OrdinaryMagician/vkdoom_m
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- Added selective compression of network packets. Interestingly, most packets

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don't actually compress all that well, even the ones that aren't too short
  to possibly compress. (Maybe make the whole thing one long, never-ending
  zlib data stream with Z_SYNC_FLUSH used to chunk things at packet
  boundaries? That would probably help the compression ratio, but it would
  require changing the way the netcode determines sequence, which would be
  a much more invasive change.)


SVN r1438 (trunk)
This commit is contained in:
Randy Heit 2009-02-22 05:05:58 +00:00
commit 10c31b82cb
4 changed files with 108 additions and 38 deletions
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74
src/i_net.cpp
View file

@ -64,7 +64,9 @@
#include "i_net.h"
// As per http://support.microsoft.com/kb/q192599/ the standard
// size for network buffers is 8k.
#define TRANSMIT_SIZE 8000
/* [Petteri] Get more portable: */
#ifndef __WIN32__
@ -133,6 +135,8 @@ struct PreGamePacket
} machines[MAXNETNODES];
};
BYTE TransmitBuffer[TRANSMIT_SIZE];
//
// UDPsocket
//
@ -191,11 +195,47 @@ void PacketSend (void)
{
int c;
//printf ("sending %i\n",gametic);
c = sendto (mysocket , (const char*)doomcom.data, doomcom.datalength
,0,(sockaddr *)&sendaddress[doomcom.remotenode]
,sizeof(sendaddress[doomcom.remotenode]));
// FIXME: Catch this before we've overflown the buffer. With long chat
// text and lots of backup tics, it could conceivably happen. (Though
// apparently it hasn't yet, which is good.)
if (doomcom.datalength > MAX_MSGLEN)
{
I_FatalError("Netbuffer overflow!");
}
uLong size = TRANSMIT_SIZE - 1;
if (doomcom.datalength >= 10)
{
assert(!(doomcom.data[0] & NCMD_COMPRESSED));
TransmitBuffer[0] = doomcom.data[0] | NCMD_COMPRESSED;
c = compress2(TransmitBuffer + 1, &size, doomcom.data + 1, doomcom.datalength - 1, 9);
size += 1;
}
else
{
c = -1; // Just some random error code to avoid sending the compressed buffer.
}
if (c == Z_OK && size < (uLong)doomcom.datalength)
{
// Printf("send %lu/%d\n", size, doomcom.datalength);
c = sendto(mysocket, (char *)TransmitBuffer, size,
0, (sockaddr *)&sendaddress[doomcom.remotenode],
sizeof(sendaddress[doomcom.remotenode]));
}
else
{
if (doomcom.datalength > TRANSMIT_SIZE)
{
I_Error("Net compression failed (zlib error %d)", c);
}
else
{
// Printf("send %d\n", doomcom.datalength);
c = sendto(mysocket, (char *)doomcom.data, doomcom.datalength,
0, (sockaddr *)&sendaddress[doomcom.remotenode],
sizeof(sendaddress[doomcom.remotenode]));
}
}
// if (c == -1)
// I_Error ("SendPacket error: %s",strerror(errno));
}
@ -212,8 +252,8 @@ void PacketGet (void)
int node;
fromlen = sizeof(fromaddress);
c = recvfrom (mysocket, (char*)doomcom.data, MAX_MSGLEN, 0
, (sockaddr *)&fromaddress, &fromlen);
c = recvfrom (mysocket, (char*)TransmitBuffer, TRANSMIT_SIZE, 0,
(sockaddr *)&fromaddress, &fromlen);
node = FindNode (&fromaddress);
if (node >= 0 && c == SOCKET_ERROR)
@ -239,6 +279,26 @@ void PacketGet (void)
return;
}
}
else if (c > 0)
{
doomcom.data[0] = TransmitBuffer[0] & ~NCMD_COMPRESSED;
if (TransmitBuffer[0] & NCMD_COMPRESSED)
{
uLongf msgsize = MAX_MSGLEN - 1;
int err = uncompress(doomcom.data + 1, &msgsize, TransmitBuffer + 1, c - 1);
// Printf("recv %d/%lu\n", c, msgsize + 1);
if (err != Z_OK)
{
I_Error("Net decompression failed (zlib error %d)\n", err);
}
c = msgsize + 1;
}
else
{
// Printf("recv %d\n", c);
memcpy(doomcom.data + 1, TransmitBuffer + 1, c - 1);
}
}
doomcom.remotenode = node;
doomcom.datalength = (short)c;