bitrotate: Add 8 bit rotate functions.

3 files changed, 21 insertions, 1 deletions

diff --git a/ChangeLog b/ChangeLog
index d085060b00..f741e0afe9 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,5 +1,7 @@
 2008-09-01  Simon Josefsson  <simon@josefsson.org>
 
+	* lib/bitrotate.h (rotl8, rotr8): Add.
+
 	* modules/bitrotate (configure.ac): Need
 	AC_REQUIRE([AC_C_INLINE]).
 	(Description): Mention stdint.h.  Reported by Bruno Haible
diff --git a/lib/bitrotate.h b/lib/bitrotate.h
index 8123a5c7f4..1ac1cff42b 100644
--- a/lib/bitrotate.h
+++ b/lib/bitrotate.h
@@ -57,4 +57,22 @@ rotr16 (uint16_t x, int n)
   return ((x >> n) | (x << (16 - n))) & 0xFFFF;
 }
 
+/* Given an unsigned 8-bit argument X, return the value corresponding
+   to rotating the bits N steps to the left.  N must be between 1 to 7
+   inclusive. */
+static inline uint8_t
+rotl8 (uint8_t x, int n)
+{
+  return ((x << n) | (x >> (8 - n))) & 0xFF;
+}
+
+/* Given an unsigned 8-bit argument X, return the value corresponding
+   to rotating the bits N steps to the right.  N must be in 1 to 7
+   inclusive. */
+static inline uint8_t
+rotr8 (uint8_t x, int n)
+{
+  return ((x >> n) | (x << (8 - n))) & 0xFF;
+}
+
 #endif /* _GL_BITROTATE_H */
diff --git a/modules/bitrotate b/modules/bitrotate
index 13bd97e313..63124a89e0 100644
--- a/modules/bitrotate
+++ b/modules/bitrotate
@@ -1,5 +1,5 @@
 Description:
-Rotate bits in 16 and 32 bit integers.
+Rotate bits in unsigned 8, 16, and 32 bit integers.
 
 Files:
 lib/bitrotate.h