Hello,
Is there a function available to convert UTC YYYY/MM/DD MM:SS:SS to local date and time if I pass a parameter such as ET, CT, MT or PT for USA time zones with consideration of DST?
Thank you!
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FiveWin / Harbour / xBase community
Board index FiveWin for Harbour/xHarbour UTC to Local
Cristobal Navarro
Hay dos tipos de personas: las que te hacen perder el tiempo y las que te hacen perder la noción del tiempo
El secreto de la felicidad no está en hacer lo que te gusta, sino en que te guste lo que haces
Hay dos tipos de personas: las que te hacen perder el tiempo y las que te hacen perder la noción del tiempo
El secreto de la felicidad no está en hacer lo que te gusta, sino en que te guste lo que haces
FWH 18.05/xHarbour 1.2.3/BCC7/Windows 10
The question is something like this:
? UTCtoLocalWithDST( STOT( "20150310103000" ), "PT" ) --> 10/03/2015 03:30:00
? UTCtoLocalWithDST( STOT( "20160310103000" ), "PT" ) --> 10/02/2015 02:30:00
For this function to return correct results we need to keep tables of DST for all the zones and years we are interested in.
I do not know if there is any existing database of these dates on internet which can be queried and obtainted. If not, an organisation has to maintain its own tables.
Regards
G. N. Rao.
Hyderabad, India
G. N. Rao.
Hyderabad, India
Dear Rao,
Thank is exactly what I needed. Thank you!
We are going to build a table and add DST for the coming years and add more years as we get them.
We are tracking in real time so we have time to update tables.
Thanks again for your help!
Sincerely,
Dear Rao,
Where can I get details about UTCtoLocalWithDST and STOT?
Thank you,
This simplified program should be enough for your requirements.
#include "fivewin.ch"
static atzones := { ;
{ "ET", -5, -4 }, ; // Eastern
{ "CT", -6, -5 }, ; // Central
{ "MT", -7, -6 }, ; // Mountain
{ "PT", -8, -7 }, ; // Pacific
{ "AT", -9, -8 }, ; // Alaska
{ "HT", -10, -10 }, ; // Hawaii
{ "AR", -7, -7 }, ; // Arizona
{ "SGT", 8, 8 }, ; // Singapore
{ "HKT", 8, 8 } } // Hongkong
static aDsTable := { ;
{ 2015, {^ 2015/03/08 02:00:00 }, {^ 2015/11/01 02:00:00 } }, ;
{ 2016, {^ 2016/03/13 02:00:00 }, {^ 2016/11/06 02:00:00 } }, ;
{ 2017, {^ 2017/03/12 02:00:00 }, {^ 2017/11/05 02:00:00 } }, ;
{ 2018, {^ 2018/03/11 02:00:00 }, {^ 2018/11/04 02:00:00 } }, ;
{ 2019, {^ 2019/03/10 02:00:00 }, {^ 2019/11/03 02:00:00 } } }
//----------------------------------------------------------------------------//
function USATimeTest() // this function is for testing only
local tUTC := DateTime()
local tLocal
SET DATE AMERICAN
SET CENTURY ON
SET TIME FORMAT TO "HH:MM"
// change the test as you like
do while msgget( "USA UTC/Local Conversion", "Enter UTC Date Time", @tUTC )
? tUtc, tLocal := USA_UTCtoLocal( tUtc, "CT" ), USA_LocalToUTC( tLocal, "CT" )
enddo
return nil
//----------------------------------------------------------------------------//
function USA_UTCtoLocal( tUtc, cTimeZone )
local nAt, tLocal
local aInfo := Array( 4 )
DEFAULT cTimeZone := "PT"
cTimeZone := Upper( cTimeZone )
nAt := AScan( aTzones, { |a| a[ 1 ] == cTimeZone } )
if nAt == 0
MsgAlert( "Invalid TimeZone " + cTimeZone )
else
if aTZones[ nAt, 2 ] == aTZones[ nAt, 3 ]
// no daylight savings
tLocal := tUtc + ( aTZones / 24.0 )
else
aInfo[ 1 ] := ATZones[ nAt, 2 ] / 24.0
aInfo[ 2 ] := ATZones[ nAt, 3 ] / 24.0
nAt := AScan( aDsTable, { |a| a[ 1 ] == Year( tUtc ) } )
if nAt == 0
MsgAlert( "Date out of range" )
else
aInfo[ 3 ] := ADsTable[ nAt, 2 ] - aInfo[ 1 ]
aInfo[ 4 ] := ADsTable[ nAt, 3 ] - aInfo[ 2 ]
if tUtc >= aInfo[ 3 ] .and. tUtc <= aInfo[ 4 ]
tLocal := tUtc + aInfo[ 2 ]
else
tLocal := tUtc + aInfo[ 1 ]
endif
endif
endif
endif
return tLocal
//----------------------------------------------------------------------------//
function USA_LocalToUTC( tLocal, cTimeZone )
local nAt, tUtc
local aInfo := Array( 4 )
DEFAULT cTimeZone := "PT"
cTimeZone := Upper( cTimeZone )
nAt := AScan( aTzones, { |a| a[ 1 ] == cTimeZone } )
if nAt == 0
MsgAlert( "Invalid TimeZone " + cTimeZone )
else
if aTZones[ nAt, 2 ] == aTZones[ nAt, 3 ]
// no daylight savings
tUTc := tLocal - ( aTZones / 24.0 )
else
aInfo[ 1 ] := ATZones[ nAt, 2 ] / 24.0
aInfo[ 2 ] := ATZones[ nAt, 3 ] / 24.0
nAt := AScan( aDsTable, { |a| a[ 1 ] == Year( tLocal ) } )
if nAt == 0
MsgAlert( "Date out of range" )
else
aInfo[ 3 ] := ADsTable[ nAt, 2 ]
aInfo[ 4 ] := ADsTable[ nAt, 3 ]
if tLocal >= aInfo[ 3 ] .and. tLocal <= aInfo[ 4 ]
tUTC := tLocal - aInfo[ 2 ]
else
tUTC := tLocal - aInfo[ 1 ]
endif
endif
endif
endif
return tUTC
//----------------------------------------------------------------------------//Regards
G. N. Rao.
Hyderabad, India
G. N. Rao.
Hyderabad, India
Dear Rao,
Thank you. I will be implementing and testing today.
Dear Rao or Anyone That Can Help,
I see the sample of tUTC := DateTime() which works fine.
However, I am reading date and time from a DBF and assigning values dTxDate and cTxtime.
How do I get the dTxdate and cTxTime in the correct format returned by DateTime(), can I pass parameters to DateTime(), i.e., tUTC := DateTime( dTxDate, cTxTime)?
I appreciate anyone's assistance!
Hi Rao,
I used HB_DateTime to resolve this issue.
Sincerely,
Better we stop using date (valtyle 'D') and time (valtype 'C') separately and start dealing with date and time as DateTime varialbles (valtype 'T').
For getting current datetime value we use DateTime() in xHarbour and HB_DateTime() in Harbour.
We can store and retrieve DateTime values in DBF by creating Field with Type 'T'
Eg: { "START", 'T', 8, 0 } // Spec for creating table
When we have Date (valtype 'D') and Time (valtype 'C') separately and want to combine the two into a single DateTime variable, we can use the function FW_ADDTIME( dDate, cTime ).
Eg:
dDate := CTOD( "10/10/2009" )
cTime := "11:12:15"
tDateTime := FW_ADDTIME( dDate, cTime ) // --> 10/10/2009 11:12:15 (valtype 'T')
Regards
G. N. Rao.
Hyderabad, India
G. N. Rao.
Hyderabad, India
Dear Rao,
When we use year 2009 as per example above we receive error as "Date out of range"
Kindly verify
Regards, Greetings
Try FWH. You will enjoy it's simplicity and power.!
Try FWH. You will enjoy it's simplicity and power.!
bpd2000 wrote:Dear Rao,
When we use year 2009 as per example above we receive error as "Date out of range"
Kindly verify
Yes.
For the sample, I entered table of DST for years from 2015 to 2019. This table works for USA for these years. If they want for earlier years, they need to enter information for earlier years too.
If you want for other time zones, you need to enter this information for other timezones.
This sample provides the logic to form the basis for individual implementations.
Regards
G. N. Rao.
Hyderabad, India
G. N. Rao.
Hyderabad, India
Thank you for more info
Regards, Greetings
Try FWH. You will enjoy it's simplicity and power.!
Try FWH. You will enjoy it's simplicity and power.!