Import TechBot

svn path=/trunk/; revision=13064

irc/TechBot/CHMLibrary/CHMDecoding/CHMUrltable.cs

@@ -0,0 +1,245 @@
+using System;
+using System.IO;
+using System.Collections;
+
+namespace HtmlHelp.ChmDecoding
+{
+	/// <summary>
+	/// The class <c>CHMUrltable</c> implements methods to decode the #URLTBL internal file.
+	/// </summary>
+	internal sealed class CHMUrltable : IDisposable
+	{
+		/// <summary>
+		/// Constant specifying the size of the data blocks
+		/// </summary>
+		private const int BLOCK_SIZE = 0x1000;
+		/// <summary>
+		/// Constant specifying the number of records per block
+		/// </summary>
+		private const int RECORDS_PER_BLOCK = 341;
+		/// <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 table
+		/// </summary>
+		private ArrayList _urlTable = new ArrayList();
+		/// <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 #URLTBL file</param>
+		/// <param name="associatedFile">associated chm file</param>
+		public CHMUrltable(byte[] binaryFileData, CHMFile associatedFile)
+		{
+			_binaryFileData = binaryFileData;
+			_associatedFile = associatedFile;
+			DecodeData();
+
+			// clear internal binary data after extraction
+			_binaryFileData = null;
+		}
+
+		/// <summary>
+		/// Standard constructor
+		/// </summary>
+		internal CHMUrltable()
+		{
+		}
+
+		#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( _urlTable.Count );
+			foreach(UrlTableEntry curItem in _urlTable)
+			{
+				curItem.Dump(ref writer);
+			}
+		}
+
+		/// <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++)
+			{
+				UrlTableEntry newItem = new UrlTableEntry();
+				newItem.SetCHMFile(_associatedFile);
+				newItem.ReadDump(ref reader);
+				_urlTable.Add(newItem);
+			}
+		}
+
+		/// <summary>
+		/// Sets the associated CHMFile instance
+		/// </summary>
+		/// <param name="associatedFile">instance to set</param>
+		internal void SetCHMFile(CHMFile associatedFile)
+		{
+			_associatedFile = associatedFile;
+
+			foreach(UrlTableEntry curEntry in _urlTable)
+			{
+				curEntry.SetCHMFile(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);
+
+			for(int i=0; i < RECORDS_PER_BLOCK; i++)
+			{
+				int recordOffset = blockOffset + (int)memStream.Position;
+
+				uint nuniqueID = (uint) binReader.ReadInt32(); // unknown dword
+				int ntopicsIdx = binReader.ReadInt32();
+				int urlstrOffset = binReader.ReadInt32();
+
+				UrlTableEntry newEntry = new UrlTableEntry(nuniqueID, recordOffset, ntopicsIdx, urlstrOffset, _associatedFile);
+				_urlTable.Add(newEntry);
+
+				if( memStream.Position >= memStream.Length)
+					break;
+			}
+
+			if(dataBlock.Length == BLOCK_SIZE)
+				binReader.ReadInt32();
+
+			return bRet;
+		}
+
+		/// <summary>
+		/// Gets the arraylist containing all urltable entries.
+		/// </summary>
+		public ArrayList UrlTable
+		{
+			get
+			{
+				return _urlTable;
+			}
+		}
+
+		/// <summary>
+		/// Gets the urltable entry of a given offset
+		/// </summary>
+		public UrlTableEntry this[int offset]
+		{
+			get
+			{
+				foreach(UrlTableEntry curEntry in _urlTable)
+					if(curEntry.EntryOffset == offset)
+						return curEntry;
+
+				return null;
+			}
+		}
+
+		/// <summary>
+		/// Gets the urltable entry of a given uniqueID
+		/// </summary>
+		public UrlTableEntry GetByUniqueID(uint uniqueID)
+		{
+			foreach(UrlTableEntry curEntry in UrlTable)
+			{
+				if(curEntry.UniqueID == uniqueID)
+					return curEntry;
+			}
+
+			return null;
+		}
+
+		/// <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;
+					_urlTable = null;
+				}
+			}
+			disposed = true;         
+		}
+	}
+}