libs/ardour/source.cc

   1 /*
   2     Copyright (C) 2000 Paul Davis
   3
   4     This program is free software; you can redistribute it and/or modify
   5     it under the terms of the GNU General Public License as published by
   6     the Free Software Foundation; either version 2 of the License, or
   7     (at your option) any later version.
   8
   9     This program is distributed in the hope that it will be useful,
  10     but WITHOUT ANY WARRANTY; without even the implied warranty of
  11     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12     GNU General Public License for more details.
  13
  14     You should have received a copy of the GNU General Public License
  15     along with this program; if not, write to the Free Software
  16     Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  17
  18     $Id$
  19 */
  20
  21 #include <sys/stat.h>
  22 #include <unistd.h>
  23 #include <fcntl.h>
  24 #include <poll.h>
  25 #include <float.h>
  26 #include <cerrno>
  27 #include <ctime>
  28 #include <cmath>
  29 #include <iomanip>
  30 #include <algorithm>
  31
  32 #include <pbd/lockmonitor.h>
  33 #include <pbd/xml++.h>
  34 #include <pbd/pthread_utils.h>
  35
  36 #include <ardour/source.h>
  37 #include <ardour/filesource.h>
  38 #include <ardour/sndfilesource.h>
  39
  40 #include "i18n.h"
  41
  42 using std::min;
  43 using std::max;
  44
  45 using namespace ARDOUR;
  46 using namespace PBD;
  47
  48 sigc::signal<void,Source *> Source::SourceCreated;
  49 pthread_t                    Source::peak_thread;
  50 bool                         Source::have_peak_thread = false;
  51 vector<Source*>              Source::pending_peak_sources;
  52 PBD::Lock                    Source::pending_peak_sources_lock;
  53 int                          Source::peak_request_pipe[2];
  54
  55 bool Source::_build_missing_peakfiles = false;
  56 bool Source::_build_peakfiles = false;
  57
  58 Source::Source (bool announce)
  59 {
  60         _id = ARDOUR::new_id();
  61         _use_cnt = 0;
  62         _peaks_built = false;
  63         next_peak_clear_should_notify = true;
  64         peakfile = -1;
  65         _timestamp = 0;
  66         _read_data_count = 0;
  67         _write_data_count = 0;
  68 }
  69
  70 Source::Source (const XMLNode& node)
  71 {
  72         _use_cnt = 0;
  73         _peaks_built = false;
  74         next_peak_clear_should_notify = true;
  75         peakfile = -1;
  76         _timestamp = 0;
  77         _read_data_count = 0;
  78         _write_data_count = 0;
  79
  80         if (set_state (node)) {
  81                 throw failed_constructor();
  82         }
  83 }
  84
  85 Source::~Source ()
  86 {
  87         if (peakfile >= 0) {
  88                 close (peakfile);
  89         }
  90 }
  91
  92 XMLNode&
  93 Source::get_state ()
  94 {
  95         XMLNode *node = new XMLNode ("Source");
  96         char buf[64];
  97
  98         node->add_property ("name", _name);
  99         snprintf (buf, sizeof(buf)-1, "%" PRIu64, _id);
 100         node->add_property ("id", buf);
 101
 102         if (_timestamp != 0) {
 103                 snprintf (buf, sizeof (buf), "%ld", _timestamp);
 104                 node->add_property ("timestamp", buf);
 105         }
 106
 107         if (_captured_for.length()) {
 108                 node->add_property ("captured-for", _captured_for);
 109         }
 110
 111         return *node;
 112 }
 113
 114 int
 115 Source::set_state (const XMLNode& node)
 116 {
 117         const XMLProperty* prop;
 118
 119         if ((prop = node.property ("name")) != 0) {
 120                 _name = prop->value();
 121         } else {
 122                 return -1;
 123         }
 124
 125         if ((prop = node.property ("id")) != 0) {
 126                 sscanf (prop->value().c_str(), "%" PRIu64, &_id);
 127         } else {
 128                 return -1;
 129         }
 130
 131         if ((prop = node.property ("timestamp")) != 0) {
 132                 sscanf (prop->value().c_str(), "%ld", &_timestamp);
 133         }
 134
 135         if ((prop = node.property ("captured-for")) != 0) {
 136                 _captured_for = prop->value();
 137         }
 138
 139         return 0;
 140 }
 141
 142 /***********************************************************************
 143   PEAK FILE STUFF
 144  ***********************************************************************/
 145
 146 void*
 147 Source::peak_thread_work (void* arg)
 148 {
 149         PBD::ThreadCreated (pthread_self(), X_("Peak"));
 150         struct pollfd pfd[1];
 151
 152         LockMonitor lm (pending_peak_sources_lock, __LINE__, __FILE__);
 153
 154         while (true) {
 155
 156                 pfd[0].fd = peak_request_pipe[0];
 157                 pfd[0].events = POLLIN|POLLERR|POLLHUP;
 158
 159                 pthread_mutex_unlock (pending_peak_sources_lock.mutex());
 160
 161                 if (poll (pfd, 1, -1) < 0) {
 162
 163                         if (errno == EINTR) {
 164                                 pthread_mutex_lock (pending_peak_sources_lock.mutex());
 165                                 continue;
 166                         }
 167
 168                         error << string_compose (_("poll on peak request pipe failed (%1)"),
 169                                           strerror (errno))
 170                               << endmsg;
 171                         break;
 172                 }
 173
 174                 if (pfd[0].revents & ~POLLIN) {
 175                         error << _("Error on peak thread request pipe") << endmsg;
 176                         break;
 177                 }
 178
 179                 if (pfd[0].revents & POLLIN) {
 180
 181                         char req;
 182
 183                         /* empty the pipe of all current requests */
 184
 185                         while (1) {
 186                                 size_t nread = ::read (peak_request_pipe[0], &req, sizeof (req));
 187
 188                                 if (nread == 1) {
 189                                         switch ((PeakRequest::Type) req) {
 190
 191                                         case PeakRequest::Build:
 192                                                 break;
 193
 194                                         case PeakRequest::Quit:
 195                                                 pthread_exit_pbd (0);
 196                                                 /*NOTREACHED*/
 197                                                 break;
 198
 199                                         default:
 200                                                 break;
 201                                         }
 202
 203                                 } else if (nread == 0) {
 204                                         break;
 205                                 } else if (errno == EAGAIN) {
 206                                         break;
 207                                 } else {
 208                                         fatal << _("Error reading from peak request pipe") << endmsg;
 209                                         /*NOTREACHED*/
 210                                 }
 211                         }
 212                 }
 213
 214                 pthread_mutex_lock (pending_peak_sources_lock.mutex());
 215
 216                 while (!pending_peak_sources.empty()) {
 217
 218                         Source* s = pending_peak_sources.front();
 219                         pending_peak_sources.erase (pending_peak_sources.begin());
 220
 221                         pthread_mutex_unlock (pending_peak_sources_lock.mutex());
 222                         s->build_peaks();
 223                         pthread_mutex_lock (pending_peak_sources_lock.mutex());
 224                 }
 225         }
 226
 227         pthread_exit_pbd (0);
 228         /*NOTREACHED*/
 229         return 0;
 230 }
 231
 232 int
 233 Source::start_peak_thread ()
 234 {
 235         if (!_build_peakfiles) {
 236                 return 0;
 237         }
 238
 239         if (pipe (peak_request_pipe)) {
 240                 error << string_compose(_("Cannot create transport request signal pipe (%1)"), strerror (errno)) << endmsg;
 241                 return -1;
 242         }
 243
 244         if (fcntl (peak_request_pipe[0], F_SETFL, O_NONBLOCK)) {
 245                 error << string_compose(_("UI: cannot set O_NONBLOCK on peak request pipe (%1)"), strerror (errno)) << endmsg;
 246                 return -1;
 247         }
 248
 249         if (fcntl (peak_request_pipe[1], F_SETFL, O_NONBLOCK)) {
 250                 error << string_compose(_("UI: cannot set O_NONBLOCK on peak request pipe (%1)"), strerror (errno)) << endmsg;
 251                 return -1;
 252         }
 253
 254         if (pthread_create_and_store ("peak file builder", &peak_thread, 0, peak_thread_work, 0)) {
 255                 error << _("Source: could not create peak thread") << endmsg;
 256                 return -1;
 257         }
 258
 259         have_peak_thread = true;
 260         return 0;
 261 }
 262
 263 void
 264 Source::stop_peak_thread ()
 265 {
 266         if (!have_peak_thread) {
 267                 return;
 268         }
 269
 270         void* status;
 271
 272         char c = (char) PeakRequest::Quit;
 273         ::write (peak_request_pipe[1], &c, 1);
 274         pthread_join (peak_thread, &status);
 275 }
 276
 277 void
 278 Source::queue_for_peaks (Source& source)
 279 {
 280         if (have_peak_thread) {
 281
 282                 LockMonitor lm (pending_peak_sources_lock, __LINE__, __FILE__);
 283
 284                 source.next_peak_clear_should_notify = true;
 285
 286                 if (find (pending_peak_sources.begin(),
 287                           pending_peak_sources.end(),
 288                           &source) == pending_peak_sources.end()) {
 289                         pending_peak_sources.push_back (&source);
 290                 }
 291
 292                 char c = (char) PeakRequest::Build;
 293                 ::write (peak_request_pipe[1], &c, 1);
 294         }
 295 }
 296
 297 void Source::clear_queue_for_peaks ()
 298 {
 299         /* this is done to cancel a group of running peak builds */
 300         if (have_peak_thread) {
 301                 LockMonitor lm (pending_peak_sources_lock, __LINE__, __FILE__);
 302                 pending_peak_sources.clear ();
 303         }
 304 }
 305
 306
 307 bool
 308 Source::peaks_ready (sigc::slot<void> the_slot) const
 309 {
 310         bool ret;
 311         LockMonitor lm (_lock, __LINE__, __FILE__);
 312
 313         /* check to see if the peak data is ready. if not
 314            connect the slot while still holding the lock.
 315         */
 316
 317         if (!(ret = _peaks_built)) {
 318                 PeaksReady.connect (the_slot);
 319         }
 320
 321         return ret;
 322 }
 323
 324 int
 325 Source::initialize_peakfile (bool newfile, string audio_path)
 326 {
 327         struct stat statbuf;
 328
 329         peakpath = peak_path (audio_path);
 330
 331         if (newfile) {
 332
 333                 if (!_build_peakfiles) {
 334                         return 0;
 335                 }
 336
 337                 _peaks_built = false;
 338
 339         } else {
 340
 341                 if (stat (peakpath.c_str(), &statbuf)) {
 342                         if (errno != ENOENT) {
 343                                 /* it exists in the peaks dir, but there is some kind of error */
 344
 345                                 error << string_compose(_("Source: cannot stat peakfile \"%1\""), peakpath) << endmsg;
 346                                 return -1;
 347                         }
 348
 349                         /* older sessions stored peaks in the same directory
 350                            as the audio. so check there as well.
 351                         */
 352
 353                         string oldpeakpath = old_peak_path (audio_path);
 354
 355                         if (stat (oldpeakpath.c_str(), &statbuf)) {
 356
 357                                 if (errno == ENOENT) {
 358
 359                                         statbuf.st_size = 0;
 360
 361                                 } else {
 362
 363                                         /* it exists in the audio dir , but there is some kind of error */
 364
 365                                         error << string_compose(_("Source: cannot stat peakfile \"%1\" or \"%2\""), peakpath, oldpeakpath) << endmsg;
 366                                         return -1;
 367                                 }
 368
 369                         } else {
 370
 371                                 /* we found it in the sound dir, where they lived once upon a time, in a land ... etc. */
 372
 373                                 peakpath = oldpeakpath;
 374                         }
 375
 376                 } else {
 377
 378                         /* we found it in the peaks dir */
 379                 }
 380
 381                 if (statbuf.st_size == 0) {
 382                         _peaks_built = false;
 383                 } else {
 384                         // Check if the audio file has changed since the peakfile was built.
 385                         struct stat stat_file;
 386                         int err = stat (audio_path.c_str(), &stat_file);
 387
 388                         if (!err && stat_file.st_mtime > statbuf.st_mtime){
 389                                 _peaks_built = false;
 390                         } else {
 391                                 _peaks_built = true;
 392                         }
 393                 }
 394         }
 395
 396         if ((peakfile = ::open (peakpath.c_str(), O_RDWR|O_CREAT, 0664)) < 0) {
 397                 error << string_compose(_("Source: cannot open peakpath \"%1\" (%2)"), peakpath, strerror (errno)) << endmsg;
 398                 return -1;
 399         }
 400
 401         if (!newfile && !_peaks_built && _build_missing_peakfiles && _build_peakfiles) {
 402                 build_peaks_from_scratch ();
 403         }
 404
 405         return 0;
 406 }
 407
 408 int
 409 Source::read_peaks (PeakData *peaks, jack_nframes_t npeaks, jack_nframes_t start, jack_nframes_t cnt, double samples_per_visual_peak) const
 410 {
 411         LockMonitor lm (_lock, __LINE__, __FILE__);
 412         double scale;
 413         double expected_peaks;
 414         PeakData::PeakDatum xmax;
 415         PeakData::PeakDatum xmin;
 416         int32_t to_read;
 417         uint32_t nread;
 418         jack_nframes_t zero_fill = 0;
 419         int ret = -1;
 420         PeakData* staging = 0;
 421         Sample* raw_staging = 0;
 422
 423         expected_peaks = (cnt / (double) frames_per_peak);
 424         scale = npeaks/expected_peaks;
 425
 426 #if 0
 427         cerr << "======>RP: npeaks = " << npeaks
 428              << " start = " << start
 429              << " cnt = " << cnt
 430              << " len = " << _length
 431              << "   samples_per_visual_peak =" << samples_per_visual_peak
 432              << " expected was " << expected_peaks << " ... scale = " << scale
 433              << " PD ptr = " << peaks
 434              <<endl;
 435
 436 #endif
 437
 438         /* fix for near-end-of-file conditions */
 439
 440         if (cnt > _length - start) {
 441                 // cerr << "too close to end @ " << _length << " given " << start << " + " << cnt << endl;
 442                 cnt = _length - start;
 443                 jack_nframes_t old = npeaks;
 444                 npeaks = min ((jack_nframes_t) floor (cnt / samples_per_visual_peak), npeaks);
 445                 zero_fill = old - npeaks;
 446         }
 447
 448         // cerr << "actual npeaks = " << npeaks << " zf = " << zero_fill << endl;
 449
 450         if (npeaks == cnt) {
 451
 452                 // cerr << "RAW DATA\n";
 453
 454                 /* no scaling at all, just get the sample data and duplicate it for
 455                    both max and min peak values.
 456                 */
 457
 458                 Sample* raw_staging = new Sample[cnt];
 459
 460                 if (read_unlocked (raw_staging, start, cnt) != cnt) {
 461                         error << _("cannot read sample data for unscaled peak computation") << endmsg;
 462                         return -1;
 463                 }
 464
 465                 for (jack_nframes_t i = 0; i < npeaks; ++i) {
 466                         peaks[i].max = raw_staging[i];
 467                         peaks[i].min = raw_staging[i];
 468                 }
 469
 470                 delete [] raw_staging;
 471
 472                 return 0;
 473         }
 474
 475         if (scale == 1.0) {
 476
 477                 // cerr << "DIRECT PEAKS\n";
 478
 479                 off_t first_peak_byte = (start / frames_per_peak) * sizeof (PeakData);
 480
 481                 if ((nread = ::pread (peakfile, peaks, sizeof (PeakData)* npeaks, first_peak_byte)) != sizeof (PeakData) * npeaks) {
 482                         cerr << "Source["
 483                              << _name
 484                              << "]: cannot read peaks from peakfile! (read only "
 485                              << nread
 486                              << " not "
 487                              << npeaks
 488                               << "at sample "
 489                              << start
 490                              << " = byte "
 491                              << first_peak_byte
 492                              << ')'
 493                              << endl;
 494                         return -1;
 495                 }
 496
 497                 if (zero_fill) {
 498                         memset (&peaks[npeaks], 0, sizeof (PeakData) * zero_fill);
 499                 }
 500
 501                 return 0;
 502         }
 503
 504
 505         jack_nframes_t tnp;
 506
 507         if (scale < 1.0) {
 508
 509                 // cerr << "DOWNSAMPLE\n";
 510
 511                 /* the caller wants:
 512
 513                     - more frames-per-peak (lower resolution) than the peakfile, or to put it another way,
 514                     - less peaks than the peakfile holds for the same range
 515
 516                     So, read a block into a staging area, and then downsample from there.
 517
 518                     to avoid confusion, I'll refer to the requested peaks as visual_peaks and the peakfile peaks as stored_peaks
 519                 */
 520
 521                 const uint32_t chunksize = (uint32_t) min (expected_peaks, 4096.0);
 522
 523                 staging = new PeakData[chunksize];
 524
 525                 /* compute the rounded up frame position  */
 526
 527                 jack_nframes_t current_frame = start;
 528                 jack_nframes_t current_stored_peak = (jack_nframes_t) ceil (current_frame / (double) frames_per_peak);
 529                 uint32_t       next_visual_peak  = (uint32_t) ceil (current_frame / samples_per_visual_peak);
 530                 double         next_visual_peak_frame = next_visual_peak * samples_per_visual_peak;
 531                 uint32_t       stored_peak_before_next_visual_peak = (jack_nframes_t) next_visual_peak_frame / frames_per_peak;
 532                 uint32_t       nvisual_peaks = 0;
 533                 uint32_t       stored_peaks_read = 0;
 534                 uint32_t       i = 0;
 535
 536                 /* handle the case where the initial visual peak is on a pixel boundary */
 537
 538                 current_stored_peak = min (current_stored_peak, stored_peak_before_next_visual_peak);
 539
 540                 while (nvisual_peaks < npeaks) {
 541
 542                         if (i == stored_peaks_read) {
 543
 544                                 uint32_t       start_byte = current_stored_peak * sizeof(PeakData);
 545                                 tnp = min ((_length/frames_per_peak - current_stored_peak), (jack_nframes_t) expected_peaks);
 546                                 to_read = min (chunksize, tnp);
 547
 548                                 if ((nread = ::pread (peakfile, staging, sizeof (PeakData) * to_read, start_byte))
 549                                     != sizeof (PeakData) * to_read) {
 550                                         cerr << "Source["
 551                                              << _name
 552                                              << "]: cannot read peak data from peakfile ("
 553                                              << nread
 554                                              << " peaks instead of "
 555                                              << to_read
 556                                              << ") ("
 557                                              << strerror (errno)
 558                                              << ')'
 559                                              << " at start_byte = " << start_byte
 560                                              << " _length = " << _length
 561                                              << " expected maxpeaks = " << (_length - current_frame)/frames_per_peak
 562                                              << " npeaks was " << npeaks
 563                                              << endl;
 564                                         goto out;
 565                                 }
 566
 567                                 i = 0;
 568                                 stored_peaks_read = nread / sizeof(PeakData);
 569                         }
 570
 571                         xmax = -1.0;
 572                         xmin = 1.0;
 573
 574                         while ((i < stored_peaks_read) && (current_stored_peak <= stored_peak_before_next_visual_peak)) {
 575
 576                                 xmax = max (xmax, staging[i].max);
 577                                 xmin = min (xmin, staging[i].min);
 578                                 ++i;
 579                                 ++current_stored_peak;
 580                                 --expected_peaks;
 581                         }
 582
 583                         peaks[nvisual_peaks].max = xmax;
 584                         peaks[nvisual_peaks].min = xmin;
 585                         ++nvisual_peaks;
 586                         ++next_visual_peak;
 587
 588                         //next_visual_peak_frame = min ((next_visual_peak * samples_per_visual_peak), (next_visual_peak_frame+samples_per_visual_peak) );
 589                         next_visual_peak_frame =  min ((double) start+cnt, (next_visual_peak_frame+samples_per_visual_peak) );
 590                         stored_peak_before_next_visual_peak = (uint32_t) next_visual_peak_frame / frames_per_peak;
 591                 }
 592
 593                 if (zero_fill) {
 594                         memset (&peaks[npeaks], 0, sizeof (PeakData) * zero_fill);
 595                 }
 596
 597                 ret = 0;
 598
 599         } else {
 600
 601                 // cerr << "UPSAMPLE\n";
 602
 603                 /* the caller wants
 604
 605                      - less frames-per-peak (more resolution)
 606                      - more peaks than stored in the Peakfile
 607
 608                    So, fetch data from the raw source, and generate peak
 609                    data on the fly.
 610                 */
 611
 612                 jack_nframes_t frames_read = 0;
 613                 jack_nframes_t current_frame = start;
 614                 jack_nframes_t i = 0;
 615                 jack_nframes_t nvisual_peaks = 0;
 616                 jack_nframes_t chunksize = (jack_nframes_t) min (cnt, (jack_nframes_t) 4096);
 617                 raw_staging = new Sample[chunksize];
 618
 619                 jack_nframes_t frame_pos = start;
 620                 double pixel_pos = floor (frame_pos / samples_per_visual_peak);
 621                 double next_pixel_pos = ceil (frame_pos / samples_per_visual_peak);
 622                 double pixels_per_frame = 1.0 / samples_per_visual_peak;
 623
 624                 xmin = 1.0;
 625                 xmax = -1.0;
 626
 627                 while (nvisual_peaks < npeaks) {
 628
 629                         if (i == frames_read) {
 630
 631                                 to_read = min (chunksize, (_length - current_frame));
 632
 633                                 if ((frames_read = read_unlocked (raw_staging, current_frame, to_read)) < 0) {
 634                                         error << string_compose(_("Source[%1]: peak read - cannot read %2 samples at offset %3")
 635                                                          , _name, to_read, current_frame)
 636                                               << endmsg;
 637                                         goto out;
 638                                 }
 639
 640                                 i = 0;
 641                         }
 642
 643                         xmax = max (xmax, raw_staging[i]);
 644                         xmin = min (xmin, raw_staging[i]);
 645                         ++i;
 646                         ++current_frame;
 647                         pixel_pos += pixels_per_frame;
 648
 649                         if (pixel_pos >= next_pixel_pos) {
 650
 651                                 peaks[nvisual_peaks].max = xmax;
 652                                 peaks[nvisual_peaks].min = xmin;
 653                                 ++nvisual_peaks;
 654                                 xmin = 1.0;
 655                                 xmax = -1.0;
 656
 657                                 next_pixel_pos = ceil (pixel_pos + 0.5);
 658                         }
 659                 }
 660
 661                 if (zero_fill) {
 662                         memset (&peaks[npeaks], 0, sizeof (PeakData) * zero_fill);
 663                 }
 664
 665                 ret = 0;
 666         }
 667
 668   out:
 669         if (staging) {
 670                 delete [] staging;
 671         }
 672
 673         if (raw_staging) {
 674                 delete [] raw_staging;
 675         }
 676
 677         return ret;
 678 }
 679
 680 #undef DEBUG_PEAK_BUILD
 681
 682 int
 683 Source::build_peaks ()
 684 {
 685         vector<PeakBuildRecord*> built;
 686         int status = -1;
 687         bool pr_signal = false;
 688         list<PeakBuildRecord*> copy;
 689
 690         {
 691                 LockMonitor lm (_lock, __LINE__, __FILE__);
 692                 copy = pending_peak_builds;
 693                 pending_peak_builds.clear ();
 694         }
 695
 696
 697 #ifdef DEBUG_PEAK_BUILD
 698         cerr << "build peaks with " << pending_peak_builds.size() << " requests pending\n";
 699 #endif
 700
 701         for (list<PeakBuildRecord *>::iterator i = copy.begin(); i != copy.end(); ++i) {
 702
 703                 if ((status = do_build_peak ((*i)->frame, (*i)->cnt)) != 0) {
 704                         unlink (peakpath.c_str());
 705                         break;
 706                 }
 707                 built.push_back (new PeakBuildRecord (*(*i)));
 708                 delete *i;
 709         }
 710
 711         {
 712                 LockMonitor lm (_lock, __LINE__, __FILE__);
 713
 714                 if (status == 0) {
 715                         _peaks_built = true;
 716
 717                         if (next_peak_clear_should_notify) {
 718                                 next_peak_clear_should_notify = false;
 719                                 pr_signal = true;
 720                         }
 721                 }
 722         }
 723
 724         if (status == 0) {
 725                 for (vector<PeakBuildRecord *>::iterator i = built.begin(); i != built.end(); ++i) {
 726                         PeakRangeReady ((*i)->frame, (*i)->cnt); /* EMIT SIGNAL */
 727                         delete *i;
 728                 }
 729
 730                 if (pr_signal) {
 731                         PeaksReady (); /* EMIT SIGNAL */
 732                 }
 733         }
 734
 735         return status;
 736 }
 737
 738 int
 739 Source::do_build_peak (jack_nframes_t first_frame, jack_nframes_t cnt)
 740 {
 741         jack_nframes_t current_frame;
 742         Sample buf[frames_per_peak];
 743         Sample xmin, xmax;
 744         uint32_t  peaki;
 745         PeakData* peakbuf;
 746         jack_nframes_t frames_read;
 747         jack_nframes_t frames_to_read;
 748         off_t first_peak_byte;
 749         int ret = -1;
 750
 751 #ifdef DEBUG_PEAK_BUILD
 752         cerr << pthread_self() << ": " << _name << ": building peaks for " << first_frame << " to " << first_frame + cnt - 1 << endl;
 753 #endif
 754
 755         first_peak_byte = (first_frame / frames_per_peak) * sizeof (PeakData);
 756
 757 #ifdef DEBUG_PEAK_BUILD
 758         cerr << "seeking to " << first_peak_byte << " before writing new peak data\n";
 759 #endif
 760
 761         current_frame = first_frame;
 762         peakbuf = new PeakData[(cnt/frames_per_peak)+1];
 763         peaki = 0;
 764
 765         while (cnt) {
 766
 767                 frames_to_read = min (frames_per_peak, cnt);
 768
 769                 if ((frames_read = read_unlocked (buf, current_frame, frames_to_read)) != frames_to_read) {
 770                         error << string_compose(_("%1: could not write read raw data for peak computation (%2)"), _name, strerror (errno)) << endmsg;
 771                         goto out;
 772                 }
 773
 774                 xmin = buf[0];
 775                 xmax = buf[0];
 776
 777                 for (jack_nframes_t n = 1; n < frames_read; ++n) {
 778                         xmax = max (xmax, buf[n]);
 779                         xmin = min (xmin, buf[n]);
 780
 781 //                      if (current_frame < frames_read) {
 782 //                              cerr << "sample = " << buf[n] << " max = " << xmax << " min = " << xmin << " max of 2 = " << max (xmax, buf[n]) << endl;
 783 //                      }
 784                 }
 785
 786                 peakbuf[peaki].max = xmax;
 787                 peakbuf[peaki].min = xmin;
 788                 peaki++;
 789
 790                 current_frame += frames_read;
 791                 cnt -= frames_read;
 792         }
 793
 794         if (::pwrite (peakfile, peakbuf, sizeof (PeakData) * peaki, first_peak_byte) != (ssize_t) sizeof (PeakData) * peaki) {
 795                 error << string_compose(_("%1: could not write peak file data (%2)"), _name, strerror (errno)) << endmsg;
 796                 goto out;
 797         }
 798
 799         ret = 0;
 800
 801   out:
 802         delete [] peakbuf;
 803         return ret;
 804 }
 805
 806 void
 807 Source::build_peaks_from_scratch ()
 808 {
 809         LockMonitor lp (_lock, __LINE__, __FILE__);
 810
 811         next_peak_clear_should_notify = true;
 812         pending_peak_builds.push_back (new PeakBuildRecord (0, _length));
 813         queue_for_peaks (*this);
 814 }
 815
 816 bool
 817 Source::file_changed (string path)
 818 {
 819         struct stat stat_file;
 820         struct stat stat_peak;
 821
 822         int e1 = stat (path.c_str(), &stat_file);
 823         int e2 = stat (peak_path(path).c_str(), &stat_peak);
 824
 825         if (!e1 && !e2 && stat_file.st_mtime > stat_peak.st_mtime){
 826                 return true;
 827         } else {
 828                 return false;
 829         }
 830 }
 831
 832 void
 833 Source::use ()
 834 {
 835         _use_cnt++;
 836 }
 837
 838 void
 839 Source::release ()
 840 {
 841         if (_use_cnt) --_use_cnt;
 842 }