Repeat is a function template to abstract and simplify loops that repeat N times, from Vittorio Romeo. The C++ range based for doesn't directly allow N repetitions of code. Vittorio's utility fills that gap. Vittorio's blog article is here.
A common mistake in C++ is to forget to call std::erase after calling std::remove. This utility wraps the two together allowing either a value to be directly removed from a container, or a set of values to be removed using a predicate. This utility code is copied from a StackOverflow post by Richard Hodges (see References).
Since std::byte pointers are used as a general buffer interface, a small utility function from Blitz Rakete as posted on Stackoverflow (see References) is useful to simplify creation of byte buffers, specially for testing purposes. In addition, a utility function to compare @c std::byte arrays is provided.
Note: This utility is mostly or completely outdated due to the C++ 20 std::bit_cast function.
Using reinterpret_cast in C++ may mean undefined (even if well understood and executionally correct) behavior. In networking and other types of I/O processing it is a common need to convert a pointer to a char *, or in C++ 17 (and later) a std::byte *.
The cast_ptr_to utility conveniently combines a static cast to void * with a static cast to a specified (via function template parameter) type. Typically the destination type is a std::byte pointer.
If the destination type is unrelated to the original type (and is not a void * or some form of char * such as std::byte *) undefined behavior will still occur. However, if converting the pointer to a std::byte pointer and then back to the original pointer type, the behavior is well defined and safe.
This utility creates a class providing a set of function object overloads (operator()) from a parameter pack. There is both a class template and a function template. This utility is specially useful when calling std::visit, allowing a set of lambdas to be created corresponding to the visitation set for a std::variant. The code is directly copied from C++ Reference.
Capturing perfectly forwarded references in a lambda is difficult. (Forwarding references are also called universal references, a term coined by Scott Meyers.) This utility eases the task with a level of indirection. The design and code come from Vittorio Romeo's blog article.