myAmp.c

/* include libs */
#include "stddef.h"
#include "stdint.h"
#include "stdlib.h"
//#include "math.h"
#include "lv2.h"

/* class definition */
typedef struct
{
	float* audio_in_ptr;
	float* audio_out_ptr;
	float* amp_ptr;
} MyAmp;


/* internal core methods */
static LV2_Handle instantiate (const struct LV2_Descriptor *descriptor, double sample_rate, const char *bundle_path, const LV2_Feature *const *features)
{
	MyAmp* m = (MyAmp*) calloc (1, sizeof (MyAmp));	
	return m;
}
static void connect_port (LV2_Handle instance, uint32_t port, void *data_location)
{
	MyAmp* m = (MyAmp*) instance;
	if (!m) return;

	switch (port)
	{
		case 0:
			m->audio_in_ptr = (float*) data_location;
			break;

		case 1:
			m->audio_out_ptr = (float*) data_location;
			break;
			
		case 2:
			m->amp_ptr = (float*) data_location;
			break;

		default:
			break;
	}
}

static void activate (LV2_Handle instance)
{
	/* not needed here */
}

static void run (LV2_Handle instance, uint32_t sample_count)
{
	MyAmp* m = (MyAmp*) instance;
	if (!m) return;
	if ((!m->audio_in_ptr) || (!m->audio_out_ptr) || (!m->amp_ptr)) return;
	
	for (uint32_t i = 0; i <sample_count; ++i)
	{
		m->audio_out_ptr[i] = m->audio_in_ptr[i] * *(m->amp_ptr);
	}
}

static void deactivate (LV2_Handle instance)
{
	/* not needed here */
}

static void cleanup (LV2_Handle instance)
{
	MyAmp* m = (MyAmp*) instance;
	if (!m) return;
	free (m);
}

static const void * extension_data (const char *uri)
{
	return NULL;
}


/* descriptor */
static LV2_Descriptor const descriptor = 
{
	"https://github.com/Inqb8tr-jp/myAmp",
	instantiate,
	connect_port,
	activate /* or NULL */,
	run,
	deactivate /* or NULL */,
	cleanup,
	extension_data /* or NULL */
};


/* interface */
const LV2_SYMBOL_EXPORT LV2_Descriptor* lv2_descriptor (uint32_t index)
{
	if (index == 0) return &descriptor;
	else return NULL;
}