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/* hash-pjw.c -- compute a hash value from a NUL-terminated string.
Copyright (C) 2001, 2003, 2006, 2009-2021 Free Software Foundation, Inc.
This file 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.
This file 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 this program. If not, see <https://www.gnu.org/licenses/>. */
#include <config.h>
#include "hash-pjw.h"
#include <limits.h>
#define SIZE_BITS (sizeof (size_t) * CHAR_BIT)
/* A hash function for NUL-terminated char* strings using
the method described by Bruno Haible.
See https://www.haible.de/bruno/hashfunc.html. */
size_t
hash_pjw (const void *x, size_t tablesize)
{
const char *s;
size_t h = 0;
for (s = x; *s; s++)
h = *s + ((h << 9) | (h >> (SIZE_BITS - 9)));
return h % tablesize;
}
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