Method: Addressable::IDNA.punycode_decode

Defined in:: lib/addressable/idna/pure.rb,
lib/addressable/idna/native.rb
.punycode_decode(value) ⇒ `Object`

# File 'lib/addressable/idna/pure.rb', line 4549

def self.punycode_decode(punycode)
  input = []
  output = []

  if ACE_MAX_LENGTH * 2 < punycode.size
    raise PunycodeBigOutput, "Output would exceed the space provided."
  end
  punycode.each_byte do |c|
    unless c >= 0 && c <= 127
      raise PunycodeBadInput, "Input is invalid."
    end
    input.push(c)
  end

  input_length = input.length
  output_length = [UNICODE_MAX_LENGTH]

  # Initialize the state
  n = PUNYCODE_INITIAL_N

  out = i = 0
  max_out = output_length[0]
  bias = PUNYCODE_INITIAL_BIAS

  # Handle the basic code points:  Let b be the number of input code
  # points before the last delimiter, or 0 if there is none, then
  # copy the first b code points to the output.

  b = 0
  input_length.times do |j|
    b = j if punycode_delimiter?(input[j])
  end
  if b > max_out
    raise PunycodeBigOutput, "Output would exceed the space provided."
  end

  b.times do |j|
    unless punycode_basic?(input[j])
      raise PunycodeBadInput, "Input is invalid."
    end
    output[out] = input[j]
    out+=1
  end

  # Main decoding loop:  Start just after the last delimiter if any
  # basic code points were copied; start at the beginning otherwise.

  in_ = b > 0 ? b + 1 : 0
  while in_ < input_length

    # in_ is the index of the next character to be consumed, and
    # out is the number of code points in the output array.

    # Decode a generalized variable-length integer into delta,
    # which gets added to i.  The overflow checking is easier
    # if we increase i as we go, then subtract off its starting
    # value at the end to obtain delta.

    oldi = i; w = 1; k = PUNYCODE_BASE
    while true
      if in_ >= input_length
        raise PunycodeBadInput, "Input is invalid."
      end
      digit = punycode_decode_digit(input[in_])
      in_+=1
      if digit >= PUNYCODE_BASE
        raise PunycodeBadInput, "Input is invalid."
      end
      if digit > (PUNYCODE_MAXINT - i) / w
        raise PunycodeOverflow, "Input needs wider integers to process."
      end
      i += digit * w
      t = (
        if k <= bias
          PUNYCODE_TMIN
        elsif k >= bias + PUNYCODE_TMAX
          PUNYCODE_TMAX
        else
          k - bias
        end
      )
      break if digit < t
      if w > PUNYCODE_MAXINT / (PUNYCODE_BASE - t)
        raise PunycodeOverflow, "Input needs wider integers to process."
      end
      w *= PUNYCODE_BASE - t
      k += PUNYCODE_BASE
    end

    bias = punycode_adapt(i - oldi, out + 1, oldi == 0)

    # I was supposed to wrap around from out + 1 to 0,
    # incrementing n each time, so we'll fix that now:

    if i / (out + 1) > PUNYCODE_MAXINT - n
      raise PunycodeOverflow, "Input needs wider integers to process."
    end
    n += i / (out + 1)
    i %= out + 1

    # Insert n at position i of the output:

    # not needed for Punycode:
    # raise PUNYCODE_INVALID_INPUT if decode_digit(n) <= base
    if out >= max_out
      raise PunycodeBigOutput, "Output would exceed the space provided."
    end

    #memmove(output + i + 1, output + i, (out - i) * sizeof *output)
    output[i + 1, out - i] = output[i, out - i]
    output[i] = n
    i += 1

    out += 1
  end

  output_length[0] = out

  output.pack("U*")
end
Method: Addressable::IDNA.punycode_decode

.punycode_decode(value) ⇒ Object

.punycode_decode(value) ⇒ `Object`
