C#实现的内存分页机制的一个实例

C#实现的内存分页机制的一个实例

//多页索引表管理类(全局主索引表管理类)
    public class MuliPageIndexFeatureClass : IDisposable
    {
        protected List<IndexPageClass> MuliPageIndexTable = new List<IndexPageClass>();  //多页索引表对象
        //
        protected int CurrentMemoryPageIndex = -1;   //当前内存索引页(已载入内存的索引页的对象)
        public int PerPageDwCount = 30000;          //每页地物个数  default=3,0000

        /// <summary>
        /// = Application.StartupPath + "\\tempfiles\\tmp_vct";
        /// </summary>
        protected string tmpDir = Application.StartupPath + "\\tempfiles\\tmp_vct";

        public MuliPageIndexFeatureClass()
        {
            this.MemoryPageList.Clear();
            //txt存放目录
            string dir = this.tmpDir;
            if (System.IO.Directory.Exists(dir) == true)
            {
                try
                {
                    System.IO.Directory.Delete(dir, true);
                }
                catch { }
            }
            if(System.IO.Directory.Exists(dir) == false)
            {
                System.IO.Directory.CreateDirectory(dir);
            }
        }

        //创建多页索引表(建立多页索引表) 派生类需重写
        private IndexPageClass tmpIP = null;
        public virtual bool CreateMuliPageIndexTable(FeatureOIDMap pfeat)
        {
            //txt存放目录
            string dir = this.tmpDir;
            if (System.IO.Directory.Exists(dir) == false)
            {
                System.IO.Directory.CreateDirectory(dir);
            }
            //创建多页索引表....
            if (this.tmpIP == null)
            {   //产生一个新的索引页面
                this.tmpIP = new IndexPageClass();
                tmpIP.RelationFileName = "vctline" + this.MuliPageIndexTable.Count.ToString() + ".txt";
                tmpIP.CreatedIndex = false;
                tmpIP.OpenTxt();
                this.MuliPageIndexTable.Add(tmpIP);
            }
            else
            {
                if (tmpIP.dt.Count >=this.PerPageDwCount)
                {   //保存原有的索引页面
                    tmpIP.SaveToTxt();
                    tmpIP.CloseTxt();
                    tmpIP.CreatedIndex = true;
                    tmpIP.dt.Clear();
                    //产生一个新的索引页面
                    tmpIP = new IndexPageClass();
                    tmpIP.RelationFileName = "vctline" + this.MuliPageIndexTable.Count.ToString() + ".txt";
                    tmpIP.CreatedIndex = false;
                    tmpIP.OpenTxt();
                    this.MuliPageIndexTable.Add(tmpIP);
                }
            }
            if(tmpIP!=null)
            {
                tmpIP.dt.Add(pfeat.ObjectID,pfeat);
                if (tmpIP.dt.Count % 100==0)
                {
                    Application.DoEvents();
                }
            }
            return true;
        }
        public virtual bool SaveEndPageIndexTable()
        {
            bool rbc = false;
            if (tmpIP != null)
            {
                tmpIP.SaveToTxt();
                tmpIP.CloseTxt();
                tmpIP.CreatedIndex = true;
                tmpIP.dt.Clear();
                tmpIP.Dispose();
                tmpIP = null;
                rbc = true;
            }
            return rbc;
        }

        //选择记录集 OK
        private List<int> MemoryPageList = new List<int>();
        private int MemoryPagesOnLine = 7;   //在线的内存索引文件数
        public FeatureOIDMap GetLine(int bsm)
        {
            FeatureOIDMap feat = null;
            bool IsSearch = true;  //是否要进行分页搜索操作标志 默认为是

            if (this.CurrentMemoryPageIndex != -1)
            {   //当前内存分页中是否有dwID地物唯一编号
                if (this.MuliPageIndexTable[this.CurrentMemoryPageIndex].DwidList.Contains(bsm) == true)
                {
                    IsSearch = false;
                }
            }

            if (IsSearch == true)
            {   //进行分页搜索操作 并置为当前内存分页
                for (int i = 0; i < this.MuliPageIndexTable.Count; i++)
                {
                    if (this.MuliPageIndexTable[i].DwidList.Contains(bsm) == true)
                    {
                        if (this.CurrentMemoryPageIndex != i)
                        {
                            //需搜索页面不在当前内存页面中 (需置换页面)
                            if (this.CurrentMemoryPageIndex != -1)
                            {
                                //修正在线内存索引文件个数
                                if (this.MemoryPageList.Contains(i) == false)
                                {
                                    this.MemoryPageList.Add(i);
                                }
                                if (this.MemoryPageList.Contains(this.CurrentMemoryPageIndex) == false)
                                {
                                    this.MemoryPageList.Add(this.CurrentMemoryPageIndex);
                                }
                                if (this.MemoryPageList.Count > this.MemoryPagesOnLine)
                                {
                                    this.MemoryPageList.RemoveAt(0);
                                }
                                //清除离线内存索引文件中坐标大数据

                                for (int k = 0; k < this.MuliPageIndexTable.Count; k++)
                                {
                                    if (this.MemoryPageList.Contains(k) == false)
                                    {
                                        this.MuliPageIndexTable[k].Dispose();
                                    }
                                }
                            }
                            if (this.MuliPageIndexTable[i].dt.Count <= 0)
                            {
                                this.MuliPageIndexTable[i].ReadFromTxt();  //从txt文件中读取记录
                            }
                            this.CurrentMemoryPageIndex = i;
                            break;
                        }
                    } //end if
                } //end for
            }

            //当前分面页页进行搜索...
            if (this.CurrentMemoryPageIndex != -1)
            {
                feat = this.MuliPageIndexTable[this.CurrentMemoryPageIndex].GetLine(bsm);
            }
            return feat;
        }

        //获取一页索引表
        public IndexPageClass GetIndexPageClass(int index)
        {
            if (MuliPageIndexTable != null && this.MuliPageIndexTable.Count > index)
            {
                return this.MuliPageIndexTable[index];
            }
            return null;
        }

        public void Clear()
        {
            this.Dispose();
        }
        #region IDisposable 成员

        public void Dispose()
        {
            if (this.MuliPageIndexTable.Count > 0)
            {
                for (int i = 0; i < this.MuliPageIndexTable.Count; i++)
                {
                    this.MuliPageIndexTable[i].Dispose();
                }
            }
            this.MuliPageIndexTable.Clear();
            this.CurrentMemoryPageIndex = -1;
        }

        public void DeleteTempFile()
        {
            //分页对应的txt文件...
            string dir = this.tmpDir;
            if (System.IO.Directory.Exists(dir) == true)
            {
                try
                {
                    System.IO.Directory.Delete(dir, true);
                }
                catch
                {
                }
            }
        }

        #endregion
    }

//一页内索引表管理类
    public class IndexPageClass : IDisposable
    {
        public bool CreatedIndex = false;
        public List<int> DwidList = new List<int>();  //地物唯一编号的集合
        public string RelationFileDir = Application.StartupPath + "\\tempfiles\\tmp_vct";
        //相关的txt文件 dltb_xzdw_Relation_1.txt
        public string RelationFileName = "";
        //排序后的记录关系记录DataRow集合  //从_1.txt从读取内容
        protected FeatureOIDMapCollection m_dt = new FeatureOIDMapCollection();
        protected System.IO.StreamWriter sw = null;
        private int m_index = 0;

        //get dt
        public FeatureOIDMapCollection dt
        {
            get
            {
                return m_dt;
            }
        }

        /// <summary>
        /// //打开文本分页文件写入流
        /// </summary>
        public bool OpenTxt()
        {
            string relfilename = this.RelationFileDir + "\\" + this.RelationFileName;
            if (System.IO.File.Exists(relfilename) == true)
            {
                System.IO.File.Delete(relfilename);
            }
            this.sw = new StreamWriter(relfilename, true, Encoding.Default);
            return true;
        }

        /// <summary>
        /// 向写入流写入一行记录
        /// </summary>
        private bool AppentLine(string pLine)
        {
            if (this.sw != null)
            {
                this.sw.WriteLine(pLine);
                this.m_index += 1;

                if (this.m_index % 10000 == 0)
                {
                    this.sw.Flush();
                    Application.DoEvents();
                }
            }
            return true;
        }
        /// <summary>
        /// 向写入流写入一行记录
        /// </summary>
        private bool AppentLine(FeatureOIDMap pFeatureOIDMap)
        {
            StringBuilder pline = new StringBuilder();
            CoPointClass cpoint = null;
            //常住内存索引
            this.DwidList.Add(pFeatureOIDMap.ObjectID);
            //
            pline.Append(pFeatureOIDMap.ObjectID.ToString());
            for (int i = 0; i < pFeatureOIDMap.PointArray.Count; i++)
            {
                cpoint=pFeatureOIDMap.PointArray[i] as CoPointClass;
                pline.Append("," + cpoint.X.ToString() + "," + cpoint.Y.ToString());
            }
            return AppentLine(pline.ToString());
        }

        //保存到txt文件中
        public bool SaveToTxt()
        {
            bool rbc = false;
            if (this.dt != null)
            {
                foreach(FeatureOIDMap featmap in this.dt.Values)
                {
                    this.AppentLine(featmap);
                }
                rbc = true;
            }
            return rbc;
        }

        /// <summary>
        /// 关闭写入流
        /// </summary>
        public bool CloseTxt()
        {
            if (sw != null)
            {
                sw.Flush();
                sw.Close();
                sw.Dispose();
                sw = null;
            }
            return true;
        }

        //从txt中读取记录到m_dt表中  OK
        public virtual bool ReadFromTxt()
        {
            this.Dispose();
            int t_index = 0;
            int bsm=0;
            double x = 0;
            double y = 0;
            System.IO.StreamReader sr = new System.IO.StreamReader(this.RelationFileDir + "\\" + this.RelationFileName, Encoding.Default);
            string line = sr.ReadLine();
            while (line != null && line != "")
            {
                t_index += 1;
                if (t_index % 100 == 0)
                {
                    Application.DoEvents();
                }
                //向m_dt中加入一行记录
                string[] lineArray = line.Split(new char[] { ',' });
                bsm=int.Parse(lineArray[0]);
                FeatureOIDMap feat_new = new FeatureOIDMap(bsm);
                for (int i = 1; i < lineArray.Length; i+=2)
                {
                    CoPointClass xpPoint = new CoPointClass();
                    x = 0;
                    y = 0;
                    double.TryParse(lineArray[i], out x);
                    double.TryParse(lineArray[i+1], out y);
                    xpPoint.X = x;
                    xpPoint.Y = y;
                    //
                    feat_new.PointArray.Add(xpPoint);
                }
                this.m_dt.Add(feat_new.ObjectID,feat_new);
                //
                line = sr.ReadLine();
            }
            sr.Close();
            sr.Dispose();
            sr = null;
            return true;
        }

        //从内存页面中选择记录集 OK
        public FeatureOIDMap GetLine(int bsm)
        {
            FeatureOIDMap feat = null;
            if (m_dt != null && m_dt.Count <= 0)
            {
                this.ReadFromTxt();
            }
            if (m_dt != null && m_dt.Count > 0)
            {
                feat = this.m_dt.GetIndexByOID(bsm);
            }
            return feat;
        }

        #region IDisposable 成员

        public void Dispose()
        {
            if (m_dt != null)
            {
                m_dt.Clear();
            }
        }
        #endregion
    }