Changeset 1336 for code/branches/merge/src/network/PacketGenerator.cc

Timestamp:

May 20, 2008, 5:58:37 PM (16 years ago)

Author:

scheusso

Message:

added crc checksum testing for submitted gamestates (can also be used for other packet types)

File:

• code/branches/merge/src/network/PacketGenerator.cc (modified) (3 diffs)

code/branches/merge/src/network/PacketGenerator.cc

@@ -46 +46 @@
 namespace network
 {
+  void calcCRCBit(uint32_t &crc32, int bit){
+    int hbit;
+ 
+    hbit=(crc32 & 0x80000000) ? 1 : 0;
+    if (hbit != bit)
+      crc32=(crc32<<1) ^ NETWORK_CRC32POLY;
+    else
+      crc32=crc32<<1;
+  }
+  
+  uint32_t calcCRC(unsigned char *data, unsigned int dataLength){
+    uint32_t crc32=0;
+    for(unsigned int i=0; i<dataLength; i++){
+      calcCRCBit(crc32, (data[i]&0x1)>>0); // 1st bit
+      calcCRCBit(crc32, (data[i]&0x2)>>1); // 2nd bit
+      calcCRCBit(crc32, (data[i]&0x3)>>2); // 3rd bit
+      calcCRCBit(crc32, (data[i]&0x4)>>3); // 4th bit
+      calcCRCBit(crc32, (data[i]&0x5)>>4); // 5th bit
+      calcCRCBit(crc32, (data[i]&0x6)>>5); // 6th bit
+      calcCRCBit(crc32, (data[i]&0x7)>>6); // 7th bit
+      calcCRCBit(crc32, (data[i]&0x8)>>7); // 8th bit
+    }
+    return crc32;
+  }
+  
   PacketGenerator::PacketGenerator() { }
 
@@ -135 +160 @@
     memcpy( (void*)(data+5*sizeof( int ) + sizeof(bool)), (const void*)&(states->complete), sizeof(bool) );
     memcpy( (void*)(data+5*sizeof( int ) + 2*sizeof(bool)), (const void*)states->data, states->compsize );
+    
     //create an enet packet with the generated bytestream
     COUT(4) << "PacketGenerator generating totalLen " << totalLen << std::endl;
     ENetPacket *packet = enet_packet_create( data , totalLen, reliable );
     delete[] data;
+    if(!addCRC(packet))
+      COUT(3) << "could not add crc to gamestate packet" << std::endl;
     return packet;
   }
@@ -174 +202 @@
     return packet;
   }
+  
+  
+  bool PacketGenerator::addCRC( ENetPacket *packet){
+    unsigned char *data = packet->data;
+    uint32_t crc32=calcCRC(data, packet->dataLength);
+    // now append the crc to the packet data
+    int oldlength = packet->dataLength;
+    if(enet_packet_resize(packet, packet->dataLength+sizeof(uint32_t))==0){
+      memcpy(&packet->data[oldlength], &crc32, sizeof(uint32_t));
+      return true;
+    }else{
+      COUT(3) << "could not add crc to gamestate" << std::endl;
+      return false;
+    }
+  }
 
 }