Class: Reader

Inherits:
Object
  • Object
show all
Defined in:
lib/surpass/document.rb

Constant Summary collapse

DIR_ENTRY_SIZE = 
128

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(file) ⇒ Reader

Returns a new instance of Reader.



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# File 'lib/surpass/document.rb', line 28

def initialize(file)
  @streams = {}
  
  file = File.open(file, 'rb') unless file.respond_to?(:read)
  doc = file.read
  @header, @data = doc[0...512], doc[512..-1]
  
  build_header
  build_msat
  build_sat
  build_directory
  build_short_sectors_data

  if @short_sectors_data.length > 0
    build_ssat
  else
    @ssat_start_sid = -2
    @total_ssat_sectors = 0
    @ssat = [-2]
  end

  @dir_entry_list[1..-1].each do |d|
    did, sz, name, t, c, did_left, did_right, did_root, dentry_start_sid, stream_size = d
    stream_data = ''
    if stream_size > 0
      if stream_size > @min_stream_size
        args = [@data, @sat, dentry_start_sid, @sect_size]
      else
        args = [@short_sectors_data, @ssat, dentry_start_sid, @short_sect_size]
      end
      stream_data = stream_data(*args)
    end
    # BAD IDEA: names may be equal. NEED use full paths...
    @streams[name] = stream_data if !name.length == 0
  end
end

Instance Attribute Details

#byte_order ⇒ Object

Returns the value of attribute byte_order.



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# File 'lib/surpass/document.rb', line 11

def byte_order
  @byte_order
end

#data ⇒ Object

Returns the value of attribute data.



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# File 'lib/surpass/document.rb', line 5

def data
  @data
end

#dir_entry_list ⇒ Object

Returns the value of attribute dir_entry_list.



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# File 'lib/surpass/document.rb', line 26

def dir_entry_list
  @dir_entry_list
end

#dir_start_sid ⇒ Object

Returns the value of attribute dir_start_sid.



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# File 'lib/surpass/document.rb', line 16

def dir_start_sid
  @dir_start_sid
end

#doc_magic ⇒ Object

Returns the value of attribute doc_magic.



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# File 'lib/surpass/document.rb', line 7

def doc_magic
  @doc_magic
end

#file_uid ⇒ Object

Returns the value of attribute file_uid.



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# File 'lib/surpass/document.rb', line 8

def file_uid
  @file_uid
end

#header ⇒ Object

Returns the value of attribute header.



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# File 'lib/surpass/document.rb', line 4

def header
  @header
end

#min_stream_size ⇒ Object

Returns the value of attribute min_stream_size.



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# File 'lib/surpass/document.rb', line 17

def min_stream_size
  @min_stream_size
end

#msat ⇒ Object

Returns the value of attribute msat.



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# File 'lib/surpass/document.rb', line 23

def msat
  @msat
end

#msat_start_sid ⇒ Object

Returns the value of attribute msat_start_sid.



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# File 'lib/surpass/document.rb', line 20

def msat_start_sid
  @msat_start_sid
end

#rev_num ⇒ Object

Returns the value of attribute rev_num.



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# File 'lib/surpass/document.rb', line 9

def rev_num
  @rev_num
end

#sat ⇒ Object

Returns the value of attribute sat.



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# File 'lib/surpass/document.rb', line 24

def sat
  @sat
end

#sect_size ⇒ Object

Returns the value of attribute sect_size.



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# File 'lib/surpass/document.rb', line 12

def sect_size
  @sect_size
end

#short_sect_size ⇒ Object

Returns the value of attribute short_sect_size.



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# File 'lib/surpass/document.rb', line 13

def short_sect_size
  @short_sect_size
end

#ssat ⇒ Object

Returns the value of attribute ssat.



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# File 'lib/surpass/document.rb', line 25

def ssat
  @ssat
end

#ssat_start_sid ⇒ Object

Returns the value of attribute ssat_start_sid.



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# File 'lib/surpass/document.rb', line 18

def ssat_start_sid
  @ssat_start_sid
end

#total_msat_sectors ⇒ Object

Returns the value of attribute total_msat_sectors.



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# File 'lib/surpass/document.rb', line 21

def total_msat_sectors
  @total_msat_sectors
end

#total_sat_sectors ⇒ Object

Returns the value of attribute total_sat_sectors.



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# File 'lib/surpass/document.rb', line 15

def total_sat_sectors
  @total_sat_sectors
end

#total_ssat_sectors ⇒ Object

Returns the value of attribute total_ssat_sectors.



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# File 'lib/surpass/document.rb', line 19

def total_ssat_sectors
  @total_ssat_sectors
end

#ver_num ⇒ Object

Returns the value of attribute ver_num.



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# File 'lib/surpass/document.rb', line 10

def ver_num
  @ver_num
end

Instance Method Details

#build_directory ⇒ Object 



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# File 'lib/surpass/document.rb', line 110

def build_directory
  dir_stream = stream_data(@data, @sat, @dir_start_sid, @sect_size)
  @dir_entry_list = []
  i = 0
  while i < dir_stream.length do
    dentry = dir_stream[i...(i+DIR_ENTRY_SIZE)]
    i += DIR_ENTRY_SIZE
    
    did = @dir_entry_list.length
    sz = dentry[64...66].unpack('C')[0]
    
    if sz > 0
      name = dentry[0...(sz-2)] # TODO unicode
    else
      name = ''
    end
    
    t = dentry[66...67].unpack('C')[0]
    c = dentry[67...68].unpack('C')[0]
    did_left = dentry[68...72].unpack('V')[0]
    did_right = dentry[72...76].unpack('V')[0]
    did_root = dentry[76...80].unpack('V')[0]
    dentry_start_sid = dentry[116...120].unpack('V')[0]
    stream_size = dentry[120...124].unpack('V')[0]
    
    @dir_entry_list << [did, sz, name, t, c, did_left, did_right, did_root, dentry_start_sid, stream_size]
  end
end

#build_header ⇒ Object 



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# File 'lib/surpass/document.rb', line 65

def build_header
  @doc_magic = @header[0...8]
  raise 'Not an OLE file.' unless @doc_magic === "\320\317\021\340\241\261\032\341"

  @file_uid              = @header[8...24]
  @rev_num               = @header[24...26]
  @ver_num               = @header[26...28]
  @byte_order            = @header[28...30]
  @log2_sect_size       = @header[30...32].unpack('v')[0]
  @log2_short_sect_size = @header[32...34].unpack('v')[0]
  @total_sat_sectors    = @header[44...48].unpack('V')[0]
  @dir_start_sid        = @header[48...52].unpack('V')[0]
  @min_stream_size      = @header[56...60].unpack('V')[0]
  @ssat_start_sid       = @header[60...64].unpack('V')[0]
  @total_ssat_sectors   = @header[64...68].unpack('V')[0]
  @msat_start_sid       = @header[68...72].unpack('V')[0]
  @total_msat_sectors   = @header[72...76].unpack('V')[0]

  @sect_size        = 1 << @log2_sect_size
  @short_sect_size  = 1 << @log2_short_sect_size
end

#build_msat ⇒ Object 



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# File 'lib/surpass/document.rb', line 87

def build_msat
  @msat = @header[76..-1].unpack('V109')
  next_sector = @msat_start_sid
  while next_sector > 0 do
    raise "not implemented"
    start = next_sector * @sect_size
    finish = (next_sector + 1) * @sect_size
    msat_sector = @data[start...finish]
    @msat << msat_sector
    next_sector = msat_sector[-1]
  end
end

#build_sat ⇒ Object 



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# File 'lib/surpass/document.rb', line 100

def build_sat
  sat_stream = @msat.collect {|i| i >= 0 ? @data[(i*@sect_size)...((i+1)*@sect_size)] : '' }.join
  @sat = sat_stream.unpack('V*')
end

#build_short_sectors_data ⇒ Object 



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# File 'lib/surpass/document.rb', line 139

def build_short_sectors_data
  did, sz, name, t, c, did_left, did_right, did_root, dentry_start_sid, stream_size = @dir_entry_list[0]
  raise unless t == 0x05 # Short-Stream Container Stream (SSCS) resides in Root Storage

  if stream_size == 0
    @short_sectors_data = ''
  else
    @short_sectors_data = stream_data(@data, @sat, dentry_start_sid, @sect_size)
  end
end

#build_ssat ⇒ Object 



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# File 'lib/surpass/document.rb', line 105

def build_ssat
  ssat_stream = stream_data(@data, @sat, @ssat_start_sid, @sect_size)
  @ssat = ssat_stream.unpack('V*')
end

#stream_data(data, sat, start_sid, sect_size) ⇒ Object 



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# File 'lib/surpass/document.rb', line 150

def stream_data(data, sat, start_sid, sect_size)
  sid = start_sid
  chunks = [[sid, sid]]
  stream_data = ''
  while sat[sid] >= 0 do
      next_in_chain = sat[sid]
      last_chunk_start, last_chunk_finish = chunks[-1]
      if next_in_chain == last_chunk_finish + 1
          chunks[-1] = last_chunk_start, next_in_chain
      else
          chunks << [next_in_chain, next_in_chain]
      end
      sid = next_in_chain
  end
  
  chunks.each do |s, f|
    stream_data += data[s*sect_size...(f+1)*sect_size]
  end
  stream_data
end