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90 lines
2.3 KiB
90 lines
2.3 KiB
/* Copyright (C) 2001-2017 Peter Selinger.
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* This file is part of Potrace. It is free software and it is covered
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* by the GNU General Public License. See the file COPYING for details. */
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/* This header file collects some general-purpose macros (and static
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* inline functions) that are used in various places. */
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#ifndef AUXILIARY_H
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#define AUXILIARY_H
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#ifdef HAVE_CONFIG_H
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#include <config.h>
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#endif
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#include <stdlib.h>
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/* ---------------------------------------------------------------------- */
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/* point arithmetic */
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#include "potracelib.h"
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struct point_s
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{
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long x;
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long y;
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};
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typedef struct point_s point_t;
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typedef potrace_dpoint_t dpoint_t;
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/* convert point_t to dpoint_t */
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static inline dpoint_t dpoint( point_t p )
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{
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dpoint_t res;
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res.x = p.x;
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res.y = p.y;
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return res;
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}
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/* range over the straight line segment [a,b] when lambda ranges over [0,1] */
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static inline dpoint_t interval( double lambda, dpoint_t a, dpoint_t b )
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{
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dpoint_t res;
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res.x = a.x + lambda * ( b.x - a.x );
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res.y = a.y + lambda * ( b.y - a.y );
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return res;
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}
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/* ---------------------------------------------------------------------- */
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/* some useful macros. Note: the "mod" macro works correctly for
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* negative a. Also note that the test for a>=n, while redundant,
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* speeds up the mod function by 70% in the average case (significant
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* since the program spends about 16% of its time here - or 40%
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* without the test). The "floordiv" macro returns the largest integer
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* <= a/n, and again this works correctly for negative a, as long as
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* a,n are integers and n>0. */
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/* integer arithmetic */
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static inline int mod( int a, int n )
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{
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return a >= n ? a % n : a >= 0 ? a : n - 1 - ( -1 - a ) % n;
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}
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static inline int floordiv( int a, int n )
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{
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return a >= 0 ? a / n : -1 - ( -1 - a ) / n;
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}
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/* Note: the following work for integers and other numeric types. */
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#undef sign
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#undef abs
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#undef min
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#undef max
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#undef sq
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#undef cu
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#define sign( x ) ( ( x ) > 0 ? 1 : ( x ) < 0 ? -1 : 0 )
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#define abs( a ) ( ( a ) > 0 ? ( a ) : -( a ) )
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#define min( a, b ) ( ( a ) < ( b ) ? ( a ) : ( b ) )
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#define max( a, b ) ( ( a ) > ( b ) ? ( a ) : ( b ) )
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#define sq( a ) ( ( a ) * ( a ) )
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#define cu( a ) ( ( a ) * ( a ) * ( a ) )
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#endif /* AUXILIARY_H */
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