Don't build quoted_fields array when not needed

benchmark/convert_nil.yaml

@@ -4,6 +4,8 @@ contexts:
       csv: 3.0.1
   - gems:
       csv: 3.0.2
+  - gems:
+      csv: 3.3.0
   - name: "master"
     prelude: |
       $LOAD_PATH.unshift(File.expand_path("lib"))

benchmark/parse.yaml

@@ -4,6 +4,8 @@ contexts:
       csv: 3.0.1
   - gems:
       csv: 3.0.2
+  - gems:
+      csv: 3.3.0
   - name: "master"
     prelude: |
       $LOAD_PATH.unshift(File.expand_path("lib"))

benchmark/parse_liberal_parsing.yaml

@@ -2,6 +2,8 @@ loop_count: 100
 contexts:
   - gems:
       csv: 3.0.2
+  - gems:
+      csv: 3.3.0
   - name: "master"
     prelude: |
       $LOAD_PATH.unshift(File.expand_path("lib"))

benchmark/parse_quote_char_nil.yaml

@@ -1,5 +1,7 @@
 loop_count: 100
 contexts:
+  - gems:
+      csv: 3.3.0
   - name: "master"
     prelude: |
       $LOAD_PATH.unshift(File.expand_path("lib"))

benchmark/parse_strip.yaml

@@ -1,5 +1,7 @@
 loop_count: 100
 contexts:
+  - gems:
+      csv: 3.3.0
   - name: "master"
     prelude: |
       $LOAD_PATH.unshift(File.expand_path("lib"))

benchmark/read.yaml

@@ -4,6 +4,8 @@ contexts:
       csv: 3.0.1
   - gems:
       csv: 3.0.2
+  - gems:
+      csv: 3.3.0
   - name: "master"
     prelude: |
       $LOAD_PATH.unshift(File.expand_path("lib"))

benchmark/shift.yaml

@@ -4,6 +4,8 @@ contexts:
       csv: 3.0.1
   - gems:
       csv: 3.0.2
+  - gems:
+      csv: 3.3.0
   - name: "master"
     prelude: |
       $LOAD_PATH.unshift(File.expand_path("lib"))

benchmark/write.yaml

@@ -4,6 +4,8 @@ contexts:
       csv: 3.0.1
   - gems:
       csv: 3.0.2
+  - gems:
+      csv: 3.3.0
   - name: "master"
     prelude: |
       $LOAD_PATH.unshift(File.expand_path("lib"))

lib/csv.rb

@@ -959,6 +959,12 @@ def initialize(encoding, line_number)
     write_empty_value:  "",
   }.freeze
 
+  module NoQuotedFields # :nodoc:
+    def self.[](_index)
+      false
+    end
+  end
+
   class << self
     # :call-seq:
     #   instance(string, **options)

lib/csv/fields_converter.rb

@@ -44,7 +44,7 @@ def empty?
       @converters.empty?
     end
 
-    def convert(fields, headers, lineno, quoted_fields)
+    def convert(fields, headers, lineno, quoted_fields = NoQuotedFields)
       return fields unless need_convert?
 
       fields.collect.with_index do |field, index|

lib/csv/parser.rb

@@ -767,7 +767,7 @@ def prepare_header
       case headers
       when Array
         @raw_headers = headers
-        quoted_fields = [false] * @raw_headers.size
+        quoted_fields = NoQuotedFields
         @use_headers = true
       when String
         @raw_headers, quoted_fields = parse_headers(headers)
@@ -944,11 +944,9 @@ 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)
@@ -962,7 +960,7 @@ def parse_no_quote(&block)
           end
         end
         @last_line = original_line
-        emit_row(row, quoted_fields, &block)
+        emit_row(row, &block)
       end
     end
 
@@ -984,7 +982,7 @@ def parse_quotable_loose(&block)
             next
           end
           row = []
-          quoted_fields = []
+          quoted_fields = NoQuotedFields
         elsif line.include?(@cr) or line.include?(@lf)
           @scanner.keep_back
           @need_robust_parsing = true
@@ -1046,13 +1044,13 @@ 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
@@ -1257,7 +1255,7 @@ def start_row
       @scanner.keep_start
     end
 
-    def emit_row(row, quoted_fields, &block)
+    def emit_row(row, quoted_fields = NoQuotedFields, &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