#include <cstdlib>
#include <libscstring.hpp>
#include <stdexcept>
#include <iostream>
#include <fstream>

using namespace std;

static int check_file(istream& file) {
    string line;
    while (getline(file, line)) {
        if (!sc::is_valid_utf8(line)) return EXIT_FAILURE;
    }
    return EXIT_SUCCESS;
}

int main(int argc, char* argv[]) {
    try {
        if (argc == 1) {
            return check_file(cin);
        } else {
            ifstream file {argv[1]};
            if (!file) throw runtime_error {"could not open file"};
            return check_file(file);
        }
    } catch (const exception& ex) {
        cerr << "valid-utf8: " << ex.what() << '\n';
        return EXIT_FAILURE;
    }
}