Add an inline hibit calculation function

This commit was SVN r1073.

src/util/Makefile.am

@@ -13,6 +13,7 @@ headers = \
     argv.h \
     cmd_line.h \
     few.h \
+    hibit.h \
     if.h \
     output.h \
     path.h \

src/util/hibit.h

@@ -0,0 +1,38 @@
+/*
+ * $HEADER$
+ */
+
+#ifndef LAM_HIBIT_H
+#define LAM_HIBIT_H
+
+/**
+ * Calculates the highest bit in an integer
+ *
+ * @param value The integer value to examine
+ * @param start Position to start looking
+ *
+ * @returns pos Position of highest-set integer or -1 if none are set.
+ *
+ * Look at the integer "value" starting at position "start", and move
+ * to the right.  Return the index of the highest bit that is set to
+ * 1.
+ *
+ * WARNING: *NO* error checking is performed.  This is meant to be a
+ * fast inline function.
+ */
+static inline int lam_hibit(int value, int start)
+{
+  unsigned int mask;
+
+  --start;
+  mask = 1 << start;
+
+  for (; start >= 0; --start, mask >>= 1) {
+    if (value & mask) 
+      break;
+  }
+  
+  return start;
+}
+
+#endif /* LAM_HIBIT_H */