1 /* bitrotate.h - Rotate bits in integers 2 Copyright (C) 2008-2012 Free Software Foundation, Inc. 3 4 This program is free software: you can redistribute it and/or modify 5 it under the terms of the GNU General Public License as published by 6 the Free Software Foundation; either version 3 of the License, or 7 (at your option) any later version. 8 9 This program is distributed in the hope that it will be useful, 10 but WITHOUT ANY WARRANTY; without even the implied warranty of 11 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 12 GNU General Public License for more details. 13 14 You should have received a copy of the GNU General Public License 15 along with this program. If not, see <http://www.gnu.org/licenses/>. */ 16 17 /* Written by Simon Josefsson <simon (at) josefsson.org>, 2008. */ 18 19 #ifndef _GL_BITROTATE_H 20 #define _GL_BITROTATE_H 21 22 #include <limits.h> 23 #include <stdint.h> 24 #include <sys/types.h> 25 26 _GL_INLINE_HEADER_BEGIN 27 #ifndef BITROTATE_INLINE 28 # define BITROTATE_INLINE _GL_INLINE 29 #endif 30 31 #ifdef UINT64_MAX 32 /* Given an unsigned 64-bit argument X, return the value corresponding 33 to rotating the bits N steps to the left. N must be between 1 and 34 63 inclusive. */ 35 BITROTATE_INLINE uint64_t 36 rotl64 (uint64_t x, int n) 37 { 38 return ((x << n) | (x >> (64 - n))) & UINT64_MAX; 39 } 40 41 /* Given an unsigned 64-bit argument X, return the value corresponding 42 to rotating the bits N steps to the right. N must be between 1 to 43 63 inclusive.*/ 44 BITROTATE_INLINE uint64_t 45 rotr64 (uint64_t x, int n) 46 { 47 return ((x >> n) | (x << (64 - n))) & UINT64_MAX; 48 } 49 #endif 50 51 /* Given an unsigned 32-bit argument X, return the value corresponding 52 to rotating the bits N steps to the left. N must be between 1 and 53 31 inclusive. */ 54 BITROTATE_INLINE uint32_t 55 rotl32 (uint32_t x, int n) 56 { 57 return ((x << n) | (x >> (32 - n))) & UINT32_MAX; 58 } 59 60 /* Given an unsigned 32-bit argument X, return the value corresponding 61 to rotating the bits N steps to the right. N must be between 1 to 62 31 inclusive.*/ 63 BITROTATE_INLINE uint32_t 64 rotr32 (uint32_t x, int n) 65 { 66 return ((x >> n) | (x << (32 - n))) & UINT32_MAX; 67 } 68 69 /* Given a size_t argument X, return the value corresponding 70 to rotating the bits N steps to the left. N must be between 1 and 71 (CHAR_BIT * sizeof (size_t) - 1) inclusive. */ 72 BITROTATE_INLINE size_t 73 rotl_sz (size_t x, int n) 74 { 75 return ((x << n) | (x >> ((CHAR_BIT * sizeof x) - n))) & SIZE_MAX; 76 } 77 78 /* Given a size_t argument X, return the value corresponding 79 to rotating the bits N steps to the right. N must be between 1 to 80 (CHAR_BIT * sizeof (size_t) - 1) inclusive. */ 81 BITROTATE_INLINE size_t 82 rotr_sz (size_t x, int n) 83 { 84 return ((x >> n) | (x << ((CHAR_BIT * sizeof x) - n))) & SIZE_MAX; 85 } 86 87 /* Given an unsigned 16-bit argument X, return the value corresponding 88 to rotating the bits N steps to the left. N must be between 1 to 89 15 inclusive, but on most relevant targets N can also be 0 and 16 90 because 'int' is at least 32 bits and the arguments must widen 91 before shifting. */ 92 BITROTATE_INLINE uint16_t 93 rotl16 (uint16_t x, int n) 94 { 95 return ((x << n) | (x >> (16 - n))) & UINT16_MAX; 96 } 97 98 /* Given an unsigned 16-bit argument X, return the value corresponding 99 to rotating the bits N steps to the right. N must be in 1 to 15 100 inclusive, but on most relevant targets N can also be 0 and 16 101 because 'int' is at least 32 bits and the arguments must widen 102 before shifting. */ 103 BITROTATE_INLINE uint16_t 104 rotr16 (uint16_t x, int n) 105 { 106 return ((x >> n) | (x << (16 - n))) & UINT16_MAX; 107 } 108 109 /* Given an unsigned 8-bit argument X, return the value corresponding 110 to rotating the bits N steps to the left. N must be between 1 to 7 111 inclusive, but on most relevant targets N can also be 0 and 8 112 because 'int' is at least 32 bits and the arguments must widen 113 before shifting. */ 114 BITROTATE_INLINE uint8_t 115 rotl8 (uint8_t x, int n) 116 { 117 return ((x << n) | (x >> (8 - n))) & UINT8_MAX; 118 } 119 120 /* Given an unsigned 8-bit argument X, return the value corresponding 121 to rotating the bits N steps to the right. N must be in 1 to 7 122 inclusive, but on most relevant targets N can also be 0 and 8 123 because 'int' is at least 32 bits and the arguments must widen 124 before shifting. */ 125 BITROTATE_INLINE uint8_t 126 rotr8 (uint8_t x, int n) 127 { 128 return ((x >> n) | (x << (8 - n))) & UINT8_MAX; 129 } 130 131 _GL_INLINE_HEADER_END 132 133 #endif /* _GL_BITROTATE_H */ 134
