/// <summary>
/// Returns an IFilter for the given <paramref name="stream"/>
/// when there is no filter available
/// </summary>
/// <param name="stream">An <see cref="Stream"/></param>
/// <param name="extension">The file extension</param>
/// <param name="disableEmbeddedContent">When set to <c>true</c> embedded content is NOT read</param>
/// <param name="fileName">The name of the file</param>
/// <param name="readIntoMemory">When set to <c>true</c> the <paramref name="stream"/> is completely read
/// into memory first before the iFilters starts to read chunks, when set to <c>false</c> the iFilter reads
/// directly from the <paramref name="stream"/> and advances reading when the chunks are returned.
/// Default set to <c>false</c></param>
/// <returns><see cref="NativeMethods.IFilter"/> or null when no IFilter DLL is</returns>
public static NativeMethods.IFilter LoadAndInitIFilter(Stream stream,
string extension,
bool disableEmbeddedContent,
string fileName = "",
bool readIntoMemory = false)
{
// Find the dll and ClassID
GetFilterDllAndClass(extension, out var dllName, out var filterPersistClass);
var iFilter = LoadFilterFromDll(dllName, filterPersistClass);
if (iFilter == null)
{
return(null);
}
var iflags = NativeMethods.IFILTER_INIT.CANON_HYPHENS |
NativeMethods.IFILTER_INIT.CANON_PARAGRAPHS |
NativeMethods.IFILTER_INIT.CANON_SPACES |
NativeMethods.IFILTER_INIT.APPLY_INDEX_ATTRIBUTES |
NativeMethods.IFILTER_INIT.APPLY_CRAWL_ATTRIBUTES |
NativeMethods.IFILTER_INIT.APPLY_OTHER_ATTRIBUTES |
NativeMethods.IFILTER_INIT.HARD_LINE_BREAKS |
NativeMethods.IFILTER_INIT.FILTER_OWNED_VALUE_OK |
NativeMethods.IFILTER_INIT.EMIT_FORMATTING;
if (disableEmbeddedContent)
{
iflags = iflags | NativeMethods.IFILTER_INIT.DISABLE_EMBEDDED;
}
// ReSharper disable once SuspiciousTypeConversion.Global
var iPersistStream = iFilter as NativeMethods.IPersistStream;
// IPersistStream is asumed on 64 bits systems
if (iPersistStream != null)
{
// Create a COM stream
IStream comStream;
if (readIntoMemory)
{
// Copy the content to global memory
var buffer = new byte[stream.Length];
stream.Read(buffer, 0, buffer.Length);
var nativePtr = Marshal.AllocHGlobal(buffer.Length);
Marshal.Copy(buffer, 0, nativePtr, buffer.Length);
NativeMethods.CreateStreamOnHGlobal(nativePtr, true, out comStream);
}
else
{
comStream = new IStreamWrapper(stream);
}
try
{
iPersistStream.Load(comStream);
if (iFilter.Init(iflags, 0, IntPtr.Zero, out _) == NativeMethods.IFilterReturnCode.S_OK)
{
return(iFilter);
}
}
catch (Exception exception)
{
if (string.IsNullOrWhiteSpace(fileName))
{
throw new IFOldFilterFormat("An error occured while trying to load a stream with the IPersistStream interface", exception);
}
}
}
if (string.IsNullOrWhiteSpace(fileName))
{
throw new IFOldFilterFormat("The IFilter does not support the IPersistStream interface, supply a filename to use the IFilter");
}
// If we get here we probably are using an old IFilter so try to load it the old way
// ReSharper disable once SuspiciousTypeConversion.Global
if (iFilter is IPersistFile persistFile)
{
persistFile.Load(fileName, 0);
if (iFilter.Init(iflags, 0, IntPtr.Zero, out _) == NativeMethods.IFilterReturnCode.S_OK)
{
return(iFilter);
}
}
// If we failed to retreive an IPersistStream or IPersistFile interface or to initialize
// the filter, we release it and return null.
Marshal.ReleaseComObject(iFilter);
return(null);
}
/// <summary>
/// Returns an IFilter for the given <paramref name="stream"/>
/// when there is no filter available
/// </summary>
/// <param name="stream">An <see cref="Stream"/></param>
/// <param name="extension">The file extension</param>
/// <param name="disableEmbeddedContent">When set to <c>true</c> embedded content is NOT read</param>
/// <param name="fileName">The name of the file</param>
/// <param name="readIntoMemory">When set to <c>true</c> the <paramref name="stream"/> is completely read
/// into memory first before the iFilters starts to read chunks, when set to <c>false</c> the iFilter reads
/// directly from the <paramref name="stream"/> and advances reading when the chunks are returned.
/// Default set to <c>false</c></param>
/// <returns><see cref="NativeMethods.IFilter"/> or null when no IFilter DLL is</returns>
public static NativeMethods.IFilter LoadAndInitIFilter(Stream stream,
string extension,
bool disableEmbeddedContent,
string fileName = "",
bool readIntoMemory = false)
{
string dllName, filterPersistClass;
// Find the dll and ClassID
GetFilterDllAndClass(extension, out dllName, out filterPersistClass);
var iFilter = LoadFilterFromDll(dllName, filterPersistClass);
if (iFilter == null)
return null;
var iflags = NativeMethods.IFILTER_INIT.CANON_HYPHENS |
NativeMethods.IFILTER_INIT.CANON_PARAGRAPHS |
NativeMethods.IFILTER_INIT.CANON_SPACES |
NativeMethods.IFILTER_INIT.APPLY_INDEX_ATTRIBUTES |
NativeMethods.IFILTER_INIT.APPLY_CRAWL_ATTRIBUTES |
NativeMethods.IFILTER_INIT.APPLY_OTHER_ATTRIBUTES |
NativeMethods.IFILTER_INIT.HARD_LINE_BREAKS |
NativeMethods.IFILTER_INIT.FILTER_OWNED_VALUE_OK |
NativeMethods.IFILTER_INIT.EMIT_FORMATTING;
if (disableEmbeddedContent)
iflags = iflags | NativeMethods.IFILTER_INIT.DISABLE_EMBEDDED;
// ReSharper disable once SuspiciousTypeConversion.Global
var iPersistStream = iFilter as NativeMethods.IPersistStream;
// IPersistStream is asumed on 64 bits systems
if (iPersistStream != null)
{
// Create a COM stream
IStream comStream;
if (readIntoMemory)
{
// Copy the content to global memory
var buffer = new byte[stream.Length];
stream.Read(buffer, 0, buffer.Length);
var nativePtr = Marshal.AllocHGlobal(buffer.Length);
Marshal.Copy(buffer, 0, nativePtr, buffer.Length);
NativeMethods.CreateStreamOnHGlobal(nativePtr, true, out comStream);
}
else
comStream = new IStreamWrapper(stream);
iPersistStream.Load(comStream);
NativeMethods.IFILTER_FLAGS flags;
if (iFilter.Init(iflags, 0, IntPtr.Zero, out flags) == NativeMethods.IFilterReturnCode.S_OK)
return iFilter;
}
if (string.IsNullOrWhiteSpace(fileName))
throw new IFOldFilterFormat("The IFilter does not support the IPersistStream interface, supply a filename to use the IFilter");
// If we get here we probably are using an old IFilter so try to load it the old way
// ReSharper disable once SuspiciousTypeConversion.Global
var persistFile = iFilter as IPersistFile;
if (persistFile != null)
{
persistFile.Load(fileName, 0);
NativeMethods.IFILTER_FLAGS flags;
if (iFilter.Init(iflags, 0, IntPtr.Zero, out flags) == NativeMethods.IFilterReturnCode.S_OK)
return iFilter;
}
// If we failed to retreive an IPersistStream or IPersistFile interface or to initialize
// the filter, we release it and return null.
Marshal.ReleaseComObject(iFilter);
return null;
}
