【发布时间】：2013-07-11 14:05:46
【问题描述】：
我正在从 Web 表单上传 cab 文件，并希望将其解压缩到内存中。我试过用CabInfo 文件解决这个问题，但没有成功。我知道how to unpack a cab file to my local disk，但不知道如何在内存中应用它。
任何帮助将不胜感激。
【问题讨论】：
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Adam_G - 对您有帮助吗？
【发布时间】：2013-07-11 14:05:46
【问题描述】：
【讨论】：
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谢谢瓦迪姆。不幸的是，我的公司不允许我使用 3rd-party 库。
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不过，我可以使用 p/invoke，这将允许我使用 c++ API FDICopy() (msdn.microsoft.com/en-us/library/bb432270(v=vs.85).aspx)。你知道我将如何使用这段代码来实现吗？
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看一下我建议使用的项目的源码。特别是在 Extract.hpp。有一个名为 ExtractFileW 的函数，如果 msw_TargetDir 为“MEMORY”，则 mb_ExtractToMemory 设置为 true。这反过来会影响 FdiWrite 的工作方式。当您创建 FDIContext 时，您提供自己的写入处理程序，该处理程序获取数据，如果 mb_ExtractToMemory 为真，它将将其写入内存。但是，您似乎无法使用单个 PINVOKE 执行所有这些操作。我会根据上述代码创建自己的 C++ dll 并对其进行 PINVOKE。
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魔法真的发生在 FCICreate 和 FNFCIWRITE 上。据我所知，您必须编写自己的 FNFCIWRITE（或重用项目中的部分），调用 FCICreate，然后才调用 FDICOPY。
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谢谢瓦迪姆。我暂时不得不跳过项目的这一部分，但很快就会回复你。
您最初的问题似乎表明您可以使用 Microsoft.Deployment.Compression DLL。如果为真，下面的代码应该能让你接近你想要的：
CabEngine engine = new CabEngine();
foreach (ArchiveFileInfo archiveFileInfo in engine.GetFileInfo(fileStream))
{
Stream stream = engine.Unpack(fileStream, archiveFileInfo.Name);
byte[] buffer = new byte[stream.Length];
//The (int) below is a dirty trick for demonstration purposes only;
//re-work for production code
stream.Read(buffer, 0, (int)stream.Length);
}
您后来的回答似乎表明您不允许使用第 3 方 DLL，在这种情况下您需要使用 FDI* API。此链接包含一些代码，您可以通过使用硬编码路径到（内存）流进行修改：Extract .cab file in C#
【讨论】：
有一个现成的项目可以下载：Cabinet File (*.CAB) Compression and Extraction
根据自 2008 年 9 月以来的版本历史"..you can extract directly to memory."
【讨论】：
这是一个应该在内存中工作的实用程序类（它支持 x86 或 x64 编译）。如果我们假设已使用标准上传协议将 .CAB 文件上传到 ASP.NET，那么您将使用它：
using (CabFile file = new CabFile(HttpContext.Current.Request.Files[0].InputStream))
{
file.EntryExtract += CabEntryExtract;
file.ExtractEntries();
}
static void CabEntryExtract(object sender, CabEntryExtractEventArgs e)
{
// e.Entry.Name contains the entry name
// e.Entry.Data contains a byte[] with the entry data
// e.Entry.LastWriteTime contains the entry last write time
// e.Entry.Size contains the entry uncompressed size
}
这里是实用程序和相关的类：
public sealed class CabFile : IDisposable
{
private IntPtr _hfdi;
private ERF _erf;
private GCHandle _erfHandle;
private byte[] _data;
private Dictionary<IntPtr, object> _handles = new Dictionary<IntPtr, object>();
private MemoryStream _currentEntryData;
private FNALLOC _alloc;
private FNCLOSE _close;
private FNFREE _free;
private FNOPEN _open;
private FNREAD _read;
private FNWRITE _write;
private FNSEEK _seek;
private FNFDINOTIFY _extract;
public event EventHandler<CabEntryExtractEventArgs> EntryExtract;
public CabFile(string filePath)
: this(GetStream(filePath))
{
}
private static Stream GetStream(string filePath)
{
if (filePath == null)
throw new ArgumentNullException("filePath");
return new FileStream(filePath, FileMode.Open, FileAccess.Read, FileShare.Read);
}
public CabFile(Stream stream)
{
if (stream == null)
throw new ArgumentNullException("stream");
using (MemoryStream data = new MemoryStream())
{
stream.CopyTo(data);
_data = data.ToArray();
}
_erf = new ERF();
_alloc = new FNALLOC(FnAlloc);
_free = new FNFREE(FnFree);
_close = new FNCLOSE(FnClose);
_open = new FNOPEN(FnOpen);
_read = new FNREAD(FnRead);
_write = new FNWRITE(FnWrite);
_seek = new FNSEEK(FnSeek);
_extract = new FNFDINOTIFY(FnNotifyExtract);
_erfHandle = GCHandle.Alloc(_erf, GCHandleType.Pinned);
_hfdi = FDICreate(
Marshal.GetFunctionPointerForDelegate(_alloc),
Marshal.GetFunctionPointerForDelegate(_free),
Marshal.GetFunctionPointerForDelegate(_open),
Marshal.GetFunctionPointerForDelegate(_read),
Marshal.GetFunctionPointerForDelegate(_write),
Marshal.GetFunctionPointerForDelegate(_close),
Marshal.GetFunctionPointerForDelegate(_seek)
, -1, _erfHandle.AddrOfPinnedObject());
}
public void ExtractEntries()
{
FDICopy(_hfdi, string.Empty, string.Empty, 0, Marshal.GetFunctionPointerForDelegate(_extract), IntPtr.Zero, IntPtr.Zero);
}
public void Dispose()
{
if (_hfdi != IntPtr.Zero)
{
FDIDestroy(_hfdi);
_hfdi = IntPtr.Zero;
}
_erfHandle.Free();
}
private void OnEntryExtract(CabEntry entry)
{
EventHandler<CabEntryExtractEventArgs> handler = EntryExtract;
if (handler != null)
{
handler(this, new CabEntryExtractEventArgs(entry));
}
}
private IntPtr FnAlloc(int cb)
{
return Marshal.AllocHGlobal(cb);
}
private void FnFree(IntPtr pv)
{
Marshal.FreeHGlobal(pv);
}
private IntPtr FnOpen(string pszFile, int oflag, int pmode)
{
// only used for reading archive
IntPtr h = new IntPtr(_handles.Count + 1);
_handles.Add(h, 0);
return h;
}
private int FnRead(IntPtr hf, byte[] pv, int cb)
{
// only used for reading archive
int pos = (int)_handles[hf];
int left = _data.Length - pos;
int read = Math.Min(left, cb);
if (read > 0)
{
Array.Copy(_data, pos, pv, 0, read);
_handles[hf] = pos + read;
}
return read;
}
private int FnWrite(IntPtr hf, byte[] pv, int cb)
{
// only used for writing entries
_currentEntryData.Write(pv, 0, cb);
return cb;
}
private int FnClose(IntPtr hf)
{
object o = _handles[hf];
CabEntry entry = o as CabEntry;
if (entry != null)
{
entry.Data = _currentEntryData.ToArray();
_currentEntryData.Dispose();
}
_handles.Remove(hf);
return 0;
}
private int FnSeek(IntPtr hf, int dist, SeekOrigin seektype)
{
// only used for seeking archive
int pos;
switch (seektype)
{
case SeekOrigin.Begin:
pos = dist;
break;
case SeekOrigin.Current:
pos = (int)_handles[hf] + dist;
break;
//case SeekOrigin.End:
default:
pos = _data.Length + dist;
break;
}
_handles[hf] = pos;
return pos;
}
private IntPtr FnNotifyExtract(FDINOTIFICATIONTYPE fdint, FDINOTIFICATION fdin)
{
CabEntry entry;
switch (fdint)
{
case FDINOTIFICATIONTYPE.COPY_FILE:
entry = new CabEntry(fdin);
entry._handle = new IntPtr(_handles.Count + 1);
_handles.Add(entry._handle, entry);
_currentEntryData = new MemoryStream();
return entry._handle;
case FDINOTIFICATIONTYPE.CLOSE_FILE_INFO:
entry = (CabEntry)_handles[fdin.hf];
FnClose(fdin.hf);
OnEntryExtract(entry);
return new IntPtr(1);
default:
return IntPtr.Zero;
}
}
private enum FDINOTIFICATIONTYPE
{
CABINET_INFO = 0,
PARTIAL_FILE = 1,
COPY_FILE = 2,
CLOSE_FILE_INFO = 3,
NEXT_CABINET = 4,
ENUMERATE = 5,
}
[StructLayout(LayoutKind.Sequential)]
private struct ERF
{
public int erfOper;
public int erfType;
public int fError;
}
[StructLayout(LayoutKind.Sequential, CharSet = CharSet.Ansi)]
internal class FDINOTIFICATION
{
public int cb;
public IntPtr psz1;
public IntPtr psz2;
public IntPtr psz3;
public IntPtr pv;
public IntPtr hf;
public ushort date;
public ushort time;
public ushort attribs;
public ushort setID;
public ushort iCabinet;
public ushort iFolder;
public int fdie;
}
[UnmanagedFunctionPointer(CallingConvention.Cdecl)]
private delegate IntPtr FNALLOC(int cb);
[UnmanagedFunctionPointer(CallingConvention.Cdecl)]
private delegate void FNFREE(IntPtr pv);
[UnmanagedFunctionPointer(CallingConvention.Cdecl, CharSet = CharSet.Ansi)]
private delegate IntPtr FNOPEN(string pszFile, int oflag, int pmode);
[UnmanagedFunctionPointer(CallingConvention.Cdecl)]
private delegate int FNREAD(IntPtr hf, [Out, MarshalAs(UnmanagedType.LPArray, SizeParamIndex = 2)] byte[] pv, int cb);
[UnmanagedFunctionPointer(CallingConvention.Cdecl)]
private delegate int FNWRITE(IntPtr hf, [MarshalAs(UnmanagedType.LPArray, SizeParamIndex = 2)] byte[] pv, int cb);
[UnmanagedFunctionPointer(CallingConvention.Cdecl)]
private delegate int FNCLOSE(IntPtr hf);
[UnmanagedFunctionPointer(CallingConvention.Cdecl)]
private delegate int FNSEEK(IntPtr hf, int dist, SeekOrigin seektype);
[UnmanagedFunctionPointer(CallingConvention.Cdecl)]
private delegate IntPtr FNFDINOTIFY(FDINOTIFICATIONTYPE fdint, FDINOTIFICATION pfdin);
[DllImport("cabinet.dll", CallingConvention = CallingConvention.Cdecl, CharSet = CharSet.Ansi)]
private static extern IntPtr FDICreate(IntPtr pfnalloc, IntPtr pfnfree, IntPtr pfnopen, IntPtr pfnread, IntPtr pfnwriter, IntPtr pfnclose, IntPtr pfnseek, int cpuType, IntPtr perf);
[DllImport("cabinet.dll", CallingConvention = CallingConvention.Cdecl)]
private static extern IntPtr FDIDestroy(IntPtr hdfi);
[DllImport("cabinet.dll", CallingConvention = CallingConvention.Cdecl, CharSet = CharSet.Ansi)]
private static extern IntPtr FDICopy(IntPtr hdfi, string pszCabinet, string pszCabPath, int flags, IntPtr fnNotify, IntPtr fnDecrypt, IntPtr userData);
}
public sealed class CabEntry
{
internal IntPtr _handle;
internal CabEntry(CabFile.FDINOTIFICATION fdin)
{
Name = Marshal.PtrToStringAnsi(fdin.psz1);
Size = fdin.cb;
LastWriteTime = new DateTime(1980 + GetMask(fdin.date, 9, 15), GetMask(fdin.date, 5, 8), GetMask(fdin.date, 0, 4),
GetMask(fdin.time, 11, 15), GetMask(fdin.time, 5, 10), 2 * GetMask(fdin.time, 0, 4));
}
private static int GetMask(int value, byte startByte, byte endByte)
{
int final = 0;
int v = 1;
for (byte b = startByte; b <= endByte; b++)
{
if ((value & (1 << b)) != 0)
{
final += v;
}
v = v * 2;
}
return final;
}
public string Name { get; private set; }
public int Size { get; private set; }
public DateTime LastWriteTime { get; private set; }
public byte[] Data { get; internal set; }
}
public sealed class CabEntryExtractEventArgs : EventArgs
{
public CabEntryExtractEventArgs(CabEntry entry)
{
if (entry == null)
throw new ArgumentNullException("entry");
Entry = entry;
}
public CabEntry Entry { get; private set; }
}
注意：此代码分配大字节 [] 块，因此可以对其进行优化以使用诸如 ChunkedMemoryStream 之类的东西（例如在此库中可用：CodeFluent Runtime Client）而不是字节 []，以避免影响 LOH (Large Object Heap)太多了。
【讨论】：