Class: LinkedList

Inherits:
Object show all
Includes:
Enumerable
Defined in:
lib/gamebox/lib/linked_list.rb

Defined Under Namespace

Classes: ListElem

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(enum = nil) ⇒ LinkedList

Returns a new instance of LinkedList.



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# File 'lib/gamebox/lib/linked_list.rb', line 7

def initialize(enum = nil)
  @head = @tail = ListElem.new
  @head.next = @head
  @head.prev = @head

  append enum unless enum.nil?
end

Instance Attribute Details

#head ⇒ Object

Returns the value of attribute head.



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# File 'lib/gamebox/lib/linked_list.rb', line 5

def head
  @head
end

#tail ⇒ Object

Returns the value of attribute tail.



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# File 'lib/gamebox/lib/linked_list.rb', line 5

def tail
  @tail
end

Instance Method Details

#append(e) ⇒ Object Also known as: << 



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# File 'lib/gamebox/lib/linked_list.rb', line 53

def append(e)
#    puts "appending #{e[0][0]},#{e[0][1]}"
  tmp = ListElem.new
  tmp.obj = e
  tmp.prev = @tail.prev
  tmp.next = @tail
  tmp.prev.next = tmp
  tmp.next.prev = tmp
#    puts to_s
  self
end

#each ⇒ Object 



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# File 'lib/gamebox/lib/linked_list.rb', line 98

def each
  i = @head.next

  while @tail != i
    yield i.obj
    i = i.next
  end
end

#each_element ⇒ Object 



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# File 'lib/gamebox/lib/linked_list.rb', line 107

def each_element
  i = @head.next

  while @tail != i
    yield i
    i = i.next
  end
end

#empty? ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/gamebox/lib/linked_list.rb', line 94

def empty?()
  @tail.prev == @head
end

#place(new_obj, location, elem) ⇒ Object 



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# File 'lib/gamebox/lib/linked_list.rb', line 33

def place(new_obj, location, elem)
#    puts "placing #{new_obj[0][0]},#{new_obj[0][1]} #{location} #{elem.obj[0][0]},#{elem.obj[0][1]}"
  tmp = ListElem.new
  tmp.obj = new_obj
  case location
  when :before
    tmp.next = elem
    tmp.prev = elem.prev
    elem.prev.next = tmp
    elem.prev = tmp
  when :after
    tmp.prev = elem
    tmp.next = elem.next
    elem.next.prev = tmp
    elem.next = tmp
  end
#    puts to_s
  tmp
end

#prepend(e) ⇒ Object Also known as: >> 



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# File 'lib/gamebox/lib/linked_list.rb', line 66

def prepend(e)
  tmp = ListElem.new
  tmp.obj = e
  tmp.prev = @head
  tmp.next = @head.next
  tmp.prev.next = tmp
  tmp.next.prev = tmp
  self
end

#remove(e) ⇒ Object Also known as: -

only removed the first instance of e



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# File 'lib/gamebox/lib/linked_list.rb', line 78

def remove(e)
  i = @head.next

  while @tail != i
    if i.obj == e
      # remove it
      i.prev.next = i.next
      i.next.prev = i.prev
      return i.obj
    end
    i = i.next
  end
  i
end

#shift ⇒ Object

pop off the first item



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# File 'lib/gamebox/lib/linked_list.rb', line 16

def shift
  tmp = @head.next
  @head.next = tmp.next
  tmp.next.prev = @head
  #puts "SHIFTING [#{tmp.obj.x},#{tmp.obj.y}]"
#    puts to_s
  return tmp.obj
end

#size ⇒ Object 



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# File 'lib/gamebox/lib/linked_list.rb', line 128

def size
  size = 0
  i = @head.next
  while @tail != i
    i = i.next
    size += 1
  end
  size
end

#to_s ⇒ Object 



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# File 'lib/gamebox/lib/linked_list.rb', line 116

def to_s
  str = "LinkedList #{self.object_id} ["
  i = @head.next

  while @tail != i
    str += "#{i.obj[0]}-#{i.obj[1]},"
    i = i.next
  end
  str  += "]"
  str
end

#unshift ⇒ Object

pop off the last item



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# File 'lib/gamebox/lib/linked_list.rb', line 26

def unshift
  tmp = @tail.prev
  @tail.prev = @tail.prev.prev
  @tail.next = @tail
  return tmp.obj
end