Refactor the link state machine to switch statements for clarity

src/main.c

@@ -630,6 +630,14 @@ void bt_ctlr_assert_handle(char *file, u32_t line)
 DEVICE_INIT(hci_uart, "hci_uart", &h5_open, NULL, NULL,
 	    APPLICATION, CONFIG_KERNEL_INIT_PRIORITY_DEVICE);
 
+enum h5_pkt_types {
+  H5_UNKNOWN = -1,
+  H5_SYNC,
+  H5_SYNC_RESPONSE,
+  H5_CONFIG,
+  H5_CONFIG_RESPONSE,
+};
+
 bool _link_ctrl_memcmp(struct net_buf const * buf, u8_t const * const ref) {
 	return !memcmp(buf->data, ref, 2);
 }
@@ -654,6 +662,19 @@ static void _send_link_control(u8_t const * const buf, u8_t len) {
 	h5_send(buf, HCI_3WIRE_LINK_PKT, len);
 }
 
+int packet_get_type(struct net_buf const * buf) {
+    if (packet_is_sync(buf)){
+        return H5_SYNC;
+    } else if (packet_is_sync_response(buf)) {
+        return H5_SYNC_RESPONSE;
+    } else if (packet_is_config(buf)) {
+        return H5_CONFIG;
+    } else if (packet_is_config_response(buf)) {
+        return H5_CONFIG_RESPONSE;
+    }
+    return H5_UNKNOWN;
+}
+
 static void h5_send_sync(void) {
 	_send_link_control(sync_req, sizeof(sync_req));
 }
@@ -705,15 +726,15 @@ void gpio_init() {
 }
 
 static linkstate_t do_uninit(struct net_buf const *buf) {
-    if (packet_is_sync(buf)) {
+    switch (packet_get_type(buf)) {
+    case H5_SYNC:
         h5_send_sync_response();
         return UNINIT;
-    }
+    case H5_SYNC_RESPONSE:
-    if (packet_is_sync_response(buf)) {
         h5_send_config();
         LOG_DBG("RX'd SYNC RESPONSE: UNINIT -> INIT");
         return INIT;
-    } else {
+    default:
         LOG_DBG("RX'd Incorrect Type: UNINIT -> UNINIT");
         /* SYNC is the answer to any non-SYNC_RESP packets in UNINIT state */
         h5_send_sync();
@@ -722,49 +743,44 @@ static linkstate_t do_uninit(struct net_buf const *buf) {
 }
 
 static linkstate_t do_init(struct net_buf const *buf) {
-    if (packet_is_config_response(buf)) {
+    switch (packet_get_type(buf)) {
+    case H5_SYNC:
+        LOG_DBG("RX'd SYNC: INIT -> INIT");
+        h5_send_sync_response();
+        return INIT;
+    case H5_CONFIG:
+        LOG_DBG("RX'd CONFIG: INIT -> INIT");
+        h5_send_config_response();
+        return INIT;
+    case H5_CONFIG_RESPONSE:
         h5.tx_win = conf_rsp[2] & 0x7;
         h5.tx_seq = 0;
         h5.tx_ack = 0;
         LOG_DBG("Finished H5 configuration, tx_win %u: INIT -> ACTIVE", h5.tx_win);
         return ACTIVE;
-    }
+    default:
-
-    if (packet_is_sync(buf)) {
-        LOG_DBG("RX'd SYNC: INIT -> INIT");
-        h5_send_sync_response();
-    }
-
-    if (packet_is_config(buf)) {
-        LOG_DBG("RX'd CONFIG: INIT -> INIT");
-        h5_send_config_response();
-    } else {
         LOG_DBG("RX'd Other: INIT -> INIT");
-    }
         return INIT;
     }
+}
 
 static linkstate_t do_active(struct net_buf *buf) {
-    if (packet_is_sync_response(buf)) {
+    switch (packet_get_type(buf)) {
+    case H5_SYNC:
+        LOG_DBG("SYNC in ACTIVE state: ACTIVE -> UNINIT");
+        return UNINIT;
+    case H5_SYNC_RESPONSE:
         LOG_DBG("Bad packet for ACTIVE state: ACTIVE -> UNINIT");
         h5_send_sync();
         return UNINIT;
-    }
+    case H5_CONFIG:
-
-    if (packet_is_sync(buf)){
-        LOG_DBG("SYNC in ACTIVE state: ACTIVE -> UNINIT");
-        return UNINIT;
-    }
-
-    if (packet_is_config(buf)) {
         h5_send_config_response();
         LOG_DBG("RX'd CONFIG: ACTIVE -> ACTIVE");
-    }
+        return ACTIVE;
-
+    case H5_CONFIG_RESPONSE:
-    if (packet_is_config_response(buf)) {
         LOG_DBG("RX'd CONFIG RESPONSE: ACTIVE -> ACTIVE");
-    }
+        return ACTIVE;
-
+    default:
         // Presumably something from the controller
         if (bt_buf_get_type(buf) == BT_BUF_EVT) {
             LOG_DBG("RX'd CONTROLLER EVENT: ACTIVE -> ACTIVE");
@@ -774,6 +790,7 @@ static linkstate_t do_active(struct net_buf *buf) {
         }
         return ACTIVE;
     }
+}
 
 void main(void)
 {