这里有一些修改可以添加到DiscUtils 以支持FAT LFNs：
首先，对Fat\Directory.cs文件进行这些更改，像这样（你需要添加_lfns变量，GetLfnChunk函数，并修改现有的LoadEntries函数以添加标有@987654327的行@下面）：
internal Dictionary<string, string> _lfns = new Dictionary<string, string>(StringComparer.OrdinalIgnoreCase);
private static string GetLfnChunk(byte[] buffer)
{
// see http://home.teleport.com/~brainy/lfn.htm
// NOTE: we assume ordinals are ok here.
char[] chars = new char[13];
chars[0] = (char)(256 * buffer[2] + buffer[1]);
chars[1] = (char)(256 * buffer[4] + buffer[3]);
chars[2] = (char)(256 * buffer[6] + buffer[5]);
chars[3] = (char)(256 * buffer[8] + buffer[7]);
chars[4] = (char)(256 * buffer[10] + buffer[9]);
chars[5] = (char)(256 * buffer[15] + buffer[14]);
chars[6] = (char)(256 * buffer[17] + buffer[16]);
chars[7] = (char)(256 * buffer[19] + buffer[18]);
chars[8] = (char)(256 * buffer[21] + buffer[20]);
chars[9] = (char)(256 * buffer[23] + buffer[22]);
chars[10] = (char)(256 * buffer[25] + buffer[24]);
chars[11] = (char)(256 * buffer[29] + buffer[28]);
chars[12] = (char)(256 * buffer[31] + buffer[30]);
string chunk = new string(chars);
int zero = chunk.IndexOf('\0');
return zero >= 0 ? chunk.Substring(0, zero) : chunk;
}
private void LoadEntries()
{
_entries = new Dictionary<long, DirectoryEntry>();
_freeEntries = new List<long>();
_selfEntryLocation = -1;
_parentEntryLocation = -1;
string lfn = null; //+++
while (_dirStream.Position < _dirStream.Length)
{
long streamPos = _dirStream.Position;
DirectoryEntry entry = new DirectoryEntry(_fileSystem.FatOptions, _dirStream);
if (entry.Attributes == (FatAttributes.ReadOnly | FatAttributes.Hidden | FatAttributes.System | FatAttributes.VolumeId))
{
// Long File Name entry
_dirStream.Position = streamPos; //+++
lfn = GetLfnChunk(Utilities.ReadFully(_dirStream, 32)) + lfn; //+++
}
else if (entry.Name.IsDeleted())
{
// E5 = Free Entry
_freeEntries.Add(streamPos);
lfn = null; //+++
}
else if (entry.Name == FileName.SelfEntryName)
{
_selfEntry = entry;
_selfEntryLocation = streamPos;
lfn = null; //+++
}
else if (entry.Name == FileName.ParentEntryName)
{
_parentEntry = entry;
_parentEntryLocation = streamPos;
lfn = null; //+++
}
else if (entry.Name == FileName.Null)
{
// Free Entry, no more entries available
_endOfEntries = streamPos;
lfn = null; //+++
break;
}
else
{
if (lfn != null) //+++
{ //+++
_lfns.Add(entry.Name.GetDisplayName(_fileSystem.FatOptions.FileNameEncoding), lfn); //+++
} //+++
_entries.Add(streamPos, entry);
lfn = null; //+++
}
}
}
其次，将这两个公共函数添加到Fat\FatFileSystem.cs 文件中。它们将成为查询 LFN 的新 API：
/// <summary>
/// Gets the long name of a given file.
/// </summary>
/// <param name="shortFullPath">The short full path to the file. Input path segments must be short names.</param>
/// <returns>The corresponding long file name.</returns>
public string GetLongFileName(string shortFullPath)
{
if (shortFullPath == null)
throw new ArgumentNullException("shortFullPath");
string dirPath = Path.GetDirectoryName(shortFullPath);
string fileName = Path.GetFileName(shortFullPath);
Directory dir = GetDirectory(dirPath);
if (dir == null)
return fileName;
string lfn;
if (dir._lfns.TryGetValue(Path.GetFileName(shortFullPath), out lfn))
return lfn;
return fileName;
}
/// <summary>
/// Gets the long path to a given file.
/// </summary>
/// <param name="shortFullPath">The short full path to the file. Input path segments must be short names.</param>
/// <returns>The corresponding long file path to the file or null if not found.</returns>
public string GetLongFilePath(string shortFullPath)
{
if (shortFullPath == null)
throw new ArgumentNullException("shortFullPath");
string path = null;
string current = null;
foreach (string segment in shortFullPath.Split(Path.DirectorySeparatorChar))
{
if (current == null)
{
current = segment;
path = GetLongFileName(current);
}
else
{
current = Path.Combine(current, segment);
path = Path.Combine(path, GetLongFileName(current));
}
}
return path;
}
就是这样。现在，您可以像这样递归地转储整个 FAT 磁盘，例如：
static void Main(string[] args)
{
using (FileStream fs = File.Open("fat.ima", FileMode.Open))
{
using (FatFileSystem floppy = new FatFileSystem(fs))
{
Dump(floppy.Root);
}
}
}
static void Dump(DiscDirectoryInfo di)
{
foreach (DiscDirectoryInfo subdi in di.GetDirectories())
{
Dump(subdi);
}
foreach (DiscFileInfo fi in di.GetFiles())
{
Console.WriteLine(fi.FullName);
// get LFN name
Console.WriteLine(" " + ((FatFileSystem)di.FileSystem).GetLongFileName(fi.FullName));
// get LFN-ed full path
Console.WriteLine(" " + ((FatFileSystem)di.FileSystem).GetLongFilePath(fi.FullName));
}
}
使用风险自负！ :)