Function utf16_from_utf8

src/cpp/web-ifc/parsing/string_parsing.cpp:17–50

	std::u16string utf16_from_utf8(const std::string& utf8) {
		std::u16string utf16;
		size_t i = 0;

		while (i < utf8.size()) {
			char16_t ch = 0;
			unsigned char byte = utf8[i];

			if (byte < 0x80) {
				// 1-byte character (ASCII)
				ch = byte;
				i += 1;
			}
			else if ((byte & 0xE0) == 0xC0) {
				// 2-byte character
				if (i + 1 >= utf8.size()) throw std::runtime_error("Invalid UTF-8 sequence");
				ch = ((byte & 0x1F) << 6) | (utf8[i + 1] & 0x3F);
				i += 2;
			}
			else if ((byte & 0xF0) == 0xE0) {
				// 3-byte character
				if (i + 2 >= utf8.size()) throw std::runtime_error("Invalid UTF-8 sequence");
				ch = ((byte & 0x0F) << 12) | ((utf8[i + 1] & 0x3F) << 6) | (utf8[i + 2] & 0x3F);
				i += 3;
			}
			else {
				throw std::runtime_error("Unsupported UTF-8 sequence");
			}

			utf16.push_back(ch);
		}

		return utf16;
	}

    void encodeCharacters(std::ostringstream &stream,std::string &data) 
    {