* lib/csv.rb: Upgrading output encoding as needed. [ruby-core:33135]

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@29808 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

1 files changed, 20 insertions, 8 deletions

diff --git a/lib/csv.rb b/lib/csv.rb
index fed35d2a81..fe7309009b 100644
--- a/lib/csv.rb
+++ b/lib/csv.rb
@@ -1562,9 +1562,10 @@ class CSV
     options = DEFAULT_OPTIONS.merge(options)
 
     # create the IO object we will read from
-    @io       =   if data.is_a? String then StringIO.new(data) else data end
+    @io       = data.is_a?(String) ? StringIO.new(data) : data
     # honor the IO encoding if we can, otherwise default to ASCII-8BIT
-    @encoding = raw_encoding || Encoding.default_internal || Encoding.default_external
+    @encoding = raw_encoding || Encoding.default_internal ||
+                                Encoding.default_external
     #
     # prepare for building safe regular expressions in the target encoding,
     # if we can transcode the needed characters
@@ -1711,7 +1712,15 @@ class CSV
     @headers =  row if header_row?
     @lineno  += 1
 
-    @io << row.map(&@quote).join(@col_sep) + @row_sep  # quote and separate
+    output = row.map(&@quote).join(@col_sep) + @row_sep  # quote and separate
+    if @io.is_a?(StringIO)             and
+       output.encoding != raw_encoding and
+       ( compatible_encoding = Encoding.compatible?( @io.string.encoding,
+                                                     output.encoding ) )
+      @io = StringIO.new(@io.string.force_encoding(compatible_encoding))
+      @io.seek(0, IO::SEEK_END)
+    end
+    @io << output
 
     self  # for chaining
   end
@@ -2043,11 +2052,13 @@ class CSV
     @row_sep = @row_sep.to_s.encode(@encoding)
 
     # establish quoting rules
-    @force_quotes = options.delete(:force_quotes)
-    do_quote      = lambda do |field|
-      @quote_char                                      +
-      String(field).gsub(@quote_char, @quote_char * 2) +
-      @quote_char
+    @force_quotes   = options.delete(:force_quotes)
+    do_quote        = lambda do |field|
+      field         = String(field)
+      encoded_quote = @quote_char.encode(field.encoding)
+      encoded_quote                                +
+      field.gsub(encoded_quote, encoded_quote * 2) +
+      encoded_quote
     end
     quotable_chars = encode_str("\r\n", @col_sep, @quote_char)
     @quote         = if @force_quotes
@@ -2297,6 +2308,7 @@ class CSV
   end
 
   private
+
   def raw_encoding
     if @io.respond_to? :internal_encoding
       @io.internal_encoding || @io.external_encoding