StringFromUCS4

String^ StringFromUCS4(const char32_t* element, int length)
{
    StringBuilder^ result = gcnew StringBuilder(length);
    const char32_t* pUCS4 = element;

    int characterCount = 0;
    while (*pUCS4 != 0)
    {
        wchar_t cUTF16;
        if (*pUCS4 < 0x10000)
        {
            cUTF16 = (wchar_t)*pUCS4;
        }
        else 
        {
            unsigned int t = *pUCS4 - 0x10000;
            unsigned int h = (((t << 12) >> 22) + 0xD800);
            unsigned int l = (((t << 22) >> 22) + 0xDC00);
            cUTF16 = (wchar_t)((h << 16) | (l & 0x0000FFFF));
        }

        result->Append((wchar_t)*pUCS4);

        characterCount++;
        if (characterCount >= length)
        {
            break;
        }

        pUCS4++;
    }

    return result->ToString();
}

来源：oschina

链接：https://my.oschina.net/u/4000302/blog/4335490