Module: Cbor

Defined in:
lib/rbor.rb,
lib/rbor/streaming.rb

Overview

The Concise Binary Object Representation (CBOR) is a data format whose design goals include the possibility of extremely small code size, fairly small message size, and extensibility without the need for version negotiation (RFC8949). It is used in different protocols like the Client to Authenticator Protocol CTAP2 which is a essential part of FIDO2 authenticators/ Passkeys.

Class Method Summary collapse

Class Method Details

.cbor_streaming_read ⇒ Object 



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# File 'lib/rbor/streaming.rb', line 2

def self.cbor_streaming_read
  raw = [yield]
  case raw[0]
  when 0x18, 0x38, 0x58, 0x78, 0x98, 0xb8
    raw.append yield
  when 0x19, 0x39, 0x59, 0x79, 0x99, 0xb9
    2.times { raw.append yield } 
  when 0x1a, 0x3a, 0x5a, 0x7a, 0x9a, 0xba
    4.times { raw.append yield } 
  when 0x1b, 0x3b, 0x5b, 0x7b, 0x9b, 0xbb
    8.times { raw.append yield } 
  when 0xf4
    return false
  when 0xf5
    return true
  when 0xf6
    return nil
  end
  
  case raw[0]
  when 0x00..0x1b, 0x20..0x3b
    return raw.cbor_deserialize
  when 0x40..0x5b
    raw[0] &= 0x1f
    data = []
    len, rem = raw.cbor_deserialize
    len.times { data.append yield } 
    return String.new(data.pack('C*'), encoding: "BINARY")
  when 0x60..0x7b
    raw[0] &= 0x1f
    data = []
    len, rem = raw.cbor_deserialize
    len.times { data.append yield } 
    return String.new(data.pack('C*'), encoding: "UTF-8")
  when 0x80..0x9b
    raw[0] &= 0x1f
    data = []
    len, rem = raw.cbor_deserialize
    len.times do
      data.append cbor_streaming_read { yield }
    end
    return data
  when 0xa0..0xbb
    raw[0] &= 0x1f
    data = {}
    len, rem = raw.cbor_deserialize
    len.times do
      k = cbor_streaming_read { yield }
      v = cbor_streaming_read { yield }
      data[k] = v
    end
    return data
  else
    raise "unsupported data item"
  end
  
end