- LockMonitor lm (_lock, __LINE__, __FILE__);
- 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;
-
- 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);
-
- if ((nread = ::pread (peakfile, peaks, sizeof (PeakData)* npeaks, first_peak_byte)) != sizeof (PeakData) * npeaks) {
- cerr << "Source["
- << _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);
-
- 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);
-
- if ((nread = ::pread (peakfile, staging, sizeof (PeakData) * to_read, start_byte))
- != sizeof (PeakData) * to_read) {
- cerr << "Source["
- << _name
- << "]: cannot read peak data from peakfile ("
- << nread
- << " peaks instead of "
- << to_read
- << ") ("
- << strerror (errno)
- << ')'
- << " at start_byte = " << start_byte
- << " _length = " << _length
- << " 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;