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+/* hash-pjw.c -- compute a hash value from a NUL-terminated string.
+
+ Copyright (C) 2001, 2003, 2006, 2009-2022 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;
+}