Some small optimization in makeSplitPacket func. If we know data.getSize() and maximum_data_size we can calulate number of chunks. For example: size = 1105, max = 495. The number = (int)(size/max)+1=3 (2*495 + 115) where 115 - tail of data block. And we can write chunks_count in the first cycle.

After this optimisation we have 1 cycle and calc some variables around cycle.

src/connection.cpp

@@ -81,44 +81,36 @@ core::list<SharedBuffer<u8> > makeSplitPacket(
 		u16 seqnum)
 {
 	// Chunk packets, containing the TYPE_SPLIT header
-	core::list<SharedBuffer<u8> > chunks;
+    core::list<SharedBuffer<u8> > chunks;
 	
-	u32 chunk_header_size = 7;
-	u32 maximum_data_size = chunksize_max - chunk_header_size;
-	u32 start = 0;
-	u32 end = 0;
-	u32 chunk_num = 0;
-	do{
-		end = start + maximum_data_size - 1;
-		if(end > data.getSize() - 1)
-			end = data.getSize() - 1;
-		
-		u32 payload_size = end - start + 1;
-		u32 packet_size = chunk_header_size + payload_size;
-
-		SharedBuffer<u8> chunk(packet_size);
-		
-		writeU8(&chunk[0], TYPE_SPLIT);
-		writeU16(&chunk[1], seqnum);
-		// [3] u16 chunk_count is written at next stage
-		writeU16(&chunk[5], chunk_num);
-		memcpy(&chunk[chunk_header_size], &data[start], payload_size);
-
-		chunks.push_back(chunk);
-		
-		start = end + 1;
-		chunk_num++;
-	}
-	while(end != data.getSize() - 1);
-
-	u16 chunk_count = chunks.getSize();
-
-	core::list<SharedBuffer<u8> >::Iterator i = chunks.begin();
-	for(; i != chunks.end(); i++)
-	{
-		// Write chunk_count
-		writeU16(&((*i)[3]), chunk_count);
-	}
+    u32 chunk_header_size = 7;
+    u32 maximum_data_size = chunksize_max - chunk_header_size;
+    u32 start = 0;
+   // u32 end = 0;
+   // u32 chunk_num = 0;
+    u32 data_size = data.getSize(); //calc once, not in the cycle
+    u32 chunks_count = (u32)(data_size / maximum_data_size) +1;
+    u32 payload_size = maximum_data_size;
+   
+    for(int i=0; i<chunks_count;i++){
+        
+        SharedBuffer<u8> chunk(maximum_data_size + chunk_header_size);
+        
+        writeU8(&chunk[0], TYPE_SPLIT);
+        writeU16(&chunk[1], seqnum);
+        writeU16(&chunk[3], chunks_count);
+        writeU16(&chunk[5], i); // chunk number
+        
+        start = i * maximum_data_size; // 0, 1*dsize, 2*dsize...
+        
+        // on the last iteration
+        if((i+1) == chunks_count) 
+            // calc the tail which size smaller than maximum_data_size
+            payload_size = data_size - start; 
+        
+        memcpy(&chunk[chunk_header_size], &data[start], payload_size);
+        chunks.push_back(chunk);
+       }
 
 	return chunks;
 }