1 files changed, 77 insertions, 0 deletions
diff --git a/plug-ins/file-dds/imath.h b/plug-ins/file-dds/imath.h
new file mode 100644
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+++ b/plug-ins/file-dds/imath.h
@@ -0,0 +1,77 @@
+/*
+ * DDS GIMP plugin
+ *
+ * Copyright (C) 2004-2012 Shawn Kirst <skirst@gmail.com>,
+ * with parts (C) 2003 Arne Reuter <homepage@arnereuter.de> where specified.
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ */
+
+#ifndef __IMATH_H__
+#define __IMATH_H__
+
+#ifndef MIN
+# ifdef __GNUC__
+#  define MIN(a, b)  ({typeof(a) _a=(a); typeof(b) _b=(b); _a < _b ? _a : _b;})
+# else
+#  define MIN(a, b)  ((a) < (b) ? (a) : (b))
+# endif
+#endif
+
+#ifndef MAX
+# ifdef __GNUC__
+#  define MAX(a, b)  ({typeof(a) _a=(a); typeof(b) _b=(b); _a > _b ? _a : _b;})
+# else
+#  define MAX(a, b)  ((a) > (b) ? (a) : (b))
+# endif
+#endif
+
+#define IS_POW2(x)     (!((x) & ((x) - 1)))
+#define IS_MUL4(x)     (((x) & 3) == 0)
+
+/* round integer x up to next multiple of 4 */
+#define RND_MUL4(x)    ((x) + (4 - ((x) & 3)))
+
+static inline int
+mul8bit (int a,
+         int b)
+{
+  int t = a * b + 128;
+
+  return (t + (t >> 8)) >> 8;
+}
+
+static inline int
+blerp (int a,
+       int b,
+       int x)
+{
+   return a + mul8bit(b - a, x);
+}
+
+static inline int
+icerp (int a,
+       int b,
+       int c,
+       int d,
+       int x)
+{
+  int p = (d - c) - (a - b);
+  int q = (a - b) - p;
+  int r = c - a;
+
+  return (x * (x * (x * p + (q << 7)) + (r << 14)) + (b << 21)) >> 21;
+}
+
+#endif /* __IMATH_H__ */