Don't build quoted_fields array when not needed

Author: marshall-lee

lib/csv/fields_converter.rb

@@ -4,6 +4,13 @@ class CSV
   # Note: Don't use this class directly. This is an internal class.
   class FieldsConverter
     include Enumerable
+
+    NO_QUOTED_FIELDS = [] # :nodoc:
+    def NO_QUOTED_FIELDS.[](_index)
+      false
+    end
+    NO_QUOTED_FIELDS.freeze
+
     #
     # A CSV::FieldsConverter is a data structure for storing the
     # fields converter properties to be passed as a parameter
@@ -44,7 +51,7 @@ def empty?
       @converters.empty?
     end
 
-    def convert(fields, headers, lineno, quoted_fields)
+    def convert(fields, headers, lineno, quoted_fields=NO_QUOTED_FIELDS)
       return fields unless need_convert?
 
       fields.collect.with_index do |field, index|

lib/csv/parser.rb

@@ -757,7 +757,7 @@ def prepare_header
       case headers
       when Array
         @raw_headers = headers
-        quoted_fields = [false] * @raw_headers.size
+        quoted_fields = FieldsConverter::NO_QUOTED_FIELDS
         @use_headers = true
       when String
         @raw_headers, quoted_fields = parse_headers(headers)
@@ -941,11 +941,9 @@ def parse_no_quote(&block)
         if line.empty?
           next if @skip_blanks
           row = []
-          quoted_fields = []
         else
           line = strip_value(line)
           row = line.split(@split_column_separator, -1)
-          quoted_fields = [false] * row.size
           if @max_field_size
             row.each do |column|
               validate_field_size(column)
@@ -959,7 +957,7 @@ def parse_no_quote(&block)
           end
         end
         @last_line = original_line
-        emit_row(row, quoted_fields, &block)
+        emit_row(row, &block)
       end
     end
 
@@ -981,7 +979,7 @@ def parse_quotable_loose(&block)
             next
           end
           row = []
-          quoted_fields = []
+          quoted_fields = FieldsConverter::NO_QUOTED_FIELDS
         elsif line.include?(@cr) or line.include?(@lf)
           @scanner.keep_back
           @parse_method = :parse_quotable_robust
@@ -1043,13 +1041,13 @@ def parse_quotable_robust(&block)
           quoted_fields << @quoted_column_value
         elsif parse_row_end
           if row.empty? and value.nil?
-            emit_row([], [], &block) unless @skip_blanks
+            emit_row(row, &block) unless @skip_blanks
           else
             row << value
             quoted_fields << @quoted_column_value
             emit_row(row, quoted_fields, &block)
             row = []
-            quoted_fields = []
+            quoted_fields.clear
           end
           skip_needless_lines
           start_row
@@ -1254,7 +1252,7 @@ def start_row
       @scanner.keep_start
     end
 
-    def emit_row(row, quoted_fields, &block)
+    def emit_row(row, quoted_fields=FieldsConverter::NO_QUOTED_FIELDS, &block)
       @lineno += 1
 
       raw_row = row

lib/csv/writer.rb

@@ -40,8 +40,7 @@ def <<(row)
       @lineno += 1
 
       if @fields_converter
-        quoted_fields = [false] * row.size
-        row = @fields_converter.convert(row, nil, lineno, quoted_fields)
+        row = @fields_converter.convert(row, nil, lineno)
       end
 
       i = -1