https://git.reactos.org/?p=reactos.git;a=commitdiff;h=c08d37d182408f69533644257ee8cc10e6a16f6b
commit c08d37d182408f69533644257ee8cc10e6a16f6b Author: Trevor Thompson <[email protected]> AuthorDate: Thu Jul 7 08:17:07 2016 +0000 [NTFS] Simplify and optimize InternalSetResidentAttributeLength(), as suggested by Pierre. svn path=/branches/GSoC_2016/NTFS/; revision=71837 --- drivers/filesystems/ntfs/mft.c | 34 ++++++++++++++-------------------- 1 file changed, 14 insertions(+), 20 deletions(-) diff --git a/drivers/filesystems/ntfs/mft.c b/drivers/filesystems/ntfs/mft.c index a5111c18ee..aa203bbe9d 100644 --- a/drivers/filesystems/ntfs/mft.c +++ b/drivers/filesystems/ntfs/mft.c @@ -178,43 +178,37 @@ InternalSetResidentAttributeLength(PNTFS_ATTR_CONTEXT AttrContext, ULONG AttrOffset, ULONG DataSize) { - ULONG EndMarker = AttributeEnd; - ULONG FinalMarker = FILE_RECORD_END; + PNTFS_ATTR_RECORD Destination = (PNTFS_ATTR_RECORD)((ULONG_PTR)FileRecord + AttrOffset); ULONG NextAttributeOffset; - ULONG Offset; - USHORT Padding; DPRINT("InternalSetResidentAttributeLength( %p, %p, %lu, %lu )\n", AttrContext, FileRecord, AttrOffset, DataSize); // update ValueLength Field - AttrContext->Record.Resident.ValueLength = DataSize; - Offset = AttrOffset + FIELD_OFFSET(NTFS_ATTR_RECORD, Resident.ValueLength); - RtlCopyMemory((PCHAR)FileRecord + Offset, &DataSize, sizeof(ULONG)); + AttrContext->Record.Resident.ValueLength = + Destination->Resident.ValueLength = DataSize; // calculate the record length and end marker offset - AttrContext->Record.Length = DataSize + AttrContext->Record.Resident.ValueOffset; + AttrContext->Record.Length = + Destination->Length = DataSize + AttrContext->Record.Resident.ValueOffset; NextAttributeOffset = AttrOffset + AttrContext->Record.Length; // Ensure NextAttributeOffset is aligned to an 8-byte boundary if (NextAttributeOffset % 8 != 0) { - Padding = 8 - (NextAttributeOffset % 8); + USHORT Padding = 8 - (NextAttributeOffset % 8); NextAttributeOffset += Padding; AttrContext->Record.Length += Padding; + Destination->Length += Padding; } + + // advance Destination to the final "attribute" and write the end type + (ULONG_PTR)Destination += Destination->Length; + Destination->Type = AttributeEnd; - // update the record length - Offset = AttrOffset + FIELD_OFFSET(NTFS_ATTR_RECORD, Length); - RtlCopyMemory((PCHAR)FileRecord + Offset, &AttrContext->Record.Length, sizeof(ULONG)); + // write the final marker (which shares the same offset and type as the Length field) + Destination->Length = FILE_RECORD_END; - // write the end marker - RtlCopyMemory((PCHAR)FileRecord + NextAttributeOffset, &EndMarker, sizeof(ULONG)); - - // write the final marker - Offset = NextAttributeOffset + sizeof(ULONG); - RtlCopyMemory((PCHAR)FileRecord + Offset, &FinalMarker, sizeof(ULONG)); - - FileRecord->BytesInUse = Offset + sizeof(ULONG); + FileRecord->BytesInUse = NextAttributeOffset + (sizeof(ULONG) * 2); } NTSTATUS
