Class: Iso9660::FileData

Inherits:
Object
  • Object
show all
Defined in:
lib/fs/iso9660/file_data.rb

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(dirEntry, bootSector) ⇒ FileData

Initialization



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# File 'lib/fs/iso9660/file_data.rb', line 8

def initialize(dirEntry, bootSector)
  raise "Nil directory entry" if dirEntry.nil?
  raise "Nil boot sector" if bootSector.nil?

  @bs = bootSector
  @de = dirEntry
  @last_sect = @de.fileSize.divmod(@bs.sectorSize)
  @last_sect[0] += 1 if @last_sect[1] > 0
  @last_sect = @last_sect[0]
  rewind
end

Instance Attribute Details

#pos ⇒ Object (readonly)

Returns the value of attribute pos.



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# File 'lib/fs/iso9660/file_data.rb', line 5

def pos
  @pos
end

Instance Method Details

#getLSN(vsn) ⇒ Object 



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# File 'lib/fs/iso9660/file_data.rb', line 73

def getLSN(vsn)
  return -1 if vsn > @last_sect
  @de.fileStart + vsn
end

#getSector(vsn) ⇒ Object 



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# File 'lib/fs/iso9660/file_data.rb', line 67

def getSector(vsn)
  lsn = getLSN(vsn)
  raise "No logical sector for virtual sector #{vsn}." if lsn == -1
  @bs.getSectors(lsn, 1)
end

#read(bytes = @de.fileSize) ⇒ Object 



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# File 'lib/fs/iso9660/file_data.rb', line 35

def read(bytes = @de.fileSize)
  return nil if @pos >= @de.fileSize
  bytes = @de.fileSize - @pos if @pos + bytes > @de.fileSize

  # Get start & end locs.
  ss = @bs.sectorSize
  startSector, startOffset = @pos.divmod(ss)
  endSector, endOffset = (@pos + (bytes - 1)).divmod(ss)

  # Single sector.
  if startSector == endSector
    @pos += (endOffset - startOffset)
    return getSector(startSector)[startOffset..endOffset]
  end

  # Span sectors.
  out = MemoryBuffer.create(bytes)
  totalLen = 0
  (startSector..endSector).each do |sect|
    offset = 0; len = ss
    if sect == startSector
      offset = startOffset
      len -= offset
    end
    len -= (ss - (endOffset + 1)) if sect == endSector
    out[totalLen, len] = getSector(sect)[offset, len]
    totalLen += len
    @pos += len
  end
  out[0..totalLen]
end

#rewind ⇒ Object 



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# File 'lib/fs/iso9660/file_data.rb', line 20

def rewind
  @pos = 0
end

#seek(offset, method = IO::SEEK_SET) ⇒ Object 



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# File 'lib/fs/iso9660/file_data.rb', line 24

def seek(offset, method = IO::SEEK_SET)
  @pos = case method
         when IO::SEEK_SET then offset
         when IO::SEEK_CUR then @pos + offset
         when IO::SEEK_END then @de.length - offset
         end
  @pos = 0 if @pos < 0
  @pos = @de.fileSize if @pos > @de.fileSize
  @pos
end