Code:
/ DotNET / DotNET / 8.0 / untmp / WIN_WINDOWS / lh_tools_devdiv_wpf / Windows / wcp / Base / MS / Internal / IO / Packaging / CompoundFile / CFStream.cs / 1 / CFStream.cs
//------------------------------------------------------------------------------ // //// Copyright (C) Microsoft Corporation. All rights reserved. // // // Description: // Stream interface for manipulating data within a container stream. // // History: // 05/13/2002: [....]: Initial implementation. // 07/31/2002: [....]: Make obvious that we are using security suppressed interfaces. // 05/20/2003: [....]: Ported to WCP tree. // //----------------------------------------------------------------------------- using System; using System.IO; using System.Runtime.InteropServices; using System.IO.Packaging; using System.Windows; namespace MS.Internal.IO.Packaging.CompoundFile { ////// Class for manipulating data within container streams /// internal class CFStream : Stream { //----------------------------------------------------- // // Public Properties // //----------------------------------------------------- ////// See .NET Framework SDK under System.IO.Stream /// public override bool CanRead { get { return (!StreamDisposed && (FileAccess.Read == (access & FileAccess.Read) || FileAccess.ReadWrite == (access & FileAccess.ReadWrite))); } } ////// See .NET Framework SDK under System.IO.Stream /// public override bool CanSeek { get { // OLE32 DocFiles on local disk always seekable return (!StreamDisposed); // unless it's disposed } } ////// See .NET Framework SDK under System.IO.Stream /// public override bool CanWrite { get { return (!StreamDisposed && (FileAccess.Write == (access & FileAccess.Write) || FileAccess.ReadWrite == (access & FileAccess.ReadWrite))); } } ////// See .NET Framework SDK under System.IO.Stream /// public override long Length { get { CheckDisposedStatus(); System.Runtime.InteropServices.ComTypes.STATSTG streamStat; // STATFLAG_NONAME required on IStream::Stat _safeIStream.Stat( out streamStat, SafeNativeCompoundFileConstants.STATFLAG_NONAME ); return streamStat.cbSize; } } ////// See .NET Framework SDK under System.IO.Stream /// public override long Position { get { CheckDisposedStatus(); long seekPos = 0; _safeIStream.Seek( 0, // Offset of zero SafeNativeCompoundFileConstants.STREAM_SEEK_CUR, out seekPos ); return seekPos; } set { CheckDisposedStatus(); if (!CanSeek) { throw new NotSupportedException(SR.Get(SRID.SetPositionNotSupported)); } long seekPos = 0; _safeIStream.Seek( value , // given offset SafeNativeCompoundFileConstants.STREAM_SEEK_SET, out seekPos ); if( value != seekPos ) { throw new IOException( SR.Get(SRID.SeekFailed)); } } } //------------------------------------------------------ // // Public Methods // //----------------------------------------------------- ////// See .NET Framework SDK under System.IO.Stream /// public override void Flush() { CheckDisposedStatus(); _safeIStream.Commit(0); } ////// See .NET Framework SDK under System.IO.Stream /// /// Offset byte count /// Offset origin ///public override long Seek( long offset, SeekOrigin origin ) { CheckDisposedStatus(); if (!CanSeek) { throw new NotSupportedException(SR.Get(SRID.SeekNotSupported)); } // long seekPos = 0; int translatedSeekOrigin = 0; switch(origin) { case SeekOrigin.Begin: translatedSeekOrigin = SafeNativeCompoundFileConstants.STREAM_SEEK_SET; if( 0 > offset ) { throw new ArgumentOutOfRangeException("offset", SR.Get(SRID.SeekNegative)); } break; case SeekOrigin.Current: translatedSeekOrigin = SafeNativeCompoundFileConstants.STREAM_SEEK_CUR; // Need to find the current seek pointer to see if we'll end // up with a negative position. break; case SeekOrigin.End: translatedSeekOrigin = SafeNativeCompoundFileConstants.STREAM_SEEK_END; // Need to find the current seek pointer to see if we'll end // up with a negative position. break; default: throw new System.ComponentModel.InvalidEnumArgumentException("origin", (int) origin, typeof(SeekOrigin)); } _safeIStream.Seek( offset, translatedSeekOrigin, out seekPos ); return seekPos; } /// /// See .NET Framework SDK under System.IO.Stream /// /// New length public override void SetLength( long newLength ) { CheckDisposedStatus(); if (!CanWrite) { throw new NotSupportedException(SR.Get(SRID.SetLengthNotSupported)); } if( 0 > newLength ) { throw new ArgumentOutOfRangeException("newLength", SR.Get(SRID.StreamLengthNegative)); } _safeIStream.SetSize( newLength ); // updating the stream pointer if the stream has been truncated. if (newLength < this.Position) this.Position = newLength; } ////// See .NET Framework SDK under System.IO.Stream /// /// Read data buffer /// Buffer start position /// Number of bytes to read ///Number of bytes actually read public override int Read( byte[] buffer, int offset, int count ) { CheckDisposedStatus(); PackagingUtilities.VerifyStreamReadArgs(this, buffer, offset, count); int read = 0; if ( 0 == offset ) // Zero offset is typical case { _safeIStream.Read( buffer, count, out read ); } else // Non-zero offset { // Read into local array and then copy it into the given buffer at // the specified offset. byte[] localBuffer = new byte[count]; _safeIStream.Read( localBuffer, count, out read ); if (read > 0) Array.Copy(localBuffer, 0, buffer, offset, read); } return read; } ////// See .NET Framework SDK under System.IO.Stream /// /// Data buffer /// Buffer write start position /// Number of bytes to write public override void Write( byte[] buffer, int offset, int count ) { CheckDisposedStatus(); PackagingUtilities.VerifyStreamWriteArgs(this, buffer, offset, count); int written = 0; // CLR guys have deemed this uninteresting? if ( 0 == offset ) // Zero offset is typical case { _safeIStream.Write( buffer, count, out written ); } else // Non-zero offset { // Copy from indicated offset to zero-based temp buffer byte[] localBuffer = new byte[count]; Array.Copy(buffer, offset, localBuffer, 0, count); _safeIStream.Write( localBuffer, count, out written ); } if( count != written ) throw new IOException( SR.Get(SRID.WriteFailure)); } //------------------------------------------------------ // // Internal Methods // //------------------------------------------------------ // Check whether this Stream object is still valid. If not, thrown an // ObjectDisposedException. internal void CheckDisposedStatus() { if( StreamDisposed ) throw new ObjectDisposedException(null, SR.Get(SRID.StreamObjectDisposed)); } // Check whether this Stream object is still valid. internal bool StreamDisposed { get { return (backReference.StreamInfoDisposed || ( null == _safeIStream )); } } // Constructors internal CFStream( IStream underlyingStream, FileAccess openAccess, StreamInfo creator) { _safeIStream = underlyingStream; access = openAccess; backReference = creator; } //----------------------------------------------------- // // Protected Methods // //------------------------------------------------------ ////// Dispose(bool) /// /// protected override void Dispose(bool disposing) { try { if (disposing) { // As per CLR docs for Stream.Close, calls to close on dead stream produces no exceptions. if (null != _safeIStream) { // No need to call IStream.Commit, commiting at storage root level // is sufficient. // Can't do Marshal.ReleaseComObject() here because there's only // one COM ref for each RCW and there may be other users. _safeIStream = null; } } } finally { base.Dispose(disposing); } } //----------------------------------------------------- // // Private Members // //----------------------------------------------------- IStream _safeIStream; FileAccess access; ////// If only this stream object is held open, and the rest of the container /// has not been explicitly closed, we need this to keep the rest of the /// tree open because the CLR GC doesn't realize that our IStream has /// a dependency on the rest of the container object tree. /// StreamInfo backReference; } } // File provided for Reference Use Only by Microsoft Corporation (c) 2007. // Copyright (c) Microsoft Corporation. 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