Minecraft inventory packet parsing

gistfile1.txt

//Update player inventory
size_t mcmm_client::getInventory(netpacket *pkt )
{
    int32_t inv_type;
    int16_t inv_count;

    //Total length = 7 bytes + (4 shorts + health  OR  36 shorts + health)
    size_t packetsize = pkt->get_maxsize();
    size_t minimumsize = SIZE_INVENTORY;
    
    if (packetsize < minimumsize) {
        //Not enough to parse
        return 0;
    }

    //Read the inventory type and number of slots
    pkt->read(inv_type);
    pkt->read(inv_count);

    //Check packet size before reading more
    minimumsize += (inv_count * 2);
    if (packetsize < minimumsize) { return 0; }

    //Store item info in arrays
    int16_t item_id[inv_count];
    uint8_t item_count[inv_count];
    uint16_t item_health[inv_count];
    
    //Read the inventory items, and optionally health
    int16_t index;
    for (index = 0; index < inv_count; index++)
    {
        pkt->read(item_id[index]);
        if (item_id[index] != -1) {
            //Check new minimum size
            minimumsize += 3;
            if (packetsize < minimumsize) { return 0; }

            //Read item count and health
            pkt->read(item_count[index]);
            pkt->read(item_health[index]);
        }
    }

    netC.debugLog << "getInventory Type=" << inv_type << " Count=" << inv_count << endl;

    //Return number of bytes consumed
    return pkt->get_read();
}