Arduino: SoftwareSerial with printf

Playing around with Arduino finally implemented the printf. The floating point library can be only enabled by modifying the IDE Utilizar float con sprintf() y derivados en Arduino.

/* simple implementation of printf for SoftwareSerial */

#include <SoftwareSerial.h>
#include <inttypes.h>

#define PD0  0
#define PD1  1

class mySerial : public SoftwareSerial {

  public:
    mySerial(uint8_t receivePin, uint8_t transmitPin,
      bool inverse_logic = false) :
      SoftwareSerial(receivePin, transmitPin,inverse_logic) {}

    virtual size_t write(uint8_t byte) {
      return SoftwareSerial::write(byte);
    }

    int printf(char* fmt, ...) {
      char buff[256];
      va_list args;
      va_start(args, fmt);
      int return_status = vsnprintf(buff, sizeof(buff), fmt, args);
      va_end(args);
      uint8_t *s = (uint8_t *)&buff;
      while (*s) write(*s++);
      return return_status;
    }

};

mySerial m(PD0,PD1);

void setup() {
  m.begin(9600);

  m.print("Hello from Arduino!\n");
  m.printf("%s 0x%x %d %4o\n", "Hello", 0x80, 333, 128);
  m.printf("%16s x\n", "Hello");
  m.printf("%08x %e\n", 0x1234, 1e-10);

  m.printf("Floats:\n");
  m.printf("%.3lf %e\n", 3.14159f, 3.14159f);

}

void loop() {
}

If you use the Arduino Makefile
add following line to enable printf.

LDFLAGS  += -Wl,-lprintf_flt,-u,vfprintf

The Output

Hello from Arduino!
Hello 0x80 333  200
           Hello x
00001234 1.000000e-10
Floats:
3.142 3.141590e+00