Win32: How to convert string to a date?

Question

In Windows, i want to parse a string as a date using an exact format string.

For example, given the string

"6/12/2010"

and the format:

"M/d/yyyy"

i want to convert the string to a date, while ensuring that the date matches the format.

i also need to be able to specify the Y2K sliding window, pivot. This means that if a 2-digit year is (correctly) entered, i will specify that number of years in the future i would consider the year to be. e.g.:

Two-digit Year    Pivot    Four-digit year
==============    =====    ===============
30                +0       1929
30                +18      1929
30                +19      1929
30                +20      2029
30                +21      2029
30                +100     2029

---

.NET already provides a DateTime.ParseExact function, which performs nearly exactly what i need:

date = DateTime.ParseExact("6/12/2010", 
         DateTimeFormatInfo.ShortDatePattern,
         Thread.CurrentThread.CurrentCulture);

Except i can't tell it the 100-year pivot value.

More examples:

String        Format Specifier        Date
"6/7/2029"   "M/d/yyyy"             6/7/2029
"6/7/29"     "M/d/yyyy"             (invalid, year too short)
"6/7/29"     "M/d/yy"               6/7/1929  (+0 pivot)
"6/7/29"     "M/d/yy"               6/7/2029  (+100 pivot
"6/7/29"     "M/d/yy"               6/7/2029  (+50 pivot)
"6/7/29"     "M/d/yy"               6/7/2029
"6/7/2029"   "M.d.yyyy"             (invalid, incorrect separators)
"6.7.2029"   "M.d.yyyy"             6/7/2029
"6.7.2029"   "M-d-yyyy"             (invalid, incorrect separators)
"6/7/2029"   "M/dd/yyyy"            (invalid, days requires leading zero)
"6/07/2029"  "M/dd/yyyy"            (invalid, days requires leading zero)    
"6/07/2029"  "MM/dd/yyyy"           (invalid, months requires leading zero)
"06/07/2029  "MM/dd/yyyy"           6/7/2029
"06/07/2029" "MM/d/yyyy"            (invalid, days should not have leading zero)
"06/7/2029"  "MM/d/yyyy"            6/7/2029

i know that Windows doesn't have native API to convert a string to a date.

Is there any established code out there that will convert a string to a date using a format specifier? Computers have been around for a while now; someone must have solved this problem already.

Here is a list of some sample format specifiers that you could be expected to see in Windows:

• M/d/yyyy
• M/d/yy
• M/dd/yyyy
• M/dd/yy
• MM/d/yyyy
• MM/d/yy
• MM/dd/yyyy
• MM/dd/yy
• d/M/yyyy
• d/M/yyy
• d/MM/yyyy
• d/MM/yy
• dd/M/yyyy
• dd/M/yy
• dd/MM/yyyy
• dd/MM/yy
• yyyy/M/d
• yy/M/d
• yyyy/MM/d
• yy/MM/d
• yyyy/MM/dd
• yy/MM/dd
• dd MM yyyy
• dd.MM.yyyy

See also

• MSDN: Day, Month, Year, and Era Format Pictures
• MSDN: LOCALE_SSHORTDATE
• Stackoverflow: Format string as date
• Stackoverflow: Parse a Date from a String in Win32
• MSDN: DateTime.ParseExact Method (String, String, IFormatProvider)
• Stackoverflow: Convert String To date in PHP