本文主要是介绍封装：内存镜像文件（MemoryMappedFile）封装，一维二维三维定点访问，希望对大家解决编程问题提供一定的参考价值，需要的开发者们随着小编来一起学习吧！
MemoryMappedFile简介：
1、问题：公司底层限制使用32位应用程序，针对大数据数据模型会产生内存溢出；
2、解决方案：C#中可以使用MemoryMappedFile类将内存映射到硬盘中，将大网格数据保存在硬盘中节省内存；
3、实测结果：读取写入速度可以接受，持久化效果良好；
4、针对使用结构进行了如下封装，可用于泛型索引访问
/// <summary> 泛型 T 内存映射文件 </summary>public partial class MmfEntity<T> where T : struct{#region - 成员变量 -private long _size;/// <summary> 文件大小 </summary>public long Size{get { return _size; }}/// <summary> 实体大小 </summary>public int MLeight{get { return Marshal.SizeOf(typeof(T)); }}private int _count;/// <summary> T 类型的数量 </summary>public int Count{get { return _count; }set{// 设置容器大小this._size = MLeight * value;_count = value;}}private string _file;/// <summary> 文件全路径 </summary>public string FileInf{get { return _file; }set { _file = value; }}private string _name;/// <summary> 镜像名称 </summary>public string Name{get{if (string.IsNullOrEmpty(_name)){_name = Path.GetFileNameWithoutExtension(_file);}return _name;}}private MemoryMappedFile _mmf;/// <summary> 内存镜像 </summary>protected MemoryMappedFile Mmf{get{BuildFile();return _mmf;}}/// <summary> 创建文件 </summary>void BuildFile(){if (File.Exists(this.FileInf)){this.Dispose();File.Delete(this.FileInf);}// 如果存在删除_mmf = MemoryMappedFile.CreateFromFile(this.FileInf, FileMode.OpenOrCreate, _name, _size, MemoryMappedFileAccess.ReadWriteExecute);}private MemoryMappedViewAccessor _mapView;/// <summary> 随机访问视图 </summary>protected MemoryMappedViewAccessor MapView{get{if (_mmf == null){this.BuildFile();}if (_mapView == null){_mapView = _mmf.CreateViewAccessor();}return _mapView;}}private MemoryMappedViewStream _mapStream;/// <summary> 按循序访问的流 </summary>protected MemoryMappedViewStream MapStream{get{if (_mmf == null){this.BuildFile();}if (_mapStream == null){_mapStream = _mmf.CreateViewStream();}return _mapStream;}private set { _mapStream = value; }}#endregion/// <summary> 将 T 类型的结构从访问器读取到提供的引用中 </summary>public T GetPostion(long position){T structure;MapView.Read<T>(position, out structure);return structure;}/// <summary> 读取指定索引处结构 </summary>public T GetIndex(int index){long postion = index * this.MLeight;return this.GetPostion(postion);}/// <summary> 将 T 类型的结构从访问器读取到 T 类型的数组中 </summary>public T[] GetPostion(int count, long position = 0){T[] arr = new T[count];MapView.ReadArray<T>(position, arr, 0, count);return arr;}/// <summary> 将 T 类型的结构从访问器读取到 T 类型的数组中 </summary>public T[] GetAll(long position = 0){T[] arr = new T[this._count];MapView.ReadArray<T>(position, arr, 0, this._count);return arr;}/// <summary> 将一个结构写入访问器 </summary>public void SetPosition(long position, T structure){MapView.Write<T>(position, ref structure);}/// <summary> 写入指定索引处结构 </summary>public void SetIndex(int index, T structure){long postion = index * this.MLeight;this.SetPosition(postion, structure);}/// <summary> 将结构从 T 类型的数组写入访问器 </summary>public void SetPosition(long position, T[] arr){MapView.WriteArray<T>(position, arr, 0, arr.Length);}/// <summary> 将结构从 T 类型的数组写入访问器 </summary>public void SetAll(T[] arr){MapView.WriteArray<T>(0, arr, 0, arr.Length);}/// <summary> 将结构从 T 类型的数组写入访问器 </summary>public void SetAll(T t){T[] arr = new T[this.Count];this.Count.DoCountWhile(l => arr[l] = t);MapView.WriteArray<T>(0, arr, 0, this.Count);}/// <summary> 重置大小 </summary>public void ReSetSize(int count){this._count = count;this._size = count * this.MLeight;this.BuildFile();}}partial class MmfEntity<T> : IDisposable{#region - 构造函数 -public MmfEntity(string fileFullPath, int Tcount){this._file = fileFullPath;this._count = Tcount;this._size = Tcount * this.MLeight;this._name = Path.GetFileNameWithoutExtension(fileFullPath);this.BuildFile();}#endregion#region - 资源释放 -private bool _isDisposed = false;~MmfEntity(){Dispose(false);}public void Dispose(){Dispose(true);GC.SuppressFinalize(this);}protected virtual void Dispose(bool disposing){if (!_isDisposed){if (disposing){if (this._mapView != null) this._mapView.Dispose();if (this._mmf != null) this._mmf.Dispose();}this._isDisposed = true;}}#endregion}5、针对二维三维的定点结构访问
/// <summary> 二维存储结构 </summary>public class DxyMmfEntity<T> : MmfEntity<T> where T : struct{#region - 构造函数 -public DxyMmfEntity(string fileFullPath, int Tcount): base(fileFullPath, Tcount){}#endregionprivate int _x;/// <summary> X维数 </summary>public int X{get { return _x; }set { _x = value; }}private int _y;/// <summary> Y维数 </summary>public int Y{get { return _y; }set { _y = value; }}public void Set(int x, int y, T value) {this.SetIndex(TranFucntion(x, y), value);}/// <summary> 获取指定二维值 </summary>public T Get(int x, int y){return this.GetIndex(TranFucntion(x, y));}Func<int, int, int> tranFucntion;/// <summary> 设置指定二维值 </summary>public Func<int, int, int> TranFucntion{get { return (x, y) => y * this.X + x; }}}
/// <summary> 三维存储结构 </summary>public class DxyzMmfEntity<T> : MmfEntity<T> where T : struct{#region - 构造函数 -public DxyzMmfEntity(string fileFullPath, int x, int y, int z): base(fileFullPath, x * y * z){this.X = x;this.Y = y;this.Z = z;}/// <summary> 初始化方法 </summary>public void Init(int x, int y, int z){this.X = x;this.Y = y;this.Z = z;base.ReSetSize(x * y * z);}#endregionprivate int _x;/// <summary> X维数 </summary>public int X{get { return _x; }set { _x = value; }}private int _y;/// <summary> Y维数 </summary>public int Y{get { return _y; }set { _y = value; }}private int _z;/// <summary> Z方向维数 </summary>public int Z{get { return _z; }set { _z = value; }}public void Set(int x, int y, int z, T value){this.SetIndex(TranFucntion(x, y, z), value);}/// <summary> 获取指定二维值 </summary>public T Get(int x, int y, int z){return this.GetIndex(TranFucntion(x, y, z));}Func<int, int, int> tranFucntion;/// <summary> 设置指定二维值 </summary>public Func<int, int, int, int> TranFucntion{get { return (x, y, z) => z * this.X * this.Y + y * this.X + x; }}}6,测试用例
class Program{static void Main(string[] args){long offset = 0x10000000; // 256 megabyteslong length = 0x20000000; // 512 megabyteslong test = 800 * 1024;// 800 * 1024 * 1024;// 800MBDateTime time = DateTime.Now;Console.WriteLine("开始创建文件！");using (MmfEntity<int> mmf = new MmfEntity<int>(@"E:\ExtremelyLargeImage.data", 100)){for (int i = 0; i < 100; i++){mmf.SetIndex(i, i);}for (int i = 0; i < 100; i++){Console.WriteLine("执行：" + i + " 值:" + mmf.GetIndex(i));} } Console.WriteLine("完成！");Console.WriteLine("大小:" + test + "用时：" + (DateTime.Now - time).ToString());Console.Read();}
}7、MemoryMappedFile结构图
这篇关于封装：内存镜像文件（MemoryMappedFile）封装，一维二维三维定点访问的文章就介绍到这儿，希望我们推荐的文章对编程师们有所帮助！
