src/hid/gcode/auxiliary.h

   1 /*!
   2  * \file src/hid/gcode/auxiliary.h
   3  *
   4  * \brief This header file collects some general-purpose macros (and
   5  * static inline functions) that are used in various places.
   6  *
   7  * <hr>
   8  *
   9  * <h1><b>Copyright.</b></h1>\n
  10  *
  11  * PCB, interactive printed circuit board design
  12  *
  13  * Copyright (C) 2001-2007 Peter Selinger.
  14  *
  15  * This file is part of Potrace. It is free software and it is covered
  16  * by the GNU General Public License. See the file COPYING for details.
  17  */
  18
  19 #ifndef AUXILIARY_H
  20 #define AUXILIARY_H
  21
  22 #ifdef HAVE_CONFIG_H
  23 #include "config.h"
  24 #endif
  25
  26 /* ---------------------------------------------------------------------- */
  27 /* point arithmetic */
  28
  29 #include "potracelib.h"
  30
  31 struct point_s
  32 {
  33   long x;
  34   long y;
  35 };
  36 typedef struct point_s point_t;
  37
  38 typedef potrace_dpoint_t dpoint_t;
  39
  40 /*!
  41  * \brief Convert point_t to dpoint_t.
  42  */
  43 static inline dpoint_t
  44 dpoint (point_t p)
  45 {
  46   dpoint_t res;
  47   res.x = p.x;
  48   res.y = p.y;
  49   return res;
  50 }
  51
  52 /*!
  53  * \brief Range over the straight line segment [a,b] when lambda ranges
  54  * over [0,1].
  55  */
  56 static inline dpoint_t
  57 interval (double lambda, dpoint_t a, dpoint_t b)
  58 {
  59   dpoint_t res;
  60
  61   res.x = a.x + lambda * (b.x - a.x);
  62   res.y = a.y + lambda * (b.y - a.y);
  63   return res;
  64 }
  65
  66 /* ---------------------------------------------------------------------- */
  67 /* some useful macros. */
  68
  69 /* integer arithmetic */
  70
  71 /*!
  72  * \brief .
  73  *
  74  * The "mod" macro works correctly for negative a.
  75  * Also note that the test for a>=n, while redundant, speeds up the mod
  76  * function by 70% in the average case (significant since the program
  77  * spends about 16% of its time here - or 40% without the test).
  78  */
  79 static inline int
  80 mod (int a, int n)
  81 {
  82   return a >= n ? a % n : a >= 0 ? a : n - 1 - (-1 - a) % n;
  83 }
  84
  85 /*!
  86  * \brief The "floordiv" macro returns the largest integer
  87  * <= a/n, and again this works correctly for negative a, as long as
  88  * a,n are integers and n>0.
  89  */
  90 static inline int
  91 floordiv (int a, int n)
  92 {
  93   return a >= 0 ? a / n : -1 - (-1 - a) / n;
  94 }
  95
  96 /* Note: the following work for integers and other numeric types. */
  97 #undef sign
  98 #undef abs
  99 #undef min
 100 #undef max
 101 #undef sq
 102 #undef cu
 103 #define sign(x) ((x)>0 ? 1 : (x)<0 ? -1 : 0)
 104 #define abs(a) ((a)>0 ? (a) : -(a))
 105 #define min(a,b) ((a)<(b) ? (a) : (b))
 106 #define max(a,b) ((a)>(b) ? (a) : (b))
 107 #define sq(a) ((a)*(a))
 108 #define cu(a) ((a)*(a)*(a))
 109
 110 #endif /* AUXILIARY_H */