Class: IOStreams::Tabular::Utility::CSVRow

Inherits:
CSV
  • Object
show all
Defined in:
lib/io_streams/tabular/utility/csv_row.rb

Overview

For parsing a single line of CSV at a time 2 to 3 times better performance than CSV.parse_line and considerably less garbage collection required.

Note: Only used prior to Ruby 2.6

Constant Summary collapse

UTF8_ENCODING = 
Encoding.find("UTF-8").freeze

Instance Method Summary collapse

Constructor Details

#initialize(encoding = UTF8_ENCODING) ⇒ CSVRow

Returns a new instance of CSVRow.



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# File 'lib/io_streams/tabular/utility/csv_row.rb', line 13

def initialize(encoding = UTF8_ENCODING)
  @io = StringIO.new("".force_encoding(encoding))
  super(@io, row_sep: "")
end

Instance Method Details

#parse(line) ⇒ Object

Parse a single line of CSV data Parameters

line [String]
  A single line of CSV data without any line terminators

Raises:

  • (MalformedCSVError) 


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# File 'lib/io_streams/tabular/utility/csv_row.rb', line 22

def parse(line)
  return if IOStreams::Utils.blank?(line)
  return if @skip_lines&.match(line)

  in_extended_col = false
  csv             = []
  parts           = line.split(@col_sep, -1)
  csv << nil if parts.empty?

  # This loop is the hot path of csv parsing. Some things may be non-dry
  # for a reason. Make sure to benchmark when refactoring.
  parts.each do |part|
    if in_extended_col
      # If we are continuing a previous column
      if part[-1] == @quote_char && part.count(@quote_char).odd?
        # extended column ends
        csv.last << part[0..-2]
        raise MalformedCSVError, "Missing or stray quote in line #{lineno + 1}" if csv.last =~ @parsers[:stray_quote]

        csv.last.gsub!(@quote_char * 2, @quote_char)
        in_extended_col = false
      else
        csv.last << part
        csv.last << @col_sep
      end
    elsif part[0] == @quote_char
      # If we are starting a new quoted column
      if part[-1] != @quote_char || part.count(@quote_char).odd?
        # start an extended column
        csv << part[1..-1]
        csv.last << @col_sep
        in_extended_col = true
      else
        # regular quoted column
        csv << part[1..-2]
        raise MalformedCSVError, "Missing or stray quote in line #{lineno + 1}" if csv.last =~ @parsers[:stray_quote]

        csv.last.gsub!(@quote_char * 2, @quote_char)
      end
    elsif part =~ @parsers[:quote_or_nl]
      # Unquoted field with bad characters.
      if part =~ @parsers[:nl_or_lf]
        raise MalformedCSVError, "Unquoted fields do not allow \\r or \\n (line #{lineno + 1})."
      else
        raise MalformedCSVError, "Illegal quoting in line #{lineno + 1}."
      end
    else
      # Regular ole unquoted field.
      csv << (part.empty? ? nil : part)
    end
  end

  # Replace tacked on @col_sep with @row_sep if we are still in an extended
  # column.
  csv[-1][-1] = @row_sep if in_extended_col

  raise MalformedCSVError, "Unclosed quoted field on line #{lineno + 1}." if in_extended_col

  @lineno += 1

  # save fields unconverted fields, if needed...
  unconverted = csv.dup if @unconverted_fields

  # convert fields, if needed...
  csv         = convert_fields(csv) unless @use_headers || @converters.empty?
  # parse out header rows and handle CSV::Row conversions...
  csv         = parse_headers(csv) if @use_headers

  # inject unconverted fields and accessor, if requested...
  add_unconverted_fields(csv, unconverted) if @unconverted_fields && (!csv.respond_to? :unconverted_fields)

  csv
end

#render(row) ⇒ Object Also known as: to_csv

Return the supplied array as a single line CSV string.



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# File 'lib/io_streams/tabular/utility/csv_row.rb', line 97

def render(row)
  row.map(&@quote).join(@col_sep) + @row_sep # quote and separate
end