Windows-Server-2003/inetcore/urlmon/utils/coletime.cxx

863 lines
23 KiB
C++

#include <urlint.h>
#include <map_kv.h>
#include "coll.hxx"
#include "coletime.hxx"
#include <math.h>
/////////////////////////////////////////////////////////////////////////////
// COleDateTime class HELPER definitions
// Verifies will fail if the needed buffer size is too large
#define MAX_TIME_BUFFER_SIZE 128 // matches that in timecore.cpp
#define MIN_DATE (-657434L) // about year 100
#define MAX_DATE 2958465L // about year 9999
// Half a second, expressed in days
#define HALF_SECOND (1.0/172800.0)
// One-based array of days in year at month start
static int rgMonthDays[13] =
{0, 31, 59, 90, 120, 151, 181, 212, 243, 273, 304, 334, 365};
static BOOL OleDateFromTm(WORD wYear, WORD wMonth, WORD wDay,
WORD wHour, WORD wMinute, WORD wSecond, DATE& dtDest);
static BOOL TmFromOleDate(DATE dtSrc, struct tm& tmDest);
static void TmConvertToStandardFormat(struct tm& tmSrc);
static double DoubleFromDate(DATE dt);
static DATE DateFromDouble(double dbl);
/////////////////////////////////////////////////////////////////////////////
// COleDateTime class
COleDateTime PASCAL COleDateTime::GetCurrentTime()
{
return COleDateTime(::time(NULL));
}
int COleDateTime::GetYear() const
{
struct tm tmTemp;
if (GetStatus() == valid && TmFromOleDate(m_dt, tmTemp))
return tmTemp.tm_year;
else
return AFX_OLE_DATETIME_ERROR;
}
int COleDateTime::GetMonth() const
{
struct tm tmTemp;
if (GetStatus() == valid && TmFromOleDate(m_dt, tmTemp))
return tmTemp.tm_mon;
else
return AFX_OLE_DATETIME_ERROR;
}
int COleDateTime::GetDay() const
{
struct tm tmTemp;
if (GetStatus() == valid && TmFromOleDate(m_dt, tmTemp))
return tmTemp.tm_mday;
else
return AFX_OLE_DATETIME_ERROR;
}
int COleDateTime::GetHour() const
{
struct tm tmTemp;
if (GetStatus() == valid && TmFromOleDate(m_dt, tmTemp))
return tmTemp.tm_hour;
else
return AFX_OLE_DATETIME_ERROR;
}
int COleDateTime::GetMinute() const
{
struct tm tmTemp;
if (GetStatus() == valid && TmFromOleDate(m_dt, tmTemp))
return tmTemp.tm_min;
else
return AFX_OLE_DATETIME_ERROR;
}
int COleDateTime::GetSecond() const
{
struct tm tmTemp;
if (GetStatus() == valid && TmFromOleDate(m_dt, tmTemp))
return tmTemp.tm_sec;
else
return AFX_OLE_DATETIME_ERROR;
}
int COleDateTime::GetDayOfWeek() const
{
struct tm tmTemp;
if (GetStatus() == valid && TmFromOleDate(m_dt, tmTemp))
return tmTemp.tm_wday;
else
return AFX_OLE_DATETIME_ERROR;
}
int COleDateTime::GetDayOfYear() const
{
struct tm tmTemp;
if (GetStatus() == valid && TmFromOleDate(m_dt, tmTemp))
return tmTemp.tm_yday;
else
return AFX_OLE_DATETIME_ERROR;
}
#ifdef _not_this_
const COleDateTime& COleDateTime::operator=(const VARIANT& varSrc)
{
if (varSrc.vt != VT_DATE)
{
TRY
{
COleVariant varTemp(varSrc);
varTemp.ChangeType(VT_DATE);
m_dt = varTemp.date;
SetStatus(valid);
}
// Catch COleException from ChangeType, but not CMemoryException
CATCH(COleException, e)
{
// Not able to convert VARIANT to DATE
DELETE_EXCEPTION(e);
m_dt = 0;
SetStatus(invalid);
}
END_CATCH
}
else
{
m_dt = varSrc.date;
SetStatus(valid);
}
return *this;
}
#endif //_not_this_
const COleDateTime& COleDateTime::operator=(DATE dtSrc)
{
m_dt = dtSrc;
SetStatus(valid);
return *this;
}
const COleDateTime& COleDateTime::operator=(const time_t& timeSrc)
{
// Convert time_t to struct tm
tm *ptm = localtime(&timeSrc);
if (ptm != NULL)
{
m_status = OleDateFromTm((WORD)ptm->tm_year + 1900,
(WORD)(ptm->tm_mon + 1), (WORD)ptm->tm_mday,
(WORD)ptm->tm_hour, (WORD)ptm->tm_min,
(WORD)ptm->tm_sec, m_dt) ? valid : invalid;
}
else
{
// Local time must have failed (timsSrc before 1/1/70 12am)
SetStatus(invalid);
ASSERT(FALSE);
}
return *this;
}
const COleDateTime& COleDateTime::operator=(const SYSTEMTIME& systimeSrc)
{
m_status = OleDateFromTm(systimeSrc.wYear, systimeSrc.wMonth,
systimeSrc.wDay, systimeSrc.wHour, systimeSrc.wMinute,
systimeSrc.wSecond, m_dt) ? valid : invalid;
return *this;
}
const COleDateTime& COleDateTime::operator=(const FILETIME& filetimeSrc)
{
// Assume UTC FILETIME, so convert to LOCALTIME
FILETIME filetimeLocal;
if (!FileTimeToLocalFileTime( &filetimeSrc, &filetimeLocal))
{
#ifdef _DEBUG
DWORD dwError = GetLastError();
TRACE1("\nFileTimeToLocalFileTime failed. Error = %lu.\n\t", dwError);
#endif // _DEBUG
m_status = invalid;
}
else
{
// Take advantage of SYSTEMTIME -> FILETIME conversion
SYSTEMTIME systime;
m_status = FileTimeToSystemTime(&filetimeLocal, &systime) ?
valid : invalid;
// At this point systime should always be valid, but...
if (GetStatus() == valid)
{
m_status = OleDateFromTm(systime.wYear, systime.wMonth,
systime.wDay, systime.wHour, systime.wMinute,
systime.wSecond, m_dt) ? valid : invalid;
}
}
return *this;
}
BOOL COleDateTime::operator<(const COleDateTime& date) const
{
ASSERT(GetStatus() == valid);
ASSERT(date.GetStatus() == valid);
// Handle negative dates
return DoubleFromDate(m_dt) < DoubleFromDate(date.m_dt);
}
BOOL COleDateTime::operator>(const COleDateTime& date) const
{ ASSERT(GetStatus() == valid);
ASSERT(date.GetStatus() == valid);
// Handle negative dates
return DoubleFromDate(m_dt) > DoubleFromDate(date.m_dt);
}
BOOL COleDateTime::operator<=(const COleDateTime& date) const
{
ASSERT(GetStatus() == valid);
ASSERT(date.GetStatus() == valid);
// Handle negative dates
return DoubleFromDate(m_dt) <= DoubleFromDate(date.m_dt);
}
BOOL COleDateTime::operator>=(const COleDateTime& date) const
{
ASSERT(GetStatus() == valid);
ASSERT(date.GetStatus() == valid);
// Handle negative dates
return DoubleFromDate(m_dt) >= DoubleFromDate(date.m_dt);
}
COleDateTime COleDateTime::operator+(const COleDateTimeSpan& dateSpan) const
{
COleDateTime dateResult; // Initializes m_status to valid
// If either operand NULL, result NULL
if (GetStatus() == null || dateSpan.GetStatus() == null)
{
dateResult.SetStatus(null);
return dateResult;
}
// If either operand invalid, result invalid
if (GetStatus() == invalid || dateSpan.GetStatus() == invalid)
{
dateResult.SetStatus(invalid);
return dateResult;
}
// Compute the actual date difference by adding underlying dates
dateResult = DateFromDouble(DoubleFromDate(m_dt) + dateSpan.m_span);
// Validate within range
dateResult.CheckRange();
return dateResult;
}
COleDateTime COleDateTime::operator-(const COleDateTimeSpan& dateSpan) const
{
COleDateTime dateResult; // Initializes m_status to valid
// If either operand NULL, result NULL
if (GetStatus() == null || dateSpan.GetStatus() == null)
{
dateResult.SetStatus(null);
return dateResult;
}
// If either operand invalid, result invalid
if (GetStatus() == invalid || dateSpan.GetStatus() == invalid)
{
dateResult.SetStatus(invalid);
return dateResult;
}
// Compute the actual date difference by subtracting underlying dates
dateResult = DateFromDouble(DoubleFromDate(m_dt) - dateSpan.m_span);
// Validate within range
dateResult.CheckRange();
return dateResult;
}
COleDateTimeSpan COleDateTime::operator-(const COleDateTime& date) const
{
COleDateTimeSpan spanResult;
// If either operand NULL, result NULL
if (GetStatus() == null || date.GetStatus() == null)
{
spanResult.SetStatus(COleDateTimeSpan::null);
return spanResult;
}
// If either operand invalid, result invalid
if (GetStatus() == invalid || date.GetStatus() == invalid)
{
spanResult.SetStatus(COleDateTimeSpan::invalid);
return spanResult;
}
// Return result (span can't be invalid, so don't check range)
return DoubleFromDate(m_dt) - DoubleFromDate(date.m_dt);
}
BOOL COleDateTime::SetDateTime(int nYear, int nMonth, int nDay,
int nHour, int nMin, int nSec)
{
return m_status = OleDateFromTm((WORD)nYear, (WORD)nMonth,
(WORD)nDay, (WORD)nHour, (WORD)nMin, (WORD)nSec, m_dt) ?
valid : invalid;
}
#ifdef _not_yet_
BOOL COleDateTime::ParseDateTime(LPCTSTR lpszDate, DWORD dwFlags, LCID lcid)
{
USES_CONVERSION;
CString strDate = lpszDate;
SCODE sc;
if (FAILED(sc = VarDateFromStr((LPOLESTR)T2COLE(strDate), lcid,
dwFlags, &m_dt)))
{
if (sc == DISP_E_TYPEMISMATCH)
{
// Can't convert string to date, set 0 and invalidate
m_dt = 0;
SetStatus(invalid);
return FALSE;
}
else if (sc == DISP_E_OVERFLOW)
{
// Can't convert string to date, set -1 and invalidate
m_dt = -1;
SetStatus(invalid);
return FALSE;
}
else
{
TRACE0("\nCOleDateTime VarDateFromStr call failed.\n\t");
if (sc == E_OUTOFMEMORY)
AfxThrowMemoryException();
else
AfxThrowOleException(sc);
}
}
SetStatus(valid);
return TRUE;
}
CString COleDateTime::Format(DWORD dwFlags, LCID lcid) const
{
USES_CONVERSION;
CString strDate;
// If null, return empty string
if (GetStatus() == null)
return strDate;
// If invalid, return DateTime resource string
if (GetStatus() == invalid)
{
VERIFY(strDate.LoadString(AFX_IDS_INVALID_DATETIME));
return strDate;
}
COleVariant var;
// Don't need to trap error. Should not fail due to type mismatch
CheckError(VarBstrFromDate(m_dt, lcid, dwFlags, &V_BSTR(&var)));
var.vt = VT_BSTR;
return OLE2CT(V_BSTR(&var));
}
#endif //_not_yet_
CString COleDateTime::Format(LPCTSTR pFormat) const
{
CString strDate;
struct tm tmTemp;
// If null, return empty string
if (GetStatus() == null)
return strDate;
// If invalid, return DateTime resource string
if (GetStatus() == invalid || !TmFromOleDate(m_dt, tmTemp))
{
//VERIFY(strDate.LoadString(AFX_IDS_INVALID_DATETIME));
return strDate;
}
// Convert tm from afx internal format to standard format
TmConvertToStandardFormat(tmTemp);
// Fill in the buffer, disregard return value as it's not necessary
LPTSTR lpszTemp = strDate.GetBufferSetLength(MAX_TIME_BUFFER_SIZE);
_tcsftime(lpszTemp, strDate.GetLength(), pFormat, &tmTemp);
strDate.ReleaseBuffer();
return strDate;
}
CString COleDateTime::Format(UINT nFormatID) const
{
CString strFormat;
//VERIFY(strFormat.LoadString(nFormatID) != 0);
return Format(strFormat);
}
void COleDateTime::CheckRange()
{
if (m_dt > MAX_DATE || m_dt < MIN_DATE) // about year 100 to about 9999
SetStatus(invalid);
}
// serialization
#ifdef _DEBUG
CDumpContext& AFXAPI operator<<(CDumpContext& dc, COleDateTime dateSrc)
{
dc << "\nCOleDateTime Object:";
dc << "\n\tm_status = " << (long)dateSrc.m_status;
COleVariant var(dateSrc);
var.ChangeType(VT_BSTR);
return dc << "\n\tdate = " << (LPCTSTR)var.bstrVal;
}
#endif // _DEBUG
#ifdef _not_yet_
CArchive& AFXAPI operator<<(CArchive& ar, COleDateTime dateSrc)
{
ar << (long)dateSrc.m_status;
return ar << dateSrc.m_dt;
}
CArchive& AFXAPI operator>>(CArchive& ar, COleDateTime& dateSrc)
{
ar >> (long&)dateSrc.m_status;
return ar >> dateSrc.m_dt;
}
#endif //_not_yet_
/////////////////////////////////////////////////////////////////////////////
// COleDateTimeSpan class helpers
#define MAX_DAYS_IN_SPAN 3615897L
/////////////////////////////////////////////////////////////////////////////
// COleDateTimeSpan class
long COleDateTimeSpan::GetHours() const
{
ASSERT(GetStatus() == valid);
double dblTemp;
// Truncate days and scale up
dblTemp = modf(m_span, &dblTemp);
return (long)(dblTemp * 24);
}
long COleDateTimeSpan::GetMinutes() const
{
ASSERT(GetStatus() == valid);
double dblTemp;
// Truncate hours and scale up
dblTemp = modf(m_span * 24, &dblTemp);
return (long)(dblTemp * 60);
}
long COleDateTimeSpan::GetSeconds() const
{
ASSERT(GetStatus() == valid);
double dblTemp;
// Truncate minutes and scale up
dblTemp = modf(m_span * 24 * 60, &dblTemp);
return (long)(dblTemp * 60);
}
const COleDateTimeSpan& COleDateTimeSpan::operator=(double dblSpanSrc)
{
m_span = dblSpanSrc;
SetStatus(valid);
return *this;
}
const COleDateTimeSpan& COleDateTimeSpan::operator=(const COleDateTimeSpan& dateSpanSrc)
{
m_span = dateSpanSrc.m_span;
m_status = dateSpanSrc.m_status;
return *this;
}
COleDateTimeSpan COleDateTimeSpan::operator+(const COleDateTimeSpan& dateSpan) const
{
COleDateTimeSpan dateSpanTemp;
// If either operand Null, result Null
if (GetStatus() == null || dateSpan.GetStatus() == null)
{
dateSpanTemp.SetStatus(null);
return dateSpanTemp;
}
// If either operand Invalid, result Invalid
if (GetStatus() == invalid || dateSpan.GetStatus() == invalid)
{
dateSpanTemp.SetStatus(invalid);
return dateSpanTemp;
}
// Add spans and validate within legal range
dateSpanTemp.m_span = m_span + dateSpan.m_span;
dateSpanTemp.CheckRange();
return dateSpanTemp;
}
COleDateTimeSpan COleDateTimeSpan::operator-(const COleDateTimeSpan& dateSpan) const
{
COleDateTimeSpan dateSpanTemp;
// If either operand Null, result Null
if (GetStatus() == null || dateSpan.GetStatus() == null)
{
dateSpanTemp.SetStatus(null);
return dateSpanTemp;
}
// If either operand Invalid, result Invalid
if (GetStatus() == invalid || dateSpan.GetStatus() == invalid)
{
dateSpanTemp.SetStatus(invalid);
return dateSpanTemp;
}
// Subtract spans and validate within legal range
dateSpanTemp.m_span = m_span - dateSpan.m_span;
dateSpanTemp.CheckRange();
return dateSpanTemp;
}
void COleDateTimeSpan::SetDateTimeSpan(
long lDays, int nHours, int nMins, int nSecs)
{
// Set date span by breaking into fractional days (all input ranges valid)
m_span = lDays + ((double)nHours)/24 + ((double)nMins)/(24*60) +
((double)nSecs)/(24*60*60);
SetStatus(valid);
}
CString COleDateTimeSpan::Format(LPCTSTR pFormat) const
{
CString strSpan;
struct tm tmTemp;
// If null, return empty string
if (GetStatus() == null)
return strSpan;
// If invalid, return DateTimeSpan resource string
if (GetStatus() == invalid || !TmFromOleDate(m_span, tmTemp))
{
//VERIFY(strSpan.LoadString(AFX_IDS_INVALID_DATETIMESPAN));
return strSpan;
}
// Convert tm from afx internal format to standard format
TmConvertToStandardFormat(tmTemp);
// Fill in the buffer, disregard return value as it's not necessary
LPTSTR lpszTemp = strSpan.GetBufferSetLength(MAX_TIME_BUFFER_SIZE);
_tcsftime(lpszTemp, strSpan.GetLength(), pFormat, &tmTemp);
strSpan.ReleaseBuffer();
return strSpan;
}
CString COleDateTimeSpan::Format(UINT nFormatID) const
{
CString strFormat;
//VERIFY(strFormat.LoadString(nFormatID) != 0);
return Format(strFormat);
}
void COleDateTimeSpan::CheckRange()
{
if (m_span < -MAX_DAYS_IN_SPAN || m_span > MAX_DAYS_IN_SPAN)
SetStatus(invalid);
}
// serialization
#ifdef _DEBUG
CDumpContext& AFXAPI operator<<(CDumpContext& dc, COleDateTimeSpan dateSpanSrc)
{
dc << "\nCOleDateTimeSpan Object:";
dc << "\n\tm_status = " << (long)dateSpanSrc.m_status;
COleVariant var(dateSpanSrc.m_span);
var.ChangeType(VT_BSTR);
return dc << "\n\tdateSpan = " << (LPCTSTR)var.bstrVal;
}
#endif // _DEBUG
#ifdef _not_yet_
CArchive& AFXAPI operator<<(CArchive& ar, COleDateTimeSpan dateSpanSrc)
{
ar << (long)dateSpanSrc.m_status;
return ar << dateSpanSrc.m_span;
}
CArchive& AFXAPI operator>>(CArchive& ar, COleDateTimeSpan& dateSpanSrc)
{
ar >> (long&)dateSpanSrc.m_status;
return ar >> dateSpanSrc.m_span;
}
#endif //_not_yet_
/////////////////////////////////////////////////////////////////////////////
// COleDateTime class HELPERS - implementation
BOOL OleDateFromTm(WORD wYear, WORD wMonth, WORD wDay,
WORD wHour, WORD wMinute, WORD wSecond, DATE& dtDest)
{
// Validate year and month (ignore day of week and milliseconds)
if (wYear > 9999 || wMonth < 1 || wMonth > 12)
return FALSE;
// Check for leap year and set the number of days in the month
BOOL bLeapYear = ((wYear & 3) == 0) &&
((wYear % 100) != 0 || (wYear % 400) == 0);
int nDaysInMonth =
rgMonthDays[wMonth] - rgMonthDays[wMonth-1] +
((bLeapYear && wDay == 29 && wMonth == 2) ? 1 : 0);
// Finish validating the date
if (wDay < 1 || wDay > nDaysInMonth ||
wHour > 23 || wMinute > 59 ||
wSecond > 59)
{
return FALSE;
}
// Cache the date in days and time in fractional days
long nDate;
double dblTime;
//It is a valid date; make Jan 1, 1AD be 1
nDate = wYear*365L + wYear/4 - wYear/100 + wYear/400 +
rgMonthDays[wMonth-1] + wDay;
// If leap year and it's before March, subtract 1:
if (wMonth <= 2 && bLeapYear)
--nDate;
// Offset so that 12/30/1899 is 0
nDate -= 693959L;
dblTime = (((long)wHour * 3600L) + // hrs in seconds
((long)wMinute * 60L) + // mins in seconds
((long)wSecond)) / 86400.;
dtDest = (double) nDate + ((nDate >= 0) ? dblTime : -dblTime);
return TRUE;
}
BOOL TmFromOleDate(DATE dtSrc, struct tm& tmDest)
{
// The legal range does not actually span year 0 to 9999.
if (dtSrc > MAX_DATE || dtSrc < MIN_DATE) // about year 100 to about 9999
return FALSE;
long nDays; // Number of days since Dec. 30, 1899
long nDaysAbsolute; // Number of days since 1/1/0
long nSecsInDay; // Time in seconds since midnight
long nMinutesInDay; // Minutes in day
long n400Years; // Number of 400 year increments since 1/1/0
long n400Century; // Century within 400 year block (0,1,2 or 3)
long n4Years; // Number of 4 year increments since 1/1/0
long n4Day; // Day within 4 year block
// (0 is 1/1/yr1, 1460 is 12/31/yr4)
long n4Yr; // Year within 4 year block (0,1,2 or 3)
BOOL bLeap4 = TRUE; // TRUE if 4 year block includes leap year
double dblDate = dtSrc; // tempory serial date
// If a valid date, then this conversion should not overflow
nDays = (long)dblDate;
// Round to the second
dblDate += ((dtSrc > 0.0) ? HALF_SECOND : -HALF_SECOND);
nDaysAbsolute = (long)dblDate + 693959L; // Add days from 1/1/0 to 12/30/1899
dblDate = fabs(dblDate);
nSecsInDay = (long)((dblDate - floor(dblDate)) * 86400.);
// Calculate the day of week (sun=1, mon=2...)
// -1 because 1/1/0 is Sat. +1 because we want 1-based
tmDest.tm_wday = (int)((nDaysAbsolute - 1) % 7L) + 1;
// Leap years every 4 yrs except centuries not multiples of 400.
n400Years = (long)(nDaysAbsolute / 146097L);
// Set nDaysAbsolute to day within 400-year block
nDaysAbsolute %= 146097L;
// -1 because first century has extra day
n400Century = (long)((nDaysAbsolute - 1) / 36524L);
// Non-leap century
if (n400Century != 0)
{
// Set nDaysAbsolute to day within century
nDaysAbsolute = (nDaysAbsolute - 1) % 36524L;
// +1 because 1st 4 year increment has 1460 days
n4Years = (long)((nDaysAbsolute + 1) / 1461L);
if (n4Years != 0)
n4Day = (long)((nDaysAbsolute + 1) % 1461L);
else
{
bLeap4 = FALSE;
n4Day = (long)nDaysAbsolute;
}
}
else
{
// Leap century - not special case!
n4Years = (long)(nDaysAbsolute / 1461L);
n4Day = (long)(nDaysAbsolute % 1461L);
}
if (bLeap4)
{
// -1 because first year has 366 days
n4Yr = (n4Day - 1) / 365;
if (n4Yr != 0)
n4Day = (n4Day - 1) % 365;
}
else
{
n4Yr = n4Day / 365;
n4Day %= 365;
}
// n4Day is now 0-based day of year. Save 1-based day of year, year number
tmDest.tm_yday = (int)n4Day + 1;
tmDest.tm_year = n400Years * 400 + n400Century * 100 + n4Years * 4 + n4Yr;
// Handle leap year: before, on, and after Feb. 29.
if (n4Yr == 0 && bLeap4)
{
// Leap Year
if (n4Day == 59)
{
/* Feb. 29 */
tmDest.tm_mon = 2;
tmDest.tm_mday = 29;
goto DoTime;
}
// Pretend it's not a leap year for month/day comp.
if (n4Day >= 60)
--n4Day;
}
// Make n4DaY a 1-based day of non-leap year and compute
// month/day for everything but Feb. 29.
++n4Day;
// Month number always >= n/32, so save some loop time */
for (tmDest.tm_mon = (n4Day >> 5) + 1;
n4Day > rgMonthDays[tmDest.tm_mon]; tmDest.tm_mon++);
tmDest.tm_mday = (int)(n4Day - rgMonthDays[tmDest.tm_mon-1]);
DoTime:
if (nSecsInDay == 0)
tmDest.tm_hour = tmDest.tm_min = tmDest.tm_sec = 0;
else
{
tmDest.tm_sec = (int)nSecsInDay % 60L;
nMinutesInDay = nSecsInDay / 60L;
tmDest.tm_min = (int)nMinutesInDay % 60;
tmDest.tm_hour = (int)nMinutesInDay / 60;
}
return TRUE;
}
void TmConvertToStandardFormat(struct tm& tmSrc)
{
// Convert afx internal tm to format expected by runtimes (_tcsftime, etc)
tmSrc.tm_year -= 1900; // year is based on 1900
tmSrc.tm_mon -= 1; // month of year is 0-based
tmSrc.tm_wday -= 1; // day of week is 0-based
tmSrc.tm_yday -= 1; // day of year is 0-based
}
double DoubleFromDate(DATE dt)
{
// No problem if positive
if (dt >= 0)
return dt;
// If negative, must convert since negative dates not continuous
// (examples: -1.25 to -.75, -1.50 to -.50, -1.75 to -.25)
double temp = ceil(dt);
return temp - (dt - temp);
}
DATE DateFromDouble(double dbl)
{
// No problem if positive
if (dbl >= 0)
return dbl;
// If negative, must convert since negative dates not continuous
// (examples: -.75 to -1.25, -.50 to -1.50, -.25 to -1.75)
double temp = floor(dbl); // dbl is now whole part
return temp + (temp - dbl);
}