using System;
using System.Collections.Generic;
using System.Text;

namespace tgreer
{
	public class indexer
	{
		private Dictionary<string, Int32> _documents;
		private Dictionary<string, Int32> _pages;
		
		public indexer()
		{
			// class constructor
			_documents = new Dictionary<string, Int32>(250);
			_pages = new Dictionary<string, Int32>(1000);
		}

		public void addDocIndex(string _seq, Int32 _offset)
		{
			_documents.Add(_seq, _offset);
			
		}

		public void addPageIndex(string _seq, Int32 _offset)
		{
			_pages.Add(_seq, _offset);

		}
	}
}

using System;
using System.IO;
using System.Collections.Generic;
using System.Xml;
using System.Xml.Serialization;

namespace tgreer
{
	[XmlRoot("indexer")]
	public class indexer
	{
		[XmlElement("documents")]
		private Dictionary<string, Int32> _documents;

		[XmlElement("pages")]
		private Dictionary<string, Int32> _pages;
		
		public indexer()
		{
			// class constructor
			_documents = new Dictionary<string, Int32>(250);
			_pages = new Dictionary<string, Int32>(1000);
		}
		public void addDocIndex(string _seq, Int32 _offset)
		{
			_documents.Add(_seq, _offset);
			
		}

		public void addPageIndex(string _seq, Int32 _offset)
		{
			_pages.Add(_seq, _offset);

		}

		public void serializeMe()
		{
			// Serialization
			XmlSerializer s = new XmlSerializer(this.GetType());
			TextWriter w = new StreamWriter(@"c:\index.xml");
			s.Serialize(w, this);
			w.Close();
		}
	}
}

using System;
using System.IO;
using System.Collections;
using System.Collections.Generic;
using System.Runtime.Serialization;
using System.Runtime.Serialization.Formatters.Binary;

namespace TGREER
{
	[Serializable]
	public class Document
	{
		private string _seq;
		private Int32 _offset;

		public Document(string _seq, Int32 _offset)
		{
			this._seq = _seq;
			this._offset = _offset;
		}

		public override string ToString()
		{
			return _seq;
		}

		public string GenericSequenceNo
		{
			get { return _seq; }
			set { _seq = value; }
		}

		public Int32 ByteOffset
		{
			get { return _offset; }
			set { _offset = value; }
		}
	}

	[Serializable]
	public class Page
	{
		private string _seq;
		private Int32 _offset;

		public Page(string _seq, Int32 _offset)
		{
			this._seq = _seq;
			this._offset = _offset;
		}

		public override string ToString()
		{
			return _seq;
		}

		public string GenericSequenceNo
		{
			get { return _seq; }
			set { _seq = value; }
		}

		public Int32 ByteOffset
		{
			get { return _offset; }
			set { _offset = value; }
		}
	}

	public class Indexer
	{
		private string _psFilename;
		private string _key;

		private List<Document> _documents;
		private List<Page> _pages;

		private Document _document;
		private Page _page;

		// constructor, creates empty lists
		public Indexer(string _filename)
		{
			_psFilename = _filename;
			_documents = new List<Document>();
			_pages = new List<Page>();
		}

		// constructor, re-creates lists from serialized files
		public Indexer(string _filename, string _docName, string _pgName)
		{
			_psFilename = _filename;

			FileStream _s = new FileStream(_docName, FileMode.Open);
			BinaryFormatter formatter = new BinaryFormatter();
			_documents = (List<Document>)formatter.Deserialize(_s);
			_s.Close();

			_s = new FileStream(_pgName, FileMode.Open);
			formatter = new BinaryFormatter();
			_pages = (List<Page>)formatter.Deserialize(_s);
			_s.Close();
		}

		// public method to add entry to documents list
		public void addDocIndex(string _seq, Int32 _offset)
		{
			_document = new Document(_seq, _offset);
			_documents.Add(_document);
		}

		// public method to add entry to pages list
		public void addPageIndex(string _seq, Int32 _offset)
		{
			_page = new Page(_seq, _offset);
			_pages.Add(_page);
		}

		// public method to serialize list contents to named files
		public void serialize(string _docName, string _pgName)
		{
			FileStream _s = new FileStream(_docName, FileMode.Create);
			BinaryFormatter formatter = new BinaryFormatter();
			formatter.Serialize(_s, _documents);
			_s.Close();

			_s = new FileStream(_pgName, FileMode.Create);
			formatter = new BinaryFormatter();
			formatter.Serialize(_s, _pages);
			_s.Close();
		}

		// public method to return a string containing a document
		public string getDocument(string _key)
		{
			this._key = _key;
			_document = _documents.Find(isKey);

			Int32 _i = _documents.IndexOf(_document);
			Int32 _byteStart = _document.ByteOffset;
			Int32 _byteEnd = _documents[_i + 1].ByteOffset - 1;
			Int32 _bytesToRead = _byteEnd - _byteStart;

			FileStream _s = new FileStream(_psFilename, FileMode.Open);
			StreamReader _sr = new StreamReader(_s);
			_s.Seek(_byteStart, SeekOrigin.Begin);

			char[] _buffer = new char[_bytesToRead];
			Int32 _bytesRead = _sr.ReadBlock(_buffer, 0, _bytesToRead);
			_s.Close();

			return new string(_buffer);
		}

		// public method to return a string containing a page
		public string getPage(string _key)
		{
			this._key = _key;
			_page = _pages.Find(isKey);

			Int32 _i = _pages.IndexOf(_page);
			Int32 _byteStart = _page.ByteOffset;
			Int32 _byteEnd = _pages[_i + 1].ByteOffset - 1;
			Int32 _bytesToRead = _byteEnd - _byteStart;

			FileStream _s = new FileStream(_psFilename, FileMode.Open);
			StreamReader _sr = new StreamReader(_s);
			_s.Seek(_byteStart, SeekOrigin.Begin);

			char[] _buffer = new char[_bytesToRead];
			Int32 _bytesRead = _sr.ReadBlock(_buffer, 0, _bytesToRead);
			_s.Close();

			return new string(_buffer);

		}

		// Predicate used for searching the List. Presumably, this is optimized so is faster than a forall loop?
		private bool isKey(Document _d)
		{
			if (_d.GenericSequenceNo == this._key)
			{
				return true;
			}
			else
			{
				return false;
			}
		}

		private bool isKey(Page _p)
		{
			if (_p.GenericSequenceNo == this._key)
			{
				return true;
			}
			else
			{
				return false;
			}
		}
	}
}