time parser

gistfile1.cpp

#include <string>
#include <sstream>
#include <cstdio>
#include <iostream>
#include <algorithm>
#include <stdexcept>
#include <vector>
#include <memory>
#include <chrono>
#include <thread>

namespace chr = std::chrono;

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

std::time_t parse_start_time (string const& duration_str)
{   
  try
  {
    return std::stoi(duration_str);
  }
  catch (std::invalid_argument const& exp) {}
  
  
  if (duration_str == "off")
  {
    
  }
  else if (duration_str == "now")
  {
    
  }
  
  std::stringstream ss(duration_str);
  string str;

  int seconds = 0;
  char type;
  int size;

  while (std::getline(ss, str, ' '))
  {
    remove_if(str.begin(), str.end(), isspace);
    if (str.size() == 0) continue;
    
    if (sscanf(str.c_str(), "%d%c", &size, &type) != 2)
    {
      throw std::invalid_argument("invalid duration format: " + str);
    }    
         if (type == 'w' || type == 'W') { seconds += size * 7 * 24 * 60 * 60; }
    else if (type == 'd' || type == 'D') { seconds += size * 24 * 60 * 60; }
    else if (type == 'h' || type == 'H') { seconds += size * 60 * 60; }
    else if (type == 'm' || type == 'M') { seconds += size * 60; }
    else if (type == 's' || type == 'S') { seconds += size; }
    else 
    {
      throw std::invalid_argument("invalid duration format: " + str);
    }
  }
  
  auto start_tp = chr::system_clock::now() - chr::seconds(seconds);
  retur chr::duration_cast<chr::seconds>(start_tp.time_since_epoch()).count();
}