glibc/sysdeps/generic/string-misc.h

46 lines
1.5 KiB
C

/* Miscellaneous functions used in string implementations. 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_MISC_H
#define _STRING_MISC_H 1
#include <limits.h>
#include <endian.h>
#include <string-optype.h>
/* Extract the byte at index IDX from word X, with index 0 being the
least significant byte. */
static __always_inline unsigned char
extractbyte (op_t x, unsigned int idx)
{
if (__BYTE_ORDER == __LITTLE_ENDIAN)
return x >> (idx * CHAR_BIT);
else
return x >> (sizeof (x) - 1 - idx) * CHAR_BIT;
}
/* Setup an word with each byte being c_in. For instance, on a 64 bits
machine with input as 0xce the functions returns 0xcececececececece. */
static __always_inline op_t
repeat_bytes (unsigned char c_in)
{
return ((op_t)-1 / 0xff) * c_in;
}
#endif /* _STRING_MISC_H */