dcdatetimezone.f90 File Reference

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Functions/Subroutines
subroutine	dcdatetimesetzone (time, zone, err)
	Procedures for timezone handling.
type(dc_difftime) function	dcdatetimezonetodiff (zone)
logical function	dcdatetimevalidzone (zone)

Function/Subroutine Documentation

dcdatetimesetzone()

subroutine dcdatetimesetzone	(	type(dc_datetime), intent(inout)	time,
		character(*), intent(in)	zone,
		logical, intent(out), optional	err )

Procedures for timezone handling.

Author

Yasuhiro MORIKAWA

Copyright

Copyright (C) GFD Dennou Club, 2000-2026. All rights reserved.
License is BSD-2-Clause. see COPYRIGHT in detail

Procedures described in this file are provided from "dc_date" module.

Set the timezone of a datetime

Change the timezone of the argument time to zone. The actual datetime is not changed.

If an invalid value is given to the argument zone, an error is raised. If the argument err is given, .true. is returned to err and the program continues.

Parameters

[in,out]	time	Datetime to change timezone
[in]	zone	Timezone to set (e.g., "+09:00")
[out]	err	Exception handling flag

Definition at line 53 of file dcdatetimezone.f90.

 
  use dc_types,      only: string
  use dc_date_types, only: dc_datetime, dc_difftime
  use dc_date_generic, only: validzone, zonetodiff, tochar, eval, &
    & operator(-), operator(+)
  use dc_error, only: storeerror, dc_ebadtimezone, dc_noerr
  use dc_message, only: messagenotify
  use dc_trace, only: beginsub, endsub
  use dc_string, only: stoi
  implicit none
  type(DC_DATETIME), intent(inout):: time
  character(*), intent(in):: zone
  logical, intent(out), optional:: err
  type(DC_DIFFTIME):: diff, diff_in
  integer :: stat
  character(STRING) :: zone_in, cause_c
  character(*), parameter :: subname = 'DCDateTimeSetZone'
continue
  call beginsub(subname, 'time=%c, zone=%c', &
    & c1=trim(tochar(time)), c2=trim(zone))
  stat = dc_noerr
  cause_c = ''
 
  if (.not. validzone(zone)) then
    stat = dc_ebadtimezone
    cause_c = zone
    if (present(err)) then
      call messagenotify('W', subname, &
        & 'zone=<%c> is invalid.', &
        & c1=trim(zone))
    else
      goto 999
    end if
  end if
 
  call eval(time, zone = zone_in)
  diff_in = zonetodiff(zone_in)
  diff = zonetodiff(zone)
 
  time = time + (diff_in - diff)
  time % zone = zone
 
999 continue
  call storeerror(stat, subname, err, cause_c)
  call endsub(subname, 'time=%c', &
    & c1=trim(tochar(time)))

References dc_trace::beginsub(), dc_error::dc_ebadtimezone, dc_error::dc_noerr, dc_trace::endsub(), dc_error::storeerror(), and dc_types::string.

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dcdatetimevalidzone()

logical function dcdatetimevalidzone

(

character(*), intent(in)

zone

)

Check if timezone notation is valid

Returns .true. if the given timezone notation is valid, .false. otherwise.

The timezone notation should be like '+09:00', where the 1st character is '+' or '-', 2nd-3rd and 5th-6th characters are digits, and 4th character is ':'.

Parameters

[in]

zone

Timezone string to check

Returns

.true. if valid, .false. otherwise

Definition at line 173 of file dcdatetimezone.f90.

 
  implicit none
  character(*), intent(in):: zone
  logical:: result
continue
  result = .false.
  if (len(zone) < 6) return
  if (verify(zone(1:1), '+-') /= 0) return
  if (verify(zone(2:3), '1234567890') /= 0) return
  if (verify(zone(5:6), '1234567890') /= 0) return
  if (zone(4:4) /= ':') return
  result = .true.

dcdatetimezonetodiff()

type(dc_difftime) function dcdatetimezonetodiff

(

character(*), intent(in)

zone

)

Convert timezone string to DC_DIFFTIME

Convert the given timezone to a dc_date_types#DC_DIFFTIME variable and return it. If the timezone notation is invalid, it is interpreted as if '+00:00' was given.

Parameters

[in]

zone

Timezone string (e.g., "+09:00")

Returns

Time difference corresponding to the timezone

Definition at line 123 of file dcdatetimezone.f90.

 
  use dc_date_types, only: dc_difftime
  use dc_date_generic, only: validzone, dcdifftimecreate
  use dc_string, only: stoi
  implicit none
  type(DC_DIFFTIME):: diff
  character(*), intent(in):: zone
  integer:: hour, min, sgn
continue
  if (.not. validzone(zone)) then
    call dcdifftimecreate(diff)
  else
    if (zone(1:1) == '-') then
      sgn = 1
    else
      sgn = -1
    end if
    hour = stoi(zone(2:3))
    min = stoi(zone(5:6))
    call dcdifftimecreate(diff, hour = hour * sgn, min = min * sgn)
  end if