| 1 | /* Copyright (C) 1991-2024 Free Software Foundation, Inc. |
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| 2 | This file is part of the GNU C Library. |
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| 3 | |
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| 4 | The GNU C Library is free software; you can redistribute it and/or |
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| 5 | modify it under the terms of the GNU Lesser General Public |
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| 6 | License as published by the Free Software Foundation; either |
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| 7 | version 2.1 of the License, or (at your option) any later version. |
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| 8 | |
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| 9 | The GNU C Library is distributed in the hope that it will be useful, |
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| 10 | but WITHOUT ANY WARRANTY; without even the implied warranty of |
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| 11 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
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| 12 | Lesser General Public License for more details. |
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| 13 | |
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| 14 | You should have received a copy of the GNU Lesser General Public |
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| 15 | License along with the GNU C Library; if not, see |
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| 16 | <https://www.gnu.org/licenses/>. */ |
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| 17 | |
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| 18 | #include <libc-pointer-arith.h> |
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| 19 | #include <string-fzb.h> |
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| 20 | #include <string-fzc.h> |
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| 21 | #include <string-fzi.h> |
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| 22 | #include <string-shift.h> |
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| 23 | #include <string.h> |
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| 24 | |
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| 25 | #ifdef STRLEN |
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| 26 | # define __strlen STRLEN |
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| 27 | #endif |
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| 28 | |
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| 29 | /* Return the length of the null-terminated string STR. Scan for |
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| 30 | the null terminator quickly by testing four bytes at a time. */ |
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| 31 | size_t |
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| 32 | __strlen (const char *str) |
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| 33 | { |
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| 34 | /* Align pointer to sizeof op_t. */ |
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| 35 | const uintptr_t s_int = (uintptr_t) str; |
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| 36 | const op_t *word_ptr = (const op_t*) PTR_ALIGN_DOWN (str, sizeof (op_t)); |
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| 37 | |
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| 38 | op_t word = *word_ptr; |
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| 39 | find_t mask = shift_find (word: find_zero_all (x: word), s: s_int); |
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| 40 | if (mask != 0) |
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| 41 | return index_first (c: mask); |
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| 42 | |
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| 43 | do |
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| 44 | word = *++word_ptr; |
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| 45 | while (! has_zero (x: word)); |
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| 46 | |
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| 47 | return ((const char *) word_ptr) + index_first_zero (x: word) - str; |
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| 48 | } |
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| 49 | #ifndef STRLEN |
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| 50 | weak_alias (__strlen, strlen) |
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| 51 | libc_hidden_builtin_def (strlen) |
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| 52 | #endif |
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| 53 | |
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