Rack/plugins/community/repos/squinkylabs-plug1/dsp/utils/ObjectCache.h

#pragma once


#include "LookupTable.h"

/**
 * This class creates objects and caches them.
 * Objects in the cache only stay alive as long as there is a reference to the object,
 * If all refs go away, the object will be deleted.
 *
 * All accessors return shared pointers to make the lifetime management easy.
 * Clients are free to use the shared_ptr directly, or may use the raw pointer,
 * as long as the client holds onto the reference.
 */

template <typename T>
class ObjectCache
{
public:
    static std::shared_ptr<LookupTableParams<T>> getBipolarAudioTaper();
    static std::shared_ptr<LookupTableParams<T>> getSinLookup();

    /**
     * 2 ** x, not scaled or shifted in any manner, but tables
     * selected to span a "reasonable" range when used as frequencies
     (4 Hz to 40kHz)
     * Exp2 lookup is 2 ** x.
     * Domain = {2 .. 15(+)}
     * Range = {4 .. 40000}
     * accuracy = 1 cent (1V/octave)
     */
    static std::shared_ptr<LookupTableParams<T>> getExp2();
    static std::shared_ptr<LookupTableParams<T>> getDb2Gain();

    /**
     * tanh, unscaled, from -5 to 5
     */
    static std::shared_ptr<LookupTableParams<T>> getTanh5();

private:
    /**
     * Cache uses weak pointers. This allows the cached objects to be
     * freed when the last client reference goes away.
     */
    static std::weak_ptr<LookupTableParams<T>> bipolarAudioTaper;
    static std::weak_ptr<LookupTableParams<T>> sinLookupTable;
    static std::weak_ptr<LookupTableParams<T>> exp2;
    static std::weak_ptr<LookupTableParams<T>> db2Gain;
    static std::weak_ptr<LookupTableParams<T>> tanh5;
};