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windows-nt/Source/XPSP1/NT/base/fs/fastfat/timesup.c

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2020-09-26 03:20:57 -05:00
/*++
Copyright (c) 1989-2000 Microsoft Corporation
Module Name:
TimeSup.c
Abstract:
This module implements the Fat Time conversion support routines
// @@BEGIN_DDKSPLIT
Author:
Gary Kimura [GaryKi] 19-Feb-1990
Revision History:
// @@END_DDKSPLIT
--*/
#include "FatProcs.h"
#ifdef ALLOC_PRAGMA
#pragma alloc_text(PAGE, FatNtTimeToFatTime)
#pragma alloc_text(PAGE, FatFatDateToNtTime)
#pragma alloc_text(PAGE, FatFatTimeToNtTime)
#pragma alloc_text(PAGE, FatGetCurrentFatTime)
#endif
BOOLEAN
FatNtTimeToFatTime (
IN PIRP_CONTEXT IrpContext,
IN PLARGE_INTEGER NtTime,
IN BOOLEAN Rounding,
OUT PFAT_TIME_STAMP FatTime,
OUT OPTIONAL PCHAR TenMsecs
)
/*++
Routine Description:
This routine converts an NtTime value to its corresponding Fat time value.
Arguments:
NtTime - Supplies the Nt GMT Time value to convert from
Rounding - Indicates whether the NT time should be rounded up to a FAT boundary.
This should only be done *once* in the lifetime of a timestamp (important
for tunneling, which will cause a timestamp to pass through at least twice).
If true, rounded up. If false, rounded down to 10ms boundary. This obeys
the rules for non-creation time and creation times (respectively).
FatTime - Receives the equivalent Fat time value
TenMsecs - Optionally receive the number of tens of milliseconds the NtTime, after
any rounding, is greater than the FatTime
Return Value:
BOOLEAN - TRUE if the Nt time value is within the range of Fat's
time range, and FALSE otherwise
--*/
{
TIME_FIELDS TimeFields;
//
// Convert the input to the a time field record.
//
if (Rounding) {
//
// Add almost two seconds to round up to the nearest double second.
//
NtTime->QuadPart = NtTime->QuadPart + AlmostTwoSeconds;
}
ExSystemTimeToLocalTime( NtTime, NtTime );
RtlTimeToTimeFields( NtTime, &TimeFields );
//
// Check the range of the date found in the time field record
//
if ((TimeFields.Year < 1980) || (TimeFields.Year > (1980 + 127))) {
ExLocalTimeToSystemTime( NtTime, NtTime );
return FALSE;
}
//
// The year will fit in Fat so simply copy over the information
//
FatTime->Time.DoubleSeconds = (USHORT)(TimeFields.Second / 2);
FatTime->Time.Minute = (USHORT)(TimeFields.Minute);
FatTime->Time.Hour = (USHORT)(TimeFields.Hour);
FatTime->Date.Year = (USHORT)(TimeFields.Year - 1980);
FatTime->Date.Month = (USHORT)(TimeFields.Month);
FatTime->Date.Day = (USHORT)(TimeFields.Day);
if (TenMsecs) {
if (!Rounding) {
//
// If the number of seconds was not divisible by two, then there
// is another second of time (1 sec, 3 sec, etc.) Note we round down
// the number of milleconds onto tens of milleseconds boundaries.
//
*TenMsecs = (TimeFields.Milliseconds / 10) +
((TimeFields.Second % 2) * 100);
} else {
//
// If we rounded up, we have in effect changed the NT time. Therefore,
// it does not differ from the FAT time.
//
*TenMsecs = 0;
}
}
if (Rounding) {
//
// Slice off non-FAT boundary time and convert back to 64bit form
//
TimeFields.Milliseconds = 0;
TimeFields.Second -= TimeFields.Second % 2;
} else {
//
// Round down to 10ms boundary
//
TimeFields.Milliseconds -= TimeFields.Milliseconds % 10;
}
//
// Convert back to NT time
//
(VOID) RtlTimeFieldsToTime(&TimeFields, NtTime);
ExLocalTimeToSystemTime( NtTime, NtTime );
UNREFERENCED_PARAMETER( IrpContext );
return TRUE;
}
LARGE_INTEGER
FatFatDateToNtTime (
IN PIRP_CONTEXT IrpContext,
IN FAT_DATE FatDate
)
/*++
Routine Description:
This routine converts a Fat datev value to its corresponding Nt GMT
Time value.
Arguments:
FatDate - Supplies the Fat Date to convert from
Return Value:
LARGE_INTEGER - Receives the corresponding Nt Time value
--*/
{
TIME_FIELDS TimeFields;
LARGE_INTEGER Time;
//
// Pack the input time/date into a time field record
//
TimeFields.Year = (USHORT)(FatDate.Year + 1980);
TimeFields.Month = (USHORT)(FatDate.Month);
TimeFields.Day = (USHORT)(FatDate.Day);
TimeFields.Hour = (USHORT)0;
TimeFields.Minute = (USHORT)0;
TimeFields.Second = (USHORT)0;
TimeFields.Milliseconds = (USHORT)0;
//
// Convert the time field record to Nt LARGE_INTEGER, and set it to zero
// if we were given a bogus time.
//
if (!RtlTimeFieldsToTime( &TimeFields, &Time )) {
Time.LowPart = 0;
Time.HighPart = 0;
} else {
ExLocalTimeToSystemTime( &Time, &Time );
}
return Time;
UNREFERENCED_PARAMETER( IrpContext );
}
LARGE_INTEGER
FatFatTimeToNtTime (
IN PIRP_CONTEXT IrpContext,
IN FAT_TIME_STAMP FatTime,
IN UCHAR TenMilliSeconds
)
/*++
Routine Description:
This routine converts a Fat time value pair to its corresponding Nt GMT
Time value.
Arguments:
FatTime - Supplies the Fat Time to convert from
TenMilliSeconds - A 10 Milisecond resolution
Return Value:
LARGE_INTEGER - Receives the corresponding Nt GMT Time value
--*/
{
TIME_FIELDS TimeFields;
LARGE_INTEGER Time;
//
// Pack the input time/date into a time field record
//
TimeFields.Year = (USHORT)(FatTime.Date.Year + 1980);
TimeFields.Month = (USHORT)(FatTime.Date.Month);
TimeFields.Day = (USHORT)(FatTime.Date.Day);
TimeFields.Hour = (USHORT)(FatTime.Time.Hour);
TimeFields.Minute = (USHORT)(FatTime.Time.Minute);
TimeFields.Second = (USHORT)(FatTime.Time.DoubleSeconds * 2);
if (TenMilliSeconds != 0) {
TimeFields.Second += (USHORT)(TenMilliSeconds / 100);
TimeFields.Milliseconds = (USHORT)((TenMilliSeconds % 100) * 10);
} else {
TimeFields.Milliseconds = (USHORT)0;
}
//
// If the second value is greater than 59 then we truncate it to 0.
// Note that this can't happen with a proper FAT timestamp.
//
if (TimeFields.Second > 59) {
TimeFields.Second = 0;
}
//
// Convert the time field record to Nt LARGE_INTEGER, and set it to zero
// if we were given a bogus time.
//
if (!RtlTimeFieldsToTime( &TimeFields, &Time )) {
Time.LowPart = 0;
Time.HighPart = 0;
} else {
ExLocalTimeToSystemTime( &Time, &Time );
}
return Time;
UNREFERENCED_PARAMETER( IrpContext );
}
FAT_TIME_STAMP
FatGetCurrentFatTime (
IN PIRP_CONTEXT IrpContext
)
/*++
Routine Description:
This routine returns the current system time in Fat time
Arguments:
Return Value:
FAT_TIME_STAMP - Receives the current system time
--*/
{
LARGE_INTEGER Time;
TIME_FIELDS TimeFields;
FAT_TIME_STAMP FatTime;
//
// Get the current system time, and map it into a time field record.
//
KeQuerySystemTime( &Time );
ExSystemTimeToLocalTime( &Time, &Time );
//
// Always add almost two seconds to round up to the nearest double second.
//
Time.QuadPart = Time.QuadPart + AlmostTwoSeconds;
(VOID)RtlTimeToTimeFields( &Time, &TimeFields );
//
// Now simply copy over the information
//
FatTime.Time.DoubleSeconds = (USHORT)(TimeFields.Second / 2);
FatTime.Time.Minute = (USHORT)(TimeFields.Minute);
FatTime.Time.Hour = (USHORT)(TimeFields.Hour);
FatTime.Date.Year = (USHORT)(TimeFields.Year - 1980);
FatTime.Date.Month = (USHORT)(TimeFields.Month);
FatTime.Date.Day = (USHORT)(TimeFields.Day);
UNREFERENCED_PARAMETER( IrpContext );
return FatTime;
}
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