Class: MppReader::Cfbf::Header

Inherits:
Object
  • Object
show all
Defined in:
lib/mpp_reader/cfbf/header.rb

Constant Summary collapse

SIGNATURE = 
"\xD0\xCF\x11\xE0\xA1\xB1\x1A\xE1".b.freeze

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(bytes) ⇒ Header

Returns a new instance of Header.



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# File 'lib/mpp_reader/cfbf/header.rb', line 19

def initialize(bytes)
  unless bytes && bytes.bytesize >= 512 && bytes.byteslice(0, 8) == SIGNATURE
    raise InvalidFormatError, "not an OLE2 compound file (bad signature)"
  end
  sector_shift = bytes.byteslice(30, 2).unpack1("v")
  mini_shift   = bytes.byteslice(32, 2).unpack1("v")
  unless sector_shift == 9 || sector_shift == 12
    raise InvalidFormatError, "invalid sector shift #{sector_shift} (must be 9 or 12)"
  end
  unless mini_shift == 6
    raise InvalidFormatError, "invalid mini sector shift #{mini_shift} (must be 6)"
  end
  @sector_size = 1 << sector_shift
  @mini_sector_size = 1 << mini_shift
  @num_fat_sectors, @first_dir_sector, _txn_sig, @mini_stream_cutoff,
    @first_minifat_sector, @num_minifat_sectors,
    @first_difat_sector, @num_difat_sectors = bytes.byteslice(44, 32).unpack("V8")
  @difat_head = bytes.byteslice(76, 436).unpack("V109")
end

Instance Attribute Details

#difat_head ⇒ Object (readonly)

Returns the value of attribute difat_head.



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# File 'lib/mpp_reader/cfbf/header.rb', line 14

def difat_head
  @difat_head
end

#first_difat_sector ⇒ Object (readonly)

Returns the value of attribute first_difat_sector.



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# File 'lib/mpp_reader/cfbf/header.rb', line 14

def first_difat_sector
  @first_difat_sector
end

#first_dir_sector ⇒ Object (readonly)

Returns the value of attribute first_dir_sector.



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# File 'lib/mpp_reader/cfbf/header.rb', line 14

def first_dir_sector
  @first_dir_sector
end

#first_minifat_sector ⇒ Object (readonly)

Returns the value of attribute first_minifat_sector.



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# File 'lib/mpp_reader/cfbf/header.rb', line 14

def first_minifat_sector
  @first_minifat_sector
end

#mini_sector_size ⇒ Object (readonly)

Returns the value of attribute mini_sector_size.



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# File 'lib/mpp_reader/cfbf/header.rb', line 14

def mini_sector_size
  @mini_sector_size
end

#mini_stream_cutoff ⇒ Object (readonly)

Returns the value of attribute mini_stream_cutoff.



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# File 'lib/mpp_reader/cfbf/header.rb', line 14

def mini_stream_cutoff
  @mini_stream_cutoff
end

#num_difat_sectors ⇒ Object (readonly)

Returns the value of attribute num_difat_sectors.



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# File 'lib/mpp_reader/cfbf/header.rb', line 14

def num_difat_sectors
  @num_difat_sectors
end

#num_fat_sectors ⇒ Object (readonly)

Returns the value of attribute num_fat_sectors.



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# File 'lib/mpp_reader/cfbf/header.rb', line 14

def num_fat_sectors
  @num_fat_sectors
end

#num_minifat_sectors ⇒ Object (readonly)

Returns the value of attribute num_minifat_sectors.



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# File 'lib/mpp_reader/cfbf/header.rb', line 14

def num_minifat_sectors
  @num_minifat_sectors
end

#sector_size ⇒ Object (readonly)

Returns the value of attribute sector_size.



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# File 'lib/mpp_reader/cfbf/header.rb', line 14

def sector_size
  @sector_size
end