annotate data/fileio/AudioFileReaderFactory.h @ 335:02d2ad95ea52 spectrogram-cache-rejig

* Get storage advice for each cache in an FFT data server.  Allows us to be
  more confident about the actual memory situation and cut over from memory
  to disc part way through an FFT calculation if necessary.  StorageAdviser
  is now a bit too optimistic though (it's too keen to allocate large numbers
  of small blocks in memory).

/* -*- c-basic-offset: 4 indent-tabs-mode: nil -*-  vi:set ts=8 sts=4 sw=4: */

/*
    Sonic Visualiser
    An audio file viewer and annotation editor.
    Centre for Digital Music, Queen Mary, University of London.
    This file copyright 2006 Chris Cannam.
    
    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.  See the file
    COPYING included with this distribution for more information.
*/

#ifndef _AUDIO_FILE_READER_FACTORY_H_
#define _AUDIO_FILE_READER_FACTORY_H_

#include <QString>

#include "FileSource.h"

class AudioFileReader;

class AudioFileReaderFactory
{
public:
    /**
     * Return the file extensions that we have audio file readers for,
     * in a format suitable for use with QFileDialog.  For example,
     * "*.wav *.aiff *.ogg".
     */
    static QString getKnownExtensions();

    /**
     * Return an audio file reader initialised to the file at the
     * given path, or NULL if no suitable reader for this path is
     * available or the file cannot be opened.
     *
     * If targetRate is non-zero, the file will be resampled to that
     * rate (transparently).  You can query reader->getNativeRate()
     * if you want to find out whether the file is being resampled
     * or not.
     *
     * Caller owns the returned object and must delete it after use.
     */
    static AudioFileReader *createReader(FileSource source,
                                         size_t targetRate = 0);

    /**
     * Return an audio file reader initialised to the file at the
     * given path, or NULL if no suitable reader for this path is
     * available or the file cannot be opened.  If the reader supports
     * threaded decoding, it will be used and the file decoded in a
     * background thread.
     *
     * If targetRate is non-zero, the file will be resampled to that
     * rate (transparently).  You can query reader->getNativeRate()
     * if you want to find out whether the file is being resampled
     * or not.
     *
     * Caller owns the returned object and must delete it after use.
     */
    static AudioFileReader *createThreadingReader(FileSource source,
                                                  size_t targetRate = 0);

protected:
    static AudioFileReader *create(FileSource source,
                                   size_t targetRate,
                                   bool threading);
};

#endif