Elep

# encoding: US-ASCII
# frozen_string_literal: true
# = csv.rb -- CSV Reading and Writing
#
# Created by James Edward Gray II on 2005-10-31.
#
# See CSV for documentation.
#
# == Description
#
# Welcome to the new and improved CSV.
#
# This version of the CSV library began its life as FasterCSV. FasterCSV was
# intended as a replacement to Ruby's then standard CSV library. It was
# designed to address concerns users of that library had and it had three
# primary goals:
#
# 1. Be significantly faster than CSV while remaining a pure Ruby library.
# 2. Use a smaller and easier to maintain code base. (FasterCSV eventually
# grew larger, was also but considerably richer in features. The parsing
# core remains quite small.)
# 3. Improve on the CSV interface.
#
# Obviously, the last one is subjective. I did try to defer to the original
# interface whenever I didn't have a compelling reason to change it though, so
# hopefully this won't be too radically different.
#
# We must have met our goals because FasterCSV was renamed to CSV and replaced
# the original library as of Ruby 1.9. If you are migrating code from 1.8 or
# earlier, you may have to change your code to comply with the new interface.
#
# == What's the Different From the Old CSV?
#
# I'm sure I'll miss something, but I'll try to mention most of the major
# differences I am aware of, to help others quickly get up to speed:
#
# === CSV Parsing
#
# * This parser is m17n aware. See CSV for full details.
# * This library has a stricter parser and will throw MalformedCSVErrors on
# problematic data.
# * This library has a less liberal idea of a line ending than CSV. What you
# set as the <tt>:row_sep</tt> is law. It can auto-detect your line endings
# though.
# * The old library returned empty lines as <tt>[nil]</tt>. This library calls
# them <tt>[]</tt>.
# * This library has a much faster parser.
#
# === Interface
#
# * CSV now uses Hash-style parameters to set options.
# * CSV no longer has generate_row() or parse_row().
# * The old CSV's Reader and Writer classes have been dropped.
# * CSV::open() is now more like Ruby's open().
# * CSV objects now support most standard IO methods.
# * CSV now has a new() method used to wrap objects like String and IO for
# reading and writing.
# * CSV::generate() is different from the old method.
# * CSV no longer supports partial reads. It works line-by-line.
# * CSV no longer allows the instance methods to override the separators for
# performance reasons. They must be set in the constructor.
#
# If you use this library and find yourself missing any functionality I have
# trimmed, please {let me know}[mailto:james@grayproductions.net].
#
# == Documentation
#
# See CSV for documentation.
#
# == What is CSV, really?
#
# CSV maintains a pretty strict definition of CSV taken directly from
# {the RFC}[http://www.ietf.org/rfc/rfc4180.txt]. I relax the rules in only one
# place and that is to make using this library easier. CSV will parse all valid
# CSV.
#
# What you don't want to do is to feed CSV invalid data. Because of the way the
# CSV format works, it's common for a parser to need to read until the end of
# the file to be sure a field is invalid. This consumes a lot of time and memory.
#
# Luckily, when working with invalid CSV, Ruby's built-in methods will almost
# always be superior in every way. For example, parsing non-quoted fields is as
# easy as:
#
# data.split(",")
#
# == Questions and/or Comments
#
# Feel free to email {James Edward Gray II}[mailto:james@grayproductions.net]
# with any questions.

require "forwardable"
require "English"
require "date"
require "stringio"

require_relative "csv/fields_converter"
require_relative "csv/match_p"
require_relative "csv/parser"
require_relative "csv/row"
require_relative "csv/table"
require_relative "csv/writer"

using CSV::MatchP if CSV.const_defined?(:MatchP)

#
# This class provides a complete interface to CSV files and data. It offers
# tools to enable you to read and write to and from Strings or IO objects, as
# needed.
#
# The most generic interface of the library is:
#
# csv = CSV.new(string_or_io, **options)
#
# # Reading: IO object should be open for read
# csv.read # => array of rows
# # or
# csv.each do |row|
# # ...
# end
# # or
# row = csv.shift
#
# # Writing: IO object should be open for write
# csv << row
#
# There are several specialized class methods for one-statement reading or writing,
# described in the Specialized Methods section.
#
# If a String is passed into ::new, it is internally wrapped into a StringIO object.
#
# +options+ can be used for specifying the particular CSV flavor (column
# separators, row separators, value quoting and so on), and for data conversion,
# see Data Conversion section for the description of the latter.
#
# == Specialized Methods
#
# === Reading
#
# # From a file: all at once
# arr_of_rows = CSV.read("path/to/file.csv", **options)
# # iterator-style:
# CSV.foreach("path/to/file.csv", **options) do |row|
# # ...
# end
#
# # From a string
# arr_of_rows = CSV.parse("CSV,data,String", **options)
# # or
# CSV.parse("CSV,data,String", **options) do |row|
# # ...
# end
#
# === Writing
#
# # To a file
# CSV.open("path/to/file.csv", "wb") do |csv|
# csv << ["row", "of", "CSV", "data"]
# csv << ["another", "row"]
# # ...
# end
#
# # To a String
# csv_string = CSV.generate do |csv|
# csv << ["row", "of", "CSV", "data"]
# csv << ["another", "row"]
# # ...
# end
#
# === Shortcuts
#
# # Core extensions for converting one line
# csv_string = ["CSV", "data"].to_csv # to CSV
# csv_array = "CSV,String".parse_csv # from CSV
#
# # CSV() method
# CSV { |csv_out| csv_out << %w{my data here} } # to $stdout
# CSV(csv = "") { |csv_str| csv_str << %w{my data here} } # to a String
# CSV($stderr) { |csv_err| csv_err << %w{my data here} } # to $stderr
# CSV($stdin) { |csv_in| csv_in.each { |row| p row } } # from $stdin
#
# == Data Conversion
#
# === CSV with headers
#
# CSV allows to specify column names of CSV file, whether they are in data, or
# provided separately. If headers are specified, reading methods return an instance
# of CSV::Table, consisting of CSV::Row.
#
# # Headers are part of data
# data = CSV.parse(<<~ROWS, headers: true)
# Name,Department,Salary
# Bob,Engineering,1000
# Jane,Sales,2000
# John,Management,5000
# ROWS
#
# data.class #=> CSV::Table
# data.first #=> #<CSV::Row "Name":"Bob" "Department":"Engineering" "Salary":"1000">
# data.first.to_h #=> {"Name"=>"Bob", "Department"=>"Engineering", "Salary"=>"1000"}
#
# # Headers provided by developer
# data = CSV.parse('Bob,Engineering,1000', headers: %i[name department salary])
# data.first #=> #<CSV::Row name:"Bob" department:"Engineering" salary:"1000">
#
# === Typed data reading
#
# CSV allows to provide a set of data _converters_ e.g. transformations to try on input
# data. Converter could be a symbol from CSV::Converters constant's keys, or lambda.
#
# # Without any converters:
# CSV.parse('Bob,2018-03-01,100')
# #=> [["Bob", "2018-03-01", "100"]]
#
# # With built-in converters:
# CSV.parse('Bob,2018-03-01,100', converters: %i[numeric date])
# #=> [["Bob", #<Date: 2018-03-01>, 100]]
#
# # With custom converters:
# CSV.parse('Bob,2018-03-01,100', converters: [->(v) { Time.parse(v) rescue v }])
# #=> [["Bob", 2018-03-01 00:00:00 +0200, "100"]]
#
# == CSV and Character Encodings (M17n or Multilingualization)
#
# This new CSV parser is m17n savvy. The parser works in the Encoding of the IO
# or String object being read from or written to. Your data is never transcoded
# (unless you ask Ruby to transcode it for you) and will literally be parsed in
# the Encoding it is in. Thus CSV will return Arrays or Rows of Strings in the
# Encoding of your data. This is accomplished by transcoding the parser itself
# into your Encoding.
#
# Some transcoding must take place, of course, to accomplish this multiencoding
# support. For example, <tt>:col_sep</tt>, <tt>:row_sep</tt>, and
# <tt>:quote_char</tt> must be transcoded to match your data. Hopefully this
# makes the entire process feel transparent, since CSV's defaults should just
# magically work for your data. However, you can set these values manually in
# the target Encoding to avoid the translation.
#
# It's also important to note that while all of CSV's core parser is now
# Encoding agnostic, some features are not. For example, the built-in
# converters will try to transcode data to UTF-8 before making conversions.
# Again, you can provide custom converters that are aware of your Encodings to
# avoid this translation. It's just too hard for me to support native
# conversions in all of Ruby's Encodings.
#
# Anyway, the practical side of this is simple: make sure IO and String objects
# passed into CSV have the proper Encoding set and everything should just work.
# CSV methods that allow you to open IO objects (CSV::foreach(), CSV::open(),
# CSV::read(), and CSV::readlines()) do allow you to specify the Encoding.
#
# One minor exception comes when generating CSV into a String with an Encoding
# that is not ASCII compatible. There's no existing data for CSV to use to
# prepare itself and thus you will probably need to manually specify the desired
# Encoding for most of those cases. It will try to guess using the fields in a
# row of output though, when using CSV::generate_line() or Array#to_csv().
#
# I try to point out any other Encoding issues in the documentation of methods
# as they come up.
#
# This has been tested to the best of my ability with all non-"dummy" Encodings
# Ruby ships with. However, it is brave new code and may have some bugs.
# Please feel free to {report}[mailto:james@grayproductions.net] any issues you
# find with it.
#
class CSV

# The error thrown when the parser encounters illegal CSV formatting.
 class MalformedCSVError < RuntimeError
 attr_reader :line_number
 alias_method :lineno, :line_number
 def initialize(message, line_number)
 @line_number = line_number
 super("#{message} in line #{line_number}.")
 end
 end

#
 # A FieldInfo Struct contains details about a field's position in the data
 # source it was read from. CSV will pass this Struct to some blocks that make
 # decisions based on field structure. See CSV.convert_fields() for an
 # example.
 #
 # <tt>index</tt>:: The zero-based index of the field in its row.
 # <tt>line</tt>:: The line of the data source this row is from.
 # <tt>header</tt>:: The header for the column, when available.
 #
 FieldInfo = Struct.new(:index, :line, :header)

# A Regexp used to find and convert some common Date formats.
  DateMatcher     = / \A(?: (\w+,?\s+)?\w+\s+\d{1,2},?\s+\d{2,4} |
                            \d{4}-\d{2}-\d{2} )\z /x
  # A Regexp used to find and convert some common DateTime formats.
  DateTimeMatcher =
    / \A(?: (\w+,?\s+)?\w+\s+\d{1,2}\s+\d{1,2}:\d{1,2}:\d{1,2},?\s+\d{2,4} |
            \d{4}-\d{2}-\d{2}\s\d{2}:\d{2}:\d{2} |
            # ISO-8601
            \d{4}-\d{2}-\d{2}
              (?:T\d{2}:\d{2}(?::\d{2}(?:\.\d+)?(?:[+-]\d{2}(?::\d{2})|Z)?)?)?
        )\z /x

# The encoding used by all converters.
  ConverterEncoding = Encoding.find("UTF-8")

#
 # This Hash holds the built-in converters of CSV that can be accessed by name.
 # You can select Converters with CSV.convert() or through the +options+ Hash
 # passed to CSV::new().
 #
 # <tt>:integer</tt>:: Converts any field Integer() accepts.
 # <tt>:float</tt>:: Converts any field Float() accepts.
 # <tt>:numeric</tt>:: A combination of <tt>:integer</tt>
 # and <tt>:float</tt>.
 # <tt>:date</tt>:: Converts any field Date::parse() accepts.
 # <tt>:date_time</tt>:: Converts any field DateTime::parse() accepts.
 # <tt>:all</tt>:: All built-in converters. A combination of
 # <tt>:date_time</tt> and <tt>:numeric</tt>.
 #
 # All built-in converters transcode field data to UTF-8 before attempting a
 # conversion. If your data cannot be transcoded to UTF-8 the conversion will
 # fail and the field will remain unchanged.
 #
 # This Hash is intentionally left unfrozen and users should feel free to add
 # values to it that can be accessed by all CSV objects.
 #
 # To add a combo field, the value should be an Array of names. Combo fields
 # can be nested with other combo fields.
 #
 Converters = {
 integer: lambda { |f|
 Integer(f.encode(ConverterEncoding)) rescue f
 },
 float: lambda { |f|
 Float(f.encode(ConverterEncoding)) rescue f
 },
 numeric: [:integer, :float],
 date: lambda { |f|
 begin
 e = f.encode(ConverterEncoding)
 e.match?(DateMatcher) ? Date.parse(e) : f
 rescue # encoding conversion or date parse errors
 f
 end
 },
 date_time: lambda { |f|
 begin
 e = f.encode(ConverterEncoding)
 e.match?(DateTimeMatcher) ? DateTime.parse(e) : f
 rescue # encoding conversion or date parse errors
 f
 end
 },
 all: [:date_time, :numeric],
 }

#
 # This Hash holds the built-in header converters of CSV that can be accessed
 # by name. You can select HeaderConverters with CSV.header_convert() or
 # through the +options+ Hash passed to CSV::new().
 #
 # <tt>:downcase</tt>:: Calls downcase() on the header String.
 # <tt>:symbol</tt>:: Leading/trailing spaces are dropped, string is
 # downcased, remaining spaces are replaced with
 # underscores, non-word characters are dropped,
 # and finally to_sym() is called.
 #
 # All built-in header converters transcode header data to UTF-8 before
 # attempting a conversion. If your data cannot be transcoded to UTF-8 the
 # conversion will fail and the header will remain unchanged.
 #
 # This Hash is intentionally left unfrozen and users should feel free to add
 # values to it that can be accessed by all CSV objects.
 #
 # To add a combo field, the value should be an Array of names. Combo fields
 # can be nested with other combo fields.
 #
 HeaderConverters = {
 downcase: lambda { |h| h.encode(ConverterEncoding).downcase },
 symbol: lambda { |h|
 h.encode(ConverterEncoding).downcase.gsub(/[^\s\w]+/, "").strip.
 gsub(/\s+/, "_").to_sym
 }
 }

#
 # The options used when no overrides are given by calling code. They are:
 #
 # <tt>:col_sep</tt>:: <tt>","</tt>
 # <tt>:row_sep</tt>:: <tt>:auto</tt>
 # <tt>:quote_char</tt>:: <tt>'"'</tt>
 # <tt>:field_size_limit</tt>:: +nil+
 # <tt>:converters</tt>:: +nil+
 # <tt>:unconverted_fields</tt>:: +nil+
 # <tt>:headers</tt>:: +false+
 # <tt>:return_headers</tt>:: +false+
 # <tt>:header_converters</tt>:: +nil+
 # <tt>:skip_blanks</tt>:: +false+
 # <tt>:force_quotes</tt>:: +false+
 # <tt>:skip_lines</tt>:: +nil+
 # <tt>:liberal_parsing</tt>:: +false+
 # <tt>:quote_empty</tt>:: +true+
 #
 DEFAULT_OPTIONS = {
 col_sep: ",",
 row_sep: :auto,
 quote_char: '"',
 field_size_limit: nil,
 converters: nil,
 unconverted_fields: nil,
 headers: false,
 return_headers: false,
 header_converters: nil,
 skip_blanks: false,
 force_quotes: false,
 skip_lines: nil,
 liberal_parsing: false,
 quote_empty: true,
 }.freeze

class << self
 #
 # This method will return a CSV instance, just like CSV::new(), but the
 # instance will be cached and returned for all future calls to this method for
 # the same +data+ object (tested by Object#object_id()) with the same
 # +options+.
 #
 # If a block is given, the instance is passed to the block and the return
 # value becomes the return value of the block.
 #
 def instance(data = $stdout, **options)
 # create a _signature_ for this method call, data object and options
 sig = [data.object_id] +
 options.values_at(*DEFAULT_OPTIONS.keys.sort_by { |sym| sym.to_s })

# fetch or create the instance for this signature
      @@instances ||= Hash.new
      instance = (@@instances[sig] ||= new(data, **options))

if block_given?
        yield instance  # run block, if given, returning result
      else
        instance        # or return the instance
      end
    end

#
 # :call-seq:
 # filter( **options ) { |row| ... }
 # filter( input, **options ) { |row| ... }
 # filter( input, output, **options ) { |row| ... }
 #
 # This method is a convenience for building Unix-like filters for CSV data.
 # Each row is yielded to the provided block which can alter it as needed.
 # After the block returns, the row is appended to +output+ altered or not.
 #
 # The +input+ and +output+ arguments can be anything CSV::new() accepts
 # (generally String or IO objects). If not given, they default to
 # <tt>ARGF</tt> and <tt>$stdout</tt>.
 #
 # The +options+ parameter is also filtered down to CSV::new() after some
 # clever key parsing. Any key beginning with <tt>:in_</tt> or
 # <tt>:input_</tt> will have that leading identifier stripped and will only
 # be used in the +options+ Hash for the +input+ object. Keys starting with
 # <tt>:out_</tt> or <tt>:output_</tt> affect only +output+. All other keys
 # are assigned to both objects.
 #
 # The <tt>:output_row_sep</tt> +option+ defaults to
 # <tt>$INPUT_RECORD_SEPARATOR</tt> (<tt>$/</tt>).
 #
 def filter(input=nil, output=nil, **options)
 # parse options for input, output, or both
 in_options, out_options = Hash.new, {row_sep: $INPUT_RECORD_SEPARATOR}
 options.each do |key, value|
 case key.to_s
 when /\Ain(?:put)?_(.+)\Z/
 in_options[$1.to_sym] = value
 when /\Aout(?:put)?_(.+)\Z/
 out_options[$1.to_sym] = value
 else
 in_options[key] = value
 out_options[key] = value
 end
 end
 # build input and output wrappers
 input = new(input || ARGF, **in_options)
 output = new(output || $stdout, **out_options)

# read, yield, write
 input.each do |row|
 yield row
 output << row
 end
 end

#
 # This method is intended as the primary interface for reading CSV files. You
 # pass a +path+ and any +options+ you wish to set for the read. Each row of
 # file will be passed to the provided +block+ in turn.
 #
 # The +options+ parameter can be anything CSV::new() understands. This method
 # also understands an additional <tt>:encoding</tt> parameter that you can use
 # to specify the Encoding of the data in the file to be read. You must provide
 # this unless your data is in Encoding::default_external(). CSV will use this
 # to determine how to parse the data. You may provide a second Encoding to
 # have the data transcoded as it is read. For example,
 # <tt>encoding: "UTF-32BE:UTF-8"</tt> would read UTF-32BE data from the file
 # but transcode it to UTF-8 before CSV parses it.
 #
 def foreach(path, mode="r", **options, &block)
 return to_enum(__method__, path, mode, **options) unless block_given?
 open(path, mode, **options) do |csv|
 csv.each(&block)
 end
 end

#
 # :call-seq:
 # generate( str, **options ) { |csv| ... }
 # generate( **options ) { |csv| ... }
 #
 # This method wraps a String you provide, or an empty default String, in a
 # CSV object which is passed to the provided block. You can use the block to
 # append CSV rows to the String and when the block exits, the final String
 # will be returned.
 #
 # Note that a passed String *is* modified by this method. Call dup() before
 # passing if you need a new String.
 #
 # The +options+ parameter can be anything CSV::new() understands. This method
 # understands an additional <tt>:encoding</tt> parameter when not passed a
 # String to set the base Encoding for the output. CSV needs this hint if you
 # plan to output non-ASCII compatible data.
 #
 def generate(str=nil, **options)
 # add a default empty String, if none was given
 if str
 str = StringIO.new(str)
 str.seek(0, IO::SEEK_END)
 else
 encoding = options[:encoding]
 str = +""
 str.force_encoding(encoding) if encoding
 end
 csv = new(str, **options) # wrap
 yield csv # yield for appending
 csv.string # return final String
 end

#
 # This method is a shortcut for converting a single row (Array) into a CSV
 # String.
 #
 # The +options+ parameter can be anything CSV::new() understands. This method
 # understands an additional <tt>:encoding</tt> parameter to set the base
 # Encoding for the output. This method will try to guess your Encoding from
 # the first non-+nil+ field in +row+, if possible, but you may need to use
 # this parameter as a backup plan.
 #
 # The <tt>:row_sep</tt> +option+ defaults to <tt>$INPUT_RECORD_SEPARATOR</tt>
 # (<tt>$/</tt>) when calling this method.
 #
 def generate_line(row, **options)
 options = {row_sep: $INPUT_RECORD_SEPARATOR}.merge(options)
 str = +""
 if options[:encoding]
 str.force_encoding(options[:encoding])
 elsif field = row.find {|f| f.is_a?(String)}
 str.force_encoding(field.encoding)
 end
 (new(str, **options) << row).string
 end

#
 # :call-seq:
 # open( filename, mode = "rb", **options ) { |faster_csv| ... }
 # open( filename, **options ) { |faster_csv| ... }
 # open( filename, mode = "rb", **options )
 # open( filename, **options )
 #
 # This method opens an IO object, and wraps that with CSV. This is intended
 # as the primary interface for writing a CSV file.
 #
 # You must pass a +filename+ and may optionally add a +mode+ for Ruby's
 # open(). You may also pass an optional Hash containing any +options+
 # CSV::new() understands as the final argument.
 #
 # This method works like Ruby's open() call, in that it will pass a CSV object
 # to a provided block and close it when the block terminates, or it will
 # return the CSV object when no block is provided. (*Note*: This is different
 # from the Ruby 1.8 CSV library which passed rows to the block. Use
 # CSV::foreach() for that behavior.)
 #
 # You must provide a +mode+ with an embedded Encoding designator unless your
 # data is in Encoding::default_external(). CSV will check the Encoding of the
 # underlying IO object (set by the +mode+ you pass) to determine how to parse
 # the data. You may provide a second Encoding to have the data transcoded as
 # it is read just as you can with a normal call to IO::open(). For example,
 # <tt>"rb:UTF-32BE:UTF-8"</tt> would read UTF-32BE data from the file but
 # transcode it to UTF-8 before CSV parses it.
 #
 # An opened CSV object will delegate to many IO methods for convenience. You
 # may call:
 #
 # * binmode()
 # * binmode?()
 # * close()
 # * close_read()
 # * close_write()
 # * closed?()
 # * eof()
 # * eof?()
 # * external_encoding()
 # * fcntl()
 # * fileno()
 # * flock()
 # * flush()
 # * fsync()
 # * internal_encoding()
 # * ioctl()
 # * isatty()
 # * path()
 # * pid()
 # * pos()
 # * pos=()
 # * reopen()
 # * seek()
 # * stat()
 # * sync()
 # * sync=()
 # * tell()
 # * to_i()
 # * to_io()
 # * truncate()
 # * tty?()
 #
 def open(filename, mode="r", **options)
 # wrap a File opened with the remaining +args+ with no newline
 # decorator
 file_opts = {universal_newline: false}.merge(options)

begin
        f = File.open(filename, mode, **file_opts)
      rescue ArgumentError => e
        raise unless /needs binmode/.match?(e.message) and mode == "r"
        mode = "rb"
        file_opts = {encoding: Encoding.default_external}.merge(file_opts)
        retry
      end
      begin
        csv = new(f, **options)
      rescue Exception
        f.close
        raise
      end

# handle blocks like Ruby's open(), not like the CSV library
      if block_given?
        begin
          yield csv
        ensure
          csv.close
        end
      else
        csv
      end
    end

#
    # :call-seq:
    #   parse( str, **options ) { |row| ... }
    #   parse( str, **options )
    #
    # This method can be used to easily parse CSV out of a String. You may either
    # provide a +block+ which will be called with each row of the String in turn,
    # or just use the returned Array of Arrays (when no +block+ is given).
    #
    # You pass your +str+ to read from, and an optional +options+ containing
    # anything CSV::new() understands.
    #
    def parse(str, **options, &block)
      csv = new(str, **options)

return csv.each(&block) if block_given?

# slurp contents, if no block is given
      begin
        csv.read
      ensure
        csv.close
      end
    end

#
    # This method is a shortcut for converting a single line of a CSV String into
    # an Array. Note that if +line+ contains multiple rows, anything beyond the
    # first row is ignored.
    #
    # The +options+ parameter can be anything CSV::new() understands.
    #
    def parse_line(line, **options)
      new(line, **options).shift
    end

#
 # Use to slurp a CSV file into an Array of Arrays. Pass the +path+ to the
 # file and any +options+ CSV::new() understands. This method also understands
 # an additional <tt>:encoding</tt> parameter that you can use to specify the
 # Encoding of the data in the file to be read. You must provide this unless
 # your data is in Encoding::default_external(). CSV will use this to determine
 # how to parse the data. You may provide a second Encoding to have the data
 # transcoded as it is read. For example,
 # <tt>encoding: "UTF-32BE:UTF-8"</tt> would read UTF-32BE data from the file
 # but transcode it to UTF-8 before CSV parses it.
 #
 def read(path, **options)
 open(path, **options) { |csv| csv.read }
 end

# Alias for CSV::read().
    def readlines(path, **options)
      read(path, **options)
    end

#
    # A shortcut for:
    #
    #   CSV.read( path, { headers:           true,
    #                     converters:        :numeric,
    #                     header_converters: :symbol }.merge(options) )
    #
    def table(path, **options)
      default_options = {
        headers:           true,
        converters:        :numeric,
        header_converters: :symbol,
      }
      options = default_options.merge(options)
      read(path, **options)
    end
  end

#
 # This constructor will wrap either a String or IO object passed in +data+ for
 # reading and/or writing. In addition to the CSV instance methods, several IO
 # methods are delegated. (See CSV::open() for a complete list.) If you pass
 # a String for +data+, you can later retrieve it (after writing to it, for
 # example) with CSV.string().
 #
 # Note that a wrapped String will be positioned at the beginning (for
 # reading). If you want it at the end (for writing), use CSV::generate().
 # If you want any other positioning, pass a preset StringIO object instead.
 #
 # You may set any reading and/or writing preferences in the +options+ Hash.
 # Available options are:
 #
 # <tt>:col_sep</tt>:: The String placed between each field.
 # This String will be transcoded into
 # the data's Encoding before parsing.
 # <tt>:row_sep</tt>:: The String appended to the end of each
 # row. This can be set to the special
 # <tt>:auto</tt> setting, which requests
 # that CSV automatically discover this
 # from the data. Auto-discovery reads
 # ahead in the data looking for the next
 # <tt>"\r\n"</tt>, <tt>"\n"</tt>, or
 # <tt>"\r"</tt> sequence. A sequence
 # will be selected even if it occurs in
 # a quoted field, assuming that you
 # would have the same line endings
 # there. If none of those sequences is
 # found, +data+ is <tt>ARGF</tt>,
 # <tt>STDIN</tt>, <tt>STDOUT</tt>, or
 # <tt>STDERR</tt>, or the stream is only
 # available for output, the default
 # <tt>$INPUT_RECORD_SEPARATOR</tt>
 # (<tt>$/</tt>) is used. Obviously,
 # discovery takes a little time. Set
 # manually if speed is important. Also
 # note that IO objects should be opened
 # in binary mode on Windows if this
 # feature will be used as the
 # line-ending translation can cause
 # problems with resetting the document
 # position to where it was before the
 # read ahead. This String will be
 # transcoded into the data's Encoding
 # before parsing.
 # <tt>:quote_char</tt>:: The character used to quote fields.
 # This has to be a single character
 # String. This is useful for
 # application that incorrectly use
 # <tt>'</tt> as the quote character
 # instead of the correct <tt>"</tt>.
 # CSV will always consider a double
 # sequence of this character to be an
 # escaped quote. This String will be
 # transcoded into the data's Encoding
 # before parsing.
 # <tt>:field_size_limit</tt>:: This is a maximum size CSV will read
 # ahead looking for the closing quote
 # for a field. (In truth, it reads to
 # the first line ending beyond this
 # size.) If a quote cannot be found
 # within the limit CSV will raise a
 # MalformedCSVError, assuming the data
 # is faulty. You can use this limit to
 # prevent what are effectively DoS
 # attacks on the parser. However, this
 # limit can cause a legitimate parse to
 # fail and thus is set to +nil+, or off,
 # by default.
 # <tt>:converters</tt>:: An Array of names from the Converters
 # Hash and/or lambdas that handle custom
 # conversion. A single converter
 # doesn't have to be in an Array. All
 # built-in converters try to transcode
 # fields to UTF-8 before converting.
 # The conversion will fail if the data
 # cannot be transcoded, leaving the
 # field unchanged.
 # <tt>:unconverted_fields</tt>:: If set to +true+, an
 # unconverted_fields() method will be
 # added to all returned rows (Array or
 # CSV::Row) that will return the fields
 # as they were before conversion. Note
 # that <tt>:headers</tt> supplied by
 # Array or String were not fields of the
 # document and thus will have an empty
 # Array attached.
 # <tt>:headers</tt>:: If set to <tt>:first_row</tt> or
 # +true+, the initial row of the CSV
 # file will be treated as a row of
 # headers. If set to an Array, the
 # contents will be used as the headers.
 # If set to a String, the String is run
 # through a call of CSV::parse_line()
 # with the same <tt>:col_sep</tt>,
 # <tt>:row_sep</tt>, and
 # <tt>:quote_char</tt> as this instance
 # to produce an Array of headers. This
 # setting causes CSV#shift() to return
 # rows as CSV::Row objects instead of
 # Arrays and CSV#read() to return
 # CSV::Table objects instead of an Array
 # of Arrays.
 # <tt>:return_headers</tt>:: When +false+, header rows are silently
 # swallowed. If set to +true+, header
 # rows are returned in a CSV::Row object
 # with identical headers and
 # fields (save that the fields do not go
 # through the converters).
 # <tt>:write_headers</tt>:: When +true+ and <tt>:headers</tt> is
 # set, a header row will be added to the
 # output.
 # <tt>:header_converters</tt>:: Identical in functionality to
 # <tt>:converters</tt> save that the
 # conversions are only made to header
 # rows. All built-in converters try to
 # transcode headers to UTF-8 before
 # converting. The conversion will fail
 # if the data cannot be transcoded,
 # leaving the header unchanged.
 # <tt>:skip_blanks</tt>:: When setting a +true+ value, CSV will
 # skip over any empty rows. Note that
 # this setting will not skip rows that
 # contain column separators, even if
 # the rows contain no actual data. If
 # you want to skip rows that contain
 # separators but no content, consider
 # using <tt>:skip_lines</tt>, or
 # inspecting fields.compact.empty? on
 # each row.
 # <tt>:force_quotes</tt>:: When setting a +true+ value, CSV will
 # quote all CSV fields it creates.
 # <tt>:skip_lines</tt>:: When setting an object responding to
 # <tt>match</tt>, every line matching
 # it is considered a comment and ignored
 # during parsing. When set to a String,
 # it is first converted to a Regexp.
 # When set to +nil+ no line is considered
 # a comment. If the passed object does
 # not respond to <tt>match</tt>,
 # <tt>ArgumentError</tt> is thrown.
 # <tt>:liberal_parsing</tt>:: When setting a +true+ value, CSV will
 # attempt to parse input not conformant
 # with RFC 4180, such as double quotes
 # in unquoted fields.
 # <tt>:nil_value</tt>:: When set an object, any values of an
 # empty field is replaced by the set
 # object, not nil.
 # <tt>:empty_value</tt>:: When setting an object, any values of a
 # blank string field is replaced by
 # the set object.
 # <tt>:quote_empty</tt>:: When setting a +true+ value, CSV will
 # quote empty values with double quotes.
 # When +false+, CSV will emit an
 # empty string for an empty field value.
 # <tt>:write_converters</tt>:: Converts values on each line with the
 # specified <tt>Proc</tt> object(s),
 # which receive a <tt>String</tt> value
 # and return a <tt>String</tt> or +nil+
 # value.
 # When an array is specified, each
 # converter will be applied in order.
 # <tt>:write_nil_value</tt>:: When a <tt>String</tt> value, +nil+
 # value(s) on each line will be replaced
 # with the specified value.
 # <tt>:write_empty_value</tt>:: When a <tt>String</tt> or +nil+ value,
 # empty value(s) on each line will be
 # replaced with the specified value.
 # <tt>:strip</tt>:: When setting a +true+ value, CSV will
 # strip "\t\r\n\f\v" around the values.
 # If you specify a string instead of
 # +true+, CSV will strip string. The
 # length of the string must be 1.
 #
 # See CSV::DEFAULT_OPTIONS for the default settings.
 #
 # Options cannot be overridden in the instance methods for performance reasons,
 # so be sure to set what you want here.
 #
 def initialize(data,
 col_sep: ",",
 row_sep: :auto,
 quote_char: '"',
 field_size_limit: nil,
 converters: nil,
 unconverted_fields: nil,
 headers: false,
 return_headers: false,
 write_headers: nil,
 header_converters: nil,
 skip_blanks: false,
 force_quotes: false,
 skip_lines: nil,
 liberal_parsing: false,
 internal_encoding: nil,
 external_encoding: nil,
 encoding: nil,
 nil_value: nil,
 empty_value: "",
 quote_empty: true,
 write_converters: nil,
 write_nil_value: nil,
 write_empty_value: "",
 strip: false)
 raise ArgumentError.new("Cannot parse nil as CSV") if data.nil?

if data.is_a?(String)
      @io = StringIO.new(data)
      @io.set_encoding(encoding || data.encoding)
    else
      @io = data
    end
    @encoding = determine_encoding(encoding, internal_encoding)

@base_fields_converter_options = {
      nil_value: nil_value,
      empty_value: empty_value,
    }
    @write_fields_converter_options = {
      nil_value: write_nil_value,
      empty_value: write_empty_value,
    }
    @initial_converters = converters
    @initial_header_converters = header_converters
    @initial_write_converters = write_converters

@parser_options = {
      column_separator: col_sep,
      row_separator: row_sep,
      quote_character: quote_char,
      field_size_limit: field_size_limit,
      unconverted_fields: unconverted_fields,
      headers: headers,
      return_headers: return_headers,
      skip_blanks: skip_blanks,
      skip_lines: skip_lines,
      liberal_parsing: liberal_parsing,
      encoding: @encoding,
      nil_value: nil_value,
      empty_value: empty_value,
      strip: strip,
    }
    @parser = nil
    @parser_enumerator = nil
    @eof_error = nil

@writer_options = {
      encoding: @encoding,
      force_encoding: (not encoding.nil?),
      force_quotes: force_quotes,
      headers: headers,
      write_headers: write_headers,
      column_separator: col_sep,
      row_separator: row_sep,
      quote_character: quote_char,
      quote_empty: quote_empty,
    }

@writer = nil
    writer if @writer_options[:write_headers]
  end

#
 # The encoded <tt>:col_sep</tt> used in parsing and writing.
 # See CSV::new for details.
 #
 def col_sep
 parser.column_separator
 end

#
 # The encoded <tt>:row_sep</tt> used in parsing and writing.
 # See CSV::new for details.
 #
 def row_sep
 parser.row_separator
 end

#
 # The encoded <tt>:quote_char</tt> used in parsing and writing.
 # See CSV::new for details.
 #
 def quote_char
 parser.quote_character
 end

#
  # The limit for field size, if any.
  # See CSV::new for details.
  #
  def field_size_limit
    parser.field_size_limit
  end

#
  # The regex marking a line as a comment.
  # See CSV::new for details.
  #
  def skip_lines
    parser.skip_lines
  end

#
  # Returns the current list of converters in effect. See CSV::new for details.
  # Built-in converters will be returned by name, while others will be returned
  # as is.
  #
  def converters
    parser_fields_converter.map do |converter|
      name = Converters.rassoc(converter)
      name ? name.first : converter
    end
  end

#
  # Returns +true+ if unconverted_fields() to parsed results.
  # See CSV::new for details.
  #
  def unconverted_fields?
    parser.unconverted_fields?
  end

#
  # Returns +nil+ if headers will not be used, +true+ if they will but have not
  # yet been read, or the actual headers after they have been read.
  # See CSV::new for details.
  #
  def headers
    if @writer
      @writer.headers
    else
      parsed_headers = parser.headers
      return parsed_headers if parsed_headers
      raw_headers = @parser_options[:headers]
      raw_headers = nil if raw_headers == false
      raw_headers
    end
  end
  #
  # Returns +true+ if headers will be returned as a row of results.
  # See CSV::new for details.
  #
  def return_headers?
    parser.return_headers?
  end

#
  # Returns +true+ if headers are written in output.
  # See CSV::new for details.
  #
  def write_headers?
    @writer_options[:write_headers]
  end

#
  # Returns the current list of converters in effect for headers. See CSV::new
  # for details. Built-in converters will be returned by name, while others
  # will be returned as is.
  #
  def header_converters
    header_fields_converter.map do |converter|
      name = HeaderConverters.rassoc(converter)
      name ? name.first : converter
    end
  end

#
  # Returns +true+ blank lines are skipped by the parser. See CSV::new
  # for details.
  #
  def skip_blanks?
    parser.skip_blanks?
  end

# Returns +true+ if all output fields are quoted. See CSV::new for details.
  def force_quotes?
    @writer_options[:force_quotes]
  end

# Returns +true+ if illegal input is handled. See CSV::new for details.
  def liberal_parsing?
    parser.liberal_parsing?
  end

#
  # The Encoding CSV is parsing or writing in.  This will be the Encoding you
  # receive parsed data in and/or the Encoding data will be written in.
  #
  attr_reader :encoding

#
  # The line number of the last row read from this file. Fields with nested
  # line-end characters will not affect this count.
  #
  def lineno
    if @writer
      @writer.lineno
    else
      parser.lineno
    end
  end

#
  # The last row read from this file.
  #
  def line
    parser.line
  end

### IO and StringIO Delegation ###

extend Forwardable
  def_delegators :@io, :binmode, :close, :close_read, :close_write,
                       :closed?, :external_encoding, :fcntl,
                       :fileno, :flush, :fsync, :internal_encoding,
                       :isatty, :pid, :pos, :pos=, :reopen,
                       :seek, :string, :sync, :sync=, :tell,
                       :truncate, :tty?

def binmode?
    if @io.respond_to?(:binmode?)
      @io.binmode?
    else
      false
    end
  end

def flock(*args)
    raise NotImplementedError unless @io.respond_to?(:flock)
    @io.flock(*args)
  end

def ioctl(*args)
    raise NotImplementedError unless @io.respond_to?(:ioctl)
    @io.ioctl(*args)
  end

def path
    @io.path if @io.respond_to?(:path)
  end

def stat(*args)
    raise NotImplementedError unless @io.respond_to?(:stat)
    @io.stat(*args)
  end

def to_i
    raise NotImplementedError unless @io.respond_to?(:to_i)
    @io.to_i
  end

def to_io
    @io.respond_to?(:to_io) ? @io.to_io : @io
  end

def eof?
    return false if @eof_error
    begin
      parser_enumerator.peek
      false
    rescue MalformedCSVError => error
      @eof_error = error
      false
    rescue StopIteration
      true
    end
  end
  alias_method :eof, :eof?

# Rewinds the underlying IO object and resets CSV's lineno() counter.
  def rewind
    @parser = nil
    @parser_enumerator = nil
    @eof_error = nil
    @writer.rewind if @writer
    @io.rewind
  end

### End Delegation ###

#
 # The primary write method for wrapped Strings and IOs, +row+ (an Array or
 # CSV::Row) is converted to CSV and appended to the data source. When a
 # CSV::Row is passed, only the row's fields() are appended to the output.
 #
 # The data source must be open for writing.
 #
 def <<(row)
 writer << row
 self
 end
 alias_method :add_row, :<<
 alias_method :puts, :<<

#
  # :call-seq:
  #   convert( name )
  #   convert { |field| ... }
  #   convert { |field, field_info| ... }
  #
  # You can use this method to install a CSV::Converters built-in, or provide a
  # block that handles a custom conversion.
  #
  # If you provide a block that takes one argument, it will be passed the field
  # and is expected to return the converted value or the field itself. If your
  # block takes two arguments, it will also be passed a CSV::FieldInfo Struct,
  # containing details about the field. Again, the block should return a
  # converted field or the field itself.
  #
  def convert(name = nil, &converter)
    parser_fields_converter.add_converter(name, &converter)
  end

#
  # :call-seq:
  #   header_convert( name )
  #   header_convert { |field| ... }
  #   header_convert { |field, field_info| ... }
  #
  # Identical to CSV#convert(), but for header rows.
  #
  # Note that this method must be called before header rows are read to have any
  # effect.
  #
  def header_convert(name = nil, &converter)
    header_fields_converter.add_converter(name, &converter)
  end

include Enumerable

#
  # Yields each row of the data source in turn.
  #
  # Support for Enumerable.
  #
  # The data source must be open for reading.
  #
  def each(&block)
    parser_enumerator.each(&block)
  end

#
  # Slurps the remaining rows and returns an Array of Arrays.
  #
  # The data source must be open for reading.
  #
  def read
    rows = to_a
    if parser.use_headers?
      Table.new(rows, headers: parser.headers)
    else
      rows
    end
  end
  alias_method :readlines, :read

# Returns +true+ if the next row read will be a header row.
  def header_row?
    parser.header_row?
  end

#
  # The primary read method for wrapped Strings and IOs, a single row is pulled
  # from the data source, parsed and returned as an Array of fields (if header
  # rows are not used) or a CSV::Row (when header rows are used).
  #
  # The data source must be open for reading.
  #
  def shift
    if @eof_error
      eof_error, @eof_error = @eof_error, nil
      raise eof_error
    end
    begin
      parser_enumerator.next
    rescue StopIteration
      nil
    end
  end
  alias_method :gets,     :shift
  alias_method :readline, :shift

#
 # Returns a simplified description of the key CSV attributes in an
 # ASCII compatible String.
 #
 def inspect
 str = ["#<", self.class.to_s, " io_type:"]
 # show type of wrapped IO
 if @io == $stdout then str << "$stdout"
 elsif @io == $stdin then str << "$stdin"
 elsif @io == $stderr then str << "$stderr"
 else str << @io.class.to_s
 end
 # show IO.path(), if available
 if @io.respond_to?(:path) and (p = @io.path)
 str << " io_path:" << p.inspect
 end
 # show encoding
 str << " encoding:" << @encoding.name
 # show other attributes
 ["lineno", "col_sep", "row_sep", "quote_char"].each do |attr_name|
 if a = __send__(attr_name)
 str << " " << attr_name << ":" << a.inspect
 end
 end
 ["skip_blanks", "liberal_parsing"].each do |attr_name|
 if a = __send__("#{attr_name}?")
 str << " " << attr_name << ":" << a.inspect
 end
 end
 _headers = headers
 str << " headers:" << _headers.inspect if _headers
 str << ">"
 begin
 str.join('')
 rescue # any encoding error
 str.map do |s|
 e = Encoding::Converter.asciicompat_encoding(s.encoding)
 e ? s.encode(e) : s.force_encoding("ASCII-8BIT")
 end.join('')
 end
 end

private

def determine_encoding(encoding, internal_encoding)
    # honor the IO encoding if we can, otherwise default to ASCII-8BIT
    io_encoding = raw_encoding
    return io_encoding if io_encoding

return Encoding.find(internal_encoding) if internal_encoding

if encoding
      encoding, = encoding.split(":", 2) if encoding.is_a?(String)
      return Encoding.find(encoding)
    end

Encoding.default_internal || Encoding.default_external
  end

def normalize_converters(converters)
    converters ||= []
    unless converters.is_a?(Array)
      converters = [converters]
    end
    converters.collect do |converter|
      case converter
      when Proc # custom code block
        [nil, converter]
      else # by name
        [converter, nil]
      end
    end
  end

#
 # Processes +fields+ with <tt>@converters</tt>, or <tt>@header_converters</tt>
 # if +headers+ is passed as +true+, returning the converted field set. Any
 # converter that changes the field into something other than a String halts
 # the pipeline of conversion for that field. This is primarily an efficiency
 # shortcut.
 #
 def convert_fields(fields, headers = false)
 if headers
 header_fields_converter.convert(fields, nil, 0)
 else
 parser_fields_converter.convert(fields, @headers, lineno)
 end
 end

#
  # Returns the encoding of the internal IO object.
  #
  def raw_encoding
    if @io.respond_to? :internal_encoding
      @io.internal_encoding || @io.external_encoding
    elsif @io.respond_to? :encoding
      @io.encoding
    else
      nil
    end
  end

def parser_fields_converter
    @parser_fields_converter ||= build_parser_fields_converter
  end

def build_parser_fields_converter
    specific_options = {
      builtin_converters: Converters,
    }
    options = @base_fields_converter_options.merge(specific_options)
    build_fields_converter(@initial_converters, options)
  end

def header_fields_converter
    @header_fields_converter ||= build_header_fields_converter
  end

def build_header_fields_converter
    specific_options = {
      builtin_converters: HeaderConverters,
      accept_nil: true,
    }
    options = @base_fields_converter_options.merge(specific_options)
    build_fields_converter(@initial_header_converters, options)
  end

def writer_fields_converter
    @writer_fields_converter ||= build_writer_fields_converter
  end

def build_writer_fields_converter
    build_fields_converter(@initial_write_converters,
                           @write_fields_converter_options)
  end

def build_fields_converter(initial_converters, options)
    fields_converter = FieldsConverter.new(options)
    normalize_converters(initial_converters).each do |name, converter|
      fields_converter.add_converter(name, &converter)
    end
    fields_converter
  end

def parser
    @parser ||= Parser.new(@io, parser_options)
  end

def parser_options
    @parser_options.merge(header_fields_converter: header_fields_converter,
                          fields_converter: parser_fields_converter)
  end

def parser_enumerator
    @parser_enumerator ||= parser.parse
  end

def writer
    @writer ||= Writer.new(@io, writer_options)
  end

def writer_options
    @writer_options.merge(header_fields_converter: header_fields_converter,
                          fields_converter: writer_fields_converter)
  end
end

# Passes +args+ to CSV::instance.
#
#   CSV("CSV,data").read
#     #=> [["CSV", "data"]]
#
# If a block is given, the instance is passed the block and the return value
# becomes the return value of the block.
#
#   CSV("CSV,data") { |c|
#     c.read.any? { |a| a.include?("data") }
#   } #=> true
#
#   CSV("CSV,data") { |c|
#     c.read.any? { |a| a.include?("zombies") }
#   } #=> false
#
def CSV(*args, &block)
  CSV.instance(*args, &block)
end

require_relative "csv/version"
require_relative "csv/core_ext/array"
require_relative "csv/core_ext/string"