Code optimization, bugfix DHCP settings.

Author: budulinek

README.md

@@ -56,6 +56,7 @@ Get the hardware (cheap clones from China are sufficient) and connect together:
       Rx0 <-> RO<br>
       Pin 6 <-> DE,RE
 
+
 Here is my setup:
 Terminal shield + Arduino Nano + W5500 eth shield (RobotDyn) + TTL to RS485 module (HW automatic flow control)
 <img src="/pics/HW.jpg" alt="01" style="zoom:100%;" />
@@ -93,7 +94,7 @@ The code was tested on Arduino Nano, Uno and Mega, ethernet chips W5100 and W550
 
 #### Ethernet socket
 
-The default Ethernet.h library determines MAX_SOCK_NUM by microcontroller RAM (not by Ethernet chip type). So if you use W5500 (which has 8 sockets available) on Arduino Nano, only 4 sockets will be used. If you want to force the library to use 8 sockets, edit https://github.com/arduino-libraries/Ethernet/blob/master/src/Ethernet.h#L36 
+The default Ethernet.h library determines MAX_SOCK_NUM by microcontroller RAM (not by Ethernet chip type). So if you use W5500 (which has 8 sockets available) on Arduino Nano, only 4 sockets will be used. If you want to force the library to use 8 sockets, redefine MAX_SOCK_NUM in advanced settings in the sketch.
 
 #### Memory
 

arduino-modbus-rtu-tcp-gateway/04-webserver.ino

@@ -205,10 +205,11 @@ void processPost(char postParameter[]) {
     char *sav2 = NULL;            // for inner strtok_r
     paramKey = strtok_r(point, "=", &sav2);   // inner strtok_r, use sav2
     paramValue = strtok_r(NULL, "=", &sav2);
-    if (!paramValue) continue;
+    point = strtok_r(NULL, "&", &sav1);
+    if (!paramValue)
+      continue;      // do not process POST parameter if there is no parameter value
     byte paramKeyByte = atoi(paramKey);
     unsigned long paramValueUlong = atol(paramValue);
-
     switch (paramKeyByte) {
       case POST_NONE:                     // reserved, because atoi / atol returns NULL in case of error
         break;
@@ -307,7 +308,6 @@ void processPost(char postParameter[]) {
       default:
         break;
     }
-    point = strtok_r(NULL, "&", &sav1);
   }     // while (point != NULL)
   switch (action) {
     case FACTORY: