Module: Biryani::HPACK::Huffman

Defined in:
lib/biryani/hpack/huffman.rb

Overview

rubocop: disable Metrics/ModuleLength

Class Method Summary collapse

Class Method Details

.decode(io, cursor, length) ⇒ String

Parameters:

Returns:

Raises:

  • (HuffmanDecodeError) 


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# File 'lib/biryani/hpack/huffman.rb', line 553

def self.decode(io, cursor, length)
  res = ''.b
  bits = 0
  bits_len = 0
  bytes = io.get_values([:U8] * length, cursor)
  (length * 8).times do |i|
    bits_len += 1
    bits += 1 if (bytes[i / 8] & (1 << 7 - (i % 8))).positive?
    raise Error::HuffmanDecodeError if bits == EOS

    if (chr = DECODE_TABLE[[bits, bits_len]])
      res << chr
      bits = 0
      bits_len = 0
    else
      bits <<= 1
    end
  end
  raise Error::HuffmanDecodeError if bits_len.positive? && bits != (2 << bits_len) - 2 || bits_len >= 8

  res
end

.encode(s) ⇒ String

Parameters:

Returns:



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# File 'lib/biryani/hpack/huffman.rb', line 533

def self.encode(s)
  bits = s.bytes.map { |sym| ENCODE_TABLE[sym] }

  acc = IO::Buffer.new(bits.sum(&:bytesize))
  offset = 0
  bits.each do |s|
    acc.set_string(s, offset)
    offset += s.bytesize
  end

  [acc.get_string.ljust((acc.size + 7) & ~7, '1')].pack('B*')
end