norm_engine.cpp

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#include "precompiled.hpp"
 
#include "platform.hpp"
 
#if defined ZMQ_HAVE_NORM
 
#include "norm_engine.hpp"
#ifdef ZMQ_USE_NORM_SOCKET_WRAPPER
#include "ip.hpp"
#endif
 
#include "session_base.hpp"
#include "v2_protocol.hpp"
 
 
#ifdef ZMQ_USE_NORM_SOCKET_WRAPPER
 
struct norm_wrapper_thread_args_t
{
    NormDescriptor norm_descriptor;
    SOCKET wrapper_write_fd;
    NormInstanceHandle norm_instance_handle;
};
 
DWORD WINAPI normWrapperThread (LPVOID lpParam);
#endif
 
zmq::norm_engine_t::norm_engine_t (io_thread_t *parent_,
                                   const options_t &options_) :
    io_object_t (parent_),
    zmq_session (NULL),
    options (options_),
    norm_instance (NORM_INSTANCE_INVALID),
    norm_session (NORM_SESSION_INVALID),
    is_sender (false),
    is_receiver (false),
    zmq_encoder (0),
    norm_tx_stream (NORM_OBJECT_INVALID),
    tx_first_msg (true),
    tx_more_bit (false),
    zmq_output_ready (false),
    norm_tx_ready (false),
    tx_index (0),
    tx_len (0),
    zmq_input_ready (false)
{
    int rc = tx_msg.init ();
    errno_assert (0 == rc);
}
 
zmq::norm_engine_t::~norm_engine_t ()
{
    shutdown (); // in case it was not already called
}
 
 
int zmq::norm_engine_t::init (const char *network_, bool send, bool recv)
{
    // Parse the "network_" address int "iface", "addr", and "port"
    // norm endpoint format: [id,][<iface>;]<addr>:<port>
    // First, look for optional local NormNodeId
    // (default NORM_NODE_ANY causes NORM to use host IP addr for NormNodeId)
    NormNodeId localId = NORM_NODE_ANY;
    const char *ifacePtr = strchr (network_, ',');
    if (NULL != ifacePtr) {
        size_t idLen = ifacePtr - network_;
        if (idLen > 31)
            idLen = 31;
        char idText[32];
        strncpy (idText, network_, idLen);
        idText[idLen] = '\0';
        localId = (NormNodeId) atoi (idText);
        ifacePtr++;
    } else {
        ifacePtr = network_;
    }
 
    // Second, look for optional multicast ifaceName
    char ifaceName[256];
    const char *addrPtr = strchr (ifacePtr, ';');
    if (NULL != addrPtr) {
        size_t ifaceLen = addrPtr - ifacePtr;
        if (ifaceLen > 255)
            ifaceLen = 255; // return error instead?
        strncpy (ifaceName, ifacePtr, ifaceLen);
        ifaceName[ifaceLen] = '\0';
        ifacePtr = ifaceName;
        addrPtr++;
    } else {
        addrPtr = ifacePtr;
        ifacePtr = NULL;
    }
 
    // Finally, parse IP address and port number
    const char *portPtr = strrchr (addrPtr, ':');
    if (NULL == portPtr) {
        errno = EINVAL;
        return -1;
    }
 
    char addr[256];
    size_t addrLen = portPtr - addrPtr;
    if (addrLen > 255)
        addrLen = 255;
    strncpy (addr, addrPtr, addrLen);
    addr[addrLen] = '\0';
    portPtr++;
    unsigned short portNumber = atoi (portPtr);
 
    if (NORM_INSTANCE_INVALID == norm_instance) {
        if (NORM_INSTANCE_INVALID == (norm_instance = NormCreateInstance ())) {
            // errno set by whatever caused NormCreateInstance() to fail
            return -1;
        }
    }
 
    // TBD - What do we use for our local NormNodeId?
    //       (for now we use automatic, IP addr based assignment or passed in 'id')
    //       a) Use ZMQ Identity somehow?
    //       b) Add function to use iface addr
    //       c) Randomize and implement a NORM session layer
    //          conflict detection/resolution protocol
 
    norm_session = NormCreateSession (norm_instance, addr, portNumber, localId);
    if (NORM_SESSION_INVALID == norm_session) {
        int savedErrno = errno;
        NormDestroyInstance (norm_instance);
        norm_instance = NORM_INSTANCE_INVALID;
        errno = savedErrno;
        return -1;
    }
    // There's many other useful NORM options that could be applied here
    if (!NormIsUnicastAddress (addr)) {
        // These only apply for multicast sessions
        NormSetTTL (norm_session, options.multicast_hops);
        NormSetRxPortReuse (
          norm_session,
          true); // port reuse doesn't work for non-connected unicast
        NormSetLoopback (norm_session,
                         true); // needed when multicast users on same machine
        if (NULL != ifacePtr) {
            // Note a bad interface may not be caught until sender or receiver start
            // (Since sender/receiver is not yet started, this always succeeds here)
            NormSetMulticastInterface (norm_session, ifacePtr);
        }
    }
    if (NormIsUnicastAddress (addr) || options.norm_unicast_nacks) {
        NormSetDefaultUnicastNack (norm_session, true);
    }
    // Set TOS but check TOS ECN bit for CCE modes
    if ((options.norm_mode == ZMQ_NORM_CCE
         || options.norm_mode == ZMQ_NORM_CCE_ECNONLY)
        && (options.tos % 4 == 0)) {
        // ECN Capable Transport not set, so set it
        NormSetTOS (norm_session, options.tos + 1);
    } else if ((options.norm_mode == ZMQ_NORM_CCE
                || options.norm_mode == ZMQ_NORM_CCE_ECNONLY)
               && (options.tos % 4 == 3)) {
        // Congestion Experienced is an invalid setting, remove one of the bits
        NormSetTOS (norm_session, options.tos - 1);
    } else {
        NormSetTOS (norm_session, options.tos);
    }
 
    if (recv) {
        // The alternative NORM_SYNC_CURRENT here would provide "instant"
        // receiver sync to the sender's _current_ message transmission.
        // NORM_SYNC_STREAM tries to get everything the sender has cached/buffered
        NormSetDefaultSyncPolicy (norm_session, NORM_SYNC_STREAM);
        if (!NormStartReceiver (
              norm_session, (unsigned long) options.norm_buffer_size * 1024)) {
            // errno set by whatever failed
            int savedErrno = errno;
            NormDestroyInstance (norm_instance); // session gets closed, too
            norm_session = NORM_SESSION_INVALID;
            norm_instance = NORM_INSTANCE_INVALID;
            errno = savedErrno;
            return -1;
        }
        is_receiver = true;
    }
 
    if (send) {
        // Handle invalid settings -- num_parity must be >= num_autoparity (which has a default of 0)
        unsigned char numparity =
          (options.norm_num_parity >= options.norm_num_autoparity
             ? options.norm_num_parity
             : options.norm_num_autoparity);
        // Handle invalid settings -- block size must be > effective num_parity (which is <255)
        unsigned char blocksize =
          (options.norm_block_size > numparity ? options.norm_block_size
                                               : numparity + 1);
        // Pick a random sender instance id (aka norm sender session id)
        NormSessionId instanceId = NormGetRandomSessionId ();
        // TBD - provide "options" for some NORM sender parameters
        if (!NormStartSender (norm_session, instanceId,
                              (unsigned long) options.norm_buffer_size * 1024,
                              options.norm_segment_size, blocksize,
                              numparity)) {
            // errno set by whatever failed
            int savedErrno = errno;
            NormDestroyInstance (norm_instance); // session gets closed, too
            norm_session = NORM_SESSION_INVALID;
            norm_instance = NORM_INSTANCE_INVALID;
            errno = savedErrno;
            return -1;
        }
        // Handle NORM mode
        if (options.norm_mode == ZMQ_NORM_FIXED) {
            NormSetTxRate (norm_session, (double) options.rate * 1000);
        } else {
            NormSetCongestionControl (norm_session, true);
            if (options.norm_mode != ZMQ_NORM_CC) {
                NormSetEcnSupport (
                  norm_session,
                  ((options.norm_mode == ZMQ_NORM_CCE)
                   || (options.norm_mode == ZMQ_NORM_CCE_ECNONLY)),
                  options.norm_mode == ZMQ_NORM_CCE_ECNONLY,
                  options.norm_mode == ZMQ_NORM_CCL);
            }
        }
        if (options.norm_num_autoparity > 0) {
            NormSetAutoParity (norm_session, options.norm_num_autoparity);
        }
        norm_tx_ready = true;
        is_sender = true;
        if (NORM_OBJECT_INVALID
            == (norm_tx_stream = NormStreamOpen (
                  norm_session,
                  (unsigned long) options.norm_buffer_size * 1024))) {
            // errno set by whatever failed
            int savedErrno = errno;
            NormDestroyInstance (norm_instance); // session gets closed, too
            norm_session = NORM_SESSION_INVALID;
            norm_instance = NORM_INSTANCE_INVALID;
            errno = savedErrno;
            return -1;
        }
        // NORM Stream options
        NormStreamSetPushEnable (norm_tx_stream, options.norm_push_enable);
    }
 
    //NormSetMessageTrace(norm_session, true);
    //NormSetDebugLevel(3);
    //NormOpenDebugLog(norm_instance, "normLog.txt");
 
    return 0; // no error
} // end zmq::norm_engine_t::init()
 
void zmq::norm_engine_t::shutdown ()
{
    // TBD - implement a more graceful shutdown option
    if (is_receiver) {
        NormStopReceiver (norm_session);
 
        // delete any active NormRxStreamState
        rx_pending_list.Destroy ();
        rx_ready_list.Destroy ();
        msg_ready_list.Destroy ();
 
        is_receiver = false;
    }
    if (is_sender) {
        NormStopSender (norm_session);
        is_sender = false;
    }
    if (NORM_SESSION_INVALID != norm_session) {
        NormDestroySession (norm_session);
        norm_session = NORM_SESSION_INVALID;
    }
    if (NORM_INSTANCE_INVALID != norm_instance) {
        NormStopInstance (norm_instance);
        NormDestroyInstance (norm_instance);
        norm_instance = NORM_INSTANCE_INVALID;
    }
} // end zmq::norm_engine_t::shutdown()
 
void zmq::norm_engine_t::plug (io_thread_t *io_thread_,
                               session_base_t *session_)
{
#ifdef ZMQ_USE_NORM_SOCKET_WRAPPER
    norm_wrapper_thread_args_t *threadArgs = new norm_wrapper_thread_args_t;
    int rc = make_fdpair (&wrapper_read_fd, &threadArgs->wrapper_write_fd);
    errno_assert (rc != -1);
 
    threadArgs->norm_descriptor = NormGetDescriptor (norm_instance);
    threadArgs->norm_instance_handle = norm_instance;
    norm_descriptor_handle = add_fd (wrapper_read_fd);
#else
    fd_t normDescriptor = NormGetDescriptor (norm_instance);
    norm_descriptor_handle = add_fd (normDescriptor);
#endif
    // Set POLLIN for notification of pending NormEvents
    set_pollin (norm_descriptor_handle);
    // TBD - we may assign the NORM engine to an io_thread in the future???
    zmq_session = session_;
    if (is_sender)
        zmq_output_ready = true;
    if (is_receiver)
        zmq_input_ready = true;
 
 
    if (is_sender)
        send_data ();
 
#ifdef ZMQ_USE_NORM_SOCKET_WRAPPER
    wrapper_thread_handle = CreateThread (NULL, 0, normWrapperThread,
                                          threadArgs, 0, &wrapper_thread_id);
#endif
 
} // end zmq::norm_engine_t::init()
 
void zmq::norm_engine_t::unplug ()
{
    rm_fd (norm_descriptor_handle);
#ifdef ZMQ_USE_NORM_SOCKET_WRAPPER
    PostThreadMessage (wrapper_thread_id, WM_QUIT, (WPARAM) NULL,
                       (LPARAM) NULL);
    WaitForSingleObject (wrapper_thread_handle, INFINITE);
    DWORD exitCode;
    GetExitCodeThread (wrapper_thread_handle, &exitCode);
    zmq_assert (exitCode != -1);
    int rc = closesocket (wrapper_read_fd);
    errno_assert (rc != -1);
#endif
    zmq_session = NULL;
} // end zmq::norm_engine_t::unplug()
 
void zmq::norm_engine_t::terminate ()
{
    unplug ();
    shutdown ();
    delete this;
}
 
void zmq::norm_engine_t::restart_output ()
{
    // There's new message data available from the session
    zmq_output_ready = true;
    if (norm_tx_ready)
        send_data ();
 
} // end zmq::norm_engine_t::restart_output()
 
void zmq::norm_engine_t::send_data ()
{
    // Here we write as much as is available or we can
    while (zmq_output_ready && norm_tx_ready) {
        if (0 == tx_len) {
            // Our tx_buffer needs data to send
            // Get more data from encoder
            size_t space = BUFFER_SIZE;
            unsigned char *bufPtr = (unsigned char *) tx_buffer;
            tx_len = zmq_encoder.encode (&bufPtr, space);
            if (0 == tx_len) {
                if (tx_first_msg) {
                    // We don't need to mark eom/flush until a message is sent
                    tx_first_msg = false;
                } else {
                    // A prior message was completely written to stream, so
                    // mark end-of-message and possibly flush (to force packet transmission,
                    // even if it's not a full segment so message gets delivered quickly)
                    // NormStreamMarkEom(norm_tx_stream);  // the flush below marks eom
                    // Note NORM_FLUSH_ACTIVE makes NORM fairly chatty for low duty cycle messaging
                    // but makes sure content is delivered quickly.  Positive acknowledgements
                    // with flush override would make NORM more succinct here
                    NormStreamFlush (norm_tx_stream, true, NORM_FLUSH_ACTIVE);
                }
                // Need to pull and load a new message to send
                if (-1 == zmq_session->pull_msg (&tx_msg)) {
                    // We need to wait for "restart_output()" to be called by ZMQ
                    zmq_output_ready = false;
                    break;
                }
                zmq_encoder.load_msg (&tx_msg);
                // Should we write message size header for NORM to use? Or expect NORM
                // receiver to decode ZMQ message framing format(s)?
                // OK - we need to use a byte to denote when the ZMQ frame is the _first_
                //      frame of a message so it can be decoded properly when a receiver
                //      'syncs' mid-stream.  We key off the the state of the 'more_flag'
                //      I.e.,If  more_flag _was_ false previously, this is the first
                //      frame of a ZMQ message.
                if (tx_more_bit)
                    tx_buffer[0] =
                      (char) 0xff; // this is not first frame of message
                else
                    tx_buffer[0] = 0x00; // this is first frame of message
                tx_more_bit = (0 != (tx_msg.flags () & msg_t::more));
                // Go ahead an get a first chunk of the message
                bufPtr++;
                space--;
                tx_len = 1 + zmq_encoder.encode (&bufPtr, space);
                tx_index = 0;
            }
        }
        // Do we have data in our tx_buffer pending
        if (tx_index < tx_len) {
            // We have data in our tx_buffer to send, so write it to the stream
            tx_index += NormStreamWrite (norm_tx_stream, tx_buffer + tx_index,
                                         tx_len - tx_index);
            if (tx_index < tx_len) {
                // NORM stream buffer full, wait for NORM_TX_QUEUE_VACANCY
                norm_tx_ready = false;
                break;
            }
            tx_len = 0; // all buffered data was written
        }
    } // end while (zmq_output_ready && norm_tx_ready)
} // end zmq::norm_engine_t::send_data()
 
void zmq::norm_engine_t::in_event ()
{
    // This means a NormEvent is pending, so call NormGetNextEvent() and handle
    NormEvent event;
#ifdef ZMQ_USE_NORM_SOCKET_WRAPPER
    int rc = recv (wrapper_read_fd, reinterpret_cast<char *> (&event),
                   sizeof (event), 0);
    errno_assert (rc == sizeof (event));
#else
    if (!NormGetNextEvent (norm_instance, &event)) {
        // NORM has died before we unplugged?!
        zmq_assert (false);
        return;
    }
#endif
 
    switch (event.type) {
        case NORM_TX_QUEUE_VACANCY:
        case NORM_TX_QUEUE_EMPTY:
            if (!norm_tx_ready) {
                norm_tx_ready = true;
                send_data ();
            }
            break;
 
        case NORM_RX_OBJECT_NEW:
            //break;
        case NORM_RX_OBJECT_UPDATED:
            recv_data (event.object);
            break;
 
        case NORM_RX_OBJECT_ABORTED: {
            NormRxStreamState *rxState =
              (NormRxStreamState *) NormObjectGetUserData (event.object);
            if (NULL != rxState) {
                // Remove the state from the list it's in
                // This is now unnecessary since deletion takes care of list removal
                // but in the interest of being clear ...
                NormRxStreamState::List *list = rxState->AccessList ();
                if (NULL != list)
                    list->Remove (*rxState);
            }
            delete rxState;
            break;
        }
        case NORM_REMOTE_SENDER_INACTIVE:
            // Here we free resources used for this formerly active sender.
            // Note w/ NORM_SYNC_STREAM, if sender reactivates, we may
            //  get some messages delivered twice.  NORM_SYNC_CURRENT would
            // mitigate that but might miss data at startup. Always tradeoffs.
            // Instead of immediately deleting, we could instead initiate a
            // user configurable timeout here to wait some amount of time
            // after this event to declare the remote sender truly dead
            // and delete its state???
            NormNodeDelete (event.sender);
            break;
 
        default:
            // We ignore some NORM events
            break;
    }
} // zmq::norm_engine_t::in_event()
 
bool zmq::norm_engine_t::restart_input ()
{
    // TBD - should we check/assert that zmq_input_ready was false???
    zmq_input_ready = true;
    // Process any pending received messages
    if (!msg_ready_list.IsEmpty ())
        recv_data (NORM_OBJECT_INVALID);
 
    return true;
} // end zmq::norm_engine_t::restart_input()
 
void zmq::norm_engine_t::recv_data (NormObjectHandle object)
{
    if (NORM_OBJECT_INVALID != object) {
        // Call result of NORM_RX_OBJECT_UPDATED notification
        // This is a rx_ready indication for a new or existing rx stream
        // First, determine if this is a stream we already know
        zmq_assert (NORM_OBJECT_STREAM == NormObjectGetType (object));
        // Since there can be multiple senders (publishers), we keep
        // state for each separate rx stream.
        NormRxStreamState *rxState =
          (NormRxStreamState *) NormObjectGetUserData (object);
        if (NULL == rxState) {
            // This is a new stream, so create rxState with zmq decoder, etc
            rxState = new (std::nothrow)
              NormRxStreamState (object, options.maxmsgsize, options.zero_copy,
                                 options.in_batch_size);
            errno_assert (rxState);
 
            if (!rxState->Init ()) {
                errno_assert (false);
                delete rxState;
                return;
            }
            NormObjectSetUserData (object, rxState);
        } else if (!rxState->IsRxReady ()) {
            // Existing non-ready stream, so remove from pending
            // list to be promoted to rx_ready_list ...
            rx_pending_list.Remove (*rxState);
        }
        if (!rxState->IsRxReady ()) {
            // TBD - prepend up front for immediate service?
            rxState->SetRxReady (true);
            rx_ready_list.Append (*rxState);
        }
    }
    // This loop repeats until we've read all data available from "rx ready" inbound streams
    // and pushed any accumulated messages we can up to the zmq session.
    while (!rx_ready_list.IsEmpty ()
           || (zmq_input_ready && !msg_ready_list.IsEmpty ())) {
        // Iterate through our rx_ready streams, reading data into the decoder
        // (This services incoming "rx ready" streams in a round-robin fashion)
        NormRxStreamState::List::Iterator iterator (rx_ready_list);
        NormRxStreamState *rxState;
        while (NULL != (rxState = iterator.GetNextItem ())) {
            switch (rxState->Decode ()) {
                case 1: // msg completed
                    // Complete message decoded, move this stream to msg_ready_list
                    // to push the message up to the session below.  Note the stream
                    // will be returned to the "rx_ready_list" after that's done
                    rx_ready_list.Remove (*rxState);
                    msg_ready_list.Append (*rxState);
                    continue;
 
                case -1: // decoding error (shouldn't happen w/ NORM, but ...)
                    // We need to re-sync this stream (decoder buffer was reset)
                    rxState->SetSync (false);
                    break;
 
                default: // 0 - need more data
                    break;
            }
            // Get more data from this stream
            NormObjectHandle stream = rxState->GetStreamHandle ();
            // First, make sure we're in sync ...
            while (!rxState->InSync ()) {
                // seek NORM message start
                if (!NormStreamSeekMsgStart (stream)) {
                    // Need to wait for more data
                    break;
                }
                // read message 'flag' byte to see if this it's a 'final' frame
                char syncFlag;
                unsigned int numBytes = 1;
                if (!NormStreamRead (stream, &syncFlag, &numBytes)) {
                    // broken stream (can happen on late-joining subscriber)
                    continue;
                }
                if (0 == numBytes) {
                    // This probably shouldn't happen either since we found msg start
                    // Need to wait for more data
                    break;
                }
                if (0 == syncFlag)
                    rxState->SetSync (true);
                // else keep seeking ...
            } // end while(!rxState->InSync())
            if (!rxState->InSync ()) {
                // Need more data for this stream, so remove from "rx ready"
                // list and iterate to next "rx ready" stream
                rxState->SetRxReady (false);
                // Move from rx_ready_list to rx_pending_list
                rx_ready_list.Remove (*rxState);
                rx_pending_list.Append (*rxState);
                continue;
            }
            // Now we're actually ready to read data from the NORM stream to the zmq_decoder
            // the underlying zmq_decoder->get_buffer() call sets how much is needed.
            unsigned int numBytes = rxState->GetBytesNeeded ();
            if (!NormStreamRead (stream, rxState->AccessBuffer (), &numBytes)) {
                // broken NORM stream, so re-sync
                rxState->Init (); // TBD - check result
                // This will retry syncing, and getting data from this stream
                // since we don't increment the "it" iterator
                continue;
            }
            rxState->IncrementBufferCount (numBytes);
            if (0 == numBytes) {
                // All the data available has been read
                // Need to wait for NORM_RX_OBJECT_UPDATED for this stream
                rxState->SetRxReady (false);
                // Move from rx_ready_list to rx_pending_list
                rx_ready_list.Remove (*rxState);
                rx_pending_list.Append (*rxState);
            }
        } // end while(NULL != (rxState = iterator.GetNextItem()))
 
        if (zmq_input_ready) {
            // At this point, we've made a pass through the "rx_ready" stream list
            // Now make a pass through the "msg_pending" list (if the zmq session
            // ready for more input).  This may possibly return streams back to
            // the "rx ready" stream list after their pending message is handled
            NormRxStreamState::List::Iterator iterator (msg_ready_list);
            NormRxStreamState *rxState;
            while (NULL != (rxState = iterator.GetNextItem ())) {
                msg_t *msg = rxState->AccessMsg ();
                int rc = zmq_session->push_msg (msg);
                if (-1 == rc) {
                    if (EAGAIN == errno) {
                        // need to wait until session calls "restart_input()"
                        zmq_input_ready = false;
                        break;
                    } else {
                        // session rejected message?
                        // TBD - handle this better
                        zmq_assert (false);
                    }
                }
                // else message was accepted.
                msg_ready_list.Remove (*rxState);
                if (
                  rxState
                    ->IsRxReady ()) // Move back to "rx_ready" list to read more data
                    rx_ready_list.Append (*rxState);
                else // Move back to "rx_pending" list until NORM_RX_OBJECT_UPDATED
                    msg_ready_list.Append (*rxState);
            } // end while(NULL != (rxState = iterator.GetNextItem()))
        }     // end if (zmq_input_ready)
    } // end while ((!rx_ready_list.empty() || (zmq_input_ready && !msg_ready_list.empty()))
 
    // Alert zmq of the messages we have pushed up
    zmq_session->flush ();
 
} // end zmq::norm_engine_t::recv_data()
 
zmq::norm_engine_t::NormRxStreamState::NormRxStreamState (
  NormObjectHandle normStream,
  int64_t maxMsgSize,
  bool zeroCopy,
  int inBatchSize) :
    norm_stream (normStream),
    max_msg_size (maxMsgSize),
    zero_copy (zeroCopy),
    in_batch_size (inBatchSize),
    in_sync (false),
    rx_ready (false),
    zmq_decoder (NULL),
    skip_norm_sync (false),
    buffer_ptr (NULL),
    buffer_size (0),
    buffer_count (0),
    prev (NULL),
    next (NULL),
    list (NULL)
{
}
 
zmq::norm_engine_t::NormRxStreamState::~NormRxStreamState ()
{
    if (NULL != zmq_decoder) {
        delete zmq_decoder;
        zmq_decoder = NULL;
    }
    if (NULL != list) {
        list->Remove (*this);
        list = NULL;
    }
}
 
bool zmq::norm_engine_t::NormRxStreamState::Init ()
{
    in_sync = false;
    skip_norm_sync = false;
    if (NULL != zmq_decoder)
        delete zmq_decoder;
    zmq_decoder =
      new (std::nothrow) v2_decoder_t (in_batch_size, max_msg_size, zero_copy);
    alloc_assert (zmq_decoder);
    if (NULL != zmq_decoder) {
        buffer_count = 0;
        buffer_size = 0;
        zmq_decoder->get_buffer (&buffer_ptr, &buffer_size);
        return true;
    } else {
        return false;
    }
} // end zmq::norm_engine_t::NormRxStreamState::Init()
 
// This decodes any pending data sitting in our stream decoder buffer
// It returns 1 upon message completion, -1 on error, 1 on msg completion
int zmq::norm_engine_t::NormRxStreamState::Decode ()
{
    // If we have pending bytes to decode, process those first
    while (buffer_count > 0) {
        // There's pending data for the decoder to decode
        size_t processed = 0;
 
        // This a bit of a kludgy approach used to weed
        // out the NORM ZMQ message transport "syncFlag" byte
        // from the ZMQ message stream being decoded (but it works!)
        if (skip_norm_sync) {
            buffer_ptr++;
            buffer_count--;
            skip_norm_sync = false;
        }
 
        int rc = zmq_decoder->decode (buffer_ptr, buffer_count, processed);
        buffer_ptr += processed;
        buffer_count -= processed;
        switch (rc) {
            case 1:
                // msg completed
                if (0 == buffer_count) {
                    buffer_size = 0;
                    zmq_decoder->get_buffer (&buffer_ptr, &buffer_size);
                }
                skip_norm_sync = true;
                return 1;
            case -1:
                // decoder error (reset decoder and state variables)
                in_sync = false;
                skip_norm_sync = false; // will get consumed by norm sync check
                Init ();
                break;
 
            case 0:
                // need more data, keep decoding until buffer exhausted
                break;
        }
    }
    // Reset buffer pointer/count for next read
    buffer_count = 0;
    buffer_size = 0;
    zmq_decoder->get_buffer (&buffer_ptr, &buffer_size);
    return 0; //  need more data
 
} // end zmq::norm_engine_t::NormRxStreamState::Decode()
 
zmq::norm_engine_t::NormRxStreamState::List::List () : head (NULL), tail (NULL)
{
}
 
zmq::norm_engine_t::NormRxStreamState::List::~List ()
{
    Destroy ();
}
 
void zmq::norm_engine_t::NormRxStreamState::List::Destroy ()
{
    NormRxStreamState *item = head;
    while (NULL != item) {
        Remove (*item);
        delete item;
        item = head;
    }
} // end zmq::norm_engine_t::NormRxStreamState::List::Destroy()
 
void zmq::norm_engine_t::NormRxStreamState::List::Append (
  NormRxStreamState &item)
{
    item.prev = tail;
    if (NULL != tail)
        tail->next = &item;
    else
        head = &item;
    item.next = NULL;
    tail = &item;
    item.list = this;
} // end zmq::norm_engine_t::NormRxStreamState::List::Append()
 
void zmq::norm_engine_t::NormRxStreamState::List::Remove (
  NormRxStreamState &item)
{
    if (NULL != item.prev)
        item.prev->next = item.next;
    else
        head = item.next;
    if (NULL != item.next)
        item.next->prev = item.prev;
    else
        tail = item.prev;
    item.prev = item.next = NULL;
    item.list = NULL;
} // end zmq::norm_engine_t::NormRxStreamState::List::Remove()
 
zmq::norm_engine_t::NormRxStreamState::List::Iterator::Iterator (
  const List &list) :
    next_item (list.head)
{
}
 
zmq::norm_engine_t::NormRxStreamState *
zmq::norm_engine_t::NormRxStreamState::List::Iterator::GetNextItem ()
{
    NormRxStreamState *nextItem = next_item;
    if (NULL != nextItem)
        next_item = nextItem->next;
    return nextItem;
} // end zmq::norm_engine_t::NormRxStreamState::List::Iterator::GetNextItem()
 
const zmq::endpoint_uri_pair_t &zmq::norm_engine_t::get_endpoint () const
{
    return _empty_endpoint;
}
 
 
#ifdef ZMQ_USE_NORM_SOCKET_WRAPPER
#include <iostream>
DWORD WINAPI normWrapperThread (LPVOID lpParam)
{
    norm_wrapper_thread_args_t *norm_wrapper_thread_args =
      (norm_wrapper_thread_args_t *) lpParam;
    NormEvent message;
    DWORD waitRc;
    DWORD exitCode = 0;
    int rc;
 
    for (;;) {
        // wait for norm event or message
        waitRc = MsgWaitForMultipleObjectsEx (
          1, &norm_wrapper_thread_args->norm_descriptor, INFINITE,
          QS_ALLPOSTMESSAGE, 0);
 
        // Check if norm event
        if (waitRc == WAIT_OBJECT_0) {
            // Process norm event
            if (!NormGetNextEvent (
                  norm_wrapper_thread_args->norm_instance_handle, &message)) {
                exitCode = -1;
                break;
            }
            rc =
              send (norm_wrapper_thread_args->wrapper_write_fd,
                    reinterpret_cast<char *> (&message), sizeof (message), 0);
            errno_assert (rc != -1);
            // Check if message
        } else if (waitRc == WAIT_OBJECT_0 + 1) {
            // Exit if WM_QUIT is received otherwise do nothing
            MSG message;
            GetMessage (&message, 0, 0, 0);
            if (message.message == WM_QUIT) {
                break;
            } else {
                // do nothing
            }
            // Otherwise an error occurred
        } else {
            exitCode = -1;
            break;
        }
    }
    // Free resources
    rc = closesocket (norm_wrapper_thread_args->wrapper_write_fd);
    free (norm_wrapper_thread_args);
    errno_assert (rc != -1);
 
    return exitCode;
}
 
#endif
 
#endif // ZMQ_HAVE_NORM