#!/usr/local/bin/ruby -w

class String

   def stripped!                                 
      gsub!(/^[[:space:]]*|[[:space:]]*$/, '')   # whitespace characters: [ \t\r\n\v\f]
   end                                           # cf. http://en.wikipedia.org/wiki/Regular_expression

   def lstripped!
      sub!(/^[[:space:]]*/, '')
   end

   def rstripped!
      sub!(/[[:space:]]*$/, '')
   end

   def stripped_all!
      gsub!(/^[[:cntrl:]\x20]*|[[:cntrl:]\x20]*$/, '')   # control characters: [\x00-\x1F\x7F] and space character: \x20
   end                                                   # cf. http://en.wikipedia.org/wiki/ASCII#ASCII_control_characters

   def lstripped_all!
      sub!(/^[[:cntrl:]\x20]*/, '')
   end

   def rstripped_all!
      sub!(/[[:cntrl:]\x20]*$/, '')
   end

   def delete_cntrl!
      return self unless self =~ /[[:cntrl:]]/ 
      gsub!(/[[:cntrl:]]/, '')
      #str = gsub!(/[[:cntrl:]]/, '')   # alternative
      #str.nil? ? self : str
   end

end


p "".strip!       #=> nil
p "".stripped!    #=> ""

p "abc".strip!       #=> nil
p "abc".stripped!    #=> "abc"

p "abc\000".strip!           #=> "abc" (!)
p "abc\000".stripped_all!    #=> "abc"

p "abc\000\001".strip!           #=> nil
p "abc\000\001".stripped_all!    #=> "abc"

puts

p "".gsub!(/[[:cntrl:]]/, '')   #=> nil
p "a".gsub!(/[[:cntrl:]]/, '')  #=> nil

p "".delete_cntrl!    #=> ""
p "a".delete_cntrl!   #=> "a"



text = <<-EOS
 \r \x00 this is an example \t\x11 text  caf\303\251 \x20\x20\x20\x20 \r \f

  \011  \x10 \x07  \t\r\v\f abc \v\000 def \000 \x20\x20 \r  \v \r
EOS


puts "\n\n\e[1mOriginal text:\e[m\n"
text.each_line { |l| p l }

puts

puts "\n\e[1mString#stripped!\e[m\n"
text.each_line do |l| 
   l.stripped!
   p l
end

puts "\n\e[1mString#lstripped!\e[m\n"
text.each_line do |l| 
   l.lstripped!
   p l
end

puts "\n\e[1mString#rstripped!\e[m\n"
text.each_line do |l| 
   l.rstripped!
   p l
end

puts "\n\e[1mString#stripped_all!\e[m\n"
text.each_line do |l| 
   l.stripped_all!
   p l
end

puts "\n\e[1mString#lstripped_all!\e[m\n"
text.each_line do |l| 
   l.lstripped_all!
   p l
end

puts "\n\e[1mString#rstripped_all!\e[m\n"
text.each_line do |l| 
   l.rstripped_all!
   p l
end

puts "\n\e[1mString#delete_cntrl!\e[m\n"
text.each_line do |l| 
   l.delete_cntrl!
   #l.delete_cntrl!.stripped_all!
   p l
end