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bloom: add test helper to return murmur3 hash

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In bloom.h, murmur3_seeded_v2() is exported for the use of test murmur3
hash. To clarify that murmur3_seeded_v2() is exported solely for testing
purposes, a new helper function test_murmur3_seeded() was added instead
of exporting murmur3_seeded_v2() directly.

Signed-off-by: Lidong Yan <502024330056@smail.nju.edu.cn>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
This commit is contained in:
Lidong Yan
2025-07-12 17:35:13 +08:00
committed by Junio C Hamano
parent 16bd9f20a4
commit 4ca7017902
3 changed files with 17 additions and 12 deletions
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13
bloom.c
View File

@@ -107,7 +107,7 @@ int load_bloom_filter_from_graph(struct commit_graph *g,
* Not considered to be cryptographically secure.
* Implemented as described in https://en.wikipedia.org/wiki/MurmurHash#Algorithm
*/
uint32_t murmur3_seeded_v2(uint32_t seed, const char *data, size_t len)
static uint32_t murmur3_seeded_v2(uint32_t seed, const char *data, size_t len)
{
const uint32_t c1 = 0xcc9e2d51;
const uint32_t c2 = 0x1b873593;
@@ -540,3 +540,14 @@ int bloom_filter_contains(const struct bloom_filter *filter,
return 1;
}
uint32_t test_bloom_murmur3_seeded(uint32_t seed, const char *data, size_t len,
int version)
{
assert(version == 1 || version == 2);
if (version == 2)
return murmur3_seeded_v2(seed, data, len);
else
return murmur3_seeded_v1(seed, data, len);
}

12
bloom.h
View File

@@ -78,15 +78,6 @@ int load_bloom_filter_from_graph(struct commit_graph *g,
struct bloom_filter *filter,
uint32_t graph_pos);
/*
* Calculate the murmur3 32-bit hash value for the given data
* using the given seed.
* Produces a uniformly distributed hash value.
* Not considered to be cryptographically secure.
* Implemented as described in https://en.wikipedia.org/wiki/MurmurHash#Algorithm
*/
uint32_t murmur3_seeded_v2(uint32_t seed, const char *data, size_t len);
void fill_bloom_key(const char *data,
size_t len,
struct bloom_key *key,
@@ -137,4 +128,7 @@ int bloom_filter_contains(const struct bloom_filter *filter,
const struct bloom_key *key,
const struct bloom_filter_settings *settings);
uint32_t test_bloom_murmur3_seeded(uint32_t seed, const char *data, size_t len,
int version);
#endif

4
t/helper/test-bloom.c
View File

@@ -61,13 +61,13 @@ int cmd__bloom(int argc, const char **argv)
uint32_t hashed;
if (argc < 3)
usage(bloom_usage);
hashed = murmur3_seeded_v2(0, argv[2], strlen(argv[2]));
hashed = test_bloom_murmur3_seeded(0, argv[2], strlen(argv[2]), 2);
printf("Murmur3 Hash with seed=0:0x%08x\n", hashed);
}
if (!strcmp(argv[1], "get_murmur3_seven_highbit")) {
uint32_t hashed;
hashed = murmur3_seeded_v2(0, "\x99\xaa\xbb\xcc\xdd\xee\xff", 7);
hashed = test_bloom_murmur3_seeded(0, "\x99\xaa\xbb\xcc\xdd\xee\xff", 7, 2);
printf("Murmur3 Hash with seed=0:0x%08x\n", hashed);
}