Question

当然,标题可能会误导。各位都希望你尽快研究以下两条幻灯片,并就如何尽可能改善业绩,避免过于夸张。守则只需要双赢。不幸的是,STL集装箱现在不是一个选择。

改为......

bool TextFile::Read(const char *pFilePath)
{
    bool            bSuccess    = false;
    std::ifstream   oFile(pFilePath, std::ios_base::in);

    if(oFile.is_open())
    {
        std::string stLineNow;
        std::size_t siLineLength;

        if(this->pLines)
        {
            this->Clear();
        }

        this->stFilePath = pFilePath;

        oFile.seekg(0, std::ios::end);
        this->pLines = new unsigned char *[static_cast<unsigned int> (oFile.tellg())];
        oFile.seekg(0, std::ios::beg);

        for(this->ulLinesCount = 0; std::getline(oFile, stLineNow).good(); this->ulLinesCount++)
        {
            siLineLength = stLineNow.length() + 1;
            this->pLines[this->ulLinesCount] = new unsigned char[siLineLength];
            memcpy(this->pLines[this->ulLinesCount], stLineNow.c_str(), siLineLength);
        }

        bSuccess = true;

        oFile.close();
    }

    return bSuccess;
}

......

bool TextFile::Save(const char *pFilePath)
{
    bool bSuccess = false;

    if(this->pLines)
    {
        std::ofstream oFile(pFilePath ? pFilePath : this->stFilePath, std::ios_base::out);

        if(oFile.is_open())
        {
            for(unsigned long ulPosition = 0; ulPosition < this->GetCount(); ulPosition++)
            {
                oFile << this->Get(ulPosition) <<  
 ;
            }

            bSuccess = true;

            oFile.close();
        }
    }

    return bSuccess;
}

......,请以假装形式。

提前感谢!

Answer 1

......我要做的是:

Use memory-mapped files. That s THE fastest way of reading files;
Then memcpy() all the file s contents in a new buffer;
Then run through the buffer once and count the newlines;
Make an array of as many pointers as there are newlines;
Run through the buffer another time, and this time:
- Replace the first byte of each newline with 0.
- Place a pointer to the start of each line in the pointer array.

Voilà !

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