ParseExact - parsing a date with a given format in C++ / MFC

BadJerry

Hello, I need a function that would do a parse exact on a CString - given a format - and return a date (or an exception!) Eg COleDateTime timParsed; timParsed.ParseExact("2002 10 3","yyyy mm d"); I am aware of ParseDateTime... but I need something where you actually specify the expected format! And I knoe ParseExact is in .net but hey I am stuck in the nineties! Any idea? Thanks! Jerry

Jochen Arndt

You may use time_from_string() from boost::posix_time, port the OpenSource code of the BSD strptime() function, or write a parser yourself (e.g. using sscanf()).

Lost User

I have had some success in the past using strftime()[^].

One of these days I'm going to think of a really clever signature.

BadJerry

Thanks Jochen And Richard, Yes I used an OpenSource version of strptime() that I found here: http://plibc.sourceforge.net/doxygen/strptime_8c-source.html[^]- and I have transformef the char(s) into TCHAR, added _T, etc.... and I ave written this:

{
...
CString strFormatCpp = TranslateFormatDate(strFormatVB);

tm timeDate;
memset(&timeDate,0,sizeof(tm ));
TCHAR \* pRes = strptime (strMyDate, strFormatCpp, &timeDate);
			
if ( pRes != NULL )
{
	COleDateTime oleDate;
	oleDate.SetDateTime(1900 + timeDate.tm\_year,timeDate.tm\_mon+1,timeDate.tm\_mday,timeDate.tm\_hour,timeDate.tm\_min,timeDate.tm\_sec);

}

}

CString TranslateFormatDate(const CString & strFormat)
{
CString strResult;
int nChar = 0;
while ( nChar < strFormat.GetLength() )
{
switch ( strFormat[nChar] )
{
case 'A':
if ( MatchFormatKey(_T("AMPM"),_T("%p"),strFormat, nChar,strResult) )
continue;
break;
case 'a':
if ( MatchFormatKey(_T("ampm"),_T("%p"),strFormat, nChar,strResult) ) // Lower does not exist in C++?
continue;
case 'y':
if ( MatchFormatKey(_T("yyyy"),_T("%Y"),strFormat, nChar,strResult) )
continue;
if ( MatchFormatKey(_T("yy"),_T("%y"),strFormat, nChar,strResult) )
continue;
break;
case 'M':
if ( MatchFormatKey(_T("MMMM"),_T("%B"),strFormat, nChar,strResult) )
continue;
if ( MatchFormatKey(_T("MMM"),_T("%b"),strFormat, nChar,strResult) )
continue;
if ( MatchFormatKey(_T("MM"),_T("%m"),strFormat, nChar,strResult) )
continue;
if ( MatchFormatKey(_T("M"),_T("%#m"),strFormat, nChar,strResult) )
continue;
break;
case 'd':
if ( MatchFormatKey(_T("dddd"),_T("%A"),strFormat, nChar,strResult) )
continue;
if ( MatchFormatKey(_T("ddd"),_T("%a"),strFormat, nChar,strResult) )
continue;
if ( MatchFormatKey(_T("dd"),_T("%d"),strFormat, nChar,strResult) )
continue;
if ( MatchFormatKey(_T("d"),_T("%#d"),strFormat, nChar,strResult) )
continue;
break;
case 'h':
if ( MatchFormatKey(_T("hh"),_T("%I"),strFormat, nChar,strResult) )
continue;
if ( MatchFormatKey(_T("h"),_T("%#I"),strFormat, nChar,strResult) )
continue;
break;
case 'H':
if ( MatchFormatKey(_T("HH"),_T("%H"),strFormat, nChar,strResult) )
continue;
if ( MatchFormatKey(_T("H"),_T("%#H"),strFormat,

Software_Developer

Richard pointed out using strftime( ) . it is standard C.

#include
#include

int main ()
{
time_t rawtime;
struct tm * timeinfo;
char buffer [80];

time ( &rawtime );
timeinfo = localtime ( &rawtime );

strftime (buffer,80,"%Y %m %d ",timeinfo);

puts (buffer);

return 0;
}

BadJerry

Yes but I want to parse not to format! Thanks! Jerry

Lost User

My apologies, I got mixed up, and cannot for the life of me recall the function that does the parsing. [edit] It's strptime() which, unfortunately, is not available in Windows, so you will need to get a copy of an open source version from somewhere. [/edit]

One of these days I'm going to think of a really clever signature.

krmed

You can still use the ParseDateTime, but you need to set the format first. Here's what I've done... First, get the current format using

GetLocaleInfo(m\_LCID, LOCALE\_SSHORTDATE, m\_csOriginalSDateFormat.GetBuffer(MAX\_PATH + 1), MAX\_PATH);
m\_csOriginalSDateFormat.ReleaseBuffer();

(m_csOriginalSDateFormat is a CString) Next have your own CString with the desired format:

m_csNewSDateFormat = _T("M/d/yyyy");

Now, set the desired format, parse the date/time, and restore the original format:

SetLocaleInfo(m_LCID, LOCALE_SSHORTDATE, m_csNewSDateFormat);
oleStartTime.ParseDateTime(csDateTime);
SetLocaleInfo(m_LCID, LOCALE_SSHORTDATE, m_csOriginalSDateFormat);

Hope this helps.

Karl - WK5M PP-ASEL-IA (N43CS) PGP Key: 0xDB02E193 PGP Key Fingerprint: 8F06 5A2E 2735 892B 821C 871A 0411 94EA DB02 E193

Software_Developer

My mistake. Didn't notice that CStrings only compile in MFC.

char buffer[256];
CString cs = buffer;

CString Management[^]

BadJerry

That's clever!

Software_Developer

*FACEPALM* COleDateTime::Format MSDN[^]

COleDateTime t(1999, 3, 19, 22, 15, 0);

CString str = t.Format(_T("%A, %B %d, %Y"));

BadJerry

Thanks again... but this is to return a string with a format... What I wanted is to parse a string into a date with a format! Something like

COleDatetime t;
t.IsThisStringADateWithThisFormat(_T("10012012"),"ddMMyyyy");

But I have managed (see my post above)! Thanks anyway! Jerry

jschell

Richard MacCutchan wrote:

It's strptime() which, unfortunately, is not available in Windows

Very odd. Far as I can tell strptime is not part of ANSI C. Which makes me wonder why.

Lost User

It's POSIX according to the man page[^].

One of these days I'm going to think of a really clever signature.