class HMAC::Base

# File lib/hmac/hmac.rb, line 88
def Base.digest(key, text)
  begin
    hmac = self.new(key)
    hmac.update(text)
    hmac.digest
  ensure
    hmac.reset_key
  end
end

# File lib/hmac/hmac.rb, line 98
def Base.hexdigest(key, text)
  begin
    hmac = self.new(key)
    hmac.update(text)
    hmac.hexdigest
  ensure
    hmac.reset_key
  end
end

# File lib/hmac/hmac.rb, line 16
def initialize(algorithm, block_size, output_length, key)
  @algorithm = algorithm
  @block_size = block_size
  @output_length = output_length
  @status = STATUS_UNDEFINED
  @key_xor_ipad = ''
  @key_xor_opad = ''
  set_key(key) unless key.nil?
end

# File lib/hmac/hmac.rb, line 74
def digest
  check_status
  @md.digest
end

# File lib/hmac/hmac.rb, line 79
def hexdigest
  check_status
  @md.hexdigest
end

# File lib/hmac/hmac.rb, line 51
def reset_key
  @key_xor_ipad.gsub!(/./, '?')
  @key_xor_opad.gsub!(/./, '?')
  @key_xor_ipad[0..-1] = ''
  @key_xor_opad[0..-1] = ''
  @status = STATUS_UNDEFINED
end

# File lib/hmac/hmac.rb, line 35
def set_key(key)
  # If key is longer than the block size, apply hash function
  # to key and use the result as a real key.
  key = @algorithm.digest(key) if key.size > @block_size
  key_xor_ipad = "\x36" * @block_size
  key_xor_opad = "\x5C" * @block_size
  for i in 0 .. key.size - 1
    key_xor_ipad[i] ^= key[i]
    key_xor_opad[i] ^= key[i]
  end
  @key_xor_ipad = key_xor_ipad
  @key_xor_opad = key_xor_opad
  @md = @algorithm.new
  @status = STATUS_INITIALIZED
end

# File lib/hmac/hmac.rb, line 59
def update(text)
  check_status
  # perform inner H
  md = @algorithm.new
  md.update(@key_xor_ipad)
  md.update(text)
  str = md.digest
  # perform outer H
  md = @algorithm.new
  md.update(@key_xor_opad)
  md.update(str)
  @md = md
end

# File lib/hmac/hmac.rb, line 27
def check_status
  unless @status == STATUS_INITIALIZED
    raise RuntimeError,
      "The underlying hash algorithm has not yet been initialized."
  end
end