130 lines
2.8 KiB
Ruby
130 lines
2.8 KiB
Ruby
require_relative 'array'
|
|
require_relative 'network'
|
|
require_relative 'bytes'
|
|
|
|
class NetChunk
|
|
attr_reader :next, :data, :msg, :sys, :flags
|
|
@@sent_vital_chunks = 0
|
|
|
|
def initialize(data)
|
|
@next = nil
|
|
@flags = {}
|
|
@size = 0
|
|
parse_header(data[0..2])
|
|
chunk_end = CHUNK_HEADER_SIZE + @size
|
|
# puts "data[0]: " + str_hex(data[0])
|
|
@data = data[CHUNK_HEADER_SIZE...chunk_end]
|
|
@msg = @data[0].unpack("C*").first
|
|
@sys = @msg & 1 == 1 ? true : false
|
|
@msg >>= 1
|
|
@next = data[chunk_end..] if data.size > chunk_end
|
|
end
|
|
|
|
def self.reset
|
|
@@sent_vital_chunks = 0
|
|
end
|
|
|
|
def to_s
|
|
"NetChunk\n" +
|
|
" msg=#{msg} sys=#{sys}\n" +
|
|
" #{@flags}\n" +
|
|
" data: #{str_hex(data)}"
|
|
end
|
|
|
|
##
|
|
# Create int array ready to be send over the network
|
|
#
|
|
# Given the flags hash (vital/resend)
|
|
# the size
|
|
# the sequence number
|
|
#
|
|
# It will create a 3 byte chunk header
|
|
# represented as an Array of 3 integers
|
|
def self.create_vital_header(flags, size, seq = nil)
|
|
@@sent_vital_chunks += 1
|
|
if seq.nil?
|
|
seq = @@sent_vital_chunks
|
|
end
|
|
|
|
flag_bits = '00'
|
|
flag_bits[0] = flags[:resend] ? '1' : '0'
|
|
flag_bits[1] = flags[:vital] ? '1' : '0'
|
|
|
|
size_bits = size.to_s(2).rjust(12, '0')
|
|
# size_bits[0..5]
|
|
# size_bits[6..]
|
|
|
|
|
|
seq_bits = seq.to_s(2).rjust(10, '0')
|
|
# seq_bits[0..1]
|
|
# seq_bits[2..]
|
|
|
|
# The vital chunk header is 3 bytes
|
|
# containing flags, size and sequence
|
|
# in the following format
|
|
#
|
|
# f=flag
|
|
# s=size
|
|
# q=sequence
|
|
#
|
|
# ffss ssss qqss ssss qqqq qqqq
|
|
header_bits =
|
|
flag_bits +
|
|
size_bits[0..5] +
|
|
seq_bits[0..1] +
|
|
size_bits[6..] +
|
|
seq_bits[2..]
|
|
header_bits.chars.groups_of(8).map do |eigth_bits|
|
|
eigth_bits.join('').to_i(2)
|
|
end
|
|
end
|
|
|
|
def parse_header(data)
|
|
# flags
|
|
flags = data[0].unpack("B*").first
|
|
flags = flags[0..1]
|
|
@flags[:resend] = flags[0] == "1"
|
|
@flags[:vital] = flags[1] == "1"
|
|
|
|
# size
|
|
size = data[0..1].unpack("B*").first
|
|
size_bytes = size.chars.groups_of(8)
|
|
# trim first 2 bits of both bytes
|
|
# Size: 2 bytes (..00 0000 ..00 0010)
|
|
size_bytes.map! {|b| b[2..].join('') }
|
|
@size = size_bytes.join('').to_i(2)
|
|
|
|
# sequence number
|
|
# in da third byte but who needs seq?!
|
|
end
|
|
|
|
def flags_vital
|
|
@flags[:vital]
|
|
end
|
|
|
|
def flags_resend
|
|
@flags[:resend]
|
|
end
|
|
end
|
|
|
|
MAX_NUM_CHUNKS = 1024
|
|
|
|
class BigChungusTheChunkGetter
|
|
def self.get_chunks(data)
|
|
chunks = []
|
|
chunk = NetChunk.new(data)
|
|
chunks.push(chunk)
|
|
while chunk.next
|
|
chunk = NetChunk.new(chunk.next)
|
|
chunks.push(chunk)
|
|
if chunks.size > MAX_NUM_CHUNKS
|
|
# inf loop guard case
|
|
puts "Warning: abort due to max num chunks bein reached"
|
|
break
|
|
end
|
|
end
|
|
chunks
|
|
end
|
|
end
|
|
|