mirror of
https://gitlab.freedesktop.org/gstreamer/gstreamer.git
synced 2024-11-03 16:09:39 +00:00
63 lines
1.6 KiB
C
63 lines
1.6 KiB
C
/* GStreamer
|
|
* Copyright (C) 2007 Thomas Vander Stichele <thomas at apestaart dot org>
|
|
*
|
|
* This library is free software; you can redistribute it and/or
|
|
* modify it under the terms of the GNU Library General Public
|
|
* License as published by the Free Software Foundation; either
|
|
* version 2 of the License, or (at your option) any later version.
|
|
*
|
|
* This 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
|
|
* Library General Public License for more details.
|
|
*
|
|
* You should have received a copy of the GNU Library General Public
|
|
* License along with this library; if not, write to the
|
|
* Free Software Foundation, Inc., 59 Temple Place - Suite 330,
|
|
* Boston, MA 02111-1307, USA.
|
|
*/
|
|
|
|
#ifdef HAVE_CONFIG_H
|
|
# include "config.h"
|
|
#endif
|
|
|
|
#include <glib.h>
|
|
|
|
#include "fnv1hash.h"
|
|
|
|
/* This file implements FNV-1 hashing used in the Ogg payload encoders
|
|
* to generate the 24-bit ident value based on the header pages.
|
|
* See http://isthe.com/chongo/tech/comp/fnv/
|
|
*/
|
|
|
|
#define MASK_24 (((guint32) 1 << 24) -1)
|
|
|
|
#define FNV1_HASH_32_INIT ((guint32) 0x811C9DC5L)
|
|
//2166136261L)
|
|
#define FNV1_HASH_32_PRIME 16777619
|
|
|
|
guint32
|
|
fnv1_hash_32_new (void)
|
|
{
|
|
return FNV1_HASH_32_INIT;
|
|
}
|
|
|
|
guint32
|
|
fnv1_hash_32_update (guint32 hash, const guchar * data, guint length)
|
|
{
|
|
guint i;
|
|
const guchar *p = data;
|
|
|
|
for (i = 0; i < length; ++i, ++p) {
|
|
hash *= FNV1_HASH_32_PRIME;
|
|
hash ^= *p;
|
|
}
|
|
|
|
return hash;
|
|
}
|
|
|
|
guint32
|
|
fnv1_hash_32_to_24 (guint32 hash)
|
|
{
|
|
return (hash >> 24) ^ (hash & MASK_24);
|
|
}
|