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looper/engine/src/looper.c

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// cppcheck-suppress missingIncludeSystem
#include "looper.h"
#include "channel.h"
#include "command.h"
#include "midi.h"
#include "queue.h"
#include <fcntl.h>
#include <jack/jack.h>
#include <jack/midiport.h>
#include <math.h>
#include <stdatomic.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/stat.h>
#include <unistd.h>
#define STATUS_FIFO "/tmp/looper_status"
static void looper_write_status(void) {
int fd = open(STATUS_FIFO, O_WRONLY | O_NONBLOCK);
if (fd < 0)
return;
struct channel_t *cur = get_channels_array();
int cap = atomic_load(&channel_capacity);
char buf[256];
for (int ch = 0; ch < cap; ch++) {
if (!atomic_load(&cur[ch].active))
continue;
int sc_idx = atomic_load(&cur[ch].current_scene);
int state = atomic_load(&cur[ch].scenes[sc_idx].state);
const char *state_str;
switch (state) {
case STATE_IDLE:
state_str = "IDLE";
break;
case STATE_RECORD:
state_str = "RECORD";
break;
case STATE_LOOPING:
state_str = "LOOPING";
break;
case STATE_PAUSED:
state_str = "PAUSED";
break;
default:
state_str = "UNKNOWN";
}
int n = snprintf(buf, sizeof(buf), "CH=%d SC=%d STATE=%s\n", ch, sc_idx,
state_str);
if (n > 0) {
int ret = write(fd, buf, n);
(void)ret;
}
}
close(fd);
}
/* Global state (shared across files) */
struct channel_t *_Atomic channels = NULL;
atomic_int channel_capacity = 0;
atomic_int channel_count = 0;
int next_channel_id = 1;
spsc_queue_t cmd_queue_main_midi;
spsc_queue_t cmd_queue_main_fifo;
atomic_int global_rt_cycles = 0;
jack_port_t *midi_control_port = NULL;
jack_port_t *midi_clock_port = NULL;
atomic_int control_key_active = 0;
atomic_int bind_channel = 0;
spsc_queue_t cmd_queue;
/* Deferred removal index and cycle counter */
static int pending_unregister_idx = -1;
static int pending_unregister_cycle = 0;
/* Deferred free of old channel array (must not free while RT thread may hold
* pointer) */
static struct channel_t *pending_old = NULL;
static int pending_old_cycle = 0;
/* Helper: grow the channel array so that index idx is valid */
static int ensure_capacity(jack_client_t *client, int idx) {
(void)client;
int cur_cap = atomic_load(&channel_capacity);
if (idx < cur_cap)
return 0;
int new_cap = cur_cap == 0 ? 8 : cur_cap;
while (new_cap <= idx)
new_cap *= 2;
struct channel_t *new_arr = calloc(new_cap, sizeof(struct channel_t));
if (!new_arr)
return -1;
/* copy existing channels */
if (cur_cap > 0)
memcpy(new_arr, atomic_load(&channels), cur_cap * sizeof(struct channel_t));
/* atomically publish new array, defer free of old */
struct channel_t *old = atomic_exchange(&channels, new_arr);
atomic_store(&channel_capacity, new_cap);
/* schedule old pointer for later deallocation (after RT cycle) */
pending_old = old;
pending_old_cycle = atomic_load(&global_rt_cycles);
return 0;
}
static void apply_command(command_t cmd) {
int cap = atomic_load(&channel_capacity);
struct channel_t *cur = get_channels_array();
switch (cmd.type) {
case CMD_CYCLE:
if (cmd.channel >= 0 && cmd.channel < cap) {
int sc_idx = atomic_load(&cur[cmd.channel].current_scene);
scene_t *sc = &cur[cmd.channel].scenes[sc_idx];
int cst = atomic_load(&sc->state);
int next;
switch (cst) {
case STATE_IDLE:
next = STATE_RECORD;
break;
case STATE_RECORD:
next = STATE_LOOPING;
break;
case STATE_LOOPING:
next = STATE_PAUSED;
break;
case STATE_PAUSED:
next = STATE_LOOPING;
break;
default:
next = STATE_IDLE;
break;
}
atomic_store(&sc->state, next);
}
break;
case CMD_STOP:
if (cmd.channel >= 0 && cmd.channel < cap) {
struct channel_t *ch = &cur[cmd.channel];
int sc_cnt = atomic_load(&ch->scene_count);
for (int s = 0; s < sc_cnt; s++) {
atomic_store(&ch->scenes[s].state, STATE_IDLE);
atomic_store(&ch->scenes[s].loop_count, 0);
atomic_store(&ch->scenes[s].record_pos, 0);
atomic_store(&ch->scenes[s].playback_pos, 0);
atomic_store(&ch->scenes[s].prev_state, -1);
}
} else {
for (int i = 0; i < cap; i++) {
struct channel_t *ch = &cur[i];
int sc_cnt = atomic_load(&ch->scene_count);
for (int s = 0; s < sc_cnt; s++) {
atomic_store(&ch->scenes[s].state, STATE_IDLE);
atomic_store(&ch->scenes[s].loop_count, 0);
atomic_store(&ch->scenes[s].record_pos, 0);
atomic_store(&ch->scenes[s].playback_pos, 0);
atomic_store(&ch->scenes[s].prev_state, -1);
}
}
}
break;
case CMD_BIND_CHANNEL:
atomic_store(&bind_channel, cmd.data);
break;
case CMD_UNBIND:
atomic_store(&bind_channel, 0);
break;
default:
break;
}
}
/* ----------------------------------------------------------------
* process callback
* ---------------------------------------------------------------- */
int process_callback(jack_nframes_t nframes, void *arg) {
(void)arg;
if (midi_control_port) {
void *midi_ctrl_buf = jack_port_get_buffer(midi_control_port, nframes);
if (midi_ctrl_buf) {
midi_handle_events(midi_ctrl_buf, nframes);
}
}
/* drain RTsafe commands */
command_t cmd;
while (queue_pop(&cmd_queue, &cmd)) {
apply_command(cmd);
}
/* process each active channel */
struct channel_t *active_channels = get_channels_array();
int cap = atomic_load(&channel_capacity);
for (int c = 0; c < cap; c++) {
if (!atomic_load(&active_channels[c].active))
continue;
/* Guard against NULL ports (e.g. if port registration failed) */
if (active_channels[c].type == CHANNEL_AUDIO) {
if (!active_channels[c].audio_in || !active_channels[c].audio_out) {
fprintf(stderr, "WARN: channel %d has NULL audio port(s), skipping\n",
c);
continue;
}
} else {
/* CHANNEL_MIDI */
if (!active_channels[c].midi_in || !active_channels[c].midi_out) {
fprintf(stderr, "WARN: channel %d has NULL MIDI port(s), skipping\n",
c);
continue;
}
}
/* Obtain current scene pointer */
int sc_idx = atomic_load(&active_channels[c].current_scene);
scene_t *sc = &active_channels[c].scenes[sc_idx];
const jack_default_audio_sample_t *in =
(const jack_default_audio_sample_t *)jack_port_get_buffer(
active_channels[c].audio_in, nframes);
jack_default_audio_sample_t *out =
(jack_default_audio_sample_t *)jack_port_get_buffer(
active_channels[c].audio_out, nframes);
if (!out)
continue;
int state = atomic_load(&sc->state);
int prev_state = atomic_load(&sc->prev_state);
if (state != prev_state) {
switch (state) {
case STATE_RECORD:
atomic_store(&sc->record_pos, 0);
atomic_store(&sc->loop_count, 0);
break;
case STATE_LOOPING:
if (atomic_load(&sc->record_pos) > 0)
atomic_store(&sc->loop_count, atomic_load(&sc->record_pos));
atomic_store(&sc->playback_pos, 0);
break;
default:
break;
}
}
if (active_channels[c].type == CHANNEL_MIDI) {
/* MIDI channel handling */
switch (state) {
case STATE_RECORD: {
void *midi_in_buf =
jack_port_get_buffer(active_channels[c].midi_in, nframes);
if (midi_in_buf) {
jack_nframes_t nevents = jack_midi_get_event_count(midi_in_buf);
jack_midi_event_t ev;
for (jack_nframes_t j = 0; j < nevents; j++) {
if (jack_midi_event_get(&ev, midi_in_buf, j) != 0)
continue;
int rp = atomic_load(&sc->record_pos);
if (rp < MAX_MIDI_EVENTS) {
sc->loop.midi_events[rp].timestamp = ev.time;
sc->loop.midi_events[rp].status = ev.buffer[0];
sc->loop.midi_events[rp].note = (ev.size > 1) ? ev.buffer[1] : 0;
sc->loop.midi_events[rp].velocity =
(ev.size > 2) ? ev.buffer[2] : 0;
atomic_store(&sc->record_pos, rp + 1);
}
}
/* forward incoming MIDI to output during record */
void *midi_out_buf =
jack_port_get_buffer(active_channels[c].midi_out, nframes);
if (midi_out_buf) {
jack_midi_clear_buffer(midi_out_buf);
for (jack_nframes_t j = 0; j < nevents; j++) {
if (jack_midi_event_get(&ev, midi_in_buf, j) != 0)
continue;
jack_midi_event_write(midi_out_buf, ev.time, ev.buffer, ev.size);
}
}
}
break;
}
case STATE_LOOPING: {
void *midi_out_buf =
jack_port_get_buffer(active_channels[c].midi_out, nframes);
if (midi_out_buf) {
jack_midi_clear_buffer(midi_out_buf);
int cnt = atomic_load(&sc->loop_count);
if (cnt > 0) {
for (int e = 0; e < cnt; e++) {
unsigned char msg[3];
msg[0] = sc->loop.midi_events[e].status;
msg[1] = sc->loop.midi_events[e].note;
msg[2] = sc->loop.midi_events[e].velocity;
jack_midi_event_write(midi_out_buf, 0, msg, 3);
}
}
}
break;
}
case STATE_PAUSED:
/* no output */
break;
default: /* IDLE */
{
void *midi_in_buf =
jack_port_get_buffer(active_channels[c].midi_in, nframes);
void *midi_out_buf =
jack_port_get_buffer(active_channels[c].midi_out, nframes);
if (midi_in_buf && midi_out_buf) {
jack_midi_clear_buffer(midi_out_buf);
jack_nframes_t nevents = jack_midi_get_event_count(midi_in_buf);
jack_midi_event_t ev;
for (jack_nframes_t j = 0; j < nevents; j++) {
if (jack_midi_event_get(&ev, midi_in_buf, j) != 0)
continue;
jack_midi_event_write(midi_out_buf, ev.time, ev.buffer, ev.size);
}
}
} break;
}
if (state == STATE_LOOPING) {
atomic_store(&sc->loop_count, atomic_load(&sc->record_pos));
}
} else {
/* audio channel handling */
jack_nframes_t i;
switch (state) {
case STATE_RECORD:
if (in) {
float *f_out = (float *)out;
const float *f_in = (const float *)in;
for (i = 0; i < nframes; i++) {
int rp = atomic_load(&sc->record_pos);
if (rp < LOOP_BUF_SIZE) {
sc->loop.audio_buffer[rp] = f_in[i];
atomic_store(&sc->record_pos, rp + 1);
}
f_out[i] = f_in[i];
}
} else {
memset(out, 0, sizeof(jack_default_audio_sample_t) * nframes);
}
break;
case STATE_LOOPING: {
int loop_cnt = atomic_load(&sc->loop_count);
if (loop_cnt > 0) {
float *outf = (float *)out;
int pp = atomic_load(&sc->playback_pos);
for (i = 0; i < nframes; i++) {
outf[i] = sc->loop.audio_buffer[pp];
pp = (pp + 1) % loop_cnt;
}
atomic_store(&sc->playback_pos, pp);
} else {
memset(out, 0, sizeof(jack_default_audio_sample_t) * nframes);
}
break;
}
case STATE_PAUSED:
memset(out, 0, sizeof(jack_default_audio_sample_t) * nframes);
break;
default: /* IDLE */
if (in) {
memcpy(out, in, sizeof(jack_default_audio_sample_t) * nframes);
} else {
memset(out, 0, sizeof(jack_default_audio_sample_t) * nframes);
}
break;
}
}
atomic_store(&sc->prev_state, state);
}
/* MIDI clock events affect channel 0 only */
if (midi_clock_port) {
void *midi_clock_buf = jack_port_get_buffer(midi_clock_port, nframes);
if (midi_clock_buf) {
jack_nframes_t n_clock_events = jack_midi_get_event_count(midi_clock_buf);
jack_midi_event_t cev;
for (jack_nframes_t j = 0; j < n_clock_events; j++) {
if (jack_midi_event_get(&cev, midi_clock_buf, j) != 0)
continue;
if (cev.size >= 1) {
unsigned char msg = cev.buffer[0];
switch (msg) {
case 0xFA: {
struct channel_t *cur = atomic_load(&channels);
int sc_idx = atomic_load(&cur[0].current_scene);
int s = atomic_load(&cur[0].scenes[sc_idx].state);
if (s == STATE_IDLE)
atomic_store(&cur[0].scenes[sc_idx].state, STATE_RECORD);
break;
}
case 0xFC: {
struct channel_t *cur = atomic_load(&channels);
int sc_idx = atomic_load(&cur[0].current_scene);
atomic_store(&cur[0].scenes[sc_idx].state, STATE_IDLE);
break;
}
case 0xFB: {
struct channel_t *cur = atomic_load(&channels);
int sc_idx = atomic_load(&cur[0].current_scene);
int s = atomic_load(&cur[0].scenes[sc_idx].state);
if (s == STATE_PAUSED)
atomic_store(&cur[0].scenes[sc_idx].state, STATE_LOOPING);
break;
}
default:
break;
}
}
}
}
}
atomic_fetch_add_explicit(&global_rt_cycles, 1, memory_order_release);
return 0;
}
/* ----------------------------------------------------------------
* shutdown callback
* ---------------------------------------------------------------- */
void jack_shutdown_cb(void *arg) {
(void)arg;
fprintf(stderr, "JACK shutdown\n");
exit(0);
}
/* ----------------------------------------------------------------
* looper initialisation
* ---------------------------------------------------------------- */
int looper_init(jack_client_t *client) {
/* create status FIFO (ignore if already exists) */
mkfifo(STATUS_FIFO, 0666);
queue_init(&cmd_queue);
queue_init(&cmd_queue_main_midi);
queue_init(&cmd_queue_main_fifo);
/* allocate initial array for at least one channel */
if (ensure_capacity(client, 0) != 0) {
fprintf(stderr, "Cannot allocate channel array\n");
return -1;
}
struct channel_t *init = atomic_load(&channels);
/* channel 0 */
atomic_store(&init[0].active, 1);
atomic_store(&init[0].scene_count, 1);
atomic_store(&init[0].current_scene, 0);
atomic_store(&init[0].scenes[0].loop_count, 0);
atomic_store(&init[0].scenes[0].record_pos, 0);
atomic_store(&init[0].scenes[0].playback_pos, 0);
atomic_store(&init[0].scenes[0].state, STATE_IDLE);
atomic_store(&init[0].scenes[0].prev_state, -1);
init[0].audio_in = jack_port_register(
client, "input", JACK_DEFAULT_AUDIO_TYPE, JackPortIsInput, 0);
init[0].audio_out = jack_port_register(
client, "output", JACK_DEFAULT_AUDIO_TYPE, JackPortIsOutput, 0);
if (!init[0].audio_in || !init[0].audio_out) {
fprintf(stderr, "Could not create audio ports for channel 0\n");
return -1;
}
atomic_store(&channel_count, 1);
midi_control_port = jack_port_register(
client, "control", JACK_DEFAULT_MIDI_TYPE, JackPortIsInput, 0);
midi_clock_port = jack_port_register(client, "clock", JACK_DEFAULT_MIDI_TYPE,
JackPortIsInput, 0);
if (!midi_control_port || !midi_clock_port) {
fprintf(stderr, "Could not create MIDI ports\n");
return -1;
}
return 0;
}
/* ----------------------------------------------------------------
* mainloop command processing
* ---------------------------------------------------------------- */
void looper_process_commands(jack_client_t *client) {
/* Drain mainloop command queues (add/remove) */
command_t cmd;
while (queue_pop(&cmd_queue_main_midi, &cmd)) {
switch (cmd.type) {
case CMD_ADD_CHANNEL: {
int cap = atomic_load(&channel_capacity);
int idx;
for (idx = 0; idx < cap; idx++)
if (!atomic_load(&(get_channels_array()[idx].active)))
break;
if (idx == cap) {
if (ensure_capacity(client, idx) != 0)
break;
}
channel_add(client, idx);
break;
}
case CMD_ADD_MIDI_CHANNEL: {
int cap = atomic_load(&channel_capacity);
int idx;
for (idx = 0; idx < cap; idx++)
if (!atomic_load(&(get_channels_array()[idx].active)))
break;
if (idx == cap) {
if (ensure_capacity(client, idx) != 0)
break;
}
channel_add_midi(client, idx);
break;
}
case CMD_REMOVE_CHANNEL: {
int cap = atomic_load(&channel_capacity);
int remove_idx = -1;
for (int idx = 1; idx < cap; idx++)
if (atomic_load(&(get_channels_array()[idx].active)))
remove_idx = idx;
if (remove_idx != -1) {
channel_remove(client, remove_idx);
pending_unregister_idx = remove_idx;
pending_unregister_cycle = atomic_load(&global_rt_cycles);
}
break;
}
case CMD_ADD_SCENE: {
int cap = atomic_load(&channel_capacity);
int bind = atomic_load(&bind_channel);
int ch = bind;
if (ch < cap) {
channel_add_scene(client, ch);
}
break;
}
case CMD_REMOVE_SCENE: {
int cap = atomic_load(&channel_capacity);
int bind = atomic_load(&bind_channel);
int ch = bind;
if (ch < cap) {
channel_remove_scene(client, ch);
}
break;
}
case CMD_NEXT_SCENE: {
int cap = atomic_load(&channel_capacity);
int bind = atomic_load(&bind_channel);
int ch = bind;
if (ch < cap) {
channel_next_scene(client, ch);
}
break;
}
case CMD_PREV_SCENE: {
int cap = atomic_load(&channel_capacity);
int bind = atomic_load(&bind_channel);
int ch = bind;
if (ch < cap) {
channel_prev_scene(client, ch);
}
break;
}
default:
break;
}
}
while (queue_pop(&cmd_queue_main_fifo, &cmd)) {
switch (cmd.type) {
case CMD_ADD_CHANNEL: {
int cap = atomic_load(&channel_capacity);
int idx;
for (idx = 0; idx < cap; idx++)
if (!atomic_load(&(get_channels_array()[idx].active)))
break;
if (idx == cap) {
if (ensure_capacity(client, idx) != 0)
break;
}
channel_add(client, idx);
break;
}
case CMD_ADD_MIDI_CHANNEL: {
int cap = atomic_load(&channel_capacity);
int idx;
for (idx = 0; idx < cap; idx++)
if (!atomic_load(&(get_channels_array()[idx].active)))
break;
if (idx == cap) {
if (ensure_capacity(client, idx) != 0)
break;
}
channel_add_midi(client, idx);
break;
}
case CMD_REMOVE_CHANNEL: {
int cap = atomic_load(&channel_capacity);
int remove_idx = -1;
for (int idx = 1; idx < cap; idx++)
if (atomic_load(&(get_channels_array()[idx].active)))
remove_idx = idx;
if (remove_idx != -1) {
channel_remove(client, remove_idx);
pending_unregister_idx = remove_idx;
pending_unregister_cycle = atomic_load(&global_rt_cycles);
}
break;
}
case CMD_ADD_SCENE: {
int cap = atomic_load(&channel_capacity);
int bind = atomic_load(&bind_channel);
int ch = bind;
if (ch < cap) {
channel_add_scene(client, ch);
}
break;
}
case CMD_REMOVE_SCENE: {
int cap = atomic_load(&channel_capacity);
int bind = atomic_load(&bind_channel);
int ch = bind;
if (ch < cap) {
channel_remove_scene(client, ch);
}
break;
}
case CMD_NEXT_SCENE: {
int cap = atomic_load(&channel_capacity);
int bind = atomic_load(&bind_channel);
int ch = bind;
if (ch < cap) {
channel_next_scene(client, ch);
}
break;
}
case CMD_PREV_SCENE: {
int cap = atomic_load(&channel_capacity);
int bind = atomic_load(&bind_channel);
int ch = bind;
if (ch < cap) {
channel_prev_scene(client, ch);
}
break;
}
default:
break;
}
}
/* Deferred port unregistration wait until RT thread has seen active=0 */
if (pending_unregister_idx != -1) {
int current_cycle = atomic_load(&global_rt_cycles);
if (current_cycle - pending_unregister_cycle >= 1) {
int idx = pending_unregister_idx;
struct channel_t *cur = atomic_load(&channels);
if (cur[idx].audio_in)
jack_port_unregister(client, cur[idx].audio_in);
if (cur[idx].audio_out)
jack_port_unregister(client, cur[idx].audio_out);
if (cur[idx].midi_in)
jack_port_unregister(client, cur[idx].midi_in);
if (cur[idx].midi_out)
jack_port_unregister(client, cur[idx].midi_out);
pending_unregister_idx = -1;
}
}
/* Deferred free of old channel array wait until RT thread has seen new
* pointer */
if (pending_old != NULL) {
int current_cycle = atomic_load(&global_rt_cycles);
if (current_cycle - pending_old_cycle >= 1) {
free(pending_old);
pending_old = NULL;
}
}
/* write current state to status FIFO */
looper_write_status();
}