Read EOCD record for Zip64 files.

Means we actually read in the file-level comment now!

Fixes rubyzip#492.

lib/zip/central_directory.rb

@@ -126,14 +126,21 @@ def unpack_e_o_c_d(buffer) #:nodoc:
       buf = buffer.slice(index, buffer.size)
 
       _, # END_OF_CDS signature. We know we have this at this point.
-      @number_of_this_disk,
-      @number_of_disk_with_start_of_cdir,
-      @total_number_of_entries_in_cdir_on_this_disk,
-      @size,
-      @size_in_bytes,
-      @cdir_offset,
+      num_disk,
+      num_disk_cdir,
+      num_cdir_disk,
+      num_entries,
+      size_in_bytes,
+      cdir_offset,
       comment_length = buf.unpack('VvvvvVVv')
 
+      @number_of_this_disk = num_disk unless num_disk == 0xFFFF
+      @number_of_disk_with_start_of_cdir = num_disk_cdir unless num_disk_cdir == 0xFFFF
+      @total_number_of_entries_in_cdir_on_this_disk = num_cdir_disk unless num_cdir_disk == 0xFFFF
+      @size = num_entries unless num_entries == 0xFFFF
+      @size_in_bytes = size_in_bytes unless size_in_bytes == 0xFFFFFFFF
+      @cdir_offset = cdir_offset unless cdir_offset == 0xFFFFFFFF
+
       @comment = if comment_length.positive?
                    buf.slice(STATIC_EOCD_SIZE, comment_length)
                  else
@@ -182,11 +189,8 @@ def read_local_extra_field(io)
 
     def read_from_stream(io) #:nodoc:
       buf = start_buf(io)
-      if zip64_file?(buf)
-        unpack_64_e_o_c_d(buf)
-      else
-        unpack_e_o_c_d(buf)
-      end
+      unpack_64_e_o_c_d(buf) if zip64_file?(buf)
+      unpack_e_o_c_d(buf)
       read_central_directory_entries(io)
     end
 

test/zip64_full_test.rb

@@ -19,8 +19,11 @@ def test_large_zip_file
     ::Zip.write_zip64_support = true
     first_text = 'starting out small'
     last_text = 'this tests files starting after 4GB in the archive'
+    comment_text = 'this is a file comment in a zip64 archive'
 
     ::Zip::File.open(HUGE_ZIP, ::Zip::File::CREATE) do |zf|
+      zf.comment = comment_text
+
       zf.get_output_stream('first_file.txt') do |io|
         io.write(first_text)
       end
@@ -44,6 +47,7 @@ def test_large_zip_file
       )
       assert_equal(first_text, zf.read('first_file.txt'))
       assert_equal(last_text, zf.read('last_file.txt'))
+      assert_equal(comment_text, zf.comment)
     end
 
     # NOTE: if this fails, be sure you have UnZip version 6.0 or newer