time.c

/*
     Copyright 2012-2014 Infinitycoding all rights reserved
     This file is part of the mercury c-library.

     The mercury c-library is free software: you can redistribute it and/or modify
     it under the terms of the GNU Lesser General Public License as published by
     the Free Software Foundation, either version 3 of the License, or
     any later version.

     The mercury c-library is distributed in the hope that it will be useful,
     but WITHOUT ANY WARRANTY; without even the implied warranty of
     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
     GNU Lesser General Public License for more details.

     You should have received a copy of the GNU Lesser General Public License
     along with the mercury c-library.  If not, see <http://www.gnu.org/licenses/>.
 */
/**
  @author Peter Hösch aka. BlitzBasic <phoesch@gmx.de>
*/

#include <time.h>


#include <string.h>
#include <stdlib.h>
#include <atoi.h>



const char weekday_name_short[WEEKDAY_NUMBER][MAX_WEEKDAY_NAME_SHORT_LENGTH] = {"Sun", "Mon", "Tue", "Wed", "Thu", "Fri", "Sat"};
const char weekday_name_long[WEEKDAY_NUMBER][MAX_WEEKDAY_NAME_LONG_LENGTH] = {"Sunday", "Monday", "Tuesday", "Wednesday", "Thursday", "Friday", "Saturday"};
const char month_name_short[MONTHS_NUMBER][MAX_MONTH_NAME_SHORT_LENGTH] = {"Jan", "Feb", "Mar", "Apr", "May", "June", "July", "Aug", "Sept", "Oct", "Nov", "Dec"};
const char month_name_long[MONTHS_NUMBER][MAX_MONTH_NAME_LONG_LENGTH] = {"January", "February", "March", "April", "May", "June", "July", "August", "September", "October", "November", "December"};

char static_string[STATIC_TIME_STRING_LENGTH];
struct tm static_tm;



time_t time(time_t *timer)
{
// TODO
    time_t t = 0;//TODO(time_t)linux_syscall(SYS_TIME, 0, 0, 0, 0, 0);

    if(timer != NULL)
        *timer = t;

    return t;
}


struct tm *localtime(const time_t *timer)
{
    return gmtolocal(gmtime(timer));
}


struct tm *gmtime(const time_t *timer)
{
    if(validtimestamp(timer) == INVALID_TIME)
        return NULL;

    int days = *timer / SECONDS_PER_DAY;
    int remaining_seconds = *timer % SECONDS_PER_DAY;

    // TODO

    static_tm.tm_sec = (remaining_seconds % SECONDS_PER_MINUTE);
    static_tm.tm_min = ((remaining_seconds % SECONDS_PER_HOUR) / SECONDS_PER_MINUTE);
    static_tm.tm_hour = (remaining_seconds / SECONDS_PER_HOUR);
    static_tm.tm_wday = (thursday + (days % DAYS_PER_WEEK));

    return &static_tm;
}


time_t mktime(struct tm *timer)
{
    if(validtm(timer) == INVALID_TIME)
        return -1;

    int year = 1900 + timer->tm_year;
    int leap_years = ((year - 1) - 1968) / 4 - ((year - 1) - 1900) / 100 + ((year - 1) - 1600) / 400;

    time_t timestamp = timer->tm_sec + (timer->tm_min * SECONDS_PER_MINUTE) + (timer->tm_hour * SECONDS_PER_HOUR) + (timer->tm_yday * SECONDS_PER_DAY) + (((year-1970)*DAYS_PER_YEAR+leap_years)*SECONDS_PER_DAY);

    if((timer->tm_mon >2) && (year%4==0 && (year%100!=0 || year%400==0)))
        timestamp += SECONDS_PER_DAY;

    return timestamp;
}


char *asctime(struct tm *timer)
{
    if(validtm(timer) == INVALID_TIME)
        return NULL;

    memset(static_string, ' ', sizeof(char) * STATIC_TIME_STRING_LENGTH);

    strncpy(&static_string[0], weekday_name_short[timer->tm_wday], 4);
    strncpy(&static_string[5], month_name_short[timer->tm_mon], 4);
    itoa(timer->tm_mday, &static_string[10], 10);
    itoa(timer->tm_hour, &static_string[13], 10);
    static_string[15] = ':';
    itoa(timer->tm_min, &static_string[16], 10);
    static_string[18] = ':';
    itoa(timer->tm_sec, &static_string[19], 10);
    itoa(timer->tm_year + 1900, &static_string[23], 10);
    static_string[27] = '\n';
    static_string[28] = '\0';

    return static_string;
}


char *ctime(const time_t *timer)
{
    return asctime(localtime(timer));
}


double difftime(time_t time1, time_t time0)
{
    return ((double)(time1 - time0));
}


clock_t clock()
{
    // TODO

    return -1;
}


size_t strftime(char *buffer, int maxchars, const char *format, struct tm *timer)
{
    // TODO

    return 0;
}


int validtm(const struct tm *timer)
{
    if(timer == NULL)
        return INVALID_TIME;

    if(timer->tm_sec < 0 || timer->tm_sec > 59 || timer->tm_min < 0 || timer->tm_min > 59 || timer->tm_hour < 0 || timer->tm_hour > 23 || timer->tm_mday < 1 || timer->tm_mday > 31 || timer->tm_year < 70 || timer->tm_wday < 0 || timer->tm_wday > 6 || timer->tm_yday < 0 || timer->tm_yday > 365 || (timer->tm_yday > 364 && (timer->tm_yday % 4 != 0 || (timer->tm_yday % 100 == 0 && (timer->tm_yday + 1900) % 400 != 0))))
        return INVALID_TIME;

    return VALID_TIME;
}


int validtimestamp(const time_t *timer)
{
    if(timer == NULL)
        return INVALID_TIME;

    if(timer < 0)
        return INVALID_TIME;

    return VALID_TIME;
}


struct tm *gmtolocal(struct tm *timer)
{
    if(validtm(timer) == INVALID_TIME)
        return NULL;

    // TODO

    return timer;
}


int gettimeofday(struct timeval *tp, struct timezone *tzp)
{
    if(tp)
    {
        tp->tv_sec = 0;//TODO//linux_syscall(SYS_TIME, 0, 0, 0, 0, 0);
        tp->tv_usec = 0; // kernel can't log usecs at the time of implementation
    }

    if(tzp)
    {
        tzp->tz_minuteswest = 23*60; // timeshift westwards from GMT -> timezone of middle europe
        tzp->tz_dsttime = 4; //
    }
    return 0;
}