Contents

# frozen_string_literal: true

module MSSMT
  # Intermediate or root node within a MS-SMT.
  class BranchNode
    attr_reader :left, :right, :node_hash, :sum

    # Constructor
    # @param [MSSMT::LeafNode|MSSMT::BranchNode] left
    # @param [MSSMT::LeafNode|MSSMT::BranchNode] right
    # @raise [MSSMT::OverflowError]
    def initialize(left, right)
      if !left.is_a?(BranchNode) && !left.is_a?(LeafNode)
        raise ArgumentError, "left must be a branch or leaf node"
      end
      if !right.is_a?(BranchNode) && !right.is_a?(LeafNode)
        raise ArgumentError, "right must be a branch or leaf node"
      end

      @left = left
      @right = right
      @sum = left.sum + right.sum
      if @sum > Tree::MAX_SUM_VALUE
        raise OverflowError, "sum: #{sum} is overflow"
      end

      @node_hash =
        Digest::SHA256.digest(
          "#{left.node_hash}#{right.node_hash}#{[@sum].pack("Q>")}"
        )
    end

    # Check whether same branch|computed node or not.
    # @return [Boolean]
    def ==(other)
      return false unless [BranchNode, ComputedNode].include?(other.class)
      node_hash == other.node_hash && sum == other.sum
    end

    def inspect
      "left: #{left.node_hash.unpack1("H*")}, right: #{right.node_hash.unpack1("H*")}, sum: #{sum}"
    end
  end
end

Version data entries

2 entries across 2 versions & 1 rubygems

Version	Path
mssmt-0.4.2	lib/mssmt/branch_node.rb
mssmt-0.4.1	lib/mssmt/branch_node.rb