diff --git a/ChangeLog b/ChangeLog
index bb6755ad3..b5be44483 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,7 @@
+Thu Jan  6 13:45:35 2005  Tanaka Akira  <akr@m17n.org>
+
+	* lib/time.rb: recognize +00:00 and GMT as a localtime.
+
 Thu Jan  6 07:58:28 2005  Dave Thomas  <dave@pragprog.com>
 
 	* lib/rdoc/usage.rb (RDoc::RDoc.usage_no_exit): Allow for colons
diff --git a/lib/time.rb b/lib/time.rb
index b045203ea..e0d831d3b 100644
--- a/lib/time.rb
+++ b/lib/time.rb
@@ -60,7 +60,7 @@ class << Time
       'MST' => -7, 'MDT' => -6,
       'PST' => -8, 'PDT' => -7,
       # Following definition of military zones is original one.
-      # See RFC 1123 and RFC 2822 for the error of RFC 822.
+      # See RFC 1123 and RFC 2822 for the error in RFC 822.
       'A' => +1, 'B' => +2, 'C' => +3, 'D' => +4,  'E' => +5,  'F' => +6, 
       'G' => +7, 'H' => +8, 'I' => +9, 'K' => +10, 'L' => +11, 'M' => +12,
       'N' => -1, 'O' => -2, 'P' => -3, 'Q' => -4,  'R' => -5,  'S' => -6, 
@@ -83,6 +83,17 @@ def zone_offset(zone, year=Time.now.year)
       off
     end
 
+    def zone_utc?(zone)
+      # * +0000 means localtime. [RFC 2822]
+      # * GMT is a localtime abbreviation in Europe/London, etc.
+      if /\A(?:-00:00|-0000|-00|UTC|Z|UT)\z/i =~ zone
+        true
+      else
+        false
+      end
+    end
+    private :zone_utc?
+
     #
     # Parses +date+ using ParseDate.parsedate and converts it to a Time object.
     #
@@ -160,7 +171,7 @@ def parse(date, now=Time.now)
 
       if off
         t = Time.utc(year, mon, day, hour, min, sec) - off
-        t.localtime if off != 0
+        t.localtime if !zone_utc?(zone)
         t
       else
         Time.local(year, mon, day, hour, min, sec)
@@ -212,8 +223,8 @@ def rfc2822(date)
                end
 
         t = Time.utc(year, mon, day, hour, min, sec)
-        offset = zone_offset(zone)
-	t = (t - offset).localtime if offset != 0 || zone == '+0000'
+        t -= zone_offset(zone)
+        t.localtime if !zone_utc?(zone)
 	t
       else
         raise ArgumentError.new("not RFC 2822 compliant date: #{date.inspect}")
@@ -612,6 +623,19 @@ def test_invalid
       assert_raise(ArgumentError) { Time.rfc2822("\307\341\314\343\332\311, 30 \344\346\335\343\310\321 2001 10:01:06") }
       assert_raise(ArgumentError) { Time.rfc2822("=?iso-8859-1?Q?(=BF=E5),?= 12  =?iso-8859-1?Q?9=B7=EE?= 2001 14:52:41\n+0900 (JST)") }
     end
+
+    def test_zone_0000
+      assert_equal(true, Time.parse("2000-01-01T00:00:00Z").utc?)
+      assert_equal(true, Time.parse("2000-01-01T00:00:00-00:00").utc?)
+      assert_equal(false, Time.parse("2000-01-01T00:00:00+00:00").utc?)
+      assert_equal(false, Time.parse("Sat, 01 Jan 2000 00:00:00 GMT").utc?)
+      assert_equal(true, Time.parse("Sat, 01 Jan 2000 00:00:00 -0000").utc?)
+      assert_equal(false, Time.parse("Sat, 01 Jan 2000 00:00:00 +0000").utc?)
+      assert_equal(false, Time.rfc2822("Sat, 01 Jan 2000 00:00:00 GMT").utc?)
+      assert_equal(true, Time.rfc2822("Sat, 01 Jan 2000 00:00:00 -0000").utc?)
+      assert_equal(false, Time.rfc2822("Sat, 01 Jan 2000 00:00:00 +0000").utc?)
+      assert_equal(true, Time.rfc2822("Sat, 01 Jan 2000 00:00:00 UTC").utc?)
+    end
   end
 
 end