hash: make rotation more obvious

[gnulib.git] / lib / bitrotate.h

diff --git a/lib/bitrotate.h b/lib/bitrotate.h
index d4911d0..63f5d56 100644 (file)
--- a/lib/bitrotate.h
+++ b/lib/bitrotate.h
@@ -1,5 +1,5 @@
 /* bitrotate.h - Rotate bits in integers
-   Copyright (C) 2008 Free Software Foundation, Inc.
+   Copyright (C) 2008, 2009 Free Software Foundation, Inc.
 
    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
@@ -19,7 +19,9 @@
 #ifndef _GL_BITROTATE_H
 #define _GL_BITROTATE_H
 
+#include <limits.h>
 #include <stdint.h>
+#include <sys/types.h>
 
 #ifdef UINT64_MAX
 /* Given an unsigned 64-bit argument X, return the value corresponding
@@ -59,6 +61,24 @@ rotr32 (uint32_t x, int n)
   return ((x >> n) | (x << (32 - n))) & UINT32_MAX;
 }
 
+/* Given a size_t argument X, return the value corresponding
+   to rotating the bits N steps to the left.  N must be between 1 and
+   (CHAR_BIT * sizeof (size_t) - 1) inclusive.  */
+static inline size_t
+rotl_sz (size_t x, int n)
+{
+  return ((x << n) | (x >> ((CHAR_BIT * sizeof x) - n))) & SIZE_MAX;
+}
+
+/* Given a size_t argument X, return the value corresponding
+   to rotating the bits N steps to the right.  N must be between 1 to
+   (CHAR_BIT * sizeof (size_t) - 1) inclusive.  */
+static inline size_t
+rotr_sz (size_t x, int n)
+{
+  return ((x >> n) | (x << ((CHAR_BIT * sizeof x) - n))) & SIZE_MAX;
+}
+
 /* Given an unsigned 16-bit argument X, return the value corresponding
    to rotating the bits N steps to the left.  N must be between 1 to
    15 inclusive, but on most relevant targets N can also be 0 and 16