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fix incorrect round up calculation

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This was SVN commit r1182.
This commit is contained in:
janwas 2004-09-21 16:59:50 +00:00
parent eb2989176e
commit ff4af72da1
1 changed files with 15 additions and 9 deletions
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24
source/lib/sysdep/win/waio.cpp
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@ -404,16 +404,22 @@ static int aio_rw(struct aiocb* cb)
const bool is_file = (GetFileType(h) == FILE_TYPE_DISK);
if(is_file)
{
const size_t ofs_misalign = ofs % sector_size;
// round offset down to start of previous sector, and total
// transfer size up to an integral multiple of sector_size.
r->pad = ofs % sector_size;
actual_ofs = ofs - r->pad;
actual_size = round_up(size + r->pad, sector_size);
// now decide if any of the original parameters was unaligned,
// and whether it was ofs or buf in particular
// (needed for unaligned write handling below).
const bool ofs_misaligned = r->pad != 0;
const bool buf_misaligned = (uintptr_t)buf % sector_size != 0;
const size_t size_misalign = (size + ofs_misalign) % sector_size;
const bool misaligned = ofs_misaligned || buf_misaligned || actual_size != size;
// note: actual_size != size if ofs OR size is unaligned
r->pad = ofs_misalign;
actual_ofs = ofs - ofs_misalign;
actual_size = size + (size_misalign? sector_size : 0);
// need to realign if ofs, size, or buf % sector_size != 0
bool misaligned = ofs_misalign || buf_misaligned || size_misalign;
// misaligned => will need to go through align buffer
// (we fail some types of misalignment for convenience; see below).
if(misaligned)
{
// expand current align buffer if too small
@ -438,7 +444,7 @@ static int aio_rw(struct aiocb* cb)
{
// unaligned offset: not supported.
// (we'd have to read padding, then write our data. ugh.)
if(ofs_misalign)
if(ofs_misaligned)
{
ret = -EINVAL;
goto fail;