I want to iterate each character of a Unicode string, treating each surrogate pair and combining character sequence as a single unit (one grapheme).

Example

The text "??????" is comprised of the code points: U+0928, U+092E, U+0938, U+094D, U+0924, U+0947, of which, U+0938 and U+0947 are combining marks.

static void Main(string[] args)
{
    const string s = "??????";

    Console.WriteLine(s.Length); // Ouptuts "6"

    var l = 0;
    var e = System.Globalization.StringInfo.GetTextElementEnumerator(s);
    while(e.MoveNext()) l++;
    Console.WriteLine(l); // Outputs "4"
}

So there we have it in .NET. We also have Win32's CharNextW()

#include <Windows.h>
#include <iostream>
#include <string>

int main()
{
    const wchar_t * s = L"??????";

    std::cout << std::wstring(s).length() << std::endl; // Gives "6"

    int l = 0;
    while(CharNextW(s) != s)
    {
        s = CharNextW(s);
        ++l;
    }

    std::cout << l << std::endl; // Gives "4"

    return 0;
}

Question

Both ways I know of are specific to Microsoft. Are there portable ways to do it?

• I heard about ICU but I couldn't find something related quickly (UnicodeString(s).length() still gives 6). Would be an acceptable answer to point to the related function/module in ICU.
• C++ doesn't have a notion of Unicode, so a lightweight cross-platform library for dealing with these issues would make an acceptable answer.