Merge pull request #6 from saurabhb17/master

minor additions

1 files changed, 89 insertions, 0 deletions

diff --git a/potrace/auxiliary.h b/potrace/auxiliary.h
new file mode 100644
index 0000000..f96c6a8
--- /dev/null
+++ b/potrace/auxiliary.h
@@ -0,0 +1,89 @@
+/* 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 */