Class: TZInfo::TimezonePeriod

Inherits:
Object
  • Object
show all
Defined in:
lib/tzinfo/timezone_period.rb

Overview

A period of time in a timezone where the same offset from UTC applies.

Constant Summary collapse

@@rational_cache =

A cache of pre-reduced Rationals for each half-hour between -12 and +12. This is used to save time when loading a TimezonePeriod.

{
-43200 => Rational.new!(-1,2),
-41400 => Rational.new!(-23,48),
-39600 => Rational.new!(-11,24),
-37800 => Rational.new!(-7,16),
-36000 => Rational.new!(-5,12),
-34200 => Rational.new!(-19,48),
-32400 => Rational.new!(-3,8),
-30600 => Rational.new!(-17,48),
-28800 => Rational.new!(-1,3),
-27000 => Rational.new!(-5,16),
-25200 => Rational.new!(-7,24),
-23400 => Rational.new!(-13,48),
-21600 => Rational.new!(-1,4),
-19800 => Rational.new!(-11,48),
-18000 => Rational.new!(-5,24),
-16200 => Rational.new!(-3,16),
-14400 => Rational.new!(-1,6),
-12600 => Rational.new!(-7,48),
-10800 => Rational.new!(-1,8),
-9000 =>  Rational.new!(-5,48),
-7200 =>  Rational.new!(-1,12),
-5400 =>  Rational.new!(-1,16),
-3600 =>  Rational.new!(-1,24),
-1800 =>  Rational.new!(-1,48),
0 =>      Rational.new!(0,1),
1800 =>   Rational.new!(1,48),
3600 =>   Rational.new!(1,24),
5400 =>   Rational.new!(1,16),
7200 =>   Rational.new!(1,12),
9000 =>   Rational.new!(5,48),
10800 =>  Rational.new!(1,8),
12600 =>  Rational.new!(7,48),
14400 =>  Rational.new!(1,6),
16200 =>  Rational.new!(3,16),
18000 =>  Rational.new!(5,24),
19800 =>  Rational.new!(11,48),
21600 =>  Rational.new!(1,4),
23400 =>  Rational.new!(13,48),
25200 =>  Rational.new!(7,24),
27000 =>  Rational.new!(5,16),
28800 =>  Rational.new!(1,3),
30600 =>  Rational.new!(17,48),
32400 =>  Rational.new!(3,8),
34200 =>  Rational.new!(19,48),
36000 =>  Rational.new!(5,12),
37800 =>  Rational.new!(7,16),
39600 =>  Rational.new!(11,24),
41400 =>  Rational.new!(23,48),
43200 =>  Rational.new!(1,2)}

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(utc_start, utc_end, utc_offset, std_offset, zone_identifier) ⇒ TimezonePeriod

Initializes a new TimezonePeriod.



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# File 'lib/tzinfo/timezone_period.rb', line 106

def initialize(utc_start, utc_end, utc_offset, std_offset, zone_identifier)
  @utc_start = utc_start
  @utc_end = utc_end
  @utc_offset = utc_offset
  @std_offset = std_offset
  @zone_identifier = zone_identifier
  @utc_total_offset = utc_offset + std_offset
  @utc_total_offset_rational = @@rational_cache[utc_total_offset]
  @utc_total_offset_rational = Rational(utc_total_offset, 86400) if @utc_total_offset_rational.nil?
  
  @local_start = utc_start.nil? ? nil : to_local(utc_start)
  @local_end = utc_end.nil? ? nil : to_local(utc_end)             
end

Instance Attribute Details

#local_end ⇒ Object (readonly)

End time of the period (local time). May be nil if unbounded.



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# File 'lib/tzinfo/timezone_period.rb', line 103

def local_end
  @local_end
end

#local_start ⇒ Object (readonly)

Start time of the period (local time). May be nil if unbounded.



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# File 'lib/tzinfo/timezone_period.rb', line 100

def local_start
  @local_start
end

#std_offset ⇒ Object (readonly)

Offset from the local time where daylight savings is in effect (seconds). E.g.: utc_offset could be -5 hours. Normally, std_offset would be 0. During daylight savings, std_offset would become +1 hours.



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# File 'lib/tzinfo/timezone_period.rb', line 92

def std_offset
  @std_offset
end

#utc_end ⇒ Object (readonly)

End time of the period (UTC). May be nil if unbounded.



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# File 'lib/tzinfo/timezone_period.rb', line 84

def utc_end
  @utc_end
end

#utc_offset ⇒ Object (readonly)

Base offset of the timezone from UTC (seconds).



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# File 'lib/tzinfo/timezone_period.rb', line 87

def utc_offset
  @utc_offset
end

#utc_start ⇒ Object (readonly)

Start time of the period (UTC). May be nil if unbounded.



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# File 'lib/tzinfo/timezone_period.rb', line 81

def utc_start
  @utc_start
end

#zone_identifier ⇒ Object (readonly)

The identifier of this period, e.g. “GMT” (Greenwich Mean Time) or “BST” (British Summer Time) for “Europe/London”. The returned identifier is a symbol.



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# File 'lib/tzinfo/timezone_period.rb', line 97

def zone_identifier
  @zone_identifier
end

Instance Method Details

#dst? ⇒ Boolean

true if daylight savings is in effect for this period; otherwise false.

Returns:

  • (Boolean) 


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# File 'lib/tzinfo/timezone_period.rb', line 131

def dst?
  std_offset != 0
end

#local_after_start?(local) ⇒ Boolean

true if the given local DateTime is after the start of the period (inclusive); otherwise false.

Returns:

  • (Boolean) 


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# File 'lib/tzinfo/timezone_period.rb', line 156

def local_after_start?(local)
  @local_start.nil? || @local_start <= local
end

#local_before_end?(local) ⇒ Boolean

true if the given local DateTime is before the end of the period (exclusive); otherwise false.

Returns:

  • (Boolean) 


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# File 'lib/tzinfo/timezone_period.rb', line 161

def local_before_end?(local)
  @local_end.nil? || @local_end > local
end

#to_local(utc) ⇒ Object

Converts a UTC DateTime to local time based on the offset of this period.



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# File 'lib/tzinfo/timezone_period.rb', line 166

def to_local(utc)
  utc + utc_total_offset_rational
end

#to_utc(local) ⇒ Object

Converts a local DateTime to UTC based on the offset of this period.



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# File 'lib/tzinfo/timezone_period.rb', line 171

def to_utc(local)
  local - utc_total_offset_rational
end

#utc_after_start?(utc) ⇒ Boolean

true if the given utc DateTime is after the start of the period (inclusive); otherwise false.

Returns:

  • (Boolean) 


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# File 'lib/tzinfo/timezone_period.rb', line 141

def utc_after_start?(utc)
  @utc_start.nil? || @utc_start <= utc
end

#utc_before_end?(utc) ⇒ Boolean

true if the given utc DateTime is before the end of the period (exclusive); otherwise false.

Returns:

  • (Boolean) 


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# File 'lib/tzinfo/timezone_period.rb', line 146

def utc_before_end?(utc)
  @utc_end.nil? || @utc_end > utc
end

#utc_total_offset ⇒ Object

Total offset from UTC (seconds). Equal to utc_offset + std_offset.



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# File 'lib/tzinfo/timezone_period.rb', line 121

def utc_total_offset
  @utc_total_offset
end

#utc_total_offset_rational ⇒ Object

Total offset from UTC (days). Result is a Rational.



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# File 'lib/tzinfo/timezone_period.rb', line 126

def utc_total_offset_rational
  @utc_total_offset_rational
end

#valid_for_local?(local) ⇒ Boolean

true if this period is valid for the given local DateTime; otherwise false.

Returns:

  • (Boolean) 


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# File 'lib/tzinfo/timezone_period.rb', line 151

def valid_for_local?(local)
  local_after_start?(local) && local_before_end?(local) 
end

#valid_for_utc?(utc) ⇒ Boolean

true if this period is valid for the given utc DateTime; otherwise false.

Returns:

  • (Boolean) 


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# File 'lib/tzinfo/timezone_period.rb', line 136

def valid_for_utc?(utc)
  utc_after_start?(utc) && utc_before_end?(utc) 
end