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# encoding: utf-8
# name_tree.rb : Implements NameTree for PDF
#
# Copyright November 2008, Jamis Buck. All Rights Reserved.
#
# This is free software. Please see the LICENSE and COPYING files for details.
#
module Prawn
module Core
module NameTree #:nodoc:
class Node #:nodoc:
attr_reader :children
attr_reader :limit
attr_reader :document
attr_accessor :parent
attr_accessor :ref
def initialize(document, limit, parent=nil)
@document = document
@children = []
@limit = limit
@parent = parent
@ref = nil
end
def empty?
children.empty?
end
def size
leaf? ? children.size : children.inject(0) { |sum, child| sum + child.size }
end
def leaf?
children.empty? || children.first.is_a?(Value)
end
def add(name, value)
self << Value.new(name, value)
end
def to_hash
hash = {}
hash[:Limits] = [least, greatest] if parent
if leaf?
hash[:Names] = children if leaf?
else
hash[:Kids] = children.map { |child| child.ref }
end
return hash
end
def least
if leaf?
children.first.name
else
children.first.least
end
end
def greatest
if leaf?
children.last.name
else
children.last.greatest
end
end
def <<(value)
if children.empty?
children << value
elsif leaf?
children.insert(insertion_point(value), value)
split! if children.length > limit
else
fit = children.detect { |child| child >= value }
fit = children.last unless fit
fit << value
end
value
end
def >=(value)
children.empty? || children.last >= value
end
def split!
if parent
parent.split(self)
else
left, right = new_node(self), new_node(self)
split_children(self, left, right)
children.replace([left, right])
end
end
# Returns a deep copy of this node, without copying expensive things
# like the ref to @document.
#
def deep_copy
node = dup
node.instance_variable_set("@children",
Marshal.load(Marshal.dump(children)))
node.instance_variable_set("@ref",
node.ref ? node.ref.deep_copy : nil)
node
end
protected
def split(node)
new_child = new_node(self)
split_children(node, node, new_child)
index = children.index(node)
children.insert(index+1, new_child)
split! if children.length > limit
end
private
def new_node(parent=nil)
node = Node.new(document, limit, parent)
node.ref = document.ref!(node)
return node
end
def split_children(node, left, right)
half = (node.limit+1)/2
left_children, right_children = node.children[0...half], node.children[half..-1]
left.children.replace(left_children)
right.children.replace(right_children)
unless node.leaf?
left_children.each { |child| child.parent = left }
right_children.each { |child| child.parent = right }
end
end
def insertion_point(value)
children.each_with_index do |child, index|
return index if child >= value
end
return children.length
end
end
class Value #:nodoc:
include Comparable
attr_reader :name
attr_reader :value
def initialize(name, value)
@name, @value = Prawn::Core::LiteralString.new(name), value
end
def <=>(leaf)
name <=> leaf.name
end
def inspect
"#<Value: #{name.inspect} : #{value.inspect}>"
end
def to_s
"#{name} : #{value}"
end
end
end
end
end
|
