grpc/cpp/slice__cast_8h_source.html

152 lines
16 KiB
HTML

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "https://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<meta http-equiv="Content-Type" content="text/xhtml;charset=UTF-8"/>
<meta http-equiv="X-UA-Compatible" content="IE=9"/>
<meta name="generator" content="Doxygen 1.8.17"/>
<meta name="viewport" content="width=device-width, initial-scale=1"/>
<title>GRPC C++: include/grpc/event_engine/internal/slice_cast.h Source File</title>
<link href="tabs.css" rel="stylesheet" type="text/css"/>
<script type="text/javascript" src="jquery.js"></script>
<script type="text/javascript" src="dynsections.js"></script>
<link href="search/search.css" rel="stylesheet" type="text/css"/>
<script type="text/javascript" src="search/searchdata.js"></script>
<script type="text/javascript" src="search/search.js"></script>
<link href="doxygen.css" rel="stylesheet" type="text/css" />
</head>
<body>
<div id="top"><!-- do not remove this div, it is closed by doxygen! -->
<div id="titlearea">
<table cellspacing="0" cellpadding="0">
<tbody>
<tr style="height: 56px;">
<td id="projectalign" style="padding-left: 0.5em;">
<div id="projectname">GRPC C++
&#160;<span id="projectnumber">1.58.0</span>
</div>
</td>
</tr>
</tbody>
</table>
</div>
<!-- end header part -->
<!-- Generated by Doxygen 1.8.17 -->
<script type="text/javascript">
/* @license magnet:?xt=urn:btih:cf05388f2679ee054f2beb29a391d25f4e673ac3&amp;dn=gpl-2.0.txt GPL-v2 */
var searchBox = new SearchBox("searchBox", "search",false,'Search');
/* @license-end */
</script>
<script type="text/javascript" src="menudata.js"></script>
<script type="text/javascript" src="menu.js"></script>
<script type="text/javascript">
/* @license magnet:?xt=urn:btih:cf05388f2679ee054f2beb29a391d25f4e673ac3&amp;dn=gpl-2.0.txt GPL-v2 */
$(function() {
initMenu('',true,false,'search.php','Search');
$(document).ready(function() { init_search(); });
});
/* @license-end */</script>
<div id="main-nav"></div>
<!-- window showing the filter options -->
<div id="MSearchSelectWindow"
onmouseover="return searchBox.OnSearchSelectShow()"
onmouseout="return searchBox.OnSearchSelectHide()"
onkeydown="return searchBox.OnSearchSelectKey(event)">
</div>
<!-- iframe showing the search results (closed by default) -->
<div id="MSearchResultsWindow">
<iframe src="javascript:void(0)" frameborder="0"
name="MSearchResults" id="MSearchResults">
</iframe>
</div>
<div id="nav-path" class="navpath">
<ul>
<li class="navelem"><a class="el" href="dir_d44c64559bbebec7f509842c48db8b23.html">include</a></li><li class="navelem"><a class="el" href="dir_9d7a14d6d9adcbe4c35dbdb88d867e2e.html">grpc</a></li><li class="navelem"><a class="el" href="dir_bd8dffe728229f23f136e38dafaf5150.html">event_engine</a></li><li class="navelem"><a class="el" href="dir_f317bab89d176f7540f060919119ce81.html">internal</a></li> </ul>
</div>
</div><!-- top -->
<div class="header">
<div class="headertitle">
<div class="title">slice_cast.h</div> </div>
</div><!--header-->
<div class="contents">
<a href="slice__cast_8h.html">Go to the documentation of this file.</a><div class="fragment"><div class="line"><a name="l00001"></a><span class="lineno"> 1</span>&#160;<span class="comment">// Copyright 2022 gRPC authors.</span></div>
<div class="line"><a name="l00002"></a><span class="lineno"> 2</span>&#160;<span class="comment">//</span></div>
<div class="line"><a name="l00003"></a><span class="lineno"> 3</span>&#160;<span class="comment">// Licensed under the Apache License, Version 2.0 (the &quot;License&quot;);</span></div>
<div class="line"><a name="l00004"></a><span class="lineno"> 4</span>&#160;<span class="comment">// you may not use this file except in compliance with the License.</span></div>
<div class="line"><a name="l00005"></a><span class="lineno"> 5</span>&#160;<span class="comment">// You may obtain a copy of the License at</span></div>
<div class="line"><a name="l00006"></a><span class="lineno"> 6</span>&#160;<span class="comment">//</span></div>
<div class="line"><a name="l00007"></a><span class="lineno"> 7</span>&#160;<span class="comment">// http://www.apache.org/licenses/LICENSE-2.0</span></div>
<div class="line"><a name="l00008"></a><span class="lineno"> 8</span>&#160;<span class="comment">//</span></div>
<div class="line"><a name="l00009"></a><span class="lineno"> 9</span>&#160;<span class="comment">// Unless required by applicable law or agreed to in writing, software</span></div>
<div class="line"><a name="l00010"></a><span class="lineno"> 10</span>&#160;<span class="comment">// distributed under the License is distributed on an &quot;AS IS&quot; BASIS,</span></div>
<div class="line"><a name="l00011"></a><span class="lineno"> 11</span>&#160;<span class="comment">// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.</span></div>
<div class="line"><a name="l00012"></a><span class="lineno"> 12</span>&#160;<span class="comment">// See the License for the specific language governing permissions and</span></div>
<div class="line"><a name="l00013"></a><span class="lineno"> 13</span>&#160;<span class="comment">// limitations under the License.</span></div>
<div class="line"><a name="l00014"></a><span class="lineno"> 14</span>&#160; </div>
<div class="line"><a name="l00015"></a><span class="lineno"> 15</span>&#160;<span class="preprocessor">#ifndef GRPC_EVENT_ENGINE_INTERNAL_SLICE_CAST_H</span></div>
<div class="line"><a name="l00016"></a><span class="lineno"> 16</span>&#160;<span class="preprocessor">#define GRPC_EVENT_ENGINE_INTERNAL_SLICE_CAST_H</span></div>
<div class="line"><a name="l00017"></a><span class="lineno"> 17</span>&#160; </div>
<div class="line"><a name="l00018"></a><span class="lineno"> 18</span>&#160;<span class="keyword">namespace </span><a class="code" href="namespacegrpc__event__engine.html">grpc_event_engine</a> {</div>
<div class="line"><a name="l00019"></a><span class="lineno"> 19</span>&#160;<span class="keyword">namespace </span>experimental {</div>
<div class="line"><a name="l00020"></a><span class="lineno"> 20</span>&#160;<span class="keyword">namespace </span>internal {</div>
<div class="line"><a name="l00021"></a><span class="lineno"> 21</span>&#160; </div>
<div class="line"><a name="l00022"></a><span class="lineno"> 22</span>&#160;<span class="comment">// Opt-in trait class for slice conversions.</span></div>
<div class="line"><a name="l00023"></a><span class="lineno"> 23</span>&#160;<span class="comment">// Declare a specialization of this class for any types that are compatible</span></div>
<div class="line"><a name="l00024"></a><span class="lineno"> 24</span>&#160;<span class="comment">// with `SliceCast`. Both ways need to be declared (i.e. if</span></div>
<div class="line"><a name="l00025"></a><span class="lineno"> 25</span>&#160;<span class="comment">// SliceCastable&lt;A,B&gt; exists, you should declare</span></div>
<div class="line"><a name="l00026"></a><span class="lineno"> 26</span>&#160;<span class="comment">// SliceCastable&lt;B,A&gt; too).</span></div>
<div class="line"><a name="l00027"></a><span class="lineno"> 27</span>&#160;<span class="comment">// The type has no members, it&#39;s just the existance of the specialization that</span></div>
<div class="line"><a name="l00028"></a><span class="lineno"> 28</span>&#160;<span class="comment">// unlocks SliceCast usage for a type pair.</span></div>
<div class="line"><a name="l00029"></a><span class="lineno"> 29</span>&#160;<span class="keyword">template</span> &lt;<span class="keyword">typename</span> Result, <span class="keyword">typename</span> T&gt;</div>
<div class="line"><a name="l00030"></a><span class="lineno"><a class="line" href="structgrpc__event__engine_1_1experimental_1_1internal_1_1_slice_castable.html"> 30</a></span>&#160;<span class="keyword">struct </span><a class="code" href="structgrpc__event__engine_1_1experimental_1_1internal_1_1_slice_castable.html">SliceCastable</a>;</div>
<div class="line"><a name="l00031"></a><span class="lineno"> 31</span>&#160; </div>
<div class="line"><a name="l00032"></a><span class="lineno"> 32</span>&#160;<span class="comment">// This is strictly too wide, but consider all types to be SliceCast-able to</span></div>
<div class="line"><a name="l00033"></a><span class="lineno"> 33</span>&#160;<span class="comment">// themselves.</span></div>
<div class="line"><a name="l00034"></a><span class="lineno"> 34</span>&#160;<span class="comment">// Unfortunately this allows `const int&amp; x = SliceCast&lt;int&gt;(x);` which is kind</span></div>
<div class="line"><a name="l00035"></a><span class="lineno"> 35</span>&#160;<span class="comment">// of bogus.</span></div>
<div class="line"><a name="l00036"></a><span class="lineno"> 36</span>&#160;<span class="keyword">template</span> &lt;<span class="keyword">typename</span> A&gt;</div>
<div class="line"><a name="l00037"></a><span class="lineno"><a class="line" href="structgrpc__event__engine_1_1experimental_1_1internal_1_1_slice_castable_3_01_a_00_01_a_01_4.html"> 37</a></span>&#160;<span class="keyword">struct </span><a class="code" href="structgrpc__event__engine_1_1experimental_1_1internal_1_1_slice_castable.html">SliceCastable</a>&lt;A, A&gt; {};</div>
<div class="line"><a name="l00038"></a><span class="lineno"> 38</span>&#160; </div>
<div class="line"><a name="l00039"></a><span class="lineno"> 39</span>&#160;<span class="comment">// Cast to `const Result&amp;` from `const T&amp;` without any runtime checks.</span></div>
<div class="line"><a name="l00040"></a><span class="lineno"> 40</span>&#160;<span class="comment">// This is only valid if `sizeof(Result) == sizeof(T)`, and if `Result`, `T` are</span></div>
<div class="line"><a name="l00041"></a><span class="lineno"> 41</span>&#160;<span class="comment">// opted in as compatible via `SliceCastable`.</span></div>
<div class="line"><a name="l00042"></a><span class="lineno"> 42</span>&#160;<span class="keyword">template</span> &lt;<span class="keyword">typename</span> Result, <span class="keyword">typename</span> T&gt;</div>
<div class="line"><a name="l00043"></a><span class="lineno"><a class="line" href="namespacegrpc__event__engine_1_1experimental_1_1internal.html#ae60e17e7c4e497b7bc207fc0928fbba4"> 43</a></span>&#160;<span class="keyword">const</span> Result&amp; <a class="code" href="namespacegrpc__event__engine_1_1experimental_1_1internal.html#ae60e17e7c4e497b7bc207fc0928fbba4">SliceCast</a>(<span class="keyword">const</span> T&amp; value, <a class="code" href="structgrpc__event__engine_1_1experimental_1_1internal_1_1_slice_castable.html">SliceCastable&lt;Result, T&gt;</a> = {}) {</div>
<div class="line"><a name="l00044"></a><span class="lineno"> 44</span>&#160; <span class="comment">// Insist upon sizes being equal to catch mismatches.</span></div>
<div class="line"><a name="l00045"></a><span class="lineno"> 45</span>&#160; <span class="comment">// We assume if sizes are opted in and sizes are equal then yes, these two</span></div>
<div class="line"><a name="l00046"></a><span class="lineno"> 46</span>&#160; <span class="comment">// types are expected to be layout compatible and actually appear to be.</span></div>
<div class="line"><a name="l00047"></a><span class="lineno"> 47</span>&#160; static_assert(<span class="keyword">sizeof</span>(Result) == <span class="keyword">sizeof</span>(T), <span class="stringliteral">&quot;size mismatch&quot;</span>);</div>
<div class="line"><a name="l00048"></a><span class="lineno"> 48</span>&#160; <span class="keywordflow">return</span> <span class="keyword">reinterpret_cast&lt;</span><span class="keyword">const </span>Result&amp;<span class="keyword">&gt;</span>(value);</div>
<div class="line"><a name="l00049"></a><span class="lineno"> 49</span>&#160;}</div>
<div class="line"><a name="l00050"></a><span class="lineno"> 50</span>&#160; </div>
<div class="line"><a name="l00051"></a><span class="lineno"> 51</span>&#160;<span class="comment">// Cast to `Result&amp;` from `T&amp;` without any runtime checks.</span></div>
<div class="line"><a name="l00052"></a><span class="lineno"> 52</span>&#160;<span class="comment">// This is only valid if `sizeof(Result) == sizeof(T)`, and if `Result`, `T` are</span></div>
<div class="line"><a name="l00053"></a><span class="lineno"> 53</span>&#160;<span class="comment">// opted in as compatible via `SliceCastable`.</span></div>
<div class="line"><a name="l00054"></a><span class="lineno"> 54</span>&#160;<span class="keyword">template</span> &lt;<span class="keyword">typename</span> Result, <span class="keyword">typename</span> T&gt;</div>
<div class="line"><a name="l00055"></a><span class="lineno"><a class="line" href="namespacegrpc__event__engine_1_1experimental_1_1internal.html#aeb2de92eabb8de7bb8b2dfd3959fc52a"> 55</a></span>&#160;Result&amp; <a class="code" href="namespacegrpc__event__engine_1_1experimental_1_1internal.html#ae60e17e7c4e497b7bc207fc0928fbba4">SliceCast</a>(T&amp; value, <a class="code" href="structgrpc__event__engine_1_1experimental_1_1internal_1_1_slice_castable.html">SliceCastable&lt;Result, T&gt;</a> = {}) {</div>
<div class="line"><a name="l00056"></a><span class="lineno"> 56</span>&#160; <span class="comment">// Insist upon sizes being equal to catch mismatches.</span></div>
<div class="line"><a name="l00057"></a><span class="lineno"> 57</span>&#160; <span class="comment">// We assume if sizes are opted in and sizes are equal then yes, these two</span></div>
<div class="line"><a name="l00058"></a><span class="lineno"> 58</span>&#160; <span class="comment">// types are expected to be layout compatible and actually appear to be.</span></div>
<div class="line"><a name="l00059"></a><span class="lineno"> 59</span>&#160; static_assert(<span class="keyword">sizeof</span>(Result) == <span class="keyword">sizeof</span>(T), <span class="stringliteral">&quot;size mismatch&quot;</span>);</div>
<div class="line"><a name="l00060"></a><span class="lineno"> 60</span>&#160; <span class="keywordflow">return</span> <span class="keyword">reinterpret_cast&lt;</span>Result&amp;<span class="keyword">&gt;</span>(value);</div>
<div class="line"><a name="l00061"></a><span class="lineno"> 61</span>&#160;}</div>
<div class="line"><a name="l00062"></a><span class="lineno"> 62</span>&#160; </div>
<div class="line"><a name="l00063"></a><span class="lineno"> 63</span>&#160;} <span class="comment">// namespace internal</span></div>
<div class="line"><a name="l00064"></a><span class="lineno"> 64</span>&#160;} <span class="comment">// namespace experimental</span></div>
<div class="line"><a name="l00065"></a><span class="lineno"> 65</span>&#160;} <span class="comment">// namespace grpc_event_engine</span></div>
<div class="line"><a name="l00066"></a><span class="lineno"> 66</span>&#160; </div>
<div class="line"><a name="l00067"></a><span class="lineno"> 67</span>&#160;<span class="preprocessor">#endif // GRPC_EVENT_ENGINE_INTERNAL_SLICE_CAST_H</span></div>
</div><!-- fragment --></div><!-- contents -->
<div class="ttc" id="astructgrpc__event__engine_1_1experimental_1_1internal_1_1_slice_castable_html"><div class="ttname"><a href="structgrpc__event__engine_1_1experimental_1_1internal_1_1_slice_castable.html">grpc_event_engine::experimental::internal::SliceCastable</a></div><div class="ttdef"><b>Definition:</b> slice_cast.h:30</div></div>
<div class="ttc" id="anamespacegrpc__event__engine_html"><div class="ttname"><a href="namespacegrpc__event__engine.html">grpc_event_engine</a></div><div class="ttdef"><b>Definition:</b> endpoint_config.h:24</div></div>
<div class="ttc" id="anamespacegrpc__event__engine_1_1experimental_1_1internal_html_ae60e17e7c4e497b7bc207fc0928fbba4"><div class="ttname"><a href="namespacegrpc__event__engine_1_1experimental_1_1internal.html#ae60e17e7c4e497b7bc207fc0928fbba4">grpc_event_engine::experimental::internal::SliceCast</a></div><div class="ttdeci">const Result &amp; SliceCast(const T &amp;value, SliceCastable&lt; Result, T &gt;={})</div><div class="ttdef"><b>Definition:</b> slice_cast.h:43</div></div>
<!-- start footer part -->
<hr class="footer"/><address class="footer"><small>
Generated on Wed Sep 6 2023 16:09:16 for GRPC C++ by &#160;<a href="http://www.doxygen.org/index.html">
<img class="footer" src="doxygen.png" alt="doxygen"/>
</a> 1.8.17
</small></address>
</body>
</html>