teeworlds_network/lib/chunk.rb

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require_relative 'array'
require_relative 'network'
require_relative 'bytes'
class NetChunk
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attr_reader :next, :data, :msg, :sys, :flags
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@@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]
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@msg = @data[0].unpack1('C*')
@sys = @msg & 1 == 1
@msg >>= 1
@next = data[chunk_end..] if data.size > chunk_end
end
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def self.reset
@@sent_vital_chunks = 0
end
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def to_s
"NetChunk\n" +
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" msg=#{msg} sys=#{sys}\n" +
" #{@flags}\n" +
" data: #{str_hex(data)}"
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end
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##
# 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
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seq = @@sent_vital_chunks if seq.nil?
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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
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header_bits =
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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
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flags = data[0].unpack1('B*')
flags = flags[0..1]
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@flags[:resend] = flags[0] == '1'
@flags[:vital] = flags[1] == '1'
# size
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size = data[0..1].unpack1('B*')
size_bytes = size.chars.groups_of(8)
# trim first 2 bits of both bytes
# Size: 2 bytes (..00 0000 ..00 0010)
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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
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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)
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next unless chunks.size > MAX_NUM_CHUNKS
# inf loop guard case
puts 'Warning: abort due to max num chunks bein reached'
break
end
chunks
end
end