gr_message_source.h

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/* -*- c++ -*- */
/*
 * Copyright 2005 Free Software Foundation, Inc.
 *
 * This file is part of GNU Radio
 *
 * GNU Radio is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 3, or (at your option)
 * any later version.
 *
 * GNU Radio 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 General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with GNU Radio; see the file COPYING.  If not, write to
 * the Free Software Foundation, Inc., 51 Franklin Street,
 * Boston, MA 02110-1301, USA.
 */

#ifndef INCLUDED_GR_MESSAGE_SOURCE_H
#define INCLUDED_GR_MESSAGE_SOURCE_H

#include <gr_core_api.h>
#include <gr_sync_block.h>
#include <gr_message.h>
#include <gr_msg_queue.h>

class gr_message_source;
typedef boost::shared_ptr<gr_message_source> gr_message_source_sptr;

GR_CORE_API gr_message_source_sptr gr_make_message_source (size_t itemsize, int msgq_limit=0);
GR_CORE_API gr_message_source_sptr gr_make_message_source (size_t itemsize, gr_msg_queue_sptr msgq);
GR_CORE_API gr_message_source_sptr gr_make_message_source (size_t itemsize, gr_msg_queue_sptr msgq,
                                                           const std::string& lengthtagname);

/*!
 * \brief Turn received messages into a stream
 * \ingroup source_blk
 */
class GR_CORE_API gr_message_source : public gr_sync_block
{
 private:
  size_t                d_itemsize;
  gr_msg_queue_sptr     d_msgq;
  gr_message_sptr       d_msg;
  unsigned              d_msg_offset;
  bool                  d_eof;
  bool d_tags;
  // FIXME: Is this adequate tagname length.
  std::string d_lengthtagname;

  friend GR_CORE_API gr_message_source_sptr
    gr_make_message_source(size_t itemsize, int msgq_limit);
  friend GR_CORE_API gr_message_source_sptr
    gr_make_message_source(size_t itemsize, gr_msg_queue_sptr msgq);
  friend GR_CORE_API gr_message_source_sptr
    gr_make_message_source(size_t itemsize, gr_msg_queue_sptr msgq, const std::string& lengthtagname);

 protected:
  gr_message_source (size_t itemsize, int msgq_limit);
  gr_message_source (size_t itemsize, gr_msg_queue_sptr msgq);
  gr_message_source (size_t itemsize, gr_msg_queue_sptr msgq, const std::string& lengthtagname);

 public:
  ~gr_message_source ();

  gr_msg_queue_sptr     msgq() const { return d_msgq; }

  int work (int noutput_items,
            gr_vector_const_void_star &input_items,
            gr_vector_void_star &output_items);
};

#endif /* INCLUDED_GR_MESSAGE_SOURCE_H */