detectorcache::DetectorCache Class Reference

Cache results from a detectorbank. More...

#include <detectorcache.h>

Inheritance diagram for detectorcache::DetectorCache:

Collaboration diagram for detectorcache::DetectorCache:

Public Member Functions
	DetectorCache (Producer &p, const std::size_t num_segs, const std::size_t seg_len, const std::size_t start_chan, const std::size_t num_chans)
	Construct a DetectorCache. More...
	DetectorCache (detectorcache::Producer &p, const std::size_t num_segs, const std::size_t seg_len, const std::size_t start_chan=0)
	Construct a DetectorCache with default start and size. More...
result_t	getResultItem (long int ch, long int n)
	Return the absolute value of the DetectorBank output at the given channel and sample time. More...
std::size_t	getPreviousResults (const std::size_t chan, const std::size_t currentSample, result_t *samples, std::size_t numSamples)
	Efficiently copy a range of cached data from a given cache channel to the designated target. More...
std::size_t	end (void)
	Get the total number of samples the cache can return. More...
parameter_t	getSR (void) const
	Get the sample rate of the associtaed DetectorBank.
std::size_t	getChans (void)
	Get the number of channels in the cache.
Public Member Functions inherited from slidingbuffer::SlidingBuffer< result_t *, detectorcache::Segment, detectorcache::Producer >
	SlidingBuffer (detectorcache::Producer &sp, const std::size_t max_segs, const std::size_t seg_size)
	Create a SlidingBuffer. More...
virtual	~SlidingBuffer ()
	Destructor.
result_t * &	operator[] (long int idx)
	Access an element of the SlidingBuffer. More...

Protected Attributes
const std::size_t	chans
	Number of analysis channels.
const std::size_t	seg_len
	Number of audio samples per segment.
Producer &	p
	This Producer for this DetectorCache.
const std::size_t	start_chan
	Channel in DetectorBank at which to start.
Protected Attributes inherited from slidingbuffer::SlidingBuffer< result_t *, detectorcache::Segment, detectorcache::Producer >
std::size_t	origin
	Lowest index in buffer.
const std::size_t	max_segs
	The largest number of segments in the buffer A history of at least \(seg_size\cdot(max_segs-1)\) entities will be made available subject to sufficient data having been read from the data stream.
const std::size_t	seg_size
	The number of entities in each segment.
std::deque< detectorcache::Segment *, UniqueAllocator< detectorcache::Segment *> >	segs
	Segments held by the buffer.
detectorcache::Producer &	sp
	The producer to call to fill a segment.

Detailed Description

Cache results from a detectorbank.

Definition at line 168 of file detectorcache.h.

Constructor & Destructor Documentation

DetectorCache() [1/2]

detectorcache::DetectorCache::DetectorCache	(	Producer &	p,
		const std::size_t	num_segs,
		const std::size_t	seg_len,
		const std::size_t	start_chan,
		const std::size_t	num_chans
	)

Construct a DetectorCache.

Parameters

p	The segment producer for this cache.
num_segs	Number of historical segments to remember.
seg_len	Number of audio samples per segment.
start_chan	First channel for this cache.
num_chans	Number of channels in this cache.

DetectorCache() [2/2]

detectorcache::DetectorCache::DetectorCache ( detectorcache::Producer &  p, const std::size_t  num_segs, const std::size_t  seg_len, const std::size_t  start_chan = 0  )

inline

Construct a DetectorCache with default start and size.

If the start channel parameter is omitted, assume 0. If the number of channels is omitted, use the value obtained by querying the supplied producer.

Definition at line 194 of file detectorcache.h.

Member Function Documentation

end()

std::size_t detectorcache::DetectorCache::end ( void  )

inline

Get the total number of samples the cache can return.

Returns

Length of the associated DetectorBank's audio input buffer in samples.

Definition at line 256 of file detectorcache.h.

getPreviousResults()

std::size_t detectorcache::DetectorCache::getPreviousResults	(	const std::size_t	chan,
		const std::size_t	currentSample,
		result_t *	samples,
		std::size_t	numSamples
	)

Efficiently copy a range of cached data from a given cache channel to the designated target.

The caller must allocate sufficient memory for the requested number of result_t data, and pass its address and the number of results desired. The supplied memory is filled with results from the detectorcache, ending at the given index.

This permits an external onset detecting algorithm to request the history of a detector channel once an onset threshold has been achieved in order to refine its estimate of the precise onset time.

Parameters

chan	Channel for which to provide history
currentSample	Index from which to roll back
samples	Pointer to target storage
numSamples	Number of samples to copy to target (currentSample being the last)

Returns

The number of samples actually copied.

Exceptions

slidingbuffer::ExpiredIndexException

If the requested number of samples exceeds that in the cache.

See also

DetectorCacheDesign

getResultItem()

result_t detectorcache::DetectorCache::getResultItem	(	long int	ch,
		long int	n
	)

Return the absolute value of the DetectorBank output at the given channel and sample time.

The sample time must be positive, and not be too old to have been deleted by the detectorcache.

If the sample time is negative, a slidingbuffer::NegativeIndexException will be thrown. This must be done explicitly here, as the DetectorCache is a 2D representation of a SlidingBuffer, where the channel is the SlidingBuffer index, so only a negative channel will result in a NegativeIndexException thrown by the SlidingBuffer itself.

If the sample time exceeds the length of the audio buffer, getResultItem will return 0.

Parameters

ch	Channel number of the output sample.
n	Sample's time-index.

Returns

The value of the detector's output at that time.

Exceptions

slidingbuffer::NegativeIndexException

If n < 0

---

The documentation for this class was generated from the following file:

• /home/keziah/onsets/DetectorBank/src/detectorcache.h