Mercurial > gnulib
view lib/hash-pjw-bare.c @ 40086:d6de7c427079
stdopen: modernize and simplify
* lib/stdopen.c: Update copyright date
Do not include sys/types.h; no longer needed these days.
(stdopen): Use C99-style decl in loop. Return int errno
value, rather than just a bool. Do not worry about fd mismatches,
since the caller cares only if 0, 1, 2 are occupied.
* lib/stdopen.h: No need to include <stdbool.h>.
* m4/stdopen.m4: Remove.
* modules/stdopen: New file.
author | Paul Eggert <eggert@cs.ucla.edu> |
---|---|
date | Sat, 05 Jan 2019 18:02:32 -0800 |
parents | b06060465f09 |
children |
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/* hash-pjw-bare.c -- compute a hash value from a provided buffer. Copyright (C) 2012-2019 Free Software Foundation, Inc. This program 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 3 of the License, or (at your option) any later version. This program 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-bare.h" #include <limits.h> #define SIZE_BITS (sizeof (size_t) * CHAR_BIT) /* Return a hash of the N bytes of X using the method described by Bruno Haible in https://www.haible.de/bruno/hashfunc.html. Note that while many hash functions reduce their result via modulo to a 0..table_size-1 range, this function does not do that. */ size_t hash_pjw_bare (const void *x, size_t n) { const unsigned char *s = x; size_t h = 0; unsigned i; for (i = 0; i < n; i++) h = s[i] + ((h << 9) | (h >> (SIZE_BITS - 9))); return h; }