glibc/sysdeps/generic/string-fzc.h

88 lines
2.4 KiB
C

/* Zero byte detection; indexes. Generic C version.
Copyright (C) 2023-2024 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
<http://www.gnu.org/licenses/>. */
#ifndef _STRING_FZC_H
#define _STRING_FZC_H 1
#include <endian.h>
#include <string-fza.h>
#include <string-fzi.h>
/* Given a word X that is known to contain a zero byte, return the index of
the first such within the word in memory order. */
static __always_inline unsigned int
index_first_zero (op_t x)
{
if (__BYTE_ORDER == __LITTLE_ENDIAN)
x = find_zero_low (x);
else
x = find_zero_all (x);
return index_first (x);
}
/* Similarly, but perform the search for byte equality between X1 and X2. */
static __always_inline unsigned int
index_first_eq (op_t x1, op_t x2)
{
if (__BYTE_ORDER == __LITTLE_ENDIAN)
x1 = find_eq_low (x1, x2);
else
x1 = find_eq_all (x1, x2);
return index_first (x1);
}
/* Similarly, but perform the search for zero within X1 or equality between
X1 and X2. */
static __always_inline unsigned int
index_first_zero_eq (op_t x1, op_t x2)
{
if (__BYTE_ORDER == __LITTLE_ENDIAN)
x1 = find_zero_eq_low (x1, x2);
else
x1 = find_zero_eq_all (x1, x2);
return index_first (x1);
}
/* Similarly, but perform the search for zero within X1 or inequality between
X1 and X2. */
static __always_inline unsigned int
index_first_zero_ne (op_t x1, op_t x2)
{
return index_first (find_zero_ne_all (x1, x2));
}
/* Similarly, but search for the last zero within X. */
static __always_inline unsigned int
index_last_zero (op_t x)
{
if (__BYTE_ORDER == __LITTLE_ENDIAN)
x = find_zero_all (x);
else
x = find_zero_low (x);
return index_last (x);
}
static __always_inline unsigned int
index_last_eq (op_t x1, op_t x2)
{
return index_last_zero (x1 ^ x2);
}
#endif /* STRING_FZC_H */