silentfilesource.h

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/*
 * Copyright (C) 2007-2017 Paul Davis <paul@linuxaudiosystems.com>
 * Copyright (C) 2008-2011 David Robillard <d@drobilla.net>
 * Copyright (C) 2009-2010 Carl Hetherington <carl@carlh.net>
 * Copyright (C) 2013 John Emmas <john@creativepost.co.uk>
 * Copyright (C) 2016-2018 Robin Gareus <robin@gareus.org>
 *
 * 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.,
 * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
 */
 
#ifndef __ardour_silentfilesource_h__
#define __ardour_silentfilesource_h__
 
#include <cstring>
#include "ardour/audiofilesource.h"
 
namespace ARDOUR {
 
class LIBARDOUR_API SilentFileSource : public AudioFileSource {
public:
        int update_header (samplepos_t /*when*/, struct tm&, time_t) { return 0; }
        int flush_header () { return 0; }
        float sample_rate () const { return _sample_rate; }
 
        void set_length (samplecnt_t len) { _length = timecnt_t (len); }
        void flush () {}
 
        bool can_be_analysed() const { return false; }
 
        bool clamped_at_unity() const { return false; }
 
protected:
        void close() {}
        friend class SourceFactory;
 
        SilentFileSource (Session& s, const XMLNode& x, samplecnt_t len, float srate)
                : Source (s, x)
                , AudioFileSource (s, x, false)
                , _sample_rate(srate)
        {
                _length = timecnt_t (len);
        }
 
        samplecnt_t read_unlocked (Sample *dst, samplepos_t start, samplecnt_t cnt) const {
                cnt = std::min (cnt, std::max<samplecnt_t> (0, _length.samples() - start));
                memset (dst, 0, sizeof (Sample) * cnt);
                return cnt;
        }
 
        samplecnt_t write_unlocked (Sample */*dst*/, samplecnt_t /*cnt*/) { return 0; }
 
        void set_header_natural_position () {}
 
        int read_peaks_with_fpp (PeakData *peaks, samplecnt_t npeaks, samplepos_t /*start*/, samplecnt_t /*cnt*/,
                                 double /*samples_per_pixel*/, samplecnt_t /*fpp*/) const {
                memset (peaks, 0, sizeof (PeakData) * npeaks);
                return 0;
        }
 
        float _sample_rate;
};
 
} // namespace ARDOUR
 
#endif /* __ardour_audiofilesource_h__ */