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windows support for disk physical offset

This commit is contained in:
Arvid Norberg 2009-09-06 07:44:45 +00:00
parent afaf6df46b
commit d0cb5049f7
2 changed files with 36 additions and 3 deletions
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3
include/libtorrent/file.hpp
View File

@ -178,6 +178,9 @@ namespace libtorrent
int m_open_mode;
#if defined TORRENT_WINDOWS || defined TORRENT_LINUX
mutable int m_sector_size;
#endif
#if defined TORRENT_WINDOWS
mutable int m_cluster_size;
#endif
};

36
src/file.cpp
View File

@ -283,9 +283,16 @@ namespace libtorrent
if (GetDiskFreeSpace(m_path.substr(0, m_path.find_first_of(backslash)+1).c_str()
, &sectors_per_cluster, &bytes_per_sector
, &free_clusters, &total_clusters))
{
m_sector_size = bytes_per_sector;
m_cluster_size = sectors_per_cluster * bytes_per_sector;
}
else
m_sector_size = 4096;
{
// make a conservative guess
m_sector_size = 512;
m_cluster_size = 4096;
}
}
return m_sector_size;
#else
@ -797,6 +804,7 @@ namespace libtorrent
// the returned extent is not guaranteed to start
// at the requested offset, adjust for that in
// case they differ
TORRENT_ASSERT(offset >= fm.fiemap.fm_extents[0].fe_logical);
return fm.fiemap.fm_extents[0].fe_physical + (offset - fm.fiemap.fm_extents[0].fe_logical);
#elif defined F_LOG2PHYS
@ -806,8 +814,30 @@ namespace libtorrent
log2phys l;
size_type ret = lseek(m_fd, offset, SEEK_SET);
if (ret < 0) return 0;
if (fcntl(m_fd, F_LOG2PHYS, &l) != -1)
return l.l2p_devoffset;
if (fcntl(m_fd, F_LOG2PHYS, &l) == -1) return 0;
return l.l2p_devoffset;
#elif defined TORRENT_WINDOWS
// for documentation of this feature
// http://msdn.microsoft.com/en-us/library/aa364572(VS.85).aspx
STARTING_VCN_INPUT_BUFFER in;
RETRIEVAL_POINTERS_BUFFER out;
DWORD out_bytes;
// query cluster size
pos_alignment();
in.StartingVcn.QuadPart = offset / m_cluster_size;
int cluster_offset = in.StartingVcn.QuadPart % m_cluster_size;
if (DeviceIoControl(m_file_handle, FSCTL_GET_RETRIEVAL_POINTERS, &in
, sizeof(in), &out, sizeof(out), &out_bytes, 0) == 0)
return 0;
if (out_bytes < sizeof(out)) return 0;
if (out.ExtentCount == 0) return 0;
if (out.Extents[0].Lcn.QuadPart == (LONGLONG)-1) return 0;
TORRENT_ASSERT(in.StartingVcn.QuadPart >= out.StartingVcn.QuadPart);
return (out.Extents[0].Lcn.QuadPart
+ (in.StartingVcn.QuadPart - out.StartingVcn.QuadPart))
* m_cluster_size + cluster_offset;
#endif
return 0;
}