oscope_guts.cc

/* -*- c++ -*- */
/*
 * Copyright 2003,2005,2013 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.
 */

#ifdef HAVE_CONFIG_H
#include <config.h>
#endif

#include <gnuradio/wxgui/oscope_guts.h>
#include <stdexcept>
#include <stdio.h>
#include <algorithm>
#include <unistd.h>
#include <math.h>
#include <assert.h>

namespace gr {
  namespace wxgui {
    
    /*
     * Bad performance if it's large, and flaky triggering if it's too small
     */
    static const int OUTPUT_RECORD_SIZE = 1024;  // Must be power of 2

    /*
     * For (slow-updated) STRIPCHART triggering, we make the record
     * size larger, since we potentially want to be able to "see"
     * hours of data. This works as long as the update rates to a
     * STRIPCHART are low, which they generally are--that's rather
     * what a stripchart is all about!
     */
    static const int SCHART_MULT = 8;


    static inline int
    wrap_bi(int buffer_index, int mx)                // wrap buffer index
    {
      return buffer_index & (mx - 1);
    }

    static inline int
    incr_bi(int buffer_index, int mx)                // increment buffer index
    {
      return wrap_bi(buffer_index + 1, mx);
    }

    static inline int
    decr_bi(int buffer_index, int mx)                // decrement buffer index
    {
      return wrap_bi(buffer_index - 1, mx);
    }

    oscope_guts::oscope_guts(double sample_rate, msg_queue::sptr msgq)
      : d_nchannels(1),
    d_msgq(msgq),
    d_trigger_mode(TRIG_MODE_AUTO),
    d_trigger_slope(TRIG_SLOPE_POS),
    d_trigger_channel(0),
    d_sample_rate(sample_rate),
    d_update_rate(20),
    d_trigger_level(0),
    d_obi(0),
    d_state(HOLD_OFF),
    d_decimator_count(0),
    d_decimator_count_init(1),
    d_hold_off_count(0),
    d_hold_off_count_init(OUTPUT_RECORD_SIZE/2-1),
    d_pre_trigger_count(0),
    d_post_trigger_count(0),
    d_post_trigger_count_init(OUTPUT_RECORD_SIZE/2)
    {
      for(int i = 0; i < MAX_CHANNELS; i++)
        d_buffer[i] = 0;

      for(int i = 0; i < MAX_CHANNELS; i++) {
        d_buffer[i] = new float[OUTPUT_RECORD_SIZE*SCHART_MULT];
        for(int j = 0; j < OUTPUT_RECORD_SIZE*SCHART_MULT; j++)
          d_buffer[i][j] = 0.0;
      }

      // be sure buffer is full before first write
      enter_hold_off();
      update_rate_or_decimation_changed();
    }

    oscope_guts::~oscope_guts()
    {
      for(int i = 0; i < MAX_CHANNELS; i++)
        delete [] d_buffer[i];
    }

    // MANIPULATORS
    void
    oscope_guts::process_sample(const float *channel_data)
    {
      d_decimator_count--;
      if(d_decimator_count > 0)
        return;

      d_decimator_count = d_decimator_count_init;

      if(d_trigger_mode != TRIG_MODE_STRIPCHART) {
        for(int i = 0; i < d_nchannels; i++)
          d_buffer[i][d_obi] = channel_data[i];  // copy data into buffer

        switch(d_state) {
        case HOLD_OFF:
          d_hold_off_count--;
          if(d_hold_off_count <= 0)
            enter_look_for_trigger ();
          break;

        case LOOK_FOR_TRIGGER:
          if(found_trigger())
            enter_post_trigger();
          break;

        case POST_TRIGGER:
          d_post_trigger_count--;
          if(d_post_trigger_count <= 0) {
            write_output_records();
            enter_hold_off();
          }
          break;

        default:
          assert(0);
        }

        d_obi = incr_bi(d_obi, OUTPUT_RECORD_SIZE);
      }
      else {
        for(int i = 0; i < d_nchannels; i++) {
          for(int j = (OUTPUT_RECORD_SIZE*SCHART_MULT)-1; j > 0; j--) {
            d_buffer[i][j] = d_buffer[i][j-1];
          }
          d_buffer[i][0] = channel_data[i];
        }
        d_trigger_off = 0;
        write_output_records();
      }
    }

    /*
     * Functions called on state entry
     */

    void
    oscope_guts::enter_hold_off()
    {
      d_state = HOLD_OFF;
      d_hold_off_count = d_hold_off_count_init;
    }

    void
    oscope_guts::enter_look_for_trigger()
    {
      d_pre_trigger_count = 0;
      d_state = LOOK_FOR_TRIGGER;
    }

    void
    oscope_guts::enter_post_trigger()
    {
      d_state = POST_TRIGGER;
      d_post_trigger_count = d_post_trigger_count_init;
      //ensure that the trigger offset is no more than than half a sample
      if(d_trigger_off > .5)
        d_trigger_off -= 1;
      else
        d_post_trigger_count--;
    }

    // ----------------------------------------------------------------
    // returns true if trigger found

    bool
    oscope_guts::found_trigger()
    {
      int mx = d_trigger_mode == TRIG_MODE_STRIPCHART ? OUTPUT_RECORD_SIZE*SCHART_MULT :
        OUTPUT_RECORD_SIZE;

      float prev_sample = d_buffer[d_trigger_channel][decr_bi(d_obi, mx)];
      float new_sample = d_buffer[d_trigger_channel][d_obi];

      switch(d_trigger_mode) {

      case TRIG_MODE_AUTO: //too many samples without a trigger
        d_pre_trigger_count++;
        if(d_pre_trigger_count > OUTPUT_RECORD_SIZE/2)
          return true;

      case TRIG_MODE_NORM: //look for trigger
        switch(d_trigger_slope) {

        case TRIG_SLOPE_POS: //trigger point in pos slope?
          if(new_sample < d_trigger_level || prev_sample >= d_trigger_level)
            return false;
          break;

        case TRIG_SLOPE_NEG: //trigger point in neg slope?
          if(new_sample > d_trigger_level || prev_sample <= d_trigger_level)
            return false;
          break;
        }

        //calculate the trigger offset in % sample
        d_trigger_off = (d_trigger_level - prev_sample)/(new_sample - prev_sample);
        return true;

      case TRIG_MODE_FREE: //free run mode, always trigger
        d_trigger_off = 0;
        return true;

      default:
        assert(0);
        return false;
      }
    }

    // ----------------------------------------------------------------
    // write output records (duh!)

    void
    oscope_guts::write_output_records()
    {
      int mx;

      mx = d_trigger_mode == TRIG_MODE_STRIPCHART ?
        OUTPUT_RECORD_SIZE*SCHART_MULT : OUTPUT_RECORD_SIZE;

      // if the output queue if full, drop the data like its hot.
      if(d_msgq->full_p())
        return;
      // Build a message to hold the output records
      message::sptr msg =
        message::make(0,                           // msg type
                        d_nchannels,                 // arg1 for other side
                        mx,                          // arg2 for other side
                        ((d_nchannels * mx) + 1) * sizeof(float)); // sizeof payload

      float *out = (float *)msg->msg();        // get pointer to raw message buffer

      for(int ch = 0; ch < d_nchannels; ch++) {
        // note that d_obi + 1 points at the oldest sample in the buffer
        for(int i = 0; i < mx; i++) {
          out[i] = d_buffer[ch][wrap_bi(d_obi + 1 + i, mx)];
        }
        out += mx;
      }
      //Set the last sample as the trigger offset:
      //  The non gl scope sink will not look at this last sample.
      //  The gl scope sink will use this last sample as an offset.
      out[0] = d_trigger_off;
      d_msgq->handle(msg);                // send the msg
    }

    // ----------------------------------------------------------------

    bool
    oscope_guts::set_update_rate(double update_rate)
    {
      d_update_rate = std::min(std::max (1./10., update_rate), d_sample_rate);
      update_rate_or_decimation_changed();
      return true;
    }

    bool
    oscope_guts::set_decimation_count(int decimator_count)
    {
      decimator_count = std::max(1, decimator_count);
      d_decimator_count_init = decimator_count;
      update_rate_or_decimation_changed();
      return true;
    }

    bool
    oscope_guts::set_sample_rate(double sample_rate)
    {
      d_sample_rate = sample_rate;
      return set_update_rate(update_rate());
    }

    void
    oscope_guts::update_rate_or_decimation_changed()
    {
      d_hold_off_count_init =
        (int)rint(d_sample_rate / d_update_rate / d_decimator_count_init);
    }

    bool
    oscope_guts::set_trigger_channel(int channel)
    {
      if(channel >= 0 && channel < d_nchannels) {
        d_trigger_channel = channel;
        trigger_changed ();
        return true;
      }

      return false;
    }

    bool
    oscope_guts::set_trigger_mode(trigger_mode mode)
    {
      d_trigger_mode = mode;
      trigger_changed();
      return true;
    }

    bool
    oscope_guts::set_trigger_slope(trigger_slope slope)
    {
      d_trigger_slope = slope;
      trigger_changed();
      return true;
    }

    bool
    oscope_guts::set_trigger_level(double trigger_level)
    {
      d_trigger_level = trigger_level;
      trigger_changed();
      return true;
    }

    bool
    oscope_guts::set_trigger_level_auto()
    {
      // find the level 1/2 way between the min and the max

      float min_v = d_buffer[d_trigger_channel][0];
      float max_v = d_buffer[d_trigger_channel][0];

      for(int i = 1; i < OUTPUT_RECORD_SIZE; i++) {
        min_v = std::min (min_v, d_buffer[d_trigger_channel][i]);
        max_v = std::max (max_v, d_buffer[d_trigger_channel][i]);
      }
      return set_trigger_level((min_v + max_v) * 0.5);
    }

    bool
    oscope_guts::set_num_channels(int nchannels)
    {
      if(nchannels > 0 && nchannels <= MAX_CHANNELS) {
        d_nchannels = nchannels;
        return true;
      }
      return false;
    }

    void
    oscope_guts::trigger_changed()
    {
      enter_look_for_trigger();
    }

    // ACCESSORS

    int
    oscope_guts::num_channels() const
    {
      return d_nchannels;
    }

    double
    oscope_guts::sample_rate() const
    {
      return d_sample_rate;
    }

    double
    oscope_guts::update_rate() const
    {
      return d_update_rate;
    }

    int
    oscope_guts::get_decimation_count() const
    {
      return d_decimator_count_init;
    }

    int
    oscope_guts::get_trigger_channel() const
    {
      return d_trigger_channel;
    }

    trigger_mode
    oscope_guts::get_trigger_mode() const
    {
      return d_trigger_mode;
    }

    trigger_slope
    oscope_guts::get_trigger_slope() const
    {
      return d_trigger_slope;
    }

    double
    oscope_guts::get_trigger_level() const
    {
      return d_trigger_level;
    }

    int
    oscope_guts::get_samples_per_output_record() const
    {
      int mx;

      mx = OUTPUT_RECORD_SIZE;
      if(d_trigger_mode == TRIG_MODE_STRIPCHART) {
        mx = OUTPUT_RECORD_SIZE*SCHART_MULT;
      }
      return mx;
    }

  } /* namespace wxgui */
} /* namespace gr */