71 lines
2.7 KiB
Ruby
71 lines
2.7 KiB
Ruby
module Zip
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# Info-ZIP Extra for Zip64 size
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class ExtraField::Zip64 < ExtraField::Generic
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attr_accessor :original_size, :compressed_size, :relative_header_offset, :disk_start_number
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HEADER_ID = ['0100'].pack('H*')
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register_map
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def initialize(binstr = nil)
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# unparsed binary; we don't actually know what this contains
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# without looking for FFs in the associated file header
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# call parse after initializing with a binary string
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@content = nil
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@original_size = nil
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@compressed_size = nil
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@relative_header_offset = nil
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@disk_start_number = nil
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binstr && merge(binstr)
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end
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def ==(other)
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other.original_size == @original_size &&
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other.compressed_size == @compressed_size &&
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other.relative_header_offset == @relative_header_offset &&
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other.disk_start_number == @disk_start_number
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end
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def merge(binstr)
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return if binstr.empty?
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_, @content = initial_parse(binstr)
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end
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# pass the values from the base entry (if applicable)
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# wider values are only present in the extra field for base values set to all FFs
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# returns the final values for the four attributes (from the base or zip64 extra record)
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def parse(original_size, compressed_size, relative_header_offset = nil, disk_start_number = nil)
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@original_size = extract(8, 'Q<') if original_size == 0xFFFFFFFF
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@compressed_size = extract(8, 'Q<') if compressed_size == 0xFFFFFFFF
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@relative_header_offset = extract(8, 'Q<') if relative_header_offset && relative_header_offset == 0xFFFFFFFF
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@disk_start_number = extract(4, 'V') if disk_start_number && disk_start_number == 0xFFFF
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@content = nil
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[@original_size || original_size,
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@compressed_size || compressed_size,
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@relative_header_offset || relative_header_offset,
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@disk_start_number || disk_start_number]
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end
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def extract(size, format)
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@content.slice!(0, size).unpack1(format)
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end
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private :extract
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def pack_for_local
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# local header entries must contain original size and compressed size; other fields do not apply
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return '' unless @original_size && @compressed_size
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[@original_size, @compressed_size].pack('Q<Q<')
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end
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def pack_for_c_dir
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# central directory entries contain only fields that didn't fit in the main entry part
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packed = ''.force_encoding('BINARY')
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packed << [@original_size].pack('Q<') if @original_size
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packed << [@compressed_size].pack('Q<') if @compressed_size
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packed << [@relative_header_offset].pack('Q<') if @relative_header_offset
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packed << [@disk_start_number].pack('V') if @disk_start_number
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packed
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end
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end
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end
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