From 5e03c718f4e7ff13cb6834eda737c269ebed02ad Mon Sep 17 00:00:00 2001 From: Daniel Baumann Date: Sun, 7 Apr 2024 19:04:52 +0200 Subject: Adding upstream version 1.21.3. Signed-off-by: Daniel Baumann --- lib/hash-pjw.c | 40 ++++++++++++++++++++++++++++++++++++++++ 1 file changed, 40 insertions(+) create mode 100644 lib/hash-pjw.c (limited to 'lib/hash-pjw.c') diff --git a/lib/hash-pjw.c b/lib/hash-pjw.c new file mode 100644 index 0000000..8ba139d --- /dev/null +++ b/lib/hash-pjw.c @@ -0,0 +1,40 @@ +/* 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 . */ + +#include + +#include "hash-pjw.h" + +#include + +#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; +} -- cgit v1.2.3