Core/Uuid: Add FromString builder method

src/Nazara/Core/Uuid.cpp

@@ -15,51 +15,101 @@
 
 namespace Nz
 {
+	namespace
+	{
+		bool ParseHexadecimalPair(Pointer<const char>& str, UInt8& number)
+		{
+			number = 0;
+
+			for (UInt8 mul : { 0x10, 1 })
+			{
+				if (*str >= '0' && *str <= '9')
+					number += (*str - '0') * mul;
+				else if (((*str & 0x5F) >= 'A' && (*str & 0x5F) <= 'F'))
+					number += ((*str & 0x5F) - 'A' + 10) * mul;
+				else
+					return false;
+
+				str++;
+			}
+
+			return true;
+		}
+	}
+
 	std::array<char, 37> Uuid::ToStringArray() const
 	{
-		std::array<char, 37> guidStr; //< Including \0
-		std::snprintf(guidStr.data(), guidStr.size(), "%02x%02x%02x%02x-%02x%02x-%02x%02x-%02x%02x-%02x%02x%02x%02x%02x%02x",
-		              m_guid[0], m_guid[1], m_guid[2], m_guid[3], m_guid[4], m_guid[5], m_guid[6], m_guid[7],
-		              m_guid[8], m_guid[9], m_guid[10], m_guid[11], m_guid[12], m_guid[13], m_guid[14], m_guid[15]);
+		std::array<char, 37> uuidStr; //< Including \0
+		std::snprintf(uuidStr.data(), uuidStr.size(), "%02x%02x%02x%02x-%02x%02x-%02x%02x-%02x%02x-%02x%02x%02x%02x%02x%02x",
+		              m_uuid[0], m_uuid[1], m_uuid[2], m_uuid[3], m_uuid[4], m_uuid[5], m_uuid[6], m_uuid[7],
+		              m_uuid[8], m_uuid[9], m_uuid[10], m_uuid[11], m_uuid[12], m_uuid[13], m_uuid[14], m_uuid[15]);
 
-		return guidStr;
+		return uuidStr;
+	}
+
+	Uuid Uuid::FromString(std::string_view str)
+	{
+		if (str.size() != 36)
+			return {};
+
+		const char* ptr = str.data();
+
+		std::array<UInt8, 16> uuid;
+		UInt8* uuidPart = &uuid[0];
+
+		bool first = true;
+		for (std::size_t groupSize : { 4, 2, 2, 2, 6 })
+		{
+			if (!first && *ptr++ != '-')
+				return {};
+
+			first = false;
+
+			for (std::size_t i = 0; i < groupSize; ++i)
+			{
+				if (!ParseHexadecimalPair(ptr, *uuidPart++))
+					return {};
+			}
+		}
+
+		return Uuid{ uuid };
 	}
 
 	Uuid Uuid::Generate()
 	{
-		std::array<UInt8, 16> guid;
+		std::array<UInt8, 16> uuid;
 
 #ifdef NAZARA_PLATFORM_WINDOWS
 		GUID id;
 		CoCreateGuid(&id);
 
 		for (unsigned int i = 0; i < 4; ++i)
-			guid[i] = static_cast<UInt8>(id.Data1 >> ((3 - i) * 8 & 0xFF));
+			uuid[i] = static_cast<UInt8>(id.Data1 >> ((3 - i) * 8 & 0xFF));
 
 		for (unsigned int i = 0; i < 2; ++i)
-			guid[4 + i] = static_cast<UInt8>(id.Data2 >> ((1 - i) * 8 & 0xFF));
+			uuid[4 + i] = static_cast<UInt8>(id.Data2 >> ((1 - i) * 8 & 0xFF));
 
 		for (unsigned int i = 0; i < 2; ++i)
-			guid[6 + i] = static_cast<UInt8>(id.Data3 >> ((1 - i) * 8 & 0xFF));
+			uuid[6 + i] = static_cast<UInt8>(id.Data3 >> ((1 - i) * 8 & 0xFF));
 
 		for (unsigned int i = 0; i < 8; ++i)
-			guid[8 + i] = static_cast<UInt8>(id.Data4[i]);
+			uuid[8 + i] = static_cast<UInt8>(id.Data4[i]);
 #elif defined(NAZARA_PLATFORM_LINUX) || defined(NAZARA_PLATFORM_MACOSX)
 		uuid_t id;
 		uuid_generate(id);
 
-		std::copy(std::begin(id), std::end(id), guid.begin());
+		std::copy(std::begin(id), std::end(id), uuid.begin());
 #else
 #error Missing platform support
 #endif
 
-		return guid;
+		return uuid;
 	}
 
 	std::ostream& operator<<(std::ostream& out, const Uuid& guid)
 	{
-		std::array<char, 37> guidStr = guid.ToStringArray();
+		std::array<char, 37> uuidStr = guid.ToStringArray();
 
-		return out << guidStr.data();
+		return out << uuidStr.data();
 	}
 }