Sha256: 565c2189c1991e8d0f0a5b398f73448b74fcaf528f64cfaebf7e4eefcf709626
Contents?: true
Size: 1.13 KB
Versions: 16
Compression:
Stored size: 1.13 KB
Contents
require 'zlib'
#coding: binary
module ZSteg
class Checker
module Zlib
MIN_UNPACKED_SIZE = 4
class Result < Struct.new(:data, :offset)
MAX_SHOW_SIZE = 100
def to_s
x = data
x=x[0,MAX_SHOW_SIZE] + "..." if x.size > MAX_SHOW_SIZE
"zlib: data=#{x.inspect.bright_red}, offset=#{offset}, size=#{data.size}"
end
end
# try to find zlib
# http://blog.w3challs.com/index.php?post/2012/03/25/NDH2k12-Prequals-We-are-looking-for-a-real-hacker-Wallpaper-image
# http://blog.w3challs.com/public/ndh2k12_prequalls/sp113.bmp
def self.check_data data
return unless idx = data.index(/\x78[\x9c\xda\x01]/n)
zi = ::Zlib::Inflate.new
x = zi.inflate data[idx..-1]
# decompress OK
return Result.new x, idx if x.size >= MIN_UNPACKED_SIZE
rescue ::Zlib::BufError
# tried to decompress, but got EOF - need more data
return Result.new x, idx
rescue ::Zlib::DataError, ::Zlib::NeedDict
# not a zlib
ensure
zi.close if zi && !zi.closed?
end
end # Zlib
end # Checker
end # ZSteg
Version data entries
16 entries across 16 versions & 1 rubygems