Class: Hokusai::Util::PieceTable

Inherits:
Object
  • Object
show all
Defined in:
ui/src/hokusai/util/piece_table.rb

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(buffer = "") ⇒ PieceTable

Returns a new instance of PieceTable.



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# File 'ui/src/hokusai/util/piece_table.rb', line 8

def initialize(buffer = "")
  @pieces = [[:original, 0, buffer.size]]
  @buffer_add = ""
  @buffer = buffer
  @last_piece_index = nil
end

Instance Attribute Details

#buffer ⇒ Object

Returns the value of attribute buffer.



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# File 'ui/src/hokusai/util/piece_table.rb', line 5

def buffer
  @buffer
end

#buffer_add ⇒ Object

Returns the value of attribute buffer_add.



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# File 'ui/src/hokusai/util/piece_table.rb', line 5

def buffer_add
  @buffer_add
end

#last_piece_index ⇒ Object

Returns the value of attribute last_piece_index.



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# File 'ui/src/hokusai/util/piece_table.rb', line 5

def last_piece_index
  @last_piece_index
end

#pieces ⇒ Object (readonly)

Returns the value of attribute pieces.



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# File 'ui/src/hokusai/util/piece_table.rb', line 6

def pieces
  @pieces
end

Instance Method Details

#delete(offset, count) ⇒ Object 



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# File 'ui/src/hokusai/util/piece_table.rb', line 54

def delete(offset, count)
  piece_at_buffer_offset(offset) do |(piece_left, index_left, remainder_left)|
    piece_at_buffer_offset(offset + count) do |(piece_right, index_right, remainder_right)|
      if index_left == index_right
        if remainder_left == piece_left[1]
          pieces[index_left] = [piece_left[0], piece_left[1] + count, piece_left[2] - count]

          return
        elsif remainder_right == piece_left[1] + piece_left[2]
          pieces[index_left] = [piece_left[0], piece_left[1], piece_left[2] - count]
          
          return
        end
      end
  
      new_pieces = []
      left = [piece_left[0], piece_left[1], remainder_left - piece_left[1]]
      left_condition = (remainder_left - piece_left[1] > 0)
      right = [piece_right[0], remainder_right, piece_right[2] - (remainder_right - piece_right[1])]
      right_condition =  (piece_right[2] - (remainder_right - piece_right[1]) > 0)

      if !left_condition && !right_condition
        new_pieces << left
      end
      
      if left_condition
        new_pieces << left
      end

      if right_condition
        new_pieces << right
      end

      self.pieces[index_left..index_right] = new_pieces
      self.last_piece_index = nil
    end
  end
end

#insert(text, offset = buffer.size - 1) ⇒ Object 



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# File 'ui/src/hokusai/util/piece_table.rb', line 36

def insert(text, offset = buffer.size - 1)
  return nil if text.size.zero?

  piece_at_buffer_offset(offset) do |(piece, index, remainder)|
    which, start, size = piece
    length = remainder - start
    
    new_pieces = []
    new_pieces << [which, start, length] if length > 0
    new_pieces << [:add, buffer_add.size, text.size]
    new_pieces << [which, length + start, size - length] if size - length > 0
  
    self.last_piece_index = index + 1
    self.pieces[index..index] = new_pieces
    self.buffer_add += text
  end
end

#to_s ⇒ Object 



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# File 'ui/src/hokusai/util/piece_table.rb', line 15

def to_s
  io = StringIO.open do |io|
    pieces.each do |(which, start, size)|
      case which
      when :original
        io.write buffer[start, size]
      else
        if buffer_add[start, size].nil?
          raise Hokusai::Error.new("#{which} Bad: #{start} #{size}")
        end

        io.write buffer_add[start, size]
      end
    end

    io.string
  end

  io
end