sample sketch for review

sample.ino

/* Sample sketch for review.
*/
#define USB Serial

const int usbBaud = 57600;
const int ledPin = 13;

const int commandBufferLength = 80;
static char commandBuffer[commandBufferLength];
char *commandMode;
char *commandValue;
int commandBufferPosition = 0;


int readline(int incomingChar, char *buffer, int len, int &bufferPosition) {
  int totalLength;
  if (incomingChar > 0) {
    switch (incomingChar) {
      case '\n':
        break;
      case '\r':
        totalLength = bufferPosition;
        bufferPosition = 0;
        return totalLength;
      default:
        if (bufferPosition < len-1) {
          buffer[bufferPosition] = incomingChar;
          buffer[bufferPosition+1] = 0;
          bufferPosition++;
        }
    }
  }
  return -1;
}


void setup() {
  pinMode(ledPin, OUTPUT);
  USB.begin(usbBaud);
}


void loop() {
  if (readline(USB.read(), commandBuffer, commandBufferLength, commandBufferPosition) > 0) {
    commandMode = strtok(commandBuffer, " ");

    if (strcmp(commandMode, "led") == 0) {
      commandValue = strtok(NULL, " ");

      if (strcmp(commandValue, "on") == 0) {
        digitalWrite(ledPin, HIGH);

      } else if (strcmp(commandValue, "off") == 0) {
        digitalWrite(ledPin, LOW);

      } else {
        USB.println("value not understood");
      }

    } else {
      USB.print("error: could not parse command '");
      USB.print(commandBuffer);
      USB.println("'");
    }
  }
}