Set entry names encoding appropriately.

If we don't set this then we can't do things like file.exists?("Résumé.txt")
without specifically forcing it to ASCII-8BIT, which is unnecessarily clunky:

file.exists?("Résumé.txt".force_encoding("ASCII-8BIT"))

This is because entry names are always read as ASCII-8BIT even if the EFS bit is
set. This patch fixes that.

Tests added/updated to make sure that this works for both files and streams.

lib/zip/entry.rb

@@ -232,11 +232,9 @@ def read_local_entry(io) #:nodoc:all
       end
       set_time(@last_mod_date, @last_mod_time)
 
-      @name = io.read(@name_length)
+      @name = read_name(io)
       extra = io.read(@extra_length)
 
-      @name.gsub!('\\', '/')
-
       if extra && extra.bytesize != @extra_length
         raise ::Zip::Error, "Truncated local zip entry header"
       else
@@ -362,7 +360,7 @@ def read_c_dir_entry(io) #:nodoc:all
       unpack_c_dir_entry(static_sized_fields_buf)
       check_c_dir_entry_signature
       set_time(@last_mod_date, @last_mod_time)
-      @name = io.read(@name_length).gsub('\\', '/')
+      @name = read_name(io)
       read_c_dir_extra_field(io)
       @comment = io.read(@comment_length)
       check_c_dir_entry_comment_size
@@ -570,6 +568,11 @@ def unicode_name?
 
     private
 
+    def read_name(io)
+      name = io.read(@name_length).gsub('\\', '/')
+      unicode_name? ? name.force_encoding("UTF-8") : name
+    end
+
     def set_time(binary_dos_date, binary_dos_time)
       @time = ::Zip::DOSTime.parse_binary_dos_format(binary_dos_date, binary_dos_time)
     rescue ArgumentError

test/unicode_file_names_and_comments_test.rb

@@ -4,7 +4,8 @@
 
 class ZipUnicodeFileNamesAndComments < MiniTest::Test
 
-  FILENAME = File.join(File.dirname(__FILE__), "test1.zip")
+  STREAM_FILENAME = File.join(File.dirname(__FILE__), "test1.zip")
+  UNICODE_FILENAME = File.join(File.dirname(__FILE__), "data", "unicode.zip")
 
   ENTRIES = [
     "текстовыйфайл.txt", "Résumé.txt", "슬레이어스휘.txt",
@@ -14,25 +15,35 @@ class ZipUnicodeFileNamesAndComments < MiniTest::Test
   def test_unicode_with_streams
     Zip.unicode_names = true
 
-    stream = ::Zip::OutputStream.open(FILENAME) do |io|
+    stream = ::Zip::OutputStream.open(STREAM_FILENAME) do |io|
       ENTRIES.each do |filename|
         io.put_next_entry(filename)
         io.write(filename)
       end
     end
     assert(!stream.nil?)
 
-    ::Zip::InputStream.open(FILENAME) do |io|
+    ::Zip::InputStream.open(STREAM_FILENAME) do |io|
       ENTRIES.each do |filename|
         entry = io.get_next_entry
         assert(entry.unicode_name?)
-        entry_name = entry.name
-        entry_name = entry_name.force_encoding("UTF-8") if RUBY_VERSION >= '1.9'
-        assert(filename == entry_name)
+        assert_equal(filename, entry.name)
       end
     end
 
-    ::File.unlink(FILENAME)
+    ::File.unlink(STREAM_FILENAME)
+  end
+
+  def test_unicode_from_file
+    ::Zip::File.open(UNICODE_FILENAME) do |f|
+      ENTRIES.each do |name|
+        assert(f.file.exists?(name))
+      end
+
+      f.each_entry do |entry|
+        assert(entry.unicode_name?)
+      end
+    end
   end
 
 end