C++ getline for when line endings are unknown

getlineSafe

// g++ -Wall getlineSafe.cpp -o getlineSafe -O

#include <string.h>
#include <iostream>
#include <fstream>
#include <cstdlib>

std::istream& getlineSafe(std::istream& is, std::string& t) {
    t.clear();

    // The characters in the stream are read one-by-one using a std::streambuf.
    // That is faster than reading them one-by-one using the std::istream.
    // Code that uses streambuf this way must be guarded by a sentry object.
    // The sentry object performs various tasks,
    // such as thread synchronization and updating the stream state.

    std::istream::sentry se(is, true);
    std::streambuf* sb = is.rdbuf();

    for (;;) {
        int c = sb->sbumpc();
		switch (c) {
			case '\n':
				return is;
			case '\r':
				if (sb->sgetc() == '\n') {
					sb->sbumpc();
				}
				return is;
			case EOF:
				// Also handle the case when the last line has no line ending
				if (t.empty()) {
					is.setstate(std::ios::eofbit);
				}
				return is;
			default:
				t += (char)c;
		}
    }
}

int main(int argc, char *argv[]) {
    std::string path;
    
    if (argc == 1) {
		std::cout << "Usage: ./safeLine filename" << std::endl;
		return EXIT_FAILURE;
	} else {
		path = argv[1];
	}

    std::ifstream ifs(path.c_str());
    if (!ifs) {
        std::cout << "Failed to open the file." << std::endl;
        return EXIT_FAILURE;
    }

    int n = 0;
    std::string t;
    while (!getlineSafe(ifs, t).eof()) {
        ++n;
    }
    ifs.close();
    std::cout << "The file contains " << n << " lines." << std::endl;
    return EXIT_SUCCESS;
}

Useful for when variously dealing with mac/unix/windows input files.
Taken from Stack Overflow.