2 files changed, 38 insertions, 2 deletions

diff --git a/src/ClientHandle.cpp b/src/ClientHandle.cpp
index ade7e20ac..46083a8f1 100644
--- a/src/ClientHandle.cpp
+++ b/src/ClientHandle.cpp
@@ -232,6 +232,9 @@ AString cClientHandle::FormatMessageType(bool ShouldAppendChatPrefixes, eMessage
 
 AString cClientHandle::GenerateOfflineUUID(const AString & a_Username)
 {
+	// Online UUIDs are always version 4 (random)
+	// We use Version 3 (MD5 hash) UUIDs for the offline UUIDs
+	// This guarantees that they will never collide with an online UUID and can be distinguished.
 	// Proper format for a version 3 UUID is:
 	// xxxxxxxx-xxxx-3xxx-yxxx-xxxxxxxxxxxx where x is any hexadecimal digit and y is one of 8, 9, A, or B
 	
@@ -254,6 +257,32 @@ AString cClientHandle::GenerateOfflineUUID(const AString & a_Username)
 
 
 
+bool cClientHandle::IsUUIDOnline(const AString & a_UUID)
+{
+	// Online UUIDs are always version 4 (random)
+	// We use Version 3 (MD5 hash) UUIDs for the offline UUIDs
+	// This guarantees that they will never collide with an online UUID and can be distinguished.
+	// The version-specifying char is at pos #12 of raw UUID, pos #14 in dashed-UUID.
+	switch (a_UUID.size())
+	{
+		case 32:
+		{
+			// This is the UUID format without dashes, the version char is at pos #12:
+			return (a_UUID[12] == '4');
+		}
+		case 36:
+		{
+			// This is the UUID format with dashes, the version char is at pos #14:
+			return (a_UUID[14] == '4');
+		}
+	}
+	return false;
+}
+
+
+
+
+
 void cClientHandle::Kick(const AString & a_Reason)
 {
 	if (m_State >= csAuthenticating)  // Don't log pings
diff --git a/src/ClientHandle.h b/src/ClientHandle.h
index 0d883f3af..3e18cbdad 100644
--- a/src/ClientHandle.h
+++ b/src/ClientHandle.h
@@ -63,7 +63,7 @@ public:
 
 	const AString & GetIPString(void) const { return m_IPString; }
 	
-	cPlayer* GetPlayer() { return m_Player; }	// tolua_export
+	cPlayer * GetPlayer(void) { return m_Player; }	// tolua_export
 
 	const AString & GetUUID(void) const { return m_UUID; } // tolua_export
 	void SetUUID(const AString & a_UUID) { m_UUID = a_UUID; }
@@ -76,9 +76,16 @@ public:
 	
 	/** Generates an UUID based on the player name provided.
 	This is used for the offline (non-auth) mode, when there's no UUID source.
-	Each username generates a unique and constant UUID, so that when the player reconnects with the same name, their UUID is the same. */
+	Each username generates a unique and constant UUID, so that when the player reconnects with the same name, their UUID is the same.
+	Returns a 36-char UUID (with dashes). */
 	static AString GenerateOfflineUUID(const AString & a_Username);  // tolua_export
 	
+	/** Returns true if the UUID is generated by online auth, false if it is an offline-generated UUID.
+	We use Version-3 UUIDs for offline UUIDs, online UUIDs are Version-4, thus we can tell them apart.
+	Accepts both 32-char and 36-char UUIDs (with and without dashes).
+	If the string given is not a valid UUID, returns false. */
+	static bool IsUUIDOnline(const AString & a_UUID);  // tolua_export
+	
 	/** Formats the type of message with the proper color and prefix for sending to the client. **/
 	static AString FormatMessageType(bool ShouldAppendChatPrefixes, eMessageType a_ChatPrefix, const AString & a_AdditionalData);