Class: ReiserFS::FileData

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

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(dirEntry, superblock) ⇒ FileData

Initialization



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

def initialize(dirEntry, superblock)
  raise "Nil dirEntry object" if dirEntry.nil?
  raise "Nil superblock"      if superblock.nil?

  @sb   = superblock
  @de   = dirEntry
  @key  = @de.key
  @len  = @de.length
  @blocks = []

  # puts "Key=#{Utils.dumpKey(@key)} datalen=#{@len}"

  @sb.getLeafNodes(@key).each do |leaf|
    leaf.getItemHeaders(@key).each do |ih|
      next if Utils.typeIsStat?(leaf.getItemType(ih))
      raise "Directory Node when FileData expected" if Utils.typeIsDirectory?(leaf.getItemType(ih))

      if Utils.typeIsDirect?(leaf.getItemType(ih))
        @blocks << {:blockNum => leaf.blockNum, :offset => ih['location'], :length => ih['length'], :blockObj => leaf}
      end

      if Utils.typeIsIndirect?(leaf.getItemType(ih))
        leaf.getItem(ih).unpack("V*").each do |blockNum|
          @blocks << {:blockNum => blockNum, :offset => 0, :length => @sb.blockSize}
        end
      end
    end
  end

  @bpos  = []
  pos = 0
  @blocks.each do |b|
    @bpos << pos
    pos += b[:length]
  end

  @blen  = @blocks[0][:length]

  #      @blocks.each { |b| puts "Block(#{b['blockNum']}): len=#{b['length']} offset=#{b['offset']}"   }

  rewind
end

Instance Attribute Details

#pos ⇒ Object (readonly)

Returns the value of attribute pos.



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

def pos
  @pos
end

Instance Method Details

#findIndex(pos) ⇒ Object 



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# File 'lib/fs/ReiserFS/file_data.rb', line 51

def findIndex(pos)
  index = pos / @blen
  index -= 1 while                    @bpos[index] > pos
  index += 1 while @bpos[index + 1] && (@bpos[index + 1] < pos)
  index
end

#read(bytes = @len) ⇒ Object 



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

def read(bytes = @len)
  return nil if @pos >= @len

  index = findIndex(@pos)
  out = ""

  while out.length < bytes
    b      = @blocks[index]
    pos    = @bpos[index]
    index += 1

    blockLength = b[:length]
    blockLength = (@len - pos) if (pos + blockLength) > @len

    # Do we have to start reading from an offset?
    byteOffset = (pos < @pos) ? (@pos - pos) : 0

    # Get the block with data
    b[:blockObj] = @sb.readBlock(b[:blockNum])  unless b.key?(:blockObj)
    blockObj = b[:blockObj]

    # Extract the data we need out of it
    blockOffset = b[:offset]
    out << blockObj.data[blockOffset + byteOffset, blockLength - byteOffset]
  end

  bytes = out.length if bytes > out.length
  @pos += bytes

  out[0, bytes]
end

#rewind ⇒ Object 



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# File 'lib/fs/ReiserFS/file_data.rb', line 58

def rewind
  @pos = 0
end

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



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# File 'lib/fs/ReiserFS/file_data.rb', line 62

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 @len - offset
         end
  @pos = 0    if @pos < 0
  @pos = @len if @pos > @len
  @pos
end

#write(buf, _len = buf.length) ⇒ Object 



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# File 'lib/fs/ReiserFS/file_data.rb', line 105

def write(buf, _len = buf.length)
  raise "Write functionality is not yet supported on ReiserFS."
end