ForwardReader.cs :  » Persistence-Frameworks » FileHelpers-Library » FileHelpers » C# / CSharp Open Source

using System;
using System.Globalization;
using System.IO;
using System.Text;

namespace FileHelpers{
  internal sealed class ForwardReader
  {
    TextReader mReader;

    private string[] mFowardStrings;
    private int mForwardIndex = 0;
    
    internal char[] mEOF = StringHelper.NewLine.ToCharArray();
    internal int mCapacityHint = 64;

    private int mRemaingLines = 0;

    public int RemainingLines
    {
      get { return mRemaingLines; }
    }
    
    private int mLineNumber = 0;

    public int LineNumber
    {
      get {return mLineNumber - 1;}
    }
    
//    
//    int mPos = 0;
//    int MaxRecordSize = 1024 * 8;
//    char[] mBuffer;
//    
    internal ForwardReader(TextReader reader)
      : this(reader, 0, 0)
    {
    }

    internal ForwardReader(TextReader reader, int forwardLines): 
      this(reader, forwardLines, 0)
    {
    }

    internal ForwardReader(TextReader reader, int forwardLines, int startLine)
    {
      mReader = reader;
      
      mFowardLines = forwardLines;
      mLineNumber = startLine;

      mFowardStrings = new string[mFowardLines + 1];
      mRemaingLines = mFowardLines + 1;

      for (int i = 0; i < mFowardLines + 1; i++)
      {
        mFowardStrings[i] = mReader.ReadLine();
        mLineNumber++;
        if (mFowardStrings[i] == null)
        {
          mRemaingLines = i;
          break;
        }
      }

    }

    
//    public string ReadToDelimiter(string del)
//    {
//      //StringBuilder builder = new StringBuilder(mCapacityHint);
//
//      int right = mPos;
//      while (true)
//      {
//        mReader.
//        
//        //mReader.Read()
//        
//      }
//      
//      
//      
//      if (builder.Length > 0)
//      {
//        return builder.ToString();
//      }
//      return null;
//    }

    private bool mDiscardForward = false;

    public bool DiscardForward
    {
      get { return mDiscardForward; }
      set { mDiscardForward = value; }
    }

    private int mFowardLines = 0;

    public int FowardLines
    {
      get { return mFowardLines; }
    }

    public string ReadNextLine()
    {
      if (mRemaingLines <= 0)
        return null;
      else
      {
        string res = mFowardStrings[mForwardIndex];

        if (mRemaingLines == (mFowardLines + 1))
        {
          mFowardStrings[mForwardIndex] = mReader.ReadLine();
          mLineNumber++;

          if (mFowardStrings[mForwardIndex] == null)
          {
            mRemaingLines--;
          }

        }
        else
        {
          mRemaingLines--;
          if (mDiscardForward)
            return null;

        }

        mForwardIndex = (mForwardIndex + 1)%(mFowardLines + 1);

        return res;
      }

    }

    public string RemainingText
    {
      get
      {
        StringBuilder sb = new StringBuilder(100);

        for (int i = 0; i < mRemaingLines + 1; i++)
        {
          sb.Append(mFowardStrings[(mForwardIndex + i)%(mFowardLines + 1)] + StringHelper.NewLine);
        }

        return sb.ToString();
      }
    }


    public void Close()
    {
      mReader.Close();
    }

  }

}