/*!
 * \file src/hid/gcode/auxiliary.h
 *
 * \brief This header file collects some general-purpose macros (and
 * static inline functions) that are used in various places.
 *
 * <hr>
 *
 * <h1><b>Copyright.</b></h1>\n
 *
 * PCB, interactive printed circuit board design
 *
 * Copyright (C) 2001-2007 Peter Selinger.
 *
 * This file is part of Potrace. It is free software and it is covered
 * by the GNU General Public License. See the file COPYING for details.
 */

#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;

/*!
 * \brief Convert point_t to dpoint_t.
 */
static inline dpoint_t
dpoint (point_t p)
{
  dpoint_t res;
  res.x = p.x;
  res.y = p.y;
  return res;
}

/*!
 * \brief Range over the straight line segment [a,b] when lambda ranges
 * over [0,1].
 */
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 */

/*!
 * \brief .
 *
 * The "mod" macro works correctly for negative a.
 * Also note that the test for a>=n, while redundant, speeds up the mod
 * function by 70% in the average case (significant since the program
 * spends about 16% of its time here - or 40% without the test).
 */
static inline int
mod (int a, int n)
{
  return a >= n ? a % n : a >= 0 ? a : n - 1 - (-1 - a) % n;
}

/*!
 * \brief The "floordiv" macro returns the largest integer
 * <= a/n, and again this works correctly for negative a, as long as
 * a,n are integers and n>0.
 */
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 */
