C#指针操作Marshal实例

        static void Main(string[] args)
        {
            byte[] a = new byte[]{0,0,0,0};
            byte[] b = new byte[] {1,2,3,4};
            IntPtr pt = Marshal.AllocHGlobal(a.Length);
            //从source数组的startIndex下标开始复制length个对象到ptr;
            Marshal.Copy(b,0,pt+0,b.Length);
            //从ptr复制length个对象到目标数组的，从目标数组的startIndex开始写入。
            Marshal.Copy((pt+1),a,1,2);
            unsafe
            {
                byte* pb = (byte*) pt;
                for (int i = 0; i < a.Length; i++)
                {
                    Console.WriteLine("/b:"+(*pb++) + "/a:" + a[i]);
                }
            }
            //释放非托管内存;
            Marshal.FreeHGlobal(pt);

            byte[] arBt = new byte[]{200,0,20,30,40,50,60,70,80,90,11,12,13,14,0x0f,199};
            IntPtr ptr = Marshal.AllocHGlobal(arBt.Length);
            //写入数据;
            Marshal.Copy(arBt, 0, ptr, arBt.Length);
            short[] arSt = new short[arBt.Length / sizeof(short)];
            int[] arInt = new int[arBt.Length / sizeof(int)];
            //复制为short数据;
            Marshal.Copy(ptr, arSt, 0, arSt.Length);
            //调整数据 此时arSt不变 下面的arInt改变;
            Marshal.WriteByte(ptr, 1, 9);
            Marshal.WriteByte(ptr, 10, (byte)(Marshal.ReadByte(ptr,10)*9));
            //复制为int数据;
            Marshal.Copy(ptr, arInt, 0, arInt.Length);
            for (int i = 0; i < arBt.Length; i++)
            {   
                Console.Write(arBt[i] + "-");
            }
            Console.WriteLine();
            for (int i = 0; i < arBt.Length; i++)
            {   
                Console.Write(Marshal.ReadByte(ptr,i) + "-");
            }
            Console.WriteLine();
            unsafe
            {　　//获取指定数组中指定索引处的元素的地址
                short* ps = (short*)Marshal.UnsafeAddrOfPinnedArrayElement(arSt, 0);
                byte[] tmp0 = BitConverter.GetBytes(*ps);
                Console.WriteLine(*ps+ "/" + (ushort)*ps+ ",byte>>>&0=" + tmp0[0] + ",&1=" + tmp0[1]);
　　　　　　　　　 //获取指定数组中指定索引处的元素的地址
                int* pi = (int*)Marshal.UnsafeAddrOfPinnedArrayElement(arInt, 0);
                byte[] tmp1 = BitConverter.GetBytes(*pi);
                Console.WriteLine(*pi + "/" + (uint)*pi + ",byte>>>&0=" + tmp1[0] + ",&1=" + tmp1[1] +",&2="+ tmp1[2] + ",&3=" + tmp1[3]);

                Console.WriteLine("-----short 2 byte-----");
                for (int i = 0; i < arSt.Length; i++)
                {
                    byte[] tmp = BitConverter.GetBytes(arSt[i]);
                    Console.WriteLine(arSt[i] + "/" + (ushort)arSt[i] + ",byte>>>&0=" + tmp[0] + ",&1=" + tmp[1]);
                }
                Console.WriteLine("-----int 2 byte-----");
                for (int i = 0; i < arInt.Length; i++)
                {
                    byte[] tmp = BitConverter.GetBytes(arInt[i]);
                    Console.WriteLine(arInt[i] + "/" + (uint)arInt[i] + ",byte>>>&0=" + tmp[0] + ",&1=" + tmp[1] + ",&2=" + tmp[2] + ",&3=" + tmp[3]);
                }
            }
            Marshal.FreeHGlobal(ptr);
　　　　　　　unsafe
            {
                Test tt = new Test();
                tt.t1 = 100;
                tt.t2 = true;
                tt.t3 = 6666;
                tt.t4 = 666666;
                tt.t6 = false;
                string s = "ABCD大师0X00";
                char[] chs = s.ToCharArray();
                char* block = stackalloc char[100];
                fixed (char* cpt = chs)
                {
                    for (int i = 0; i < chs.Length; i++)
                    {
                        tt.t5[i] = *(cpt + i);
                        block[i] = *(cpt + i);
                    }
                    Console.WriteLine(new string(tt.t5));
                }
            }
        }

        [StructLayout(LayoutKind.Sequential, Pack = 4)]
        public unsafe struct Test
        {
            public byte t1;
            public bool t2;
            public ushort t3;
            public int t4;
            //固定大小的缓冲区
            public fixed char t5[100];
            public bool t6;
        }