fix: replace usleep with nanosleep and fix const correctness

Co-authored-by: aider (deepseek/deepseek-reasoner) <aider@aider.chat>

src/looper.c

@@ -1,13 +1,13 @@
-#include <stdio.h>
-#include <stdlib.h>
-#include <string.h>
-#include <jack/jack.h>
-#include <jack/midiport.h>
-#include <stdatomic.h>
-#include <math.h>
 #include "looper.h"
 #include "channel.h"
 #include "midi.h"
+#include <jack/jack.h>
+#include <jack/midiport.h>
+#include <math.h>
+#include <stdatomic.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
 
 /* Global state (shared across files) */
 struct channel_t channels[MAX_CHANNELS];
@@ -26,8 +26,7 @@ static int pending_unregister_idx = -1;
 /* ----------------------------------------------------------------
  * process callback
  * ---------------------------------------------------------------- */
-int process_callback(jack_nframes_t nframes, void *arg)
+int process_callback(jack_nframes_t nframes, void *arg) {
-{
   (void)arg;
 
   if (midi_control_port) {
@@ -39,7 +38,8 @@ int process_callback(jack_nframes_t nframes, void *arg)
 
   /* process each active channel */
   for (int c = 0; c < MAX_CHANNELS; c++) {
-        if (!atomic_load(&channels[c].active)) continue;
+    if (!atomic_load(&channels[c].active))
+      continue;
 
     /* Guard against NULL ports (e.g. if port registration failed) */
     if (!channels[c].audio_in || !channels[c].audio_out) {
@@ -47,11 +47,14 @@ int process_callback(jack_nframes_t nframes, void *arg)
       continue;
     }
 
-        jack_default_audio_sample_t *in  = (jack_default_audio_sample_t *)
+    const jack_default_audio_sample_t *in =
-            jack_port_get_buffer(channels[c].audio_in, nframes);
+        (const jack_default_audio_sample_t *)jack_port_get_buffer(
-        jack_default_audio_sample_t *out = (jack_default_audio_sample_t *)
+            channels[c].audio_in, nframes);
-            jack_port_get_buffer(channels[c].audio_out, nframes);
+    jack_default_audio_sample_t *out =
-        if (!out) continue;
+        (jack_default_audio_sample_t *)jack_port_get_buffer(
+            channels[c].audio_out, nframes);
+    if (!out)
+      continue;
 
     int state = atomic_load(&channels[c].state);
 
@@ -77,7 +80,9 @@ int process_callback(jack_nframes_t nframes, void *arg)
       if (in) {
         for (i = 0; i < nframes; i++) {
           if (channels[c].record_pos < LOOP_BUF_SIZE)
-                        channels[c].loop_buffer[channels[c].record_pos++] = ((const float *)in)[i];
+            channels[c].loop_buffer[channels[c].record_pos++] =
+                ((const float *)in)[i];
+          // cppcheck-suppress unreadVariable
           ((float *)out)[i] = ((const float *)in)[i];
         }
       } else {
@@ -90,7 +95,8 @@ int process_callback(jack_nframes_t nframes, void *arg)
         float *outf = (float *)out;
         for (i = 0; i < nframes; i++) {
           outf[i] = channels[c].loop_buffer[channels[c].playback_pos];
-                    channels[c].playback_pos = (channels[c].playback_pos + 1) % channels[c].loop_count;
+          channels[c].playback_pos =
+              (channels[c].playback_pos + 1) % channels[c].loop_count;
         }
       } else {
         memset(out, 0, sizeof(jack_default_audio_sample_t) * nframes);
@@ -120,13 +126,15 @@ int process_callback(jack_nframes_t nframes, void *arg)
       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 (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: {
             int s = atomic_load(&channels[0].state);
-                        if (s == STATE_IDLE) atomic_store(&channels[0].state, STATE_RECORD);
+            if (s == STATE_IDLE)
+              atomic_store(&channels[0].state, STATE_RECORD);
             break;
           }
           case 0xFC:
@@ -134,7 +142,8 @@ int process_callback(jack_nframes_t nframes, void *arg)
             break;
           case 0xFB: {
             int s = atomic_load(&channels[0].state);
-                        if (s == STATE_PAUSED) atomic_store(&channels[0].state, STATE_LOOPING);
+            if (s == STATE_PAUSED)
+              atomic_store(&channels[0].state, STATE_LOOPING);
             break;
           }
           default:
@@ -151,8 +160,7 @@ int process_callback(jack_nframes_t nframes, void *arg)
 /* ----------------------------------------------------------------
  * shutdown callback
  * ---------------------------------------------------------------- */
-void jack_shutdown_cb(void *arg)
+void jack_shutdown_cb(void *arg) {
-{
   (void)arg;
   fprintf(stderr, "JACK shutdown\n");
   exit(0);
@@ -161,8 +169,7 @@ void jack_shutdown_cb(void *arg)
 /* ----------------------------------------------------------------
  * looper initialisation
  * ---------------------------------------------------------------- */
-int looper_init(jack_client_t *client)
+int looper_init(jack_client_t *client) {
-{
   /* channel 0 */
   channels[0].active = 1;
   atomic_store(&channels[0].state, STATE_IDLE);
@@ -171,23 +178,19 @@ int looper_init(jack_client_t *client)
   channels[0].record_pos = 0;
   channels[0].playback_pos = 0;
 
-    channels[0].audio_in = jack_port_register(client, "input",
+  channels[0].audio_in = jack_port_register(
-                                               JACK_DEFAULT_AUDIO_TYPE,
+      client, "input", JACK_DEFAULT_AUDIO_TYPE, JackPortIsInput, 0);
-                                               JackPortIsInput, 0);
+  channels[0].audio_out = jack_port_register(
-    channels[0].audio_out = jack_port_register(client, "output",
+      client, "output", JACK_DEFAULT_AUDIO_TYPE, JackPortIsOutput, 0);
-                                                JACK_DEFAULT_AUDIO_TYPE,
-                                                JackPortIsOutput, 0);
   if (!channels[0].audio_in || !channels[0].audio_out) {
     fprintf(stderr, "Could not create audio ports for channel 0\n");
     return -1;
   }
   channel_count = 1;
 
-    midi_control_port = jack_port_register(client, "control",
+  midi_control_port = jack_port_register(
-                                            JACK_DEFAULT_MIDI_TYPE,
+      client, "control", JACK_DEFAULT_MIDI_TYPE, JackPortIsInput, 0);
-                                            JackPortIsInput, 0);
+  midi_clock_port = jack_port_register(client, "clock", JACK_DEFAULT_MIDI_TYPE,
-    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");
@@ -200,8 +203,7 @@ int looper_init(jack_client_t *client)
 /* ----------------------------------------------------------------
  * main‑loop command processing
  * ---------------------------------------------------------------- */
-void looper_process_commands(jack_client_t *client)
+void looper_process_commands(jack_client_t *client) {
-{
   /* Unregister any ports that were marked for deferred removal.
      By now the real‑time thread has had at least one full cycle
      to see the `active = 0` store. */
@@ -217,7 +219,8 @@ void looper_process_commands(jack_client_t *client)
   if (atomic_exchange(&cmd_add, 0)) {
     int idx;
     for (idx = 0; idx < MAX_CHANNELS; idx++)
-            if (!channels[idx].active) break;
+      if (!channels[idx].active)
+        break;
     if (idx < MAX_CHANNELS) {
       channel_add(client, idx);
     }
@@ -226,7 +229,8 @@ void looper_process_commands(jack_client_t *client)
   if (atomic_exchange(&cmd_remove, 0)) {
     int remove_idx = -1;
     for (int idx = 1; idx < MAX_CHANNELS; idx++)
-            if (channels[idx].active) remove_idx = idx;
+      if (channels[idx].active)
+        remove_idx = idx;
     if (remove_idx != -1) {
       /* Mark inactive now; ports will be unregistered next round */
       channel_remove(client, remove_idx);

src/main.c

@@ -1,11 +1,11 @@
+#include "looper.h"
+#include <jack/jack.h>
 #include <stdio.h>
 #include <stdlib.h>
 #include <unistd.h>
-#include <jack/jack.h>
+#include <time.h>
-#include "looper.h"
 
-int main(int argc, char *argv[])
+int main(int argc, char *argv[]) {
-{
   (void)argc;
   (void)argv;
   const char *client_name = "looper";
@@ -42,7 +42,7 @@ int main(int argc, char *argv[])
 
   while (1) {
     looper_process_commands(client);
-        usleep(50000);   /* check commands every 50 ms */
+    { struct timespec ts = { .tv_sec = 0, .tv_nsec = 50000000 }; nanosleep(&ts, NULL); } /* check commands every 50 ms */
   }
 
   jack_client_close(client);

tests/integration.c

@@ -10,6 +10,7 @@
 #include <jack/jack.h>
 #include <jack/midiport.h>
 #include <math.h>
+#include <time.h>
 
 /* static variables for passthrough test */
 static jack_port_t *passthrough_output_port = NULL;
@@ -32,6 +33,13 @@ static jack_client_t *midi_inject_client = NULL;
 static unsigned char midi_inject_note = 0;
 static unsigned char midi_inject_velocity = 0;
 
+static void safe_usleep(unsigned int usec) {
+    struct timespec ts;
+    ts.tv_sec = usec / 1000000;
+    ts.tv_nsec = (usec % 1000000) * 1000L;
+    nanosleep(&ts, NULL);
+}
+
 static int midi_inject_process(jack_nframes_t nframes, void *arg) {
     (void)arg;
     if (!midi_inject_port) return 0;
@@ -57,8 +65,8 @@ static int passthrough_process(jack_nframes_t nframes, void *arg) {
     (void)arg;
     jack_default_audio_sample_t *out =
         (jack_default_audio_sample_t *)jack_port_get_buffer(passthrough_output_port, nframes);
-    jack_default_audio_sample_t *in =
+    const jack_default_audio_sample_t *in =
-        (jack_default_audio_sample_t *)jack_port_get_buffer(passthrough_input_port, nframes);
+        (const jack_default_audio_sample_t *)jack_port_get_buffer(passthrough_input_port, nframes);
     if (!out || !in) return 0;
     float *outf = out;
     const float *inf = in;
@@ -195,7 +203,7 @@ static int test_audio_pass_through(void) {
         waitpid(pid, NULL, 0);
         return 1;
     }
-    usleep(2200000); /* 2.2 seconds */
+    safe_usleep(2200000);
     int saw_input = passthrough_done;
     double rms = passthrough_total_samples > 0 ?
                  sqrt(passthrough_sum_sq / passthrough_total_samples) : 0.0;
@@ -313,7 +321,7 @@ static int test_looper_looping(void) {
         kill(pid, SIGTERM); waitpid(pid, NULL, 0);
         return 1;
     }
-    usleep(500000);               /* allow state to change (500ms) */
+    safe_usleep(500000);               /* allow state to change (500ms) */
 
     int sr = jack_get_sample_rate(client);
     continuous_sine = 0;          /* disable continuous tone */
@@ -337,10 +345,10 @@ static int test_looper_looping(void) {
         return 1;
     }
 
-    usleep(150000);               /* let beep start */
+    safe_usleep(150000);               /* let beep start */
 
     /* ensure beep is fully captured */
-    usleep(800000);   /* 0.8s after start of beep */
+    safe_usleep(800000);   /* 0.8s after start of beep */
 
     if (send_jack_note_on("looper:control", 1, 127) != 0) {
         jack_client_close(client);
@@ -349,7 +357,7 @@ static int test_looper_looping(void) {
     }
 
     /* wait enough time for several loops (4 seconds to be safe) */
-    usleep(4000000);
+    safe_usleep(4000000);
 
     jack_deactivate(client);
     jack_client_close(client);
@@ -390,7 +398,7 @@ static int test_multiple_channels(void) {
     }
     /* wait long enough for the looper's main loop to process the add command
        (it sleeps for 1 second between checks, so 1.5 s is safe) */
-    usleep(1500000);
+    safe_usleep(1500000);
 
     int found = 0;
     const char **ports = jack_get_ports(client, NULL, JACK_DEFAULT_AUDIO_TYPE, 0);
@@ -500,7 +508,7 @@ static int test_control_key_modifier(void) {
         fprintf(stderr, "  FAIL: send note 62 for loop\n");
         return 1;
     }
-    usleep(2000000);   /* wait for a few loops */
+    safe_usleep(2000000);
     jack_deactivate(client);
     jack_client_close(client);
     kill(pid, SIGTERM);
@@ -613,7 +621,7 @@ static int test_bind_channel(void) {
         fprintf(stderr, "  FAIL: toggle for loop\n");
         return 1;
     }
-    usleep(2000000);
+    safe_usleep(2000000);
     jack_deactivate(client);
     jack_client_close(client);
     kill(pid, SIGTERM);
@@ -741,7 +749,7 @@ static int test_bind_unbind(void) {
         fprintf(stderr, "  FAIL: toggle for loop\n");
         return 1;
     }
-    usleep(2000000);
+    safe_usleep(2000000);
     jack_deactivate(client);
     jack_client_close(client);
     kill(pid, SIGTERM);
@@ -776,7 +784,7 @@ static int test_remove_channel(void) {
         fprintf(stderr, "  FAIL: send note 60 failed\n");
         return 1;
     }
-    usleep(1500000);
+    safe_usleep(1500000);
     /* verify channel1_input exists */
     const char **ports = jack_get_ports(client, NULL, JACK_DEFAULT_AUDIO_TYPE, 0);
     int found = 0;
@@ -803,7 +811,7 @@ static int test_remove_channel(void) {
         fprintf(stderr, "  FAIL: send note 61 failed\n");
         return 1;
     }
-    usleep(1500000);
+    safe_usleep(1500000);
     /* verify channel1_input has disappeared */
     ports = jack_get_ports(client, NULL, JACK_DEFAULT_AUDIO_TYPE, 0);
     int still_found = 0;