| <!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 `common/rusty_leveldb_sgx/src/blockhandle.rs`."><meta name="keywords" content="rust, rustlang, rust-lang"><title>blockhandle.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="../../rusty_leveldb/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="../../rusty_leveldb/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> |
| <span id="2">2</span> |
| <span id="3">3</span> |
| <span id="4">4</span> |
| <span id="5">5</span> |
| <span id="6">6</span> |
| <span id="7">7</span> |
| <span id="8">8</span> |
| <span id="9">9</span> |
| <span id="10">10</span> |
| <span id="11">11</span> |
| <span id="12">12</span> |
| <span id="13">13</span> |
| <span id="14">14</span> |
| <span id="15">15</span> |
| <span id="16">16</span> |
| <span id="17">17</span> |
| <span id="18">18</span> |
| <span id="19">19</span> |
| <span id="20">20</span> |
| <span id="21">21</span> |
| <span id="22">22</span> |
| <span id="23">23</span> |
| <span id="24">24</span> |
| <span id="25">25</span> |
| <span id="26">26</span> |
| <span id="27">27</span> |
| <span id="28">28</span> |
| <span id="29">29</span> |
| <span id="30">30</span> |
| <span id="31">31</span> |
| <span id="32">32</span> |
| <span id="33">33</span> |
| <span id="34">34</span> |
| <span id="35">35</span> |
| <span id="36">36</span> |
| <span id="37">37</span> |
| <span id="38">38</span> |
| <span id="39">39</span> |
| <span id="40">40</span> |
| <span id="41">41</span> |
| <span id="42">42</span> |
| <span id="43">43</span> |
| <span id="44">44</span> |
| <span id="45">45</span> |
| <span id="46">46</span> |
| <span id="47">47</span> |
| <span id="48">48</span> |
| <span id="49">49</span> |
| <span id="50">50</span> |
| <span id="51">51</span> |
| <span id="52">52</span> |
| <span id="53">53</span> |
| <span id="54">54</span> |
| <span id="55">55</span> |
| <span id="56">56</span> |
| <span id="57">57</span> |
| <span id="58">58</span> |
| <span id="59">59</span> |
| <span id="60">60</span> |
| <span id="61">61</span> |
| <span id="62">62</span> |
| <span id="63">63</span> |
| <span id="64">64</span> |
| <span id="65">65</span> |
| <span id="66">66</span> |
| <span id="67">67</span> |
| <span id="68">68</span> |
| <span id="69">69</span> |
| <span id="70">70</span> |
| </pre><pre class="rust"><code><span class="kw">use </span>integer_encoding::VarInt; |
| |
| <span class="doccomment">/// Contains an offset and a length (or size); can be efficiently encoded in to varints. This is |
| /// used typically as file-internal pointer in table (SSTable) files. For example, the index block |
| /// in an SSTable is a block of (key = largest key in block) -> (value = encoded blockhandle of |
| /// block). |
| </span><span class="attribute">#[derive(Debug, Clone)] |
| </span><span class="kw">pub struct </span>BlockHandle { |
| offset: usize, |
| size: usize, |
| } |
| |
| <span class="kw">impl </span>BlockHandle { |
| <span class="doccomment">/// Decodes a block handle from `from` and returns a block handle |
| /// together with how many bytes were read from the slice. |
| </span><span class="kw">pub fn </span>decode(from: <span class="kw-2">&</span>[u8]) -> (BlockHandle, usize) { |
| <span class="kw">let </span>(off, offsize) = usize::decode_var(from); |
| <span class="kw">let </span>(sz, szsize) = usize::decode_var(<span class="kw-2">&</span>from[offsize..]); |
| |
| ( |
| BlockHandle { |
| offset: off, |
| size: sz, |
| }, |
| offsize + szsize, |
| ) |
| } |
| |
| <span class="kw">pub fn </span>new(offset: usize, size: usize) -> BlockHandle { |
| BlockHandle { offset, size } |
| } |
| |
| <span class="kw">pub fn </span>offset(<span class="kw-2">&</span><span class="self">self</span>) -> usize { |
| <span class="self">self</span>.offset |
| } |
| |
| <span class="kw">pub fn </span>size(<span class="kw-2">&</span><span class="self">self</span>) -> usize { |
| <span class="self">self</span>.size |
| } |
| |
| <span class="doccomment">/// Returns how many bytes were written, or 0 if the write failed because `dst` is too small. |
| </span><span class="kw">pub fn </span>encode_to(<span class="kw-2">&</span><span class="self">self</span>, dst: <span class="kw-2">&mut </span>[u8]) -> usize { |
| <span class="macro">assert!</span>(dst.len() >= <span class="self">self</span>.offset.required_space() + <span class="self">self</span>.size.required_space()); |
| |
| <span class="kw">let </span>off = <span class="self">self</span>.offset.encode_var(dst); |
| off + <span class="self">self</span>.size.encode_var(<span class="kw-2">&mut </span>dst[off..]) |
| } |
| } |
| |
| <span class="attribute">#[cfg(feature = <span class="string">"enclave_unit_test"</span>)] |
| </span><span class="kw">pub mod </span>tests { |
| <span class="kw">use super</span>::<span class="kw-2">*</span>; |
| <span class="kw">use </span>teaclave_test_utils::<span class="kw-2">*</span>; |
| |
| <span class="kw">pub fn </span>run_tests() -> bool { |
| <span class="macro">run_tests!</span>(test_blockhandle,) |
| } |
| |
| <span class="kw">fn </span>test_blockhandle() { |
| <span class="kw">let </span>bh = BlockHandle::new(<span class="number">890</span>, <span class="number">777</span>); |
| <span class="kw">let </span><span class="kw-2">mut </span>dst = [<span class="number">0 </span><span class="kw">as </span>u8; <span class="number">128</span>]; |
| <span class="kw">let </span>enc_sz = bh.encode_to(<span class="kw-2">&mut </span>dst[..]); |
| |
| <span class="kw">let </span>(bh2, dec_sz) = BlockHandle::decode(<span class="kw-2">&</span>dst); |
| |
| <span class="macro">assert_eq!</span>(enc_sz, dec_sz); |
| <span class="macro">assert_eq!</span>(bh.size(), bh2.size()); |
| <span class="macro">assert_eq!</span>(bh.offset(), bh2.offset()); |
| } |
| } |
| </code></pre></div> |
| </section></div></main><div id="rustdoc-vars" data-root-path="../../" data-current-crate="rusty_leveldb" data-themes="ayu,dark,light" data-resource-suffix="" data-rustdoc-version="1.66.0-nightly (5c8bff74b 2022-10-21)" ></div></body></html> |
