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using Plum::BinaryString
module Plum
module HPACK
module Huffman
extend self
# Static-Huffman-encodes the specified String.
def encode(bytestr)
ret = []
remain = 0
bytestr.each_byte do |b|
val, len = HUFFMAN_TABLE[b]
l = len - remain
ret[-1] |= val >> l if ret.size > 0
while l > 0
ret << ((val >> (l - 8)) & 0xff)
l -= 8
end
remain = -l % 8
end
ret[-1] |= (1 << remain) - 1 if remain > 0
ret.pack("C*")
end
# Static-Huffman-decodes the specified String.
def decode(encoded)
bits = encoded.unpack("B*")[0]
buf = ""
outl = []
while (n = bits.byteshift(1)).bytesize > 0
if c = HUFFMAN_DECODE_TABLE[buf << n]
buf = ""
outl << c
end
end
if buf.bytesize > 7
raise HPACKError.new("huffman: padding is too large (> 7 bits)")
elsif buf != "1" * buf.bytesize
raise HPACKError.new("huffman: unknown suffix: #{buf}")
else
outl.pack("C*")
end
end
end
end
end
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