Header-only parsing and formatting of file sizes

Small utility header for human-formatted input and output of file sizes in bytes:

5.55k, 5.55 k, 5.55kB, 5.55 kiB to number of bytes
available case-sensitive prefixes are k, M, G, T, P (decimal) and ki, Mi, Gi, Ti, Pi (binary)
throws exceptions for invalid inputs
formats to 3-digit precision with affixed decimal units (e.g. 5.55 kB)
defined operator<< for iostream output
defines c++ literals in bytesize::literals namespace

How to use

to parse a std::string, use bytesize::bytesize::parse static method
to output, use bytesize::bytesize::format
output to std::ostream via operator<<
output to fmt with {} automatically — use BYTESIZE_FMTLIB_FORMATTER to declare the tempate (fmt/fmt.h must be included before that)
using namespace bytesize::literals to do things like 5.55_kB in your source