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