1 files changed, 84 insertions, 0 deletions
diff --git a/lib/datecalc.c b/lib/datecalc.c
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+/*  datedif - calculates the difference in days between two dates
+ *  Copyright (C) 2000 Micael Widell     contact: xeniac@linux.nu
+ *
+ *  This program is free software; you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License as published by
+ *  the Free Software Foundation; either version 2 of the License, or
+ *  (at your option) any later version.
+ *
+ *  This program 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 General Public License for more details.
+ *
+ *  You should have received a copy of the GNU General Public License
+ *  along with this program; if not, write to the Free Software
+ *  Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
+ */
+
+#include <time.h>
+#include <stdlib.h>
+#include <string.h>
+
+
+/* Gaus's formula - days since 1.3.1600 (Gregorian calendar) */
+int days(register int n, register int m, register int y)
+{
+  register int cy;
+  if((m -= 2) <= 0){
+    m += 12; y--;
+  }
+  y -= 1600; cy = y/100;
+  return 365*y+y/4-cy+cy/4+367*m/12+n-31;
+}
+
+
+double dateCalc(char date1[], char date2[]){   
+  
+  /* Declare the needed variables */
+  char* date[2] = { date1, date2 };
+  struct tm *date_tm[2]; 
+  time_t date_time_t[2];
+  double dateDifference;
+  int isToday[2] = { 0, 0 };
+  char buffer[5];
+  int day[2], month[2], year[2], i;
+  
+  
+  /* If any of the arguments are "today", then include today's date in the
+     right variables */
+  for(i = 0; i < 2; i++){
+    if(!strcmp(date[i], "today")){
+      time(&date_time_t[i]); 
+      date_tm[i] = localtime(&date_time_t[i]);
+      day[i] = (*date_tm[i]).tm_mday;
+      month[i] = (*date_tm[i]).tm_mon + 1;
+      year[i] = (*date_tm[i]).tm_year + 1900;
+      isToday[i] = 1;
+    }
+  }
+  
+  /* Cut out the year, month and day from 8-digit datestrings */
+  for (i = 0; i < 2; i++){
+    if(!isToday[i]){
+      memset(buffer, 0, 5);
+      strncpy(buffer, &date[i][6], 2);
+      day[i] = atoi(buffer);
+      strncpy(buffer, &date[i][4], 2);
+      month[i] = atoi(buffer);
+      strncpy(buffer, date[i], 4);
+      year[i] = atoi(buffer);       
+    }
+  }
+  
+  /* Calculate the difference */
+  dateDifference = days(day[1], month[1], year[1]) - days(day[0], month[0], year[0]);
+  
+  return dateDifference;
+}
+
+
+
+
+
+