vendor/rails/activesupport/lib/active_support/vendor/tzinfo-0.3.12/tzinfo/timezone_offset_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 module TZInfo
  24   # Represents an offset defined in a Timezone data file.
  25   class TimezoneOffsetInfo #:nodoc:
  26     # The base offset of the timezone from UTC in seconds.
  27     attr_reader :utc_offset
  28
  29     # The offset from standard time for the zone in seconds (i.e. non-zero if
  30     # daylight savings is being observed).
  31     attr_reader :std_offset
  32
  33     # The total offset of this observance from UTC in seconds
  34     # (utc_offset + std_offset).
  35     attr_reader :utc_total_offset
  36
  37     # The abbreviation that identifies this observance, e.g. "GMT"
  38     # (Greenwich Mean Time) or "BST" (British Summer Time) for "Europe/London". The returned identifier is a
  39     # symbol.
  40     attr_reader :abbreviation
  41
  42     # Constructs a new TimezoneOffsetInfo. utc_offset and std_offset are
  43     # specified in seconds.
  44     def initialize(utc_offset, std_offset, abbreviation)
  45       @utc_offset = utc_offset
  46       @std_offset = std_offset
  47       @abbreviation = abbreviation
  48
  49       @utc_total_offset = @utc_offset + @std_offset
  50     end
  51
  52     # True if std_offset is non-zero.
  53     def dst?
  54       @std_offset != 0
  55     end
  56
  57     # Converts a UTC DateTime to local time based on the offset of this period.
  58     def to_local(utc)
  59       TimeOrDateTime.wrap(utc) {|wrapped|
  60         wrapped + @utc_total_offset
  61       }
  62     end
  63
  64     # Converts a local DateTime to UTC based on the offset of this period.
  65     def to_utc(local)
  66       TimeOrDateTime.wrap(local) {|wrapped|
  67         wrapped - @utc_total_offset
  68       }
  69     end
  70
  71     # Returns true if and only if toi has the same utc_offset, std_offset
  72     # and abbreviation as this TimezoneOffsetInfo.
  73     def ==(toi)
  74       toi.respond_to?(:utc_offset) && toi.respond_to?(:std_offset) && toi.respond_to?(:abbreviation) &&
  75         utc_offset == toi.utc_offset && std_offset == toi.std_offset && abbreviation == toi.abbreviation
  76     end
  77
  78     # Returns true if and only if toi has the same utc_offset, std_offset
  79     # and abbreviation as this TimezoneOffsetInfo.
  80     def eql?(toi)
  81       self == toi
  82     end
  83
  84     # Returns a hash of this TimezoneOffsetInfo.
  85     def hash
  86       utc_offset.hash ^ std_offset.hash ^ abbreviation.hash
  87     end
  88
  89     # Returns internal object state as a programmer-readable string.
  90     def inspect
  91       "#<#{self.class}: #@utc_offset,#@std_offset,#@abbreviation>"
  92     end
  93   end
  94 end