module ObjectFramework::HTTP2::HPACK::Huffman

# File lib/object_framework/http2/hpack.rb, line 53
def self.decode(bytes, limit: 32 * 1024)
  output, node, tail, tail_size = +"".b, TREE, 0, 0
  bytes.each_byte do |byte|
    7.downto(0) do |index|
      bit = (byte >> index) & 1
      node = node[bit] || raise(CompressionError)
      tail, tail_size = (tail << 1) | bit, tail_size + 1
      if (symbol = node[:symbol])
        raise CompressionError if symbol == 256 || output.bytesize >= limit
        output << symbol
        node, tail, tail_size = TREE, 0, 0
      end
    end
  end
  raise CompressionError if tail_size > 7 || tail != (1 << tail_size) - 1
  output
end

# File lib/object_framework/http2/hpack.rb, line 38
def self.encode(bytes)
  output, bits, length = +"".b, 0, 0
  bytes.each_byte do |byte|
    code, size = HUFFMAN_CODES.fetch(byte)
    bits, length = (bits << size) | code, length + size
    while length >= 8
      length -= 8
      output << ((bits >> length) & 255)
    end
    bits &= (1 << length) - 1
  end
  output << ((bits << (8 - length)) | ((1 << (8 - length)) - 1)) if length.positive?
  output
end