Nick's Blog

In my current project I need a high performace xorcpy implemented in C. Here is my implementation to share and it is tested on my Xeon E5-2680 PC, it reaches almost 1.7GB/s.

#include <emmintrin.h>
...
__forceinline unsigned char* xorcpy(unsigned char* dst, const unsigned char* src, unsigned block_size)
{
    // Do the bulk of the copy a __m128i at a time, for faster speed
    __m128i* mto = (__m128i*)dst;
    const __m128i* mfrom = (__m128i*)(src);
    for(int i=(block_size / sizeof(__m128i) - 1); i>=0; i--)
    {
        __m128i xmm1 = _mm_loadu_si128(mto);
        __m128i xmm2 = _mm_loadu_si128(mfrom);

        xmm1 = _mm_xor_si128(xmm1, xmm2);     //  XOR 16 bytes
        _mm_storeu_si128(mto, xmm1);
        ++mto;
        ++mfrom;
    }

    // The rest bytes we have to do a byte a time though
    unsigned char* cto = (unsigned char*) mto;
    const unsigned char* cfrom = (const unsigned char*)mfrom;
    for(int i=(block_size % sizeof(__m128i)) - 1; i>=0; i--)
    {
        *cto++ ^= (*cfrom++);
    }
    return dst;
}

    
    #include 
    #include 

    using namespace Gdiplus;

    GdiplusStartupInput gdiplusStartupInput;
    ULONG_PTR gdiplusToken;
    GdiplusStartup(&gdiplusToken, &gdiplusStartupInput, NULL);
    ...
    IStream* pJpegStream = NULL;  //declare a memory stream
    CreateStreamOnHGlobal(NULL, TRUE, (LPSTREAM*)&pJpegStream);

    GpBitmap* pBitmap = NULL;
    unsigned char* dib = GetDib(); //get DIB or BMP data buffer
    DllExports::GdipCreateBitmapFromGdiDib((LPBITMAPINFO)dib, dib + sizeof(BITMAPINFOHEADER), &pBitmap);

    CLSID imageCLSID;
    GetEncoderClsid(L"image/jpeg", &imageCLSID);

    int jpegQuality = 100;

    EncoderParameters encoderParams; //setup jpeg encoder parameters
    encoderParams.Count = 1;
    encoderParams.Parameter[0].NumberOfValues = 1;
    encoderParams.Parameter[0].Guid = EncoderQuality;
    encoderParams.Parameter[0].Type = EncoderParameterValueTypeLong;
    encoderParams.Parameter[0].Value = &jpegQuality;

    //save jpeg into memory stream
    DllExports::GdipSaveImageToStream(pBitmap, pJpegStream, &imageCLSID, &encoderParams);

    LARGE_INTEGER lnOffset;
    lnOffset.QuadPart = 0;
    ULARGE_INTEGER ulnSize;
    //determine memory stream length
    pJpegStream->Seek(lnOffset, STREAM_SEEK_END, &ulnSize);
    pJpegStream->Seek(lnOffset, STREAM_SEEK_SET, NULL);
    int encodedBytes = ulnSize.QuadPart;
    
    //store jpeg memory stream into jpeg data buffer
    pJpegStream->Read(racBuf_, ulnSize.QuadPart, NULL);
    ...
    GdiplusShutdown(gdiplusToken);

// firewall.cpp : Defines the entry point for the console application.
//

#include "stdafx.h"
/********************************************************************++
Copyright (C) Microsoft. All Rights Reserved.

Abstract:
    This C++ file includes sample code for disabling Windows Firewall 
    per profile using the Microsoft Windows Firewall APIs.

--********************************************************************/
#include 
#include 
#include 

#pragma comment( lib, "ole32.lib" )

// Forward declarations
HRESULT     WFCOMInitialize(INetFwPolicy2** ppNetFwPolicy2);

int __cdecl main()
{
    HRESULT hrComInit = S_OK;
    HRESULT hr = S_OK;

    INetFwPolicy2 *pNetFwPolicy2 = NULL;

    // Initialize COM.
    hrComInit = CoInitializeEx(
                    0,
                    COINIT_APARTMENTTHREADED
                    );

    // Ignore RPC_E_CHANGED_MODE; this just means that COM has already been
    // initialized with a different mode. Since we don't care what the mode is,
    // we'll just use the existing mode.
    if (hrComInit != RPC_E_CHANGED_MODE)
    {
        if (FAILED(hrComInit))
        {
            printf("CoInitializeEx failed: 0x%08lxn", hrComInit);
            goto Cleanup;
        }
    }

    // Retrieve INetFwPolicy2
    hr = WFCOMInitialize(&pNetFwPolicy2);
    if (FAILED(hr))
    {
        goto Cleanup;
    }

    // Disable Windows Firewall for the Domain profile
    hr = pNetFwPolicy2->put_FirewallEnabled(NET_FW_PROFILE2_DOMAIN, FALSE);
    if (FAILED(hr))
    {
        printf("put_FirewallEnabled failed for Domain: 0x%08lxn", hr);
        goto Cleanup;
    }

    // Disable Windows Firewall for the Private profile
    hr = pNetFwPolicy2->put_FirewallEnabled(NET_FW_PROFILE2_PRIVATE, FALSE);
    if (FAILED(hr))
    {
        printf("put_FirewallEnabled failed for Private: 0x%08lxn", hr);
        goto Cleanup;
    }

    // Disable Windows Firewall for the Public profile
    hr = pNetFwPolicy2->put_FirewallEnabled(NET_FW_PROFILE2_PUBLIC, FALSE);
    if (FAILED(hr))
    {
        printf("put_FirewallEnabled failed for Public: 0x%08lxn", hr);
        goto Cleanup;
    }

Cleanup:

    // Release INetFwPolicy2
    if (pNetFwPolicy2 != NULL)
    {
        pNetFwPolicy2->Release();
    }

    // Uninitialize COM.
    if (SUCCEEDED(hrComInit))
    {
        CoUninitialize();
    }
   
    return 0;
}

// Instantiate INetFwPolicy2
HRESULT WFCOMInitialize(INetFwPolicy2** ppNetFwPolicy2)
{
    HRESULT hr = S_OK;

    hr = CoCreateInstance(
        __uuidof(NetFwPolicy2), 
        NULL, 
        CLSCTX_INPROC_SERVER, 
        __uuidof(INetFwPolicy2), 
        (void**)ppNetFwPolicy2);

    if (FAILED(hr))
    {
        printf("CoCreateInstance for INetFwPolicy2 failed: 0x%08lxn", hr);
        goto Cleanup;        
    }

Cleanup:
    return hr;
}