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#--
# Copyright (c) 2006 Philip Ross
#
# Permission is hereby granted, free of charge, to any person obtaining a copy
# of this software and associated documentation files (the "Software"), to deal
# in the Software without restriction, including without limitation the rights
# to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
# copies of the Software, and to permit persons to whom the Software is
# furnished to do so, subject to the following conditions:
#
# The above copyright notice and this permission notice shall be included in all
# copies or substantial portions of the Software.
#
# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
# IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
# FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
# AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
# LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
# OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
# THE SOFTWARE.
#++
require 'tzinfo/time_or_datetime'
require 'tzinfo/timezone_info'
require 'tzinfo/timezone_offset_info'
require 'tzinfo/timezone_period'
require 'tzinfo/timezone_transition_info'
module TZInfo
# Thrown if no offsets have been defined when calling period_for_utc or
# periods_for_local. Indicates an error in the timezone data.
class NoOffsetsDefined < StandardError
end
# Represents a (non-linked) timezone defined in a data module.
class DataTimezoneInfo < TimezoneInfo #:nodoc:
# Constructs a new TimezoneInfo with its identifier.
def initialize(identifier)
super(identifier)
@offsets = {}
@transitions = []
end
# Defines a offset. The id uniquely identifies this offset within the
# timezone. utc_offset and std_offset define the offset in seconds of
# standard time from UTC and daylight savings from standard time
# respectively. abbreviation describes the timezone offset (e.g. GMT, BST,
# EST or EDT).
#
# The first offset to be defined is treated as the offset that applies
# until the first transition. This will usually be in Local Mean Time (LMT).
#
# ArgumentError will be raised if the id is already defined.
def offset(id, utc_offset, std_offset, abbreviation)
raise ArgumentError, 'Offset already defined' if @offsets.has_key?(id)
offset = TimezoneOffsetInfo.new(utc_offset, std_offset, abbreviation)
@offsets[id] = offset
@previous_offset = offset unless @previous_offset
end
# Defines a transition. Transitions must be defined in chronological order.
# ArgumentError will be raised if a transition is added out of order.
# offset_id refers to an id defined with offset. ArgumentError will be
# raised if the offset_id cannot be found. numerator_or_time and
# denominator specify the time the transition occurs as. See
# TimezoneTransitionInfo for more detail about specifying times.
def transition(year, month, offset_id, numerator_or_time, denominator = nil)
offset = @offsets[offset_id]
raise ArgumentError, 'Offset not found' unless offset
if @transitions_index
if year < @last_year || (year == @last_year && month < @last_month)
raise ArgumentError, 'Transitions must be increasing date order'
end
# Record the position of the first transition with this index.
index = transition_index(year, month)
@transitions_index[index] ||= @transitions.length
# Fill in any gaps
(index - 1).downto(0) do |i|
break if @transitions_index[i]
@transitions_index[i] = @transitions.length
end
else
@transitions_index = [@transitions.length]
@start_year = year
@start_month = month
end
@transitions << TimezoneTransitionInfo.new(offset, @previous_offset,
numerator_or_time, denominator)
@last_year = year
@last_month = month
@previous_offset = offset
end
# Returns the TimezonePeriod for the given UTC time.
# Raises NoOffsetsDefined if no offsets have been defined.
def period_for_utc(utc)
unless @transitions.empty?
utc = TimeOrDateTime.wrap(utc)
index = transition_index(utc.year, utc.mon)
start_transition = nil
start = transition_before_end(index)
if start
start.downto(0) do |i|
if @transitions[i].at <= utc
start_transition = @transitions[i]
break
end
end
end
end_transition = nil
start = transition_after_start(index)
if start
start.upto(@transitions.length - 1) do |i|
if @transitions[i].at > utc
end_transition = @transitions[i]
break
end
end
end
if start_transition || end_transition
TimezonePeriod.new(start_transition, end_transition)
else
# Won't happen since there are transitions. Must always find one
# transition that is either >= or < the specified time.
raise 'No transitions found in search'
end
else
raise NoOffsetsDefined, 'No offsets have been defined' unless @previous_offset
TimezonePeriod.new(nil, nil, @previous_offset)
end
end
# Returns the set of TimezonePeriods for the given local time as an array.
# Results returned are ordered by increasing UTC start date.
# Returns an empty array if no periods are found for the given time.
# Raises NoOffsetsDefined if no offsets have been defined.
def periods_for_local(local)
unless @transitions.empty?
local = TimeOrDateTime.wrap(local)
index = transition_index(local.year, local.mon)
result = []
start_index = transition_after_start(index - 1)
if start_index && @transitions[start_index].local_end > local
if start_index > 0
if @transitions[start_index - 1].local_start <= local
result << TimezonePeriod.new(@transitions[start_index - 1], @transitions[start_index])
end
else
result << TimezonePeriod.new(nil, @transitions[start_index])
end
end
end_index = transition_before_end(index + 1)
if end_index
start_index = end_index unless start_index
start_index.upto(transition_before_end(index + 1)) do |i|
if @transitions[i].local_start <= local
if i + 1 < @transitions.length
if @transitions[i + 1].local_end > local
result << TimezonePeriod.new(@transitions[i], @transitions[i + 1])
end
else
result << TimezonePeriod.new(@transitions[i], nil)
end
end
end
end
result
else
raise NoOffsetsDefined, 'No offsets have been defined' unless @previous_offset
[TimezonePeriod.new(nil, nil, @previous_offset)]
end
end
private
# Returns the index into the @transitions_index array for a given year
# and month.
def transition_index(year, month)
index = (year - @start_year) * 2
index += 1 if month > 6
index -= 1 if @start_month > 6
index
end
# Returns the index into @transitions of the first transition that occurs
# on or after the start of the given index into @transitions_index.
# Returns nil if there are no such transitions.
def transition_after_start(index)
if index >= @transitions_index.length
nil
else
index = 0 if index < 0
@transitions_index[index]
end
end
# Returns the index into @transitions of the first transition that occurs
# before the end of the given index into @transitions_index.
# Returns nil if there are no such transitions.
def transition_before_end(index)
index = index + 1
if index <= 0
nil
elsif index >= @transitions_index.length
@transitions.length - 1
else
@transitions_index[index] - 1
end
end
end
end
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