date.c: allow even more varied time formats

(and some added checks for truly non-sensical stuff)

diff --git a/date.c b/date.c
index 77a7958..5ee4984 100644 (file)
--- a/date.c
+++ b/date.c
@@ -157,75 +157,164 @@ static int match_alpha(const char *date, struct tm *tm, int *offset)
        return 0;
 }
 
-static int match_digit(char *date, struct tm *tm, int *offset)
+static int is_date(int year, int month, int day, struct tm *tm)
 {
-       char *end, c;
-       unsigned long num, num2, num3;
-
-       num = strtoul(date, &end, 10);
-
-       /* Time? num:num[:num] */
-       if (num < 24 && end[0] == ':' && isdigit(end[1])) {
-               tm->tm_hour = num;
-               num = strtoul(end+1, &end, 10);
-               if (num < 60) {
-                       tm->tm_min = num;
-                       if (end[0] == ':' && isdigit(end[1])) {
-                               num = strtoul(end+1, &end, 10);
-                               if (num < 61)
-                                       tm->tm_sec = num;
-                       }
+       if (month > 0 && month < 13 && day > 0 && day < 32) {
+               if (year == -1) {
+                       tm->tm_mon = month-1;
+                       tm->tm_mday = day;
+                       return 1;
                }
-               return end - date;
+               if (year >= 1970 && year < 2100) {
+                       year -= 1900;
+               } else if (year > 70 && year < 100) {
+                       /* ok */
+               } else if (year < 38) {
+                       year += 100;
+               } else
+                       return 0;
+
+               tm->tm_mon = month-1;
+               tm->tm_mday = day;
+               tm->tm_year = year;
+               return 1;
        }
+       return 0;
+}
+
+static int match_multi_number(unsigned long num, char c, char *date, char *end, struct tm *tm)
+{
+       long num2, num3;
+
+       num2 = strtol(end+1, &end, 10);
+       num3 = -1;
+       if (*end == c && isdigit(end[1]))
+               num3 = strtol(end+1, &end, 10);
 
-       /* Year? Day of month? Numeric date-string?*/
-       c = *end;
+       /* Time? Date? */
        switch (c) {
-       default:
-               if (num > 0 && num < 32) {
-                       tm->tm_mday = num;
+       case ':':
+               if (num3 < 0)
+                       num3 = 0;
+               if (num < 25 && num2 >= 0 && num2 < 60 && num3 >= 0 && num3 <= 60) {
+                       tm->tm_hour = num;
+                       tm->tm_min = num2;
+                       tm->tm_sec = num3;
                        break;
                }
-               if (num > 1900) {
-                       tm->tm_year = num - 1900;
-                       break;
-               }
-               if (num > 70) {
-                       tm->tm_year = num;
-                       break;
-               }
-               break;
+               return 0;
 
        case '-':
        case '/':
-               if (num && num < 32 && isdigit(end[1])) {
-                       num2 = strtoul(end+1, &end, 10);
-                       if (!num2 || num2 > 31)
+               if (num > 70) {
+                       /* yyyy-mm-dd? */
+                       if (is_date(num, num2, num3, tm))
                                break;
-                       if (num > 12) {
-                               if (num2 > 12)
-                                       break;
-                               num3 = num;
-                               num  = num2;
-                               num2 = num3;
-                       }
-                       tm->tm_mon = num - 1;
-                       tm->tm_mday = num2;
-                       if (*end == c && isdigit(end[1])) {
-                               num3 = strtoul(end+1, &end, 10);
-                               if (num3 > 1900)
-                                       num3 -= 1900;
-                               else if (num3 < 38)
-                                       num3 += 100;
-                               tm->tm_year = num3;
-                       }
+                       /* yyyy-dd-mm? */
+                       if (is_date(num, num3, num2, tm))
+                               break;
+               }
+               /* mm/dd/yy ? */
+               if (is_date(num3, num2, num, tm))
+                       break;
+               /* dd/mm/yy ? */
+               if (is_date(num3, num, num2, tm))
                        break;
+               return 0;
+       }
+       return end - date;
+}
+
+/*
+ * We've seen a digit. Time? Year? Date? 
+ */
+static int match_digit(char *date, struct tm *tm, int *offset)
+{
+       int n;
+       char *end;
+       unsigned long num;
+
+       num = strtoul(date, &end, 10);
+
+       /*
+        * Seconds since 1970? We trigger on that for anything after Jan 1, 2000
+        */
+       if (num > 946684800) {
+               time_t time = num;
+               if (gmtime_r(&time, tm))
+                       return end - date;
+       }
+
+       /*
+        * Check for special formats: num[:-/]num[same]num
+        */
+       switch (*end) {
+       case ':':
+       case '/':
+       case '-':
+               if (isdigit(end[1])) {
+                       int match = match_multi_number(num, *end, date, end, tm);
+                       if (match)
+                               return match;
+               }
+       }
+
+       /*
+        * None of the special formats? Try to guess what
+        * the number meant. We use the number of digits
+        * to make a more educated guess..
+        */
+       n = 0;
+       do {
+               n++;
+       } while (isdigit(date[n]));
+
+       /* Four-digit year or a timezone? */
+       if (n == 4) {
+               if (num <= 1200 && *offset == -1) {
+                       unsigned int minutes = num % 100;
+                       unsigned int hours = num / 100;
+                       *offset = hours*60 + minutes;
+               } else if (num > 1900 && num < 2100)
+                       tm->tm_year = num - 1900;
+               return n;
+       }
+
+       /*
+        * NOTE! We will give precedence to day-of-month over month or
+        * year numebers in the 1-12 range. So 05 is always "mday 5",
+        * unless we already have a mday..
+        *
+        * IOW, 01 Apr 05 parses as "April 1st, 2005".
+        */
+       if (num > 0 && num < 32 && tm->tm_mday < 0) {
+               tm->tm_mday = num;
+               return n;
+       }
+
+       /* Two-digit year? */
+       if (n == 2 && tm->tm_year < 0) {
+               if (num < 10 && tm->tm_mday >= 0) {
+                       tm->tm_year = num + 100;
+                       return n;
                }
+               if (num >= 70) {
+                       tm->tm_year = num;
+                       return n;
+               }
+       }
+
+       if (num > 0 && num < 32) {
+               tm->tm_mday = num;
+       } else if (num > 1900) {
+               tm->tm_year = num - 1900;
+       } else if (num > 70) {
+               tm->tm_year = num;
+       } else if (num > 0 && num < 13) {
+               tm->tm_mon = num-1;
        }
                
-       return end - date;
-                       
+       return n;
 }
 
 static int match_tz(char *date, int *offp)
@@ -233,10 +322,19 @@ static int match_tz(char *date, int *offp)
        char *end;
        int offset = strtoul(date+1, &end, 10);
        int min, hour;
+       int n = end - date - 1;
 
        min = offset % 100;
        hour = offset / 100;
 
+       /*
+        * Don't accept any random crap.. At least 3 digits, and
+        * a valid minute. We might want to check that the minutes
+        * are divisible by 30 or something too.
+        */
+       if (min >= 60 || n < 3)
+               return 0;
+
        offset = hour*60+min;
        if (*date == '-')
                offset = -offset;