1 | /* Miscellaneous functions used in string implementations. Generic C version. |
2 | Copyright (C) 2023-2024 Free Software Foundation, Inc. |
3 | This file is part of the GNU C Library. |
4 | |
5 | The GNU C Library is free software; you can redistribute it and/or |
6 | modify it under the terms of the GNU Lesser General Public |
7 | License as published by the Free Software Foundation; either |
8 | version 2.1 of the License, or (at your option) any later version. |
9 | |
10 | The GNU C Library is distributed in the hope that it will be useful, |
11 | but WITHOUT ANY WARRANTY; without even the implied warranty of |
12 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
13 | Lesser General Public License for more details. |
14 | |
15 | You should have received a copy of the GNU Lesser General Public |
16 | License along with the GNU C Library; if not, see |
17 | <http://www.gnu.org/licenses/>. */ |
18 | |
19 | #ifndef _STRING_MISC_H |
20 | #define _STRING_MISC_H 1 |
21 | |
22 | #include <limits.h> |
23 | #include <endian.h> |
24 | #include <string-optype.h> |
25 | |
26 | /* Extract the byte at index IDX from word X, with index 0 being the |
27 | least significant byte. */ |
28 | static __always_inline unsigned char |
29 | (op_t x, unsigned int idx) |
30 | { |
31 | if (__BYTE_ORDER == __LITTLE_ENDIAN) |
32 | return x >> (idx * CHAR_BIT); |
33 | else |
34 | return x >> (sizeof (x) - 1 - idx) * CHAR_BIT; |
35 | } |
36 | |
37 | /* Setup an word with each byte being c_in. For instance, on a 64 bits |
38 | machine with input as 0xce the functions returns 0xcececececececece. */ |
39 | static __always_inline op_t |
40 | repeat_bytes (unsigned char c_in) |
41 | { |
42 | return ((op_t)-1 / 0xff) * c_in; |
43 | } |
44 | |
45 | #endif /* _STRING_MISC_H */ |
46 | |