Class: Btree::Node
- Inherits:
-
Object
- Object
- Btree::Node
- Defined in:
- lib/btree/node.rb
Instance Method Summary collapse
- #add_child(node) ⇒ Object
- #children ⇒ Object
- #dump(level = 0) ⇒ Object
- #full? ⇒ Boolean
-
#initialize(degree) ⇒ Node
constructor
A new instance of Node.
- #insert(key, value) ⇒ Object
- #keys ⇒ Object
- #leaf? ⇒ Boolean
- #size ⇒ Object
- #split(child_idx) ⇒ Object
- #value_of(key) ⇒ Object
- #values ⇒ Object
- #values_of(range) ⇒ Object
Constructor Details
#initialize(degree) ⇒ Node
Returns a new instance of Node.
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# File 'lib/btree/node.rb', line 2 def initialize(degree) @degree = degree @keys = [] @children = [] end |
Instance Method Details
#add_child(node) ⇒ Object
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# File 'lib/btree/node.rb', line 21 def add_child(node) @children << node end |
#children ⇒ Object
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# File 'lib/btree/node.rb', line 25 def children @children.dup.freeze end |
#dump(level = 0) ⇒ Object
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# File 'lib/btree/node.rb', line 8 def dump(level = 0) @keys.each_with_index do |key, idx| puts "LEVEL: #{level} => #{key.first}: full? #{full?} leaf? #{leaf?} children: #{values.inspect}" if @children[idx] @children[idx].dump(level + 1) end end (@children[@keys.size..-1] || []).each do |c| c.dump(level+1) end nil end |
#full? ⇒ Boolean
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# File 'lib/btree/node.rb', line 37 def full? size >= 2 * @degree - 1 end |
#insert(key, value) ⇒ Object
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# File 'lib/btree/node.rb', line 91 def insert(key, value) i = size - 1 #puts "INSERTING #{key} INTO NODE: #{self.inspect}" if leaf? raise "Duplicate key" if @keys.any?{|(k,v)| k == key } #OPTIMIZE: This is inefficient while i >= 0 && @keys[i] && key < @keys[i].first @keys[i+1] = @keys[i] i -= 1 end @keys[i+1] = [key, value] else while i >= 0 && @keys[i] && key < @keys[i].first i -= 1 end #puts " -- INSERT KEY INDEX #{i}" if @children[i+1] && @children[i+1].full? split(i+1) if key > @keys[i+1].first i += 1 end end @children[i+1].insert(key, value) end end |
#keys ⇒ Object
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# File 'lib/btree/node.rb', line 29 def keys @keys.map(&:first).freeze end |
#leaf? ⇒ Boolean
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# File 'lib/btree/node.rb', line 41 def leaf? @children.length == 0 end |
#size ⇒ Object
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# File 'lib/btree/node.rb', line 45 def size @keys.size end |
#split(child_idx) ⇒ Object
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# File 'lib/btree/node.rb', line 116 def split(child_idx) raise "Invalid child index #{child_idx} in split, num_children = #{@children.size}" if child_idx < 0 || child_idx >= @children.size #puts "SPLIT1: #{self.inspect}" splitee = @children[child_idx] y = Btree::Node.new(@degree) z = Btree::Node.new(@degree) (@degree-1).times do |j| z._keys[j] = splitee._keys[j+@degree] y._keys[j] = splitee._keys[j] end if !splitee.leaf? @degree.times do |j| z._children[j] = splitee._children[j+@degree] y._children[j] = splitee._children[j] end end mid_val = splitee._keys[@degree-1] #puts "SPLIT2: #{self.inspect}" (@keys.size).downto(child_idx) do |j| @children[j+1] = @children[j] end @children[child_idx+1] = z @children[child_idx] = y #puts "SPLIT3: #{self.inspect}" (@keys.size - 1).downto(child_idx) do |j| @keys[j+1] = @keys[j] end #puts "SPLIT4: #{self.inspect}" @keys[child_idx] = mid_val #puts "SPLIT5: #{self.inspect}" end |
#value_of(key) ⇒ Object
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# File 'lib/btree/node.rb', line 68 def value_of(key) return values_of(key) if key.kind_of? Range i = 1 while i <= size && key > @keys[i-1].first i += 1 end #puts "Getting value of key #{key}, i = #{i}, keys = #{@keys.inspect}, leaf? #{leaf?}, numchildren: #{@children.size}" if i <= size && key == @keys[i-1].first #puts "Found key: #{key.inspect}" return @keys[i-1].last elsif leaf? #puts "We are a leaf, no more children, so val is nil" return nil else #puts "Looking into child #{i}" return @children[i-1].value_of(key) end end |
#values ⇒ Object
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# File 'lib/btree/node.rb', line 33 def values @keys.map(&:last).freeze end |
#values_of(range) ⇒ Object
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# File 'lib/btree/node.rb', line 49 def values_of(range) result = Array.new i = 1 while i <= size && range.end >= @keys[i-1].first if range.cover? @keys[i-1].first result << @keys[i-1].last child = @children[i-1].values_of(range) unless leaf? result += child if child end i += 1 end result end |