vendor/rails/activesupport/lib/active_support/vendor/tzinfo-0.3.12/tzinfo/timezone_transition_info.rb

   1 #--
   2 # Copyright (c) 2006 Philip Ross
   3 #
   4 # Permission is hereby granted, free of charge, to any person obtaining a copy
   5 # of this software and associated documentation files (the "Software"), to deal
   6 # in the Software without restriction, including without limitation the rights
   7 # to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
   8 # copies of the Software, and to permit persons to whom the Software is
   9 # furnished to do so, subject to the following conditions:
  10 #
  11 # The above copyright notice and this permission notice shall be included in all
  12 # copies or substantial portions of the Software.
  13 #
  14 # THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  15 # IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  16 # FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
  17 # AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  18 # LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
  19 # OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
  20 # THE SOFTWARE.
  21 #++
  22
  23 require 'date'
  24 require 'tzinfo/time_or_datetime'
  25
  26 module TZInfo
  27   # Represents an offset defined in a Timezone data file.
  28   class TimezoneTransitionInfo #:nodoc:
  29     # The offset this transition changes to (a TimezoneOffsetInfo instance).
  30     attr_reader :offset
  31
  32     # The offset this transition changes from (a TimezoneOffsetInfo instance).
  33     attr_reader :previous_offset
  34
  35     # The numerator of the DateTime if the transition time is defined as a
  36     # DateTime, otherwise the transition time as a timestamp.
  37     attr_reader :numerator_or_time
  38     protected :numerator_or_time
  39
  40     # Either the denominotor of the DateTime if the transition time is defined
  41     # as a DateTime, otherwise nil.
  42     attr_reader :denominator
  43     protected :denominator
  44
  45     # Creates a new TimezoneTransitionInfo with the given offset,
  46     # previous_offset (both TimezoneOffsetInfo instances) and UTC time.
  47     # if denominator is nil, numerator_or_time is treated as a number of
  48     # seconds since the epoch. If denominator is specified numerator_or_time
  49     # and denominator are used to create a DateTime as follows:
  50     #
  51     #  DateTime.new!(Rational.send(:new!, numerator_or_time, denominator), 0, Date::ITALY)
  52     #
  53     # For performance reasons, the numerator and denominator must be specified
  54     # in their lowest form.
  55     def initialize(offset, previous_offset, numerator_or_time, denominator = nil)
  56       @offset = offset
  57       @previous_offset = previous_offset
  58       @numerator_or_time = numerator_or_time
  59       @denominator = denominator
  60
  61       @at = nil
  62       @local_end = nil
  63       @local_start = nil
  64     end
  65
  66     # A TimeOrDateTime instance representing the UTC time when this transition
  67     # occurs.
  68     def at
  69       unless @at
  70         unless @denominator
  71           @at = TimeOrDateTime.new(@numerator_or_time)
  72         else
  73           r = RubyCoreSupport.rational_new!(@numerator_or_time, @denominator)
  74           dt = RubyCoreSupport.datetime_new!(r, 0, Date::ITALY)
  75           @at = TimeOrDateTime.new(dt)
  76         end
  77       end
  78
  79       @at
  80     end
  81
  82     # A TimeOrDateTime instance representing the local time when this transition
  83     # causes the previous observance to end (calculated from at using
  84     # previous_offset).
  85     def local_end
  86       @local_end = at.add_with_convert(@previous_offset.utc_total_offset) unless @local_end
  87       @local_end
  88     end
  89
  90     # A TimeOrDateTime instance representing the local time when this transition
  91     # causes the next observance to start (calculated from at using offset).
  92     def local_start
  93       @local_start = at.add_with_convert(@offset.utc_total_offset) unless @local_start
  94       @local_start
  95     end
  96
  97     # Returns true if this TimezoneTransitionInfo is equal to the given
  98     # TimezoneTransitionInfo. Two TimezoneTransitionInfo instances are
  99     # considered to be equal by == if offset, previous_offset and at are all
 100     # equal.
 101     def ==(tti)
 102       tti.respond_to?(:offset) && tti.respond_to?(:previous_offset) && tti.respond_to?(:at) &&
 103         offset == tti.offset && previous_offset == tti.previous_offset && at == tti.at
 104     end
 105
 106     # Returns true if this TimezoneTransitionInfo is equal to the given
 107     # TimezoneTransitionInfo. Two TimezoneTransitionInfo instances are
 108     # considered to be equal by eql? if offset, previous_offset,
 109     # numerator_or_time and denominator are all equal. This is stronger than ==,
 110     # which just requires the at times to be equal regardless of how they were
 111     # originally specified.
 112     def eql?(tti)
 113       tti.respond_to?(:offset) && tti.respond_to?(:previous_offset) &&
 114         tti.respond_to?(:numerator_or_time) && tti.respond_to?(:denominator) &&
 115         offset == tti.offset && previous_offset == tti.previous_offset &&
 116         numerator_or_time == tti.numerator_or_time && denominator == tti.denominator
 117     end
 118
 119     # Returns a hash of this TimezoneTransitionInfo instance.
 120     def hash
 121       @offset.hash ^ @previous_offset.hash ^ @numerator_or_time.hash ^ @denominator.hash
 122     end
 123
 124     # Returns internal object state as a programmer-readable string.
 125     def inspect
 126       "#<#{self.class}: #{at.inspect},#{@offset.inspect}>"
 127     end
 128   end
 129 end