/*
  An LV2 plugin to calculate the difference of two signals.
  Copyright 2011 David Robillard
  Copyright 2004 Mike Rawes

  This is free software: you can redistribute it and/or modify it
  under the terms of the GNU General Public License as published by
  the Free Software Foundation, either version 3 of the License, or
  (at your option) any later version.

  This software is distributed in the hope that it will be useful,
  but WITHOUT ANY WARRANTY; without even the implied warranty of
  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  GNU General Public License for more details.

  You should have received a copy of the GNU General Public License
  along with this software.  If not, see <http://www.gnu.org/licenses/>.
*/

#include <stdlib.h>
#include "lv2/lv2plug.in/ns/lv2core/lv2.h"

#define DIFFERENCE_INPUT  0
#define DIFFERENCE_MINUS  1
#define DIFFERENCE_OUTPUT 2

typedef struct {
	float* input;
	float* minus;
	float* output;
} Difference;

static void
cleanup(LV2_Handle instance)
{
	free(instance);
}

static void
connect_port(LV2_Handle instance,
             uint32_t   port,
             void*     data)
{
	Difference* plugin = (Difference*)instance;

	switch (port) {
	case DIFFERENCE_INPUT:
		plugin->input = data;
		break;
	case DIFFERENCE_MINUS:
		plugin->minus = data;
		break;
	case DIFFERENCE_OUTPUT:
		plugin->output = data;
		break;
	}
}

static LV2_Handle
instantiate(const LV2_Descriptor*     descriptor,
            double                    sample_rate,
            const char*               bundle_path,
            const LV2_Feature* const* features)
{
	Difference* plugin = (Difference*)malloc(sizeof(Difference));

	return (LV2_Handle)plugin;
}

static void
runDifference_iama_oa(LV2_Handle instance,
                      uint32_t   sample_count)
{
	Difference* plugin = (Difference*)instance;

	/* Input (array of floats of length sample_count) */
	const float* input = plugin->input;

	/* Input to Subtract (array of floats of length sample_count) */
	const float* minus = plugin->minus;

	/* Output (array of floats of length sample_count) */
	float* output = plugin->output;

	for (uint32_t s = 0; s < sample_count; ++s) {
		output[s] = input[s] - minus[s];
	}
}

static void
runDifference_iamc_oa(LV2_Handle instance,
                      uint32_t   sample_count)
{
	Difference* plugin = (Difference*)instance;

	/* Input (array of floats of length sample_count) */
	const float* input = plugin->input;

	/* Input to Subtract (float value) */
	const float minus = *(plugin->minus);

	/* Output (array of floats of length sample_count) */
	float* output = plugin->output;

	for (uint32_t s = 0; s < sample_count; ++s) {
		output[s] = input[s] - minus;
	}
}

static void
runDifference_icma_oa(LV2_Handle instance,
                      uint32_t   sample_count)
{
	Difference* plugin = (Difference*)instance;

	/* Input (float value) */
	const float input = *(plugin->input);

	/* Input to Subtract (array of floats of length sample_count) */
	const float* minus = plugin->minus;

	/* Output (array of floats of length sample_count) */
	float* output = plugin->output;

	for (uint32_t s = 0; s < sample_count; ++s) {
		output[s] = input - minus[s];
	}
}

static void
runDifference_icmc_oc(LV2_Handle instance,
                      uint32_t   sample_count)
{
	Difference* plugin = (Difference*)instance;

	/* Input (float value) */
	const float input = *(plugin->input);

	/* Input to Subtract (float value) */
	const float minus = *(plugin->minus);

	/* Output Frequency (pointer to float value) */
	float* output = plugin->output;

	output[0] = input - minus;
}

static const LV2_Descriptor descriptor = {
	"http://drobilla.net/plugins/blip/difference",
	instantiate,
	connect_port,
	NULL,
	runDifference_icmc_oc,
	NULL,
	cleanup,
	NULL,
};

LV2_SYMBOL_EXPORT const LV2_Descriptor*
lv2_descriptor(uint32_t index)
{
	switch (index) {
	case 0:  return &descriptor;
	default: return NULL;
	}
}