mem in lv2

templates/lv2/src/lv2.c

@@ -23,6 +23,7 @@ typedef struct {
 #if DATA_PRODUCT_CONTROL_INPUTS_N > 0
 	float		params[DATA_PRODUCT_CONTROL_INPUTS_N];
 #endif
+	void *		mem;
 } plugin_instance;
 
 static LV2_Handle instantiate(const struct LV2_Descriptor * descriptor, double sample_rate, const char * bundle_path, const LV2_Feature * const * features) {
@@ -31,6 +32,16 @@ static LV2_Handle instantiate(const struct LV2_Descriptor * descriptor, double s
 		return NULL;
 	plugin_init(&instance->p);
 	plugin_set_sample_rate(&instance->p, sample_rate);
+	size_t req = plugin_mem_req(&instance->p);
+	if (req != 0) {
+		instance->mem = malloc(req);
+		if (instance->mem == NULL) {
+			plugin_fini(&instance->p);
+			return NULL;
+		}
+		plugin_mem_set(&instance->p, instance->mem);
+	} else
+		instance->mem = NULL;
 #if DATA_PRODUCT_AUDIO_INPUT_CHANNELS_N > 0
 	for (uint32_t i = 0; i < DATA_PRODUCT_AUDIO_INPUT_CHANNELS_N; i++)
 		instance->x[i] = NULL;
@@ -142,6 +153,8 @@ static void run(LV2_Handle instance, uint32_t sample_count) {
 static void cleanup(LV2_Handle instance) {
 	plugin_instance * i = (plugin_instance *)instance;
 	plugin_fini(&i->p);
+	if (i->mem)
+		free(i->mem);
 	free(instance);
 }
 

test/plugin.h

@@ -1,8 +1,16 @@
+#include <string.h>
 #include <math.h>
 
 typedef struct plugin {
 	float	gain;
 	char	bypass;
+	size_t	delay;
+
+	float	sample_rate;
+	size_t	delay_line_length;
+
+	float *	delay_line;
+	size_t	delay_line_cur;
 } plugin;
 
 static void plugin_init(plugin *instance) {
@@ -14,9 +22,21 @@ static void plugin_fini(plugin *instance) {
 }
 
 static void plugin_set_sample_rate(plugin *instance, float sample_rate) {
+	instance->sample_rate = sample_rate;
+	instance->delay_line_length = ceilf(sample_rate) + 1;
+}
+
+static size_t plugin_mem_req(plugin *instance) {
+	return instance->delay_line_length * sizeof(float);
+}
+
+static void plugin_mem_set(plugin *instance, void *mem) {
+	instance->delay_line = mem;
 }
 
 static void plugin_reset(plugin *instance) {
+	memset(instance->delay_line, 0, instance->delay_line_length * sizeof(float));
+	instance->delay_line_cur = 0;
 }
 
 static void plugin_set_parameter(plugin *instance, size_t index, float value) {
@@ -25,6 +45,9 @@ static void plugin_set_parameter(plugin *instance, size_t index, float value) {
 		instance->gain = value;
 		break;
 	case 1:
+		instance->delay = roundf(instance->sample_rate * 0.001f * value);
+		break;
+	case 2:
 		instance->bypass = value >= 0.5f;
 		break;
 	}
@@ -35,8 +58,18 @@ static float plugin_get_parameter(plugin *instance, size_t index) {
 	return 0.f;
 }
 
-static void plugin_process(plugin *instance, const float **inputs, float **outputs, size_t n_samples) {
-	const float g = instance->bypass ? 1.f : powf(10.f, 0.05f * instance->gain);
-	for (size_t i = 0; i < n_samples; i++)
-		outputs[0][i] = g * inputs[0][i];
+static size_t calc_index(size_t cur, size_t delay, size_t len) {
+	return (cur < delay ? cur + len : cur) - delay;
+}
+
+static void plugin_process(plugin *instance, const float **inputs, float **outputs, size_t n_samples) {
+	const float g = powf(10.f, 0.05f * instance->gain);
+	for (size_t i = 0; i < n_samples; i++) {
+		instance->delay_line[instance->delay_line_cur] = inputs[0][i];
+		const float y = g * instance->delay_line[calc_index(instance->delay_line_cur, instance->delay, instance->delay_line_length)];
+		instance->delay_line_cur++;
+		if (instance->delay_line_cur == instance->delay_line_length)
+			instance->delay_line_cur = 0;
+		outputs[0][i] = instance->bypass ? inputs[0][i] : y;
+	}
 }

test/product.json

@@ -48,6 +48,22 @@
 				"unit": "db",
 				"map": "linear"
 			},
+			{
+				"name": "Delay",
+				"shortName": "Delay",
+				"direction": "input",
+				"isBypass": false,
+				"isLatency": false,
+				"defaultValue": 0.0,
+				"minimum": 0.0,
+				"maximum": 1000.0,
+				"toggled": false,
+				"optional": false,
+				"integer": false,
+				"list": false,
+				"unit": "ms",
+				"map": "linear"
+			},
 			{
 				"name": "Bypass",
 				"shortName": "Bypass",