gr_sync_decimator.h

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/* -*- c++ -*- */
/*
 * Copyright 2004 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_SYNC_DECIMATOR_H
#define INCLUDED_GR_SYNC_DECIMATOR_H

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

/*!
 * \brief synchronous N:1 input to output with history
 * \ingroup base_blk
 *
 * Override work to provide the signal processing implementation.
 */
class GR_CORE_API gr_sync_decimator : public gr_sync_block
{
 private:
  unsigned      d_decimation;

 protected:
  gr_sync_decimator (void){} //allows pure virtual interface sub-classes
  gr_sync_decimator (const std::string &name,
                     gr_io_signature_sptr input_signature,
                     gr_io_signature_sptr output_signature,
                     unsigned decimation);
 public:

  unsigned decimation () const { return d_decimation; }
  void set_decimation (unsigned decimation)
  {
    d_decimation = decimation;
    set_relative_rate (1.0 / decimation);
  }

  // gr_sync_decimator overrides these to assist work
  void forecast (int noutput_items, gr_vector_int &ninput_items_required);
  int  general_work (int noutput_items,
                     gr_vector_int &ninput_items,
                     gr_vector_const_void_star &input_items,
                     gr_vector_void_star &output_items);

  // derived classes should override work

  int fixed_rate_ninput_to_noutput(int ninput);
  int fixed_rate_noutput_to_ninput(int noutput);
};


#endif /* INCLUDED_GR_SYNC_DECIMATOR_H */