Harden firmware state and transfer handling

src/hal/usb_hid.cpp

@@ -1,6 +1,7 @@
 #include "usb_hid.h"
 #include <Arduino.h>
 #include <HID.h>
+#include <string.h>
 
 // ── HID Report Descriptor: Keyboard + Consumer Control ───────────────────────
 // Host-Kommunikation außerhalb von HID läuft separat über USB CDC (SerialUSB).
@@ -67,30 +68,140 @@ struct ConsumerReport {
     uint16_t usage;
 };
 
-void usb_hid_init() {}
+static uint8_t s_key_refcount[256] = {};
+static uint8_t s_modifier_refcount[8] = {};
 
-void usb_hid_send_key(uint8_t keycode, uint8_t modifier)
+struct ConsumerState {
+    uint16_t usage;
+    uint8_t  refcount;
+    uint32_t order;
+};
+
+static constexpr uint8_t CONSUMER_STATE_SLOTS = 8;
+static ConsumerState s_consumer_state[CONSUMER_STATE_SLOTS] = {};
+static uint32_t s_consumer_order = 0;
+
+static void send_keyboard_state()
 {
     KeyboardReport report = {};
-    report.modifier    = modifier;
-    report.keycodes[0] = keycode;
+
+    for (uint8_t bit = 0; bit < 8; bit++) {
+        if (s_modifier_refcount[bit] > 0)
+            report.modifier |= static_cast<uint8_t>(1u << bit);
+    }
+
+    uint8_t out = 0;
+    for (uint16_t key = 1; key < 256 && out < 6; key++) {
+        if (s_key_refcount[key] > 0)
+            report.keycodes[out++] = static_cast<uint8_t>(key);
+    }
+
     HID().SendReport(HID_REPORT_ID_KEYBOARD, &report, sizeof(report));
 }
 
-void usb_hid_release_key()
+static void send_consumer_state()
 {
-    KeyboardReport report = {};
-    HID().SendReport(HID_REPORT_ID_KEYBOARD, &report, sizeof(report));
-}
+    uint16_t usage = 0;
+    uint32_t newest = 0;
+
+    for (uint8_t i = 0; i < CONSUMER_STATE_SLOTS; i++) {
+        if (s_consumer_state[i].refcount > 0 &&
+            s_consumer_state[i].order >= newest)
+        {
+            newest = s_consumer_state[i].order;
+            usage = s_consumer_state[i].usage;
+        }
+    }
 
-void usb_hid_send_consumer(uint16_t usage)
-{
     ConsumerReport report = { usage };
     HID().SendReport(HID_REPORT_ID_CONSUMER, &report, sizeof(report));
 }
 
-void usb_hid_release_consumer()
+void usb_hid_init()
 {
-    ConsumerReport report = { 0 };
-    HID().SendReport(HID_REPORT_ID_CONSUMER, &report, sizeof(report));
+    memset(s_key_refcount, 0, sizeof(s_key_refcount));
+    memset(s_modifier_refcount, 0, sizeof(s_modifier_refcount));
+    memset(s_consumer_state, 0, sizeof(s_consumer_state));
+    s_consumer_order = 0;
+}
+
+void usb_hid_send_key(uint8_t keycode, uint8_t modifier)
+{
+    if (keycode != 0 && s_key_refcount[keycode] < 0xFF)
+        s_key_refcount[keycode]++;
+
+    for (uint8_t bit = 0; bit < 8; bit++) {
+        if ((modifier & (1u << bit)) != 0 && s_modifier_refcount[bit] < 0xFF)
+            s_modifier_refcount[bit]++;
+    }
+
+    send_keyboard_state();
+}
+
+void usb_hid_release_key(uint8_t keycode, uint8_t modifier)
+{
+    if (keycode != 0 && s_key_refcount[keycode] > 0)
+        s_key_refcount[keycode]--;
+
+    for (uint8_t bit = 0; bit < 8; bit++) {
+        if ((modifier & (1u << bit)) != 0 && s_modifier_refcount[bit] > 0)
+            s_modifier_refcount[bit]--;
+    }
+
+    send_keyboard_state();
+}
+
+void usb_hid_release_all_keys()
+{
+    memset(s_key_refcount, 0, sizeof(s_key_refcount));
+    memset(s_modifier_refcount, 0, sizeof(s_modifier_refcount));
+    send_keyboard_state();
+}
+
+void usb_hid_send_consumer(uint16_t usage)
+{
+    ConsumerState* free_slot = nullptr;
+
+    for (uint8_t i = 0; i < CONSUMER_STATE_SLOTS; i++) {
+        ConsumerState& state = s_consumer_state[i];
+        if (state.refcount > 0 && state.usage == usage) {
+            if (state.refcount < 0xFF) state.refcount++;
+            state.order = ++s_consumer_order;
+            send_consumer_state();
+            return;
+        }
+        if (state.refcount == 0 && free_slot == nullptr)
+            free_slot = &state;
+    }
+
+    if (free_slot != nullptr) {
+        free_slot->usage = usage;
+        free_slot->refcount = 1;
+        free_slot->order = ++s_consumer_order;
+    }
+
+    send_consumer_state();
+}
+
+void usb_hid_release_consumer(uint16_t usage)
+{
+    for (uint8_t i = 0; i < CONSUMER_STATE_SLOTS; i++) {
+        ConsumerState& state = s_consumer_state[i];
+        if (state.refcount > 0 && state.usage == usage) {
+            state.refcount--;
+            if (state.refcount == 0) {
+                state.usage = 0;
+                state.order = 0;
+            }
+            break;
+        }
+    }
+
+    send_consumer_state();
+}
+
+void usb_hid_release_all_consumers()
+{
+    memset(s_consumer_state, 0, sizeof(s_consumer_state));
+    send_consumer_state();
 }