Qt 5.9 | Qt Core | C++ Classes | QStaticByteArrayMatcher

Qt 5.9.9 Reference Documentation

# QStaticByteArrayMatcher Class

The QStaticByteArrayMatcher class is a compile-time version of QByteArrayMatcher More...

Header: | #include <QStaticByteArrayMatcher>
qmake: | QT += core
Since: | Qt 5.9

## Detailed Description

The QStaticByteArrayMatcher class is a compile-time version of QByteArrayMatcher

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 indexIn() is faster than matching a plain QByteArray with QByteArray::indexOf(), in particular if repeated matching takes place.

Unlike QByteArrayMatcher, this class calculates the internal representation at compile-time, if your compiler supports C++14-level `constexpr` (C++11 is not sufficient), so it can even benefit if you are doing one-off byte array matches.

Create the QStaticByteArrayMatcher by calling qMakeStaticByteArrayMatcher(), passing it the C string literal you want to search for. Store the return value of that function in a `static const auto` variable, so you don't need to pass the `N` template parameter explicitly:

      static const auto matcher = qMakeStaticByteArrayMatcher("needle");

Then call indexIn() on the QByteArray in which you want to search, just like with QByteArrayMatcher.

Since this class is designed to do all the up-front calculations at compile-time, it does not offer a setPattern() method.

See also QByteArrayMatcher and QStringMatcher.