| 1 | /* Zero byte detection; indexes. Generic C version. |
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| 2 | Copyright (C) 2023-2024 Free Software Foundation, Inc. |
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| 3 | This file is part of the GNU C Library. |
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| 4 | |
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| 5 | The GNU C Library is free software; you can redistribute it and/or |
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| 6 | modify it under the terms of the GNU Lesser General Public |
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| 7 | License as published by the Free Software Foundation; either |
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| 8 | version 2.1 of the License, or (at your option) any later version. |
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| 9 | |
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| 10 | The GNU C Library is distributed in the hope that it will be useful, |
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| 11 | but WITHOUT ANY WARRANTY; without even the implied warranty of |
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| 12 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
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| 13 | Lesser General Public License for more details. |
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| 14 | |
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| 15 | You should have received a copy of the GNU Lesser General Public |
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| 16 | License along with the GNU C Library; if not, see |
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| 17 | <http://www.gnu.org/licenses/>. */ |
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| 18 | |
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| 19 | #ifndef _STRING_FZI_H |
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| 20 | #define _STRING_FZI_H 1 |
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| 21 | |
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| 22 | #include <limits.h> |
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| 23 | #include <endian.h> |
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| 24 | #include <string-fza.h> |
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| 25 | |
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| 26 | static __always_inline int |
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| 27 | clz (find_t c) |
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| 28 | { |
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| 29 | if (sizeof (find_t) == sizeof (unsigned long)) |
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| 30 | return __builtin_clzl (c); |
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| 31 | else |
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| 32 | return __builtin_clzll (c); |
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| 33 | } |
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| 34 | |
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| 35 | static __always_inline int |
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| 36 | ctz (find_t c) |
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| 37 | { |
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| 38 | if (sizeof (find_t) == sizeof (unsigned long)) |
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| 39 | return __builtin_ctzl (c); |
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| 40 | else |
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| 41 | return __builtin_ctzll (c); |
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| 42 | } |
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| 43 | |
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| 44 | /* A subroutine for the index_zero functions. Given a test word C, return |
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| 45 | the (memory order) index of the first byte (in memory order) that is |
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| 46 | non-zero. */ |
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| 47 | static __always_inline unsigned int |
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| 48 | index_first (find_t c) |
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| 49 | { |
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| 50 | int r; |
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| 51 | if (__BYTE_ORDER == __LITTLE_ENDIAN) |
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| 52 | r = ctz (c); |
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| 53 | else |
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| 54 | r = clz (c); |
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| 55 | return r / CHAR_BIT; |
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| 56 | } |
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| 57 | |
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| 58 | /* Similarly, but return the (memory order) index of the last byte that is |
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| 59 | non-zero. */ |
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| 60 | static __always_inline unsigned int |
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| 61 | index_last (find_t c) |
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| 62 | { |
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| 63 | int r; |
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| 64 | if (__BYTE_ORDER == __LITTLE_ENDIAN) |
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| 65 | r = clz (c); |
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| 66 | else |
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| 67 | r = ctz (c); |
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| 68 | return sizeof (find_t) - 1 - (r / CHAR_BIT); |
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| 69 | } |
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| 70 | |
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| 71 | #endif /* STRING_FZI_H */ |
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| 72 | |
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