libs/ardour/reverse.cc

   1 /*
   2     Copyright (C) 2004 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 */
  19
  20 #include <algorithm>
  21
  22 #include "pbd/basename.h"
  23
  24 #include "ardour/types.h"
  25 #include "ardour/reverse.h"
  26 #include "ardour/audiofilesource.h"
  27 #include "ardour/session.h"
  28 #include "ardour/audioregion.h"
  29
  30 #include "i18n.h"
  31
  32 using namespace std;
  33 using namespace ARDOUR;
  34
  35 Reverse::Reverse (Session& s)
  36         : Filter (s)
  37 {
  38 }
  39
  40 Reverse::~Reverse ()
  41 {
  42 }
  43
  44 int
  45 Reverse::run (boost::shared_ptr<Region> r)
  46 {
  47         SourceList nsrcs;
  48         SourceList::iterator si;
  49         nframes_t blocksize = 256 * 1024;
  50         Sample* buf = 0;
  51         nframes_t fpos;
  52         nframes_t fstart;
  53         nframes_t to_read;
  54         int ret = -1;
  55
  56         boost::shared_ptr<AudioRegion> region = boost::dynamic_pointer_cast<AudioRegion>(r);
  57         if (!region)
  58                 return ret;
  59
  60         /* create new sources */
  61
  62         if (make_new_sources (region, nsrcs)) {
  63                 goto out;
  64         }
  65
  66         fstart = region->start();
  67
  68         if (blocksize > region->length()) {
  69                 blocksize = region->length();
  70         }
  71
  72         fpos = max (fstart, (fstart + region->length() - blocksize));
  73
  74         buf = new Sample[blocksize];
  75         to_read = blocksize;
  76
  77         /* now read it backwards */
  78
  79         while (to_read) {
  80
  81                 uint32_t n;
  82
  83                 for (n = 0, si = nsrcs.begin(); n < region->n_channels(); ++n, ++si) {
  84
  85                         /* read it in directly from the source */
  86
  87                         if (region->audio_source (n)->read (buf, fpos, to_read) != to_read) {
  88                                 goto out;
  89                         }
  90
  91                         /* swap memory order */
  92
  93                         for (nframes_t i = 0; i < to_read/2; ++i) {
  94                                 swap (buf[i],buf[to_read-1-i]);
  95                         }
  96
  97                         /* write it out */
  98
  99                         boost::shared_ptr<AudioSource> asrc(boost::dynamic_pointer_cast<AudioSource>(*si));
 100
 101                         if (asrc && asrc->write (buf, to_read) != to_read) {
 102                                 goto out;
 103                         }
 104                 }
 105
 106                 if (fpos > fstart + blocksize) {
 107                         fpos -= to_read;
 108                         to_read = blocksize;
 109                 } else {
 110                         to_read = fpos - fstart;
 111                         fpos = fstart;
 112                 }
 113         };
 114
 115         ret = finish (region, nsrcs);
 116
 117   out:
 118
 119         delete [] buf;
 120
 121         if (ret) {
 122                 for (si = nsrcs.begin(); si != nsrcs.end(); ++si) {
 123                         boost::shared_ptr<AudioSource> asrc(boost::dynamic_pointer_cast<AudioSource>(*si));
 124                         asrc->mark_for_remove ();
 125                 }
 126         }
 127
 128         return ret;
 129 }