| <!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/fmp/.cargo/registry/src/github.com-1ecc6299db9ec823/regex-0.1.80/src/utf8.rs`."> |
| <meta name="keywords" content="rust, rustlang, rust-lang"> |
| |
| <title>utf8.rs.html -- source</title> |
| |
| <link rel="stylesheet" type="text/css" href="../../normalize.css"> |
| <link rel="stylesheet" type="text/css" href="../../rustdoc.css"> |
| <link rel="stylesheet" type="text/css" href="../../main.css"> |
| |
| |
| <link rel="shortcut icon" href="https://www.rust-lang.org/favicon.ico"> |
| |
| </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"> |
| <a href='../../regex/index.html'><img src='https://www.rust-lang.org/logos/rust-logo-128x128-blk-v2.png' alt='logo' width='100'></a> |
| |
| </nav> |
| |
| <nav class="sub"> |
| <form class="search-form js-only"> |
| <div class="search-container"> |
| <input class="search-input" name="search" |
| autocomplete="off" |
| placeholder="Click or press ‘S’ to search, ‘?’ for more options…" |
| type="search"> |
| </div> |
| </form> |
| </nav> |
| |
| <section id='main' class="content"><pre class="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> |
| <span id="71"> 71</span> |
| <span id="72"> 72</span> |
| <span id="73"> 73</span> |
| <span id="74"> 74</span> |
| <span id="75"> 75</span> |
| <span id="76"> 76</span> |
| <span id="77"> 77</span> |
| <span id="78"> 78</span> |
| <span id="79"> 79</span> |
| <span id="80"> 80</span> |
| <span id="81"> 81</span> |
| <span id="82"> 82</span> |
| <span id="83"> 83</span> |
| <span id="84"> 84</span> |
| <span id="85"> 85</span> |
| <span id="86"> 86</span> |
| <span id="87"> 87</span> |
| <span id="88"> 88</span> |
| <span id="89"> 89</span> |
| <span id="90"> 90</span> |
| <span id="91"> 91</span> |
| <span id="92"> 92</span> |
| <span id="93"> 93</span> |
| <span id="94"> 94</span> |
| <span id="95"> 95</span> |
| <span id="96"> 96</span> |
| <span id="97"> 97</span> |
| <span id="98"> 98</span> |
| <span id="99"> 99</span> |
| <span id="100">100</span> |
| <span id="101">101</span> |
| <span id="102">102</span> |
| <span id="103">103</span> |
| <span id="104">104</span> |
| <span id="105">105</span> |
| <span id="106">106</span> |
| <span id="107">107</span> |
| <span id="108">108</span> |
| <span id="109">109</span> |
| <span id="110">110</span> |
| <span id="111">111</span> |
| <span id="112">112</span> |
| <span id="113">113</span> |
| <span id="114">114</span> |
| <span id="115">115</span> |
| <span id="116">116</span> |
| <span id="117">117</span> |
| <span id="118">118</span> |
| <span id="119">119</span> |
| <span id="120">120</span> |
| <span id="121">121</span> |
| <span id="122">122</span> |
| <span id="123">123</span> |
| <span id="124">124</span> |
| <span id="125">125</span> |
| <span id="126">126</span> |
| <span id="127">127</span> |
| <span id="128">128</span> |
| <span id="129">129</span> |
| <span id="130">130</span> |
| <span id="131">131</span> |
| <span id="132">132</span> |
| <span id="133">133</span> |
| <span id="134">134</span> |
| <span id="135">135</span> |
| <span id="136">136</span> |
| <span id="137">137</span> |
| <span id="138">138</span> |
| <span id="139">139</span> |
| <span id="140">140</span> |
| <span id="141">141</span> |
| <span id="142">142</span> |
| <span id="143">143</span> |
| <span id="144">144</span> |
| <span id="145">145</span> |
| <span id="146">146</span> |
| <span id="147">147</span> |
| <span id="148">148</span> |
| <span id="149">149</span> |
| <span id="150">150</span> |
| <span id="151">151</span> |
| <span id="152">152</span> |
| <span id="153">153</span> |
| <span id="154">154</span> |
| <span id="155">155</span> |
| <span id="156">156</span> |
| <span id="157">157</span> |
| <span id="158">158</span> |
| <span id="159">159</span> |
| <span id="160">160</span> |
| <span id="161">161</span> |
| <span id="162">162</span> |
| <span id="163">163</span> |
| <span id="164">164</span> |
| <span id="165">165</span> |
| <span id="166">166</span> |
| <span id="167">167</span> |
| <span id="168">168</span> |
| <span id="169">169</span> |
| <span id="170">170</span> |
| <span id="171">171</span> |
| <span id="172">172</span> |
| <span id="173">173</span> |
| <span id="174">174</span> |
| <span id="175">175</span> |
| <span id="176">176</span> |
| <span id="177">177</span> |
| <span id="178">178</span> |
| <span id="179">179</span> |
| <span id="180">180</span> |
| <span id="181">181</span> |
| <span id="182">182</span> |
| <span id="183">183</span> |
| <span id="184">184</span> |
| <span id="185">185</span> |
| <span id="186">186</span> |
| <span id="187">187</span> |
| <span id="188">188</span> |
| <span id="189">189</span> |
| <span id="190">190</span> |
| <span id="191">191</span> |
| <span id="192">192</span> |
| <span id="193">193</span> |
| <span id="194">194</span> |
| <span id="195">195</span> |
| <span id="196">196</span> |
| <span id="197">197</span> |
| <span id="198">198</span> |
| <span id="199">199</span> |
| <span id="200">200</span> |
| <span id="201">201</span> |
| <span id="202">202</span> |
| <span id="203">203</span> |
| <span id="204">204</span> |
| <span id="205">205</span> |
| <span id="206">206</span> |
| <span id="207">207</span> |
| <span id="208">208</span> |
| <span id="209">209</span> |
| <span id="210">210</span> |
| <span id="211">211</span> |
| <span id="212">212</span> |
| <span id="213">213</span> |
| <span id="214">214</span> |
| <span id="215">215</span> |
| <span id="216">216</span> |
| <span id="217">217</span> |
| <span id="218">218</span> |
| <span id="219">219</span> |
| <span id="220">220</span> |
| <span id="221">221</span> |
| <span id="222">222</span> |
| <span id="223">223</span> |
| <span id="224">224</span> |
| <span id="225">225</span> |
| <span id="226">226</span> |
| <span id="227">227</span> |
| <span id="228">228</span> |
| <span id="229">229</span> |
| <span id="230">230</span> |
| <span id="231">231</span> |
| <span id="232">232</span> |
| <span id="233">233</span> |
| <span id="234">234</span> |
| <span id="235">235</span> |
| <span id="236">236</span> |
| <span id="237">237</span> |
| <span id="238">238</span> |
| <span id="239">239</span> |
| <span id="240">240</span> |
| <span id="241">241</span> |
| <span id="242">242</span> |
| <span id="243">243</span> |
| <span id="244">244</span> |
| <span id="245">245</span> |
| <span id="246">246</span> |
| <span id="247">247</span> |
| <span id="248">248</span> |
| <span id="249">249</span> |
| <span id="250">250</span> |
| <span id="251">251</span> |
| <span id="252">252</span> |
| <span id="253">253</span> |
| <span id="254">254</span> |
| <span id="255">255</span> |
| <span id="256">256</span> |
| <span id="257">257</span> |
| <span id="258">258</span> |
| <span id="259">259</span> |
| <span id="260">260</span> |
| <span id="261">261</span> |
| <span id="262">262</span> |
| <span id="263">263</span> |
| <span id="264">264</span> |
| <span id="265">265</span> |
| <span id="266">266</span> |
| <span id="267">267</span> |
| <span id="268">268</span> |
| <span id="269">269</span> |
| <span id="270">270</span> |
| </pre><pre class="rust "> |
| <span class="doccomment">/// A few elementary UTF-8 encoding and decoding functions used by the matching</span> |
| <span class="doccomment">/// engines.</span> |
| <span class="doccomment">///</span> |
| <span class="doccomment">/// In an ideal world, the matching engines operate on `&str` and we can just</span> |
| <span class="doccomment">/// lean on the standard library for all our UTF-8 needs. However, to support</span> |
| <span class="doccomment">/// byte based regexes (that can match on arbitrary bytes which may contain</span> |
| <span class="doccomment">/// UTF-8), we need to be capable of searching and decoding UTF-8 on a `&[u8]`.</span> |
| <span class="doccomment">/// The standard library doesn't really recognize this use case, so we have</span> |
| <span class="doccomment">/// to build it out ourselves.</span> |
| <span class="doccomment">///</span> |
| <span class="doccomment">/// Should this be factored out into a separate crate? It seems independently</span> |
| <span class="doccomment">/// useful. There are other crates that already exist (e.g., `utf-8`) that have</span> |
| <span class="doccomment">/// overlapping use cases. Not sure what to do.</span> |
| |
| <span class="kw">use</span> <span class="ident">std</span>::<span class="ident">char</span>; |
| |
| <span class="kw">const</span> <span class="ident">TAG_CONT</span>: <span class="ident">u8</span> <span class="op">=</span> <span class="number">0b1000_0000</span>; |
| <span class="kw">const</span> <span class="ident">TAG_TWO</span>: <span class="ident">u8</span> <span class="op">=</span> <span class="number">0b1100_0000</span>; |
| <span class="kw">const</span> <span class="ident">TAG_THREE</span>: <span class="ident">u8</span> <span class="op">=</span> <span class="number">0b1110_0000</span>; |
| <span class="kw">const</span> <span class="ident">TAG_FOUR</span>: <span class="ident">u8</span> <span class="op">=</span> <span class="number">0b1111_0000</span>; |
| |
| <span class="doccomment">/// Returns the smallest possible index of the next valid UTF-8 sequence</span> |
| <span class="doccomment">/// starting after `i`.</span> |
| <span class="kw">pub</span> <span class="kw">fn</span> <span class="ident">next_utf8</span>(<span class="ident">text</span>: <span class="kw-2">&</span>[<span class="ident">u8</span>], <span class="ident">i</span>: <span class="ident">usize</span>) <span class="op">-></span> <span class="ident">usize</span> { |
| <span class="kw">let</span> <span class="ident">b</span> <span class="op">=</span> <span class="kw">match</span> <span class="ident">text</span>.<span class="ident">get</span>(<span class="ident">i</span>) { |
| <span class="prelude-val">None</span> <span class="op">=></span> <span class="kw">return</span> <span class="ident">i</span> <span class="op">+</span> <span class="number">1</span>, |
| <span class="prelude-val">Some</span>(<span class="kw-2">&</span><span class="ident">b</span>) <span class="op">=></span> <span class="ident">b</span>, |
| }; |
| <span class="kw">let</span> <span class="ident">inc</span> <span class="op">=</span> <span class="kw">if</span> <span class="ident">b</span> <span class="op"><=</span> <span class="number">0x7F</span> { |
| <span class="number">1</span> |
| } <span class="kw">else</span> <span class="kw">if</span> <span class="ident">b</span> <span class="op"><=</span> <span class="number">0b110_11111</span> { |
| <span class="number">2</span> |
| } <span class="kw">else</span> <span class="kw">if</span> <span class="ident">b</span> <span class="op"><=</span> <span class="number">0b1110_1111</span> { |
| <span class="number">3</span> |
| } <span class="kw">else</span> { |
| <span class="number">4</span> |
| }; |
| <span class="ident">i</span> <span class="op">+</span> <span class="ident">inc</span> |
| } |
| |
| <span class="doccomment">/// Encode the given Unicode character to `dst` as a single UTF-8 sequence.</span> |
| <span class="doccomment">///</span> |
| <span class="doccomment">/// If `dst` is not long enough, then `None` is returned. Otherwise, the number</span> |
| <span class="doccomment">/// of bytes written is returned.</span> |
| <span class="attribute">#[<span class="ident">allow</span>(<span class="ident">dead_code</span>)]</span> |
| <span class="attribute">#[<span class="ident">inline</span>]</span> |
| <span class="kw">pub</span> <span class="kw">fn</span> <span class="ident">encode_utf8</span>(<span class="ident">character</span>: <span class="ident">char</span>, <span class="ident">dst</span>: <span class="kw-2">&</span><span class="kw-2">mut</span> [<span class="ident">u8</span>]) <span class="op">-></span> <span class="prelude-ty">Option</span><span class="op"><</span><span class="ident">usize</span><span class="op">></span> { |
| <span class="kw">let</span> <span class="ident">code</span> <span class="op">=</span> <span class="ident">character</span> <span class="kw">as</span> <span class="ident">u32</span>; |
| <span class="kw">if</span> <span class="ident">code</span> <span class="op"><=</span> <span class="number">0x7F</span> <span class="op">&&</span> <span class="op">!</span><span class="ident">dst</span>.<span class="ident">is_empty</span>() { |
| <span class="ident">dst</span>[<span class="number">0</span>] <span class="op">=</span> <span class="ident">code</span> <span class="kw">as</span> <span class="ident">u8</span>; |
| <span class="prelude-val">Some</span>(<span class="number">1</span>) |
| } <span class="kw">else</span> <span class="kw">if</span> <span class="ident">code</span> <span class="op"><=</span> <span class="number">0x7FF</span> <span class="op">&&</span> <span class="ident">dst</span>.<span class="ident">len</span>() <span class="op">>=</span> <span class="number">2</span> { |
| <span class="ident">dst</span>[<span class="number">0</span>] <span class="op">=</span> (<span class="ident">code</span> <span class="op">>></span> <span class="number">6</span> <span class="op">&</span> <span class="number">0x1F</span>) <span class="kw">as</span> <span class="ident">u8</span> <span class="op">|</span> <span class="ident">TAG_TWO</span>; |
| <span class="ident">dst</span>[<span class="number">1</span>] <span class="op">=</span> (<span class="ident">code</span> <span class="op">&</span> <span class="number">0x3F</span>) <span class="kw">as</span> <span class="ident">u8</span> <span class="op">|</span> <span class="ident">TAG_CONT</span>; |
| <span class="prelude-val">Some</span>(<span class="number">2</span>) |
| } <span class="kw">else</span> <span class="kw">if</span> <span class="ident">code</span> <span class="op"><=</span> <span class="number">0xFFFF</span> <span class="op">&&</span> <span class="ident">dst</span>.<span class="ident">len</span>() <span class="op">>=</span> <span class="number">3</span> { |
| <span class="ident">dst</span>[<span class="number">0</span>] <span class="op">=</span> (<span class="ident">code</span> <span class="op">>></span> <span class="number">12</span> <span class="op">&</span> <span class="number">0x0F</span>) <span class="kw">as</span> <span class="ident">u8</span> <span class="op">|</span> <span class="ident">TAG_THREE</span>; |
| <span class="ident">dst</span>[<span class="number">1</span>] <span class="op">=</span> (<span class="ident">code</span> <span class="op">>></span> <span class="number">6</span> <span class="op">&</span> <span class="number">0x3F</span>) <span class="kw">as</span> <span class="ident">u8</span> <span class="op">|</span> <span class="ident">TAG_CONT</span>; |
| <span class="ident">dst</span>[<span class="number">2</span>] <span class="op">=</span> (<span class="ident">code</span> <span class="op">&</span> <span class="number">0x3F</span>) <span class="kw">as</span> <span class="ident">u8</span> <span class="op">|</span> <span class="ident">TAG_CONT</span>; |
| <span class="prelude-val">Some</span>(<span class="number">3</span>) |
| } <span class="kw">else</span> <span class="kw">if</span> <span class="ident">dst</span>.<span class="ident">len</span>() <span class="op">>=</span> <span class="number">4</span> { |
| <span class="ident">dst</span>[<span class="number">0</span>] <span class="op">=</span> (<span class="ident">code</span> <span class="op">>></span> <span class="number">18</span> <span class="op">&</span> <span class="number">0x07</span>) <span class="kw">as</span> <span class="ident">u8</span> <span class="op">|</span> <span class="ident">TAG_FOUR</span>; |
| <span class="ident">dst</span>[<span class="number">1</span>] <span class="op">=</span> (<span class="ident">code</span> <span class="op">>></span> <span class="number">12</span> <span class="op">&</span> <span class="number">0x3F</span>) <span class="kw">as</span> <span class="ident">u8</span> <span class="op">|</span> <span class="ident">TAG_CONT</span>; |
| <span class="ident">dst</span>[<span class="number">2</span>] <span class="op">=</span> (<span class="ident">code</span> <span class="op">>></span> <span class="number">6</span> <span class="op">&</span> <span class="number">0x3F</span>) <span class="kw">as</span> <span class="ident">u8</span> <span class="op">|</span> <span class="ident">TAG_CONT</span>; |
| <span class="ident">dst</span>[<span class="number">3</span>] <span class="op">=</span> (<span class="ident">code</span> <span class="op">&</span> <span class="number">0x3F</span>) <span class="kw">as</span> <span class="ident">u8</span> <span class="op">|</span> <span class="ident">TAG_CONT</span>; |
| <span class="prelude-val">Some</span>(<span class="number">4</span>) |
| } <span class="kw">else</span> { |
| <span class="prelude-val">None</span> |
| } |
| } |
| |
| <span class="doccomment">/// Decode a single UTF-8 sequence into a single Unicode codepoint from `src`.</span> |
| <span class="doccomment">///</span> |
| <span class="doccomment">/// If no valid UTF-8 sequence could be found, then `None` is returned.</span> |
| <span class="doccomment">/// Otherwise, the decoded codepoint and the number of bytes read is returned.</span> |
| <span class="doccomment">/// The number of bytes read (for a valid UTF-8 sequence) is guaranteed to be</span> |
| <span class="doccomment">/// 1, 2, 3 or 4.</span> |
| <span class="doccomment">///</span> |
| <span class="doccomment">/// Note that a UTF-8 sequence is invalid if it is incorrect UTF-8, encodes a</span> |
| <span class="doccomment">/// codepoint that is out of range (surrogate codepoints are out of range) or</span> |
| <span class="doccomment">/// is not the shortest possible UTF-8 sequence for that codepoint.</span> |
| <span class="attribute">#[<span class="ident">inline</span>]</span> |
| <span class="kw">pub</span> <span class="kw">fn</span> <span class="ident">decode_utf8</span>(<span class="ident">src</span>: <span class="kw-2">&</span>[<span class="ident">u8</span>]) <span class="op">-></span> <span class="prelude-ty">Option</span><span class="op"><</span>(<span class="ident">char</span>, <span class="ident">usize</span>)<span class="op">></span> { |
| <span class="kw">let</span> <span class="ident">b0</span> <span class="op">=</span> <span class="kw">match</span> <span class="ident">src</span>.<span class="ident">get</span>(<span class="number">0</span>) { |
| <span class="prelude-val">None</span> <span class="op">=></span> <span class="kw">return</span> <span class="prelude-val">None</span>, |
| <span class="prelude-val">Some</span>(<span class="kw-2">&</span><span class="ident">b</span>) <span class="kw">if</span> <span class="ident">b</span> <span class="op"><=</span> <span class="number">0x7F</span> <span class="op">=></span> <span class="kw">return</span> <span class="prelude-val">Some</span>((<span class="ident">b</span> <span class="kw">as</span> <span class="ident">char</span>, <span class="number">1</span>)), |
| <span class="prelude-val">Some</span>(<span class="kw-2">&</span><span class="ident">b</span>) <span class="op">=></span> <span class="ident">b</span>, |
| }; |
| <span class="kw">match</span> <span class="ident">b0</span> { |
| <span class="number">0b110_00000</span> ... <span class="number">0b110_11111</span> <span class="op">=></span> { |
| <span class="kw">if</span> <span class="ident">src</span>.<span class="ident">len</span>() <span class="op"><</span> <span class="number">2</span> { |
| <span class="kw">return</span> <span class="prelude-val">None</span>; |
| } |
| <span class="kw">let</span> <span class="ident">b1</span> <span class="op">=</span> <span class="ident">src</span>[<span class="number">1</span>]; |
| <span class="kw">let</span> <span class="ident">cp</span> <span class="op">=</span> ((<span class="ident">b0</span> <span class="op">&</span> <span class="op">!</span><span class="ident">TAG_TWO</span>) <span class="kw">as</span> <span class="ident">u32</span>) <span class="op"><<</span> <span class="number">6</span> |
| <span class="op">|</span> ((<span class="ident">b1</span> <span class="op">&</span> <span class="op">!</span><span class="ident">TAG_CONT</span>) <span class="kw">as</span> <span class="ident">u32</span>); |
| <span class="kw">match</span> <span class="ident">cp</span> { |
| <span class="number">0x80</span> ... <span class="number">0x7FF</span> <span class="op">=></span> <span class="ident">char</span>::<span class="ident">from_u32</span>(<span class="ident">cp</span>).<span class="ident">map</span>(<span class="op">|</span><span class="ident">cp</span><span class="op">|</span> (<span class="ident">cp</span>, <span class="number">2</span>)), |
| _ <span class="op">=></span> <span class="prelude-val">None</span>, |
| } |
| } |
| <span class="number">0b1110_0000</span> ... <span class="number">0b1110_1111</span> <span class="op">=></span> { |
| <span class="kw">if</span> <span class="ident">src</span>.<span class="ident">len</span>() <span class="op"><</span> <span class="number">3</span> { |
| <span class="kw">return</span> <span class="prelude-val">None</span>; |
| } |
| <span class="kw">let</span> (<span class="ident">b1</span>, <span class="ident">b2</span>) <span class="op">=</span> (<span class="ident">src</span>[<span class="number">1</span>], <span class="ident">src</span>[<span class="number">2</span>]); |
| <span class="kw">let</span> <span class="ident">cp</span> <span class="op">=</span> ((<span class="ident">b0</span> <span class="op">&</span> <span class="op">!</span><span class="ident">TAG_THREE</span>) <span class="kw">as</span> <span class="ident">u32</span>) <span class="op"><<</span> <span class="number">12</span> |
| <span class="op">|</span> ((<span class="ident">b1</span> <span class="op">&</span> <span class="op">!</span><span class="ident">TAG_CONT</span>) <span class="kw">as</span> <span class="ident">u32</span>) <span class="op"><<</span> <span class="number">6</span> |
| <span class="op">|</span> ((<span class="ident">b2</span> <span class="op">&</span> <span class="op">!</span><span class="ident">TAG_CONT</span>) <span class="kw">as</span> <span class="ident">u32</span>); |
| <span class="kw">match</span> <span class="ident">cp</span> { |
| <span class="comment">// char::from_u32 will disallow surrogate codepoints.</span> |
| <span class="number">0x800</span> ... <span class="number">0xFFFF</span> <span class="op">=></span> <span class="ident">char</span>::<span class="ident">from_u32</span>(<span class="ident">cp</span>).<span class="ident">map</span>(<span class="op">|</span><span class="ident">cp</span><span class="op">|</span> (<span class="ident">cp</span>, <span class="number">3</span>)), |
| _ <span class="op">=></span> <span class="prelude-val">None</span>, |
| } |
| } |
| <span class="number">0b11110_000</span> ... <span class="number">0b11110_111</span> <span class="op">=></span> { |
| <span class="kw">if</span> <span class="ident">src</span>.<span class="ident">len</span>() <span class="op"><</span> <span class="number">4</span> { |
| <span class="kw">return</span> <span class="prelude-val">None</span>; |
| } |
| <span class="kw">let</span> (<span class="ident">b1</span>, <span class="ident">b2</span>, <span class="ident">b3</span>) <span class="op">=</span> (<span class="ident">src</span>[<span class="number">1</span>], <span class="ident">src</span>[<span class="number">2</span>], <span class="ident">src</span>[<span class="number">3</span>]); |
| <span class="kw">let</span> <span class="ident">cp</span> <span class="op">=</span> ((<span class="ident">b0</span> <span class="op">&</span> <span class="op">!</span><span class="ident">TAG_FOUR</span>) <span class="kw">as</span> <span class="ident">u32</span>) <span class="op"><<</span> <span class="number">18</span> |
| <span class="op">|</span> ((<span class="ident">b1</span> <span class="op">&</span> <span class="op">!</span><span class="ident">TAG_CONT</span>) <span class="kw">as</span> <span class="ident">u32</span>) <span class="op"><<</span> <span class="number">12</span> |
| <span class="op">|</span> ((<span class="ident">b2</span> <span class="op">&</span> <span class="op">!</span><span class="ident">TAG_CONT</span>) <span class="kw">as</span> <span class="ident">u32</span>) <span class="op"><<</span> <span class="number">6</span> |
| <span class="op">|</span> ((<span class="ident">b3</span> <span class="op">&</span> <span class="op">!</span><span class="ident">TAG_CONT</span>) <span class="kw">as</span> <span class="ident">u32</span>); |
| <span class="kw">match</span> <span class="ident">cp</span> { |
| <span class="number">0x10000</span> ... <span class="number">0x10FFFF</span> <span class="op">=></span> <span class="ident">char</span>::<span class="ident">from_u32</span>(<span class="ident">cp</span>).<span class="ident">map</span>(<span class="op">|</span><span class="ident">cp</span><span class="op">|</span> (<span class="ident">cp</span>, <span class="number">4</span>)), |
| _ <span class="op">=></span> <span class="prelude-val">None</span>, |
| } |
| } |
| _ <span class="op">=></span> <span class="prelude-val">None</span>, |
| } |
| } |
| |
| <span class="doccomment">/// Like decode_utf8, but decodes the last UTF-8 sequence in `src` instead of</span> |
| <span class="doccomment">/// the first.</span> |
| <span class="kw">pub</span> <span class="kw">fn</span> <span class="ident">decode_last_utf8</span>(<span class="ident">src</span>: <span class="kw-2">&</span>[<span class="ident">u8</span>]) <span class="op">-></span> <span class="prelude-ty">Option</span><span class="op"><</span>(<span class="ident">char</span>, <span class="ident">usize</span>)<span class="op">></span> { |
| <span class="kw">if</span> <span class="ident">src</span>.<span class="ident">is_empty</span>() { |
| <span class="kw">return</span> <span class="prelude-val">None</span>; |
| } |
| <span class="kw">let</span> <span class="kw-2">mut</span> <span class="ident">start</span> <span class="op">=</span> <span class="ident">src</span>.<span class="ident">len</span>() <span class="op">-</span> <span class="number">1</span>; |
| <span class="kw">if</span> <span class="ident">src</span>[<span class="ident">start</span>] <span class="op"><=</span> <span class="number">0x7F</span> { |
| <span class="kw">return</span> <span class="prelude-val">Some</span>((<span class="ident">src</span>[<span class="ident">start</span>] <span class="kw">as</span> <span class="ident">char</span>, <span class="number">1</span>)); |
| } |
| <span class="kw">while</span> <span class="ident">start</span> <span class="op">></span> <span class="ident">src</span>.<span class="ident">len</span>().<span class="ident">saturating_sub</span>(<span class="number">4</span>) { |
| <span class="ident">start</span> <span class="op">-=</span> <span class="number">1</span>; |
| <span class="kw">if</span> <span class="ident">is_start_byte</span>(<span class="ident">src</span>[<span class="ident">start</span>]) { |
| <span class="kw">break</span>; |
| } |
| } |
| <span class="kw">match</span> <span class="ident">decode_utf8</span>(<span class="kw-2">&</span><span class="ident">src</span>[<span class="ident">start</span>..]) { |
| <span class="prelude-val">None</span> <span class="op">=></span> <span class="prelude-val">None</span>, |
| <span class="prelude-val">Some</span>((_, <span class="ident">n</span>)) <span class="kw">if</span> <span class="ident">n</span> <span class="op"><</span> <span class="ident">src</span>.<span class="ident">len</span>() <span class="op">-</span> <span class="ident">start</span> <span class="op">=></span> <span class="prelude-val">None</span>, |
| <span class="prelude-val">Some</span>((<span class="ident">cp</span>, <span class="ident">n</span>)) <span class="op">=></span> <span class="prelude-val">Some</span>((<span class="ident">cp</span>, <span class="ident">n</span>)), |
| } |
| } |
| |
| <span class="kw">fn</span> <span class="ident">is_start_byte</span>(<span class="ident">b</span>: <span class="ident">u8</span>) <span class="op">-></span> <span class="ident">bool</span> { |
| <span class="ident">b</span> <span class="op">&</span> <span class="number">0b11_000000</span> <span class="op">!=</span> <span class="number">0b1_0000000</span> |
| } |
| |
| <span class="attribute">#[<span class="ident">cfg</span>(<span class="ident">test</span>)]</span> |
| <span class="kw">mod</span> <span class="ident">tests</span> { |
| <span class="kw">use</span> <span class="ident">std</span>::<span class="ident">str</span>; |
| |
| <span class="kw">use</span> <span class="ident">quickcheck</span>::<span class="ident">quickcheck</span>; |
| |
| <span class="kw">use</span> <span class="kw">super</span>::{ |
| <span class="ident">TAG_CONT</span>, <span class="ident">TAG_TWO</span>, <span class="ident">TAG_THREE</span>, <span class="ident">TAG_FOUR</span>, |
| <span class="ident">decode_utf8</span>, <span class="ident">decode_last_utf8</span>, <span class="ident">encode_utf8</span>, |
| }; |
| |
| <span class="attribute">#[<span class="ident">test</span>]</span> |
| <span class="kw">fn</span> <span class="ident">prop_roundtrip</span>() { |
| <span class="kw">fn</span> <span class="ident">p</span>(<span class="ident">given_cp</span>: <span class="ident">char</span>) <span class="op">-></span> <span class="ident">bool</span> { |
| <span class="kw">let</span> <span class="kw-2">mut</span> <span class="ident">tmp</span> <span class="op">=</span> [<span class="number">0</span>; <span class="number">4</span>]; |
| <span class="kw">let</span> <span class="ident">encoded_len</span> <span class="op">=</span> <span class="ident">encode_utf8</span>(<span class="ident">given_cp</span>, <span class="kw-2">&</span><span class="kw-2">mut</span> <span class="ident">tmp</span>).<span class="ident">unwrap</span>(); |
| <span class="kw">let</span> (<span class="ident">got_cp</span>, <span class="ident">got_len</span>) <span class="op">=</span> <span class="ident">decode_utf8</span>(<span class="kw-2">&</span><span class="ident">tmp</span>[..<span class="ident">encoded_len</span>]).<span class="ident">unwrap</span>(); |
| <span class="ident">encoded_len</span> <span class="op">==</span> <span class="ident">got_len</span> <span class="op">&&</span> <span class="ident">given_cp</span> <span class="op">==</span> <span class="ident">got_cp</span> |
| } |
| <span class="ident">quickcheck</span>(<span class="ident">p</span> <span class="kw">as</span> <span class="kw">fn</span>(<span class="ident">char</span>) <span class="op">-></span> <span class="ident">bool</span>) |
| } |
| |
| <span class="attribute">#[<span class="ident">test</span>]</span> |
| <span class="kw">fn</span> <span class="ident">prop_roundtrip_last</span>() { |
| <span class="kw">fn</span> <span class="ident">p</span>(<span class="ident">given_cp</span>: <span class="ident">char</span>) <span class="op">-></span> <span class="ident">bool</span> { |
| <span class="kw">let</span> <span class="kw-2">mut</span> <span class="ident">tmp</span> <span class="op">=</span> [<span class="number">0</span>; <span class="number">4</span>]; |
| <span class="kw">let</span> <span class="ident">encoded_len</span> <span class="op">=</span> <span class="ident">encode_utf8</span>(<span class="ident">given_cp</span>, <span class="kw-2">&</span><span class="kw-2">mut</span> <span class="ident">tmp</span>).<span class="ident">unwrap</span>(); |
| <span class="kw">let</span> (<span class="ident">got_cp</span>, <span class="ident">got_len</span>) <span class="op">=</span> |
| <span class="ident">decode_last_utf8</span>(<span class="kw-2">&</span><span class="ident">tmp</span>[..<span class="ident">encoded_len</span>]).<span class="ident">unwrap</span>(); |
| <span class="ident">encoded_len</span> <span class="op">==</span> <span class="ident">got_len</span> <span class="op">&&</span> <span class="ident">given_cp</span> <span class="op">==</span> <span class="ident">got_cp</span> |
| } |
| <span class="ident">quickcheck</span>(<span class="ident">p</span> <span class="kw">as</span> <span class="kw">fn</span>(<span class="ident">char</span>) <span class="op">-></span> <span class="ident">bool</span>) |
| } |
| |
| <span class="attribute">#[<span class="ident">test</span>]</span> |
| <span class="kw">fn</span> <span class="ident">prop_encode_matches_std</span>() { |
| <span class="kw">fn</span> <span class="ident">p</span>(<span class="ident">cp</span>: <span class="ident">char</span>) <span class="op">-></span> <span class="ident">bool</span> { |
| <span class="kw">let</span> <span class="kw-2">mut</span> <span class="ident">got</span> <span class="op">=</span> [<span class="number">0</span>; <span class="number">4</span>]; |
| <span class="kw">let</span> <span class="ident">n</span> <span class="op">=</span> <span class="ident">encode_utf8</span>(<span class="ident">cp</span>, <span class="kw-2">&</span><span class="kw-2">mut</span> <span class="ident">got</span>).<span class="ident">unwrap</span>(); |
| <span class="kw">let</span> <span class="ident">expected</span> <span class="op">=</span> <span class="ident">cp</span>.<span class="ident">to_string</span>(); |
| <span class="kw-2">&</span><span class="ident">got</span>[..<span class="ident">n</span>] <span class="op">==</span> <span class="ident">expected</span>.<span class="ident">as_bytes</span>() |
| } |
| <span class="ident">quickcheck</span>(<span class="ident">p</span> <span class="kw">as</span> <span class="kw">fn</span>(<span class="ident">char</span>) <span class="op">-></span> <span class="ident">bool</span>) |
| } |
| |
| <span class="attribute">#[<span class="ident">test</span>]</span> |
| <span class="kw">fn</span> <span class="ident">prop_decode_matches_std</span>() { |
| <span class="kw">fn</span> <span class="ident">p</span>(<span class="ident">given_cp</span>: <span class="ident">char</span>) <span class="op">-></span> <span class="ident">bool</span> { |
| <span class="kw">let</span> <span class="kw-2">mut</span> <span class="ident">tmp</span> <span class="op">=</span> [<span class="number">0</span>; <span class="number">4</span>]; |
| <span class="kw">let</span> <span class="ident">n</span> <span class="op">=</span> <span class="ident">encode_utf8</span>(<span class="ident">given_cp</span>, <span class="kw-2">&</span><span class="kw-2">mut</span> <span class="ident">tmp</span>).<span class="ident">unwrap</span>(); |
| <span class="kw">let</span> (<span class="ident">got_cp</span>, _) <span class="op">=</span> <span class="ident">decode_utf8</span>(<span class="kw-2">&</span><span class="ident">tmp</span>[..<span class="ident">n</span>]).<span class="ident">unwrap</span>(); |
| <span class="kw">let</span> <span class="ident">expected_cp</span> <span class="op">=</span> |
| <span class="ident">str</span>::<span class="ident">from_utf8</span>(<span class="kw-2">&</span><span class="ident">tmp</span>[..<span class="ident">n</span>]).<span class="ident">unwrap</span>().<span class="ident">chars</span>().<span class="ident">next</span>().<span class="ident">unwrap</span>(); |
| <span class="ident">got_cp</span> <span class="op">==</span> <span class="ident">expected_cp</span> |
| } |
| <span class="ident">quickcheck</span>(<span class="ident">p</span> <span class="kw">as</span> <span class="kw">fn</span>(<span class="ident">char</span>) <span class="op">-></span> <span class="ident">bool</span>) |
| } |
| |
| <span class="attribute">#[<span class="ident">test</span>]</span> |
| <span class="kw">fn</span> <span class="ident">prop_decode_last_matches_std</span>() { |
| <span class="kw">fn</span> <span class="ident">p</span>(<span class="ident">given_cp</span>: <span class="ident">char</span>) <span class="op">-></span> <span class="ident">bool</span> { |
| <span class="kw">let</span> <span class="kw-2">mut</span> <span class="ident">tmp</span> <span class="op">=</span> [<span class="number">0</span>; <span class="number">4</span>]; |
| <span class="kw">let</span> <span class="ident">n</span> <span class="op">=</span> <span class="ident">encode_utf8</span>(<span class="ident">given_cp</span>, <span class="kw-2">&</span><span class="kw-2">mut</span> <span class="ident">tmp</span>).<span class="ident">unwrap</span>(); |
| <span class="kw">let</span> (<span class="ident">got_cp</span>, _) <span class="op">=</span> <span class="ident">decode_last_utf8</span>(<span class="kw-2">&</span><span class="ident">tmp</span>[..<span class="ident">n</span>]).<span class="ident">unwrap</span>(); |
| <span class="kw">let</span> <span class="ident">expected_cp</span> <span class="op">=</span> |
| <span class="ident">str</span>::<span class="ident">from_utf8</span>(<span class="kw-2">&</span><span class="ident">tmp</span>[..<span class="ident">n</span>]).<span class="ident">unwrap</span>() |
| .<span class="ident">chars</span>().<span class="ident">rev</span>().<span class="ident">next</span>().<span class="ident">unwrap</span>(); |
| <span class="ident">got_cp</span> <span class="op">==</span> <span class="ident">expected_cp</span> |
| } |
| <span class="ident">quickcheck</span>(<span class="ident">p</span> <span class="kw">as</span> <span class="kw">fn</span>(<span class="ident">char</span>) <span class="op">-></span> <span class="ident">bool</span>) |
| } |
| |
| <span class="attribute">#[<span class="ident">test</span>]</span> |
| <span class="kw">fn</span> <span class="ident">reject_invalid</span>() { |
| <span class="comment">// Invalid start byte</span> |
| <span class="macro">assert_eq</span><span class="macro">!</span>(<span class="ident">decode_utf8</span>(<span class="kw-2">&</span>[<span class="number">0xFF</span>]), <span class="prelude-val">None</span>); |
| <span class="comment">// Surrogate pair</span> |
| <span class="macro">assert_eq</span><span class="macro">!</span>(<span class="ident">decode_utf8</span>(<span class="kw-2">&</span>[<span class="number">0xED</span>, <span class="number">0xA0</span>, <span class="number">0x81</span>]), <span class="prelude-val">None</span>); |
| <span class="comment">// Bad lengths</span> |
| <span class="macro">assert_eq</span><span class="macro">!</span>(<span class="ident">decode_utf8</span>(<span class="kw-2">&</span>[<span class="number">0xC3</span>]), <span class="prelude-val">None</span>); <span class="comment">// 2 bytes</span> |
| <span class="macro">assert_eq</span><span class="macro">!</span>(<span class="ident">decode_utf8</span>(<span class="kw-2">&</span>[<span class="number">0xEF</span>, <span class="number">0xBF</span>]), <span class="prelude-val">None</span>); <span class="comment">// 3 bytes</span> |
| <span class="macro">assert_eq</span><span class="macro">!</span>(<span class="ident">decode_utf8</span>(<span class="kw-2">&</span>[<span class="number">0xF4</span>, <span class="number">0x8F</span>, <span class="number">0xBF</span>]), <span class="prelude-val">None</span>); <span class="comment">// 4 bytes</span> |
| <span class="comment">// Not a minimal UTF-8 sequence</span> |
| <span class="macro">assert_eq</span><span class="macro">!</span>(<span class="ident">decode_utf8</span>(<span class="kw-2">&</span>[<span class="ident">TAG_TWO</span>, <span class="ident">TAG_CONT</span> <span class="op">|</span> <span class="string">b'a'</span>]), <span class="prelude-val">None</span>); |
| <span class="macro">assert_eq</span><span class="macro">!</span>(<span class="ident">decode_utf8</span>(<span class="kw-2">&</span>[<span class="ident">TAG_THREE</span>, <span class="ident">TAG_CONT</span>, <span class="ident">TAG_CONT</span> <span class="op">|</span> <span class="string">b'a'</span>]), <span class="prelude-val">None</span>); |
| <span class="macro">assert_eq</span><span class="macro">!</span>(<span class="ident">decode_utf8</span>(<span class="kw-2">&</span>[ |
| <span class="ident">TAG_FOUR</span>, <span class="ident">TAG_CONT</span>, <span class="ident">TAG_CONT</span>, <span class="ident">TAG_CONT</span> <span class="op">|</span> <span class="string">b'a'</span>, |
| ]), <span class="prelude-val">None</span>); |
| } |
| |
| <span class="attribute">#[<span class="ident">test</span>]</span> |
| <span class="kw">fn</span> <span class="ident">reject_invalid_last</span>() { |
| <span class="comment">// Invalid start byte</span> |
| <span class="macro">assert_eq</span><span class="macro">!</span>(<span class="ident">decode_last_utf8</span>(<span class="kw-2">&</span>[<span class="number">0xFF</span>]), <span class="prelude-val">None</span>); |
| <span class="comment">// Surrogate pair</span> |
| <span class="macro">assert_eq</span><span class="macro">!</span>(<span class="ident">decode_last_utf8</span>(<span class="kw-2">&</span>[<span class="number">0xED</span>, <span class="number">0xA0</span>, <span class="number">0x81</span>]), <span class="prelude-val">None</span>); |
| <span class="comment">// Bad lengths</span> |
| <span class="macro">assert_eq</span><span class="macro">!</span>(<span class="ident">decode_last_utf8</span>(<span class="kw-2">&</span>[<span class="number">0xC3</span>]), <span class="prelude-val">None</span>); <span class="comment">// 2 bytes</span> |
| <span class="macro">assert_eq</span><span class="macro">!</span>(<span class="ident">decode_last_utf8</span>(<span class="kw-2">&</span>[<span class="number">0xEF</span>, <span class="number">0xBF</span>]), <span class="prelude-val">None</span>); <span class="comment">// 3 bytes</span> |
| <span class="macro">assert_eq</span><span class="macro">!</span>(<span class="ident">decode_last_utf8</span>(<span class="kw-2">&</span>[<span class="number">0xF4</span>, <span class="number">0x8F</span>, <span class="number">0xBF</span>]), <span class="prelude-val">None</span>); <span class="comment">// 4 bytes</span> |
| <span class="comment">// Not a minimal UTF-8 sequence</span> |
| <span class="macro">assert_eq</span><span class="macro">!</span>(<span class="ident">decode_last_utf8</span>(<span class="kw-2">&</span>[<span class="ident">TAG_TWO</span>, <span class="ident">TAG_CONT</span> <span class="op">|</span> <span class="string">b'a'</span>]), <span class="prelude-val">None</span>); |
| <span class="macro">assert_eq</span><span class="macro">!</span>(<span class="ident">decode_last_utf8</span>(<span class="kw-2">&</span>[ |
| <span class="ident">TAG_THREE</span>, <span class="ident">TAG_CONT</span>, <span class="ident">TAG_CONT</span> <span class="op">|</span> <span class="string">b'a'</span>, |
| ]), <span class="prelude-val">None</span>); |
| <span class="macro">assert_eq</span><span class="macro">!</span>(<span class="ident">decode_last_utf8</span>(<span class="kw-2">&</span>[ |
| <span class="ident">TAG_FOUR</span>, <span class="ident">TAG_CONT</span>, <span class="ident">TAG_CONT</span>, <span class="ident">TAG_CONT</span> <span class="op">|</span> <span class="string">b'a'</span>, |
| ]), <span class="prelude-val">None</span>); |
| } |
| } |
| </pre> |
| </section> |
| <section id='search' class="content hidden"></section> |
| |
| <section class="footer"></section> |
| |
| <aside id="help" class="hidden"> |
| <div> |
| <h1 class="hidden">Help</h1> |
| |
| <div class="shortcuts"> |
| <h2>Keyboard Shortcuts</h2> |
| |
| <dl> |
| <dt>?</dt> |
| <dd>Show this help dialog</dd> |
| <dt>S</dt> |
| <dd>Focus the search field</dd> |
| <dt>⇤</dt> |
| <dd>Move up in search results</dd> |
| <dt>⇥</dt> |
| <dd>Move down in search results</dd> |
| <dt>⏎</dt> |
| <dd>Go to active search result</dd> |
| <dt>+</dt> |
| <dd>Collapse/expand all sections</dd> |
| </dl> |
| </div> |
| |
| <div class="infos"> |
| <h2>Search Tricks</h2> |
| |
| <p> |
| Prefix searches with a type followed by a colon (e.g. |
| <code>fn:</code>) to restrict the search to a given type. |
| </p> |
| |
| <p> |
| Accepted types are: <code>fn</code>, <code>mod</code>, |
| <code>struct</code>, <code>enum</code>, |
| <code>trait</code>, <code>type</code>, <code>macro</code>, |
| and <code>const</code>. |
| </p> |
| |
| <p> |
| Search functions by type signature (e.g. |
| <code>vec -> usize</code> or <code>* -> vec</code>) |
| </p> |
| </div> |
| </div> |
| </aside> |
| |
| |
| |
| <script> |
| window.rootPath = "../../"; |
| window.currentCrate = "regex"; |
| </script> |
| <script src="../../main.js"></script> |
| <script defer src="../../search-index.js"></script> |
| </body> |
| </html> |
