/**
- * \file mlt_profile.c
+ * \file mlt_cache.c
* \brief least recently used cache
* \see mlt_profile_s
*
- * Copyright (C) 2007-2009 Ushodaya Enterprises Limited
+ * Copyright (C) 2007-2012 Ushodaya Enterprises Limited
* \author Dan Dennedy <dan@dennedy.org>
*
* This library is free software; you can redistribute it and/or
#include "mlt_log.h"
#include "mlt_properties.h"
#include "mlt_cache.h"
+#include "mlt_frame.h"
#include <stdlib.h>
#include <pthread.h>
}
/** Put a chunk of data in the cache.
+ *
+ * This function and mlt_cache_get() are not scalable with a large volume
+ * of unique \p object paramter values. Therefore, it does not make sense
+ * to use it for a frame/image cache using the frame position for \p object.
+ * Instead, use mlt_cache_put_frame() for that.
*
* \public \memberof mlt_cache_s
* \param cache a cache object
return result;
}
+
+/** Shuffle the cache entries between the two arrays and return the frame for a position.
+ *
+ * \private \memberof mlt_cache_s
+ * \param cache a cache object
+ * \param position the position of the frame that you want
+ * \return a frame if there was a hit or NULL for a miss
+ */
+
+static mlt_frame* shuffle_get_frame( mlt_cache cache, mlt_position position )
+{
+ int i = cache->count;
+ int j = cache->count - 1;
+ mlt_frame *hit = NULL;
+ mlt_frame *alt = (mlt_frame*) ( cache->current == cache->A ? cache->B : cache->A );
+
+ if ( cache->count > 0 && cache->count < cache->size )
+ {
+ // first determine if we have a hit
+ while ( i-- && !hit )
+ {
+ mlt_frame *o = (mlt_frame*) &cache->current[ i ];
+ if ( mlt_frame_get_position( *o ) == position )
+ hit = o;
+ }
+ // if there was no hit, we will not be shuffling out an entry
+ // and are still filling the cache
+ if ( !hit )
+ ++j;
+ // reset these
+ i = cache->count;
+ hit = NULL;
+ }
+
+ // shuffle the existing entries to the alternate array
+ while ( i-- )
+ {
+ mlt_frame *o = (mlt_frame*) &cache->current[ i ];
+
+ if ( !hit && mlt_frame_get_position( *o ) == position )
+ {
+ hit = o;
+ }
+ else if ( j > 0 )
+ {
+ alt[ --j ] = *o;
+// mlt_log( NULL, MLT_LOG_DEBUG, "%s: shuffle %d = %p\n", __FUNCTION__, j, alt[j] );
+ }
+ }
+ return hit;
+}
+
+/** Put a frame in the cache.
+ *
+ * Unlike mlt_cache_put() this version is more suitable for caching frames
+ * and their data - like images. However, this version does not use reference
+ * counting and garbage collection. Rather, frames are cloned with deep copy
+ * to avoid those things.
+ *
+ * \public \memberof mlt_cache_s
+ * \param cache a cache object
+ * \param frame the frame to cache
+ * \see mlt_frame_get_frame
+ */
+
+void mlt_cache_put_frame( mlt_cache cache, mlt_frame frame )
+{
+ pthread_mutex_lock( &cache->mutex );
+ mlt_frame *hit = shuffle_get_frame( cache, mlt_frame_get_position( frame ) );
+ mlt_frame *alt = (mlt_frame*) ( cache->current == cache->A ? cache->B : cache->A );
+
+ // add the frame to the cache
+ if ( hit )
+ {
+ // release the old data
+ mlt_frame_close( *hit );
+ // the MRU end gets the updated data
+ hit = &alt[ cache->count - 1 ];
+ }
+ else if ( cache->count < cache->size )
+ {
+ // more room in cache, add it to MRU end
+ hit = &alt[ cache->count++ ];
+ }
+ else
+ {
+ // release the entry at the LRU end
+ mlt_frame_close( cache->current[0] );
+
+ // The MRU end gets the new item
+ hit = &alt[ cache->count - 1 ];
+ }
+ *hit = mlt_frame_clone( frame, 1 );
+ mlt_log( NULL, MLT_LOG_DEBUG, "%s: put %d = %p\n", __FUNCTION__, cache->count - 1, frame );
+
+ // swap the current array
+ cache->current = (void**) alt;
+ pthread_mutex_unlock( &cache->mutex );
+}
+
+/** Get a frame from the cache.
+ *
+ * You must call mlt_frame_close() on the frame you receive from this.
+ *
+ * \public \memberof mlt_cache_s
+ * \param cache a cache object
+ * \param position the position of the frame that you want
+ * \return a frame if found or NULL if not found or has been flushed from the cache
+ * \see mlt_frame_put_frame
+ */
+
+mlt_frame mlt_cache_get_frame( mlt_cache cache, mlt_position position )
+{
+ mlt_frame result = NULL;
+ pthread_mutex_lock( &cache->mutex );
+ mlt_frame *hit = shuffle_get_frame( cache, position );
+ mlt_frame *alt = (mlt_frame*) ( cache->current == cache->A ? cache->B : cache->A );
+
+ if ( hit )
+ {
+ // copy the hit to the MRU end
+ alt[ cache->count - 1 ] = *hit;
+ hit = &alt[ cache->count - 1 ];
+
+ result = mlt_frame_clone( *hit, 1 );
+ mlt_log( NULL, MLT_LOG_DEBUG, "%s: get %d = %p\n", __FUNCTION__, cache->count - 1, *hit );
+
+ // swap the current array
+ cache->current = (void**) alt;
+ }
+ pthread_mutex_unlock( &cache->mutex );
+
+ return result;
+}
projects / mlt / blobdiff