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-rw-r--r--generic/checkargs.c85
-rw-r--r--generic/datecalc.c80
2 files changed, 165 insertions, 0 deletions
diff --git a/generic/checkargs.c b/generic/checkargs.c
new file mode 100644
index 0000000..e1c97be
--- /dev/null
+++ b/generic/checkargs.c
@@ -0,0 +1,85 @@
+/* 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 <stdlib.h>
+#include <string.h>
+
+int isDateArgument(char* dateString) {
+
+ const int MONTHS[] = {31,0,31,30,31,30,31,31,30,31,30,31};
+ int i, day, month, year;
+ char buffer[5];
+
+ /* 'today' is a valid date */
+ if (strcmp(dateString, "today") == 0)
+ return 1;
+
+ /* Numeric dates must be eight characters long */
+ if (8 != strlen(dateString))
+ return 0;
+
+ /* Check that the date is entirely formed of numbers */
+ for (i = 0; i < 8; i++) {
+ if (dateString[i] < '0' || dateString[i] > '9')
+ return 0;
+ }
+
+ /* Check that the date exists */
+ memset(buffer, 0, 5);
+ strncpy(buffer, dateString + 6, 2);
+ day = atoi(buffer);
+ strncpy(buffer, dateString + 4, 2);
+ month = atoi(buffer);
+ month -= 1;
+ strncpy(buffer, dateString, 4);
+ year = atoi(buffer);
+
+ /* Validate month */
+ if (month < 0 || month > 11)
+ return 0;
+
+ /* Validating dates is simple when the date does not fall into February */
+ if (1 != month) {
+ if (day < 1 || day > MONTHS[month])
+ return 0;
+ } else {
+ int feb = 28;
+
+ /* Februarys are a bit tougher issue */
+ if (0 == year % 4) {
+ if (0 == year % 100) {
+ if (0 == year % 400) {
+ feb = 29;
+ } else {
+ feb = 28;
+ }
+ } else {
+ feb = 29;
+ }
+ }
+ if (day < 1 || day > feb)
+ return 0;
+ }
+
+ /* Avoid user from using dates before 16000301, since those will result in
+ incorrect output */
+ if(16000301 > atoi(dateString))
+ return 0;
+
+ return 1;
+}
diff --git a/generic/datecalc.c b/generic/datecalc.c
new file mode 100644
index 0000000..e637b26
--- /dev/null
+++ b/generic/datecalc.c
@@ -0,0 +1,80 @@
+/* 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];
+ 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;
+
+ date[0] = date1;
+ date[1] = date2;
+
+ /* 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;
+}