Question

I would like to create something like this :

I have a module that does something like ‘circuit switching’ for a stream of messages. That is, it has a single inport and multiple outports. Once a message arrives at the inport, an outport is selected based on some logic (logic is not important in the context of the question). It is checked whether, there is any ongoing message transfer on the outport (for the first message, there won’t be any). If there is no transfer, message is sent to that outport, otherwise, it is kept in queue for that particular outport. I need to decide data structure for this communication. Please advice

My idea is to have a map of outports and corresponding queues.

queue<message> m_incoming_queue;
typedef map<outport*,m_incoming_queue> transaction_map

if this is a good solution, i want to know how do I create a queue at the runtime? as in, I dont know in advance how many outports will there be, I create outports based on requirement.

Answer 1

Maybe something like:

// At beginning
typedef queue<message> MessageQueue
typedef map<outport*, MessageQueue> transaction_map
transaction_map tm()  // Create the transaction map


// On receipt of each message
// (Some logic that determines outport* op and message m)
if(tm.count(*op) == 0)
{
    // There are no queues yet, create one and insert it
    tm.insert(transaction_map::value_type(*op, MessageQueue()))
}
// There is already a queue created, so add to it
tm[*op].push(m)