Class: Ext3::FileData

Inherits:
Object
  • Object
show all
Defined in:
lib/fs/ext3/file_data.rb

Constant Summary collapse

SIZEOF_LONG = 
4
MAX_READ = 
4294967296
DEFAULT_BLOCK_SIZE = 
1024

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(inodeObj, superblock) ⇒ FileData

Initialization



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# File 'lib/fs/ext3/file_data.rb', line 14

def initialize(inodeObj, superblock)
  raise "Ext3::FileData.initialize: Nil inode object" if inodeObj.nil?
  raise "Ext3::FileData.initialize: Nil superblock"   if superblock.nil?

  @sb         = superblock
  @inodeObj   = inodeObj
  @blockSize  = @sb.blockSize
  @path = BlockPointersPath.new(@blockSize / SIZEOF_LONG)

  rewind
end

Instance Attribute Details

#pos ⇒ Object (readonly)

Returns the value of attribute pos.



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# File 'lib/fs/ext3/file_data.rb', line 11

def pos
  @pos
end

Instance Method Details

#read(bytes = @inodeObj.length) ⇒ Object 



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# File 'lib/fs/ext3/file_data.rb', line 41

def read(bytes = @inodeObj.length)
  raise "Ext3::FileData.read: Can't read 4G or more at a time (use a smaller read size)" if bytes >= MAX_READ
  return nil if @pos >= @inodeObj.length

  # Handle symbolic links.
  if @inodeObj.symlnk
    out = @inodeObj.symlnk[@pos...bytes]
    @pos += bytes
    return out
  end
  bytes = @inodeObj.length - @pos if @pos + bytes > @inodeObj.length

  # get data.
  startBlock, startByte, endBlock, endByte, nblocks = getStartBlock(@pos, bytes)
  out = getBlocks(startBlock, nblocks)
  @pos += bytes
  out[startByte, bytes]
end

#rewind ⇒ Object 



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# File 'lib/fs/ext3/file_data.rb', line 26

def rewind
  @pos = 0
end

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



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# File 'lib/fs/ext3/file_data.rb', line 30

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 @inodeObj.length - offset
         end
  @pos = 0                if @pos < 0
  @pos = @inodeObj.length if @pos > @inodeObj.length
  @pos
end

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



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# File 'lib/fs/ext3/file_data.rb', line 60

def write(buf, _len = buf.length)
  raise "Ext3::FileData.write: Write functionality is not yet supported on Ext3."

  # Commented out for now to avoid unreachable code
  #
  # @dirty = true
end