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/* Zero byte detection; indexes. Generic C version.
Copyright (C) 2023-2025 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
<http://www.gnu.org/licenses/>. */
#ifndef _STRING_FZI_H
#define _STRING_FZI_H 1
#include <limits.h>
#include <endian.h>
#include <string-fza.h>
static __always_inline int
clz (find_t c)
{
if (sizeof (find_t) == sizeof (unsigned long))
return __builtin_clzl (c);
else
return __builtin_clzll (c);
}
static __always_inline int
ctz (find_t c)
{
if (sizeof (find_t) == sizeof (unsigned long))
return __builtin_ctzl (c);
else
return __builtin_ctzll (c);
}
/* A subroutine for the index_zero functions. Given a test word C, return
the (memory order) index of the first byte (in memory order) that is
non-zero. */
static __always_inline unsigned int
index_first (find_t c)
{
int r;
if (__BYTE_ORDER == __LITTLE_ENDIAN)
r = ctz (c);
else
r = clz (c);
return r / CHAR_BIT;
}
/* Similarly, but return the (memory order) index of the last byte that is
non-zero. */
static __always_inline unsigned int
index_last (find_t c)
{
int r;
if (__BYTE_ORDER == __LITTLE_ENDIAN)
r = clz (c);
else
r = ctz (c);
return sizeof (find_t) - 1 - (r / CHAR_BIT);
}
#endif /* STRING_FZI_H */
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