added functions for target immunity testing

--HG--
extra : convert_revision : svn%3A39bc706e-5318-0410-9160-8a85361fbb7c/trunk%40546

plugins/include/admin.inc

@@ -462,12 +462,33 @@ native FlagArrayToBits(const AdminFlag:array[], numFlags) =0;
  */
 native FlagBitsToArray(bits, AdminFlag:array[], maxSize) =0;
 
+/**
+ * Tests whether one admin can target another.
+ *
+ * @param admin			Admin doing the targetting (may be INVALID_ADMIN_ID).
+ * @param target		Target admin (may be INVALID_ADMIN_ID).
+ * @return				True if targetable, false if immune.
+ */
+native CanAdminTarget(AdminId:admin, AdminId:target);
 
+/**
+ * Converts a flag to its single bit.
+ * 
+ * @param flag			Flag to convert.
+ * @return				Bit representation of the flag.
+ */
 stock FlagToBit(AdminFlag:flag)
 {
 	return (1<<_:flag);
 }
 
+/**
+ * Converts a bit to an AdminFlag.
+ *
+ * @param bit			Bit to convert.
+ * @param flag			Stores the converted flag by reference.
+ * @return				True on success, false otherwise.
+ */
 stock bool:BitToFlag(bit, &AdminFlag:flag)
 {
 	new AdminFlag:array[1];

plugins/include/sourcemod.inc

@@ -328,6 +328,17 @@ native SetUserFlagBits(client, flags);
  */
 native GetUserFlagBits(client);
 
+/**
+ * Returns whether a user can target another user.
+ * This is a helper function for CanAdminTarget.
+ *
+ * @param client		Player's index.
+ * @param target		Target player's index.
+ * @return				True if target is targettable by the player, false otherwise.
+ * @error				Invalid or unconnected player indexers.
+ */
+native bool:CanUserTarget(client, target);
+
 /**
  * Logs a generic message to the HL2 logs.
  *