xxx/mkfilter.h

/* mkfilter -- given n, compute recurrence relation
   to implement Butterworth, Bessel or Chebyshev filter of order n
   A.J. Fisher, University of York   <fisher@minster.york.ac.uk>
   September 1992 */

/* Header file */
#include <string.h>

#define VERSION     "4.6"
#undef  PI
#define PI              3.14159265358979323846  /* Microsoft C++ does not define M_PI ! */
#define TWOPI       (2.0 * PI)
#define EPS             1e-10
#define MAXORDER    12
#define MAXPZ       2048    /* .ge. 2*MAXORDER, to allow for doubling of poles in BP filter;
                                       high values needed for FIR filters */
#define MAXSTRING   256

typedef void (*proc)();
typedef unsigned int uint;

double atof(const char *);
int atoi(char *);
void exit(int);

extern const char *progname;
extern void readdata(char*, double&, int&, double*, int&, double*);

inline double sqr(double x)
{
    return x*x;
}

inline bool seq(char *s1, char *s2)
{
    return strcmp(s1, s2) == 0;
}

inline bool onebit(uint m)
{
    return (m != 0)  &&  ((m & m - 1) == 0);
}

inline double asinh(double x)
{
    /* Microsoft C++ does not define */
    return log(x + sqrt(1.0 + sqr(x)));
}

inline double fix(double x)
{
    /* nearest integer */
    return (x >= 0.0)  ?  floor(0.5 + x)  :  -floor(0.5 - x);
}