| 1 | /* Copyright (C) 1991-2024 Free Software Foundation, Inc. |
|---|---|
| 2 | This file is part of the GNU C Library. |
| 3 | |
| 4 | The GNU C Library is free software; you can redistribute it and/or |
| 5 | modify it under the terms of the GNU Lesser General Public |
| 6 | License as published by the Free Software Foundation; either |
| 7 | version 2.1 of the License, or (at your option) any later version. |
| 8 | |
| 9 | The GNU C Library 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 GNU |
| 12 | Lesser General Public License for more details. |
| 13 | |
| 14 | You should have received a copy of the GNU Lesser General Public |
| 15 | License along with the GNU C Library; if not, see |
| 16 | <https://www.gnu.org/licenses/>. */ |
| 17 | |
| 18 | #include <libc-pointer-arith.h> |
| 19 | #include <string-fzb.h> |
| 20 | #include <string-fzc.h> |
| 21 | #include <string-fzi.h> |
| 22 | #include <string-shift.h> |
| 23 | #include <string.h> |
| 24 | |
| 25 | #ifdef STRLEN |
| 26 | # define __strlen STRLEN |
| 27 | #endif |
| 28 | |
| 29 | /* Return the length of the null-terminated string STR. Scan for |
| 30 | the null terminator quickly by testing four bytes at a time. */ |
| 31 | size_t |
| 32 | __strlen (const char *str) |
| 33 | { |
| 34 | /* Align pointer to sizeof op_t. */ |
| 35 | const uintptr_t s_int = (uintptr_t) str; |
| 36 | const op_t *word_ptr = (const op_t*) PTR_ALIGN_DOWN (str, sizeof (op_t)); |
| 37 | |
| 38 | op_t word = *word_ptr; |
| 39 | find_t mask = shift_find (word: find_zero_all (x: word), s: s_int); |
| 40 | if (mask != 0) |
| 41 | return index_first (c: mask); |
| 42 | |
| 43 | do |
| 44 | word = *++word_ptr; |
| 45 | while (! has_zero (x: word)); |
| 46 | |
| 47 | return ((const char *) word_ptr) + index_first_zero (x: word) - str; |
| 48 | } |
| 49 | #ifndef STRLEN |
| 50 | weak_alias (__strlen, strlen) |
| 51 | libc_hidden_builtin_def (strlen) |
| 52 | #endif |
| 53 |