# ==============================================================================
# EXTENDING CLASS STRING
# ==============================================================================
#
# (C) Copyright 2004 by Tilo Sloboda <tools@unixgods.org>
#
# License:
#         Freely available under the terms of the OpenSource "Artistic License"
#         in combination with the Addendum A (below)
#
#         In case you did not get a copy of the license along with the software,
#         it is also available at:   http://www.unixgods.org/~tilo/artistic-license.html
#
# Addendum A:
#         THE ENTIRE RISK AS TO THE QUALITY AND PERFORMANCE OF THE PROGRAM IS WITH YOU!
#         SHOULD THE PROGRAM PROVE DEFECTIVE, YOU ASSUME THE COST OF ALL NECESSARY SERVICING,
#         REPAIR OR CORRECTION.
#
#         IN NO EVENT WILL THE COPYRIGHT HOLDERS  BE LIABLE TO YOU FOR DAMAGES, INCLUDING ANY GENERAL,
#         SPECIAL, INCIDENTAL OR CONSEQUENTIAL DAMAGES ARISING OUT OF THE USE OR INABILITY
#         TO USE THE PROGRAM (INCLUDING BUT NOT LIMITED TO LOSS OF DATA OR DATA BEING RENDERED
#         INACCURATE OR USELESS OR LOSSES SUSTAINED BY YOU OR THIRD PARTIES OR A FAILURE OF THE PROGRAM
#         TO OPERATE WITH ANY OTHER PROGRAMS), EVEN IF THE COPYRIGHT HOLDERS OR OTHER PARTY HAS BEEN
#         ADVISED OF THE POSSIBILITY OF SUCH DAMAGES.


class String
  #
  # prints out a good'ol hexdump of the data contained in the string
  #
  # parameters:     sparse:   true / false     do we want to print multiple lines with zero values?

  def hexdump(sparse = false)
     selfsize = self.size
     first = true

     print "\n index       0 1 2 3  4 5 6 7  8 9 A B  C D E F\n\n"

     lines,rest = selfsize.divmod(16)
     address = 0; i = 0    # we count them independently for future extension.

     while lines > 0
        str = self[i..i+15]
        
        # we don't print lines with all zeroes, unless it's the last line

        if str == "\0"*16     # if the 16 bytes are all zero
        
          if (!sparse) || (sparse &&  lines == 1 && rest == 0)
             str.tr!("\000-\037\177-\377",'.')
             printf( "%08x    %8s %8s %8s %8s    %s\n", 
                address, self[i..i+3].unpack('H8'), self[i+4..i+7].unpack('H8'),
                self[i+8..i+11].unpack('H8'), self[i+12..i+15].unpack('H8'), str)
          else
                print "  ....      00 .. 00 00 .. 00 00 .. 00 00 .. 00    ................\n" if first
                first = false
	  end

        else  # print string which is not all zeros

          str.tr!("\000-\037\177-\377",'.')
          printf( "%08x    %8s %8s %8s %8s    %s\n", 
                address, self[i..i+3].unpack('H8'), self[i+4..i+7].unpack('H8'),
                self[i+8..i+11].unpack('H8'), self[i+12..i+15].unpack('H8'), str)
          first = true
	end
        i += 16; address += 16; lines -= 1
     end
     
     # now do the remaining bytes, which don't fit a full line..
     # yikes - this is truly ugly!  REWRITE THIS!!

     if rest > 0
        chunks2,rest2 = rest.divmod(4)     
        j = i; k = 0
        if (i < selfsize)
           printf( "%08x    ", address)
           while (i < selfsize)
                printf "%02x", self[i]
                i += 1; k += 1
                print  " " if ((i % 4) == 0)
           end
           for i in (k..15)
                  print "  "
           end
           str = self[j..selfsize]
           str.tr!("\000-\037\177-\377",'.')
           print " " * (4 - chunks2+1)
           printf("  %s\n", str)
        end
     end
  end

end



__END__

require 'hexdump'

s =  "some random long string"

t =  s << "\0"*40  << s << "\0"*32 << s << "bla bla bla!"
t.hexdump(true)
t.hexdump(false)

4.times {t.chop!}

t.hexdump(true)
t.hexdump(false)