refactor: extract duplicate isHex/parseHex into shared serial_utils.h

Fixes #19

src/client.cpp

@@ -10,6 +10,7 @@
 #include <esp_log.h>
 #include "version.h"
 #include "ecdh_helper.h"
+#include "serial_utils.h"
 
 static const char *TAG = "client";
 
@@ -126,20 +127,6 @@ class MyClientCallbacks : public NimBLEClientCallbacks {
 
 static MyClientCallbacks clientCallbacks;
 
-static bool isHex(const String &hex) {
-    for (int i = 0; i < hex.length(); i++) {
-        char c = hex.charAt(i);
-        if (!((c >= '0' && c <= '9') || (c >= 'A' && c <= 'F'))) return false;
-    }
-    return true;
-}
-
-static void parseHex(const String &hex, uint8_t *out, int len) {
-    for (int i = 0; i < len; i++) {
-        out[i] = (uint8_t)strtoul(hex.substring(i * 2, i * 2 + 2).c_str(), nullptr, 16);
-    }
-}
-
 static void buildAesPacket(uint8_t cmd, uint8_t *packet) {
     uint32_t s = ++seq;
     packet[0] = (s >> 24) & 0xFF;

src/main.cpp

@@ -13,6 +13,7 @@
 #include <esp_log.h>
 #include "version.h"
 #include "ecdh_helper.h"
+#include "serial_utils.h"
 
 static const char *TAG = "server";
 
@@ -211,20 +212,6 @@ static bool decryptAesGcm(const uint8_t *packet, int idx, uint8_t *outCmd) {
     return true;
 }
 
-static bool isHex(const String &hex) {
-    for (int i = 0; i < hex.length(); i++) {
-        char c = hex.charAt(i);
-        if (!((c >= '0' && c <= '9') || (c >= 'A' && c <= 'F'))) return false;
-    }
-    return true;
-}
-
-static void parseHex(const String &hex, uint8_t *out, int len) {
-    for (int i = 0; i < len; i++) {
-        out[i] = (uint8_t)strtoul(hex.substring(i * 2, i * 2 + 2).c_str(), nullptr, 16);
-    }
-}
-
 static void otaReset() {
     otaInProgress = false;
     otaHandle = 0;

src/serial_utils.h

@@ -0,0 +1,18 @@
+// SPDX-License-Identifier: GPL-3.0-or-later
+#pragma once
+
+#include <Arduino.h>
+
+static inline bool isHex(const String &hex) {
+    for (int i = 0; i < hex.length(); i++) {
+        char c = hex.charAt(i);
+        if (!((c >= '0' && c <= '9') || (c >= 'A' && c <= 'F'))) return false;
+    }
+    return true;
+}
+
+static inline void parseHex(const String &hex, uint8_t *out, int len) {
+    for (int i = 0; i < len; i++) {
+        out[i] = (uint8_t)strtoul(hex.substring(i * 2, i * 2 + 2).c_str(), nullptr, 16);
+    }
+}