<?xml version="1.0" encoding="UTF-8"?> <!DOCTYPE html> <html lang="en"> <head> <meta http-equiv="Content-Type" content="text/html; charset=utf-8" /> <!-- qbytearraymatcher.cpp --> <title>QStaticByteArrayMatcher Class | Qt Core 5.12.6</title> <link rel="stylesheet" type="text/css" href="style/offline-simple.css" /> <script type="text/javascript"> document.getElementsByTagName("link").item(0).setAttribute("href", "style/offline.css"); // loading style sheet breaks anchors that were jumped to before // so force jumping to anchor again setTimeout(function() { var anchor = location.hash; // need to jump to different anchor first (e.g. none) location.hash = "#"; setTimeout(function() { location.hash = anchor; }, 0); }, 0); </script> </head> <body> <div class="header" id="qtdocheader"> <div class="main"> <div class="main-rounded"> <div class="navigationbar"> <table><tr> <td >Qt 5.12</td><td ><a href="qtcore-index.html">Qt Core</a></td><td ><a href="qtcore-module.html">C++ Classes</a></td><td >QStaticByteArrayMatcher</td></tr></table><table class="buildversion"><tr> <td id="buildversion" width="100%" align="right"><a href="qtcore-index.html">Qt 5.12.6 Reference Documentation</a></td> </tr></table> </div> </div> <div class="content"> <div class="line"> <div class="content mainContent"> <div class="sidebar"> <div class="toc"> <h3><a name="toc">Contents</a></h3> <ul> <li class="level1"><a href="#public-functions">Public Functions</a></li> <li class="level1"><a href="#related-non-members">Related Non-Members</a></li> <li class="level1"><a href="#details">Detailed Description</a></li> </ul> </div> <div class="sidebar-content" id="sidebar-content"></div></div> <h1 class="title">QStaticByteArrayMatcher Class</h1> <!-- $$$QStaticByteArrayMatcher-brief --> <p>The <a href="qstaticbytearraymatcher.html">QStaticByteArrayMatcher</a> class is a compile-time version of <a href="qbytearraymatcher.html">QByteArrayMatcher</a>. <a href="#details">More...</a></p> <!-- @@@QStaticByteArrayMatcher --> <div class="table"><table class="alignedsummary"> <tr><td class="memItemLeft rightAlign topAlign"> Header:</td><td class="memItemRight bottomAlign"> <span class="preprocessor">#include <QStaticByteArrayMatcher></span> </td></tr><tr><td class="memItemLeft rightAlign topAlign"> qmake:</td><td class="memItemRight bottomAlign"> QT += core</td></tr><tr><td class="memItemLeft rightAlign topAlign"> Since:</td><td class="memItemRight bottomAlign"> Qt 5.9</td></tr></table></div><ul> <li><a href="qstaticbytearraymatcher-members.html">List of all members, including inherited members</a></li> </ul> <a name="public-functions"></a> <h2 id="public-functions">Public Functions</h2> <div class="table"><table class="alignedsummary"> <tr><td class="memItemLeft rightAlign topAlign"> int </td><td class="memItemRight bottomAlign"><b><a href="qstaticbytearraymatcher.html#indexIn">indexIn</a></b>(const QByteArray &<i>haystack</i>, int <i>from</i> = ...) const</td></tr> <tr><td class="memItemLeft rightAlign topAlign"> int </td><td class="memItemRight bottomAlign"><b><a href="qstaticbytearraymatcher.html#indexIn-1">indexIn</a></b>(const char *<i>haystack</i>, int <i>hlen</i>, int <i>from</i> = ...) const</td></tr> <tr><td class="memItemLeft rightAlign topAlign"> QByteArray </td><td class="memItemRight bottomAlign"><b><a href="qstaticbytearraymatcher.html#pattern">pattern</a></b>() const</td></tr> </table></div> <a name="related-non-members"></a> <h2 id="related-non-members">Related Non-Members</h2> <div class="table"><table class="alignedsummary"> <tr><td class="memItemLeft rightAlign topAlign"> QStaticByteArrayMatcher<N> </td><td class="memItemRight bottomAlign"><b><a href="qstaticbytearraymatcher.html#qMakeStaticByteArrayMatcher">qMakeStaticByteArrayMatcher</a></b>(const char (&)[N] <i>pattern</i> = N)</td></tr> </table></div> <a name="details"></a> <!-- $$$QStaticByteArrayMatcher-description --> <div class="descr"> <h2 id="details">Detailed Description</h2> <p>The <a href="qstaticbytearraymatcher.html">QStaticByteArrayMatcher</a> class is a compile-time version of <a href="qbytearraymatcher.html">QByteArrayMatcher</a>.</p> <p>This class is useful when you have a sequence of bytes that you want to repeatedly match against some byte arrays (perhaps in a loop), or when you want to search for the same sequence of bytes multiple times in the same byte array. Using a matcher object and <a href="qstaticbytearraymatcher.html#indexIn">indexIn</a>() is faster than matching a plain <a href="qbytearray.html">QByteArray</a> with <a href="qbytearray.html#indexOf">QByteArray::indexOf</a>(), in particular if repeated matching takes place.</p> <p>Unlike <a href="qbytearraymatcher.html">QByteArrayMatcher</a>, this class calculates the internal representation at <i>compile-time</i>, if your compiler supports C++14-level <code>constexpr</code> (C++11 is not sufficient), so it can even benefit if you are doing one-off byte array matches.</p> <p>Create the <a href="qstaticbytearraymatcher.html">QStaticByteArrayMatcher</a> by calling <a href="qstaticbytearraymatcher.html#qMakeStaticByteArrayMatcher">qMakeStaticByteArrayMatcher</a>(), passing it the C string literal you want to search for. Store the return value of that function in a <code>static const auto</code> variable, so you don't need to pass the <code>N</code> template parameter explicitly:</p> <pre class="cpp"> <span class="keyword">static</span> <span class="keyword">const</span> <span class="keyword">auto</span> matcher <span class="operator">=</span> <a href="qstaticbytearraymatcher.html#qMakeStaticByteArrayMatcher">qMakeStaticByteArrayMatcher</a>(<span class="string">"needle"</span>); </pre> <p>Then call <a href="qstaticbytearraymatcher.html#indexIn">indexIn</a>() on the <a href="qbytearray.html">QByteArray</a> in which you want to search, just like with <a href="qbytearraymatcher.html">QByteArrayMatcher</a>.</p> <p>Since this class is designed to do all the up-front calculations at compile-time, it does not offer a setPattern() method.</p> <p><b>Note: </b>Qt detects the necessary C++14 compiler support by way of the feature test recommendations from <a href="https://isocpp.org/std/standing-documents/sd-6-sg10-feature-test-recommendations">C++ Committee's Standing Document 6</a>.</p></div> <p><b>See also </b><a href="qbytearraymatcher.html">QByteArrayMatcher</a> and <a href="qstringmatcher.html">QStringMatcher</a>.</p> <!-- @@@QStaticByteArrayMatcher --> <div class="func"> <h2>Member Function Documentation</h2> <!-- $$$indexIn[overload1]$$$indexInconstQByteArray&int --> <h3 class="fn" id="indexIn"><a name="indexIn"></a><span class="type">int</span> QStaticByteArrayMatcher::<span class="name">indexIn</span>(const <span class="type"><a href="qbytearray.html">QByteArray</a></span> &<i>haystack</i>, <span class="type">int</span> <i>from</i> = ...) const</h3> <p>Searches the char string <i>haystack</i>, from byte position <i>from</i> (default 0, i.e. from the first byte), for the byte array <a href="qstaticbytearraymatcher.html#pattern">pattern</a>() that was set in the constructor.</p> <p>Returns the position where the <a href="qstaticbytearraymatcher.html#pattern">pattern</a>() matched in <i>haystack</i>, or -1 if no match was found.</p> <!-- @@@indexIn --> <!-- $$$indexIn$$$indexInconstchar*intint --> <h3 class="fn" id="indexIn-1"><a name="indexIn-1"></a><span class="type">int</span> QStaticByteArrayMatcher::<span class="name">indexIn</span>(const <span class="type">char</span> *<i>haystack</i>, <span class="type">int</span> <i>hlen</i>, <span class="type">int</span> <i>from</i> = ...) const</h3> <p>Searches the char string <i>haystack</i>, which has length <i>hlen</i>, from byte position <i>from</i> (default 0, i.e. from the first byte), for the byte array <a href="qstaticbytearraymatcher.html#pattern">pattern</a>() that was set in the constructor.</p> <p>Returns the position where the <a href="qstaticbytearraymatcher.html#pattern">pattern</a>() matched in <i>haystack</i>, or -1 if no match was found.</p> <!-- @@@indexIn --> <!-- $$$pattern[overload1]$$$pattern --> <h3 class="fn" id="pattern"><a name="pattern"></a><span class="type"><a href="qbytearray.html">QByteArray</a></span> QStaticByteArrayMatcher::<span class="name">pattern</span>() const</h3> <p>Returns the byte array pattern that this byte array matcher will search for.</p> <p><b>See also </b><a href="qbytearraymatcher.html#setPattern">QByteArrayMatcher::setPattern</a>().</p> <!-- @@@pattern --> </div> <div class="relnonmem"> <h2>Related Non-Members</h2> <!-- $$$qMakeStaticByteArrayMatcher[overload1]$$$qMakeStaticByteArrayMatcherconstchar(&)[N] --> <h3 class="fn" id="qMakeStaticByteArrayMatcher"><a name="qMakeStaticByteArrayMatcher"></a><span class="type">QStaticByteArrayMatcher</span><<span class="type">N</span>> <span class="name">qMakeStaticByteArrayMatcher</span>(const <span class="type">char</span> (&)[<span class="type">N</span>] <i>pattern</i> = N)</h3> <p>Return a <a href="qstaticbytearraymatcher.html">QStaticByteArrayMatcher</a> with the correct <code>N</code> determined automatically from the <i>pattern</i> passed.</p> <p>To take full advantage of this function, assign the result to an <code>auto</code> variable:</p> <pre class="cpp"> <span class="keyword">static</span> <span class="keyword">const</span> <span class="keyword">auto</span> matcher <span class="operator">=</span> qMakeStaticByteArrayMatcher(<span class="string">"needle"</span>); </pre> <p>This function was introduced in Qt 5.9.</p> <!-- @@@qMakeStaticByteArrayMatcher --> </div> </div> </div> </div> </div> </div> <div class="footer"> <p> <acronym title="Copyright">©</acronym> 2019 The Qt Company Ltd. Documentation contributions included herein are the copyrights of their respective owners.<br/> The documentation provided herein is licensed under the terms of the <a href="http://www.gnu.org/licenses/fdl.html">GNU Free Documentation License version 1.3</a> as published by the Free Software Foundation.<br/> Qt and respective logos are trademarks of The Qt Company Ltd. in Finland and/or other countries worldwide. All other trademarks are property of their respective owners. </p> </div> </body> </html>