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# frozen_string_literal: true
module Zip
class DecryptedIo # :nodoc:all
CHUNK_SIZE = 32_768
def initialize(io, decrypter, compressed_size)
@io = io
@decrypter = decrypter
@bytes_remaining = compressed_size
@buffer = +''
end
def read(length = nil, outbuf = +'')
return (length.nil? || length.zero? ? '' : nil) if eof?
while length.nil? || (@buffer.bytesize < length)
break if input_finished?
@buffer << produce_input
end
@decrypter.check_integrity!(@io) if input_finished?
outbuf.replace(@buffer.slice!(0...(length || @buffer.bytesize)))
end
private
def eof?
@buffer.empty? && input_finished?
end
def input_finished?
!@bytes_remaining.positive?
end
def produce_input
chunk_size = [@bytes_remaining, CHUNK_SIZE].min
return '' unless chunk_size.positive?
@bytes_remaining -= chunk_size
@decrypter.decrypt(@io.read(chunk_size))
end
end
end
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