1 files changed, 138 insertions, 0 deletions
diff --git a/src/gl/bitrotate.h b/src/gl/bitrotate.h
new file mode 100644
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--- /dev/null
+++ b/src/gl/bitrotate.h
@@ -0,0 +1,138 @@
+/* bitrotate.h - Rotate bits in integers
+   Copyright (C) 2008-2021 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
+   the Free Software Foundation; either version 3 of the License, or
+   (at your option) any later version.
+
+   This program is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU General Public License for more details.
+
+   You should have received a copy of the GNU General Public License
+   along with this program.  If not, see <https://www.gnu.org/licenses/>.  */
+
+/* Written by Simon Josefsson <simon@josefsson.org>, 2008. */
+
+#ifndef _GL_BITROTATE_H
+#define _GL_BITROTATE_H
+
+#include <limits.h>
+#include <stdint.h>
+#include <sys/types.h>
+
+#ifndef _GL_INLINE_HEADER_BEGIN
+ #error "Please include config.h first."
+#endif
+_GL_INLINE_HEADER_BEGIN
+#ifndef BITROTATE_INLINE
+# define BITROTATE_INLINE _GL_INLINE
+#endif
+
+#ifdef UINT64_MAX
+/* Given an unsigned 64-bit argument X, return the value corresponding
+   to rotating the bits N steps to the left.  N must be between 1 and
+   63 inclusive. */
+BITROTATE_INLINE uint64_t
+rotl64 (uint64_t x, int n)
+{
+  return ((x << n) | (x >> (64 - n))) & UINT64_MAX;
+}
+
+/* Given an unsigned 64-bit argument X, return the value corresponding
+   to rotating the bits N steps to the right.  N must be between 1 to
+   63 inclusive.*/
+BITROTATE_INLINE uint64_t
+rotr64 (uint64_t x, int n)
+{
+  return ((x >> n) | (x << (64 - n))) & UINT64_MAX;
+}
+#endif
+
+/* Given an unsigned 32-bit argument X, return the value corresponding
+   to rotating the bits N steps to the left.  N must be between 1 and
+   31 inclusive. */
+BITROTATE_INLINE uint32_t
+rotl32 (uint32_t x, int n)
+{
+  return ((x << n) | (x >> (32 - n))) & UINT32_MAX;
+}
+
+/* Given an unsigned 32-bit argument X, return the value corresponding
+   to rotating the bits N steps to the right.  N must be between 1 to
+   31 inclusive.*/
+BITROTATE_INLINE uint32_t
+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.  */
+BITROTATE_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.  */
+BITROTATE_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
+   because 'int' is at least 32 bits and the arguments must widen
+   before shifting. */
+BITROTATE_INLINE uint16_t
+rotl16 (uint16_t x, int n)
+{
+  return (((unsigned int) x << n) | ((unsigned int) 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, 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. */
+BITROTATE_INLINE uint16_t
+rotr16 (uint16_t x, int n)
+{
+  return (((unsigned int) x >> n) | ((unsigned int) 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, 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. */
+BITROTATE_INLINE uint8_t
+rotl8 (uint8_t x, int n)
+{
+  return (((unsigned int) x << n) | ((unsigned int) 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, 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. */
+BITROTATE_INLINE uint8_t
+rotr8 (uint8_t x, int n)
+{
+  return (((unsigned int) x >> n) | ((unsigned int) x << (8 - n))) & UINT8_MAX;
+}
+
+_GL_INLINE_HEADER_END
+
+#endif /* _GL_BITROTATE_H */