vibe code the initial impl

main/detector.c

@@ -0,0 +1,51 @@
+#include <string.h>
+#include "detector.h"
+
+void detector_init(detector_t *d) { memset(d, 0, sizeof(*d)); d->state = DET_IDLE; }
+void detector_reset(detector_t *d) { d->state = DET_IDLE; d->hist = 0; }
+
+bool detector_is_match(float rms, float score, float min_rms, float threshold)
+{
+    return rms >= min_rms && score >= threshold;
+}
+
+bool detector_update(detector_t *d, bool match, uint32_t now_ms, const detector_cfg_t *cfg)
+{
+    uint32_t n = cfg->win_n < 1 ? 1 : (cfg->win_n > 32 ? 32 : cfg->win_n);
+    uint32_t m = cfg->win_m < 1 ? 1 : (cfg->win_m > n ? n : cfg->win_m);
+
+    switch (d->state) {
+    case DET_IDLE: {
+        d->hist = (d->hist << 1) | (match ? 1u : 0u);
+        uint32_t mask = (n == 32) ? 0xFFFFFFFFu : ((1u << n) - 1u);
+        if ((uint32_t)__builtin_popcount(d->hist & mask) >= m) {
+            d->state = DET_TRIGGERED;
+            d->triggers++;
+            return true;
+        }
+        break;
+    }
+    case DET_TRIGGERED:
+        d->state = DET_COOLDOWN;
+        d->cooldown_start_ms = now_ms;
+        d->hist = 0;
+        break;
+    case DET_COOLDOWN:
+        if ((uint32_t)(now_ms - d->cooldown_start_ms) >= cfg->cooldown_ms) {
+            d->state = DET_IDLE;
+            d->hist = 0;
+        }
+        break;
+    }
+    return false;
+}
+
+const char *detector_state_name(det_state_t s)
+{
+    switch (s) {
+    case DET_IDLE: return "IDLE";
+    case DET_TRIGGERED: return "TRIGGERED";
+    case DET_COOLDOWN: return "COOLDOWN";
+    }
+    return "?";
+}