Module: NBTFile::ReadMethods

Includes:
CommonMethods, Tokens
Included in:
CompoundReaderState, ListReaderState, TopReaderState
Defined in:
lib/nbtfile.rb

Instance Method Summary collapse

Methods included from CommonMethods

#sign_bit

Instance Method Details

#read_byte(io) ⇒ Object 



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# File 'lib/nbtfile.rb', line 119

def read_byte(io)
  read_integer(io, 1)
end

#read_byte_array(io) ⇒ Object 



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# File 'lib/nbtfile.rb', line 150

def read_byte_array(io)
  length = read_int(io)
  value = read_raw(io, length)
  value._nbtfile_force_encoding("BINARY")
  value
end

#read_double(io) ⇒ Object 



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# File 'lib/nbtfile.rb', line 139

def read_double(io)
  read_raw(io, 8).unpack("G").first
end

#read_float(io) ⇒ Object 



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# File 'lib/nbtfile.rb', line 135

def read_float(io)
  read_raw(io, 4).unpack("g").first
end

#read_int(io) ⇒ Object 



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# File 'lib/nbtfile.rb', line 127

def read_int(io)
  read_integer(io, 4)
end

#read_integer(io, n_bytes) ⇒ Object 



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# File 'lib/nbtfile.rb', line 110

def read_integer(io, n_bytes)
  raw_value = read_raw(io, n_bytes)
  value = (0...n_bytes).reduce(0) do |accum, n|
    (accum << 8) | raw_value._nbtfile_getbyte(n)
  end
  value -= ((value & sign_bit(n_bytes)) << 1)
  value
end

#read_list_header(io) ⇒ Object 



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# File 'lib/nbtfile.rb', line 157

def read_list_header(io)
  list_type = read_type(io)
  list_length = read_int(io)
  [list_type, list_length]
end

#read_long(io) ⇒ Object 



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# File 'lib/nbtfile.rb', line 131

def read_long(io)
  read_integer(io, 8)
end

#read_raw(io, n_bytes) ⇒ Object

Raises:

  • (EOFError) 


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# File 'lib/nbtfile.rb', line 104

def read_raw(io, n_bytes)
  data = io.read(n_bytes)
  raise EOFError unless data and data.length == n_bytes
  data
end

#read_short(io) ⇒ Object 



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# File 'lib/nbtfile.rb', line 123

def read_short(io)
  read_integer(io, 2)
end

#read_string(io) ⇒ Object 



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# File 'lib/nbtfile.rb', line 143

def read_string(io)
  length = read_short(io)
  string = read_raw(io, length)
  string._nbtfile_force_encoding("UTF-8")
  string
end

#read_type(io) ⇒ Object 



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# File 'lib/nbtfile.rb', line 163

def read_type(io)
  byte = read_byte(io)
  begin
    TOKEN_CLASSES_BY_INDEX.fetch(byte)
  rescue IndexError
    raise RuntimeError, "Unexpected tag ordinal #{byte}"
  end
end

#read_value(io, type, name, state, cont) ⇒ Object 



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# File 'lib/nbtfile.rb', line 172

def read_value(io, type, name, state, cont)
  next_state = state

  case
  when type == TAG_End
    next_state = cont
    value = nil
  when type == TAG_Byte
    value = read_byte(io)
  when type == TAG_Short
    value = read_short(io)
  when type == TAG_Int
    value = read_int(io)
  when type == TAG_Long
    value = read_long(io)
  when type == TAG_Float
    value = read_float(io)
  when type == TAG_Double
    value = read_double(io)
  when type == TAG_Byte_Array
    value = read_byte_array(io)
  when type == TAG_String
    value = read_string(io)
  when type == TAG_List
    list_type, list_length = read_list_header(io)
    next_state = ListReaderState.new(state, list_type, list_length)
    value = list_type
  when type == TAG_Compound
    next_state = CompoundReaderState.new(state)
  end

  [next_state, type[name, value]]
end