From a321da8fb65b5fb584d8cd7d6fb0a870d124002c Mon Sep 17 00:00:00 2001
From: windowsair <msdn_02@sina.com>
Date: Thu, 20 Jan 2022 11:51:09 +0800
Subject: [PATCH] fix(uart): Parse baudrate and does not send

---
 README.md          |  4 ++++
 main/uart_bridge.c | 23 +++++++++++++++++++++--
 2 files changed, 25 insertions(+), 2 deletions(-)

diff --git a/README.md b/README.md
index 25d8522..97efa3e 100644
--- a/README.md
+++ b/README.md
@@ -266,6 +266,10 @@ Send data   ->  TCP  ->  Uart TX -> external devices
 Recv data   <-  TCP  <-  Uart Rx <- external devices
 ```
 
+When the TCP connection is established, bridge will try to resolve the text sent for the first time. When the text is a valid baud rate, bridge will switch to it.
+For example, sending the ASCII text `115200` will switch the baud rate to 115200.
+
+
 For performance reasons, this feature is not enabled by default. You can can modify [wifi_configuration.h](main/wifi_configuration.h) to turn it on.
 
 
diff --git a/main/uart_bridge.c b/main/uart_bridge.c
index c46a5eb..5ff30b6 100644
--- a/main/uart_bridge.c
+++ b/main/uart_bridge.c
@@ -87,6 +87,23 @@ static void uart_bridge_reset() {
     is_conn_valid = false;
 }
 
+static int num_digits(int n) {
+    if (n < 10)
+        return 1;
+    if (n < 100)
+        return 2;
+    if (n < 1000)
+        return 3;
+    if (n < 10000)
+        return 4;
+    if (n < 100000)
+        return 5;
+    if (n < 1000000)
+        return 6;
+
+    return 7;
+}
+
 /*
  * This function will be call in Lwip in each event on netconn
  */
@@ -241,10 +258,12 @@ void uart_bridge_task() {
                             memcpy(tmp_buff, buffer, len_buf);
                             tmp_buff[len_buf] = '\0';
                             int baudrate = atoi(tmp_buff);
-                            if (baudrate > 0 && baudrate < 2000000) {
-                                ESP_LOGI(UART_TAG, "change baud:%d\r\n", baudrate);
+                            if (baudrate > 0 && baudrate < 2000000 && num_digits(baudrate) == len_buf) {
+                                ESP_LOGI(UART_TAG, "change baud:%d", baudrate);
                                 uart_set_baudrate(UART_NUM_0, baudrate);
                                 uart_set_baudrate(UART_NUM_1, baudrate);
+                                is_first_time_recv = false;
+                                continue;
                             }
                         }
                         is_first_time_recv = false;