C#+无unsafe的非托管大数组(large unmanaged array in c# without ‘unsafe‘ keyword)
+BIT祝威+悄悄在此留下版了个权的信息说：
C#申请一个大数组(Use a large array in C#)
在C#里，有时候我需要能够申请一个很大的数组、使用之、然后立即释放其占用的内存。
Sometimes I need to allocate a large array, use it and then release its memory space immediately.
由于在C#里提供的 int[] array = new int[1000000]; 这样的数组，其内存释放很难由程序员完全控制，在申请一个大数组后，程序可能会变得很慢。
If I use something like int[] array = new int[1000000]; , it will be difficult to release its memory space by programmer and the app probably runs slower and slower.
特别是在C#+OpenGL编程中，我在使用VAO/VBO时十分需要设计一个非托管的数组，比如在glBufferData时我希望可以使用下面的glBufferData：
Specially in C#+OpenGL routines when I‘m using VAO/VBO, I need an unmanaged array for glBufferData:
1 /// <summary>
2 /// 设置当前VBO的数据。
3 /// </summary>
4 /// <param name="target"></param>
5 /// <param name="data"></param>
6 /// <param name="usage"></param>
7 public static void glBufferData(uint target, UnmanagedArrayBase data, uint usage)
8 {
9 GetDelegateFor<glBufferData>()((uint)target,
10 data.ByteLength, // 使用非托管数组
11 data.Header, // 使用非托管数组
12 (uint)usage);
13 }
14 // ...
15 // glBufferData的声明
16 private delegate void glBufferData(uint target, int size, IntPtr data, uint usage);
而在指定VBO的数据时，可能是float、vec3等等类型：
And the content in VBO can be float, vec3 and any other structs.
1 /// <summary>
2 /// 金字塔的posotion array.
3 /// </summary>
4 static vec3[] positions = new vec3[]
5 {
6 new vec3(0.0f, 1.0f, 0.0f),
7 new vec3(-1.0f, -1.0f, 1.0f),
8 // ...
9 new vec3(-1.0f, -1.0f, 1.0f),
10 };
11 // Create a vertex buffer for the vertex data.
12 {
13 uint[] ids = new uint[1];
14 GL.GenBuffers(1, ids);
15 GL.BindBuffer(GL.GL_ARRAY_BUFFER, ids[0]);
16 // 使用vec3作为泛型的非托管数组的参数
17 UnmanagedArray<vec3> positionArray = new UnmanagedArray<vec3>(positions.Length);
18 for (int i = 0; i < positions.Length; i++)
19 {
20 // 使用this[i]这样的索引方式来读写非托管数组的元素
21 positionArray[i] = positions[i];
22 }
23 GL.BufferData(BufferDataTarget.ArrayBuffer, positionArray, BufferDataUsage.StaticDraw);
24 GL.VertexAttribPointer(positionLocation, 3, GL.GL_FLOAT, false, 0, IntPtr.Zero);
25 GL.EnableVertexAttribArray(positionLocation);
26 }
+BIT祝威+悄悄在此留下版了个权的信息说：
UnmanagedArray<T>
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<T> : no ‘unsafe‘ keyword, takes any struct as generic parameter, can be released anytime you want.
1 /// <summary>
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 /// <para>不能使用enum类型作为T。</para>
4 /// </summary>
5 /// <typeparam name="T">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。</typeparam>
6 public class UnmanagedArray<T> : UnmanagedArrayBase where T : struct
7 {
8
9 /// <summary>
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 /// </summary>
12 /// <param name="count"></param>
13 [MethodImpl(MethodImplOptions.Synchronized)]
14 public UnmanagedArray(int count)
15 : base(count, Marshal.SizeOf(typeof(T)))
16 {
17 }
18
19 /// <summary>
20 /// 获取或设置索引为<paramref name="index"/>的元素。
21 /// </summary>
22 /// <param name="index"></param>
23 /// <returns></returns>
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<T>(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<T>(value, pItem, true);// works in .net 4.5.1
45 }
46 }
47
48 /// <summary>
49 /// 按索引顺序依次获取各个元素。
50 /// </summary>
51 /// <returns></returns>
52 public IEnumerable<T> 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 /// <summary>
65 /// 非托管数组的基类。
66 /// </summary>
67 public abstract class UnmanagedArrayBase : IDisposable
68 {
69
70 /// <summary>
71 /// 数组指针。
72 /// </summary>
73 public IntPtr Header { get; private set; }
74
75 /// <summary>
76 /// 元素数目。
77 /// </summary>
78 public int Count { get; private set; }
79
80 /// <summary>
81 /// 单个元素的字节数。
82 /// </summary>
83 protected int elementSize;
84
85 /// <summary>
86 /// 申请到的字节数。（元素数目 * 单个元素的字节数）。
87 /// </summary>
88 public int ByteLength
89 {
90 get { return this.Count * this.elementSize; }
91 }
92
93
94 /// <summary>
95 /// 非托管数组。
96 /// </summary>
97 /// <param name="elementCount">元素数目。</param>
98 /// <param name="elementSize">单个元素的字节数。</param>
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<IDisposable> allocatedArrays = new List<IDisposable>();
112
113 /// <summary>
114 /// 立即释放所有<see cref="UnmanagedArray"/>。
115 /// </summary>
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 /// <summary>
134 /// Internal variable which checks if Dispose has already been called
135 /// </summary>
136 protected Boolean disposed;
137
138 /// <summary>
139 /// Releases unmanaged and - optionally - managed resources
140 /// </summary>
141 /// <param name="disposing"><c>true</c> to release both managed and unmanaged resources; <c>false</c> to release only unmanaged resources.</param>
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 /// <summary>
167 /// Performs application-defined tasks associated with freeing, releasing, or resetting unmanaged resources.
168 /// </summary>
169 public void Dispose()
170 {
171 this.Dispose(true);
172 GC.SuppressFinalize(this);
173 }
174
175 #endregion
176
177 }
UnmanagedArray
+BIT祝威+悄悄在此留下版了个权的信息说：
如何使用(How to use)
UnmanagedArray<T>使用方式十分简单，就像一个普通的数组一样：
Using UnamangedAray<T> is just like a normal array(int[], vec3[], etc.):
1 internal static void TypicalScene()
2 {
3 const int count = 100;
4
5 // 测试float类型
6 var floatArray = new UnmanagedArray<float>(count);
7 for (int i = 0; i < count; i++)
8 {
9 floatArray[i] = i;
10 }
11 for (int i = 0; i < count; i++)
12 {
13 var item = floatArray[i];
14 if (item != i)
15 { throw new Exception(); }
16 }
17
18 // 测试int类型
19 var intArray = new UnmanagedArray<int>(count);
20 for (int i = 0; i < count; i++)
21 {
22 intArray[i] = i;
23 }
24 for (int i = 0; i < count; i++)
25 {
26 var item = intArray[i];
27 if (item != i)
28 { throw new Exception(); }
29 }
30
31 // 测试bool类型
32 var boolArray = new UnmanagedArray<bool>(count);
33 for (int i = 0; i < count; i++)
34 {
35 boolArray[i] = i % 2 == 0;
36 }
37 for (int i = 0; i < count; i++)
38 {
39 var item = boolArray[i];
40 if (item != (i % 2 == 0))
41 { throw new Exception(); }
42 }
43
44 // 测试vec3类型
45 var vec3Array = new UnmanagedArray<vec3>(count);
46 for (int i = 0; i < count; i++)
47 {
48 vec3Array[i] = new vec3(i * 3 + 0, i * 3 + 1, i * 3 + 2);
49 }
50 for (int i = 0; i < count; i++)
51 {
52 var item = vec3Array[i];
53 var old = new vec3(i * 3 + 0, i * 3 + 1, i * 3 + 2);
54 if (item.x != old.x || item.y != old.y || item.z != old.z)
55 { throw new Exception(); }
56 }
57
58 // 测试foreach
59 foreach (var item in vec3Array.GetElements())
60 {
61 Console.WriteLine(item);
62 }
63
64 // 释放此数组占用的内存，这之后就不能再使用vec3Array了。
65 vec3Array.Dispose();
66
67 // 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。
68 UnmanagedArrayBase.FreeAll();
69 }
C#+无unsafe的非托管大数组(large unmanaged array in c# without 'unsafe' keyword)
时间： 2024-08-25 23:07:40