How to search substring in QLatin1String?

Question

What is the reason that QLatin1String class has not any operations for searching substring in it, such as indexOf, find or contains? Only startsWith and endsWith I was found, but they can't search in the middle of the string

Answer 1

As to why, you'd have to take that up with Qt.

Generally speaking QLatin1String is used to indicate what we used to call ASCII text (no Unicode). QString is the default, all-powerful string in Qt, and you should generally use that, or you could convert it to a std::string and use that. Either of these may come at the cost of a copy.

If you want to avoid the copy, QLatin1String does have begin() and end() functions, so you can use standard algorithms on it too, like C++17's new std::search():

auto s = QLatin1String("The lazy dog");
auto needle = QLatin1String("azy");
auto it = std::search( std::begin(s), std::end(s), 
    std::boyer_moore_horspool_searcher( std::begin(needle), std::end(needle) ) );

Here's a working sample using std::strings that will also work for QLatin1Strings on Coliru.

See more on Bartek's coding blog.