gstreamer/gst/rtp/fnv1hash.c
Thomas Vander Stichele 2fc868841f gst/rtp/Makefile.am: gst/rtp/fnv1hash.c (MASK_24, FNV1_HASH_32_INIT, FNV1_HASH_32_PRIME, fnv1_hash_32_new, fnv1_hash_...
Original commit message from CVS:
* gst/rtp/Makefile.am:
* gst/rtp/fnv1hash.c (MASK_24, FNV1_HASH_32_INIT, FNV1_HASH_32_PRIME,
fnv1_hash_32_new, fnv1_hash_32_update, fnv1_hash_32_to_24):
* gst/rtp/fnv1hash.h (__GST_FNV1_HASH_H__):
Add a simple hashing implementation that we can use to generate
a 24-bit ident value based on the codebooks for vorbis and theora.
* gst/rtp/gstrtptheorapay.c (gst_rtp_theora_pay_finish_headers,
gst_rtp_theora_pay_handle_buffer):
* gst/rtp/gstrtpvorbisdepay.c
(gst_rtp_vorbis_depay_parse_configuration,
gst_rtp_vorbis_depay_switch_codebook, gst_rtp_vorbis_depay_process):
* gst/rtp/gstrtpvorbispay.c (gst_rtp_vorbis_pay_reset_packet,
gst_rtp_vorbis_pay_init_packet, gst_rtp_vorbis_pay_flush_packet,
gst_rtp_vorbis_pay_finish_headers, gst_rtp_vorbis_pay_handle_buffer):
Use the hashing function, ensuring that the same codebooks result
in the same ident and thus the same SDP description.
Various log fixes/changes.
2007-04-12 11:41:11 +00:00

61 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>
/* 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);
}