Merged with trunk revision 600

git-svn-id: svn://localhost/ardour2/branches/midi@601 d708f5d6-7413-0410-9779-e7cbd77b26cf

1 files changed, 897 insertions, 0 deletions

diff --git a/libs/ardour/audiosource.cc b/libs/ardour/audiosource.cc
new file mode 100644
index 0000000000..46596ad64f
--- /dev/null
+++ b/libs/ardour/audiosource.cc
@@ -0,0 +1,897 @@
+/*
+    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 404 2006-03-17 17:39:21Z pauld $
+*/
+
+#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/xml++.h>
+#include <pbd/pthread_utils.h>
+
+#include <ardour/audiosource.h>
+
+#include "i18n.h"
+
+using namespace std;
+using namespace ARDOUR;
+using namespace PBD;
+
+sigc::signal<void,AudioSource *> AudioSource::AudioSourceCreated;
+pthread_t                    AudioSource::peak_thread;
+bool                         AudioSource::have_peak_thread = false;
+vector<AudioSource*>         AudioSource::pending_peak_sources;
+Glib::Mutex*                 AudioSource::pending_peak_sources_lock = 0;
+int                          AudioSource::peak_request_pipe[2];
+
+bool AudioSource::_build_missing_peakfiles = false;
+bool AudioSource::_build_peakfiles = false;
+
+AudioSource::AudioSource (string name)
+	: Source (name)
+{
+	if (pending_peak_sources_lock == 0) {
+		pending_peak_sources_lock = new Glib::Mutex;
+	}
+
+	_peaks_built = false;
+	next_peak_clear_should_notify = true;
+	_read_data_count = 0;
+	_write_data_count = 0;
+}
+
+AudioSource::AudioSource (const XMLNode& node) 
+	: Source (node)
+{
+	if (pending_peak_sources_lock == 0) {
+		pending_peak_sources_lock = new Glib::Mutex;
+	}
+
+	_peaks_built = false;
+	next_peak_clear_should_notify = true;
+	_read_data_count = 0;
+	_write_data_count = 0;
+
+	if (set_state (node)) {
+		throw failed_constructor();
+	}
+}
+
+AudioSource::~AudioSource ()
+{
+}
+
+XMLNode&
+AudioSource::get_state ()
+{
+	XMLNode& node (Source::get_state());
+
+	if (_captured_for.length()) {
+		node.add_property ("captured-for", _captured_for);
+	}
+
+	return node;
+}
+
+int
+AudioSource::set_state (const XMLNode& node)
+{
+	const XMLProperty* prop;
+
+	Source::set_state (node);
+
+	if ((prop = node.property ("captured-for")) != 0) {
+		_captured_for = prop->value();
+	}
+
+	return 0;
+}
+
+/***********************************************************************
+  PEAK FILE STUFF
+ ***********************************************************************/
+
+void*
+AudioSource::peak_thread_work (void* arg)
+{
+	PBD::ThreadCreated (pthread_self(), X_("Peak"));
+	struct pollfd pfd[1];
+
+	if (pending_peak_sources_lock == 0) {
+		pending_peak_sources_lock = new Glib::Mutex;
+	}
+
+	Glib::Mutex::Lock lm (*pending_peak_sources_lock);
+
+	while (true) {
+
+		pfd[0].fd = peak_request_pipe[0];
+		pfd[0].events = POLLIN|POLLERR|POLLHUP;
+
+		pending_peak_sources_lock->unlock ();
+
+		if (poll (pfd, 1, -1) < 0) {
+
+			if (errno == EINTR) {
+				pending_peak_sources_lock->lock ();
+				continue;
+			}
+			
+			error << string_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*/
+				}
+			}
+		}
+
+		pending_peak_sources_lock->lock ();
+
+		while (!pending_peak_sources.empty()) {
+
+			AudioSource* s = pending_peak_sources.front();
+			pending_peak_sources.erase (pending_peak_sources.begin());
+			
+			pending_peak_sources_lock->unlock ();
+			s->build_peaks();
+			pending_peak_sources_lock->lock ();
+		}
+	}
+
+	pthread_exit_pbd (0);
+	/*NOTREACHED*/
+	return 0;
+}
+
+int
+AudioSource::start_peak_thread ()
+{
+	if (!_build_peakfiles) {
+		return 0;
+	}
+
+	if (pipe (peak_request_pipe)) {
+		error << string_compose(_("Cannot create transport request signal pipe (%1)"), strerror (errno)) << endmsg;
+		return -1;
+	}
+
+	if (fcntl (peak_request_pipe[0], F_SETFL, O_NONBLOCK)) {
+		error << string_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 << string_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 << _("AudioSource: could not create peak thread") << endmsg;
+		return -1;
+	}
+
+	have_peak_thread = true;
+	return 0;
+}
+
+void
+AudioSource::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 
+AudioSource::queue_for_peaks (AudioSource& source)
+{
+	if (have_peak_thread) {
+
+		Glib::Mutex::Lock lm (*pending_peak_sources_lock);
+		
+		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 AudioSource::clear_queue_for_peaks ()
+{
+	/* this is done to cancel a group of running peak builds */
+	if (have_peak_thread) {
+		Glib::Mutex::Lock lm (*pending_peak_sources_lock);
+		pending_peak_sources.clear ();
+	}
+}
+
+
+bool
+AudioSource::peaks_ready (sigc::slot<void> the_slot, sigc::connection& conn) const
+{
+	bool ret;
+	Glib::Mutex::Lock lm (_lock);
+
+	/* check to see if the peak data is ready. if not
+	   connect the slot while still holding the lock.
+	*/
+
+	if (!(ret = _peaks_built)) {
+		conn = PeaksReady.connect (the_slot);
+	}
+
+	return ret;
+}
+
+int
+AudioSource::rename_peakfile (string newpath)
+{
+	/* caller must hold _lock */
+
+	string oldpath = peakpath;
+
+	if (access (oldpath.c_str(), F_OK) == 0) {
+		if (rename (oldpath.c_str(), newpath.c_str()) != 0) {
+			error << string_compose (_("cannot rename peakfile for %1 from %2 to %3 (%4)"), _name, oldpath, newpath, strerror (errno)) << endmsg;
+			return -1;
+		}
+	}
+
+	peakpath = newpath;
+
+	return 0;
+}
+
+int
+AudioSource::initialize_peakfile (bool newfile, string audio_path)
+{
+	struct stat statbuf;
+
+	peakpath = peak_path (audio_path);
+
+	/* Nasty band-aid for older sessions that were created before we
+	   used libsndfile for all audio files.
+	*/
+	
+	if (!newfile && access (peakpath.c_str(), R_OK) != 0) {
+		string str = old_peak_path (audio_path);
+		if (access (str.c_str(), R_OK) == 0) {
+			peakpath = str;
+		}
+	}
+
+	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 << string_compose(_("AudioSource: cannot stat peakfile \"%1\""), peakpath) << endmsg;
+				return -1;
+			}
+
+		} 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 (!newfile && !_peaks_built && _build_missing_peakfiles && _build_peakfiles) {
+		build_peaks_from_scratch ();
+	} 
+
+	return 0;
+}
+
+jack_nframes_t
+AudioSource::read (Sample *dst, jack_nframes_t start, jack_nframes_t cnt, char * workbuf) const
+{
+	Glib::Mutex::Lock lm (_lock);
+	return read_unlocked (dst, start, cnt, workbuf);
+}
+
+jack_nframes_t
+AudioSource::write (Sample *dst, jack_nframes_t cnt, char * workbuf)
+{
+	Glib::Mutex::Lock lm (_lock);
+	return write_unlocked (dst, cnt, workbuf);
+}
+
+int 
+AudioSource::read_peaks (PeakData *peaks, jack_nframes_t npeaks, jack_nframes_t start, jack_nframes_t cnt, double samples_per_visual_peak) const
+{
+	Glib::Mutex::Lock lm (_lock);
+	double scale;
+	double expected_peaks;
+	PeakData::PeakDatum xmax;
+	PeakData::PeakDatum xmin;
+	int32_t to_read;
+	uint32_t nread;
+	jack_nframes_t zero_fill = 0;
+	int ret = -1;
+	PeakData* staging = 0;
+	Sample* raw_staging = 0;
+	char * workbuf = 0;
+	int peakfile = -1;
+
+	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];
+		workbuf = new char[cnt*4];
+		
+		if (read_unlocked (raw_staging, start, cnt, workbuf) != 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;
+		delete [] workbuf;
+		return 0;
+	}
+
+	if (scale == 1.0) {
+
+		off_t first_peak_byte = (start / frames_per_peak) * sizeof (PeakData);
+
+		/* open, read, close */
+
+		if ((peakfile = ::open (peakpath.c_str(), O_RDWR|O_CREAT, 0664)) < 0) {
+			error << string_compose(_("AudioSource: cannot open peakpath \"%1\" (%2)"), peakpath, strerror (errno)) << endmsg;
+			return -1;
+		}
+
+		// cerr << "DIRECT PEAKS\n";
+		
+		nread = ::pread (peakfile, peaks, sizeof (PeakData)* npeaks, first_peak_byte);
+		close (peakfile);
+
+		if (nread != sizeof (PeakData) * npeaks) {
+			cerr << "AudioSource["
+			     << _name
+			     << "]: cannot read peaks from peakfile! (read only " 
+			     << nread
+			     << " not " 
+			     << npeaks
+			      << "at sample " 
+			     << start
+			     << " = byte "
+			     << first_peak_byte
+			     << ')'
+			     << endl;
+			return -1;
+		}
+
+		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);
+
+		/* open ... close during out: handling */
+
+		if ((peakfile = ::open (peakpath.c_str(), O_RDWR|O_CREAT, 0664)) < 0) {
+			error << string_compose(_("AudioSource: cannot open peakpath \"%1\" (%2)"), peakpath, strerror (errno)) << endmsg;
+			return 0;
+		}
+
+		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);
+				
+				off_t fend = lseek (peakfile, 0, SEEK_END);
+				
+				if ((nread = ::pread (peakfile, staging, sizeof (PeakData) * to_read, start_byte))
+				    != sizeof (PeakData) * to_read) {
+					cerr << "AudioSource["
+					     << _name
+					     << "]: cannot read peak data from peakfile ("
+					     << (nread / sizeof(PeakData))
+					     << " peaks instead of "
+					     << to_read
+					     << ") ("
+					     << strerror (errno)
+					     << ')'
+					     << " at start_byte = " << start_byte 
+					     << " _length = " << _length << " versus len = " << fend
+					     << " expected maxpeaks = " << (_length - current_frame)/frames_per_peak
+					     << " npeaks was " << npeaks
+					     << endl;
+					goto out;
+				}
+
+				i = 0;
+				stored_peaks_read = nread / sizeof(PeakData);
+			}
+
+			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];
+		workbuf = new char[chunksize *4];
+		
+		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, workbuf)) < 0) {
+					error << string_compose(_("AudioSource[%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 (peakfile >= 0) {
+		close (peakfile);
+	}
+
+	if (staging) {
+		delete [] staging;
+	} 
+
+	if (raw_staging) {
+		delete [] raw_staging;
+	}
+
+	if (workbuf) {
+		delete [] workbuf;
+	}
+	
+	return ret;
+}
+
+#undef DEBUG_PEAK_BUILD
+
+int
+AudioSource::build_peaks ()
+{
+	vector<PeakBuildRecord*> built;
+	int status = -1;
+	bool pr_signal = false;
+	list<PeakBuildRecord*> copy;
+
+	{
+		Glib::Mutex::Lock lm (_lock);
+		copy = pending_peak_builds;
+		pending_peak_builds.clear ();
+	}
+		
+#ifdef DEBUG_PEAK_BUILD
+	cerr << "build peaks with " << copy.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;
+	}
+
+	{ 
+		Glib::Mutex::Lock lm (_lock);
+
+		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
+AudioSource::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;
+	char * workbuf = 0;
+	jack_nframes_t frames_read;
+	jack_nframes_t frames_to_read;
+	off_t first_peak_byte;
+	int peakfile = -1;
+	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;
+
+	workbuf = new char[max(frames_per_peak, cnt) * 4];
+	
+	if ((peakfile = ::open (peakpath.c_str(), O_RDWR|O_CREAT, 0664)) < 0) {
+		error << string_compose(_("AudioSource: cannot open peakpath \"%1\" (%2)"), peakpath, strerror (errno)) << endmsg;
+		return -1;
+	}
+	
+	while (cnt) {
+
+		frames_to_read = min (frames_per_peak, cnt);
+
+		if ((frames_read = read_unlocked (buf, current_frame, frames_to_read, workbuf)) != frames_to_read) {
+			error << string_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 << string_compose(_("%1: could not write peak file data (%2)"), _name, strerror (errno)) << endmsg;
+		goto out;
+	}
+
+	ret = 0;
+
+  out:
+	delete [] peakbuf;
+	if (peakfile >= 0) {
+		close (peakfile);
+	}
+	if (workbuf)
+		delete [] workbuf;
+	return ret;
+}
+
+void
+AudioSource::build_peaks_from_scratch ()
+{
+	Glib::Mutex::Lock lp (_lock);
+
+	next_peak_clear_should_notify = true;
+	pending_peak_builds.push_back (new PeakBuildRecord (0, _length));
+	queue_for_peaks (*this);
+}
+
+bool
+AudioSource::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;
+	}
+}
+
+jack_nframes_t
+AudioSource::available_peaks (double zoom_factor) const
+{
+	int peakfile;
+	off_t end;
+
+	if (zoom_factor < frames_per_peak) {
+		return length(); // peak data will come from the audio file
+	} 
+	
+	/* peak data comes from peakfile */
+
+	if ((peakfile = ::open (peakpath.c_str(), O_RDONLY)) < 0) {
+		error << string_compose(_("AudioSource: cannot open peakpath \"%1\" (%2)"), peakpath, strerror (errno)) << endmsg;
+		return 0;
+	}
+
+	{ 
+		Glib::Mutex::Lock lm (_lock);
+		end = lseek (peakfile, 0, SEEK_END);
+	}
+
+	close (peakfile);
+
+	return (end/sizeof(PeakData)) * frames_per_peak;
+}
+
+void
+AudioSource::update_length (jack_nframes_t pos, jack_nframes_t cnt)
+{
+	if (pos + cnt > _length) {
+		_length = pos+cnt;
+	}
+}
+