Giovanni Dicanio
This C++ project contains a reusable header-only module implementing conversion code between UTF-8 (std::string) and UTF-16 (CStringW).
It makes sense to use ATL CStringW in portions of C++ code at the Windows ATL/MFC level for UTF-16 text;
on the other hand, STL std::string makes sense e.g. in cross-platform C++ code, storing UTF-8 text.
This reusable header-only module (Utf8Conv.h)
provides convenient conversion functions between these two Unicode encodings.
Conversion errors are signaled throwing instances of a custom exception class.
For more details, please read my MSDN Magazine article:
C++ - Unicode Encoding Conversions with STL Strings and Win32 APIs
The code presented here is based on that article, but uses CStringW instead
of std::wstring for UTF-16 strings at the Windows platform level.
In addition, it's also possible to pass input source strings using an STL-style [start, finish) range; this is useful for converting portions, or views, of source strings.
This project contains also a unit-test (Utf8ConvTest.cpp) for the reusable Unicode conversion module.
Code developed using Visual Studio 2015.
Compiles cleanly at /W4 in both 32-bit builds and 64-bit builds.
Note for Older VC++ Compilers
If you are using Visual Studio 2010, which doesn't support the C++11 constexpr keyword, you can still include this C++ code in your projects, simply substituting every instance of constexpr with const; this code will work just fine.