From: Jos Backus <josb@...>
Date: 2002-01-26T04:32:57+09:00
Subject: xxd.rb

Here's a Ruby implementation of the xxd command that ships with vim. While not
a complete reimplementation it does perform the most important functions, i.e.
creating a text dump from a file and recreating a file from a text dump.

Suggestions for improvement most welcome.

#!/usr/bin/env ruby

# 2002-01-22 josb

# 0000000: 7f45 4c46 0101 0109 0000 0000 0000 0000  .ELF............

class Fixnum
	def even?
		self % 2 == 0
	end
end

n = 16
pat = /^[\da-f]{7}:(( [\da-f]{4}){1,8})/

def printable(c)
	case c
		when 0..037, 0177..0377 then "."
		else c.chr
	end
end

revert = nil
while ARGV[0] =~ /^-/
	case ARGV[0]
		when "-r"
			revert = 1
	end
	ARGV.shift
end

def printline(n,c,chars)
	line, i = "", 0
	line = chars.map {|ch| i += 1; sprintf "%02x%s", ch, i.even? ? ' ' : '' }
	text = chars.map {|ch| printable(ch) }
	printf "%07x: %-40s %-#{n}s\n", c - c % n, line, text
end

if revert
	$stdout.binmode # when running under DOS/Windows
	while line = gets
		if m = pat.match(line)
			print m[1].split(' ').map {|h| h.hex}.pack("n*")
		end
	end
else
	File::open(ARGV.shift) {|f|
		c = 0
		while ch = f.getc
			chars = [] if c % n == 0
			chars << ch
			c += 1
			printline(n, c - n, chars) if c % n == 0
		end
		# Print remaining bytes
		printline(n, c, chars) unless chars.empty?
	}
end

exit

-- 
Jos Backus                 _/  _/_/_/        Santa Clara, CA
                          _/  _/   _/
                         _/  _/_/_/             
                    _/  _/  _/    _/
josb@cncdsl.com     _/_/   _/_/_/            use Std::Disclaimer;