Skip to main content
1 of 1
Matthew
  • 301
  • 1
  • 5

Stop allocating memory:

  • Don't copy vectors around, pass by const ref instead
  • Don't make new strings when a string_view will do
  • Don't make new vectors when you can reuse the old one
  • Don't make a string from a char*, just to turn it back into a char* (this one is very minor since you only do it once)
  • Output directly to avoid creating a temporary string in makeCSVLine

With all that, here's what I came up with:

#include <fstream>
#include <string>
#include <string_view>
#include <vector>

using std::string;
using std::string_view;
using std::vector;

void splitStr(string_view line, const char delimiter, vector<string_view>& splitLine)
{
    splitLine.clear();
    for(;;) {
        std::size_t pos = line.find(delimiter);
        if (pos == string_view::npos) {
            splitLine.push_back(line);
            return;
        }

        splitLine.push_back(line.substr(0, pos));
        line = line.substr(pos+1, string_view::npos);
    }
}

template<typename T>
void makeCSVLine(T& out, const vector<string_view>& splitLine)
{
    out <<
        splitLine[0] << ',' <<
        splitLine[1] << ',' <<
        splitLine[3] << ',' <<
        splitLine[4] << ',' <<
        splitLine[5] << ',' <<
        splitLine[6] << ',' <<
        splitLine[10] << ',' <<
        splitLine[9] << ',' <<
        splitLine[11] << ',' <<
        splitLine[7] << ',' <<
        splitLine[32] << '\n';
}

int main(int argc, char* argv[])
{
    if(argc < 3)
    {
        exit(EXIT_SUCCESS);
    }

    const char* inPath = argv[1];
    const char* outPath = argv[2];

    std::ifstream inFile;
    std::ofstream outFile;

    inFile.open(inPath);
    outFile.open(outPath);

    vector<string_view> split;
    string line;
    while(std::getline(inFile, line))
    {
        splitStr(line, ';', split);
        if(split[3][0] == 'E' || split[3][0] == 'T')
        {
            makeCSVLine(outFile, split);
        }
    }
    inFile.close();
    outFile.close();
}
Matthew
  • 301
  • 1
  • 5