class="op">-</span><span class="op">&gt;</span> <span class="ident">RollingAdler32</span> {
<span class="self">Self</span>::<span class="ident">from_value</span>(<span class="number">1</span>)
}
<span class="doccomment">/// Creates an Adler32 context with the given initial value.</span>
<span class="kw">pub</span> <span class="kw">fn</span> <span class="ident">from_value</span>(<span class="ident">adler32</span>: <span class="ident">u32</span>) <span class="op">-</span><span class="op">&gt;</span> <span class="ident">RollingAdler32</span> {
<span class="kw">let</span> <span class="ident">a</span> <span class="op">=</span> <span class="ident">adler32</span> <span class="op">&amp;</span> <span class="number">0xFFFF</span>;
<span class="kw">let</span> <span class="ident">b</span> <span class="op">=</span> <span class="ident">adler32</span> <span class="op">&gt;</span><span class="op">&gt;</span> <span class="number">16</span>;
<span class="ident">RollingAdler32</span> { <span class="ident">a</span>: <span class="ident">a</span>, <span class="ident">b</span>: <span class="ident">b</span> }
}
<span class="doccomment">/// Convenience function initializing a context from the hash of a buffer.</span>
<span class="kw">pub</span> <span class="kw">fn</span> <span class="ident">from_buffer</span>(<span class="ident">buffer</span>: <span class="kw-2">&amp;</span>[<span class="ident">u8</span>]) <span class="op">-</span><span class="op">&gt;</span> <span class="ident">RollingAdler32</span> {
<span class="kw">let</span> <span class="kw-2">mut</span> <span class="ident">hash</span> <span class="op">=</span> <span class="ident">RollingAdler32</span>::<span class="ident">new</span>();
<span class="ident">hash</span>.<span class="ident">update_buffer</span>(<span class="ident">buffer</span>);
<span class="ident">hash</span>
}
<span class="doccomment">/// Returns the current hash.</span>
<span class="kw">pub</span> <span class="kw">fn</span> <span class="ident">hash</span>(<span class="kw-2">&amp;</span><span class="self">self</span>) <span class="op">-</span><span class="op">&gt;</span> <span class="ident">u32</span> {
(<span class="self">self</span>.<span class="ident">b</span> <span class="op">&lt;</span><span class="op">&lt;</span> <span class="number">16</span>) <span class="op">|</span> <span class="self">self</span>.<span class="ident">a</span>
}
<span class="doccomment">/// Removes the given `byte` that was fed to the algorithm `size` bytes ago.</span>
<span class="kw">pub</span> <span class="kw">fn</span> <span class="ident">remove</span>(<span class="kw-2">&amp;</span><span class="kw-2">mut</span> <span class="self">self</span>, <span class="ident">size</span>: <span class="ident">usize</span>, <span class="ident">byte</span>: <span class="ident">u8</span>) {
<span class="kw">let</span> <span class="ident">byte</span> <span class="op">=</span> <span class="ident">byte</span> <span class="kw">as</span> <span class="ident">u32</span>;
<span class="self">self</span>.<span class="ident">a</span> <span class="op">=</span> (<span class="self">self</span>.<span class="ident">a</span> <span class="op">+</span> <span class="ident">BASE</span> <span class="op">-</span> <span class="ident">byte</span>) <span class="op">%</span> <span class="ident">BASE</span>;
<span class="self">self</span>.<span class="ident">b</span> <span class="op">=</span> ((<span class="self">self</span>.<span class="ident">b</span> <span class="op">+</span> <span class="ident">BASE</span> <span class="op">-</span> <span class="number">1</span>)
.<span class="ident">wrapping_add</span>(<span class="ident">BASE</span>.<span class="ident">wrapping_sub</span>(<span class="ident">size</span> <span class="kw">as</span> <span class="ident">u32</span>)
.<span class="ident">wrapping_mul</span>(<span class="ident">byte</span>))) <span class="op">%</span> <span class="ident">BASE</span>;
}
<span class="doccomment">/// Feeds a new `byte` to the algorithm to update the hash.</span>
<span class="kw">pub</span> <span class="kw">fn</span> <span class="ident">update</span>(<span class="kw-2">&amp;</span><span class="kw-2">mut</span> <span class="self">self</span>, <span class="ident">byte</span>: <span class="ident">u8</span>) {
<span class="kw">let</span> <span class="ident">byte</span> <span class="op">=</span> <span class="ident">byte</span> <span class="kw">as</span> <span class="ident">u32</span>;
<span class="self">self</span>.<span class="ident">a</span> <span class="op">=</span> (<span class="self">self</span>.<span class="ident">a</span> <span class="op">+</span> <span class="ident">byte</span>) <span class="op">%</span> <span class="ident">BASE</span>;
<span class="self">self</span>.<span class="ident">b</span> <span class="op">=</span> (<span class="self">self</span>.<span class="ident">b</span> <span class="op">+</span> <span class="self">self</span>.<span class="ident">a</span>) <span class="op">%</span> <span class="ident">BASE</span>;
}
<span class="doccomment">/// Feeds a vector of bytes to the algorithm to update the hash.</span>
<span class="kw">pub</span> <span class="kw">fn</span> <span class="ident">update_buffer</span>(<span class="kw-2">&amp;</span><span class="kw-2">mut</span> <span class="self">self</span>, <span class="ident">buffer</span>: <span class="kw-2">&amp;</span>[<span class="ident">u8</span>]) {
<span class="kw">let</span> <span class="ident">len</span> <span class="op">=</span> <span class="ident">buffer</span>.<span class="ident">len</span>();
<span class="comment">// in case user likes doing a byte at a time, keep it fast</span>
<span class="kw">if</span> <span class="ident">len</span> <span class="op">=</span><span class="op">=</span> <span class="number">1</span> {
<span class="self">self</span>.<span class="ident">update</span>(<span class="ident">buffer</span>[<span class="number">0</span>]);
<span class="kw">return</span>;
}
<span class="comment">// in case short lengths are provided, keep it somewhat fast</span>
<span class="kw">if</span> <span class="ident">len</span> <span class="op">&lt;</span> <span class="number">16</span> {
<span class="kw">for</span> <span class="ident">pos</span> <span class="kw">in</span> <span class="number">0</span>..<span class="ident">len</span> {
<span class="self">self</span>.<span class="ident">a</span> <span class="op">+</span><span class="op">=</span> <span class="ident">buffer</span>[<span class="ident">pos</span>] <span class="kw">as</span> <span class="ident">u32</span>;
<span class="self">self</span>.<span class="ident">b</span> <span class="op">+</span><span class="op">=</span> <span class="self">self</span>.<span class="ident">a</span>;
}
<span class="kw">if</span> <span class="self">self</span>.<span class="ident">a</span> <span class="op">&gt;</span><span class="op">=</span> <span class="ident">BASE</span> {
<span class="self">self</span>.<span class="ident">a</span> <span class="op">-</span><span class="op">=</span> <span class="ident">BASE</span>;
}
<span class="self">self</span>.<span class="ident">b</span> <span class="op">%</span><span class="op">=</span> <span class="ident">BASE</span>;
<span class="kw">return</span>;
}
<span class="kw">let</span> <span class="kw-2">mut</span> <span class="ident">pos</span> <span class="op">=</span> <span class="number">0</span>;
<span class="comment">// do length NMAX blocks -- requires just one modulo operation;</span>
<span class="kw">while</span> <span class="ident">pos</span> <span class="op">+</span> <span class="ident">NMAX</span> <span class="op">&lt;</span><span class="op">=</span> <span class="ident">len</span> {
<span class="kw">let</span> <span class="ident">end</span> <span class="op">=</span> <span class="ident">pos</span> <span class="op">+</span> <span class="ident">NMAX</span>;
<span class="kw">while</span> <span class="ident">pos</span> <span class="op">&lt;</span> <span class="ident">end</span> {
<span class="comment">// 16 sums unrolled</span>
<span class="ident">do16</span>(<span class="kw-2">&amp;</span><span class="kw-2">mut</span> <span class="self">self</span>.<span class="ident">a</span>, <span class="kw-2">&amp;</span><span class="kw-2">mut</span> <span class="self">self</span>.<span class="ident">b</span>, <span class="kw-2">&amp;</span><span class="ident">buffer</span>[<span class="ident">pos</span>..<span class="ident">pos</span> <span class="op">+</span> <span class="number">16</span>]);
<span class="ident">pos</span> <span class="op">+</span><span class="op">=</span> <span class="number">16</span>;
}
<span class="self">self</span>.<span class="ident">a</span> <span class="op">%</span><span class="op">=</span> <span class="ident">BASE</span>;
<span class="self">self</span>.<span class="ident">b</span> <span class="op">%</span><span class="op">=</span> <span class="ident">BASE</span>;
}
<span class="comment">// do remaining bytes (less than NMAX, still just one modulo)</span>
<span class="kw">if</span> <span class="ident">pos</span> <span class="op">&lt;</span> <span class="ident">len</span> { <span class="comment">// avoid modulos if none remaining</span>
<span class="kw">while</span> <span class="ident">len</span> <span class="op">-</span> <span class="ident">pos</span> <span class="op">&gt;</span><span class="op">=</span> <span class="number">16</span> {
<span class="ident">do16</span>(<span class="kw-2">&amp;</span><span class="kw-2">mut</span> <span class="self">self</span>.<span class="ident">a</span>, <span class="kw-2">&amp;</span><span class="kw-2">mut</span> <span class="self">self</span>.<span class="ident">b</span>, <span class="kw-2">&amp;</span><span class="ident">buffer</span>[<span class="ident">pos</span>..<span class="ident">pos</span> <span class="op">+</span> <span class="number">16</span>]);
<span class="ident">pos</span> <span class="op">+</span><span class="op">=</span> <span class="number">16</span>;
}
<span class="kw">while</span> <span class="ident">len</span> <span class="op">-</span> <span class="ident">pos</span> <span class="op">&gt;</span> <span class="number">0</span> {
<span class="self">self</span>.<span class="ident">a</span> <span class="op">+</span><span class="op">=</span> <span class="ident">buffer</span>[<span class="ident">pos</span>] <span class="kw">as</span> <span class="ident">u32</span>;
<span class="self">self</span>.<span class="ident">b</span> <span class="op">+</span><span class="op">=</span> <span class="self">self</span>.<span class="ident">a</span>;
<span class="ident">pos</span> <span class="op">+</span><span class="op">=</span> <span class="number">1</span>;
}
<span class="self">self</span>.<span class="ident">a</span> <span class="op">%</span><span class="op">=</span> <span class="ident">BASE</span>;
<span class="self">self</span>.<span class="ident">b</span> <span class="op">%</span><span class="op">=</span> <span class="ident">BASE</span>;
}
}
}
<span class="doccomment">/// Consume a Read object and returns the Adler32 hash.</span>
<span class="kw">pub</span> <span class="kw">fn</span> <span class="ident">adler32</span><span class="op">&lt;</span><span class="ident">R</span>: <span class="ident">io</span>::<span class="ident">Read</span><span class="op">&gt;</span>(<span class="kw-2">mut</span> <span class="ident">reader</span>: <span class="ident">R</span>) <span class="op">-</span><span class="op">&gt;</span> <span class="ident">io</span>::<span class="prelude-ty">Result</span><span class="op">&lt;</span><span class="ident">u32</span><span class="op">&gt;</span> {
<span class="kw">let</span> <span class="kw-2">mut</span> <span class="ident">hash</span> <span class="op">=</span> <span class="ident">RollingAdler32</span>::<span class="ident">new</span>();
<span class="kw">let</span> <span class="kw-2">mut</span> <span class="ident">buffer</span> <span class="op">=</span> [<span class="number">0u8</span>; <span class="ident">NMAX</span>];
<span class="kw">let</span> <span class="kw-2">mut</span> <span class="ident">read</span> <span class="op">=</span> <span class="macro">try</span><span class="macro">!</span>(<span class="ident">reader</span>.<span class="ident">read</span>(<span class="kw-2">&amp;</span><span class="kw-2">mut</span> <span class="ident">buffer</span>));
<span class="kw">while</span> <span class="ident">read</span> <span class="op">&gt;</span> <span class="number">0</span> {
<span class="ident">hash</span>.<span class="ident">update_buffer</span>(<span class="kw-2">&amp;</span><span class="ident">buffer</span>[..<span class="ident">read</span>]);
<span class="ident">read</span> <span class="op">=</span> <span class="macro">try</span><span class="macro">!</span>(<span class="ident">reader</span>.<span class="ident">read</span>(<span class="kw-2">&amp;</span><span class="kw-2">mut</span> <span class="ident">buffer</span>));
}
<span class="prelude-val">Ok</span>(<span class="ident">hash</span>.<span class="ident">hash</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">rand</span>;
<span class="kw">use</span> <span class="ident">rand</span>::<span class="ident">Rng</span>;
<span class="kw">use</span> <span class="ident">std</span>::<span class="ident">io</span>;
<span class="kw">use</span> <span class="kw">super</span>::{<span class="ident">BASE</span>, <span class="ident">adler32</span>, <span class="ident">RollingAdler32</span>};
<span class="kw">fn</span> <span class="ident">adler32_slow</span><span class="op">&lt;</span><span class="ident">R</span>: <span class="ident">io</span>::<span class="ident">Read</span><span class="op">&gt;</span>(<span class="ident">reader</span>: <span class="ident">R</span>) <span class="op">-</span><span class="op">&gt;</span> <span class="ident">io</span>::<span class="prelude-ty">Result</span><span class="op">&lt;</span><span class="ident">u32</span><span class="op">&gt;</span> {
<span class="kw">let</span> <span class="kw-2">mut</span> <span class="ident">a</span>: <span class="ident">u32</span> <span class="op">=</span> <span class="number">1</span>;
<span class="kw">let</span> <span class="kw-2">mut</span> <span class="ident">b</span>: <span class="ident">u32</span> <span class="op">=</span> <span class="number">0</span>;
<span class="kw">for</span> <span class="ident">byte</span> <span class="kw">in</span> <span class="ident">reader</span>.<span class="ident">bytes</span>() {
<span class="kw">let</span> <span class="ident">byte</span> <span class="op">=</span> <span class="macro">try</span><span class="macro">!</span>(<span class="ident">byte</span>) <span class="kw">as</span> <span class="ident">u32</span>;
<span class="ident">a</span> <span class="op">=</span> (<span class="ident">a</span> <span class="op">+</span> <span class="ident">byte</span>) <span class="op">%</span> <span class="ident">BASE</span>;
<span class="ident">b</span> <span class="op">=</span> (<span class="ident">b</span> <span class="op">+</span> <span class="ident">a</span>) <span class="op">%</span> <span class="ident">BASE</span>;
}
<span class="prelude-val">Ok</span>((<span class="ident">b</span> <span class="op">&lt;</span><span class="op">&lt;</span> <span class="number">16</span>) <span class="op">|</span> <span class="ident">a</span>)
}
<span class="attribute">#[<span class="ident">test</span>]</span>
<span class="kw">fn</span> <span class="ident">testvectors</span>() {
<span class="kw">fn</span> <span class="ident">do_test</span>(<span class="ident">v</span>: <span class="ident">u32</span>, <span class="ident">bytes</span>: <span class="kw-2">&amp;</span>[<span class="ident">u8</span>]) {
<span class="kw">let</span> <span class="kw-2">mut</span> <span class="ident">hash</span> <span class="op">=</span> <span class="ident">RollingAdler32</span>::<span class="ident">new</span>();
<span class="ident">hash</span>.<span class="ident">update_buffer</span>(<span class="kw-2">&amp;</span><span class="ident">bytes</span>);
<span class="macro">assert_eq</span><span class="macro">!</span>(<span class="ident">hash</span>.<span class="ident">hash</span>(), <span class="ident">v</span>);
<span class="kw">let</span> <span class="ident">r</span> <span class="op">=</span> <span class="ident">io</span>::<span class="ident">Cursor</span>::<span class="ident">new</span>(<span class="ident">bytes</span>);
<span class="macro">assert_eq</span><span class="macro">!</span>(<span class="ident">adler32</span>(<span class="ident">r</span>).<span class="ident">unwrap</span>(), <span class="ident">v</span>);
}
<span class="ident">do_test</span>(<span class="number">0x00000001</span>, <span class="string">b&quot;&quot;</span>);
<span class="ident">do_test</span>(<span class="number">0x00620062</span>, <span class="string">b&quot;a&quot;</span>);
<span class="ident">do_test</span>(<span class="number">0x024d0127</span>, <span class="string">b&quot;abc&quot;</span>);
<span class="ident">do_test</span>(<span class="number">0x29750586</span>, <span class="string">b&quot;message digest&quot;</span>);
<span class="ident">do_test</span>(<span class="number">0x90860b20</span>, <span class="string">b&quot;abcdefghijklmnopqrstuvwxyz&quot;</span>);
<span class="ident">do_test</span>(<span class="number">0x8adb150c</span>, <span class="string">b&quot;ABCDEFGHIJKLMNOPQRSTUVWXYZ\
abcdefghijklmnopqrstuvwxyz\
0123456789&quot;</span>);
<span class="ident">do_test</span>(<span class="number">0x97b61069</span>, <span class="string">b&quot;1234567890123456789012345678901234567890\
1234567890123456789012345678901234567890&quot;</span>);
<span class="ident">do_test</span>(<span class="number">0xD6251498</span>, <span class="kw-2">&amp;</span>[<span class="number">255</span>; <span class="number">64000</span>]);
}
<span class="attribute">#[<span class="ident">test</span>]</span>
<span class="kw">fn</span> <span class="ident">compare</span>() {
<span class="kw">let</span> <span class="kw-2">mut</span> <span class="ident">rng</span> <span class="op">=</span> <span class="ident">rand</span>::<span class="ident">thread_rng</span>();
<span class="kw">let</span> <span class="kw-2">mut</span> <span class="ident">data</span> <span class="op">=</span> <span class="macro">vec</span><span class="macro">!</span>[<span class="number">0u8</span>; <span class="number">5589</span>];
<span class="kw">for</span> <span class="ident">size</span> <span class="kw">in</span> [<span class="number">0</span>, <span class="number">1</span>, <span class="number">3</span>, <span class="number">4</span>, <span class="number">5</span>, <span class="number">31</span>, <span class="number">32</span>, <span class="number">33</span>, <span class="number">67</span>,
<span class="number">5550</span>, <span class="number">5552</span>, <span class="number">5553</span>, <span class="number">5568</span>, <span class="number">5584</span>, <span class="number">5589</span>].<span class="ident">iter</span>().<span class="ident">cloned</span>() {
<span class="ident">rng</span>.<span class="ident">fill_bytes</span>(<span class="kw-2">&amp;</span><span class="kw-2">mut</span> <span class="ident">data</span>[..<span class="ident">size</span>]);
<span class="kw">let</span> <span class="ident">r1</span> <span class="op">=</span> <span class="ident">io</span>::<span class="ident">Cursor</span>::<span class="ident">new</span>(<span class="kw-2">&amp;</span><span class="ident">data</span>[..<span class="ident">size</span>]);
<span class="kw">let</span> <span class="ident">r2</span> <span class="op">=</span> <span class="ident">r1</span>.<span class="ident">clone</span>();
<span class="kw">if</span> <span class="ident">adler32_slow</span>(<span class="ident">r1</span>).<span class="ident">unwrap</span>() <span class="op">!</span><span class="op">=</span> <span class="ident">adler32</span>(<span class="ident">r2</span>).<span class="ident">unwrap</span>() {
<span class="macro">panic</span><span class="macro">!</span>(<span class="string">&quot;Comparison failed, size={}&quot;</span>, <span class="ident">size</span>);
}
}
}
<span class="attribute">#[<span class="ident">test</span>]</span>
<span class="kw">fn</span> <span class="ident">rolling</span>() {
<span class="macro">assert_eq</span><span class="macro">!</span>(<span class="ident">RollingAdler32</span>::<span class="ident">from_value</span>(<span class="number">0x01020304</span>).<span class="ident">hash</span>(), <span class="number">0x01020304</span>);
<span class="kw">fn</span> <span class="ident">do_test</span>(<span class="ident">a</span>: <span class="kw-2">&amp;</span>[<span class="ident">u8</span>], <span class="ident">b</span>: <span class="kw-2">&amp;</span>[<span class="ident">u8</span>]) {
<span class="kw">let</span> <span class="kw-2">mut</span> <span class="ident">total</span> <span class="op">=</span> <span class="ident">Vec</span>::<span class="ident">with_capacity</span>(<span class="ident">a</span>.<span class="ident">len</span>() <span class="op">+</span> <span class="ident">b</span>.<span class="ident">len</span>());
<span class="ident">total</span>.<span class="ident">extend</span>(<span class="ident">a</span>);
<span class="ident">total</span>.<span class="ident">extend</span>(<span class="ident">b</span>);
<span class="kw">let</span> <span class="kw-2">mut</span> <span class="ident">h</span> <span class="op">=</span> <span class="ident">RollingAdler32</span>::<span class="ident">from_buffer</span>(<span class="kw-2">&amp;</span><span class="ident">total</span>[..(<span class="ident">b</span>.<span class="ident">len</span>())]);
<span class="kw">for</span> <span class="ident">i</span> <span class="kw">in</span> <span class="number">0</span>..(<span class="ident">a</span>.<span class="ident">len</span>()) {
<span class="ident">h</span>.<span class="ident">remove</span>(<span class="ident">b</span>.<span class="ident">len</span>(), <span class="ident">a</span>[<span class="ident">i</span>]);
<span class="ident">h</span>.<span class="ident">update</span>(<span class="ident">total</span>[<span class="ident">b</span>.<span class="ident">len</span>() <span class="op">+</span> <span class="ident">i</span>]);
}
<span class="macro">assert_eq</span><span class="macro">!</span>(<span class="ident">h</span>.<span class="ident">hash</span>(), <span class="ident">adler32</span>(<span class="ident">b</span>).<span class="ident">unwrap</span>());
}
<span class="ident">do_test</span>(<span class="string">b&quot;a&quot;</span>, <span class="string">b&quot;b&quot;</span>);
<span class="ident">do_test</span>(<span class="string">b&quot;&quot;</span>, <span class="string">b&quot;this a test&quot;</span>);
<span class="ident">do_test</span>(<span class="string">b&quot;th&quot;</span>, <span class="string">b&quot;is a test&quot;</span>);
<span class="ident">do_test</span>(<span class="string">b&quot;this a &quot;</span>, <span class="string">b&quot;test&quot;</span>);
}
<span class="attribute">#[<span class="ident">test</span>]</span>
<span class="kw">fn</span> <span class="ident">long_window_remove</span>() {
<span class="kw">let</span> <span class="kw-2">mut</span> <span class="ident">hash</span> <span class="op">=</span> <span class="ident">RollingAdler32</span>::<span class="ident">new</span>();
<span class="kw">let</span> <span class="ident">w</span> <span class="op">=</span> <span class="number">65536</span>;
<span class="macro">assert</span><span class="macro">!</span>(<span class="ident">w</span> <span class="kw">as</span> <span class="ident">u32</span> <span class="op">&gt;</span> <span class="ident">BASE</span>);
<span class="kw">let</span> <span class="kw-2">mut</span> <span class="ident">bytes</span> <span class="op">=</span> <span class="macro">vec</span><span class="macro">!</span>[<span class="number">0</span>; <span class="ident">w</span><span class="kw-2">*</span><span class="number">3</span>];
<span class="kw">for</span> (<span class="ident">i</span>, <span class="ident">b</span>) <span class="kw">in</span> <span class="ident">bytes</span>.<span class="ident">iter_mut</span>().<span class="ident">enumerate</span>() {
<span class="kw-2">*</span><span class="ident">b</span> <span class="op">=</span> <span class="ident">i</span> <span class="kw">as</span> <span class="ident">u8</span>;
}
<span class="kw">for</span> (<span class="ident">i</span>, <span class="ident">b</span>) <span class="kw">in</span> <span class="ident">bytes</span>.<span class="ident">iter</span>().<span class="ident">enumerate</span>() {
<span class="kw">if</span> <span class="ident">i</span> <span class="op">&gt;</span><span class="op">=</span> <span class="ident">w</span> {
<span class="ident">hash</span>.<span class="ident">remove</span>(<span class="ident">w</span>, <span class="ident">bytes</span>[<span class="ident">i</span> <span class="op">-</span> <span class="ident">w</span>]);
}
<span class="ident">hash</span>.<span class="ident">update</span>(<span class="kw-2">*</span><span class="ident">b</span>);
<span class="kw">if</span> <span class="ident">i</span> <span class="op">&gt;</span> <span class="number">0</span> <span class="kw-2">&amp;</span><span class="op">&amp;</span> <span class="ident">i</span> <span class="op">%</span> <span class="ident">w</span> <span class="op">=</span><span class="op">=</span> <span class="number">0</span> {
<span class="macro">assert_eq</span><span class="macro">!</span>(<span class="ident">hash</span>.<span class="ident">hash</span>(), <span class="number">0x433a8772</span>);
}
}
<span class="macro">assert_eq</span><span class="macro">!</span>(<span class="ident">hash</span>.<span class="ident">hash</span>(), <span class="number">0xbbba8772</span>);
}
}
</pre></div>
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