I am trying to read directories from an EXFAT USB drive. And for this task, I have found here a good documentation: https://docs.microsoft.com/en-us/win...-specification
But seem that is unclear somehow, at least to me.
I have successfully read - Main and Backup Boot Sector Structure Table (https://docs.microsoft.com/en-us/win...ctor-structure), value by value.
And then, I have read - Cluster Heap Structure Table (https://docs.microsoft.com/en-us/win...heap-structure)
and for every cluster from cluster heap, I retrieved a CByteArray of 32768 bytes. Fine by now. Now, there is another part: Directory Structure Table (https://docs.microsoft.com/en-us/win...tory-structure)
Here I am stuck. I guess I can read the directory (or files) from this cluster, one by one. Theoretically, I should read every cluster from 32 to 32 bytes, according Directory Structure Table, which gave me 1024 (32768 / 32). But in this cluster, I don't know how to consider those bytes in order to have a directory (or file). More over, I don't know how to compute N (for DirectoryEntry[N1]).
The documentation says: N, the number of DirectoryEntry fields, is the size, in bytes, of the cluster chain which contains the given directory, divided by the size of a DirectoryEntry field, 32 bytes.
From documentation: A cluster chain is a series of clusters which provides space for recording the contents of files, directories, and other file system structures.
Now, how is: "cluster chain which contains the given directory" ? Can you help me a little bit ? I am stuck here for a while, and I don't know how to move on ...
But seem that is unclear somehow, at least to me.
I have successfully read - Main and Backup Boot Sector Structure Table (https://docs.microsoft.com/en-us/win...ctor-structure), value by value.
And then, I have read - Cluster Heap Structure Table (https://docs.microsoft.com/en-us/win...heap-structure)
Code:
const int nSize = dwSectorSize * 1 << nSectorsPerClusterShift;
const int nCount = nClusterCount + 1;
LONGLONG llPos = nClusterHeapOffset;
LONGLONG nLimit = nClusterHeapOffset + ((nClusterCount - 1) * nSize);
for (int i = 0; i < nCount; ++i)
{
file.Seek(llPos, CFile::begin);
arrByte.RemoveAll();
arrByte.SetSize(nSize);
UINT nRet = file.Read(arrByte.GetData(), arrByte.GetSize());
llPos += nSize;
if (llPos > nLimit)
break;
}Here I am stuck. I guess I can read the directory (or files) from this cluster, one by one. Theoretically, I should read every cluster from 32 to 32 bytes, according Directory Structure Table, which gave me 1024 (32768 / 32). But in this cluster, I don't know how to consider those bytes in order to have a directory (or file). More over, I don't know how to compute N (for DirectoryEntry[N1]).
The documentation says: N, the number of DirectoryEntry fields, is the size, in bytes, of the cluster chain which contains the given directory, divided by the size of a DirectoryEntry field, 32 bytes.
From documentation: A cluster chain is a series of clusters which provides space for recording the contents of files, directories, and other file system structures.
Now, how is: "cluster chain which contains the given directory" ? Can you help me a little bit ? I am stuck here for a while, and I don't know how to move on ...