How to get the name of a Unicode character? - c++

Question

I think I saw this a long time ago; a way to get a string containing the name of a unicode character by using Win32 API calls. I'm using C++ Builder so if there is support for it in the VCL library that would work fine too.
For example:
GetUnicodeName(U+0021) would return a string (or fill in a struct or similar), such as "EXCLAMATION MARK".
Or if there are some other way to get the same result from Windows with C or C++.
The worst case scenario would be to have a HUGE lookup table with the names of interest (mainly Latin characters).

Answer 1

You can use undocumented GetUName method from getuname.dll:
std::string GetUnicodeCharacterName(wchar_t character)
{
// https://github.com/reactos/reactos/tree/master/dll/win32/getuname
typedef int(WINAPI* GetUNameFunc)(WORD wCharCode, LPWSTR lpBuf);
static GetUNameFunc pfnGetUName = reinterpret_cast<GetUNameFunc>(::GetProcAddress(::LoadLibraryA("getuname.dll"), "GetUName"));
if (!pfnGetUName)
return {};
std::array<WCHAR, 256> buffer;
int length = pfnGetUName(character, buffer.data());
return utf8::narrow(buffer.data(), length);
}
// Replace invisible code point with code point that is visible
wchar_t ReplaceInvisible(wchar_t character)
{
if (!std::iswgraph(character))
{
if (character <= 0x21)
character += 0x2400; // U+2400 Control Pictures https://www.unicode.org/charts/PDF/U2400.pdf
else
character = 0xFFFD; // REPLACEMENT CHARACTER
}
return character;
}
// Accepts in UTF-8.
// Returns UTF-8 string like this:
// q <U+71 Latin Small Letter Q>
// п <U+43F Cyrillic Small Letter Pe>
// ␈ <U+8 Backspace>
// 𐌸 <U+10338 Supplementary Multilingual Plane>
// 🚒 <U+1F692 Supplementary Multilingual Plane>
std::string GetUnicodeCharacterNames(std::string string)
{
// UTF-8 <=> UTF-32 converter
std::wstring_convert<std::codecvt_utf8<char32_t>, char32_t> utf32conv;
// UTF-8 to UTF-32
std::u32string utf32string = utf32conv.from_bytes(string);
std::string characterNames;
characterNames.reserve(35 * utf32string.size());
for (const char32_t& codePoint : utf32string)
{
if (!characterNames.empty())
characterNames.append(", ");
char32_t visibleCodePoint = (codePoint < 0xFFFF) ? ReplaceInvisible(static_cast<wchar_t>(codePoint)) : codePoint;
std::string charName = (codePoint < 0xFFFF) ? GetUnicodeCharacterName(static_cast<wchar_t>(codePoint)) : "Supplementary Multilingual Plane";
// UTF-32 to UTF-8
std::string utf8codePoint = utf32conv.to_bytes(&visibleCodePoint, &visibleCodePoint + 1);
characterNames.append(fmt::format("{} <U+{:X} {}>", utf8codePoint, static_cast<uint32_t>(codePoint), charName));
}
return characterNames;
}
The downside is that it only contains characters from Unicode Basic Multilingual Plane (BMP).
Update: You can use u_charName() ICU API that comes with Windows since Fall Creators Update (Version 1709 Build 16299):
std::string GetUCharNameWrapper(char32_t codePoint)
{
typedef int32_t(*u_charNameFunc)(char32_t code, int nameChoice, char* buffer, int32_t bufferLength, int* pErrorCode);
static u_charNameFunc pfnU_charName = reinterpret_cast<u_charNameFunc>(::GetProcAddress(::LoadLibraryA("icuuc.dll"), "u_charName"));
if (!pfnU_charName)
return {};
int errorCode = 0;
std::array<char, 512> buffer;
int32_t length = pfnU_charName(codePoint, 0/*U_UNICODE_CHAR_NAME*/ , buffer.data(), static_cast<int32_t>(buffer.size() - 1), &errorCode);
if (errorCode != 0)
return {};
return std::string(buffer.data(), length);
}