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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
#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;
/* 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;
}
/* 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. Note: 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). 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. */
/* 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 */
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