/*
    Copyright (C) 2006 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.

*/

#include <cstring>
#include <cerrno>
#include <climits>
#include <cstdarg>

#include <pwd.h>
#include <sys/utsname.h>
#include <sys/stat.h>

#include <glibmm/miscutils.h>
#include <pbd/stacktrace.h>

#include <ardour/sndfilesource.h>
#include <ardour/sndfile_helpers.h>
#include <ardour/utils.h>
#include <ardour/version.h>

#include "i18n.h"

using namespace std;
using namespace ARDOUR;
using namespace PBD;
using Glib::ustring;

gain_t* SndFileSource::out_coefficient = 0;
gain_t* SndFileSource::in_coefficient = 0;
nframes_t SndFileSource::xfade_frames = 64;
const AudioFileSource::Flag SndFileSource::default_writable_flags = AudioFileSource::Flag (AudioFileSource::Writable|
											   AudioFileSource::Removable|
											   AudioFileSource::RemovableIfEmpty|
											   AudioFileSource::CanRename);

static void
snprintf_bounded_null_filled (char* target, size_t target_size, const char* fmt, ...)
{
	char buf[target_size+1];
	va_list ap;

	va_start (ap, fmt);
	vsnprintf (buf, target_size+1, fmt, ap);
	va_end (ap);

	memset (target, 0, target_size);
	memcpy (target, buf, target_size);

}

SndFileSource::SndFileSource (Session& s, const XMLNode& node)
	: AudioFileSource (s, node)
{
	init ();

	if (open()) {
		throw failed_constructor ();
	}
}

SndFileSource::SndFileSource (Session& s, ustring path, int chn, Flag flags)
          /* files created this way are never writable or removable */
	: AudioFileSource (s, path, Flag (flags & ~(Writable|Removable|RemovableIfEmpty|RemoveAtDestroy)))
{
	_channel = chn;

	init ();

	if (open()) {
		throw failed_constructor ();
	}
}

SndFileSource::SndFileSource (Session& s, ustring path, SampleFormat sfmt, HeaderFormat hf, nframes_t rate, Flag flags)
	: AudioFileSource (s, path, flags, sfmt, hf)
{
	int fmt = 0;

	init ();

	/* this constructor is used to construct new files, not open
	   existing ones.
	*/

	file_is_new = true;

	switch (hf) {
	case CAF:
		fmt = SF_FORMAT_CAF;
		_flags = Flag (_flags & ~Broadcast);
		break;

	case AIFF:
		fmt = SF_FORMAT_AIFF;
		_flags = Flag (_flags & ~Broadcast);
		break;

	case BWF:
		fmt = SF_FORMAT_WAV;
		_flags = Flag (_flags | Broadcast);
		break;

	case WAVE:
		fmt = SF_FORMAT_WAV;
		_flags = Flag (_flags & ~Broadcast);
		break;

	case WAVE64:
		fmt = SF_FORMAT_W64;
		_flags = Flag (_flags & ~Broadcast);
		break;

	default:
		fatal << string_compose (_("programming error: %1"), X_("unsupported audio header format requested")) << endmsg;
		/*NOTREACHED*/
		break;

	}

	switch (sfmt) {
	case FormatFloat:
		fmt |= SF_FORMAT_FLOAT;
		break;

	case FormatInt24:
		fmt |= SF_FORMAT_PCM_24;
		break;

	case FormatInt16:
		fmt |= SF_FORMAT_PCM_16;
		break;
	}
	
	_info.channels = 1;
	_info.samplerate = rate;
	_info.format = fmt;

	if (open()) {
		throw failed_constructor();
	}

	if (writable() && (_flags & Broadcast)) {

		if (!_broadcast_info) {
			_broadcast_info = new SF_BROADCAST_INFO;
			memset (_broadcast_info, 0, sizeof (*_broadcast_info));
		}
		
		snprintf_bounded_null_filled (_broadcast_info->description, sizeof (_broadcast_info->description), "BWF %s", _name.c_str());
		snprintf_bounded_null_filled (_broadcast_info->originator, sizeof (_broadcast_info->originator), "ardour %d.%d.%d %s", 
					      libardour2_major_version,
					      libardour2_minor_version,
					      libardour2_micro_version,
					      Glib::get_real_name().c_str());
		
		_broadcast_info->version = 1;  
		_broadcast_info->time_reference_low = 0;  
		_broadcast_info->time_reference_high = 0;  
		
		/* XXX do something about this field */
		
		snprintf_bounded_null_filled (_broadcast_info->umid, sizeof (_broadcast_info->umid), "%s", "fnord");
		
		/* coding history is added by libsndfile */

		if (sf_command (sf, SFC_SET_BROADCAST_INFO, _broadcast_info, sizeof (_broadcast_info)) != SF_TRUE) {
			char errbuf[256];
			sf_error_str (0, errbuf, sizeof (errbuf) - 1);
			error << string_compose (_("cannot set broadcast info for audio file %1 (%2); dropping broadcast info for this file"), _path, errbuf) << endmsg;
			_flags = Flag (_flags & ~Broadcast);
			delete _broadcast_info;
			_broadcast_info = 0;
		} 
	} 
}

void 
SndFileSource::init ()
{
	ustring file;

	// lets try to keep the object initalizations here at the top
	xfade_buf = 0;
	sf = 0;
	_broadcast_info = 0;

	if (is_embedded()) {
		_name = _path;
	} else {
		_name = Glib::path_get_basename (_path);
	}

	/* although libsndfile says we don't need to set this,
	   valgrind and source code shows us that we do.
	*/

	memset (&_info, 0, sizeof(_info));

	_capture_start = false;
	_capture_end = false;
	file_pos = 0;

	if (destructive()) {	
		xfade_buf = new Sample[xfade_frames];
		timeline_position = header_position_offset;
	}

	AudioFileSource::HeaderPositionOffsetChanged.connect (mem_fun (*this, &SndFileSource::handle_header_position_change));
}

int
SndFileSource::open ()
{
	if ((sf = sf_open (_path.c_str(), (writable() ? SFM_RDWR : SFM_READ), &_info)) == 0) {
		char errbuf[256];
		sf_error_str (0, errbuf, sizeof (errbuf) - 1);
#ifndef HAVE_COREAUDIO
		/* if we have CoreAudio, we will be falling back to that if libsndfile fails,
		   so we don't want to see this message.
		*/

		error << string_compose(_("SndFileSource: cannot open file \"%1\" for %2 (%3)"), 
					_path, (writable() ? "read+write" : "reading"), errbuf) << endmsg;
#endif
		return -1;
	}

	if (_channel >= _info.channels) {
#ifndef HAVE_COREAUDIO
		error << string_compose(_("SndFileSource: file only contains %1 channels; %2 is invalid as a channel number"), _info.channels, _channel) << endmsg;
#endif
		sf_close (sf);
		sf = 0;
		return -1;
	}

	_length = _info.frames;

	if (!_broadcast_info) {
		_broadcast_info = new SF_BROADCAST_INFO;
		memset (_broadcast_info, 0, sizeof (*_broadcast_info));
	}
	
	bool timecode_info_exists;

	set_timeline_position (get_timecode_info (sf, _broadcast_info, timecode_info_exists));

	if (_length != 0 && !timecode_info_exists) {
		delete _broadcast_info;
		_broadcast_info = 0;
		_flags = Flag (_flags & ~Broadcast);
	}

	if (writable()) {
		sf_command (sf, SFC_SET_UPDATE_HEADER_AUTO, 0, SF_FALSE);
	}

	return 0;
}

SndFileSource::~SndFileSource ()
{
	GoingAway (); /* EMIT SIGNAL */

	if (sf) {
		sf_close (sf);
		sf = 0;

		/* stupid libsndfile updated the headers on close,
		   so touch the peakfile if it exists and has data
		   to make sure its time is as new as the audio
		   file.
		*/

		touch_peakfile ();
	}

	if (_broadcast_info) {
		delete _broadcast_info;
	}

	if (xfade_buf) {
		delete [] xfade_buf;
	}
}

float
SndFileSource::sample_rate () const 
{
	return _info.samplerate;
}

nframes_t
SndFileSource::read_unlocked (Sample *dst, nframes_t start, nframes_t cnt) const
{
	int32_t nread;
	float *ptr;
	uint32_t real_cnt;
	nframes_t file_cnt;

	if (start > _length) {

		/* read starts beyond end of data, just memset to zero */
		
		file_cnt = 0;

	} else if (start + cnt > _length) {
		
		/* read ends beyond end of data, read some, memset the rest */
		
		file_cnt = _length - start;

	} else {
		
		/* read is entirely within data */

		file_cnt = cnt;
	}
	
	if (file_cnt != cnt) {
		nframes_t delta = cnt - file_cnt;
		memset (dst+file_cnt, 0, sizeof (Sample) * delta);
	}

	if (file_cnt) {

		if (sf_seek (sf, (sf_count_t) start, SEEK_SET|SFM_READ) != (sf_count_t) start) {
			char errbuf[256];
			sf_error_str (0, errbuf, sizeof (errbuf) - 1);
			error << string_compose(_("SndFileSource: could not seek to frame %1 within %2 (%3)"), start, _name.substr (1), errbuf) << endmsg;
			return 0;
		}
		
		if (_info.channels == 1) {
			nframes_t ret = sf_read_float (sf, dst, file_cnt);
			_read_data_count = ret * sizeof(float);
			if (ret != file_cnt) {
				char errbuf[256];
				sf_error_str (0, errbuf, sizeof (errbuf) - 1);
				cerr << string_compose(_("SndFileSource: @ %1 could not read %2 within %3 (%4) (len = %5)"), start, file_cnt, _name.substr (1), errbuf, _length) << endl;
			}
			return ret;
		}
	}

	real_cnt = cnt * _info.channels;

	Sample* interleave_buf = get_interleave_buffer (real_cnt);
	
	nread = sf_read_float (sf, interleave_buf, real_cnt);
	ptr = interleave_buf + _channel;
	nread /= _info.channels;
	
	/* stride through the interleaved data */
	
	for (int32_t n = 0; n < nread; ++n) {
		dst[n] = *ptr;
		ptr += _info.channels;
	}

	_read_data_count = cnt * sizeof(float);
		
	return nread;
}

nframes_t 
SndFileSource::write_unlocked (Sample *data, nframes_t cnt)
{
	if (destructive()) {
		return destructive_write_unlocked (data, cnt);
	} else {
		return nondestructive_write_unlocked (data, cnt);
	}
}

nframes_t 
SndFileSource::nondestructive_write_unlocked (Sample *data, nframes_t cnt)
{
	if (!writable()) {
		warning << string_compose (_("attempt to write a non-writable audio file source (%1)"), _path) << endmsg;
		return 0;
	}

	if (_info.channels != 1) {
		fatal << string_compose (_("programming error: %1 %2"), X_("SndFileSource::write called on non-mono file"), _path) << endmsg;
		/*NOTREACHED*/
		return 0;
	}
	
	nframes_t oldlen;
	int32_t frame_pos = _length;

	if (write_float (data, frame_pos, cnt) != cnt) {
		return 0;
	}

	oldlen = _length;
	update_length (oldlen, cnt);

	if (_build_peakfiles) {
		compute_and_write_peaks (data, frame_pos, cnt, false, true);
	}

	_write_data_count = cnt;

	return cnt;
}

nframes_t
SndFileSource::destructive_write_unlocked (Sample* data, nframes_t cnt)
{
	nframes_t old_file_pos;

	if (!writable()) {
		warning << string_compose (_("attempt to write a non-writable audio file source (%1)"), _path) << endmsg;
		return 0;
	}

	if (_capture_start && _capture_end) {

		/* start and end of capture both occur within the data we are writing,
		   so do both crossfades.
		*/

		_capture_start = false;
		_capture_end = false;
		
		/* move to the correct location place */
		file_pos = capture_start_frame - timeline_position;
		
		// split cnt in half
		nframes_t subcnt = cnt / 2;
		nframes_t ofilepos = file_pos;
		
		// fade in
		if (crossfade (data, subcnt, 1) != subcnt) {
			return 0;
		}
		
		file_pos += subcnt;
		Sample * tmpdata = data + subcnt;
		
		// fade out
		subcnt = cnt - subcnt;
		if (crossfade (tmpdata, subcnt, 0) != subcnt) {
			return 0;
		}
		
		file_pos = ofilepos; // adjusted below

	} else if (_capture_start) {

		/* start of capture both occur within the data we are writing,
		   so do the fade in
		*/

		_capture_start = false;
		_capture_end = false;
		
		/* move to the correct location place */
		file_pos = capture_start_frame - timeline_position;

		if (crossfade (data, cnt, 1) != cnt) {
			return 0;
		}
		
	} else if (_capture_end) {

		/* end of capture both occur within the data we are writing,
		   so do the fade out
		*/

		_capture_start = false;
		_capture_end = false;
		
		if (crossfade (data, cnt, 0) != cnt) {
			return 0;
		}

	} else {

		/* in the middle of recording */

		if (write_float (data, file_pos, cnt) != cnt) {
			return 0;
		}
	}

	old_file_pos = file_pos;
	update_length (file_pos, cnt);

	if (_build_peakfiles) {
		compute_and_write_peaks (data, file_pos, cnt, false, true);
	}

	file_pos += cnt;
	
	return cnt;
}

int
SndFileSource::update_header (nframes_t when, struct tm& now, time_t tnow)
{	
	set_timeline_position (when);

	if (_flags & Broadcast) {
		if (setup_broadcast_info (when, now, tnow)) {
			return -1;
		}
	} 

	return flush_header ();
}

int
SndFileSource::flush_header ()
{
	if (!writable() || (sf == 0)) {
		warning << string_compose (_("attempt to flush a non-writable audio file source (%1)"), _path) << endmsg;
		return -1;
	}
	return (sf_command (sf, SFC_UPDATE_HEADER_NOW, 0, 0) != SF_TRUE);
}

int
SndFileSource::setup_broadcast_info (nframes_t when, struct tm& now, time_t tnow)
{
	if (!writable()) {
		warning << string_compose (_("attempt to store broadcast info in a non-writable audio file source (%1)"), _path) << endmsg;
		return -1;
	}

	if (!(_flags & Broadcast)) {
		return 0;
	}

	/* random code is 9 digits */
	
	int random_code = random() % 999999999;
	
	snprintf_bounded_null_filled (_broadcast_info->originator_reference, sizeof (_broadcast_info->originator_reference), "%2s%3s%12s%02d%02d%02d%9d",
				      Config->get_bwf_country_code().c_str(),
				      Config->get_bwf_organization_code().c_str(),
				      bwf_serial_number,
				      now.tm_hour,
				      now.tm_min,
				      now.tm_sec,
				      random_code);
	
	snprintf_bounded_null_filled (_broadcast_info->origination_date, sizeof (_broadcast_info->origination_date), "%4d-%02d-%02d",
				      1900 + now.tm_year,
				      now.tm_mon + 1, // shift range from 0..11 to 1..12
				      now.tm_mday);
	
	snprintf_bounded_null_filled (_broadcast_info->origination_time, sizeof (_broadcast_info->origination_time), "%02d:%02d:%02d",
				      now.tm_hour,
				      now.tm_min,
				      now.tm_sec);
	
	/* now update header position taking header offset into account */
	
	set_header_timeline_position ();

	if (sf_command (sf, SFC_SET_BROADCAST_INFO, _broadcast_info, sizeof (*_broadcast_info)) != SF_TRUE) {
		error << string_compose (_("cannot set broadcast info for audio file %1; Dropping broadcast info for this file"), _path) << endmsg;
		_flags = Flag (_flags & ~Broadcast);
		delete _broadcast_info;
		_broadcast_info = 0;
		return -1;
	}

	return 0;
}

void
SndFileSource::set_header_timeline_position ()
{
	if (!(_flags & Broadcast)) {
		return;
	}

       _broadcast_info->time_reference_high = (timeline_position >> 32);
       _broadcast_info->time_reference_low = (timeline_position & 0xffffffff);

	if (sf_command (sf, SFC_SET_BROADCAST_INFO, _broadcast_info, sizeof (*_broadcast_info)) != SF_TRUE) {
		error << string_compose (_("cannot set broadcast info for audio file %1; Dropping broadcast info for this file"), _path) << endmsg;
		_flags = Flag (_flags & ~Broadcast);
		delete _broadcast_info;
		_broadcast_info = 0;
	}
}

nframes_t
SndFileSource::write_float (Sample* data, nframes_t frame_pos, nframes_t cnt)
{
	if (sf_seek (sf, frame_pos, SEEK_SET|SFM_WRITE) < 0) {
		char errbuf[256];
		sf_error_str (0, errbuf, sizeof (errbuf) - 1);
		error << string_compose (_("%1: cannot seek to %2 (libsndfile error: %3"), _path, frame_pos, errbuf) << endmsg;
		return 0;
	}
	
	if (sf_writef_float (sf, data, cnt) != (ssize_t) cnt) {
		return 0;
	}
	
	return cnt;
}

nframes_t
SndFileSource::natural_position() const
{
	return timeline_position;
}

bool
SndFileSource::set_destructive (bool yn)
{
	if (yn) {
		_flags = Flag (_flags | Destructive);
		if (!xfade_buf) {
			xfade_buf = new Sample[xfade_frames];
		}
		clear_capture_marks ();
		timeline_position = header_position_offset;
	} else {
		_flags = Flag (_flags & ~Destructive);
		timeline_position = 0;
		/* leave xfade buf alone in case we need it again later */
	}

	return true;
}

void
SndFileSource::clear_capture_marks ()
{
	_capture_start = false;
	_capture_end = false;
}	

void
SndFileSource::mark_capture_start (nframes_t pos)
{
	if (destructive()) {
		if (pos < timeline_position) {
			_capture_start = false;
		} else {
			_capture_start = true;
			capture_start_frame = pos;
		}
	}
}

void
SndFileSource::mark_capture_end()
{
	if (destructive()) {
		_capture_end = true;
	}
}

nframes_t
SndFileSource::crossfade (Sample* data, nframes_t cnt, int fade_in)
{
	nframes_t xfade = min (xfade_frames, cnt);
	nframes_t nofade = cnt - xfade;
	Sample* fade_data = 0;
	nframes_t fade_position = 0; // in frames
	ssize_t retval;
	nframes_t file_cnt;

	if (fade_in) {
		fade_position = file_pos;
		fade_data = data;
	} else {
		fade_position = file_pos + nofade;
		fade_data = data + nofade;
	}

	if (fade_position > _length) {
		
		/* read starts beyond end of data, just memset to zero */
		
		file_cnt = 0;

	} else if (fade_position + xfade > _length) {
		
		/* read ends beyond end of data, read some, memset the rest */
		
		file_cnt = _length - fade_position;

	} else {
		
		/* read is entirely within data */

		file_cnt = xfade;
	}

	if (file_cnt) {
		
		if ((retval = read_unlocked (xfade_buf, fade_position, file_cnt)) != (ssize_t) file_cnt) {
			if (retval >= 0 && errno == EAGAIN) {
				/* XXX - can we really trust that errno is meaningful here?  yes POSIX, i'm talking to you.
				 * short or no data there */
				memset (xfade_buf, 0, xfade * sizeof(Sample));
			} else {
				error << string_compose(_("SndFileSource: \"%1\" bad read retval: %2 of %5 (%3: %4)"), _path, retval, errno, strerror (errno), xfade) << endmsg;
				return 0;
			}
		}
	} 

	if (file_cnt != xfade) {
		nframes_t delta = xfade - file_cnt;
		memset (xfade_buf+file_cnt, 0, sizeof (Sample) * delta);
	}
	
	if (nofade && !fade_in) {
		if (write_float (data, file_pos, nofade) != nofade) {
			error << string_compose(_("SndFileSource: \"%1\" bad write (%2)"), _path, strerror (errno)) << endmsg;
			return 0;
		}
	}

	if (xfade == xfade_frames) {

		nframes_t n;

		/* use the standard xfade curve */
		
		if (fade_in) {

			/* fade new material in */
			
			for (n = 0; n < xfade; ++n) {
				xfade_buf[n] = (xfade_buf[n] * out_coefficient[n]) + (fade_data[n] * in_coefficient[n]);
			}

		} else {


			/* fade new material out */
			
			for (n = 0; n < xfade; ++n) {
				xfade_buf[n] = (xfade_buf[n] * in_coefficient[n]) + (fade_data[n] * out_coefficient[n]);
			}
		}

	} else if (xfade < xfade_frames) {

		gain_t in[xfade];
		gain_t out[xfade];

		/* short xfade, compute custom curve */

		compute_equal_power_fades (xfade, in, out);

		for (nframes_t n = 0; n < xfade; ++n) {
			xfade_buf[n] = (xfade_buf[n] * out[n]) + (fade_data[n] * in[n]);		
		}

	} else if (xfade) {

		/* long xfade length, has to be computed across several calls */

	}

	if (xfade) {
		if (write_float (xfade_buf, fade_position, xfade) != xfade) {
			error << string_compose(_("SndFileSource: \"%1\" bad write (%2)"), _path, strerror (errno)) << endmsg;
			return 0;
		}
	}
	
	if (fade_in && nofade) {
		if (write_float (data + xfade, file_pos + xfade, nofade) != nofade) {
			error << string_compose(_("SndFileSource: \"%1\" bad write (%2)"), _path, strerror (errno)) << endmsg;
			return 0;
		}
	}

	return cnt;
}

nframes_t
SndFileSource::last_capture_start_frame () const
{
	if (destructive()) {
		return capture_start_frame;
	} else {
		return 0;
	}
}

void
SndFileSource::handle_header_position_change ()
{
	if (destructive()) {
		if ( _length != 0 ) {
			error << string_compose(_("Filesource: start time is already set for existing file (%1): Cannot change start time."), _path ) << endmsg;
			//in the future, pop up a dialog here that allows user to regenerate file with new start offset
		} else if (writable()) {
			timeline_position = header_position_offset;
			set_header_timeline_position ();  //this will get flushed if/when the file is recorded to
		}
	}
}

void
SndFileSource::setup_standard_crossfades (nframes_t rate)
{
	/* This static method is assumed to have been called by the Session
	   before any DFS's are created.
	*/

	xfade_frames = (nframes_t) floor ((Config->get_destructive_xfade_msecs () / 1000.0) * rate);

	if (out_coefficient) {
		delete [] out_coefficient;
	}

	if (in_coefficient) {
		delete [] in_coefficient;
	}

	out_coefficient = new gain_t[xfade_frames];
	in_coefficient = new gain_t[xfade_frames];

	compute_equal_power_fades (xfade_frames, in_coefficient, out_coefficient);
}

void
SndFileSource::set_timeline_position (int64_t pos)
{
	// destructive track timeline postion does not change
	// except at instantion or when header_position_offset 
	// (session start) changes

	if (!destructive()) {
		AudioFileSource::set_timeline_position (pos);
	} 
}

int
SndFileSource::get_soundfile_info (const ustring& path, SoundFileInfo& info, string& error_msg)
{
	SNDFILE *sf;
	SF_INFO sf_info;
	SF_BROADCAST_INFO binfo;
	bool timecode_exists;

	sf_info.format = 0; // libsndfile says to clear this before sf_open().

	if ((sf = sf_open ((char*) path.c_str(), SFM_READ, &sf_info)) == 0) { 
		char errbuf[256];
		error_msg = sf_error_str (0, errbuf, sizeof (errbuf) - 1);
		return false;
	}

	info.samplerate  = sf_info.samplerate;
	info.channels    = sf_info.channels;
	info.length      = sf_info.frames;
	info.format_name = string_compose("%1\n%2",
					   sndfile_major_format(sf_info.format),
					   sndfile_minor_format(sf_info.format));

	memset (&binfo, 0, sizeof (binfo));
	info.timecode  = get_timecode_info (sf, &binfo, timecode_exists);

	if (!timecode_exists) {
		info.timecode = 0;
	}
	
	sf_close (sf);

	return true;
}

int64_t
SndFileSource::get_timecode_info (SNDFILE* sf, SF_BROADCAST_INFO* binfo, bool& exists)
{
	if (sf_command (sf, SFC_GET_BROADCAST_INFO, binfo, sizeof (*binfo)) != SF_TRUE) {
		exists = false;
		return (header_position_offset);
	} 
	
	/* XXX 64 bit alert: when JACK switches to a 64 bit frame count, this needs to use the high bits
	   of the time reference.
	*/
	
	exists = true;
	int64_t ret = (uint32_t) binfo->time_reference_high;
	ret <<= 32;
	ret |= (uint32_t) binfo->time_reference_low;
	return ret;
}

bool
SndFileSource::one_of_several_channels () const
{
	return _info.channels > 1;
}

