StorageAdviser.h

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/* -*- 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 QMUL.
    
    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 SV_STORAGE_ADVISER_H
#define SV_STORAGE_ADVISER_H

#include <cstdlib>

#include <QString>

class StorageAdviser
{
public:
    // pass to recommend() zero or more of these OR'd together
    enum Criteria {
        NoCriteria           = 0,
        SpeedCritical        = 1,
        PrecisionCritical    = 2,
        LongRetentionLikely  = 4,
        FrequentLookupLikely = 8
    };

    // recommend() returns one or two of these OR'd together
    enum Recommendation {
        NoRecommendation   = 0,
        UseMemory          = 1, // Disc is strongly contraindicated
        PreferMemory       = 2, // Either would do; memory probably better
        PreferDisc         = 4, // Either would do; disc probably better
        UseDisc            = 8, // Probably won't fit in memory
        ConserveSpace      = 16,// Whatever you choose, keep it compact
        UseAsMuchAsYouLike = 32 // Take my advice and there'll be space for all
    };

    static Recommendation recommend(Criteria criteria,
                                    size_t minimumSize,
                                    size_t maximumSize);

    enum AllocationArea {
        MemoryAllocation,
        DiscAllocation
    };

    static void notifyPlannedAllocation(AllocationArea area, size_t size);

    static void notifyDoneAllocation(AllocationArea area, size_t size);

    static void setFixedRecommendation(Recommendation recommendation);

private:
    static size_t m_discPlanned;
    static size_t m_memoryPlanned;
    static Recommendation m_baseRecommendation;

    enum StorageStatus {
        Unknown,
        Insufficient,
        Marginal,
        Sufficient
    };

    static QString criteriaToString(int);
    static QString recommendationToString(int);
    static QString storageStatusToString(StorageStatus);
};

#endif