C#中怎么快速内存拷贝
本篇文章给大家分享的是有关C#中怎么快速内存拷贝，小编觉得挺实用的，因此分享给大家学习，希望大家阅读完这篇文章后可以有所收获，话不多说，跟着小编一起来看看吧。
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首先你需要创建一个默认的Windows Forms应用程序工程，在窗体上放两个按钮，一个PictureBox 控件，因为我们将用图片来测试。
声明几个字段先：
string bitmapPath; Bitmap bmp, bmp2; BitmapData bmpd, bmpd2; byte[] buffer = null;
现在创建两个方法用来处理按钮的点击事件。
标准方法如下：
private void btnStandard_Click(object sender, EventArgs e) { using (OpenFileDialog ofd = new OpenFileDialog()) { if (ofd.ShowDialog() != System.Windows.Forms.DialogResult.OK) return; bitmapPath = ofd.FileName; } //open a selected image and create an empty image with the same size OpenImage(); //unlock for read and write images UnlockBitmap(); //copy data from one image to another by standard method CopyImage(); //lock images to be able to see them LockBitmap(); //lets see what we have pictureBox1.Image = bmp2; }快速方法如下：
private void btnFast_Click(object sender, EventArgs e) { using (OpenFileDialog ofd = new OpenFileDialog()) { if (ofd.ShowDialog() != System.Windows.Forms.DialogResult.OK) return; bitmapPath = ofd.FileName; } //open a selected image and create an empty image with the same size OpenImage(); //unlock for read and write images UnlockBitmap(); //copy data from one image to another with our fast method FastCopyImage(); //lock images to be able to see them LockBitmap(); //lets see what we have pictureBox1.Image = bmp2; }好的，现在我们有按钮并且也有了事件处理，下面来实现打开图片、锁定、解锁它们的方法，以及标准拷贝方法：
打开一个图片：
void OpenImage() { pictureBox1.Image = null; buffer = null; if (bmp != null) { bmp.Dispose(); bmp = null; } if (bmp2 != null) { bmp2.Dispose(); bmp2 = null; } GC.Collect(GC.MaxGeneration, GCCollectionMode.Forced); bmp = (Bitmap)Bitmap.FromFile(bitmapPath); buffer = new byte[bmp.Width * 4 * bmp.Height]; bmp2 = new Bitmap(bmp.Width, bmp.Height, bmp.Width * 4, PixelFormat.Format32bppArgb, Marshal.UnsafeAddrOfPinnedArrayElement(buffer, 0)); }锁定和解锁位图：
void UnlockBitmap() { bmpd = bmp.LockBits(new Rectangle(0, 0, bmp.Width, bmp.Height), ImageLockMode.ReadWrite, PixelFormat.Format32bppArgb); bmpd2 = bmp2.LockBits(new Rectangle(0, 0, bmp.Width, bmp.Height), ImageLockMode.ReadWrite, PixelFormat.Format32bppArgb); } void LockBitmap() { bmp.UnlockBits(bmpd); bmp2.UnlockBits(bmpd2); }从一个图片拷贝数据到另一个图片，并且显示测得的时间：
void CopyImage() { //start stopwatch Stopwatch sw = new Stopwatch(); sw.Start(); //copy-past data 10 times for (int i = 0; i < 10; i++) { System.Runtime.InteropServices.Marshal.Copy(bmpd.Scan0, buffer, 0, buffer.Length); } //stop stopwatch sw.Stop(); //show measured time MessageBox.Show(sw.ElapsedTicks.ToString()); }这就是标准快速拷贝方法。其实一点也不复杂，我们使用了知名的 System.Runtime.InteropServices.Marshal.Copy 方法。
以及又一个“中间方法（middle-method）”以用于快速拷贝逻辑：
void FastCopyImage() { FastMemCopy.FastMemoryCopy(bmpd.Scan0, bmpd2.Scan0, buffer.Length); }现在，来实现FastMemCopy类。下面是类的声明以及我们将会在类中使用到的一些类型：
internal static class FastMemCopy { [Flags] private enum AllocationTypes : uint { Commit = 0x1000, Reserve = 0x2000, Reset = 0x80000, LargePages = 0x20000000, Physical = 0x400000, TopDown = 0x100000, WriteWatch = 0x200000 } [Flags] private enum MemoryProtections : uint { Execute = 0x10, ExecuteRead = 0x20, ExecuteReadWrite = 0x40, ExecuteWriteCopy = 0x80, NoAccess = 0x01, ReadOnly = 0x02, ReadWrite = 0x04, WriteCopy = 0x08, GuartModifierflag = 0x100, NoCacheModifierflag = 0x200, WriteCombineModifierflag = 0x400 } [Flags] private enum FreeTypes : uint { Decommit = 0x4000, Release = 0x8000 } [UnmanagedFunctionPointerAttribute(CallingConvention.Cdecl)] private unsafe delegate void FastMemCopyDelegate(); private static class NativeMethods { [DllImport("kernel32.dll", SetLastError = true)] internal static extern IntPtr VirtualAlloc( IntPtr lpAddress, UIntPtr dwSize, AllocationTypes flAllocationType, MemoryProtections flProtect); [DllImport("kernel32")] [return: MarshalAs(UnmanagedType.Bool)] internal static extern bool VirtualFree( IntPtr lpAddress, uint dwSize, FreeTypes flFreeType); }现在声明方法本身：
public static unsafe void FastMemoryCopy(IntPtr src, IntPtr dst, int nBytes) { if (IntPtr.Size == 4) { //we are in 32 bit mode //allocate memory for our asm method IntPtr p = NativeMethods.VirtualAlloc( IntPtr.Zero, new UIntPtr((uint)x86_FastMemCopy_New.Length), AllocationTypes.Commit | AllocationTypes.Reserve, MemoryProtections.ExecuteReadWrite); try { //copy our method bytes to allocated memory Marshal.Copy(x86_FastMemCopy_New, 0, p, x86_FastMemCopy_New.Length); //make a delegate to our method FastMemCopyDelegate _fastmemcopy = (FastMemCopyDelegate)Marshal.GetDelegateForFunctionPointer(p, typeof(FastMemCopyDelegate)); //offset to the end of our method block p += x86_FastMemCopy_New.Length; //store length param p -= 8; Marshal.Copy(BitConverter.GetBytes((long)nBytes), 0, p, 4); //store destination address param p -= 8; Marshal.Copy(BitConverter.GetBytes((long)dst), 0, p, 4); //store source address param p -= 8; Marshal.Copy(BitConverter.GetBytes((long)src), 0, p, 4); //Start stopwatch Stopwatch sw = new Stopwatch(); sw.Start(); //copy-past all data 10 times for (int i = 0; i < 10; i++) _fastmemcopy(); //stop stopwatch sw.Stop(); //get message with measured time System.Windows.Forms.MessageBox.Show(sw.ElapsedTicks.ToString()); } catch (Exception ex) { //if any exception System.Windows.Forms.MessageBox.Show(ex.Message); } finally { //free allocated memory NativeMethods.VirtualFree(p, (uint)(x86_FastMemCopy_New.Length), FreeTypes.Release); GC.Collect(GC.MaxGeneration, GCCollectionMode.Forced); } } else if (IntPtr.Size == 8) { throw new ApplicationException("x64 is not supported yet!"); } }汇编代码被表示成带注释的字节数组：
private static byte[] x86_FastMemCopy_New = new byte[] { 0x90, //nop do nothing 0x60, //pushad store flag register on stack 0x95, //xchg ebp, eax eax contains memory address of our method 0x8B, 0xB5, 0x***, 0x01, 0x00, 0x00, //mov esi,[ebp][0000001***] get source buffer address 0x89, 0xF0, //mov eax,esi 0x83, 0xE0, 0x0F, //and eax,00F will check if it is 16 byte aligned 0x8B, 0xBD, 0x62, 0x01, 0x00, 0x00, //mov edi,[ebp][000000162] get destination address 0x89, 0xFB, //mov ebx,edi 0x83, 0xE3, 0x0F, //and ebx,00F will check if it is 16 byte aligned 0x8B, 0x8D, 0x6A, 0x01, 0x00, 0x00, //mov ecx,[ebp][00000016A] get number of bytes to copy 0xC1, 0xE9, 0x07, //shr ecx,7 divide length by 128 0x85, 0xC9, //test ecx,ecx check if zero 0x0F, 0x84, 0x1C, 0x01, 0x00, 0x00, //jz 000000146 ↓ copy the rest 0x0F, 0x18, 0x06, //prefetchnta [esi] pre-fetch non-temporal source data for reading 0x85, 0xC0, //test eax,eax check if source address is 16 byte aligned 0x0F, 0x84, 0x8B, 0x00, 0x00, 0x00, //jz 0000000C0 ↓ go to copy if aligned 0x0F, 0x18, 0x86, 0x80, 0x02, 0x00, 0x00, //prefetchnta [esi][000000280] pre-fetch more source data 0x0F, 0x10, 0x06, //movups xmm0,[esi] copy 16 bytes of source data 0x0F, 0x10, 0x4E, 0x10, //movups xmm1,[esi][010] copy more 16 bytes 0x0F, 0x10, 0x56, 0x20, //movups xmm2,[esi][020] copy more 0x0F, 0x18, 0x86, 0xC0, 0x02, 0x00, 0x00, //prefetchnta [esi][0000002C0] pre-fetch more 0x0F, 0x10, 0x5E, 0x30, //movups xmm3,[esi][030] 0x0F, 0x10, 0x66, 0x40, //movups xmm4,[esi][040] 0x0F, 0x10, 0x6E, 0x50, //movups xmm5,[esi][050] 0x0F, 0x10, 0x76, 0x60, //movups xmm6,[esi][060] 0x0F, 0x10, 0x7E, 0x70, //movups xmm7,[esi][070] we've copied 128 bytes of source data 0x85, 0xDB, //test ebx,ebx check if destination address is 16 byte aligned 0x74, 0x21, //jz 000000087 ↓ go to past if aligned 0x0F, 0x11, 0x07, //movups [edi],xmm0 past first 16 bytes to non-aligned destination address 0x0F, 0x11, 0x4F, 0x10, //movups [edi][010],xmm1 past more 0x0F, 0x11, 0x57, 0x20, //movups [edi][020],xmm2 0x0F, 0x11, 0x5F, 0x30, //movups [edi][030],xmm3 0x0F, 0x11, 0x67, 0x40, //movups [edi][040],xmm4 0x0F, 0x11, 0x6F, 0x50, //movups [edi][050],xmm5 0x0F, 0x11, 0x77, 0x60, //movups [edi][060],xmm6 0x0F, 0x11, 0x7F, 0x70, //movups [edi][070],xmm7 we've pasted 128 bytes of source data 0xEB, 0x1F, //jmps 0000000A6 ↓ continue 0x0F, 0x2B, 0x07, //movntps [edi],xmm0 past first 16 bytes to aligned destination address 0x0F, 0x2B, 0x4F, 0x10, //movntps [edi][010],xmm1 past more 0x0F, 0x2B, 0x57, 0x20, //movntps [edi][020],xmm2 0x0F, 0x2B, 0x5F, 0x30, //movntps [edi][030],xmm3 0x0F, 0x2B, 0x67, 0x40, //movntps [edi][040],xmm4 0x0F, 0x2B, 0x6F, 0x50, //movntps [edi][050],xmm5 0x0F, 0x2B, 0x77, 0x60, //movntps [edi][060],xmm6 0x0F, 0x2B, 0x7F, 0x70, //movntps [edi][070],xmm7 we've pasted 128 bytes of source data 0x81, 0xC6, 0x80, 0x00, 0x00, 0x00, //add esi,000000080 increment source address by 128 0x81, 0xC7, 0x80, 0x00, 0x00, 0x00, //add edi,000000080 increment destination address by 128 0x83, 0xE9, 0x01, //sub ecx,1 decrement counter 0x0F, 0x85, 0x7A, 0xFF, 0xFF, 0xFF, //jnz 000000035 ↑ continue if not zero 0xE9, 0x86, 0x00, 0x00, 0x00, //jmp 000000146 ↓ go to copy the rest of data 0x0F, 0x18, 0x86, 0x80, 0x02, 0x00, 0x00, //prefetchnta [esi][000000280] pre-fetch source data 0x0F, 0x28, 0x06, //movaps xmm0,[esi] copy 128 bytes from aligned source address 0x0F, 0x28, 0x4E, 0x10, //movaps xmm1,[esi][010] copy more 0x0F, 0x28, 0x56, 0x20, //movaps xmm2,[esi][020] 0x0F, 0x18, 0x86, 0xC0, 0x02, 0x00, 0x00, //prefetchnta [esi][0000002C0] pre-fetch more data 0x0F, 0x28, 0x5E, 0x30, //movaps xmm3,[esi][030] 0x0F, 0x28, 0x66, 0x40, //movaps xmm4,[esi][040] 0x0F, 0x28, 0x6E, 0x50, //movaps xmm5,[esi][050] 0x0F, 0x28, 0x76, 0x60, //movaps xmm6,[esi][060] 0x0F, 0x28, 0x7E, 0x70, //movaps xmm7,[esi][070] we've copied 128 bytes of source data 0x85, 0xDB, //test ebx,ebx check if destination address is 16 byte aligned 0x74, 0x21, //jz 000000112 ↓ go to past if aligned 0x0F, 0x11, 0x07, //movups [edi],xmm0 past 16 bytes to non-aligned destination address 0x0F, 0x11, 0x4F, 0x10, //movups [edi][010],xmm1 past more 0x0F, 0x11, 0x57, 0x20, //movups [edi][020],xmm2 0x0F, 0x11, 0x5F, 0x30, //movups [edi][030],xmm3 0x0F, 0x11, 0x67, 0x40, //movups [edi][040],xmm4 0x0F, 0x11, 0x6F, 0x50, //movups [edi][050],xmm5 0x0F, 0x11, 0x77, 0x60, //movups [edi][060],xmm6 0x0F, 0x11, 0x7F, 0x70, //movups [edi][070],xmm7 we've pasted 128 bytes of data 0xEB, 0x1F, //jmps 000000131 ↓ continue copy-past 0x0F, 0x2B, 0x07, //movntps [edi],xmm0 past 16 bytes to aligned destination address 0x0F, 0x2B, 0x4F, 0x10, //movntps [edi][010],xmm1 past more 0x0F, 0x2B, 0x57, 0x20, //movntps [edi][020],xmm2 0x0F, 0x2B, 0x5F, 0x30, //movntps [edi][030],xmm3 0x0F, 0x2B, 0x67, 0x40, //movntps [edi][040],xmm4 0x0F, 0x2B, 0x6F, 0x50, //movntps [edi][050],xmm5 0x0F, 0x2B, 0x77, 0x60, //movntps [edi][060],xmm6 0x0F, 0x2B, 0x7F, 0x70, //movntps [edi][070],xmm7 we've pasted 128 bytes of data 0x81, 0xC6, 0x80, 0x00, 0x00, 0x00, //add esi,000000080 increment source address by 128 0x81, 0xC7, 0x80, 0x00, 0x00, 0x00, //add edi,000000080 increment destination address by 128 0x83, 0xE9, 0x01, //sub ecx,1 decrement counter 0x0F, 0x85, 0x7A, 0xFF, 0xFF, 0xFF, //jnz 0000000C0 ↑ continue copy-past if non-zero 0x8B, 0x8D, 0x6A, 0x01, 0x00, 0x00, //mov ecx,[ebp][00000016A] get number of bytes to copy 0x83, 0xE1, 0x7F, //and ecx,07F get rest number of bytes 0x85, 0xC9, //test ecx,ecx check if there are bytes 0x74, 0x02, //jz 000000155 ↓ exit if there are no more bytes 0xF3, 0xA4, //rep movsb copy rest of bytes 0x0F, 0xAE, 0xF8, //sfence performs a serializing operation on all store-to-memory instructions 0x61, //popad restore flag register 0xC3, //retn return from our method to C# 0x00, 0x00, 0x00, 0x00, //source buffer address 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, //destination buffer address 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, //number of bytes to copy-past 0x00, 0x00, 0x00, 0x00 };以上就是C#中怎么快速内存拷贝，小编相信有部分知识点可能是我们日常工作会见到或用到的。希望你能通过这篇文章学到更多知识。更多详情敬请关注创新互联行业资讯频道。
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