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align buffer at 64-byte boundary so that memcpy can take advantage of… #1141

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align buffer at 64-byte boundary so that memcpy can take advantage of… #1141

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4 changes: 2 additions & 2 deletions dokan/dokan.c
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Original file line number Diff line number Diff line change
Expand Up @@ -1366,8 +1366,8 @@ VOID DOKANAPI DokanMapKernelToUserCreateFileFlags(
}

VOID DOKANAPI DokanInit() {
// ensure 64-bit alignment
assert(FIELD_OFFSET(EVENT_INFORMATION, Buffer) % 8 == 0);
// ensure 64-byte alignment, memcpy runs much faster on 64-byte aligned buffer on moden CPU
static_assert(FIELD_OFFSET(EVENT_INFORMATION, Buffer) % 64 == 0, "alignment error");

// this is not as safe as a critical section so to some degree we rely on
// the user to do the right thing
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1 change: 1 addition & 0 deletions sys/public.h
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Expand Up @@ -388,6 +388,7 @@ typedef struct _EVENT_INFORMATION {
ULONG64 Context;
ULONG BufferLength;
ULONG PullEventTimeoutMs;
UCHAR Padding[24]; // ensure buffer is 64-byte aligned
UCHAR Buffer[DOKAN_EVENT_INFO_MIN_BUFFER_SIZE];
} EVENT_INFORMATION, *PEVENT_INFORMATION;

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