purezen 0.0.2

Runtime for the Pure Data (Pd) audio programming language, implemented as an extensible audio library allowing full control over signal processing, message passing, and graph manipulation. Pure Data is a graph-based programming language environment creating interactive music and multimedia works.
Documentation
/*
 *  Copyright 2009,2010,2011 Reality Jockey, Ltd.
 *                 info@rjdj.me
 *                 http://rjdj.me/
 *
 *  This file is part of ZenGarden.
 *
 *  ZenGarden is free software: you can redistribute it and/or modify
 *  it under the terms of the GNU Lesser General Public License as published by
 *  the Free Software Foundation, either version 3 of the License, or
 *  (at your option) any later version.
 *
 *  ZenGarden is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *  GNU Lesser General Public License for more details.
 *
 *  You should have received a copy of the GNU Lesser General Public License
 *  along with ZenGarden.  If not, see <http://www.gnu.org/licenses/>.
 *
 */

#include "MessageMetro.h"
#include "PdGraph.h"

message::Object *MessageMetro::new_object(pd::Message *init_message, PdGraph *graph) {
  return new MessageMetro(init_message, graph);
}

MessageMetro::MessageMetro(pd::Message *init_message, PdGraph *graph) : message::Object(2, 1, graph) {
  // default to interval of one second
  intervalInMs = init_message->is_float(0) ? (double) init_message->get_float(0) : 1000.0;
  pendingMessage = NULL;
}

MessageMetro::~MessageMetro() {
  // nothign to do. pendingMessage object is owned by context.
}

string MessageMetro::toString() {
  char str[snprintf(NULL, 0, "%s %g", get_object_label(), intervalInMs)+1];
  snprintf(str, sizeof(str), "%s %g", get_object_label(), intervalInMs);
  return string(str);
}

void MessageMetro::process_message(int inlet_index, pd::Message *message) {
  switch (inlet_index) {
    case 0: {
      switch (message->get_type(0)) {
        case FLOAT: {
          // any non-zero float may start the metro
          (message->get_float(0) == 0.0f) ? stopMetro() : startMetro(message->get_timestamp());
          break;
        }
        case SYMBOL: {
          if (message->is_symbol_str(0, "stop")) {
            stopMetro();
          }
          break;
        }
        case BANG: {
          startMetro(message->get_timestamp());
          break;
        }
        default: {
          break;
        }
      }
      break;
    }
    case 1: {
      if (message->is_float(0)) {
        intervalInMs = (double) message->get_float(0);
      }
      break;
    }
    default: {
      break;
    }
  }
}

void MessageMetro::send_message(int outlet_index, pd::Message *message) {
  // schedule the pending message before the current one is sent so that if a stop message
  // arrives at this object while in this function, then the next message can be cancelled
  pendingMessage = PD_MESSAGE_ON_STACK(1);
  pendingMessage->from_timestamp_and_bang(message->get_timestamp() + intervalInMs);
  pendingMessage = graph->schedule_message(this, 0, pendingMessage);

  message::Object::send_message(outlet_index, message);
}

void MessageMetro::startMetro(double timestamp) {
  // Ensure that there is no pending message for this metro. If there is, then cancel it.
  // This allows a metro to be banged multiple times and always restart the timing from the most
  // recently received bang.
  stopMetro();

  pd::Message *outgoing_message = PD_MESSAGE_ON_STACK(1);
  outgoing_message->from_timestamp_and_bang(timestamp);
  send_message(0, outgoing_message);
}

void MessageMetro::stopMetro() {
  if (pendingMessage != NULL) {
    graph->cancel_message(this, 0, pendingMessage);
    pendingMessage = NULL;
  }
}