require 'digest'

# s: String, bit: nummer
def flipBit(s, bit)
    # Kopie von s
    s = String.new(s)
    byte = bit/8;
    bit = bit%8;
    s.setbyte(byte,
      s.getbyte(byte)^(1 << bit))
    return s
end

# s1,s2: Zwei gleich lange Strings
def count_bit_diff(s1,s2)
    diff = 0
    s1.size.times{|i|
      xor = s1.getbyte(i)^s2.getbyte(i)
      # Ganzzahl: 1 Byte
      8.times{|bit|
        diff+=1 if (xor & (1<<bit))!=0
      }
    }
    return diff
end

text = File.read("hashtest.rb")
hash_orig = Digest::SHA256.digest(text)
counters = Array.new(256,0)
(text.size*8).times{|bit|
    modif = flipBit(text, bit);
    hash_modif = Digest::SHA256.digest(modif)
    counters[count_bit_diff(hash_orig, hash_modif)]+=1
}

# Generate CSV-Output
counters.each_with_index{|c,i|
        puts "#{i};#{c}"
}