ronin-rb/ronin-asm

# frozen_string_literal: true
#
# ronin-code-asm - A Ruby DSL for crafting Assembly programs and shellcode.
#
# Copyright (c) 2007-2024 Hal Brodigan (postmodern.mod3 at gmail.com)
#
# ronin-code-asm is free software: you can redistribute it and/or modify
# it under the terms of the GNU Lesser General Public License as published
# by the Free Software Foundation, either version 3 of the License, or
# (at your option) any later version.
#
# ronin-code-asm is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU Lesser General Public License for more details.
#
# You should have received a copy of the GNU Lesser General Public License
# along with ronin-code-asm.  If not, see <https://www.gnu.org/licenses/>.
#

module Ronin
  module Code
    module ASM
      #
      # Represents an Immediate Data Operand.
      #
      # @see http://asm.sourceforge.net/articles/linasm.html#Prefixes
      #
      class ImmediateOperand < Struct.new(:value, :width)

        #
        # Initializes a new Immediate Operand.
        #
        # @param [Integer, nil] value
        #   The value.
        #
        # @param [nil, 1, 2, 4, 8] width
        #   The size in bytes of the value.
        #
        def initialize(value,width=nil)
          super(value.to_i,width)
        end

        #
        # The width of the immediate operand.
        #
        # @return [8, 4, 2, 1]
        #   The width.
        #
        def width
          super || case value
                   when (0x100000000..0xffffffffffffffff),
                        (-0x7fffffffffffffff..-0x800000000) then 8
                   when (0x10000..0xffffffff),
                        (-0x7fffffff..-0x80000)             then 4
                   when (0x100..0xffff), (-0x7fff..-0x80)   then 2
                   when (0..0xff), (-0x7f..0)               then 1
                   end
        end

        #
        # Converts the operand to an Integer.
        #
        # @return [Integer]
        #   The value.
        #
        def to_i
          self.value
        end

        #
        # Converts the operand to a String.
        #
        # @return [String]
        #   The value in String form.
        #
        def to_s
          self.value.to_s
        end

      end
    end
  end
end