/* Copyright (C) 2001-2019 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 #endif #include /* ---------------------------------------------------------------------- */ /* 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 */