split-and-loop-vs-regexp-and-make-hash.rb

split-and-loop-vs-regexp-and-make-hash.rb

# Sisimai::Message improvement
require 'benchmark'
require 'sisimai/string'
require 'sisimai/rfc5322'
require 'sisimai/mime'

HowMany = 30000
RFC822Head = Sisimai::RFC5322.HEADERFIELDS
BorderLine = '__MIME_ENCODED_BOUNDARY__'
FieldTable = %r/(
     apparently-to
    |date
    |delivered-to
    |envelope-from
    |envelope-to
    |errors-to
    |forward-path
    |from
    |list-id
    |message-id
    |posted
    |posted-date
    |reply-to
    |resent-date
    |resent-to
    |reverse-path
    |return-path
    |subject
    |to
    |x-envelope-from
    |x-envelope-to
    |x-postfix-sender
)/imx

Head = <<'EOH'
Return-Path: <[email protected]>
Received: from [192.0.2.25] (p0000-ipbfpfx00kyoto.kyoto.example.co.jp [192.0.2.25])
	(authenticated bits=0)
	by smtpgw.example.jp (V8/cf) with ESMTP id r9G5FXh9018568
	for <[email protected]>; Wed, 16 Oct 2013 14:15:34 +0900
From: "Kijitora Cat" <[email protected]>
Content-Type: text/plain; charset=utf-8
Content-Transfer-Encoding: base64
Subject: =?utf-8?B?44OQ44Km44Oz44K544Oh44O844Or44Gu44OG44K544OIKOaXpQ==?=
 =?utf-8?B?5pys6KqeKQ==?=
Date: Wed, 16 Oct 2013 14:15:35 +0900
Message-Id: <[email protected]>
To: [email protected]
Mime-Version: 1.0 (Apple Message framework v1283)
X-Mailer: Apple Mail (2.1283)
EOH

def takeapart(heads)
  return {} unless heads

  # 1. Scrub to avoid "invalid byte sequence in UTF-8" exception (#82)
  # 2. Convert from string to hash reference
  heads = heads.scrub('?').gsub(/^[>]+[ ]/m, '').gsub(/=[ ]+=/, "=\n =")

  previousfn = '' # Previous field name
  asciiarmor = {} # Header names which has MIME encoded value
  headerpart = {} # Required headers in the original message part
  headslices = heads.split("\n")

  while e = headslices.shift do
    # Header name as a key, The value of header as a value
    if e.start_with?(' ', "\t")
      # Continued (foled) header value from the previous line
      next if previousfn.empty?

      # Concatenate the line if it is the value of required header
      if Sisimai::MIME.is_mimeencoded(e)
        # The line is MIME-Encoded test
        headerpart[previousfn] << if previousfn == 'subject'
                                    # Subject: header
                                    BorderLine + e
                                  else
                                    # Is not Subject header
                                    e
                                  end
        asciiarmor[previousfn] = true
      else
        # ASCII Characters only: Not MIME-Encoded
        headerpart[previousfn] << e.lstrip
        asciiarmor[previousfn] ||= false
      end
    else
      # Header name as a key, The value of header as a value
      (lhs, rhs) = e.split(/:[ ]*/, 2)
      next unless lhs
      lhs.downcase!
      previousfn = ''

      next unless RFC822Head[lhs]
      previousfn = lhs
      headerpart[previousfn] = rhs unless headerpart[previousfn]
    end
  end
  return headerpart unless headerpart['subject']

  # Convert MIME-Encoded subject
  if Sisimai::String.is_8bit(headerpart['subject'])
    # The value of ``Subject'' header is including multibyte character,
    # is not MIME-Encoded text.
    headerpart['subject'].scrub!('?')
  else
    # MIME-Encoded subject field or ASCII characters only
    r = []
    if asciiarmor['subject']
      # split the value of Subject by borderline
      headerpart['subject'].split(BorderLine).each do |v|
        # Insert value to the array if the string is MIME encoded text
        r << v if Sisimai::MIME.is_mimeencoded(v)
      end
    else
      # Subject line is not MIME encoded
      r << headerpart['subject']
    end
    headerpart['subject'] = Sisimai::MIME.mimedecode(r)
  end
  return headerpart
end

def useregex1(heads)
  return {} unless heads

  # 1. Scrub to avoid "invalid byte sequence in UTF-8" exception (#82)
  # 2. Convert from string to hash reference
  heads = heads.scrub('?').gsub(/^[>]+[ ]/m, '').gsub(/=[ ]+=/, "=\n =")
  table = {};

  heads.scan(/^([\w-]+):[ ]*(.*?)\n(?![\s\t])/m) { |e| table[e[0].downcase] = e[1] }
  return table if table['subject'].empty?

  # Convert MIME-Encoded subject
  if Sisimai::String.is_8bit(table['subject'])
    # The value of ``Subject'' header is including multibyte character,
    # is not MIME-Encoded text.
    table['subject'].scrub!('?')
  else
    # MIME-Encoded subject field or ASCII characters only
    r = []
    if Sisimai::MIME.is_mimeencoded(table['subject'])
      # split the value of Subject by borderline
      table['subject'].split(/ /).each do |v|
        # Insert value to the array if the string is MIME encoded text
        r << v if Sisimai::MIME.is_mimeencoded(v)
      end
    else
      # Subject line is not MIME encoded
      r << table['subject']
    end
    table['subject'] = Sisimai::MIME.mimedecode(r)
  end
  return table
end

def useregex2(heads)
  return {} unless heads

  # 1. Scrub to avoid "invalid byte sequence in UTF-8" exception (#82)
  # 2. Convert from string to hash reference
  heads = heads.scrub('?').gsub(/^[>]+[ ]/m, '').gsub(/=[ ]+=/, "=\n =")
  table = {};

  heads.scan(/^#{FieldTable}:[ ]*(.*?)\n(?![\s\t])/m) { |e| table[e[0].downcase] = e[1] }
  return table if table['subject'].empty?

  # Convert MIME-Encoded subject
  if Sisimai::String.is_8bit(table['subject'])
    # The value of ``Subject'' header is including multibyte character,
    # is not MIME-Encoded text.
    table['subject'].scrub!('?')
  else
    # MIME-Encoded subject field or ASCII characters only
    r = []
    if Sisimai::MIME.is_mimeencoded(table['subject'])
      # split the value of Subject by borderline
      table['subject'].split(/ /).each do |v|
        # Insert value to the array if the string is MIME encoded text
        r << v if Sisimai::MIME.is_mimeencoded(v)
      end
    else
      # Subject line is not MIME encoded
      r << table['subject']
    end
    table['subject'] = Sisimai::MIME.mimedecode(r)
  end
  return table
end

def useregex3(heads)
  return {} unless heads

  # 1. Scrub to avoid "invalid byte sequence in UTF-8" exception (#82)
  # 2. Convert from string to hash reference
  heads = heads.scrub('?').gsub(/^[>]+[ ]/m, '').gsub(/=[ ]+=/, "=\n =")
  table = {};

  heads.scan(/^#{FieldTable}:[ ]*(.*?)\n(?![\s\t])/mo) { |e| table[e[0].downcase] = e[1] }
  return table if table['subject'].empty?

  # Convert MIME-Encoded subject
  if Sisimai::String.is_8bit(table['subject'])
    # The value of ``Subject'' header is including multibyte character,
    # is not MIME-Encoded text.
    table['subject'].scrub!('?')
  else
    # MIME-Encoded subject field or ASCII characters only
    r = []
    if Sisimai::MIME.is_mimeencoded(table['subject'])
      # split the value of Subject by borderline
      table['subject'].split(/ /).each do |v|
        # Insert value to the array if the string is MIME encoded text
        r << v if Sisimai::MIME.is_mimeencoded(v)
      end
    else
      # Subject line is not MIME encoded
      r << table['subject']
    end
    table['subject'] = Sisimai::MIME.mimedecode(r)
  end
  return table
end

p = [takeapart(Head), useregex1(Head), useregex2(Head), useregex3(Head)]
p.each do |e|
  puts 'ok' if e.is_a? Hash
  %w|from subject date to return-path message-id|.each do |ee|
    puts 'ok' if e[ee].size > 0
  end

  puts 'ok' if e['from'] =~ /kijitora/
  puts 'ok' if e['subject'] =~ /繝舌え繝ｳ繧ｹ/
  puts 'ok' if e['date'] =~ /Wed, 16 Oct/
  puts 'ok' if e['to'] =~ /bouncehammer[.]jp/
  puts 'ok' if e['return-path'] =~ /example[.]org/
  puts 'ok' if e['message-id'] =~ /BC36/
end

Benchmark.bmbm do |b|
  b.report('takeapart') do
    HowMany.times do
      takeapart(Head)
    end
  end
  b.report('useregex1') do
    HowMany.times do
      useregex1(Head)
    end
  end
  b.report('useregex2') do
    HowMany.times do
      useregex2(Head)
    end
  end
  b.report('useregex3') do
    HowMany.times do
      useregex3(Head)
    end
  end
end

__END__
Rehearsal ---------------------------------------------
takeapart   1.690759   0.004814   1.695573 (  1.713718)
useregex1   1.632277   0.002730   1.635007 (  1.641662)
useregex2   3.566479   0.004850   3.571329 (  3.578703)
useregex3   1.497352   0.002813   1.500165 (  1.504279)
------------------------------------ total: 8.402074sec

                user     system      total        real
takeapart   1.659426   0.002044   1.661470 (  1.668322)
useregex1   1.686137   0.002063   1.688200 (  1.691882)
useregex2   3.609357   0.003275   3.612632 (  3.617397)
useregex3   1.552407   0.002338   1.554745 (  1.558926)