Good C / C++ macros

macros.h

//the Arduino map function. 
#define MAP(x, in_min, in_max, out_min, out_max) (((x) - (in_min)) * ((out_max) - (out_min)) / ((in_max) - (in_min)) + (out_min))

#define SIGN(i) ((i)>0? 1:(i)<0?-1:0)

#define MAX(a, b) ((a)>(b)?(a):(b))

#define MIN(a, b) ((a)<(b)?(a):(b))

#define ABS(a) ((a)<0?(0-(a)):(a))

#if defined DEBUG
    #define TRACE( format, ... )   printf( "%s::%s(%d)" format, __FILE__, __FUNCTION__,  __LINE__, __VA_ARGS__ )
#else
    #define TRACE( format, ... )
#endif

//https://stackoverflow.com/a/1772320/663416

//if x is true, y better be true. Used with assert
#define IMPLIES(x, y) (!(x) || (y))
/*
void foo(int array[], int n) {
  assert(IMPLIES(n > 0, array != NULL));
  ...
*/

#define SWAP(x, y, T) do { T tmp = (x); (x) = (y); (y) = tmp; } while(0)

#define SORT2(a, b, T) do { if ((a) > (b)) SWAP((a), (b), T); } while (0)

//set an array (d) of size n to v
#define SET(d, n, v) do{ size_t i_, n_; for (n_ = (n), i_ = 0; n_ > 0; --n_, ++i_) (d)[i_] = (v); } while(0)
#define ZERO(d, n) SET(d, n, 0)

//calculate the number of rows in a 1 or 2 dimensional matrix
#define ROWS(x) ( sizeof(x) / sizeof(x[0]) )

//calculate the number of columns in a 2 dimensional matrix
#define COLS(x) ( sizeof(x[0]) / sizeof(x[0][0]) )

//State machine without a state variable
//https://stackoverflow.com/a/1772333/663416
 #define FSM            for(;;)
 #define STATE(x)       x##_s 
 #define NEXTSTATE(x)   goto x##_s

/*
 FSM {
    STATE(s1):
      ... do stuff ...
      NEXTSTATE(s2);

    STATE(s2):
      ... do stuff ...
      if (k<0) NEXTSTATE(s2); 
      // fallthrough as the switch() cases 

    STATE(s3):
      ... final stuff ...
      break;  // Exit from the FSM
 } 
*/