Leaked source code of windows server 2003
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#include "ctlspriv.h"
#include "scdttime.h"
// BUGBUG? remove references to 1750 and 1752 as they
// are not needed -- the minimal year we allow is 1753
// to avoid such problems. (We don't care about
// pre-revised-Gregorian dates! If you want to develop
// a history application, then you can deal with these problems)
int mpcdymoAccum[13] =
{ 0, 31, 59, 90, 120, 151, 181, 212, 243, 273, 304, 334, 365 };
/*
- LIncrWord
-
* Purpose:
* Increment (or decrement) an integer by a specified amount,
* given the constraints nMic and nMac.
* Returns the amount of carry into the following (or preceding)
* field, or zero if none.
*
* Intended for use with incrementing date/times.
*
* Arguments:
* pn Pointer to integer to be modified.
* nDelta Amount by which to modify *pn; may be positive,
* negative or zero.
* nMic Minimum value for *pn; if decrementing below this,
* a carry is performed.
* nMac Maximum value for *pn; if incrementing above this,
* a carry is performed.
*
* Returns:
* Zero if modification done within constraints, otherwise the
* amount of carry (positive in incrementing, negative if
* decrementing).
*
*/
LONG LIncrWord(WORD *pn, LONG nDelta, int nMic, int nMac)
{
LONG lNew, lIncr;
lIncr = 0;
lNew = *pn + nDelta;
while (lNew >= nMac)
{
lNew -= nMac - nMic;
lIncr++;
}
if (!lIncr)
{
while (lNew < nMic)
{
lNew += nMac - nMic;
lIncr--;
}
}
*pn = (WORD)lNew;
return(lIncr);
}
void IncrSystemTime(SYSTEMTIME *pstSrc, SYSTEMTIME *pstDest, LONG nDelta, LONG flag)
{
int cdyMon;
if (pstSrc != pstDest)
*pstDest = *pstSrc;
switch (flag)
{
case INCRSYS_SECOND:
if (!(nDelta = LIncrWord(&pstDest->wSecond, nDelta, 0, 60)))
break;
case INCRSYS_MINUTE:
if (!(nDelta = LIncrWord(&pstDest->wMinute, nDelta, 0, 60)))
break;
case INCRSYS_HOUR:
if (!(nDelta = LIncrWord(&pstDest->wHour, nDelta, 0, 24)))
break;
case INCRSYS_DAY:
IDTday:
if (nDelta >= 0)
{
cdyMon = GetDaysForMonth(pstDest->wYear, pstDest->wMonth);
while (pstDest->wDay + nDelta > cdyMon)
{
nDelta -= cdyMon + 1 - pstDest->wDay;
pstDest->wDay = 1;
IncrSystemTime(pstDest, pstDest, 1, INCRSYS_MONTH);
cdyMon = GetDaysForMonth(pstDest->wYear, pstDest->wMonth);
}
}
else
{
while (pstDest->wDay <= -nDelta)
{
nDelta += pstDest->wDay;
IncrSystemTime(pstDest, pstDest, -1, INCRSYS_MONTH);
cdyMon = GetDaysForMonth(pstDest->wYear, pstDest->wMonth);
pstDest->wDay = (WORD) cdyMon;
}
}
pstDest->wDay += (WORD)nDelta;
break;
case INCRSYS_MONTH:
if (!(nDelta = LIncrWord(&pstDest->wMonth, nDelta, 1, 13)))
{
cdyMon = GetDaysForMonth(pstDest->wYear, pstDest->wMonth);
if (pstDest->wDay > cdyMon)
pstDest->wDay = (WORD) cdyMon;
break;
}
case INCRSYS_YEAR:
pstDest->wYear += (WORD)nDelta;
cdyMon = GetDaysForMonth(pstDest->wYear, pstDest->wMonth);
if (pstDest->wDay > cdyMon)
pstDest->wDay = (WORD) cdyMon;
break;
case INCRSYS_WEEK:
nDelta *= 7;
goto IDTday;
break;
}
}
CmpDate(const SYSTEMTIME *pst1, const SYSTEMTIME *pst2)
{
int iRet;
if (pst1->wYear < pst2->wYear)
iRet = -1;
else if (pst1->wYear > pst2->wYear)
iRet = 1;
else if (pst1->wMonth < pst2->wMonth)
iRet = -1;
else if (pst1->wMonth > pst2->wMonth)
iRet = 1;
else if (pst1->wDay < pst2->wDay)
iRet = -1;
else if (pst1->wDay > pst2->wDay)
iRet = 1;
else
iRet = 0;
return(iRet);
}
CmpSystemtime(const SYSTEMTIME *pst1, const SYSTEMTIME *pst2)
{
int iRet;
if (pst1->wYear < pst2->wYear)
iRet = -1;
else if (pst1->wYear > pst2->wYear)
iRet = 1;
else if (pst1->wMonth < pst2->wMonth)
iRet = -1;
else if (pst1->wMonth > pst2->wMonth)
iRet = 1;
else if (pst1->wDay < pst2->wDay)
iRet = -1;
else if (pst1->wDay > pst2->wDay)
iRet = 1;
else if (pst1->wHour < pst2->wHour)
iRet = -1;
else if (pst1->wHour > pst2->wHour)
iRet = 1;
else if (pst1->wMinute < pst2->wMinute)
iRet = -1;
else if (pst1->wMinute > pst2->wMinute)
iRet = 1;
else if (pst1->wSecond < pst2->wSecond)
iRet = -1;
else if (pst1->wSecond > pst2->wSecond)
iRet = 1;
else
iRet = 0;
return(iRet);
}
/*
- CdyBetweenYmd
-
* Purpose:
* Calculate the number of days between two dates as expressed
* in YMD's.
*
* Parameters:
* pymdStart start day of range.
* pymdEnd end day of range.
*
* Returns:
* Number of days between two dates. The number
* of days does not include the starting day, but does include
* the last day. ie 1/24/1990-1/25/1990 = 1 day.
*/
DWORD DaysBetweenDates(const SYSTEMTIME *pstStart, const SYSTEMTIME *pstEnd)
{
DWORD cday;
WORD yr;
// Calculate number of days between the start month/day and the
// end month/day as if they were in the same year - since cday
// is unsigned, cday could be really large if the end month/day
// is before the start month.day.
// This will be cleared up when we account for the days between
// the years.
ASSERT(pstEnd->wMonth >= 1 && pstEnd->wMonth <= 12);
cday = mpcdymoAccum[pstEnd->wMonth - 1] - mpcdymoAccum[pstStart->wMonth - 1] +
pstEnd->wDay - pstStart->wDay;
yr = pstStart->wYear;
// Check to see if the start year is before the end year,
// and if the end month is after February and
// if the end year is a leap year, then add an extra day
// for to account for Feb. 29 in the end year.
if ( ((yr < pstEnd->wYear) || (pstStart->wMonth <= 2)) &&
pstEnd->wMonth > 2 &&
(pstEnd->wYear & 03) == 0 &&
(pstEnd->wYear <= 1750 || pstEnd->wYear % 100 != 0 || pstEnd->wYear % 400 == 0))
{
cday++;
}
// Now account for the leap years in between the start and end dates
// as well as accounting for the days in each year.
if (yr < pstEnd->wYear)
{
// If the start date is before march and the start year is
// a leap year then add an extra day to account for Feb. 29.
if ( pstStart->wMonth <= 2 &&
(yr & 03) == 0 &&
(yr <= 1750 || yr % 100 != 0 || yr % 400 == 0))
{
cday++;
}
// Account for the days in each year (disregarding leap years).
cday += 365;
yr++;
// Keep on accounting for the days in each year including leap
// years until we reach the end year.
while (yr < pstEnd->wYear)
{
cday += 365;
if ((yr & 03) == 0 && (yr <= 1750 || yr % 100 != 0 || yr % 400 == 0))
cday++;
yr++;
}
}
return(cday);
}
/*
- DowStartOfYrMo
-
* Purpose:
* Find the day of the week the indicated month begins on
*
* Parameters:
* yr year, must be > 0
* mo month, number 1-12
*
* Returns:
* day of the week (0-6) on which the month begins
* (0 = Sunday, 1 = Monday etc.)
*/
int GetStartDowForMonth(int yr, int mo)
{
int dow;
// we want monday = 0, sunday = 6
// dow = 6 + (yr - 1) + ((yr - 1) >> 2);
dow = 5 + (yr - 1) + ((yr - 1) >> 2);
if (yr > 1752)
dow += ((yr - 1) - 1600) / 400 - ((yr - 1) - 1700) / 100 - 11;
else if (yr == 1752 && mo > 9)
dow -= 11;
dow += mpcdymoAccum[mo - 1];
if (mo > 2 && (yr & 03) == 0 && (yr <= 1750 || yr % 100 != 0 || yr % 400 == 0))
dow++;
dow %= 7;
return(dow);
}
int DowFromDate(const SYSTEMTIME *pst)
{
int dow;
dow = GetStartDowForMonth(pst->wYear, pst->wMonth);
dow = (dow + pst->wDay - 1) % 7;
return(dow);
}
int GetDaysForMonth(int yr, int mo)
{
int cdy;
if (yr == 1752 && mo == 9)
return(19);
cdy = mpcdymoAccum[mo] - mpcdymoAccum[mo - 1];
if (mo == 2 && (yr & 03) == 0 && (yr <= 1750 || yr % 100 != 0 || yr % 400 == 0))
cdy++;
return(cdy);
}
/*
- NweekNumber
-
* Purpose:
* Calculates week number in which a given date occurs, based
* on a specified start-day of week.
* Adjusts based on how a calendar would show this week
* (ie. week 53 is probably week 1 on the calendar).
*
* Arguments:
* pdtm Pointer to date in question
* dowStartWeek Day-of-week on which weeks starts (0 - 6).
*
* Returns:
* Week number of the year, in which *pdtr occurs.
*
*/
// TODO: this currently ignores woyFirst
// it uses the 1st week containing 4+ days as the first week (woyFirst = 2)
// need to make appropriate changes so it handles woyFirst = 0 and = 1...
int GetWeekNumber(const SYSTEMTIME *pst, int dowFirst, int woyFirst)
{
int day, ddow, ddowT, nweek;
SYSTEMTIME st;
st.wYear = pst->wYear;
st.wMonth = 1;
st.wDay = 1;
ddow = GetStartDowForMonth(st.wYear, st.wMonth) - dowFirst;
if (ddow < 0)
ddow += 7;
if (pst->wMonth == 1 && pst->wDay < 8 - ddow)
{
nweek = 0;
}
else
{
if (ddow)
st.wDay = 8 - ddow;
nweek = (DaysBetweenDates(&st, pst) / 7) + 1;
}
if (ddow && ddow <= 3)
nweek++;
// adjust if necessary for calendar
if (!nweek)
{
if (!ddow)
return(1);
// check what week Dec 31 is on
st.wYear--;
st.wMonth = 12;
st.wDay = 31;
return(GetWeekNumber(&st, dowFirst, woyFirst));
}
else if (nweek >= 52)
{
ddowT = (GetStartDowForMonth(pst->wYear, pst->wMonth) +
pst->wDay - 1 + 7 - dowFirst) % 7;
day = pst->wDay + (7 - ddowT);
if (day > 31 + 4)
nweek = 1;
}
return(nweek);
}
// ignores day of week and time-related fields...
// BUGBUG also validate years in range
BOOL IsValidDate(const SYSTEMTIME *pst)
{
int cDay;
if (pst && pst->wMonth >= 1 && pst->wMonth <= 12)
{
cDay = GetDaysForMonth(pst->wYear, pst->wMonth);
if (pst->wDay >= 1 && pst->wDay <= cDay)
return(TRUE);
}
return(FALSE);
}
// ignores milliseconds and date-related fields...
BOOL IsValidTime(const SYSTEMTIME *pst)
{
return(pst->wHour <= 23 &&
pst->wMinute <= 59 &&
pst->wSecond <= 59);
}
// ignores day of week
BOOL IsValidSystemtime(const SYSTEMTIME *pst)
{
if (pst && pst->wMonth >= 1 && pst->wMonth <= 12)
{
int cDay = GetDaysForMonth(pst->wYear, pst->wMonth);
if (pst->wDay >= 1 &&
pst->wDay <= cDay &&
pst->wHour <= 23 &&
pst->wMinute <= 59 &&
pst->wSecond <= 59 &&
pst->wMilliseconds < 1000)
return(TRUE);
}
return(FALSE);
}