Function get_valid_length

lib/pugixml/src/pugixml.cpp:3606–3612

#ifdef PUGIXML_WCHAR_MODE
	PUGI__FN size_t get_valid_length(const char_t* data, size_t length)
	{
		if (length < 1) return 0;

		// discard last character if it's the lead of a surrogate pair
		return (sizeof(wchar_t) == 2 && static_cast<unsigned int>(static_cast<uint16_t>(data[length - 1]) - 0xD800) < 0x400) ? length - 1 : length;
	}

	PUGI__FN size_t convert_buffer_output(char_t* r_char, uint8_t* r_u8, uint16_t* r_u16, uint32_t* r_u32, const char_t* data, size_t length, xml_encoding encoding)
	{