1 | /* bitrotate.h - Rotate bits in integers |
2 | Copyright (C) 2008-2019 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 <https://www.gnu.org/licenses/>. */ |
16 | |
17 | /* Written by Simon Josefsson <simon@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 | #ifndef _GL_INLINE_HEADER_BEGIN |
27 | #error "Please include config.h first." |
28 | #endif |
29 | _GL_INLINE_HEADER_BEGIN |
30 | #ifndef BITROTATE_INLINE |
31 | # define BITROTATE_INLINE _GL_INLINE |
32 | #endif |
33 | |
34 | #ifdef UINT64_MAX |
35 | /* Given an unsigned 64-bit argument X, return the value corresponding |
36 | to rotating the bits N steps to the left. N must be between 1 and |
37 | 63 inclusive. */ |
38 | BITROTATE_INLINE uint64_t |
39 | rotl64 (uint64_t x, int n) |
40 | { |
41 | return ((x << n) | (x >> (64 - n))) & UINT64_MAX; |
42 | } |
43 | |
44 | /* Given an unsigned 64-bit argument X, return the value corresponding |
45 | to rotating the bits N steps to the right. N must be between 1 to |
46 | 63 inclusive.*/ |
47 | BITROTATE_INLINE uint64_t |
48 | rotr64 (uint64_t x, int n) |
49 | { |
50 | return ((x >> n) | (x << (64 - n))) & UINT64_MAX; |
51 | } |
52 | #endif |
53 | |
54 | /* Given an unsigned 32-bit argument X, return the value corresponding |
55 | to rotating the bits N steps to the left. N must be between 1 and |
56 | 31 inclusive. */ |
57 | BITROTATE_INLINE uint32_t |
58 | rotl32 (uint32_t x, int n) |
59 | { |
60 | return ((x << n) | (x >> (32 - n))) & UINT32_MAX; |
61 | } |
62 | |
63 | /* Given an unsigned 32-bit argument X, return the value corresponding |
64 | to rotating the bits N steps to the right. N must be between 1 to |
65 | 31 inclusive.*/ |
66 | BITROTATE_INLINE uint32_t |
67 | rotr32 (uint32_t x, int n) |
68 | { |
69 | return ((x >> n) | (x << (32 - n))) & UINT32_MAX; |
70 | } |
71 | |
72 | /* Given a size_t argument X, return the value corresponding |
73 | to rotating the bits N steps to the left. N must be between 1 and |
74 | (CHAR_BIT * sizeof (size_t) - 1) inclusive. */ |
75 | BITROTATE_INLINE size_t |
76 | rotl_sz (size_t x, int n) |
77 | { |
78 | return ((x << n) | (x >> ((CHAR_BIT * sizeof x) - n))) & SIZE_MAX; |
79 | } |
80 | |
81 | /* Given a size_t argument X, return the value corresponding |
82 | to rotating the bits N steps to the right. N must be between 1 to |
83 | (CHAR_BIT * sizeof (size_t) - 1) inclusive. */ |
84 | BITROTATE_INLINE size_t |
85 | rotr_sz (size_t x, int n) |
86 | { |
87 | return ((x >> n) | (x << ((CHAR_BIT * sizeof x) - n))) & SIZE_MAX; |
88 | } |
89 | |
90 | /* Given an unsigned 16-bit argument X, return the value corresponding |
91 | to rotating the bits N steps to the left. N must be between 1 to |
92 | 15 inclusive, but on most relevant targets N can also be 0 and 16 |
93 | because 'int' is at least 32 bits and the arguments must widen |
94 | before shifting. */ |
95 | BITROTATE_INLINE uint16_t |
96 | rotl16 (uint16_t x, int n) |
97 | { |
98 | return (((unsigned int) x << n) | ((unsigned int) x >> (16 - n))) |
99 | & UINT16_MAX; |
100 | } |
101 | |
102 | /* Given an unsigned 16-bit argument X, return the value corresponding |
103 | to rotating the bits N steps to the right. N must be in 1 to 15 |
104 | inclusive, but on most relevant targets N can also be 0 and 16 |
105 | because 'int' is at least 32 bits and the arguments must widen |
106 | before shifting. */ |
107 | BITROTATE_INLINE uint16_t |
108 | rotr16 (uint16_t x, int n) |
109 | { |
110 | return (((unsigned int) x >> n) | ((unsigned int) x << (16 - n))) |
111 | & UINT16_MAX; |
112 | } |
113 | |
114 | /* Given an unsigned 8-bit argument X, return the value corresponding |
115 | to rotating the bits N steps to the left. N must be between 1 to 7 |
116 | inclusive, but on most relevant targets N can also be 0 and 8 |
117 | because 'int' is at least 32 bits and the arguments must widen |
118 | before shifting. */ |
119 | BITROTATE_INLINE uint8_t |
120 | rotl8 (uint8_t x, int n) |
121 | { |
122 | return (((unsigned int) x << n) | ((unsigned int) x >> (8 - n))) & UINT8_MAX; |
123 | } |
124 | |
125 | /* Given an unsigned 8-bit argument X, return the value corresponding |
126 | to rotating the bits N steps to the right. N must be in 1 to 7 |
127 | inclusive, but on most relevant targets N can also be 0 and 8 |
128 | because 'int' is at least 32 bits and the arguments must widen |
129 | before shifting. */ |
130 | BITROTATE_INLINE uint8_t |
131 | rotr8 (uint8_t x, int n) |
132 | { |
133 | return (((unsigned int) x >> n) | ((unsigned int) x << (8 - n))) & UINT8_MAX; |
134 | } |
135 | |
136 | _GL_INLINE_HEADER_END |
137 | |
138 | #endif /* _GL_BITROTATE_H */ |
139 | |