ddidderr/zstd-rs
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rewrite fingerprint storage to no longer need 64-bit members

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so that it can be stored using standard alignment requirement (sizeof(void*)).

Distance function still requires 64-bit signed multiplication though,
so it won't change the issue regarding the bug in ubsan for clang 32-bit on github ci.
This commit is contained in:
Yann Collet
2024-10-23 11:50:57 -07:00
parent 57239c4d3b
commit b68ddce818
2 changed files with 13 additions and 13 deletions
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lib/compress/zstd_preSplit.c
+10 -10
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@@ -33,8 +33,8 @@ static unsigned hash2(const void *p)
typedef struct {
int events[HASHTABLESIZE];
S64 nbEvents;
unsigned events[HASHTABLESIZE];
size_t nbEvents;
} Fingerprint;
typedef struct {
Fingerprint pastEvents;
@@ -78,15 +78,15 @@ static void recordFingerprint(Fingerprint* fp, const void* src, size_t s, addEve
addEvents(fp, src, s);
}
static S64 abs64(S64 i) { return (i < 0) ? -i : i; }
static U64 abs64(S64 s64) { return (U64)((s64 < 0) ? -s64 : s64); }
static S64 fpDistance(const Fingerprint* fp1, const Fingerprint* fp2)
static U64 fpDistance(const Fingerprint* fp1, const Fingerprint* fp2)
{
S64 distance = 0;
U64 distance = 0;
size_t n;
for (n = 0; n < HASHTABLESIZE; n++) {
distance +=
abs64(fp1->events[n] * fp2->nbEvents - fp2->events[n] * fp1->nbEvents);
abs64((S64)fp1->events[n] * (S64)fp2->nbEvents - (S64)fp2->events[n] * (S64)fp1->nbEvents);
}
return distance;
}
@@ -100,9 +100,9 @@ static int compareFingerprints(const Fingerprint* ref,
{
assert(ref->nbEvents > 0);
assert(newfp->nbEvents > 0);
{ S64 p50 = ref->nbEvents * newfp->nbEvents;
S64 deviation = fpDistance(ref, newfp);
S64 threshold = p50 * (THRESHOLD_BASE + penalty) / THRESHOLD_PENALTY_RATE;
{ U64 p50 = (U64)ref->nbEvents * (U64)newfp->nbEvents;
U64 deviation = fpDistance(ref, newfp);
U64 threshold = p50 * (U64)(THRESHOLD_BASE + penalty) / THRESHOLD_PENALTY_RATE;
return deviation >= threshold;
}
}
@@ -150,7 +150,7 @@ static size_t ZSTD_splitBlock_byChunks(const void* src, size_t srcSize,
assert(blockSizeMax == (128 << 10));
assert(workspace != NULL);
assert((size_t)workspace % ZSTD_ALIGNOF(FPStats) == 0);
ZSTD_STATIC_ASSERT(ZSTD_SLIPBLOCK_WORKSPACESIZE == sizeof(FPStats));
ZSTD_STATIC_ASSERT(ZSTD_SLIPBLOCK_WORKSPACESIZE >= sizeof(FPStats));
assert(wkspSize >= sizeof(FPStats)); (void)wkspSize;
initStats(fpstats);