rollback to 3428, before the mysterious removal of libs/* at 3431/3432

git-svn-id: svn://localhost/ardour2/branches/3.0@3435 d708f5d6-7413-0410-9779-e7cbd77b26cf

1 files changed, 932 insertions, 0 deletions

diff --git a/libs/ardour/audiosource.cc b/libs/ardour/audiosource.cc
new file mode 100644
index 0000000000..01dea08d3e
--- /dev/null
+++ b/libs/ardour/audiosource.cc
@@ -0,0 +1,932 @@
+/*
+    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.
+
+*/
+
+#include <sys/stat.h>
+#include <unistd.h>
+#include <fcntl.h>
+#include <poll.h>
+#include <float.h>
+#include <utime.h>
+#include <cerrno>
+#include <ctime>
+#include <cmath>
+#include <iomanip>
+#include <fstream>
+#include <algorithm>
+#include <vector>
+
+#include <glibmm/fileutils.h>
+#include <glibmm/miscutils.h>
+
+#include <pbd/xml++.h>
+#include <pbd/pthread_utils.h>
+
+#include <ardour/audiosource.h>
+#include <ardour/cycle_timer.h>
+#include <ardour/session.h>
+#include <ardour/transient_detector.h>
+
+#include "i18n.h"
+
+using namespace std;
+using namespace ARDOUR;
+using namespace PBD;
+using Glib::ustring;
+
+bool AudioSource::_build_missing_peakfiles = false;
+bool AudioSource::_build_peakfiles = false;
+
+#define _FPP 256
+
+AudioSource::AudioSource (Session& s, ustring name)
+	: Source (s, name, DataType::AUDIO)
+{
+	_peaks_built = false;
+	_peak_byte_max = 0;
+	peakfile = -1;
+	_read_data_count = 0;
+	_write_data_count = 0;
+	peak_leftover_cnt = 0;
+	peak_leftover_size = 0;
+	peak_leftovers = 0;
+}
+
+AudioSource::AudioSource (Session& s, const XMLNode& node) 
+	: Source (s, node)
+{
+	
+	_peaks_built = false;
+	_peak_byte_max = 0;
+	peakfile = -1;
+	_read_data_count = 0;
+	_write_data_count = 0;
+	peak_leftover_cnt = 0;
+	peak_leftover_size = 0;
+	peak_leftovers = 0;
+
+	if (set_state (node)) {
+		throw failed_constructor();
+	}
+}
+
+AudioSource::~AudioSource ()
+{
+	/* shouldn't happen but make sure we don't leak file descriptors anyway */
+	
+	if (peak_leftover_cnt) {
+		cerr << "AudioSource destroyed with leftover peak data pending" << endl;
+	}
+
+	if (peakfile >= 0) {
+		::close (peakfile);
+	}
+
+	if (peak_leftovers) {
+		delete [] peak_leftovers;
+	}
+}
+
+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
+ ***********************************************************************/
+
+bool
+AudioSource::peaks_ready (sigc::slot<void> the_slot, sigc::connection& conn) const
+{
+	bool ret;
+	Glib::Mutex::Lock lm (_peaks_ready_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;
+}
+
+void
+AudioSource::touch_peakfile ()
+{
+	struct stat statbuf;
+
+	if (stat (peakpath.c_str(), &statbuf) != 0 || statbuf.st_size == 0) {
+		return;
+	}
+	
+	struct utimbuf tbuf;
+	
+	tbuf.actime = statbuf.st_atime;
+	tbuf.modtime = time ((time_t) 0);
+	
+	utime (peakpath.c_str(), &tbuf);
+}
+
+int
+AudioSource::rename_peakfile (ustring newpath)
+{
+	/* caller must hold _lock */
+
+	ustring 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, ustring audio_path)
+{
+	struct stat statbuf;
+
+	peakpath = peak_path (audio_path);
+
+	/* if the peak file should be there, but isn't .... */
+	
+	if (!newfile && !Glib::file_test (peakpath.c_str(), Glib::FILE_TEST_EXISTS)) {
+		peakpath = find_broken_peakfile (peakpath, audio_path);
+	}
+
+	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;
+		}
+
+		/* peakfile does not exist */
+		
+		_peaks_built = false;
+		
+	} else {
+		
+		/* we found it in the peaks dir, so check it out */
+		
+		if (statbuf.st_size == 0 || (statbuf.st_size < ((length() / _FPP) * sizeof (PeakData)))) {
+			// empty
+			_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) {
+				_peaks_built = false;
+				_peak_byte_max = 0;
+			} else {
+
+				/* allow 6 seconds slop on checking peak vs. file times because of various
+				   disk action "races"
+				*/
+
+				if (stat_file.st_mtime > statbuf.st_mtime && (stat_file.st_mtime - statbuf.st_mtime > 6)) {
+					_peaks_built = false;
+					_peak_byte_max = 0;
+				} else {
+					_peaks_built = true;
+					_peak_byte_max = statbuf.st_size;
+				}
+			}
+		}
+	}
+
+	if (!newfile && !_peaks_built && _build_missing_peakfiles && _build_peakfiles) {
+		build_peaks_from_scratch ();
+	} 
+	
+	return 0;
+}
+
+nframes_t
+AudioSource::read (Sample *dst, nframes_t start, nframes_t cnt) const
+{
+	Glib::Mutex::Lock lm (_lock);
+	return read_unlocked (dst, start, cnt);
+}
+
+nframes_t
+AudioSource::write (Sample *dst, nframes_t cnt)
+{
+	Glib::Mutex::Lock lm (_lock);
+	return write_unlocked (dst, cnt);
+}
+
+int
+AudioSource::read_peaks (PeakData *peaks, nframes_t npeaks, nframes_t start, nframes_t cnt, double samples_per_visual_peak) const
+{
+	return read_peaks_with_fpp (peaks, npeaks, start, cnt, samples_per_visual_peak, _FPP);
+}
+
+int 
+AudioSource::read_peaks_with_fpp (PeakData *peaks, nframes_t npeaks, nframes_t start, nframes_t cnt, 
+				  double samples_per_visual_peak, nframes_t samples_per_file_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;
+	nframes_t zero_fill = 0;
+	int ret = -1;
+	PeakData* staging = 0;
+	Sample* raw_staging = 0;
+	int _peakfile = -1;
+
+	expected_peaks = (cnt / (double) samples_per_file_peak);
+	scale = npeaks/expected_peaks;
+
+#undef DEBUG_READ_PEAKS
+#ifdef DEBUG_READ_PEAKS
+	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;
+		nframes_t old = npeaks;
+		npeaks = min ((nframes_t) floor (cnt / samples_per_visual_peak), npeaks);
+		zero_fill = old - npeaks;
+	}
+
+	// cerr << "actual npeaks = " << npeaks << " zf = " << zero_fill << endl;
+	
+	if (npeaks == cnt) {
+
+#ifdef DEBUG_READ_PEAKS
+		cerr << "RAW DATA\n";
+#endif		
+		/* 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 (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) {
+
+		off_t first_peak_byte = (start / samples_per_file_peak) * sizeof (PeakData);
+
+		/* open, read, close */
+
+		if ((_peakfile = ::open (peakpath.c_str(), O_RDONLY, 0664)) < 0) {
+			error << string_compose(_("AudioSource: cannot open peakpath (a) \"%1\" (%2)"), peakpath, strerror (errno)) << endmsg;
+			return -1;
+		}
+
+#ifdef DEBUG_READ_PEAKS
+		cerr << "DIRECT PEAKS\n";
+#endif
+		
+		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;
+	}
+
+
+	nframes_t tnp;
+
+	if (scale < 1.0) {
+
+#ifdef DEBUG_READ_PEAKS
+		cerr << "DOWNSAMPLE\n";
+#endif		
+		/* 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, 65536.0);
+		
+		staging = new PeakData[chunksize];
+		
+		/* compute the rounded up frame position  */
+	
+		nframes_t current_frame = start;
+		nframes_t current_stored_peak = (nframes_t) ceil (current_frame / (double) samples_per_file_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 = (nframes_t) next_visual_peak_frame / samples_per_file_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_RDONLY, 0664)) < 0) {
+			error << string_compose(_("AudioSource: cannot open peakpath (b) \"%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/samples_per_file_peak - current_stored_peak), (nframes_t) expected_peaks);
+				to_read = min (chunksize, tnp);
+				
+#ifdef DEBUG_READ_PEAKS
+				cerr << "read " << sizeof (PeakData) * to_read << " from peakfile @ " << start_byte << endl;
+#endif
+				
+				if ((nread = ::pread (_peakfile, staging, sizeof (PeakData) * to_read, start_byte))
+				    != sizeof (PeakData) * to_read) {
+
+					off_t fend = lseek (_peakfile, 0, SEEK_END);
+					
+					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)/samples_per_file_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 / samples_per_file_peak; 
+		}
+
+		if (zero_fill) {
+ 			memset (&peaks[npeaks], 0, sizeof (PeakData) * zero_fill);
+ 		}
+		
+		ret = 0;
+
+	} else {
+		
+#ifdef DEBUG_READ_PEAKS
+		cerr << "UPSAMPLE\n";
+#endif
+		/* 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.
+		*/
+
+		nframes_t frames_read = 0;
+		nframes_t current_frame = start;
+		nframes_t i = 0;
+		nframes_t nvisual_peaks = 0;
+		nframes_t chunksize = (nframes_t) min (cnt, (nframes_t) 4096);
+		raw_staging = new Sample[chunksize];
+		
+		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 (to_read == 0) {
+					/* XXX ARGH .. out by one error ... need to figure out why this happens
+					   and fix it rather than do this band-aid move.
+					*/
+					zero_fill = npeaks - nvisual_peaks;
+					break;
+				}
+
+				if ((frames_read = read_unlocked (raw_staging, current_frame, to_read)) == 0) {
+					error << string_compose(_("AudioSource[%1]: peak read - cannot read %2 samples at offset %3 of %4 (%5)"),
+								_name, to_read, current_frame, _length, strerror (errno)) 
+					      << 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;
+	}
+
+#ifdef DEBUG_READ_PEAKS
+	cerr << "RP DONE\n";
+#endif
+
+	return ret;
+}
+
+#undef DEBUG_PEAK_BUILD
+
+int
+AudioSource::build_peaks_from_scratch ()
+{
+	nframes_t current_frame;
+	nframes_t cnt;
+	Sample* buf = 0;
+	nframes_t frames_read;
+	nframes_t frames_to_read;
+	const nframes_t bufsize = 65536; // 256kB per disk read for mono data is about ideal
+
+	int ret = -1;
+
+	{
+		/* hold lock while building peaks */
+
+		Glib::Mutex::Lock lp (_lock);
+		
+		if (prepare_for_peakfile_writes ()) {
+			goto out;
+		}
+		
+		current_frame = 0;
+		cnt = _length;
+		_peaks_built = false;
+		buf = new Sample[bufsize];
+		
+		while (cnt) {
+			
+			frames_to_read = min (bufsize, cnt);
+
+			if ((frames_read = read_unlocked (buf, current_frame, frames_to_read)) != frames_to_read) {
+				error << string_compose(_("%1: could not write read raw data for peak computation (%2)"), _name, strerror (errno)) << endmsg;
+				done_with_peakfile_writes (false);
+				goto out;
+			}
+
+			if (compute_and_write_peaks (buf, current_frame, frames_read, true, false, _FPP)) {
+				break;
+			}
+			
+			current_frame += frames_read;
+			cnt -= frames_read;
+		}
+
+		if (cnt == 0) {
+			/* success */
+			truncate_peakfile();
+		} 
+
+		done_with_peakfile_writes ((cnt == 0));
+	}
+	
+	{
+		Glib::Mutex::Lock lm (_peaks_ready_lock);
+		
+		if (_peaks_built) {
+			PeaksReady (); /* EMIT SIGNAL */
+			ret = 0;
+		}
+	}
+
+  out:
+	if (ret) {
+		unlink (peakpath.c_str());
+	}
+
+	if (buf) {
+		delete [] buf;
+	}
+
+	return ret;
+}
+
+int
+AudioSource::prepare_for_peakfile_writes ()
+{
+	if ((peakfile = ::open (peakpath.c_str(), O_RDWR|O_CREAT, 0664)) < 0) {
+		error << string_compose(_("AudioSource: cannot open peakpath (c) \"%1\" (%2)"), peakpath, strerror (errno)) << endmsg;
+		return -1;
+	}
+	return 0;
+}
+
+void
+AudioSource::done_with_peakfile_writes (bool done)
+{
+	if (peak_leftover_cnt) {
+		compute_and_write_peaks (0, 0, 0, true, false, _FPP);
+	}
+	
+	if (done) {
+		_peaks_built = true;
+	}
+
+	if (peakfile >= 0) {
+		close (peakfile);
+		peakfile = -1;
+	}
+}
+
+int
+AudioSource::compute_and_write_peaks (Sample* buf, nframes_t first_frame, nframes_t cnt, bool force, bool intermediate_peaks_ready)
+{
+	return compute_and_write_peaks (buf, first_frame, cnt, force, intermediate_peaks_ready, _FPP);
+}
+
+int
+AudioSource::compute_and_write_peaks (Sample* buf, nframes_t first_frame, nframes_t cnt, bool force, 
+				      bool intermediate_peaks_ready, nframes_t fpp)
+{
+	Sample* buf2 = 0;
+	nframes_t to_do;
+	uint32_t  peaks_computed;
+	PeakData* peakbuf = 0;
+	int ret = -1;
+	nframes_t current_frame;
+	nframes_t frames_done;
+	const size_t blocksize = (128 * 1024);
+	off_t first_peak_byte;
+
+	if (peakfile < 0) {
+		prepare_for_peakfile_writes ();
+	}
+
+  restart:
+	if (peak_leftover_cnt) {
+
+		if (first_frame != peak_leftover_frame + peak_leftover_cnt) {
+
+			/* uh-oh, ::seek() since the last ::compute_and_write_peaks(), 
+			   and we have leftovers. flush a single peak (since the leftovers
+			   never represent more than that, and restart.
+			*/
+			
+			PeakData x;
+			
+			x.min = peak_leftovers[0];
+			x.max = peak_leftovers[0];
+
+			off_t byte = (peak_leftover_frame / fpp) * sizeof (PeakData);
+
+			if (::pwrite (peakfile, &x, sizeof (PeakData), byte) != sizeof (PeakData)) {
+				error << string_compose(_("%1: could not write peak file data (%2)"), _name, strerror (errno)) << endmsg;
+				goto out;
+			}
+
+			_peak_byte_max = max (_peak_byte_max, (off_t) (byte + sizeof(PeakData)));
+
+			{ 
+				Glib::Mutex::Lock lm (_peaks_ready_lock);
+				PeakRangeReady (peak_leftover_frame, peak_leftover_cnt); /* EMIT SIGNAL */
+				if (intermediate_peaks_ready) {
+					PeaksReady (); /* EMIT SIGNAL */
+				} 
+			}
+
+			/* left overs are done */
+
+			peak_leftover_cnt = 0;
+			goto restart;
+		}
+
+		/* else ... had leftovers, but they immediately preceed the new data, so just
+		   merge them and compute.
+		*/
+
+		/* make a new contiguous buffer containing leftovers and the new stuff */
+
+		to_do = cnt + peak_leftover_cnt;
+		buf2 = new Sample[to_do];
+
+		/* the remnants */
+		memcpy (buf2, peak_leftovers, peak_leftover_cnt * sizeof (Sample));
+
+		/* the new stuff */
+		memcpy (buf2+peak_leftover_cnt, buf, cnt * sizeof (Sample));
+
+		/* no more leftovers */
+		peak_leftover_cnt = 0;
+
+		/* use the temporary buffer */
+		buf = buf2;
+
+		/* make sure that when we write into the peakfile, we startup where we left off */
+
+		first_frame = peak_leftover_frame;
+		
+	} else {
+		to_do = cnt;
+	}
+
+	peakbuf = new PeakData[(to_do/fpp)+1];
+	peaks_computed = 0;
+	current_frame = first_frame;
+	frames_done = 0;
+
+	while (to_do) {
+
+		/* if some frames were passed in (i.e. we're not flushing leftovers)
+		   and there are less than fpp to do, save them till
+		   next time
+		*/
+
+		if (force && (to_do < fpp)) {
+			/* keep the left overs around for next time */
+
+			if (peak_leftover_size < to_do) {
+				delete [] peak_leftovers;
+				peak_leftovers = new Sample[to_do];
+				peak_leftover_size = to_do;
+			}
+			memcpy (peak_leftovers, buf, to_do * sizeof (Sample));
+			peak_leftover_cnt = to_do;
+			peak_leftover_frame = current_frame;
+
+			/* done for now */
+
+			break;
+		}
+			
+		nframes_t this_time = min (fpp, to_do);
+
+		peakbuf[peaks_computed].max = buf[0];
+		peakbuf[peaks_computed].min = buf[0];
+
+		ARDOUR::find_peaks (buf+1, this_time-1, &peakbuf[peaks_computed].min, &peakbuf[peaks_computed].max);
+
+		peaks_computed++;
+		buf += this_time;
+		to_do -= this_time;
+		frames_done += this_time;
+		current_frame += this_time;
+	}
+		
+	first_peak_byte = (first_frame / fpp) * sizeof (PeakData);
+
+	if (can_truncate_peaks()) {
+
+		/* on some filesystems (ext3, at least) this helps to reduce fragmentation of
+		   the peakfiles. its not guaranteed to do so, and even on ext3 (as of december 2006)
+		   it does not cause single-extent allocation even for peakfiles of 
+		   less than BLOCKSIZE bytes.  only call ftruncate if we'll make the file larger.
+		*/
+		
+		off_t endpos = lseek (peakfile, 0, SEEK_END);
+		off_t target_length = blocksize * ((first_peak_byte + blocksize + 1) / blocksize);
+		
+		if (endpos < target_length) {
+			ftruncate (peakfile, target_length);
+			/* error doesn't actually matter though, so continue on without testing */
+		}
+	}
+
+	if (::pwrite (peakfile, peakbuf, sizeof (PeakData) * peaks_computed, first_peak_byte) != (ssize_t) (sizeof (PeakData) * peaks_computed)) {
+		error << string_compose(_("%1: could not write peak file data (%2)"), _name, strerror (errno)) << endmsg;
+		goto out;
+	}
+
+	_peak_byte_max = max (_peak_byte_max, (off_t) (first_peak_byte + sizeof(PeakData)*peaks_computed));	
+
+	if (frames_done) {
+		Glib::Mutex::Lock lm (_peaks_ready_lock);
+		PeakRangeReady (first_frame, frames_done); /* EMIT SIGNAL */
+		if (intermediate_peaks_ready) {
+			PeaksReady (); /* EMIT SIGNAL */
+		}
+	}
+
+	ret = 0;
+
+  out:
+	delete [] peakbuf;
+	if (buf2) {
+		delete [] buf2;
+	}
+	return ret;
+}
+
+void
+AudioSource::truncate_peakfile ()
+{
+	if (peakfile < 0) {
+		error << string_compose (_("programming error: %1"), "AudioSource::truncate_peakfile() called without open peakfile descriptor")
+		      << endmsg;
+		return;
+	}
+
+	/* truncate the peakfile down to its natural length if necessary */
+
+	off_t end = lseek (peakfile, 0, SEEK_END);
+	
+	if (end > _peak_byte_max) {
+		ftruncate (peakfile, _peak_byte_max);
+	}
+}
+
+bool
+AudioSource::file_changed (ustring 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;
+	}
+}
+
+nframes_t
+AudioSource::available_peaks (double zoom_factor) const
+{
+	off_t end;
+
+	if (zoom_factor < _FPP) {
+		return length(); // peak data will come from the audio file
+	} 
+	
+	/* peak data comes from peakfile, but the filesize might not represent
+	   the valid data due to ftruncate optimizations, so use _peak_byte_max state.
+	   XXX - there might be some atomicity issues here, we should probably add a lock,
+	   but _peak_byte_max only monotonically increases after initialization.
+	*/
+
+	end = _peak_byte_max;
+
+	return (end/sizeof(PeakData)) * _FPP;
+}
+
+void
+AudioSource::update_length (nframes_t pos, nframes_t cnt)
+{
+	if (pos + cnt > _length) {
+		_length = pos+cnt;
+	}
+}
+