improved validation of RFSniffer pulse_length parameter + cpp-style

Author: Michel Korfhage

RPi_utils/RFSniffer.cpp

@@ -1,65 +1,81 @@
 /*
-  RFSniffer
+   RFSniffer
 
-  Usage: ./RFSniffer [<pulseLength>]
-  [] = optional
+Usage: ./RFSniffer [<pulseLength>]
+[] = optional
 
-  Hacked from http://code.google.com/p/rc-switch/
-  by @justy to provide a handy RF code sniffer
-*/
+Hacked from http://code.google.com/p/rc-switch/
+by @justy to provide a handy RF code sniffer
+Adapted by korfhage(dot)michel(at)web(dot)de
+ */
+
+#include <cstdlib>
+#include <cerrno>
+
+#include <string>
+#include <iostream>
 
-#include "../rc-switch/RCSwitch.h"
-#include <stdlib.h>
-#include <stdio.h>
 #include <unistd.h>
-     
-     
-RCSwitch mySwitch;
- 
 
+#include "../rc-switch/RCSwitch.h"
+
+using std::cout;
+using std::endl;
+
+// This pin is not the first pin on the RPi GPIO header!
+// Consult https://projects.drogon.net/raspberry-pi/wiringpi/pins/
+// for more information.
+constexpr int PIN = 2;
+
+template<class dest>
+dest cast(char* param, unsigned int& errorCode)
+{
+	char* end;
+	errno = 0;
+	long l = std::strtol(param, &end, 10); 	
+	cout << "set pulse length to " << l << endl;
+	dest ret(l);
+	if(errno || ret != l) errorCode = errno;
+	return ret;
+}
 
 int main(int argc, char *argv[]) {
-  
-     // This pin is not the first pin on the RPi GPIO header!
-     // Consult https://projects.drogon.net/raspberry-pi/wiringpi/pins/
-     // for more information.
-     int PIN = 2;
-     
-     if(wiringPiSetup() == -1) {
-       printf("wiringPiSetup failed, exiting...");
-       return 0;
-     }
-
-     int pulseLength = 0;
-     if (argv[1] != NULL) pulseLength = atoi(argv[1]);
-
-     mySwitch = RCSwitch();
-     if (pulseLength != 0) mySwitch.setPulseLength(pulseLength);
-     mySwitch.enableReceive(PIN);  // Receiver on interrupt 0 => that is pin #2
-     
-    
-     while(1) {
-  
-      if (mySwitch.available()) {
-    
-        int value = mySwitch.getReceivedValue();
-    
-        if (value == 0) {
-          printf("Unknown encoding\n");
-        } else {    
-   
-          printf("Received %i\n", mySwitch.getReceivedValue() );
-        }
-    
-        fflush(stdout);
-        mySwitch.resetAvailable();
-      }
-      usleep(100); 
-  
-  }
-
-  exit(0);
+	if(wiringPiSetup() == -1) {
+		cout << "wiringPiSetup failed, exiting..." << endl;
+		return 101;
+	}
+
+	RCSwitch mySwitch;
+
+	if(argv[1])
+	{
+		unsigned int error = 0;
+		// first argument will parsed as the pulselength
+		int pulseLength = cast<int>(argv[1], error);
+		if(error)
+		{
+			cout << "invalid first argument! needs to be signed number." << endl;
+			return 102;
+		}
+		if (pulseLength) mySwitch.setPulseLength(pulseLength);
+	}
+
+	mySwitch.enableReceive(PIN);  // Receiver on interrupt 0 => that is pin #2
 
+	while(1) {
+		if (mySwitch.available()) {
+			auto value = mySwitch.getReceivedValue();
+			if (!value) {
+				cout << "Unknown encoding";
+			} else {    
+				cout << "Received " << value;
+			}
+			cout << endl;
+			mySwitch.resetAvailable();
+		}
+		usleep(100); 
 
+	}
+	return 0;
 }