framecache.h

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#ifndef FRAMECACHE_H
#define FRAMECACHE_H


#include "arraylist.h"
#include "mutex.inc"
#include "vframe.inc"


#include <stdint.h>

// Simply a table of images described by frame position and dimensions.
// The frame position is relative to the frame rate of the source file.
// This object is held by File.  CICache scans all the files for
// frame caches and deletes what's needed to maintain the cache size.

class FrameCacheItem
{
public:
        FrameCacheItem();
        ~FrameCacheItem();

        VFrame *data;
        int64_t position;
        double frame_rate;
// Number of last get or put operation involving this object.
        int age;
};

class FrameCache
{
public:
        FrameCache();
        ~FrameCache();

// Returns 1 if frame exists in cache and copies it to the frame argument.
        int get_frame(VFrame *frame, 
                int64_t position,
                double frame_rate);
// Returns pointer to cache entry if frame exists or 0.
// If a frame is found, the frame cache is left in the locked state until 
// unlock is called.  If nothing is found, the frame cache is unlocked before
// returning.  This keeps the item from being deleted.
        VFrame* get_frame_ptr(int64_t position,
                double frame_rate,
                int color_model,
                int w,
                int h);
        void unlock();
// Puts the frame in cache.
// use_copy - if 1 a copy of the frame is made.  if 0 the argument is stored.
// The copy of the frame is deleted by FrameCache in a future delete_oldest.
        void put_frame(VFrame *frame, 
                int64_t position,
                double frame_rate,
                int use_copy);

// Delete oldest item.  Return 0 if successful.  Return 1 if nothing to delete.
        int delete_oldest();

// Calculate current size of cache in bytes
        int64_t get_memory_usage();
        void dump();




private:
// Return 1 if matching frame exists.
// Return 0 if not.
        int frame_exists(VFrame *format,
                int64_t position,
                double frame_rate,
                int *item_return);
        int FrameCache::frame_exists(int64_t position, 
                double frame_rate,
                int color_model,
                int w,
                int h,
                int *item_return);

        Mutex *lock;
// Current get or put operation since creation of FrameCache object
        int current_age;
        ArrayList<FrameCacheItem*> items;
// Maximum size of cache in bytes.
        int64_t max_bytes;
};



#endif

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