AudioEffectGain_F32.h

/*
 * AudioEffectGain_F32
 * 
 * Created: Chip Audette, November 2016
 * Purpose; Apply digital gain to the audio data.  Assumes floating-point data.
 *          
 * This processes a single stream fo audio data (ie, it is mono)       
 *          
 * MIT License.  use at your own risk.
*/

#ifndef _AudioEffectGain_F32_h
#define _AudioEffectGain_F32_h

#include <arm_math.h> //ARM DSP extensions.  for speed!
#include <AudioStream_F32.h>

class AudioEffectGain_F32 : public AudioStream_F32
{
  //GUI: inputs:1, outputs:1  //this line used for automatic generation of GUI node  
  public:
    //constructor
    AudioEffectGain_F32(void) : AudioStream_F32(1, inputQueueArray_f32) {};
	AudioEffectGain_F32(const AudioSettings_F32 &settings) : AudioStream_F32(1, inputQueueArray_f32) {};

    //here's the method that does all the work
    void update(void) {
		//Serial.println("AudioEffectGain_F32: updating.");  //for debugging.
		audio_block_f32_t *block;
		block = AudioStream_F32::receiveWritable_f32();
		if (!block) return;

		//apply the gain
		//for (int i = 0; i < AUDIO_BLOCK_SAMPLES; i++) block->data[i] = gain * (block->data[i]); //non DSP way to do it
		arm_scale_f32(block->data, gain, block->data, block->length); //use ARM DSP for speed!

		//transmit the block and be done
		AudioStream_F32::transmit(block);
		AudioStream_F32::release(block);
    }

    //methods to set parameters of this module
    void setGain(float g) { gain = g; }
    void setGain_dB(float gain_dB) {
      float gain = pow(10.0, gain_dB / 20.0);
      setGain(gain);
    }

    //methods to return information about this module
    float getGain(void) { return gain; }
    float getGain_dB(void) { return 20.0*log10(gain); }
    
  private:
    audio_block_f32_t *inputQueueArray_f32[1]; //memory pointer for the input to this module
    float gain = 1.0; //default value
};

#endif