Extended Time Format Functions (with Milliseconds)

Environment: Developed with VC6 SP2; Tested under Windows 2000

Extended format a time string with milliseconds. The output string for a time could be 23:59:59.999.

Prototypes

size_t strfstime(char *strDest, 
                 size_t maxsize, 
                 const char *format, 
                 const SYSTEMTIME *stimeptr);

size_t wcsfstime(wchar_t *strDest, 
                 size_t maxsize, 
                 const wchar_t *format, 
                 const SYSTEMTIME *timeptr);

For additional compatibility information, see VC++ documentation for strftime and wcsftime..

Return Value

strfstime returns the number of characters placed in strDest if the total number of resulting characters, including the terminating null, is not more than maxsize. wcsfstime returns the corresponding number of wide characters. Otherwise, the functions return 0, and the contents of strDest is indeterminate.

Parameters

strDest	Output string
maxsize	Maximum length of string
format	Format-control string
stimeptr	SYSTEMTIME data structure

Remarks

The strfstime and wcsfstime functions format the SYSTEMTIME time value in stimeptr according to the supplied format argument and store the result in the buffer strDest. At most, maxsize characters are placed in the string. For a description of the fields in the timeptr structure, see strftime and wcsftime. wcsfstime is the wide-character equivalent of strfstime; its string-pointer argument points to a wide-character string. These functions behave identically otherwise.

Generic-Text Routine Mappings

TCHAR.H Routine

_UNICODE & _MBCS Not Defined
_MBCS Defined
_UNICODE Defined

_tcsfstime strfstime strfstime wcsfstime 

The format argument are the same as documented for VC++ functions strftime and wcsftime. Also one user defined additional format argument is now allowed. This argument is (default):

%s        Milliseconds as decimal number (000 - 999)

extern "C" {
 const char* strfscode( const char* code );

 size_t strfstime(char *strDest, 
                  size_t maxsize, 
                  const char *format, 
                  const SYSTEMTIME *stimeptr );

 const char* wcsfscode( const wchar_t* code );

 size_t wcsfstime(wchar_t *strDest, 
                  size_t maxsize, 
                  const wchar_t *format, 
                  const SYSTEMTIME *stimeptr );
};

// ------------------------------------------
#ifdef _UNICODE
 #define _tcsfstime wcsftime
#else // _MBCS
 #define _tcsfstime strfstime
#endif

static char szFCode[3] = _T("%s");

const char* strfscode( const char* code )
{
 if( code ){
  strncpy( szFCode, code, sizeof(szFCode)-1);
  szFCode[2] = char(0);
 }

 return szFCode;
}

size_t strfstime(char *strDest, size_t maxsize, 
                 const char *format, const SYSTEMTIME *stimeptr )
{
 struct tm tmTime;

 memset(&tmTime, 0, sizeof(tmTime));

 tmTime.tm_sec = stimeptr->wSecond; // seconds after the minute - [0,59]
 tmTime.tm_min = stimeptr->wMinute; // minutes after the hour - [0,59]
 tmTime.tm_hour = stimeptr->wHour;  // hours since midnight - [0,23]
 ASSERT(stimeptr->wDay >= 1 && stimeptr->wDay <= 31);

 tmTime.tm_mday = stimeptr->wDay;  day of the month - [1,31]
 ASSERT(stimeptr->wMonth >= 1 && stimeptr->wMonth <= 12);

 tmTime.tm_mon = stimeptr->wMonth-1; // months since January - [0,11]
 ASSERT(stimeptr->wYear >= 1900);

 tmTime.tm_year = stimeptr->wYear-1900; // years since 1900 
 tmTime.tm_wday = stimeptr->wDayOfWeek; // days since Sunday - [0,6] 

 // tmTime.tm_yday = NOT USED HERE; // days since January 1 - [0,365] 
 // tmTime.tm_isdst = NOT USED HERE; // daylight savings time flag 

 const char* pStrFound = strstr(format, szFCode );

 if( pStrFound ){

  if( maxsize < (strlen(format)+1+3) )
   return 0;

  char* pNewFormat = new char[maxsize+1];

  long lOffset = pStrFound-format;
  strncpy(pNewFormat, format, lOffset);
  pNewFormat[lOffset] = char(0);

  char szMilliSec[4];
  itoa(stimeptr->wMilliseconds, szMilliSec, 10);
  for(int i=strlen(szMilliSec); i<3; i++ )
   strcat(pNewFormat+lOffset, "0"); 

  strcat(pNewFormat+lOffset, szMilliSec);
  strcat(pNewFormat+lOffset, format+lOffset+strlen(szFCode));

  size_t size = strftime( strDest, maxsize, pNewFormat, &tmTime );

  delete pNewFormat;

  return size;
 }

 return strftime( strDest, maxsize, format, &tmTime );
}

// ------------------------------------------

static wchar_t wszFCode_t[3] = L"%s";

const char* wcsfscode( const wchar_t* code )
{
 if( code ){
  wcsncpy( wszFCode_t, code, sizeof(szFCode)-1);
  wszFCode_t[2] = wchar_t(0);
 }

 return szFCode;
}

size_t wcsfstime(wchar_t *strDest, size_t maxsize, 
                 const wchar_t *format, const SYSTEMTIME *stimeptr )
{
 struct tm tmTime;

 memset(&tmTime, 0, sizeof(tmTime));

 tmTime.tm_sec = stimeptr->wSecond;  seconds after the minute - [0,59] 
 tmTime.tm_min = stimeptr->wMinute; // minutes after the hour - [0,59] 
 tmTime.tm_hour = stimeptr->wHour; // hours since midnight - [0,23] 
 ASSERT(stimeptr->wDay >= 1 && stimeptr->wDay <= 31);

 tmTime.tm_mday = stimeptr->wDay; // day of the month - [1,31] 
 ASSERT(stimeptr->wMonth >= 1 && stimeptr->wMonth <= 12);

 tmTime.tm_mon = stimeptr->wMonth-1; // months since January - [0,11] 
 ASSERT(stimeptr->wYear >= 1900);

 tmTime.tm_year = stimeptr->wYear-1900; // years since 1900 
 tmTime.tm_wday = stimeptr->wDayOfWeek; // days since Sunday - [0,6] 

 // tmTime.tm_yday = NOT USED HERE; // days since January 1 - [0,365] 
 // tmTime.tm_isdst = NOT USED HERE; // daylight savings time flag 

 const wchar_t* pStrFound = wcsstr(format, wszFCode_t );

 if( pStrFound ){
  if( maxsize < (wcslen(format)+1+3) )
   return 0;

  wchar_t* pNewFormat = new wchar_t[maxsize+1];

  long lOffset = pStrFound-format;
  wcsncpy(pNewFormat, format, lOffset);
  pNewFormat[lOffset] = wchar_t(0);

  wchar_t wszMilliSec[4];
  _itow(stimeptr->wMilliseconds, wszMilliSec, 10);
  for(int i=wcslen(wszMilliSec); i<3; i++ )
  wcscat(pNewFormat+lOffset, L"0"); 

  wcscat(pNewFormat+lOffset, wszMilliSec);
  wcscat(pNewFormat+lOffset, format+lOffset+wcslen(wszFCode_t));

  size_t size = wcsftime( strDest, maxsize, pNewFormat, &tmTime );

  delete pNewFormat;

  return size;
 }

 return wcsftime( strDest, maxsize, format, &tmTime );
}

Example

// Create system time structure
SYSTEMTIME SystemTime;
GetSystemTime(&SystemTime);

// Create time string with milliseconds
TCHAR strDest[32];

size_t iSize = strfstime(strDest, 
                         sizeof(strDest), 
                         T("%H:%M:%S.%s"), 
                         &SystemTime );

if( iSize > 0 ){
 // .... do something with the time string
}	

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