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Feature #1981 » csv.rb

Patched csv.rb - ender672 (Timothy Elliott), 08/23/2009 04:44 AM

 
# encoding: US-ASCII
# = csv.rb -- CSV Reading and Writing
#
# Created by James Edward Gray II on 2005-10-31.
# Copyright 2005 James Edward Gray II. You can redistribute or modify this code
# under the terms of Ruby's license.
#
# 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.
#
# == What's 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 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 eats 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"

#
# 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.
#
# == Reading
#
# === From a File
#
# ==== A Line at a Time
#
# CSV.foreach("path/to/file.csv") do |row|
# # use row here...
# end
#
# ==== All at Once
#
# arr_of_arrs = CSV.read("path/to/file.csv")
#
# === From a String
#
# ==== A Line at a Time
#
# CSV.parse("CSV,data,String") do |row|
# # use row here...
# end
#
# ==== All at Once
#
# arr_of_arrs = CSV.parse("CSV,data,String")
#
# == 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
#
# == Convert a Single Line
#
# csv_string = ["CSV", "data"].to_csv # to CSV
# csv_array = "CSV,String".parse_csv # from CSV
#
# == Shortcut Interface
#
# 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 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 you 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 version of the installed library.
VERSION = "2.4.5".freeze

#
# A CSV::Row is part Array and part Hash. It retains an order for the fields
# and allows duplicates just as an Array would, but also allows you to access
# fields by name just as you could if they were in a Hash.
#
# All rows returned by CSV will be constructed from this class, if header row
# processing is activated.
#
class Row
#
# Construct a new CSV::Row from +headers+ and +fields+, which are expected
# to be Arrays. If one Array is shorter than the other, it will be padded
# with +nil+ objects.
#
# The optional +header_row+ parameter can be set to +true+ to indicate, via
# CSV::Row.header_row?() and CSV::Row.field_row?(), that this is a header
# row. Otherwise, the row is assumes to be a field row.
#
# A CSV::Row object supports the following Array methods through delegation:
#
# * empty?()
# * length()
# * size()
#
def initialize(headers, fields, header_row = false)
@header_row = header_row

# handle extra headers or fields
@row = if headers.size > fields.size
headers.zip(fields)
else
fields.zip(headers).map { |pair| pair.reverse }
end
end

# Internal data format used to compare equality.
attr_reader :row
protected :row

### Array Delegation ###

extend Forwardable
def_delegators :@row, :empty?, :length, :size

# Returns +true+ if this is a header row.
def header_row?
@header_row
end

# Returns +true+ if this is a field row.
def field_row?
not header_row?
end

# Returns the headers of this row.
def headers
@row.map { |pair| pair.first }
end

#
# :call-seq:
# field( header )
# field( header, offset )
# field( index )
#
# This method will fetch the field value by +header+ or +index+. If a field
# is not found, +nil+ is returned.
#
# When provided, +offset+ ensures that a header match occurrs on or later
# than the +offset+ index. You can use this to find duplicate headers,
# without resorting to hard-coding exact indices.
#
def field(header_or_index, minimum_index = 0)
# locate the pair
finder = header_or_index.is_a?(Integer) ? :[] : :assoc
pair = @row[minimum_index..-1].send(finder, header_or_index)

# return the field if we have a pair
pair.nil? ? nil : pair.last
end
alias_method :[], :field

#
# :call-seq:
# []=( header, value )
# []=( header, offset, value )
# []=( index, value )
#
# Looks up the field by the semantics described in CSV::Row.field() and
# assigns the +value+.
#
# Assigning past the end of the row with an index will set all pairs between
# to <tt>[nil, nil]</tt>. Assigning to an unused header appends the new
# pair.
#
def []=(*args)
value = args.pop

if args.first.is_a? Integer
if @row[args.first].nil? # extending past the end with index
@row[args.first] = [nil, value]
@row.map! { |pair| pair.nil? ? [nil, nil] : pair }
else # normal index assignment
@row[args.first][1] = value
end
else
index = index(*args)
if index.nil? # appending a field
self << [args.first, value]
else # normal header assignment
@row[index][1] = value
end
end
end

#
# :call-seq:
# <<( field )
# <<( header_and_field_array )
# <<( header_and_field_hash )
#
# If a two-element Array is provided, it is assumed to be a header and field
# and the pair is appended. A Hash works the same way with the key being
# the header and the value being the field. Anything else is assumed to be
# a lone field which is appended with a +nil+ header.
#
# This method returns the row for chaining.
#
def <<(arg)
if arg.is_a?(Array) and arg.size == 2 # appending a header and name
@row << arg
elsif arg.is_a?(Hash) # append header and name pairs
arg.each { |pair| @row << pair }
else # append field value
@row << [nil, arg]
end

self # for chaining
end

#
# A shortcut for appending multiple fields. Equivalent to:
#
# args.each { |arg| csv_row << arg }
#
# This method returns the row for chaining.
#
def push(*args)
args.each { |arg| self << arg }

self # for chaining
end

#
# :call-seq:
# delete( header )
# delete( header, offset )
# delete( index )
#
# Used to remove a pair from the row by +header+ or +index+. The pair is
# located as described in CSV::Row.field(). The deleted pair is returned,
# or +nil+ if a pair could not be found.
#
def delete(header_or_index, minimum_index = 0)
if header_or_index.is_a? Integer # by index
@row.delete_at(header_or_index)
else # by header
@row.delete_at(index(header_or_index, minimum_index))
end
end

#
# The provided +block+ is passed a header and field for each pair in the row
# and expected to return +true+ or +false+, depending on whether the pair
# should be deleted.
#
# This method returns the row for chaining.
#
def delete_if(&block)
@row.delete_if(&block)

self # for chaining
end

#
# This method accepts any number of arguments which can be headers, indices,
# Ranges of either, or two-element Arrays containing a header and offset.
# Each argument will be replaced with a field lookup as described in
# CSV::Row.field().
#
# If called with no arguments, all fields are returned.
#
def fields(*headers_and_or_indices)
if headers_and_or_indices.empty? # return all fields--no arguments
@row.map { |pair| pair.last }
else # or work like values_at()
headers_and_or_indices.inject(Array.new) do |all, h_or_i|
all + if h_or_i.is_a? Range
index_begin = h_or_i.begin.is_a?(Integer) ? h_or_i.begin :
index(h_or_i.begin)
index_end = h_or_i.end.is_a?(Integer) ? h_or_i.end :
index(h_or_i.end)
new_range = h_or_i.exclude_end? ? (index_begin...index_end) :
(index_begin..index_end)
fields.values_at(new_range)
else
[field(*Array(h_or_i))]
end
end
end
end
alias_method :values_at, :fields

#
# :call-seq:
# index( header )
# index( header, offset )
#
# This method will return the index of a field with the provided +header+.
# The +offset+ can be used to locate duplicate header names, as described in
# CSV::Row.field().
#
def index(header, minimum_index = 0)
# find the pair
index = headers[minimum_index..-1].index(header)
# return the index at the right offset, if we found one
index.nil? ? nil : index + minimum_index
end

# Returns +true+ if +name+ is a header for this row, and +false+ otherwise.
def header?(name)
headers.include? name
end
alias_method :include?, :header?

#
# Returns +true+ if +data+ matches a field in this row, and +false+
# otherwise.
#
def field?(data)
fields.include? data
end

include Enumerable

#
# Yields each pair of the row as header and field tuples (much like
# iterating over a Hash).
#
# Support for Enumerable.
#
# This method returns the row for chaining.
#
def each(&block)
@row.each(&block)

self # for chaining
end

#
# Returns +true+ if this row contains the same headers and fields in the
# same order as +other+.
#
def ==(other)
@row == other.row
end

#
# Collapses the row into a simple Hash. Be warning that this discards field
# order and clobbers duplicate fields.
#
def to_hash
# flatten just one level of the internal Array
Hash[*@row.inject(Array.new) { |ary, pair| ary.push(*pair) }]
end

#
# Returns the row as a CSV String. Headers are not used. Equivalent to:
#
# csv_row.fields.to_csv( options )
#
def to_csv(options = Hash.new)
fields.to_csv(options)
end
alias_method :to_s, :to_csv

# A summary of fields, by header, in an ASCII compatible String.
def inspect
str = ["#<", self.class.to_s]
each do |header, field|
str << " " << (header.is_a?(Symbol) ? header.to_s : header.inspect) <<
":" << field.inspect
end
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
end

#
# A CSV::Table is a two-dimensional data structure for representing CSV
# documents. Tables allow you to work with the data by row or column,
# manipulate the data, and even convert the results back to CSV, if needed.
#
# All tables returned by CSV will be constructed from this class, if header
# row processing is activated.
#
class Table
#
# Construct a new CSV::Table from +array_of_rows+, which are expected
# to be CSV::Row objects. All rows are assumed to have the same headers.
#
# A CSV::Table object supports the following Array methods through
# delegation:
#
# * empty?()
# * length()
# * size()
#
def initialize(array_of_rows)
@table = array_of_rows
@mode = :col_or_row
end

# The current access mode for indexing and iteration.
attr_reader :mode

# Internal data format used to compare equality.
attr_reader :table
protected :table

### Array Delegation ###

extend Forwardable
def_delegators :@table, :empty?, :length, :size

#
# Returns a duplicate table object, in column mode. This is handy for
# chaining in a single call without changing the table mode, but be aware
# that this method can consume a fair amount of memory for bigger data sets.
#
# This method returns the duplicate table for chaining. Don't chain
# destructive methods (like []=()) this way though, since you are working
# with a duplicate.
#
def by_col
self.class.new(@table.dup).by_col!
end

#
# Switches the mode of this table to column mode. All calls to indexing and
# iteration methods will work with columns until the mode is changed again.
#
# This method returns the table and is safe to chain.
#
def by_col!
@mode = :col

self
end

#
# Returns a duplicate table object, in mixed mode. This is handy for
# chaining in a single call without changing the table mode, but be aware
# that this method can consume a fair amount of memory for bigger data sets.
#
# This method returns the duplicate table for chaining. Don't chain
# destructive methods (like []=()) this way though, since you are working
# with a duplicate.
#
def by_col_or_row
self.class.new(@table.dup).by_col_or_row!
end

#
# Switches the mode of this table to mixed mode. All calls to indexing and
# iteration methods will use the default intelligent indexing system until
# the mode is changed again. In mixed mode an index is assumed to be a row
# reference while anything else is assumed to be column access by headers.
#
# This method returns the table and is safe to chain.
#
def by_col_or_row!
@mode = :col_or_row

self
end

#
# Returns a duplicate table object, in row mode. This is handy for chaining
# in a single call without changing the table mode, but be aware that this
# method can consume a fair amount of memory for bigger data sets.
#
# This method returns the duplicate table for chaining. Don't chain
# destructive methods (like []=()) this way though, since you are working
# with a duplicate.
#
def by_row
self.class.new(@table.dup).by_row!
end

#
# Switches the mode of this table to row mode. All calls to indexing and
# iteration methods will work with rows until the mode is changed again.
#
# This method returns the table and is safe to chain.
#
def by_row!
@mode = :row

self
end

#
# Returns the headers for the first row of this table (assumed to match all
# other rows). An empty Array is returned for empty tables.
#
def headers
if @table.empty?
Array.new
else
@table.first.headers
end
end

#
# In the default mixed mode, this method returns rows for index access and
# columns for header access. You can force the index association by first
# calling by_col!() or by_row!().
#
# Columns are returned as an Array of values. Altering that Array has no
# effect on the table.
#
def [](index_or_header)
if @mode == :row or # by index
(@mode == :col_or_row and index_or_header.is_a? Integer)
@table[index_or_header]
else # by header
@table.map { |row| row[index_or_header] }
end
end

#
# In the default mixed mode, this method assigns rows for index access and
# columns for header access. You can force the index association by first
# calling by_col!() or by_row!().
#
# Rows may be set to an Array of values (which will inherit the table's
# headers()) or a CSV::Row.
#
# Columns may be set to a single value, which is copied to each row of the
# column, or an Array of values. Arrays of values are assigned to rows top
# to bottom in row major order. Excess values are ignored and if the Array
# does not have a value for each row the extra rows will receive a +nil+.
#
# Assigning to an existing column or row clobbers the data. Assigning to
# new columns creates them at the right end of the table.
#
def []=(index_or_header, value)
if @mode == :row or # by index
(@mode == :col_or_row and index_or_header.is_a? Integer)
if value.is_a? Array
@table[index_or_header] = Row.new(headers, value)
else
@table[index_or_header] = value
end
else # set column
if value.is_a? Array # multiple values
@table.each_with_index do |row, i|
if row.header_row?
row[index_or_header] = index_or_header
else
row[index_or_header] = value[i]
end
end
else # repeated value
@table.each do |row|
if row.header_row?
row[index_or_header] = index_or_header
else
row[index_or_header] = value
end
end
end
end
end

#
# The mixed mode default is to treat a list of indices as row access,
# returning the rows indicated. Anything else is considered columnar
# access. For columnar access, the return set has an Array for each row
# with the values indicated by the headers in each Array. You can force
# column or row mode using by_col!() or by_row!().
#
# You cannot mix column and row access.
#
def values_at(*indices_or_headers)
if @mode == :row or # by indices
( @mode == :col_or_row and indices_or_headers.all? do |index|
index.is_a?(Integer) or
( index.is_a?(Range) and
index.first.is_a?(Integer) and
index.last.is_a?(Integer) )
end )
@table.values_at(*indices_or_headers)
else # by headers
@table.map { |row| row.values_at(*indices_or_headers) }
end
end

#
# Adds a new row to the bottom end of this table. You can provide an Array,
# which will be converted to a CSV::Row (inheriting the table's headers()),
# or a CSV::Row.
#
# This method returns the table for chaining.
#
def <<(row_or_array)
if row_or_array.is_a? Array # append Array
@table << Row.new(headers, row_or_array)
else # append Row
@table << row_or_array
end

self # for chaining
end

#
# A shortcut for appending multiple rows. Equivalent to:
#
# rows.each { |row| self << row }
#
# This method returns the table for chaining.
#
def push(*rows)
rows.each { |row| self << row }

self # for chaining
end

#
# Removes and returns the indicated column or row. In the default mixed
# mode indices refer to rows and everything else is assumed to be a column
# header. Use by_col!() or by_row!() to force the lookup.
#
def delete(index_or_header)
if @mode == :row or # by index
(@mode == :col_or_row and index_or_header.is_a? Integer)
@table.delete_at(index_or_header)
else # by header
@table.map { |row| row.delete(index_or_header).last }
end
end

#
# Removes any column or row for which the block returns +true+. In the
# default mixed mode or row mode, iteration is the standard row major
# walking of rows. In column mode, interation will +yield+ two element
# tuples containing the column name and an Array of values for that column.
#
# This method returns the table for chaining.
#
def delete_if(&block)
if @mode == :row or @mode == :col_or_row # by index
@table.delete_if(&block)
else # by header
to_delete = Array.new
headers.each_with_index do |header, i|
to_delete << header if block[[header, self[header]]]
end
to_delete.map { |header| delete(header) }
end

self # for chaining
end

include Enumerable

#
# In the default mixed mode or row mode, iteration is the standard row major
# walking of rows. In column mode, interation will +yield+ two element
# tuples containing the column name and an Array of values for that column.
#
# This method returns the table for chaining.
#
def each(&block)
if @mode == :col
headers.each { |header| block[[header, self[header]]] }
else
@table.each(&block)
end

self # for chaining
end

# Returns +true+ if all rows of this table ==() +other+'s rows.
def ==(other)
@table == other.table
end

#
# Returns the table as an Array of Arrays. Headers will be the first row,
# then all of the field rows will follow.
#
def to_a
@table.inject([headers]) do |array, row|
if row.header_row?
array
else
array + [row.fields]
end
end
end

#
# Returns the table as a complete CSV String. Headers will be listed first,
# then all of the field rows.
#
def to_csv(options = Hash.new)
@table.inject([headers.to_csv(options)]) do |rows, row|
if row.header_row?
rows
else
rows + [row.fields.to_csv(options)]
end
end.join
end
alias_method :to_s, :to_csv

# Shows the mode and size of this table in a US-ASCII String.
def inspect
"#<#{self.class} mode:#{@mode} row_count:#{to_a.size}>".encode("US-ASCII")
end
end

# The error thrown when the parser encounters illegal CSV formatting.
class MalformedCSVError < RuntimeError; 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.
#
# <b><tt>index</tt></b>:: The zero-based index of the field in its row.
# <b><tt>line</tt></b>:: The line of the data source this row is from.
# <b><tt>header</tt></b>:: 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} )\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().
#
# <b><tt>:integer</tt></b>:: Converts any field Integer() accepts.
# <b><tt>:float</tt></b>:: Converts any field Float() accepts.
# <b><tt>:numeric</tt></b>:: A combination of <tt>:integer</tt>
# and <tt>:float</tt>.
# <b><tt>:date</tt></b>:: Converts any field Date::parse() accepts.
# <b><tt>:date_time</tt></b>:: Converts any field DateTime::parse() accepts.
# <b><tt>:all</tt></b>:: 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 =~ DateMatcher ? Date.parse(e) : f
rescue # encoding conversion or date parse errors
f
end
},
date_time: lambda { |f|
begin
e = f.encode(ConverterEncoding)
e =~ 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().
#
# <b><tt>:downcase</tt></b>:: Calls downcase() on the header String.
# <b><tt>:symbol</tt></b>:: The header String is downcased, 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 intetionally 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+/, "_").
gsub(/\W+/, "").to_sym
}
}

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

#
# 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 self.instance(data = $stdout, options = Hash.new)
# 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

#
# This method allows you to serialize an Array of Ruby objects to a String or
# File of CSV data. This is not as powerful as Marshal or YAML, but perhaps
# useful for spreadsheet and database interaction.
#
# Out of the box, this method is intended to work with simple data objects or
# Structs. It will serialize a list of instance variables and/or
# Struct.members().
#
# If you need need more complicated serialization, you can control the process
# by adding methods to the class to be serialized.
#
# A class method csv_meta() is responsible for returning the first row of the
# document (as an Array). This row is considered to be a Hash of the form
# key_1,value_1,key_2,value_2,... CSV::load() expects to find a class key
# with a value of the stringified class name and CSV::dump() will create this,
# if you do not define this method. This method is only called on the first
# object of the Array.
#
# The next method you can provide is an instance method called csv_headers().
# This method is expected to return the second line of the document (again as
# an Array), which is to be used to give each column a header. By default,
# CSV::load() will set an instance variable if the field header starts with an
# @ character or call send() passing the header as the method name and
# the field value as an argument. This method is only called on the first
# object of the Array.
#
# Finally, you can provide an instance method called csv_dump(), which will
# be passed the headers. This should return an Array of fields that can be
# serialized for this object. This method is called once for every object in
# the Array.
#
# The +io+ parameter can be used to serialize to a File, and +options+ can be
# anything CSV::new() accepts.
#
def self.dump(ary_of_objs, io = "", options = Hash.new)
obj_template = ary_of_objs.first

csv = new(io, options)

# write meta information
begin
csv << obj_template.class.csv_meta
rescue NoMethodError
csv << [:class, obj_template.class]
end

# write headers
begin
headers = obj_template.csv_headers
rescue NoMethodError
headers = obj_template.instance_variables.sort
if obj_template.class.ancestors.find { |cls| cls.to_s =~ /\AStruct\b/ }
headers += obj_template.members.map { |mem| "#{mem}=" }.sort
end
end
csv << headers

# serialize each object
ary_of_objs.each do |obj|
begin
csv << obj.csv_dump(headers)
rescue NoMethodError
csv << headers.map do |var|
if var[0] == ?@
obj.instance_variable_get(var)
else
obj[var[0..-2]]
end
end
end
end

if io.is_a? String
csv.string
else
csv.close
end
end

#
# This method is the reading counterpart to CSV::dump(). See that method for
# a detailed description of the process.
#
# You can customize loading by adding a class method called csv_load() which
# will be passed a Hash of meta information, an Array of headers, and an Array
# of fields for the object the method is expected to return.
#
# Remember that all fields will be Strings after this load. If you need
# something else, use +options+ to setup converters or provide a custom
# csv_load() implementation.
#
def self.load(io_or_str, options = Hash.new)
csv = new(io_or_str, options)

# load meta information
meta = Hash[*csv.shift]
cls = meta["class".encode(csv.encoding)].split("::".encode(csv.encoding)).
inject(Object) do |c, const|
c.const_get(const)
end

# load headers
headers = csv.shift

# unserialize each object stored in the file
results = csv.inject(Array.new) do |all, row|
begin
obj = cls.csv_load(meta, headers, row)
rescue NoMethodError
obj = cls.allocate
headers.zip(row) do |name, value|
if name[0] == ?@
obj.instance_variable_set(name, value)
else
obj.send(name, value)
end
end
end
all << obj
end

csv.close unless io_or_str.is_a? String

results
end

#
# :call-seq:
# filter( options = Hash.new ) { |row| ... }
# filter( input, options = Hash.new ) { |row| ... }
# filter( input, output, options = Hash.new ) { |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 self.filter(*args)
# parse options for input, output, or both
in_options, out_options = Hash.new, {row_sep: $INPUT_RECORD_SEPARATOR}
if args.last.is_a? Hash
args.pop.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
end
# build input and output wrappers
input = new(args.shift || ARGF, in_options)
output = new(args.shift || $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 deterime 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 self.foreach(path, options = Hash.new, &block)
encoding = options.delete(:encoding)
mode = "rb"
mode << ":#{encoding}" if encoding
open(path, mode, options) do |csv|
csv.each(&block)
end
end

#
# :call-seq:
# generate( str, options = Hash.new ) { |csv| ... }
# generate( options = Hash.new ) { |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* modfied by this method. Call dup() before
# passing if you need a new String.
#
# The +options+ parameter can be anthing 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 self.generate(*args)
# add a default empty String, if none was given
if args.first.is_a? String
io = StringIO.new(args.shift)
io.seek(0, IO::SEEK_END)
args.unshift(io)
else
encoding = args.last.is_a?(Hash) ? args.last.delete(:encoding) : nil
str = ""
str.encode!(encoding) if encoding
args.unshift(str)
end
csv = new(*args) # 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 anthing 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 self.generate_line(row, options = Hash.new)
options = {row_sep: $INPUT_RECORD_SEPARATOR}.merge(options)
encoding = options.delete(:encoding)
str = ""
if encoding
str.force_encoding(encoding)
elsif field = row.find { |f| not f.nil? }
str.force_encoding(String(field).encoding)
end
(new(str, options) << row).string
end

#
# :call-seq:
# open( filename, mode = "rb", options = Hash.new ) { |faster_csv| ... }
# open( filename, options = Hash.new ) { |faster_csv| ... }
# open( filename, mode = "rb", options = Hash.new )
# open( filename, options = Hash.new )
#
# 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 deterime 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 self.open(*args)
# find the +options+ Hash
options = if args.last.is_a? Hash then args.pop else Hash.new end
# default to a binary open mode
args << "rb" if args.size == 1
# wrap a File opened with the remaining +args+
csv = new(File.open(*args), options)

# 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 = Hash.new ) { |row| ... }
# parse( str, options = Hash.new )
#
# 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+ Hash containing
# anything CSV::new() understands.
#
def self.parse(*args, &block)
csv = new(*args)
if block.nil? # slurp contents, if no block is given
begin
csv.read
ensure
csv.close
end
else # or pass each row to a provided block
csv.each(&block)
end
end

#
# This method is a shortcut for converting a single line of a CSV String into
# a into an Array. Note that if +line+ contains multiple rows, anything
# beyond the first row is ignored.
#
# The +options+ parameter can be anthing CSV::new() understands.
#
def self.parse_line(line, options = Hash.new)
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 deterime
# 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 self.read(path, options = Hash.new)
encoding = options.delete(:encoding)
mode = "rb"
mode << ":#{encoding}" if encoding
open(path, mode, options) { |csv| csv.read }
end

# Alias for CSV::read().
def self.readlines(*args)
read(*args)
end

#
# A shortcut for:
#
# CSV.read( path, { headers: true,
# converters: :numeric,
# header_converters: :symbol }.merge(options) )
#
def self.table(path, options = Hash.new)
read( path, { headers: true,
converters: :numeric,
header_converters: :symbol }.merge(options) )
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 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:
#
# <b><tt>:col_sep</tt></b>:: The String placed between each field.
# This String will be transcoded into
# the data's Encoding before parsing.
# <b><tt>:row_sep</tt></b>:: 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.
# <b><tt>:quote_char</tt></b>:: 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 this character to be an
# escaped quote. This String will be
# transcoded into the data's Encoding
# before parsing.
# <b><tt>:field_size_limit</tt></b>:: 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.
# <b><tt>:converters</tt></b>:: 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.
# <b><tt>:unconverted_fields</tt></b>:: 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.
# <b><tt>:headers</tt></b>:: 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.
# <b><tt>:return_headers</tt></b>:: 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).
# <b><tt>:write_headers</tt></b>:: When +true+ and <tt>:headers</tt> is
# set, a header row will be added to the
# output.
# <b><tt>:header_converters</tt></b>:: 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.
# <b><tt>:skip_blanks</tt></b>:: When set to a +true+ value, CSV will
# skip over any rows with no content.
# <b><tt>:force_quotes</tt></b>:: When set to a +true+ value, CSV will
# quote all CSV fields it creates.
#
# See CSV::DEFAULT_OPTIONS for the default settings.
#
# Options cannot be overriden in the instance methods for performance reasons,
# so be sure to set what you want here.
#
def initialize(data, options = Hash.new)
# build the options for this read/write
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
# honor the IO encoding if we can, otherwise default to ASCII-8BIT
@encoding = if @io.respond_to? :internal_encoding
@io.internal_encoding || @io.external_encoding
elsif @io.is_a? StringIO
@io.string.encoding
end
@encoding ||= Encoding.default_internal || Encoding.default_external
#
# prepare for building safe regular expressions in the target encoding,
# if we can transcode the needed characters
#
@re_esc = "\\".encode(@encoding) rescue ""
@re_chars = %w[ \\ . [ ] - ^ $ ?
* + { } ( ) | #
\ \r \n \t \f \v ].
map { |s| s.encode(@encoding) rescue nil }.compact

init_separators(options)
init_parsers(options)
init_converters(options)
init_headers(options)

unless options.empty?
raise ArgumentError, "Unknown options: #{options.keys.join(', ')}."
end

# track our own lineno since IO gets confused about line-ends is CSV fields
@lineno = 0
end

#
# The encoded <tt>:col_sep</tt> used in parsing and writing. See CSV::new
# for details.
#
attr_reader :col_sep
#
# The encoded <tt>:row_sep</tt> used in parsing and writing. See CSV::new
# for details.
#
attr_reader :row_sep
#
# The encoded <tt>:quote_char</tt> used in parsing and writing. See CSV::new
# for details.
#
attr_reader :quote_char
# The limit for field size, if any. See CSV::new for details.
attr_reader :field_size_limit
#
# 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
@converters.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?() @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
@headers || true if @use_headers
end
#
# Returns +true+ if headers will be returned as a row of results.
# See CSV::new for details.
#
def return_headers?() @return_headers end
# Returns +true+ if headers are written in output. See CSV::new for details.
def write_headers?() @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_converters.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?() @skip_blanks end
# Returns +true+ if all output fields are quoted. See CSV::new for details.
def force_quotes?() @force_quotes 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.
#
attr_reader :lineno

### IO and StringIO Delegation ###

extend Forwardable
def_delegators :@io, :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, :string, :sync, :sync=, :tell, :to_i,
:to_io, :truncate, :tty?

# Rewinds the underlying IO object and resets CSV's lineno() counter.
def rewind
@headers = nil
@lineno = 0

@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)
# make sure headers have been assigned
if header_row? and [Array, String].include? @use_headers.class
parse_headers # won't read data for Array or String
self << @headers if @write_headers
end

# handle CSV::Row objects and Hashes
row = case row
when self.class::Row then row.fields
when Hash then @headers.map { |header| row[header] }
else row
end

@headers = row if header_row?
@lineno += 1

@io << row.map(&@quote).join(@col_sep) + @row_sep # quote and separate

self # for chaining
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)
add_converter(:converters, self.class::Converters, 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)
add_converter( :header_converters,
self.class::HeaderConverters,
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
while row = shift
yield row
end
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 @use_headers
Table.new(rows)
else
rows
end
end
alias_method :readlines, :read

# Returns +true+ if the next row read will be a header row.
def header_row?
@use_headers and @headers.nil?
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
#########################################################################
### This method is purposefully kept a bit long as simple conditional ###
### checks are faster than numerous (expensive) method calls. ###
#########################################################################

# handle headers not based on document content
if header_row? and @return_headers and
[Array, String].include? @use_headers.class
if @unconverted_fields
return add_unconverted_fields(parse_headers, Array.new)
else
return parse_headers
end
end

# begin with a blank line, so we can always add to it
line = ""

#
# it can take multiple calls to <tt>@io.gets()</tt> to get a full line,
# because of \r and/or \n characters embedded in quoted fields
#
in_extended_col = false
csv = Array.new

loop do
# add another read to the line
parse = (@io.gets(@row_sep)) rescue nil
return nil unless parse

parse.sub!(@parsers[:line_end], "")

if csv.empty?
#
# I believe a blank line should be an <tt>Array.new</tt>, not Ruby 1.8
# CSV's <tt>[nil]</tt>
#
if parse.empty?
@lineno += 1
if @skip_blanks
next
elsif @unconverted_fields
return add_unconverted_fields(Array.new, Array.new)
elsif @use_headers
return self.class::Row.new(Array.new, Array.new)
else
return Array.new
end
end
end

parts = parse.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) % 2 != 0
# extended column ends
csv.last << part[0..-2]
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 staring a new quoted column
if part[-1] != @quote_char || part.count(@quote_char) % 2 != 0
# start an extended column
csv << part[1..-1]
csv.last << @col_sep
in_extended_col = true
else
# regular quoted column
csv << part[1..-2]
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 on 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

if in_extended_col
# if we're at eof?(), a quoted field wasn't closed...
if @io.eof?
raise MalformedCSVError, "Unclosed quoted field on line #{lineno + 1}."
elsif @field_size_limit and csv.last.size >= @field_size_limit
raise MalformedCSVError, "Field size exceeded on line #{lineno + 1}."
end
# otherwise, we need to loop and pull some more data to complete the row
else
@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 or @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...
if @unconverted_fields and not csv.respond_to? :unconverted_fields
add_unconverted_fields(csv, unconverted)
end

# return the results
break csv
end
end
end
alias_method :gets, :shift
alias_method :readline, :shift

#
# Returns a simplified description of the key FasterCSV 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
%w[ lineno col_sep row_sep
quote_char skip_blanks ].each do |attr_name|
if a = instance_variable_get("@#{attr_name}")
str << " " << attr_name << ":" << a.inspect
end
end
if @use_headers
str << " headers:" << headers.inspect
end
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

#
# Stores the indicated separators for later use.
#
# If auto-discovery was requested for <tt>@row_sep</tt>, this method will read
# ahead in the <tt>@io</tt> and try to find one. +ARGF+, +STDIN+, +STDOUT+,
# +STDERR+ and any stream open for output only with a default
# <tt>@row_sep</tt> of <tt>$INPUT_RECORD_SEPARATOR</tt> (<tt>$/</tt>).
#
# This method also establishes the quoting rules used for CSV output.
#
def init_separators(options)
# store the selected separators
@col_sep = options.delete(:col_sep).to_s.encode(@encoding)
@row_sep = options.delete(:row_sep) # encode after resolving :auto
@quote_char = options.delete(:quote_char).to_s.encode(@encoding)

if @quote_char.length != 1
raise ArgumentError, ":quote_char has to be a single character String"
end

#
# automatically discover row separator when requested
# (not fully encoding safe)
#
if @row_sep == :auto
if [ARGF, STDIN, STDOUT, STDERR].include?(@io) or
(defined?(Zlib) and @io.class == Zlib::GzipWriter)
@row_sep = $INPUT_RECORD_SEPARATOR
else
begin
saved_pos = @io.pos # remember where we were
while @row_sep == :auto
#
# if we run out of data, it's probably a single line
# (use a sensible default)
#
if @io.eof?
@row_sep = $INPUT_RECORD_SEPARATOR
break
end

# read ahead a bit
sample = read_to_char(1024)
sample += read_to_char(1) if sample[-1..-1] == encode_str("\r") and
not @io.eof?

# try to find a standard separator
if sample =~ encode_re("\r\n?|\n")
@row_sep = $&
break
end
end
# tricky seek() clone to work around GzipReader's lack of seek()
@io.rewind
# reset back to the remembered position
while saved_pos > 1024 # avoid loading a lot of data into memory
@io.read(1024)
saved_pos -= 1024
end
@io.read(saved_pos) if saved_pos.nonzero?
rescue IOError # stream not opened for reading
@row_sep = $INPUT_RECORD_SEPARATOR
end
end
end
@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
end
quotable_chars = encode_str("\r\n", @col_sep, @quote_char)
@quote = if @force_quotes
do_quote
else
lambda do |field|
if field.nil? # represent +nil+ fields as empty unquoted fields
""
else
field = String(field) # Stringify fields
# represent empty fields as empty quoted fields
if field.empty? or
field.count(quotable_chars).nonzero?
do_quote.call(field)
else
field # unquoted field
end
end
end
end
end

# Pre-compiles parsers and stores them by name for access during reads.
def init_parsers(options)
# store the parser behaviors
@skip_blanks = options.delete(:skip_blanks)
@field_size_limit = options.delete(:field_size_limit)

# prebuild Regexps for faster parsing
esc_col_sep = escape_re(@col_sep)
esc_row_sep = escape_re(@row_sep)
esc_quote = escape_re(@quote_char)
@parsers = {
# for detecting parse errors
quote_or_nl: encode_re("[", esc_quote, "\r\n]"),
nl_or_lf: encode_re("[\r\n]"),
# safer than chomp!()
line_end: encode_re(esc_row_sep, "\\z"),
# illegal unquoted characters
return_newline: encode_str("\r\n")
}
end

#
# Loads any converters requested during construction.
#
# If +field_name+ is set <tt>:converters</tt> (the default) field converters
# are set. When +field_name+ is <tt>:header_converters</tt> header converters
# are added instead.
#
# The <tt>:unconverted_fields</tt> option is also actived for
# <tt>:converters</tt> calls, if requested.
#
def init_converters(options, field_name = :converters)
if field_name == :converters
@unconverted_fields = options.delete(:unconverted_fields)
end

instance_variable_set("@#{field_name}", Array.new)

# find the correct method to add the converters
convert = method(field_name.to_s.sub(/ers\Z/, ""))

# load converters
unless options[field_name].nil?
# allow a single converter not wrapped in an Array
unless options[field_name].is_a? Array
options[field_name] = [options[field_name]]
end
# load each converter...
options[field_name].each do |converter|
if converter.is_a? Proc # custom code block
convert.call(&converter)
else # by name
convert.call(converter)
end
end
end

options.delete(field_name)
end

# Stores header row settings and loads header converters, if needed.
def init_headers(options)
@use_headers = options.delete(:headers)
@return_headers = options.delete(:return_headers)
@write_headers = options.delete(:write_headers)

# headers must be delayed until shift(), in case they need a row of content
@headers = nil

init_converters(options, :header_converters)
end

#
# The actual work method for adding converters, used by both CSV.convert() and
# CSV.header_convert().
#
# This method requires the +var_name+ of the instance variable to place the
# converters in, the +const+ Hash to lookup named converters in, and the
# normal parameters of the CSV.convert() and CSV.header_convert() methods.
#
def add_converter(var_name, const, name = nil, &converter)
if name.nil? # custom converter
instance_variable_get("@#{var_name}") << converter
else # named converter
combo = const[name]
case combo
when Array # combo converter
combo.each do |converter_name|
add_converter(var_name, const, converter_name)
end
else # individual named converter
instance_variable_get("@#{var_name}") << combo
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)
# see if we are converting headers or fields
converters = headers ? @header_converters : @converters

fields.map.with_index do |field, index|
converters.each do |converter|
field = if converter.arity == 1 # straight field converter
converter[field]
else # FieldInfo converter
header = @use_headers && !headers ? @headers[index] : nil
converter[field, FieldInfo.new(index, lineno, header)]
end
break unless field.is_a? String # short-curcuit pipeline for speed
end
field # final state of each field, converted or original
end
end

#
# This methods is used to turn a finished +row+ into a CSV::Row. Header rows
# are also dealt with here, either by returning a CSV::Row with identical
# headers and fields (save that the fields do not go through the converters)
# or by reading past them to return a field row. Headers are also saved in
# <tt>@headers</tt> for use in future rows.
#
# When +nil+, +row+ is assumed to be a header row not based on an actual row
# of the stream.
#
def parse_headers(row = nil)
if @headers.nil? # header row
@headers = case @use_headers # save headers
# Array of headers
when Array then @use_headers
# CSV header String
when String
self.class.parse_line( @use_headers,
col_sep: @col_sep,
row_sep: @row_sep,
quote_char: @quote_char )
# first row is headers
else row
end

# prepare converted and unconverted copies
row = @headers if row.nil?
@headers = convert_fields(@headers, true)

if @return_headers # return headers
return self.class::Row.new(@headers, row, true)
elsif not [Array, String].include? @use_headers.class # skip to field row
return shift
end
end

self.class::Row.new(@headers, convert_fields(row)) # field row
end

#
# Thiw methods injects an instance variable <tt>unconverted_fields</tt> into
# +row+ and an accessor method for it called unconverted_fields(). The
# variable is set to the contents of +fields+.
#
def add_unconverted_fields(row, fields)
class << row
attr_reader :unconverted_fields
end
row.instance_eval { @unconverted_fields = fields }
row
end

#
# This method is an encoding safe version of Regexp::escape(). It will escape
# any characters that would change the meaning of a regular expression in the
# encoding of +str+. Regular expression characters that cannot be transcoded
# to the target encoding will be skipped and no escaping will be performed if
# a backslash cannot be transcoded.
#
def escape_re(str)
str.chars.map { |c| @re_chars.include?(c) ? @re_esc + c : c }.join
end

#
# Builds a regular expression in <tt>@encoding</tt>. All +chunks+ will be
# transcoded to that encoding.
#
def encode_re(*chunks)
Regexp.new(encode_str(*chunks))
end

#
# Builds a String in <tt>@encoding</tt>. All +chunks+ will be transcoded to
# that encoding.
#
def encode_str(*chunks)
chunks.map { |chunk| chunk.encode(@encoding.name) }.join
end

#
# Reads at least +bytes+ from <tt>@io</tt>, but will read up 10 bytes ahead if
# needed to ensure the data read is valid in the ecoding of that data. This
# should ensure that it is safe to use regular expressions on the read data,
# unless it is actually a broken encoding. The read data will be returned in
# <tt>@encoding</tt>.
#
def read_to_char(bytes)
return "" if @io.eof?
data = @io.read(bytes)
begin
encoded = encode_str(data)
raise unless encoded.valid_encoding?
return encoded
rescue # encoding error or my invalid data raise
if @io.eof? or data.size >= bytes + 10
return data
else
data += @io.read(1)
retry
end
end
end
end

# Another name for CSV::instance().
def CSV(*args, &block)
CSV.instance(*args, &block)
end

class Array
# Equivalent to <tt>CSV::generate_line(self, options)</tt>.
def to_csv(options = Hash.new)
CSV.generate_line(self, options)
end
end

class String
# Equivalent to <tt>CSV::parse_line(self, options)</tt>.
def parse_csv(options = Hash.new)
CSV.parse_line(self, options)
end
end
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