multiple zeta values: make crandall_Y_loop helper function reentrant.

[ginac.git] / ginac / utils.h

diff --git a/ginac/utils.h b/ginac/utils.h
index ebfc9804314a789d6657609ac1b80a9942a03a0c..a4af3300e38d8c9d45370a30d908513a6759c6f2 100644 (file)
--- a/ginac/utils.h
+++ b/ginac/utils.h
@@ -4,7 +4,7 @@
  *  of any interest to the user of the library. */
 
 /*
- *  GiNaC Copyright (C) 1999-2007 Johannes Gutenberg University Mainz, Germany
+ *  GiNaC Copyright (C) 1999-2008 Johannes Gutenberg University Mainz, Germany
  *
  *  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
@@ -44,6 +44,13 @@ class dunno {};
 
 unsigned log2(unsigned n);
 
+/** Rotate bits of unsigned value by one bit to the left.
+  * This can be necesary if the user wants to define its own hashes. */
+inline unsigned rotate_left(unsigned n)
+{
+       return (n & 0x80000000U) ? (n << 1 | 0x00000001U) : (n << 1);
+}
+
 /** Compare two pointers (just to establish some sort of canonical order).
  *  @return -1, 0, or 1 */
 template <class T>