C#+无unsafe的非托管大数组示例详解(large unmanaged array in c# without ‘unsafe’ keyword)

所以我设计了这样一个非托管的数组类型：无unsafe，可接收任何struct类型作为泛型参数，可随时释放内存。

So I designed this UnmangedArray : no 'unsafe' keyword, takes any struct as generic parameter, can be released anytime you want.

1 /// 

 2 /// 元素类型为sbyte, byte, char, short, ushort, int, uint, long, ulong, float, double, decimal, bool或其它struct的非托管数组。
 3 /// 不能使用enum类型作为T。
 4 /// 
 5 /// sbyte, byte, char, short, ushort, int, uint, long, ulong, float, double, decimal, bool或其它struct, 不能使用enum类型作为T。
 6 public class UnmanagedArray : UnmanagedArraybase where T : struct
 7 {
 8 
 9 /// 

 10 ///元素类型为sbyte, byte, char, short, ushort, int, uint, long, ulong, float, double, decimal, bool或其它struct的非托管数组。 
 11 /// 
 12 /// 
 13 [MethodImpl(MethodImplOptions.Synchronized)]
 14 public UnmanagedArray(int count)
 15 : base(count, Marshal.SizeOf(typeof(T)))
 16 {
 17 }
 18 
 19 /// 

 20 /// 获取或设置索引为的元素。
 21 /// 
 22 /// 
 23 /// 
 24 public T this[int index]
 25 {
 26 get
 27 {
 28  if (index < 0 || index >= this.Count)
 29  throw new IndexOutOfRangeException("index of UnmanagedArray is out of range");
 30 
 31  var pItem = this.Header + (index * elementSize);
 32  //var obj = Marshal.PtrToStructure(pItem, typeof(T));
 33  //T result = (T)obj;
 34  T result = Marshal.PtrToStructure(pItem);// works in .net 4.5.1
 35  return result;
 36 }
 37 set
 38 {
 39  if (index < 0 || index >= this.Count)
 40  throw new IndexOutOfRangeException("index of UnmanagedArray is out of range");
 41  
 42  var pItem = this.Header + (index * elementSize);
 43  //Marshal.StructureToPtr(value, pItem, true);
 44  Marshal.StructureToPtr(value, pItem, true);// works in .net 4.5.1
 45 }
 46 }
 47 
 48 /// 

 49 /// 按索引顺序依次获取各个元素。
 50 /// 
 51 /// 
 52 public IEnumerable GetElements()
 53 {
 54 if (!this.disposed)
 55 {
 56  for (int i = 0; i < this.Count; i++)
 57  {
 58  yield return this[i];
 59  }
 60 }
 61 }
 62 }
 63 
 64 /// 

 65 /// 非托管数组的基类。
 66 /// 
 67 public abstract class UnmanagedArraybase : IDisposable
 68 {
 69 
 70 /// 

 71 /// 数组指针。
 72 /// 
 73 public IntPtr Header { get; private set; }
 74 
 75 /// 

 76 /// 元素数目。
 77 /// 
 78 public int Count { get; private set; }
 79 
 80 /// 

 81 /// 单个元素的字节数。
 82 /// 
 83 protected int elementSize;
 84 
 85 /// 

 86 /// 申请到的字节数。（元素数目 * 单个元素的字节数）。
 87 /// 
 88 public int ByteLength
 89 {
 90 get { return this.Count * this.elementSize; }
 91 }
 92 
 93 
 94 /// 

 95 /// 非托管数组。
 96 /// 
 97 /// 元素数目。
 98 /// 单个元素的字节数。
 99 [MethodImpl(MethodImplOptions.Synchronized)]
100 protected UnmanagedArraybase(int elementCount, int elementSize)
101 {
102 this.Count = elementCount;
103 this.elementSize = elementSize;
104 
105 int memSize = elementCount * elementSize;
106 this.Header = Marshal.AllocHGlobal(memSize);
107 
108 allocatedArrays.Add(this);
109 }
110 
111 private static readonly List allocatedArrays = new List();
112 
113 /// 

114 /// 立即释放所有。
115 /// 
116 [MethodImpl(MethodImplOptions.Synchronized)]
117 public static void FreeAll()
118 {
119 foreach (var item in allocatedArrays)
120 {
121  item.Dispose();
122 }
123 allocatedArrays.Clear();
124 }
125 
126 ~UnmanagedArraybase()
127 {
128 Dispose();
129 }
130 
131 #region IDisposable Members
132 
133 /// 

134 /// Internal variable which checks if Dispose has already been called
135 /// 
136 protected Boolean disposed;
137 
138 /// 

139 /// Releases unmanaged and - optionally - managed resources
140 /// 
141 /// true to release both managed and unmanaged resources; false to release only unmanaged resources.
142 protected void Dispose(Boolean disposing)
143 {
144 if (disposed)
145 {
146  return;
147 }
148 
149 if (disposing)
150 {
151  //Managed cleanup code here, while managed refs still valid
152 }
153 //Unmanaged cleanup code here
154 IntPtr ptr = this.Header;
155 
156 if (ptr != IntPtr.Zero)
157 {
158  this.Count = 0;
159  this.Header = IntPtr.Zero;
160  Marshal.FreeHGlobal(ptr);
161 }
162 
163 disposed = true;
164 }
165 
166 /// 

167 /// Performs application-defined tasks associated with freeing, releasing, or resetting unmanaged resources.
168 /// 
169 public void Dispose()
170 {
171 this.Dispose(true);
172 GC.SuppressFinalize(this);
173 }
174 
175 #endregion
176  
177 }

UnmanagedArray

UnmanagedArray使用方式十分简单，就像一个普通的数组一样：

Using UnamangedAray is just like a normal array(int[], vec3[], etc.):

internal static void TypicalScene()
 {
 const int count = 100;

 // 测试float类型
 var floatArray = new UnmanagedArray(count);
 for (int i = 0; i < count; i++)
 {
 floatArray[i] = i;
 }
 for (int i = 0; i < count; i++)
 {
 var item = floatArray[i];
 if (item != i)
 { throw new Exception(); }
 }

 // 测试int类型
 var intArray = new UnmanagedArray(count);
 for (int i = 0; i < count; i++)
 {
 intArray[i] = i;
 }
 for (int i = 0; i < count; i++)
 {
 var item = intArray[i];
 if (item != i)
 { throw new Exception(); }
 }

 // 测试bool类型
 var boolArray = new UnmanagedArray(count);
 for (int i = 0; i < count; i++)
 {
 boolArray[i] = i % 2 == 0;
 }
 for (int i = 0; i < count; i++)
 {
 var item = boolArray[i];
 if (item != (i % 2 == 0))
 { throw new Exception(); }
 }

 // 测试vec3类型
 var vec3Array = new UnmanagedArray(count);
 for (int i = 0; i < count; i++)
 {
 vec3Array[i] = new vec3(i * 3 + 0, i * 3 + 1, i * 3 + 2);
 }
 for (int i = 0; i < count; i++)
 {
 var item = vec3Array[i];
 var old = new vec3(i * 3 + 0, i * 3 + 1, i * 3 + 2);
 if (item.x != old.x || item.y != old.y || item.z != old.z)
 { throw new Exception(); }
 }

 // 测试foreach
 foreach (var item in vec3Array.GetElements())
 {
 Console.WriteLine(item);
 }

 // 释放此数组占用的内存，这之后就不能再使用vec3Array了。
 vec3Array.Dispose();

 // 立即释放所有非托管数组占用的内存，这之后就不能再使用上面申请的数组了。
 UnmanagedArraybase.FreeAll();
 }

public static class UnmanagedArrayHelper
 {
 ///// 

 ///// 错误 1 无法获取托管类型(“T”)的地址和大小，或无法声明指向它的指针
 ///// 
 ///// 
 ///// 
 ///// 
 //public static unsafe T* FirstElement(this UnmanagedArray array) where T : struct
 //{
 // var header = (void*)array.Header;
 // return (T*)header;
 //}

 /// 

 /// 获取非托管数组的第一个元素的地址。
 /// 
 /// 
 /// 
 public static unsafe void* FirstElement(this UnmanagedArraybase array)
 {
 var header = (void*)array.Header;

 return header;
 }

 public static unsafe void* LastElement(this UnmanagedArraybase array)
 {
 var last = (void*)(array.Header + (array.ByteLength - array.ByteLength / array.Length));

 return last;
 }

 /// 

 /// 获取非托管数组的最后一个元素的地址再向后一个单位的地址。
 /// 
 /// 
 /// 
 public static unsafe void* TailAddress(this UnmanagedArraybase array)
 {
 var tail = (void*)(array.Header + array.ByteLength);

 return tail;
 }
 }

public static void TypicalScene()
 {
 int length = 1000000;
 UnmanagedArray array = new UnmanagedArray(length);
 UnmanagedArray array2 = new UnmanagedArray(length);

 long tick = DateTime.Now.Ticks;
 for (int i = 0; i < length; i++)
 {
 array[i] = i;
 }
 long totalTicks = DateTime.Now.Ticks - tick;

 tick = DateTime.Now.Ticks;
 unsafe
 {
 int* header = (int*)array2.FirstElement();
 int* last = (int*)array2.LastElement();
 int* tailAddress = (int*)array2.TailAddress();
 int value = 0;
 for (int* ptr = header; ptr <= last; ptr++)
 {
  *ptr = value++;
 }
 }
 long totalTicks2 = DateTime.Now.Ticks - tick;
 Console.WriteLine("ticks: {0}, {1}", totalTicks, totalTicks2);// unsafe method works faster.

 for (int i = 0; i < length; i++)
 {
 if (array[i] != i)
 {
  Console.WriteLine("something wrong here");
 }
 if (array2[i] != i)
 {
  Console.WriteLine("something wrong here");
 }
 }

 array.Dispose();
 array2.Dispose();
 }

unsafe
 {
  vec3* header = (vec3*)vec3Array.FirstElement();
  vec3* last = (vec3*)vec3Array.LastElement();
  vec3* tailAddress = (vec3*)vec3Array.TailAddress();
  int i = 0;
  for (vec3* ptr = header; ptr <= last; ptr++)
  {
  *ptr = new vec3(i * 3 + 0, i * 3 + 1, i * 3 + 2);
  i++;
  }
  i = 0;
  for (vec3* ptr = header; ptr <= last; ptr++, i++)
  {
  var item = *ptr;
  var old = new vec3(i * 3 + 0, i * 3 + 1, i * 3 + 2);
  if (item.x != old.x || item.y != old.y || item.z != old.z)
  { throw new Exception(); }
  }
 }

1 /// 

 2 /// Represents a 4x4 matrix.
 3 /// 
 4 [StructLayout(LayoutKind.Sequential, CharSet = CharSet.Ansi, Size = 4 * 4 * 4)]
 5 public struct mat4
 6 {
 7 /// 

 8 /// Gets or sets the  column at the specified index.
 9 /// 
10 /// 
11 /// The  column.
12 /// 
13 /// The column index.
14 /// The column at index .
15 public vec4 this[int column]
16 {
17 get { return cols[column]; }
18 set { cols[column] = value; }
19 }
20 
21 /// 

22 /// Gets or sets the element at  and .
23 /// 
24 /// 
25 /// The element at  and .
26 /// 
27 /// The column index.
28 /// The row index.
29 /// 
30 /// The element at  and .
31 /// 
32 public float this[int column, int row]
33 {
34 get { return cols[column][row]; }
35 set { cols[column][row] = value; }
36 }
37 
38 /// 

39 /// The columms of the matrix.
40 /// 
41 [MarshalAs(UnmanagedType.ByValArray, SizeConst = 4)]
42 private vec4[] cols;
43 }
44 
45 /// 

46 /// Represents a four dimensional vector.
47 /// 
48 [StructLayout(LayoutKind.Sequential, CharSet = CharSet.Ansi, Size = 4 * 4)]
49 public struct vec4
50 {
51 public float x;
52 public float y;
53 public float z;
54 public float w;
55 
56 public float this[int index]
57 {
58 get
59 {
60  if (index == 0) return x;
61  else if (index == 1) return y;
62  else if (index == 2) return z;
63  else if (index == 3) return w;
64  else throw new Exception("Out of range.");
65 }
66 set
67 {
68  if (index == 0) x = value;
69  else if (index == 1) y = value;
70  else if (index == 2) z = value;
71  else if (index == 3) w = value;
72  else throw new Exception("Out of range.");
73 }
74 }
75 }

mat4

mat4 matrix = glm.scale(mat4.identity(), new vec3(2, 3, 4));

 var size = Marshal.SizeOf(typeof(mat4));
 size = Marshal.SizeOf(matrix);

 UnmanagedArray array = new UnmanagedArray(1);
 array[0] = matrix;

 mat4 newMatirx = array[0]; // newMatrix should be equal to matrix

 array.Dispose();