lbajardsilogic@0: /* -*- c-basic-offset: 4 indent-tabs-mode: nil -*-  vi:set ts=8 sts=4 sw=4: */
lbajardsilogic@0: 
lbajardsilogic@0: /*
lbajardsilogic@0:     Sonic Visualiser
lbajardsilogic@0:     An audio file viewer and annotation editor.
lbajardsilogic@0:     Centre for Digital Music, Queen Mary, University of London.
lbajardsilogic@0:     This file copyright 2006 QMUL.
lbajardsilogic@0:     
lbajardsilogic@0:     This program is free software; you can redistribute it and/or
lbajardsilogic@0:     modify it under the terms of the GNU General Public License as
lbajardsilogic@0:     published by the Free Software Foundation; either version 2 of the
lbajardsilogic@0:     License, or (at your option) any later version.  See the file
lbajardsilogic@0:     COPYING included with this distribution for more information.
lbajardsilogic@0: */
lbajardsilogic@0: 
lbajardsilogic@0: #ifndef _STORAGE_ADVISER_H_
lbajardsilogic@0: #define _STORAGE_ADVISER_H_
lbajardsilogic@0: 
lbajardsilogic@0: /**
lbajardsilogic@0:  * A utility class designed to help decide whether to store cache data
lbajardsilogic@0:  * (for example FFT outputs) in memory or on disk in the TempDirectory.
lbajardsilogic@0:  * This is basically a compendium of simple rules of thumb.
lbajardsilogic@0:  */
lbajardsilogic@0: 
lbajardsilogic@0: class StorageAdviser
lbajardsilogic@0: {
lbajardsilogic@0: public:
lbajardsilogic@0:     // pass to recommend() zero or more of these OR'd together
lbajardsilogic@0:     enum Criteria {
lbajardsilogic@0:         NoCriteria           = 0,
lbajardsilogic@0:         SpeedCritical        = 1,
lbajardsilogic@0:         PrecisionCritical    = 2,
lbajardsilogic@0:         LongRetentionLikely  = 4,
lbajardsilogic@0:         FrequentLookupLikely = 8
lbajardsilogic@0:     };
lbajardsilogic@0: 
lbajardsilogic@0:     // recommend() returns one or two of these OR'd together
lbajardsilogic@0:     enum Recommendation {
lbajardsilogic@0:         NoRecommendation   = 0,
lbajardsilogic@0:         UseMemory          = 1, // Disc is strongly contraindicated
lbajardsilogic@0:         PreferMemory       = 2, // Either would do; memory probably better
lbajardsilogic@0:         PreferDisc         = 4, // Either would do; disc probably better
lbajardsilogic@0:         UseDisc            = 8, // Probably won't fit in memory
lbajardsilogic@0:         ConserveSpace      = 16,// Whatever you choose, keep it compact
lbajardsilogic@0:         UseAsMuchAsYouLike = 32 // Take my advice and there'll be space for all
lbajardsilogic@0:     };
lbajardsilogic@0: 
lbajardsilogic@0:     /**
lbajardsilogic@0:      * Recommend where to store some data, given certain storage and
lbajardsilogic@0:      * recall criteria.  The minimum size is the approximate amount of
lbajardsilogic@0:      * data in kilobytes that will be stored if the recommendation is
lbajardsilogic@0:      * to ConserveSpace; the maximum size is approximately the amount
lbajardsilogic@0:      * that will be used if UseAsMuchAsYouLike is returned.
lbajardsilogic@0:      *
lbajardsilogic@0:      * May throw InsufficientDiscSpace exception if there appears to
lbajardsilogic@0:      * be nowhere the minimum amount of data can be stored.
lbajardsilogic@0:      */
lbajardsilogic@0:     static Recommendation recommend(Criteria criteria,
lbajardsilogic@0:                                     int minimumSize,
lbajardsilogic@0:                                     int maximumSize);
lbajardsilogic@0: 
lbajardsilogic@0:     enum AllocationArea {
lbajardsilogic@0:         MemoryAllocation,
lbajardsilogic@0:         DiscAllocation
lbajardsilogic@0:     };
lbajardsilogic@0: 
lbajardsilogic@0:     /**
lbajardsilogic@0:      * Specify that we are planning to use a given amount of storage
lbajardsilogic@0:      * (in kilobytes), but haven't allocated it yet.
lbajardsilogic@0:      */
lbajardsilogic@0:     static void notifyPlannedAllocation(AllocationArea area, int size);
lbajardsilogic@0: 
lbajardsilogic@0:     /**
lbajardsilogic@0:      * Specify that we have now allocated, or abandoned the allocation
lbajardsilogic@0:      * of, the given amount (in kilobytes) of a storage area that was
lbajardsilogic@0:      * previously notified using notifyPlannedAllocation.
lbajardsilogic@0:      */
lbajardsilogic@0:     static void notifyDoneAllocation(AllocationArea area, int size);
lbajardsilogic@0: 
lbajardsilogic@0: private:
lbajardsilogic@0:     static long m_discPlanned;
lbajardsilogic@0:     static long m_memoryPlanned;
lbajardsilogic@0: };
lbajardsilogic@0: 
lbajardsilogic@0: #endif
lbajardsilogic@0: