mirror of
https://sourceware.org/git/glibc.git
synced 2024-11-23 01:33:36 +08:00
53 lines
1.6 KiB
C
53 lines
1.6 KiB
C
/* Copyright (C) 1991-2024 Free Software Foundation, Inc.
|
|
This file is part of the GNU C Library.
|
|
|
|
The GNU C Library is free software; you can redistribute it and/or
|
|
modify it under the terms of the GNU Lesser General Public
|
|
License as published by the Free Software Foundation; either
|
|
version 2.1 of the License, or (at your option) any later version.
|
|
|
|
The GNU C Library is distributed in the hope that it will be useful,
|
|
but WITHOUT ANY WARRANTY; without even the implied warranty of
|
|
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
|
|
Lesser General Public License for more details.
|
|
|
|
You should have received a copy of the GNU Lesser General Public
|
|
License along with the GNU C Library; if not, see
|
|
<https://www.gnu.org/licenses/>. */
|
|
|
|
#include <libc-pointer-arith.h>
|
|
#include <string-fzb.h>
|
|
#include <string-fzc.h>
|
|
#include <string-fzi.h>
|
|
#include <string-shift.h>
|
|
#include <string.h>
|
|
|
|
#ifdef STRLEN
|
|
# define __strlen STRLEN
|
|
#endif
|
|
|
|
/* Return the length of the null-terminated string STR. Scan for
|
|
the null terminator quickly by testing four bytes at a time. */
|
|
size_t
|
|
__strlen (const char *str)
|
|
{
|
|
/* Align pointer to sizeof op_t. */
|
|
const uintptr_t s_int = (uintptr_t) str;
|
|
const op_t *word_ptr = (const op_t*) PTR_ALIGN_DOWN (str, sizeof (op_t));
|
|
|
|
op_t word = *word_ptr;
|
|
find_t mask = shift_find (find_zero_all (word), s_int);
|
|
if (mask != 0)
|
|
return index_first (mask);
|
|
|
|
do
|
|
word = *++word_ptr;
|
|
while (! has_zero (word));
|
|
|
|
return ((const char *) word_ptr) + index_first_zero (word) - str;
|
|
}
|
|
#ifndef STRLEN
|
|
weak_alias (__strlen, strlen)
|
|
libc_hidden_builtin_def (strlen)
|
|
#endif
|