/* Subprogram:  convtime.c
       Author:  Shyam Lakshmin (lakshmin@cs.fsu.edu)
         Date:  July 13, 1999

   This function will convert a year/month/day/hour/minute time into a
   minute timestamp measured from 1-1-1980 00:00.  

   The function is passed the year/month/day/hour/minute time and the
   return value is the minute timestamp.  A value of -9999 is returned
   if an error is encountered.

   Based upon the subroutine convtime.f */

int convtime(int yr, int mon, int day, int hr, int min)
{
   int year[41] = {0, 527040, 1052640, 1578240, 2103840, 2630880,
       3156480, 3682080, 4207680, 4734720, 5260320, 5785920, 6311520,
       6838560, 7364160, 7889760, 8415360, 8942400, 9468000, 9993600,
       10519200, 11046240, 11571840, 12097440, 12623040, 13150080,
       13675680, 14201280, 14726880, 15253920, 15779520, 16305120,
       16830720, 17357760, 17883360, 18408960, 18934560, 19461600,
       19987200, 20512800, 21038400}; 
   int month[12] = {0, 44640, 84960, 129600, 172800, 217440, 260640,
       305280, 349920, 393120, 437760, 480960}; 
   int leap_mon[12] = {0, 44640, 86400, 131040, 174240, 218880, 262080,
       306720, 351360, 394560, 439200, 482400}; 
   int min_day = 1440; 
   int min_hr = 60; 

/* Test values to see if they fit valid ranges */

   if (yr < 1980 || yr > 2020) 
   {
      printf("ERROR ---- year out of range (1980-2020)");
      return -9999;
   }
   if (mon < 1 || mon > 12)
   {
      printf("ERROR ---- month out of range (1-12)");
      return -9999;
   }
   if (mon == 2) 
   {
      if ((yr%4 == 0) && (day < 1 || day > 29))
      {
         printf("ERROR ---- Feb. day out of range (1-29)");
         return -9999;
      }
      else if ((yr%4 != 0) && (day < 1 || day > 28))
      {
         printf("ERROR ---- Feb. day out of range (1-28)");
         return -9999;
      }
   }
   else if ((mon == 4) || (mon == 6) || (mon == 9) || (mon == 11)) 
   {
      if (day < 1 || day > 30)
      {
         printf("ERROR ---- day out of range (1-30)");
         return -9999;
      }
   }
   else
   {
      if (day < 1 || day > 31)
      {
         printf("ERROR ---- day out of range (1-31)");
         return -9999;
      }
   }
   if (hr < 0 || hr > 23)
   {
      printf("ERROR ---- hour out of range (0-23)");
      return -9999;
   }
   if (min < 0 || min > 60)
   {
      printf("ERROR ---- minute out of range (0-60)");
      return -9999;
   }

/* Convert time */

   if (yr%4 == 0)
      return year[yr-1980] + leap_mon[mon-1] + ((day-1)*min_day) + 
             (hr*min_hr) + min;
   else
      return year[yr-1980] + month[mon-1] + ((day-1)*min_day) +
             (hr*min_hr) + min;
}