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/* Implements hashing function for string with known length.
Copyright (C) 1996-2024 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 <sys/types.h>
/* We assume to have `size_t' value with at least 32 bits. */
#define HASHWORDBITS 32
/* Defines the so called `hashpjw' function by P.J. Weinberger
[see Aho/Sethi/Ullman, COMPILERS: Principles, Techniques and Tools,
1986, 1987 Bell Telephone Laboratories, Inc.] */
static size_t hash_string (const char *__str_param, size_t __len);
static inline size_t
hash_string (const char *str_param, size_t len)
{
size_t hval, g;
const char *end_str = str_param + len;
/* Compute the hash value for the given string. */
hval = len;
while (str_param != end_str)
{
hval <<= 4;
hval += (size_t) *str_param++;
g = hval & ((size_t) 0xf << (HASHWORDBITS - 4));
if (g != 0)
{
hval ^= g >> (HASHWORDBITS - 8);
hval ^= g;
}
}
return hval;
}
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