An inherited class from otl_datime that makes it easy to work with dates in the otlv4 library

OtlDatetime.h

#ifndef OTLDATETIME_H 
#define OTLDATETIME_H
/*
 *  abstracao do otl_datetime
 */
#include <iomanip>
#include <otlv4.h>

class OtlDatetime : public otl_datetime 
{
private:
public:
    OtlDatetime(int ayear=1970,
	int amonth=1,
    int aday=1,
    int ahour=0,
    int aminute=0,
    int asecond=0,
    unsigned long afraction=0,
    int afrac_precision=0) :
    otl_datetime(ayear,
    amonth,
    aday,
    ahour,
    aminute,
    asecond,
    afraction,
    afrac_precision)
	{
    }

    OtlDatetime(const char *str, const char *fmt){
        *this = fromString(str, fmt);
    }

	~OtlDatetime(){}
    
    bool operator==(time_t in) { return (toTime_t() == in); };
    bool operator!=(time_t in) { return !(*this == in); };
    bool operator==(otl_datetime in){ return (year == in.year && month == in.month && day == in.day); }
    bool operator!=(otl_datetime in){ return !(*this == in); }
    bool operator<(otl_datetime in){ return ((year < in.year) || (year == in.year && month < in.month) || (year == in.year && month == in.month && day < in.day)); }
    bool operator>(otl_datetime in){ return ((year > in.year) || (year == in.year && month > in.month) || (year == in.year && month == in.month && day > in.day)); }
    bool operator<=(otl_datetime in){ return !(*this > in); }
    bool operator>=(otl_datetime in){ return !(*this < in); }
    
    OtlDatetime& operator=(const time_t &in){
        struct tm dt;
	    localtime_r(&in, &dt);
        *this = OtlDatetime(dt.tm_year + 1900, dt.tm_mon + 1, dt.tm_mday, dt.tm_hour, dt.tm_min, dt.tm_sec);
        return *this;
    }


    OtlDatetime operator ++ (int){ addDay(); return *this; }
    OtlDatetime operator -- (int){ subDay(); return *this; }

    OtlDatetime now(){
        *this = std::time(0);
        return *this;
    }

    int daysInMonth(){
        int days;
        if(month == 2){
            days = (((year % 4 == 0) && (year % 100 != 0)) || (year % 400 == 0)) ? 29 : 28;
        } else if(month == 4 || month == 6 || month == 9 || month == 11){
            days = 30;
        }else{
            days = 31;
        }
        return days;
    }   
    void addDay(){
       day++;
       if(day > daysInMonth()){
            addMonth();
            day = 1;
        }
    }
    void addDay(int n){
        for(int i = 1; i <= n; i++){
            addDay();
        }
    }  
    void subDay(){
        day--;
        if(day == 0){
            subMonth();
            day = daysInMonth();
        }
    }
    void subDay(int n){
        for(int i = 1; i <= n; i++){
            subDay();
        }
    } 
    void addMonth(){
        month++;
        if(month > 12){
            addYear();
            month = 1;
        }   
    }
    void addMonth(int n){
        for(int i = 1; i <= n; i++){
            addMonth();
        }
    }
    void subMonth(){
        month--;
        if(month == 0){
            subYear();
            month = 12;
        } 
    }
    void subMonth(int n){
        for(int i = 0; i <= n; i++){
            subMonth();
        }
    }
    void addYear(){
        year++;
    }
    void subYear(){
        year--;
    }
 	virtual bool isValid(){
        OtlDatetime empty;
        return (*this != empty); 
    }
    virtual time_t toTime_t(){
        struct tm tmp;
        tmp.tm_year = year - 1900;
	    tmp.tm_mon = month - 1;
	    tmp.tm_mday = day;
	    tmp.tm_hour = hour;
	    tmp.tm_min = minute;
	    tmp.tm_sec = second;
	    tmp.tm_isdst = 0; // desabilita horario de verao
        return mktime(&tmp);
    }
   
    virtual std::string toString(const char* fmt = "%F"){
        char buffer[128];
        time_t time = toTime_t();
        strftime(buffer, sizeof(buffer), fmt, localtime(&time));
        return std::string(buffer);
    }
    
    OtlDatetime fromString(const char *str, const char*fmt){
        if(*str){
            struct tm dt = { 0 };
            if(strptime(str, fmt, &dt) == NULL){
                return OtlDatetime();
            }
            return OtlDatetime(dt.tm_year + 1900, dt.tm_mon + 1, dt.tm_mday, dt.tm_hour, dt.tm_min, dt.tm_sec);
        }
        return OtlDatetime();
    }    
};

#endif