metasploit-framework/lib/metasm/misc/hexdiff.rb

#!/usr/bin/env ruby
#    This file is part of Metasm, the Ruby assembly manipulation suite
#    Copyright (C) 2006-2009 Yoann GUILLOT
#
#    Licence is LGPL, see LICENCE in the top-level directory



synclen = 6
ctxlen = 16

file1 = ('x'*ctxlen) + File.read(ARGV.shift)
file2 = ('x'*ctxlen) + File.read(ARGV.shift)

count1 = count2 = ctxlen

# prints the string in 80 cols
# with the first column filled with +pfx+
def show(pfx, str)
  loop do
    if str.length > 79
      len = 79 - str[0...79][/\S+$/].to_s.length
      len = 79 if len == 0
      puts pfx + str[0...len]
      str = str[len..-1]
    else
      puts pfx + str
      break
    end
  end
end

loop do
  w1 = file1[count1]
  w2 = file2[count2]
  break if not w1 and not w2
  if w1 == w2
    count1 += 1
    count2 += 1
  else
    diff1 = diff2 = nil
    catch(:resynced) {
    1000.times { |depth|
      (-depth..depth).map { |d|
        if d == 0
          [depth, depth]
        elsif d < 0
          [depth, depth+d]
        elsif d > 0
          [depth-d, depth]
        end
      }.each { |dc1, dc2|
        next if !(0...synclen).all? { |i| file1[count1 + dc1 + i] == file2[count2 + dc2 + i] }

        puts "@#{(count1-ctxlen).to_s 16} #{(count2-ctxlen).to_s 16}"
        show ' ', file1[count1-ctxlen, ctxlen].inspect
        if dc1 > 0
          show '-', file1[count1, dc1].inspect
        end
        if dc2 > 0
          show '+', file2[count2, dc2].inspect
        end
        count1 += dc1
        count2 += dc2
        show ' ', file1[count1, ctxlen].inspect
        puts

        throw :resynced
      }
    }
    raise 'nomatch..'
    }
  end
end