auxiliary.h

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#ifndef AUXILIARY_H
#define AUXILIARY_H

#ifdef HAVE_CONFIG_H
#include "config.h"
#endif

/* ---------------------------------------------------------------------- */
/* point arithmetic */

#include "potracelib.h"

struct point_s
{
  long x;
  long y;
};
typedef struct point_s point_t;

typedef potrace_dpoint_t dpoint_t;

static inline dpoint_t
dpoint (point_t p)
{
  dpoint_t res;
  res.x = p.x;
  res.y = p.y;
  return res;
}

static inline dpoint_t
interval (double lambda, dpoint_t a, dpoint_t b)
{
  dpoint_t res;

  res.x = a.x + lambda * (b.x - a.x);
  res.y = a.y + lambda * (b.y - a.y);
  return res;
}

/* ---------------------------------------------------------------------- */
/* some useful macros. */

/* integer arithmetic */

static inline int
mod (int a, int n)
{
  return a >= n ? a % n : a >= 0 ? a : n - 1 - (-1 - a) % n;
}

static inline int
floordiv (int a, int n)
{
  return a >= 0 ? a / n : -1 - (-1 - a) / n;
}

/* Note: the following work for integers and other numeric types. */
#undef sign
#undef abs
#undef min
#undef max
#undef sq
#undef cu
#define sign(x) ((x)>0 ? 1 : (x)<0 ? -1 : 0)
#define abs(a) ((a)>0 ? (a) : -(a))
#define min(a,b) ((a)<(b) ? (a) : (b))
#define max(a,b) ((a)>(b) ? (a) : (b))
#define sq(a) ((a)*(a))
#define cu(a) ((a)*(a)*(a))

#endif /* AUXILIARY_H */