performance

[chipsethan]

Tested with a 126MB UTF-8 format text file against ww898's [https://github.com/ww898/utf-cpp] Testing source code here: https://github.com/chipsethan/UTF-test.git It seems yours has a little room to improve. I hope you can optimize your code some day.

Visual Studio 2019 - 16.10.0 (Win10 Pro 20H2, x64, Intel i7-8700)

Mikhail Pilin (2.3) UTF8-->UTF32:584.876ms UTF8-->UTF16:417.439ms UTF32-->UTF8:311.549ms UTF16-->UTF8:276.505ms

Nemanja Trifunovic (3.2.1) UTF8-->UTF32:1081.22ms UTF8-->UTF16:950.651ms UTF32-->UTF8:309.367ms UTF16-->UTF8:476.447ms identical results, ok

g++ 10.3.0 - msys2 (Win10 Pro 20H2, x64, Intel i7-8700)

Mikhail Pilin (2.3) UTF8-->UTF32:334.683ms UTF8-->UTF16:256.315ms UTF32-->UTF8:240.74ms UTF16-->UTF8:323.077ms

Nemanja Trifunovic (3.2.1) UTF8-->UTF32:371.187ms UTF8-->UTF16:253.828ms UTF32-->UTF8:429.623ms UTF16-->UTF8:467.776ms identical results, ok