NullMixer.hpp

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#pragma once

#include <mixer/Mixer/Mixer.hpp>

/**
 * Null mixer; returns zero.
 *
 * Used as a placeholder for output channels that are unassigned in groups.
 */
class NullMixer : public Mixer
{
public:
    NullMixer() : Mixer(nullptr, 0) {}
    virtual ~NullMixer() = default;

    // no copy, assignment, move, move assignment
    NullMixer(const NullMixer &) = delete;
    NullMixer &operator=(const NullMixer &) = delete;
    NullMixer(NullMixer &&) = delete;
    NullMixer &operator=(NullMixer &&) = delete;

    /**
     * Factory method.
     *
     * Given a pointer to a buffer containing a text description of the mixer,
     * returns a pointer to a new instance of the mixer.
     *
     * @param buf           Buffer containing a text description of
     *              the mixer.
     * @param buflen        Length of the buffer in bytes, adjusted
     *              to reflect the bytes consumed.
     * @return          A new NullMixer instance, or nullptr
     *              if the text format is bad.
     */
    static NullMixer        *from_text(const char *buf, unsigned &buflen);

    unsigned            mix(float *outputs, unsigned space) override;

    unsigned            set_trim(float trim) override { return 1; }
    unsigned            get_trim(float *trim) override { return 1; }

};