audio_buffer.cc

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/*
    Copyright (C) 2006-2007 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 <errno.h>

#include "ardour/audio_buffer.h"
#include "pbd/error.h"
#include "pbd/malign.h"

#include "i18n.h"

using namespace PBD;
using namespace ARDOUR;

AudioBuffer::AudioBuffer(size_t capacity)
        : Buffer (DataType::AUDIO)
        , _owns_data (false)
        , _data (0)
{
        if (capacity) {
                _owns_data = true; // prevent resize() from gagging
                resize (capacity);
                _silent = false; // force silence on the intial buffer state
                clear ();
        }
}

AudioBuffer::~AudioBuffer()
{
        if (_owns_data)
                free(_data);
}

void
AudioBuffer::resize (size_t size)
{
        if (!_owns_data) {
                /* XXX how the hell is this enforced? */
                _capacity = size;
                return;
        }

        if (_data && size < _capacity) {
                /* buffer is already large enough */
                return;
        }

        free (_data);

        cache_aligned_malloc ((void**) &_data, sizeof (Sample) * size);

        _capacity = size;
        _silent = false;
}

bool
AudioBuffer::check_silence (pframes_t nframes, pframes_t& n) const
{
        for (n = 0; n < nframes; ++n) {
                if (_data[n] != Sample (0)) {
                        return false;
                }
        }
        return true;
}

void
AudioBuffer::silence (framecnt_t len, framecnt_t offset) {

        if (!_silent) {
                assert(_capacity > 0);
                assert(offset + len <= _capacity);
                memset(_data + offset, 0, sizeof (Sample) * len);
                if (len == _capacity) {
                        _silent = true;
                }
        }
        _written = true;
}