reverse.cc

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/*
    Copyright (C) 2004 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 <algorithm>

#include "ardour/audioregion.h"
#include "ardour/audiosource.h"
#include "ardour/reverse.h"
#include "ardour/types.h"

using namespace std;
using namespace ARDOUR;

namespace ARDOUR { class Progress; class Session; }

Reverse::Reverse (Session& s)
        : Filter (s)
{
}

Reverse::~Reverse ()
{
}

int
Reverse::run (boost::shared_ptr<Region> r, Progress*)
{
        SourceList nsrcs;
        SourceList::iterator si;
        framecnt_t blocksize = 256 * 1024;
        Sample* buf = 0;
        framepos_t fpos;
        framepos_t fstart;
        framecnt_t to_read;
        int ret = -1;

        boost::shared_ptr<AudioRegion> region = boost::dynamic_pointer_cast<AudioRegion>(r);
        if (!region)
                return ret;

        /* create new sources */

        if (make_new_sources (region, nsrcs)) {
                goto out;
        }

        fstart = region->start();

        if (blocksize > region->length()) {
                blocksize = region->length();
        }

        fpos = max (fstart, (fstart + region->length() - blocksize));

        buf = new Sample[blocksize];
        to_read = blocksize;

        /* now read it backwards */

        while (to_read) {

                uint32_t n;

                for (n = 0, si = nsrcs.begin(); n < region->n_channels(); ++n, ++si) {

                        /* read it in directly from the source */

                        if (region->audio_source (n)->read (buf, fpos, to_read) != to_read) {
                                goto out;
                        }

                        /* swap memory order */

                        for (framecnt_t i = 0; i < to_read/2; ++i) {
                                swap (buf[i],buf[to_read-1-i]);
                        }

                        /* write it out */

                        boost::shared_ptr<AudioSource> asrc(boost::dynamic_pointer_cast<AudioSource>(*si));

                        if (asrc && asrc->write (buf, to_read) != to_read) {
                                goto out;
                        }
                }

                if (fpos > fstart + blocksize) {
                        fpos -= to_read;
                        to_read = blocksize;
                } else {
                        to_read = fpos - fstart;
                        fpos = fstart;
                }
        };

        ret = finish (region, nsrcs);

  out:

        delete [] buf;

        if (ret) {
                for (si = nsrcs.begin(); si != nsrcs.end(); ++si) {
                        boost::shared_ptr<AudioSource> asrc(boost::dynamic_pointer_cast<AudioSource>(*si));
                        asrc->mark_for_remove ();
                }
        }

        return ret;
}