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)
????{
?????// 提取該記錄前后相同的數據
?????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大于要查找的Key，則向前查找
????{
?????if (recEnd <= recStart) break;
?????recEnd = curRowNo - 1;
????}
????else??????????????????? // 當前記錄Key小于要查找的Key，則向后查找
????{
?????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;
???fs.Seek(position, 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里
??/// </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 "";
?????}
????}
???}

??}
??????
?}
}
?