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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
This commit is contained in:
Bastien Montagne 2014-11-14 11:00:10 +01:00
parent c8a9764987
commit 64c0c13e6e
9 changed files with 238 additions and 9 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

7
source/blender/blenlib/BLI_md5.h → source/blender/blenlib/BLI_hash_md5.h
View File

@ -19,9 +19,9 @@
*/
#ifndef __BLI_MD5_H__
#define __BLI_MD5_H__
#define __BLI_MD5_H__
/** \file BLI_md5.h
/** \file BLI_hash_md5.h
* \ingroup bli
*/
@ -43,5 +43,4 @@ int md5_stream(FILE *stream, void *resblock);
char *md5_to_hexdigest(void *resblock, char r_hex_digest[33]);
#endif
#endif /* __BLI_MD5_H__ */

45
source/blender/blenlib/BLI_hash_mm2a.h Normal file
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@ -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__ */

6
source/blender/blenlib/CMakeLists.txt
View File

@ -65,6 +65,8 @@ set(SRC
intern/freetypefont.c
intern/graph.c
intern/gsqueue.c
intern/hash_md5.c
intern/hash_mm2a.c
intern/jitter.c
intern/lasso.c
intern/listbase.c
@ -80,7 +82,6 @@ set(SRC
intern/math_rotation.c
intern/math_vector.c
intern/math_vector_inline.c
intern/md5.c
intern/noise.c
intern/path_util.c
intern/polyfill2d.c
@ -134,6 +135,8 @@ set(SRC
BLI_ghash.h
BLI_graph.h
BLI_gsqueue.h
BLI_hash_md5.h
BLI_hash_mm2a.h
BLI_heap.h
BLI_jitter.h
BLI_kdopbvh.h
@ -153,7 +156,6 @@ set(SRC
BLI_math_matrix.h
BLI_math_rotation.h
BLI_math_vector.h
BLI_md5.h
BLI_memarena.h
BLI_mempool.h
BLI_noise.h

2
source/blender/blenlib/intern/md5.c → source/blender/blenlib/intern/hash_md5.c
View File

@ -29,7 +29,7 @@
* according to the definition of MD5 in RFC 1321 from April 1992.
*/
#include "BLI_md5.h" /* own include */
#include "BLI_hash_md5.h" /* own include */
#include <stdlib.h>
#include <string.h>

107
source/blender/blenlib/intern/hash_mm2a.c Normal file
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@ -0,0 +1,107 @@
/*
* ***** 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 *****
*
* Copyright (C) 2014 Blender Foundation.
*
*/
/** \file blender/blenlib/intern/hash_mm2a.c
* \ingroup bli
*
* Functions to compute Murmur2A hash key.
*
* A very fast hash generating int32 result, with few collisions and good repartition.
*
* See also:
* reference implementation: https://smhasher.googlecode.com/svn-history/r130/trunk/MurmurHash2.cpp
* and http://programmers.stackexchange.com/questions/49550/which-hashing-algorithm-is-best-for-uniqueness-and-speed
*
* \warning Do not store that hash in files or such, it is not endian-agnostic, so you should only use it
* for temporary data.
*/
#include "BLI_hash_mm2a.h" /* own include */
/* Helpers. */
#define MM2A_M 0x5bd1e995
#define MM2A_MIX(h, k) \
{ \
(k) *= MM2A_M; \
(k) ^= (k) >> 24; \
(k) *= MM2A_M; \
(h) = ((h) * MM2A_M) ^ (k); \
} (void)0
static void mm2a_mix_tail(BLI_HashMurmur2A *mm2, const unsigned char **data, size_t *len)
{
while (*len && ((*len < 4) || mm2->count)) {
mm2->tail |= (uint32_t)(**data) << (mm2->count * 8);
mm2->count++;
(*len)--;
(*data)++;
if (mm2->count == 4) {
MM2A_MIX(mm2->hash, mm2->tail);
mm2->tail = 0;
mm2->count = 0;
}
}
}
void BLI_hash_mm2a_init(BLI_HashMurmur2A *mm2, uint32_t seed)
{
mm2->hash = seed;
mm2->tail = 0;
mm2->count = 0;
mm2->size = 0;
}
void BLI_hash_mm2a_add(BLI_HashMurmur2A *mm2, const unsigned char *data, size_t len)
{
mm2->size += (uint32_t)len;
mm2a_mix_tail(mm2, &data, &len);
for (; len >= 4; data += 4, len -= 4) {
uint32_t k = *(uint32_t *)data;
MM2A_MIX(mm2->hash, k);
}
mm2a_mix_tail(mm2, &data, &len);
}
void BLI_hash_mm2a_add_int(BLI_HashMurmur2A *mm2, int data)
{
BLI_hash_mm2a_add(mm2, (const unsigned char *)&data, sizeof(data));
}
uint32_t BLI_hash_mm2a_end(BLI_HashMurmur2A *mm2)
{
MM2A_MIX(mm2->hash, mm2->tail);
MM2A_MIX(mm2->hash, mm2->size);
mm2->hash ^= mm2->hash >> 13;
mm2->hash *= MM2A_M;
mm2->hash ^= mm2->hash >> 15;
return mm2->hash;
}

2
source/blender/imbuf/intern/thumbs.c
View File

@ -35,7 +35,7 @@
#include "BLI_string.h"
#include "BLI_path_util.h"
#include "BLI_fileops.h"
#include "BLI_md5.h"
#include "BLI_hash_md5.h"
#include "BLI_system.h"
#include BLI_SYSTEM_PID_H

2
source/blender/render/intern/source/render_result.c
View File

@ -37,7 +37,7 @@
#include "BLI_utildefines.h"
#include "BLI_listbase.h"
#include "BLI_md5.h"
#include "BLI_hash_md5.h"
#include "BLI_path_util.h"
#include "BLI_rect.h"
#include "BLI_string.h"

75
tests/gtests/blenlib/BLI_hash_mm2a_test.cc Normal file
View File

@ -0,0 +1,75 @@
/* Apache License, Version 2.0 */
#include "testing/testing.h"
extern "C" {
#include "BLI_hash_mm2a.h"
}
/* Note: Reference results are taken from reference implementation (cpp code, CMurmurHash2A variant):
* https://smhasher.googlecode.com/svn-history/r130/trunk/MurmurHash2.cpp
*/
TEST(hash_mm2a, MM2ABasic)
{
BLI_HashMurmur2A mm2;
const char *data = "Blender";
BLI_hash_mm2a_init(&mm2, 0);
BLI_hash_mm2a_add(&mm2, (const unsigned char *)data, strlen(data));
#ifdef __LITTLE_ENDIAN__
EXPECT_EQ(1633988145, BLI_hash_mm2a_end(&mm2));
#else
EXPECT_EQ(959283772, BLI_hash_mm2a_end(&mm2));
#endif
}
TEST(hash_mm2a, MM2AConcatenateStrings)
{
BLI_HashMurmur2A mm2;
uint32_t hash;
const char *data1 = "Blender";
const char *data2 = " is ";
const char *data3 = "FaNtAsTiC";
const char *data123 = "Blender is FaNtAsTiC";
BLI_hash_mm2a_init(&mm2, 0);
BLI_hash_mm2a_add(&mm2, (const unsigned char *)data1, strlen(data1));
BLI_hash_mm2a_add(&mm2, (const unsigned char *)data2, strlen(data2));
BLI_hash_mm2a_add(&mm2, (const unsigned char *)data3, strlen(data3));
hash = BLI_hash_mm2a_end(&mm2);
BLI_hash_mm2a_init(&mm2, 0);
BLI_hash_mm2a_add(&mm2, (const unsigned char *)data123, strlen(data123));
#ifdef __LITTLE_ENDIAN__
EXPECT_EQ(1545105348, hash);
#else
EXPECT_EQ(2604964730, hash);
#endif
EXPECT_EQ(hash, BLI_hash_mm2a_end(&mm2));
}
TEST(hash_mm2a, MM2AIntegers)
{
BLI_HashMurmur2A mm2;
uint32_t hash;
const int ints[4] = {1, 2, 3, 4};
BLI_hash_mm2a_init(&mm2, 0);
BLI_hash_mm2a_add_int(&mm2, ints[0]);
BLI_hash_mm2a_add_int(&mm2, ints[1]);
BLI_hash_mm2a_add_int(&mm2, ints[2]);
BLI_hash_mm2a_add_int(&mm2, ints[3]);
hash = BLI_hash_mm2a_end(&mm2);
BLI_hash_mm2a_init(&mm2, 0);
BLI_hash_mm2a_add(&mm2, (const unsigned char *)ints, sizeof(ints));
/* Yes, same hash here on little and big endian. */
#ifdef __LITTLE_ENDIAN__
EXPECT_EQ(405493096, hash);
#else
EXPECT_EQ(405493096, hash);
#endif
EXPECT_EQ(hash, BLI_hash_mm2a_end(&mm2));
}

1
tests/gtests/blenlib/CMakeLists.txt
View File

@ -42,3 +42,4 @@ BLENDER_TEST(BLI_string "bf_blenlib")
BLENDER_TEST(BLI_path_util "bf_blenlib;extern_wcwidth;${ZLIB_LIBRARIES}")
BLENDER_TEST(BLI_polyfill2d "bf_blenlib")
BLENDER_TEST(BLI_listbase "bf_blenlib")
BLENDER_TEST(BLI_hash_mm2a "bf_blenlib")