文本二叉樹折半查詢及其截取值

using System;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Text;
using System.Windows.Forms;
using System.Collections;
using System.IO;
namespace CS_ScanSample1
{
 /// <summary>
 /// Logic 的摘要說明。
 /// </summary>
 public class Logic
 {
  /// <summary>
  /// 從排序文本中查找指定關鍵字的行
  /// </summary>
  /// <param name="path">路徑</param>
  /// <param name="keyString">關鍵字</param>
  /// <param name="rowLength">一行的長度</param>
  /// <param name="keyStart">開始位置</param>
  /// <param name="keyLength">取的長度</param>
  public static DataTable Find(string path, string keyString, int rowLength, int keyStart, int keyLength)
  {
   DataTable ddt=new DataTable();
   ddt.Columns.Add("Titlex");
   ddt.Columns.Add("BookNum");
   long s = DateTime.Now.Ticks;

   ArrayList list = new ArrayList();
   FileStream fs = File.Open(path, FileMode.Open, FileAccess.Read);
   long fileLength = fs.Length;
   int recCount = (int)(fileLength / rowLength);
   int recStart = 0;
   int recEnd = recCount;
   string rowKeyString;
   int curRowNo = 0;
   int result;
   curRowNo = (recStart + recEnd) / 2;
   int seekCount = 0;
      byte[] rowBytes;

   do
   {
    seekCount++;
    rowBytes = ReadRow(fs, curRowNo, rowLength);
    rowKeyString = Encoding.Default.GetString(rowBytes, keyStart, keyLength).Trim();
    result = rowKeyString.CompareTo(keyString);
    if (result == 0)
  &nb

$False$

sp; {
     // 提取該記錄前後相同的數據
     int recMore = curRowNo;
     do
     {
     // list.Add(Encoding.Default.GetString(rowBytes));
      ddt = InStrOutTable(Encoding.Default.GetString(rowBytes,0,rowBytes.Length),ddt);
      recMore++;

      rowBytes = ReadRow(fs, recMore, rowLength);
      rowKeyString = Encoding.Default.GetString(rowBytes, keyStart, keyLength).Trim();
      result = rowKeyString.CompareTo(keyString);

     } while (result == 0 && recMore <= recCount);
     recMore = curRowNo - 1;
     do
     {
      rowBytes = ReadRow(fs, recMore, rowLength);
      rowKeyString = Encoding.Default.GetString(rowBytes, keyStart, keyLength).Trim();
      result = rowKeyString.CompareTo(keyString);
      recMore--;
      if (result == 0)
      {
      // list.Add(Encoding.Default.GetString(rowBytes));
       ddt = InStrOutTable( Encoding.Default.GetString(rowBytes,0,rowBytes.Length),ddt);
      }

     } while (result == 0 && recMore >= 0);
     break;
    }
    else if (result > 0)    // 當前記錄Key大於要查找的Key，則向前查找
    {
     if (recEnd <= recStart) break;
     recEnd = curRowNo - 1;
    }
    else                    // 當前記錄Key小於要查找的Key，

則向後查找
    {
     if (recStart >= recEnd) break;
     recStart = curRowNo + 1;
    }
    curRowNo = (recStart + recEnd) / 2;
   } while (true);

   fs.Close();
   long e = DateTime.Now.Ticks;
   //Console.WriteLine("Time={0},Times={1}", TimeSpan.FromTicks(e - s), seekCount);

   return ddt;
   //  return list;
          
  }
      

  private static byte[] ReadRow(FileStream fs, int recno, int rowLength)
  {
   
   byte[] rowBytes = new byte[rowLength - 2];
   if(recno <0) return rowBytes;
   int position = recno * rowLength;
   fsposition, SeekOrigin.Begin);
   fs.Read(rowBytes, 0, rowLength - 2);
   return rowBytes;
  }
  public static DataTable InStrOutTable( string arowStr,DataTable Dt)
  {
   string ztm = MySubstring(arowStr, 20, 60).Trim().Replace("''", "’");
   int fbs = Convert.ToInt32((MySubstring(arowStr, 120, 10).Trim().Replace("''", "’")=="") ? "0" :MySubstring(arowStr, 120, 10).Trim().Replace("''", "’"));
   return InputDataTable( ztm, fbs,Dt);

  }

  //////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////

 

  /// <summary>
  /// 把一行加入DataTable裡
  /// </summary>
  /// <param name="ZykDt1">DataTable</param>
  /// <param name="idxstr">IdxStr</param>
  /// <param name="Titlexstr">Title</param>
  /// <;param name="booknumstr">nCopIEs</param>
  /// <returns></returns>
  private static DataTable InputDataTable( string Titlexstr, int booknumstr,DataTable ZykDt1)
  {

  
   string Titlex = Titlexstr;
   int BookNum = booknumstr;
   DataRow row = ZykDt1.NewRow();
   row["Titlex"] = Titlex;
   row["BookNum"] = BookNum;
   ZykDt1.Rows.Add(row);
   return ZykDt1;

  }
  /// <summary>
  /// 取字符
  /// </summary>
  /// <param name="string1">字符串</param>
  /// <param name="start">開始位置</param>
  /// <param name="length">長度</param>
  /// <returns></returns>
  private static string MySubstring(string string1, int start, int length)
  {

   if (string1 == "" || string1 == null)
   {
    return "";
   }
   else
   {
    byte[] s = Encoding.Default.GetBytes(string1);
    if (s.Length >= start + length)
    {
     return Encoding.Default.GetString(s, start, length);
    }
    else
    {
     if (s.Length > start)
     {
      return Encoding.Default.GetString(s, start, s.Length - start);
     }
     else
     {
      return "";
     }
    }
   }

  }
      
 }
}