Module: Biryani::HPACK::Integer

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

Class Method Summary collapse

Class Method Details

.decode(io, n, cursor) ⇒ Integer

Parameters:

Returns:



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# File 'lib/biryani/hpack/integer.rb', line 49

def self.decode(io, n, cursor)
  limit = (1 << n) - 1
  h = io.get_value(:U8, cursor)
  return [h & limit, cursor + 1] if (h & limit) != limit

  res = limit
  c = cursor + 1
  i = 0
  loop do
    byte = io.get_value(:U8, c + i)
    res += (byte & 127) * 2**(i * 7)

    break if (byte & 128).zero?

    i += 1
  end

  [res, c + i + 1]
end

.encode(i, n, mask) ⇒ Array

if I < 2^N - 1, encode I on N bits else

encode (2^N - 1) on N bits
I = I - (2^N - 1)
while I >= 128
     encode (I % 128 + 128) on 8 bits
     I = I / 128
encode I on 8 bits

decode I from the next N bits if I < 2^N - 1, return I else

M = 0
repeat
    B = next octet
    I = I + (B & 127) * 2^M
    M = M + 7
while B & 128 == 128
return I

datatracker.ietf.org/doc/html/rfc7541#section-5.1

Parameters:

Returns:

  • (Array) 


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# File 'lib/biryani/hpack/integer.rb', line 29

def self.encode(i, n, mask)
  limit = (1 << n) - 1
  return [i | mask].pack('C*') if i < limit

  bytes = [limit | mask]
  i -= limit
  while i > 128
    bytes << i % 128 + 128
    i /= 128
  end
  bytes << i
  bytes.pack('C*')
end