view data/fileio/AudioFileSizeEstimator.h @ 1833:21c792334c2e sensible-delimited-data-strings

Rewrite all the DelimitedDataString stuff so as to return vectors of individual cell strings rather than having the classes add the delimiters themselves. Rename accordingly to names based on StringExport. Take advantage of this in the CSV writer code so as to properly quote cells that contain delimiter characters.

/* -*- 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 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_SIZE_ESTIMATOR_H
#define AUDIO_FILE_SIZE_ESTIMATOR_H

#include "base/BaseTypes.h"
#include "data/fileio/FileSource.h"

/**
 * Estimate the number of samples in an audio file. For many
 * compressed files this returns only a very approximate estimate,
 * based on a rough estimate of compression ratio. Initially we're
 * only aiming for a conservative estimate for purposes like "will
 * this file fit in memory?" (and if unsure, say no).
 */
class AudioFileSizeEstimator
{
public:
    /**
     * Return an estimate of the number of samples (across all
     * channels) in the given audio file, once it has been decoded and
     * (if applicable) resampled to the given rate.
     *
     * This function is intended to be reasonably fast -- it may open
     * the file, but it should not do any decoding. (However, if the
     * file source is remote, it will probably be downloaded in its
     * entirety before anything can be estimated.)
     *
     * The returned value is an estimate, and is deliberately usually
     * on the high side. If the estimator has no idea at all, this
     * will return 0.
     */
    static sv_frame_t estimate(FileSource source,
                               sv_samplerate_t targetRate = 0);
};

#endif