Logo Search packages:      
Sourcecode: ardour version File versions  Download package

source.cc

/*
    Copyright (C) 2000 Paul Davis 

    This program 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 2 of the License, or
    (at your option) any later version.

    This program 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 this program; if not, write to the Free Software
    Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.

    $Id: source.cc,v 1.57 2006/02/05 00:16:47 essej Exp $
*/

#include <sys/stat.h>
#include <unistd.h>
#include <fcntl.h>
#include <poll.h>
#include <float.h>
#include <cerrno>
#include <ctime>
#include <cmath>
#include <iomanip>
#include <algorithm>

#include <pbd/lockmonitor.h>
#include <pbd/xml++.h>
#include <pbd/pthread_utils.h>

#include <ardour/source.h>
#include <ardour/filesource.h>
#include <ardour/sndfilesource.h>

#include "i18n.h"

using std::min;
using std::max;

using namespace ARDOUR;
using namespace PBD;

SigC::Signal1<void,Source *> Source::SourceCreated;
pthread_t                    Source::peak_thread;
bool                         Source::have_peak_thread = false;
vector<Source*>              Source::pending_peak_sources;
PBD::Lock                    Source::pending_peak_sources_lock;
int                          Source::peak_request_pipe[2];

bool Source::_build_missing_peakfiles = false;
bool Source::_build_peakfiles = false;

Source::Source (bool announce)
{
      _id = ARDOUR::new_id();
      _use_cnt = 0;
      _peaks_built = false;
      next_peak_clear_should_notify = true;
      peakfile = -1;
      _timestamp = 0;
      _read_data_count = 0;
      _write_data_count = 0;
}

Source::Source (const XMLNode& node) 
{
      _use_cnt = 0;
      _peaks_built = false;
      next_peak_clear_should_notify = true;
      peakfile = -1;
      _timestamp = 0;
      _read_data_count = 0;
      _write_data_count = 0;

      if (set_state (node)) {
            throw failed_constructor();
      }
}

Source::~Source ()
{
      if (peakfile >= 0) {
            close (peakfile);
      }
}

XMLNode&
Source::get_state ()
{
      XMLNode *node = new XMLNode ("Source");
      char buf[64];

      node->add_property ("name", _name);
      snprintf (buf, sizeof(buf)-1, "%llu", _id);
      node->add_property ("id", buf);

      if (_timestamp != 0) {
            snprintf (buf, sizeof (buf), "%ld", _timestamp);
            node->add_property ("timestamp", buf);
      }

      if (_captured_for.length()) {
            node->add_property ("captured-for", _captured_for);
      }

      return *node;
}

int
Source::set_state (const XMLNode& node)
{
      const XMLProperty* prop;

      if ((prop = node.property ("name")) != 0) {
            _name = prop->value();
      } else {
            return -1;
      }
      
      if ((prop = node.property ("id")) != 0) {
            sscanf (prop->value().c_str(), "%llu", &_id);
      } else {
            return -1;
      }

      if ((prop = node.property ("timestamp")) != 0) {
            sscanf (prop->value().c_str(), "%ld", &_timestamp);
      }

      if ((prop = node.property ("captured-for")) != 0) {
            _captured_for = prop->value();
      }

      return 0;
}

/***********************************************************************
  PEAK FILE STUFF
 ***********************************************************************/

void*
Source::peak_thread_work (void* arg)
{
      PBD::ThreadCreated (pthread_self(), X_("Peak"));
      struct pollfd pfd[1];

      LockMonitor lm (pending_peak_sources_lock, __LINE__, __FILE__);

      while (true) {

            pfd[0].fd = peak_request_pipe[0];
            pfd[0].events = POLLIN|POLLERR|POLLHUP;

            pthread_mutex_unlock (pending_peak_sources_lock.mutex());

            if (poll (pfd, 1, -1) < 0) {

                  if (errno == EINTR) {
                        pthread_mutex_lock (pending_peak_sources_lock.mutex());
                        continue;
                  }
                  
                  error << compose (_("poll on peak request pipe failed (%1)"),
                                strerror (errno))
                        << endmsg;
                  break;
            }

            if (pfd[0].revents & ~POLLIN) {
                  error << _("Error on peak thread request pipe") << endmsg;
                  break;
            }

            if (pfd[0].revents & POLLIN) {

                  char req;
                  
                  /* empty the pipe of all current requests */

                  while (1) {
                        size_t nread = ::read (peak_request_pipe[0], &req, sizeof (req));

                        if (nread == 1) {
                              switch ((PeakRequest::Type) req) {
                              
                              case PeakRequest::Build:
                                    break;
                                    
                              case PeakRequest::Quit:
                                    pthread_exit_pbd (0);
                                    /*NOTREACHED*/
                                    break;
                                    
                              default:
                                    break;
                              }

                        } else if (nread == 0) {
                              break;
                        } else if (errno == EAGAIN) {
                              break;
                        } else {
                              fatal << _("Error reading from peak request pipe") << endmsg;
                              /*NOTREACHED*/
                        }
                  }
            }

            pthread_mutex_lock (pending_peak_sources_lock.mutex());

            while (!pending_peak_sources.empty()) {

                  Source* s = pending_peak_sources.front();
                  pending_peak_sources.erase (pending_peak_sources.begin());

                  pthread_mutex_unlock (pending_peak_sources_lock.mutex());
                  s->build_peaks();
                  pthread_mutex_lock (pending_peak_sources_lock.mutex());
            }
      }

      pthread_exit_pbd (0);
      /*NOTREACHED*/
      return 0;
}

int
Source::start_peak_thread ()
{
      if (!_build_peakfiles) {
            return 0;
      }

      if (pipe (peak_request_pipe)) {
            error << compose(_("Cannot create transport request signal pipe (%1)"), strerror (errno)) << endmsg;
            return -1;
      }

      if (fcntl (peak_request_pipe[0], F_SETFL, O_NONBLOCK)) {
            error << compose(_("UI: cannot set O_NONBLOCK on peak request pipe (%1)"), strerror (errno)) << endmsg;
            return -1;
      }

      if (fcntl (peak_request_pipe[1], F_SETFL, O_NONBLOCK)) {
            error << compose(_("UI: cannot set O_NONBLOCK on peak request pipe (%1)"), strerror (errno)) << endmsg;
            return -1;
      }

      if (pthread_create_and_store ("peak file builder", &peak_thread, 0, peak_thread_work, 0)) {
            error << _("Source: could not create peak thread") << endmsg;
            return -1;
      }

      have_peak_thread = true;
      return 0;
}

void
Source::stop_peak_thread ()
{
      if (!have_peak_thread) {
            return;
      }

      void* status;

      char c = (char) PeakRequest::Quit;
      ::write (peak_request_pipe[1], &c, 1);
      pthread_join (peak_thread, &status);
}

void 
Source::queue_for_peaks (Source& source)
{
      if (have_peak_thread) {

            LockMonitor lm (pending_peak_sources_lock, __LINE__, __FILE__);

            source.next_peak_clear_should_notify = true;

            if (find (pending_peak_sources.begin(),
                    pending_peak_sources.end(),
                    &source) == pending_peak_sources.end()) {
                  pending_peak_sources.push_back (&source);
            }

            char c = (char) PeakRequest::Build;
            ::write (peak_request_pipe[1], &c, 1);
      }
}

void Source::clear_queue_for_peaks ()
{
      /* this is done to cancel a group of running peak builds */
      if (have_peak_thread) {
            LockMonitor lm (pending_peak_sources_lock, __LINE__, __FILE__);
            pending_peak_sources.clear ();
      }
}


bool
Source::peaks_ready (SigC::Slot0<void> the_slot) const
{
      bool ret;
      LockMonitor lm (_lock, __LINE__, __FILE__);

      /* check to see if the peak data is ready. if not
         connect the slot while still holding the lock.
      */

      if (!(ret = _peaks_built)) {
            PeaksReady.connect (the_slot);
      }

      return ret;
}

int
Source::initialize_peakfile (bool newfile, string audio_path)
{
      struct stat statbuf;

      peakpath = peak_path (audio_path);

      if (newfile) {

            if (!_build_peakfiles) {
                  return 0;
            }

            _peaks_built = false;

      } else {

            if (stat (peakpath.c_str(), &statbuf)) {
                  if (errno != ENOENT) {
                        /* it exists in the peaks dir, but there is some kind of error */
                        
                        error << compose(_("Source: cannot stat peakfile \"%1\""), peakpath) << endmsg;
                        return -1;
                  }

                  /* older sessions stored peaks in the same directory
                     as the audio. so check there as well.
                  */
                  
                  string oldpeakpath = old_peak_path (audio_path);
                  
                  if (stat (oldpeakpath.c_str(), &statbuf)) {
                        
                        if (errno == ENOENT) {

                              statbuf.st_size = 0;

                        } else {
                              
                              /* it exists in the audio dir , but there is some kind of error */
                              
                              error << compose(_("Source: cannot stat peakfile \"%1\" or \"%2\""), peakpath, oldpeakpath) << endmsg;
                              return -1;
                        }
                        
                  } else {

                        /* we found it in the sound dir, where they lived once upon a time, in a land ... etc. */

                        peakpath = oldpeakpath;
                  }

            } else {
                  
                  /* we found it in the peaks dir */
            }
            
            if (statbuf.st_size == 0) {
                  _peaks_built = false;
            } else {
                  // Check if the audio file has changed since the peakfile was built.
                  struct stat stat_file;
                  int err = stat (audio_path.c_str(), &stat_file);
                  
                  if (!err && stat_file.st_mtime > statbuf.st_mtime){
                        _peaks_built = false;
                  } else {
                        _peaks_built = true;
                  }
            }
      }

      if ((peakfile = ::open (peakpath.c_str(), O_RDWR|O_CREAT, 0664)) < 0) {
            error << compose(_("Source: cannot open peakpath \"%1\" (%2)"), peakpath, strerror (errno)) << endmsg;
            return -1;
      }

      if (!newfile && !_peaks_built && _build_missing_peakfiles && _build_peakfiles) {
            build_peaks_from_scratch ();
      } 

      return 0;
}

int 
Source::read_peaks (PeakData *peaks, jack_nframes_t npeaks, jack_nframes_t start, jack_nframes_t cnt, double samples_per_visual_peak) const
{
      LockMonitor lm (_lock, __LINE__, __FILE__);
      double scale;
      double expected_peaks;
      PeakData::PeakDatum xmax;
      PeakData::PeakDatum xmin;
      int32_t to_read;
      ssize_t nread;
      jack_nframes_t zero_fill = 0;
      int ret = -1;
      PeakData* staging = 0;
      Sample* raw_staging = 0;

      expected_peaks = (cnt / (double) frames_per_peak);
      scale = npeaks/expected_peaks;

#if 0
      cerr << "======>RP: npeaks = " << npeaks 
           << " start = " << start 
           << " cnt = " << cnt 
           << " len = " << _length 
           << "   samples_per_visual_peak =" << samples_per_visual_peak 
           << " expected was " << expected_peaks << " ... scale = " << scale
           << " PD ptr = " << peaks
           <<endl;
      
#endif

      /* fix for near-end-of-file conditions */

      if (cnt > _length - start) {
            // cerr << "too close to end @ " << _length << " given " << start << " + " << cnt << endl;
            cnt = _length - start;
            jack_nframes_t old = npeaks;
            npeaks = min ((jack_nframes_t) floor (cnt / samples_per_visual_peak), npeaks);
            zero_fill = old - npeaks;
      }

      // cerr << "actual npeaks = " << npeaks << " zf = " << zero_fill << endl;
      
      if (npeaks == cnt) {

            // cerr << "RAW DATA\n";
            
            /* no scaling at all, just get the sample data and duplicate it for
               both max and min peak values.
            */

            Sample* raw_staging = new Sample[cnt];
            
            if (read_unlocked (raw_staging, start, cnt) != cnt) {
                  error << _("cannot read sample data for unscaled peak computation") << endmsg;
                  return -1;
            }

            for (jack_nframes_t i = 0; i < npeaks; ++i) {
                  peaks[i].max = raw_staging[i];
                  peaks[i].min = raw_staging[i];
            }

            delete [] raw_staging;
            
            return 0;
      }

      if (scale == 1.0) {

            // cerr << "DIRECT PEAKS\n";
            
            off_t first_peak_byte = (start / frames_per_peak) * sizeof (PeakData);
            jack_nframes_t peaks_read = 0;
            jack_nframes_t npeaks_toread = npeaks;
            
            while (peaks_read < npeaks) {
                  if ((nread = ::pread (peakfile, peaks + peaks_read, sizeof (PeakData)* npeaks_toread, first_peak_byte)) != (ssize_t) (sizeof (PeakData) * npeaks_toread)) {
                        if (nread <= 0) {
                              cerr << "Source["
                                   << _name
                                   << "]: cannot read peaks from peakfile! (read only " 
                                   << peaks_read
                                   << " not " 
                                   << npeaks_toread
                                   << "at sample " 
                                   << start
                                   << " = byte "
                                   << first_peak_byte
                                   << ')'
                                   << endl;
                              return -1;
                        }
                        else {
                              // returned less than expected, this can happen if we are near the end of the file
                              // and some write activity is still occurring
                              
                        }
                  }
                  peaks_read += nread / sizeof(PeakData);
                  npeaks_toread -= nread / sizeof(PeakData);
                  first_peak_byte += nread;
            }

            if (zero_fill) {
                  memset (&peaks[npeaks], 0, sizeof (PeakData) * zero_fill);
            }

            return 0;
      }


      jack_nframes_t tnp;

      if (scale < 1.0) {

            // cerr << "DOWNSAMPLE\n";

            /* the caller wants:

                - more frames-per-peak (lower resolution) than the peakfile, or to put it another way,
                    - less peaks than the peakfile holds for the same range

                So, read a block into a staging area, and then downsample from there.

                to avoid confusion, I'll refer to the requested peaks as visual_peaks and the peakfile peaks as stored_peaks  
            */

            const uint32_t chunksize = (uint32_t) min (expected_peaks, 4096.0);
            
            staging = new PeakData[chunksize];
            
            /* compute the rounded up frame position  */
      
            jack_nframes_t current_frame = start;
            jack_nframes_t current_stored_peak = (jack_nframes_t) ceil (current_frame / (double) frames_per_peak);
            uint32_t       next_visual_peak  = (uint32_t) ceil (current_frame / samples_per_visual_peak);
            double         next_visual_peak_frame = next_visual_peak * samples_per_visual_peak;
            uint32_t       stored_peak_before_next_visual_peak = (jack_nframes_t) next_visual_peak_frame / frames_per_peak;
            uint32_t       nvisual_peaks = 0;
            uint32_t       stored_peaks_read = 0;
            uint32_t       i = 0;

            /* handle the case where the initial visual peak is on a pixel boundary */

            current_stored_peak = min (current_stored_peak, stored_peak_before_next_visual_peak);

            while (nvisual_peaks < npeaks) {

                  if (i == stored_peaks_read) {

                        uint32_t       start_byte = current_stored_peak * sizeof(PeakData);
                        tnp = min ((_length/frames_per_peak - current_stored_peak), (jack_nframes_t) expected_peaks);
                        to_read = min (chunksize, tnp);

                        jack_nframes_t peaks_read = 0;
                        jack_nframes_t npeaks_toread = to_read;
                        
                        while (peaks_read < (jack_nframes_t) to_read) {
                        
                              if ((nread = ::pread (peakfile, staging + peaks_read, sizeof (PeakData) * npeaks_toread, start_byte))
                                  != (ssize_t) (sizeof (PeakData) * npeaks_toread)) {
                                    if (nread < 0) {
                                        cerr << "Source["
                                        << _name
                                        << "]: cannot read peak data from peakfile ("
                                        << peaks_read
                                        << " peaks instead of "
                                        << npeaks_toread
                                        << ") ("
                                        << strerror (errno)
                                        << ')'
                                        << " at start_byte = " << start_byte 
                                        << " _length = " << _length
                                        << " expected maxpeaks = " << (_length - current_frame)/frames_per_peak
                                        << " npeaks was " << npeaks
                                        << endl;
                                        goto out;
                                    }
                                    else if (nread == 0) {
                                        cerr << "Source["
                                        << _name
                                        << "]: cannot read all expected peak data from peakfile ("
                                        << nread
                                        << " peaks instead of "
                                        << to_read
                                        << ")"
                                        << " at start_byte = " << start_byte 
                                        << " _length = " << _length
                                        << " expected maxpeaks = " << (_length - current_frame)/frames_per_peak
                                        << " npeaks was " << npeaks
                                        << endl;
                                        goto out;
                                    }
                                    else {
                                          // could be a legitimate short read at this point
                                    }
                              }

                              peaks_read += nread / sizeof(PeakData);
                              npeaks_toread -= nread / sizeof(PeakData);
                              start_byte += nread;
                        }

                        i = 0;
                        stored_peaks_read = peaks_read;
                  }

                  xmax = -1.0;
                  xmin = 1.0;

                  while ((i < stored_peaks_read) && (current_stored_peak <= stored_peak_before_next_visual_peak)) {

                        xmax = max (xmax, staging[i].max);
                        xmin = min (xmin, staging[i].min);
                        ++i;
                        ++current_stored_peak;
                        --expected_peaks;
                  }

                  peaks[nvisual_peaks].max = xmax;
                  peaks[nvisual_peaks].min = xmin;
                  ++nvisual_peaks;
                  ++next_visual_peak;

                  //next_visual_peak_frame = min ((next_visual_peak * samples_per_visual_peak), (next_visual_peak_frame+samples_per_visual_peak) );
                  next_visual_peak_frame =  min ((double) start+cnt, (next_visual_peak_frame+samples_per_visual_peak) );
                  stored_peak_before_next_visual_peak = (uint32_t) next_visual_peak_frame / frames_per_peak; 
            }

            if (zero_fill) {
                  memset (&peaks[npeaks], 0, sizeof (PeakData) * zero_fill);
            }
            
            ret = 0;

      } else {
            
            // cerr << "UPSAMPLE\n";

            /* the caller wants 

                 - less frames-per-peak (more resolution)
                 - more peaks than stored in the Peakfile

               So, fetch data from the raw source, and generate peak
               data on the fly.
            */

            jack_nframes_t frames_read = 0;
            jack_nframes_t current_frame = start;
            jack_nframes_t i = 0;
            jack_nframes_t nvisual_peaks = 0;
            jack_nframes_t chunksize = (jack_nframes_t) min (cnt, (jack_nframes_t) 4096);
            raw_staging = new Sample[chunksize];

            jack_nframes_t frame_pos = start;
            double pixel_pos = floor (frame_pos / samples_per_visual_peak);
            double next_pixel_pos = ceil (frame_pos / samples_per_visual_peak);
            double pixels_per_frame = 1.0 / samples_per_visual_peak;

            xmin = 1.0;
            xmax = -1.0;

            while (nvisual_peaks < npeaks) {

                  if (i == frames_read) {
                        
                        to_read = min (chunksize, (_length - current_frame));
                        
                        if ((frames_read = read_unlocked (raw_staging, current_frame, to_read)) == 0) {
                              error << compose(_("Source[%1]: peak read - cannot read %2 samples at offset %3")
                                           , _name, to_read, current_frame) 
                                    << endmsg;
                              goto out;
                        }

                        i = 0;
                  }
                  
                  xmax = max (xmax, raw_staging[i]);
                  xmin = min (xmin, raw_staging[i]);
                  ++i;
                  ++current_frame;
                  pixel_pos += pixels_per_frame;

                  if (pixel_pos >= next_pixel_pos) {

                        peaks[nvisual_peaks].max = xmax;
                        peaks[nvisual_peaks].min = xmin;
                        ++nvisual_peaks;
                        xmin = 1.0;
                        xmax = -1.0;

                        next_pixel_pos = ceil (pixel_pos + 0.5);
                  }
            }
            
            if (zero_fill) {
                  memset (&peaks[npeaks], 0, sizeof (PeakData) * zero_fill);
            }

            ret = 0;
      }

  out:
      if (staging) {
            delete [] staging;
      } 

      if (raw_staging) {
            delete [] raw_staging;
      }

      return ret;
}

#undef DEBUG_PEAK_BUILD

int
Source::build_peaks ()
{
      vector<PeakBuildRecord*> built;
      int status = -1;
      bool pr_signal = false;
      list<PeakBuildRecord*> copy;

      {
            LockMonitor lm (_lock, __LINE__, __FILE__);
            copy = pending_peak_builds;
            pending_peak_builds.clear ();
      }
            

#ifdef DEBUG_PEAK_BUILD
      cerr << "build peaks with " << pending_peak_builds.size() << " requests pending\n";
#endif            

      for (list<PeakBuildRecord *>::iterator i = copy.begin(); i != copy.end(); ++i) {
            
            if ((status = do_build_peak ((*i)->frame, (*i)->cnt)) != 0) { 
                  unlink (peakpath.c_str());
                  break;
            }
            built.push_back (new PeakBuildRecord (*(*i)));
            delete *i;
      }

      { 
            LockMonitor lm (_lock, __LINE__, __FILE__);

            if (status == 0) {
                  _peaks_built = true;
                  
                  if (next_peak_clear_should_notify) {
                        next_peak_clear_should_notify = false;
                        pr_signal = true;
                  }
            }
      }

      if (status == 0) {
            for (vector<PeakBuildRecord *>::iterator i = built.begin(); i != built.end(); ++i) {
                  PeakRangeReady ((*i)->frame, (*i)->cnt); /* EMIT SIGNAL */
                  delete *i;
            }

            if (pr_signal) {
                  PeaksReady (); /* EMIT SIGNAL */
            }
      }

      return status;
}

int
Source::do_build_peak (jack_nframes_t first_frame, jack_nframes_t cnt)
{
      jack_nframes_t current_frame;
      Sample buf[frames_per_peak];
      Sample xmin, xmax;
      uint32_t  peaki;
      PeakData* peakbuf;
      jack_nframes_t frames_read;
      jack_nframes_t frames_to_read;
      off_t first_peak_byte;
      int ret = -1;

#ifdef DEBUG_PEAK_BUILD
      cerr << pthread_self() << ": " << _name << ": building peaks for " << first_frame << " to " << first_frame + cnt - 1 << endl;
#endif

      first_peak_byte = (first_frame / frames_per_peak) * sizeof (PeakData);

#ifdef DEBUG_PEAK_BUILD
      cerr << "seeking to " << first_peak_byte << " before writing new peak data\n";
#endif

      current_frame = first_frame;
      peakbuf = new PeakData[(cnt/frames_per_peak)+1];
      peaki = 0;

      while (cnt) {

            frames_to_read = min (frames_per_peak, cnt);

            if ((frames_read = read_unlocked (buf, current_frame, frames_to_read)) != frames_to_read) {
                  error << compose(_("%1: could not write read raw data for peak computation (%2)"), _name, strerror (errno)) << endmsg;
                  goto out;
            }

            xmin = buf[0];
            xmax = buf[0];

            for (jack_nframes_t n = 1; n < frames_read; ++n) {
                  xmax = max (xmax, buf[n]);
                  xmin = min (xmin, buf[n]);

//                if (current_frame < frames_read) {
//                      cerr << "sample = " << buf[n] << " max = " << xmax << " min = " << xmin << " max of 2 = " << max (xmax, buf[n]) << endl;
//                }
            }

            peakbuf[peaki].max = xmax;
            peakbuf[peaki].min = xmin;
            peaki++;

            current_frame += frames_read;
            cnt -= frames_read;
      }

      if (::pwrite (peakfile, peakbuf, sizeof (PeakData) * peaki, first_peak_byte) != (ssize_t) (sizeof (PeakData) * peaki)) {
            error << compose(_("%1: could not write peak file data (%2)"), _name, strerror (errno)) << endmsg;
            goto out;
      }

      ret = 0;

  out:
      delete [] peakbuf;
      return ret;
}

void
Source::build_peaks_from_scratch ()
{
      LockMonitor lp (_lock, __LINE__, __FILE__); 

      next_peak_clear_should_notify = true;
      pending_peak_builds.push_back (new PeakBuildRecord (0, _length));
      queue_for_peaks (*this);
}

bool
Source::file_changed (string path)
{
      struct stat stat_file;
      struct stat stat_peak;

      int e1 = stat (path.c_str(), &stat_file);
      int e2 = stat (peak_path(path).c_str(), &stat_peak);
      
      if (!e1 && !e2 && stat_file.st_mtime > stat_peak.st_mtime){
            return true;
      } else {
            return false;
      }
}

void
Source::use ()
{
      _use_cnt++;
}

void
Source::release ()
{
      if (_use_cnt) --_use_cnt;
}

Generated by  Doxygen 1.6.0   Back to index