From 64c0c13e6e08c51e92504631468db864f553d9b5 Mon Sep 17 00:00:00 2001 From: Bastien Montagne Date: Fri, 14 Nov 2014 11:00:10 +0100 Subject: Add Murmur2A hashing feature to BLI Murmur2a is a very fast hashing function generation int32 hashes. It also features a very good distribution of generated hashes. However, it is not endianness-agnostic, meaning it will usually generate different hashes for a same key on big- and little-endian architectures. Consequently, **it shall not be used to generate persistent hashes** (never store them in .blend file e.g.). This implementation supports incremental hashing, and is a direct adaptation of reference implementation (in c++): https://smhasher.googlecode.com/svn-history/r130/trunk/MurmurHash2.cpp That cpp code was also used to generate reference values in gtests file. Reviewers: sergey, campbellbarton Reviewed By: campbellbarton Projects: #bf_blender Differential Revision: https://developer.blender.org/D892 --- source/blender/blenlib/BLI_hash_mm2a.h | 45 ++++++++++++++++++++++++++++++++++ 1 file changed, 45 insertions(+) create mode 100644 source/blender/blenlib/BLI_hash_mm2a.h (limited to 'source/blender/blenlib/BLI_hash_mm2a.h') diff --git a/source/blender/blenlib/BLI_hash_mm2a.h b/source/blender/blenlib/BLI_hash_mm2a.h new file mode 100644 index 00000000000..503eb5e96d9 --- /dev/null +++ b/source/blender/blenlib/BLI_hash_mm2a.h @@ -0,0 +1,45 @@ +/* + * ***** BEGIN GPL LICENSE BLOCK ***** + * + * This program is free software; you can redistribute it and/or + * modify it under the terms of the GNU General Public License + * as published by the Free Software Foundation; either version 2 + * 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 General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program; if not, write to the Free Software Foundation, + * Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA. + * + * ***** END GPL LICENSE BLOCK ***** + */ + +#ifndef __BLI_MM2A_H__ +#define __BLI_MM2A_H__ + +/** \file BLI_hash_mm2a.h + * \ingroup bli + */ + +#include "BLI_sys_types.h" + +typedef struct BLI_HashMurmur2A { + uint32_t hash; + uint32_t tail; + uint32_t count; + uint32_t size; +} BLI_HashMurmur2A; + +void BLI_hash_mm2a_init(BLI_HashMurmur2A *mm2, uint32_t seed); + +void BLI_hash_mm2a_add(BLI_HashMurmur2A *mm2, const unsigned char *data, size_t len); + +void BLI_hash_mm2a_add_int(BLI_HashMurmur2A *mm2, int data); + +uint32_t BLI_hash_mm2a_end(BLI_HashMurmur2A *mm2); + +#endif /* __BLI_MM2A_H__ */ -- cgit v1.2.3