X-Git-Url: http://erislabs.net/gitweb/?a=blobdiff_plain;f=lib%2Fbitrotate.h;h=c3a5e1a5d2b92917a3d8f7113e29e0097176e630;hb=c3de829c6f94be07b6104c5403d070791fc516fb;hp=65bf682f9432ebc4772783a3dbe011502224e82d;hpb=b729ee98921bac8c8687a4d1a941aa0567f8196e;p=gnulib.git

diff --git a/lib/bitrotate.h b/lib/bitrotate.h
index 65bf682f9..c3a5e1a5d 100644
--- 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) 2008-2011 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
@@ -28,7 +30,7 @@
 static inline uint64_t
 rotl64 (uint64_t x, int n)
 {
-  return ((x << n) | (x >> (64 - n))) & 0xFFFFFFFFFFFFFFFFULL;
+  return ((x << n) | (x >> (64 - n))) & UINT64_MAX;
 }
 
 /* Given an unsigned 64-bit argument X, return the value corresponding
@@ -37,7 +39,7 @@ rotl64 (uint64_t x, int n)
 static inline uint64_t
 rotr64 (uint64_t x, int n)
 {
-  return ((x >> n) | (x << (64 - n))) & 0xFFFFFFFFFFFFFFFFULL;
+  return ((x >> n) | (x << (64 - n))) & UINT64_MAX;
 }
 #endif
 
@@ -47,7 +49,7 @@ rotr64 (uint64_t x, int n)
 static inline uint32_t
 rotl32 (uint32_t x, int n)
 {
-  return ((x << n) | (x >> (32 - n))) & 0xFFFFFFFF;
+  return ((x << n) | (x >> (32 - n))) & UINT32_MAX;
 }
 
 /* Given an unsigned 32-bit argument X, return the value corresponding
@@ -56,43 +58,69 @@ rotl32 (uint32_t x, int n)
 static inline uint32_t
 rotr32 (uint32_t x, int n)
 {
-  return ((x >> n) | (x << (32 - n))) & 0xFFFFFFFF;
+  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. */
+   15 inclusive, but on most relevant targets N can also be 0 and 16
+   because 'int' is at least 32 bits and the arguments must widen
+   before shifting. */
 static inline uint16_t
 rotl16 (uint16_t x, int n)
 {
-  return ((x << n) | (x >> (16 - n))) & 0xFFFF;
+  return ((x << n) | (x >> (16 - n))) & UINT16_MAX;
 }
 
 /* Given an unsigned 16-bit argument X, return the value corresponding
    to rotating the bits N steps to the right.  N must be in 1 to 15
-   inclusive. */
+   inclusive, but on most relevant targets N can also be 0 and 16
+   because 'int' is at least 32 bits and the arguments must widen
+   before shifting. */
 static inline uint16_t
 rotr16 (uint16_t x, int n)
 {
-  return ((x >> n) | (x << (16 - n))) & 0xFFFF;
+  return ((x >> n) | (x << (16 - n))) & UINT16_MAX;
 }
 
 /* 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. */
+   inclusive, but on most relevant targets N can also be 0 and 8
+   because 'int' is at least 32 bits and the arguments must widen
+   before shifting. */
 static inline uint8_t
 rotl8 (uint8_t x, int n)
 {
-  return ((x << n) | (x >> (8 - n))) & 0xFF;
+  return ((x << n) | (x >> (8 - n))) & UINT8_MAX;
 }
 
 /* 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. */
+   inclusive, but on most relevant targets N can also be 0 and 8
+   because 'int' is at least 32 bits and the arguments must widen
+   before shifting. */
 static inline uint8_t
 rotr8 (uint8_t x, int n)
 {
-  return ((x >> n) | (x << (8 - n))) & 0xFF;
+  return ((x >> n) | (x << (8 - n))) & UINT8_MAX;
 }
 
 #endif /* _GL_BITROTATE_H */