timezone_period.rb in tzinfo-0.2.0

- old
+ new

@@ -1,7 +1,7 @@
 #--
-# Copyright (c) 2005 Philip Ross
+# Copyright (c) 2005-2006 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
@@ -18,73 +18,20 @@
 # 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/offset_rationals'
+require 'tzinfo/time_or_datetime'
+
 module TZInfo
   # A period of time in a timezone where the same offset from UTC applies.
+  #
+  # All the methods that take times accept instances of Time, DateTime or
+  # integer timestamps.
   class TimezonePeriod
-    
-    # A cache of pre-reduced Rationals for each half-hour between -12 and +12.
-    # This is used to save time when loading a TimezonePeriod.
-    @@rational_cache = {
-      -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)}
-    
-    # Start time of the period (UTC). May be nil if unbounded.
-    attr_reader :utc_start
-    
-    # End time of the period (UTC). May be nil if unbounded.
-    attr_reader :utc_end
-    
+
     # Base offset of the timezone from UTC (seconds).
     attr_reader :utc_offset
     
     # 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. 
@@ -92,43 +39,59 @@
     attr_reader :std_offset
     
     # 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.
-    attr_reader :zone_identifier
+    attr_reader :zone_identifier        
     
-    # Start time of the period (local time). May be nil if unbounded.
-    attr_reader :local_start
+    # Total offset from UTC (seconds). Equal to utc_offset + std_offset.
+    attr_reader :utc_total_offset
     
-    # End time of the period (local time). May be nil if unbounded.
-    attr_reader :local_end
-    
     # Initializes a new TimezonePeriod.
     def initialize(utc_start, utc_end, utc_offset, std_offset, zone_identifier)
-      @utc_start = utc_start
-      @utc_end = utc_end
+      @utc_start = utc_start.nil? ? nil : TimeOrDateTime.wrap(utc_start)
+      @utc_end = utc_end.nil? ? nil : TimeOrDateTime.wrap(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)             
+      @utc_total_offset_rational = nil
+              
+      # Use add_with_convert to use DateTime based TimeOrDateTimes if we run
+      # off the range of Time.
+      @local_start = @utc_start.nil? ? nil : @utc_start.add_with_convert(@utc_total_offset)
+      @local_end = @utc_end.nil? ? nil : @utc_end.add_with_convert(@utc_total_offset)             
     end
-    
-    # Total offset from UTC (seconds). Equal to utc_offset + std_offset.
-    def utc_total_offset
-      @utc_total_offset
-    end
-    
+            
     # Total offset from UTC (days). Result is a Rational.
     def utc_total_offset_rational
+      if @utc_total_offset_rational.nil?
+        @utc_total_offset_rational = OffsetRationals.rational_for_offset(@utc_total_offset) 
+      end
       @utc_total_offset_rational
     end
     
+    # Start time of the period (UTC). May be nil if unbounded.
+    def utc_start
+      @utc_start.nil? ? nil : @utc_start.to_datetime
+    end
+    
+    # End time of the period (UTC). May be nil if unbounded.
+    def utc_end
+      @utc_end.nil? ? nil : @utc_end.to_datetime
+    end
+    
+    # Start time of the period (local time). May be nil if unbounded.
+    def local_start
+      @local_start.nil? ? nil : @local_start.to_datetime
+    end
+    
+    # End time of the period (local time). May be nil if unbounded.
+    def local_end
+      @local_end.nil? ? nil : @local_end.to_datetime
+    end
+    
     # true if daylight savings is in effect for this period; otherwise false.
     def dst?
       std_offset != 0
     end
     
@@ -136,40 +99,44 @@
     def valid_for_utc?(utc)
       utc_after_start?(utc) && utc_before_end?(utc) 
     end
     
     # true if the given utc DateTime is after the start of the period (inclusive); otherwise false.
-    def utc_after_start?(utc)
+    def utc_after_start?(utc)                
       @utc_start.nil? || @utc_start <= utc
     end
     
     # true if the given utc DateTime is before the end of the period (exclusive); otherwise false.
-    def utc_before_end?(utc)
+    def utc_before_end?(utc)           
       @utc_end.nil? || @utc_end > utc
     end
     
     # true if this period is valid for the given local DateTime; otherwise false.
-    def valid_for_local?(local)
+    def valid_for_local?(local)      
       local_after_start?(local) && local_before_end?(local) 
     end
     
     # true if the given local DateTime is after the start of the period (inclusive); otherwise false.
-    def local_after_start?(local)
+    def local_after_start?(local)                
       @local_start.nil? || @local_start <= local
     end
     
     # true if the given local DateTime is before the end of the period (exclusive); otherwise false.
-    def local_before_end?(local)
+    def local_before_end?(local)               
       @local_end.nil? || @local_end > local
     end
     
     # Converts a UTC DateTime to local time based on the offset of this period.
     def to_local(utc)
-      utc + utc_total_offset_rational
+      TimeOrDateTime.wrap(utc) {|utc|
+        utc + utc_total_offset
+      }
     end
     
     # Converts a local DateTime to UTC based on the offset of this period.
     def to_utc(local)
-      local - utc_total_offset_rational
+      TimeOrDateTime.wrap(local) {|local|
+        local - utc_total_offset
+      }
     end
   end
 end