main.cpp

#include <iostream>

#include <string>

#include <ctime>
#include <sstream>
#include <locale>
#include <iomanip>

#define ARTIST_PREFIX 20
#define TRACK_PREFIX  19
#define TIME_PREFIX   14
#define POSTFIX        2

struct lastFmEntry {
    std::string artist;
    std::string title;
    std::string album = "single";
    int track = 1;
    long timestamp;
    int length = 300;
    char noIdea = 'P';
};

int main() {
    std::tm t = {};
    lastFmEntry currentEntry;

    bool newEntry = true;

    std::string line;
    while (std::getline(std::cin, line)) {
        if (newEntry) {
            currentEntry.artist = "";
            currentEntry.title = "";
            currentEntry.timestamp = 0;
            newEntry = false;
        }

        if (line.find("artistName") != std::string::npos) {
            std::string artist = line.substr(ARTIST_PREFIX, line.size() - ARTIST_PREFIX - POSTFIX);
            if (artist.find(',') != std::string::npos) {
                currentEntry.artist = artist.substr(0, artist.find(','));
            } else currentEntry.artist = artist;
        } else if (line.find("track") != std::string::npos) {
            currentEntry.title = line.substr(TRACK_PREFIX, line.size() - TRACK_PREFIX - POSTFIX);
        } else if (line.find("time") != std::string::npos) {
            // convert human readable time to unix gmt timestamp
            std::istringstream ss(line.substr(TIME_PREFIX, line.size() - TIME_PREFIX - POSTFIX + 1));
            ss >> std::get_time(&t, "%Y-%m-%d %H:%M:%S");

            currentEntry.timestamp = std::mktime(&t);

            if (1528715908 < currentEntry.timestamp && currentEntry.timestamp < 1528960251) {
                std::cout <<
                          "a = " << currentEntry.artist    << "\n" <<
                          "t = " << currentEntry.title     << "\n" <<
                          "b = " << currentEntry.album     << "\n" <<
                          "n = " << currentEntry.track     << "\n" <<
                          "i = " << currentEntry.timestamp << "\n" <<
                          "l = " << currentEntry.length    << "\n" <<
                          "o = " << currentEntry.noIdea    << "\n\n";
            }
        }
    }

    return 0;
}