reactos/irc/TechBot/CHMLibrary/CHMDecoding/CHMUrlstr.cs

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C#
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using System;
using System.IO;
using System.Collections;
using System.Collections.Specialized;
namespace HtmlHelp.ChmDecoding
{
/// <summary>
/// The class <c>CHMUrlstr</c> implements a string collection storing the URL strings of the help file
/// </summary>
internal sealed class CHMUrlstr : IDisposable
{
/// <summary>
/// Constant specifying the size of the string blocks
/// </summary>
private const int BLOCK_SIZE = 0x1000;
/// <summary>
/// Internal flag specifying if the object is going to be disposed
/// </summary>
private bool disposed = false;
/// <summary>
/// Internal member storing the binary file data
/// </summary>
private byte[] _binaryFileData = null;
/// <summary>
/// Internal member storing the url dictionary
/// </summary>
private Hashtable _urlDictionary = new Hashtable();
/// <summary>
/// Internal member storing the framename dictionary
/// </summary>
private Hashtable _framenameDictionary = new Hashtable();
/// <summary>
/// Internal member storing the associated chmfile object
/// </summary>
private CHMFile _associatedFile = null;
/// <summary>
/// Constructor of the class
/// </summary>
/// <param name="binaryFileData">binary file data of the #URLSTR file</param>
/// <param name="associatedFile">associated chm file</param>
public CHMUrlstr(byte[] binaryFileData, CHMFile associatedFile)
{
_binaryFileData = binaryFileData;
_associatedFile = associatedFile;
DecodeData();
// clear internal binary data after extraction
_binaryFileData = null;
}
/// <summary>
/// Standard constructor
/// </summary>
internal CHMUrlstr()
{
}
#region Data dumping
/// <summary>
/// Dump the class data to a binary writer
/// </summary>
/// <param name="writer">writer to write the data</param>
internal void Dump(ref BinaryWriter writer)
{
writer.Write( _urlDictionary.Count );
if (_urlDictionary.Count != 0)
{
IDictionaryEnumerator iDictionaryEnumerator = _urlDictionary.GetEnumerator();
while (iDictionaryEnumerator.MoveNext())
{
DictionaryEntry dictionaryEntry = (DictionaryEntry)iDictionaryEnumerator.Current;
writer.Write( Int32.Parse(dictionaryEntry.Key.ToString()) );
writer.Write( dictionaryEntry.Value.ToString() );
}
}
writer.Write( _framenameDictionary.Count );
if (_framenameDictionary.Count != 0)
{
IDictionaryEnumerator iDictionaryEnumerator = _framenameDictionary.GetEnumerator();
while (iDictionaryEnumerator.MoveNext())
{
DictionaryEntry dictionaryEntry = (DictionaryEntry)iDictionaryEnumerator.Current;
writer.Write( Int32.Parse(dictionaryEntry.Key.ToString()) );
writer.Write( dictionaryEntry.Value.ToString() );
}
}
}
/// <summary>
/// Reads the object data from a dump store
/// </summary>
/// <param name="reader">reader to read the data</param>
internal void ReadDump(ref BinaryReader reader)
{
int i=0;
int nCnt = reader.ReadInt32();
for(i=0; i<nCnt;i++)
{
int nKey = reader.ReadInt32();
string sValue = reader.ReadString();
_urlDictionary[nKey.ToString()] = sValue;
}
nCnt = reader.ReadInt32();
for(i=0; i<nCnt;i++)
{
int nKey = reader.ReadInt32();
string sValue = reader.ReadString();
_framenameDictionary[nKey.ToString()] = sValue;
}
}
/// <summary>
/// Sets the associated CHMFile instance
/// </summary>
/// <param name="associatedFile">instance to set</param>
internal void SetCHMFile(CHMFile associatedFile)
{
_associatedFile = associatedFile;
}
#endregion
/// <summary>
/// Decodes the binary file data and fills the internal properties
/// </summary>
/// <returns>true if succeeded</returns>
private bool DecodeData()
{
bool bRet = true;
MemoryStream memStream = new MemoryStream(_binaryFileData);
BinaryReader binReader = new BinaryReader(memStream);
int nCurOffset = 0;
while( (memStream.Position < memStream.Length) && (bRet) )
{
nCurOffset = (int)memStream.Position;
byte [] dataBlock = binReader.ReadBytes(BLOCK_SIZE);
bRet &= DecodeBlock(dataBlock, ref nCurOffset);
}
return bRet;
}
/// <summary>
/// Decodes a block of url-string data
/// </summary>
/// <param name="dataBlock">block of data</param>
/// <param name="nOffset">current file offset</param>
/// <returns>true if succeeded</returns>
private bool DecodeBlock( byte[] dataBlock, ref int nOffset )
{
bool bRet = true;
int blockOffset = nOffset;
MemoryStream memStream = new MemoryStream(dataBlock);
BinaryReader binReader = new BinaryReader(memStream);
if(nOffset==0)
binReader.ReadByte(); // first block starts with an unknown byte
while( (memStream.Position < (memStream.Length-8)) && (bRet) )
{
int entryOffset = blockOffset + (int)memStream.Position;
int urlOffset = binReader.ReadInt32();
int frameOffset = binReader.ReadInt32();
// There is one way to tell where the end of the URL/FrameName
// pairs occurs: Repeat the following: read 2 DWORDs and if both
// are less than the current offset then this is the start of the Local
// strings else skip two NT strings.
// if(( (urlOffset < (entryOffset+8)) && (frameOffset < (entryOffset+8)) ))
// {
// //TODO: add correct string reading if an offset has been found
// /*
// int curOffset = (int)memStream.Position;
//
// memStream.Seek( (long)(blockOffset-urlOffset), SeekOrigin.Begin);
// string sTemp = CHMReader.ExtractString(ref binReader, 0, true);
//
// memStream.Seek( (long)(blockOffset-frameOffset), SeekOrigin.Begin);
// sTemp = CHMReader.ExtractString(ref binReader, 0, true);
//
// memStream.Seek((long)curOffset, SeekOrigin.Begin);
// */
//
//
// int curOffs = (int)memStream.Position;
// BinaryReaderHelp.ExtractString(ref binReader, 0, true, _associatedFile.TextEncoding);
// nOffset += (int)memStream.Position - curOffs;
//
// curOffs = (int)memStream.Position;
// BinaryReaderHelp.ExtractString(ref binReader, 0, true, _associatedFile.TextEncoding);
// nOffset += (int)memStream.Position - curOffs;
// }
// else
{
bool bFoundTerminator = false;
string sTemp = BinaryReaderHelp.ExtractString(ref binReader, ref bFoundTerminator, 0, true, _associatedFile.TextEncoding);
if(sTemp == "")
{
//nOffset = nOffset + 1 + (int)memStream.Length - (int)memStream.Position;
memStream.Seek(memStream.Length-1, SeekOrigin.Begin);
}
else
{
_urlDictionary[entryOffset.ToString()] = sTemp.ToString();
_framenameDictionary[ entryOffset.ToString() ] = sTemp.ToString() ;
}
}
}
return bRet;
}
/// <summary>
/// Gets the url at a given offset
/// </summary>
/// <param name="offset">offset of url</param>
/// <returns>the url at the given offset</returns>
public string GetURLatOffset(int offset)
{
if(offset == -1)
return String.Empty;
string sTemp = (string)_urlDictionary[ offset.ToString() ];
if(sTemp == null)
return String.Empty;
return sTemp;
}
/// <summary>
/// Gets the framename at a given offset
/// </summary>
/// <param name="offset">offset of the framename</param>
/// <returns>the frame name at the given offset</returns>
public string GetFrameNameatOffset(int offset)
{
if(offset == -1)
return String.Empty;
string sTemp = (string)_framenameDictionary[ offset.ToString() ];
if(sTemp == null)
return String.Empty;
return sTemp;
}
/// <summary>
/// Implement IDisposable.
/// </summary>
public void Dispose()
{
Dispose(true);
// This object will be cleaned up by the Dispose method.
// Therefore, you should call GC.SupressFinalize to
// take this object off the finalization queue
// and prevent finalization code for this object
// from executing a second time.
GC.SuppressFinalize(this);
}
/// <summary>
/// Dispose(bool disposing) executes in two distinct scenarios.
/// If disposing equals true, the method has been called directly
/// or indirectly by a user's code. Managed and unmanaged resources
/// can be disposed.
/// If disposing equals false, the method has been called by the
/// runtime from inside the finalizer and you should not reference
/// other objects. Only unmanaged resources can be disposed.
/// </summary>
/// <param name="disposing">disposing flag</param>
private void Dispose(bool disposing)
{
// Check to see if Dispose has already been called.
if(!this.disposed)
{
// If disposing equals true, dispose all managed
// and unmanaged resources.
if(disposing)
{
// Dispose managed resources.
_binaryFileData = null;
_urlDictionary = null;
_framenameDictionary = null;
}
}
disposed = true;
}
}
}