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/* 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. */
/* This header file collects some general-purpose macros (and static
inline functions) that are used in various places. */
#ifndef AUXILIARY_H
#define AUXILIARY_H
#include "config.h"
/* ---------------------------------------------------------------------- */
/* point arithmetic */
#include "potracelib.h"
struct point_s {
long x;
long y;
};
typedef struct point_s point_t;
typedef potrace_dpoint_t dpoint_t;
/* convert point_t to dpoint_t */
PCB_INLINE dpoint_t dpoint(point_t p)
{
dpoint_t res;
res.x = p.x;
res.y = p.y;
return res;
}
/* range over the straight line segment [a,b] when lambda ranges over [0,1] */
PCB_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;
}
/* ---------------------------------------------------------------------- */
/* Note: the "mod" function 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). The "floordiv" function returns the largest integer
<= a/n, and again this works correctly for negative a, as long as
a,n are integers and n>0. */
/* integer arithmetic */
PCB_INLINE int mod(int a, int n)
{
return a >= n ? a % n : a >= 0 ? a : n - 1 - (-1 - a) % n;
}
PCB_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 */
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