Truncate game state CRC sent over net to 16 bits.

This should save a tiny bit of bandwidth, at least 20 bytes/second.
Warzone2100 · Apr 29, 2012 · 0499825 · 0499825
1 parent 5e3d4bc
commit 0499825
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Showing 5 changed files with 15 additions and 45 deletions.
diff --git a/lib/gamelib/gtime.cpp b/lib/gamelib/gtime.cpp
@@ -216,8 +216,8 @@ void gameTimeUpdate(bool mayUpdate)
 		updateLatency();
 		if (crcError)
 		{
-			debug(LOG_ERROR, "Synch error, gameTimes were: {%s}", listToString("%10u", ", ", gameQueueCheckTime, gameQueueCheckTime + game.maxPlayers).c_str());
-			debug(LOG_ERROR, "Synch error, CRCs were:      {%s}", listToString("0x%08X", ", ", gameQueueCheckCrc, gameQueueCheckCrc + game.maxPlayers).c_str());
+			debug(LOG_ERROR, "Synch error, gameTimes were: {%s}", listToString("%7u", ", ", gameQueueCheckTime, gameQueueCheckTime + game.maxPlayers).c_str());
+			debug(LOG_ERROR, "Synch error, CRCs were:      {%s}", listToString(" 0x%04X", ", ", gameQueueCheckCrc, gameQueueCheckCrc + game.maxPlayers).c_str());
 			crcError = false;
 		}
 	}
@@ -362,7 +362,7 @@ void sendPlayerGameTime()
 	unsigned player;
 	uint32_t latencyTicks = discreteChosenLatency / GAME_TICKS_PER_UPDATE;
 	uint32_t checkTime = gameTime;
-	uint32_t checkCrc = nextDebugSync();
+	GameCrcType checkCrc = nextDebugSync();
 
 	for (player = 0; player < game.maxPlayers; ++player)
 	{
@@ -374,7 +374,7 @@ void sendPlayerGameTime()
 		NETbeginEncode(NETgameQueue(player), GAME_GAME_TIME);
 			NETuint32_t(&latencyTicks);
 			NETuint32_t(&checkTime);
-			NETuint32_tLarge(&checkCrc);
+			NETuint16_t(&checkCrc);
 			NETuint16_t(&wantedLatency);
 		NETend();
 	}
@@ -384,12 +384,12 @@ void recvPlayerGameTime(NETQUEUE queue)
 {
 	uint32_t latencyTicks = 0;
 	uint32_t checkTime = 0;
-	uint32_t checkCrc = 0;
+	GameCrcType checkCrc = 0;
 
 	NETbeginDecode(queue, GAME_GAME_TIME);
 		NETuint32_t(&latencyTicks);
 		NETuint32_t(&checkTime);
-		NETuint32_tLarge(&checkCrc);
+		NETuint16_t(&checkCrc);
 		NETuint16_t(&wantedLatencies[queue.index]);
 	NETend();
 

diff --git a/lib/netplay/netplay.cpp b/lib/netplay/netplay.cpp
@@ -3398,7 +3398,7 @@ void resetSyncDebug()
 	syncDebugNumDumps = 0;
 }
 
-uint32_t nextDebugSync(void)
+GameCrcType nextDebugSync()
 {
 	uint32_t ret = syncDebugLog[syncDebugNext].getCrc();
 
@@ -3409,7 +3409,7 @@ uint32_t nextDebugSync(void)
 	syncDebugNext = (syncDebugNext + 1)%MAX_SYNC_HISTORY;
 	syncDebugLog[syncDebugNext].clear();
 
-	return ret;
+	return (GameCrcType)ret;
 }
 
 static void dumpDebugSync(uint8_t *buf, size_t bufLen, uint32_t time, unsigned player)
@@ -3453,7 +3453,7 @@ static void recvDebugSync(NETQUEUE queue)
 	dumpDebugSync(debugSyncTmpBuf, bufLen, time, queue.index);
 }
 
-bool checkDebugSync(uint32_t checkGameTime, uint32_t checkCrc)
+bool checkDebugSync(uint32_t checkGameTime, GameCrcType checkCrc)
 {
 	if (checkGameTime == syncDebugLog[syncDebugNext].getGameTime())  // Can't happen - and syncDebugGameTime[] == 0, until just before sending the CRC, anyway.
 	{
@@ -3466,7 +3466,7 @@ bool checkDebugSync(uint32_t checkGameTime, uint32_t checkCrc)
 	{
 		if (syncDebugLog[logIndex].getGameTime() == checkGameTime)
 		{
-			if (syncDebugLog[logIndex].getCrc() == checkCrc)  // Invert bits, since everyone else seems to do that with CRCs...
+			if ((GameCrcType)syncDebugLog[logIndex].getCrc() == checkCrc)
 			{
 				return true;                    // Check passed. (So far... There might still be more players to compare CRCs with.)
 			}
@@ -3477,7 +3477,7 @@ bool checkDebugSync(uint32_t checkGameTime, uint32_t checkCrc)
 
 	if (logIndex >= MAX_SYNC_HISTORY && syncDebugExtraGameTime == checkGameTime)
 	{
-		if (syncDebugExtraCrc == checkCrc)
+		if ((GameCrcType)syncDebugExtraCrc == checkCrc)
 		{
 			return true;
 		}

diff --git a/lib/netplay/netplay.h b/lib/netplay/netplay.h
@@ -352,8 +352,9 @@ void _syncDebugIntList(const char *function, const char *str, int *ints, size_t
 #define syncDebugBacktrace() do { _syncDebugBacktrace(__FUNCTION__); } while(0)
 void _syncDebugBacktrace(const char *function);                  ///< Adds a backtrace to syncDebug, if the platform supports it. Can be a bit slow, don't call way too often, unless desperate.
 
-void resetSyncDebug(void);                                       ///< Resets the syncDebug, so syncDebug from a previous game doesn't cause a spurious desynch dump.
-uint32_t nextDebugSync(void);                                    ///< Returns a CRC corresponding to all syncDebug() calls since the last nextDebugSync() or resetSyncDebug() call.
-bool checkDebugSync(uint32_t checkGameTime, uint32_t checkCrc);  ///< Dumps all syncDebug() calls from that gameTime, if the CRC doesn't match.
+typedef uint16_t GameCrcType;  // Truncate CRC of game state to 16 bits, to save a bit of bandwidth.
+void resetSyncDebug();                                              ///< Resets the syncDebug, so syncDebug from a previous game doesn't cause a spurious desynch dump.
+GameCrcType nextDebugSync();                                        ///< Returns a CRC corresponding to all syncDebug() calls since the last nextDebugSync() or resetSyncDebug() call.
+bool checkDebugSync(uint32_t checkGameTime, GameCrcType checkCrc);  ///< Dumps all syncDebug() calls from that gameTime, if the CRC doesn't match.
 
 #endif
diff --git a/lib/netplay/nettypes.cpp b/lib/netplay/nettypes.cpp
@@ -125,18 +125,6 @@ static void queue(const Q &q, uint32_t &vOrig)
 	}
 }
 
-template<class Q>
-static void queueLarge(const Q &q, uint32_t &v)
-{
-	uint16_t b[2] = {uint16_t(v>>16), uint16_t(v)};
-	queue(q, b[0]);
-	queue(q, b[1]);
-	if (Q::Direction == Q::Read)
-	{
-		v = b[0]<<16 | b[1];
-	}
-}
-
 template<class Q>
 static void queue(const Q &q, uint64_t &v)
 {
@@ -287,19 +275,6 @@ static void queueAuto(T &v)
 	}
 }
 
-template<class T>
-static void queueAutoLarge(T &v)
-{
-	if (NETgetPacketDir() == PACKET_ENCODE)
-	{
-		queueLarge(writer, v);
-	}
-	else if (NETgetPacketDir() == PACKET_DECODE)
-	{
-		queueLarge(reader, v);
-	}
-}
-
 // Queue selection functions
 
 /// Gets the &NetQueuePair::send or NetQueue *, corresponding to queue.
@@ -577,11 +552,6 @@ void NETuint32_t(uint32_t *ip)
 	queueAuto(*ip);
 }
 
-void NETuint32_tLarge(uint32_t *ip)
-{
-	queueAutoLarge(*ip);
-}
-
 void NETint64_t(int64_t *ip)
 {
 	queueAuto(*ip);

diff --git a/lib/netplay/nettypes.h b/lib/netplay/nettypes.h
@@ -77,7 +77,6 @@ void NETint16_t(int16_t *ip);
 void NETuint16_t(uint16_t *ip);
 void NETint32_t(int32_t *ip);         ///< Encodes small values (< 836 288) in at most 3 bytes, large values (≥ 22 888 448) in 5 bytes.
 void NETuint32_t(uint32_t *ip);       ///< Encodes small values (< 1 672 576) in at most 3 bytes, large values (≥ 45 776 896) in 5 bytes.
-void NETuint32_tLarge(uint32_t *ip);  ///< Encodes all values in exactly 4 bytes.
 void NETint64_t(int64_t *ip);
 void NETuint64_t(uint64_t *ip);
 void NETbool(bool *bp);