Class: RubyVM::RJIT::CPointer::Union

Inherits:
Object
  • Object
show all
Defined in:
lib/ruby_vm/rjit/c_pointer.rb

Overview

Note: We’d like to avoid alphabetic method names to avoid a conflict with member methods. to_i is considered an exception.

Class Method Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(addr, sizeof, members) ⇒ Union

Returns a new instance of Union.

Parameters:

  • _name (String) —

    To be used when it starts defining a union pointer class

  • sizeof (Integer)
  • members (Hash{ Symbol => RubyVM::RJIT::CType::* }) 


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# File 'lib/ruby_vm/rjit/c_pointer.rb', line 107

def initialize(addr, sizeof, members)
  @addr = addr
  @sizeof = sizeof
  @members = members
end

Class Method Details

.define(sizeof, members) ⇒ Object

Parameters:



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# File 'lib/ruby_vm/rjit/c_pointer.rb', line 132

def self.define(sizeof, members)
  Class.new(self) do
    # Return the size of this type
    define_singleton_method(:sizeof) { sizeof }

    # Part of Struct's offsetof implementation
    define_singleton_method(:offsetof) do |field, *fields|
      member = members.fetch(field)
      offset = 0
      unless fields.empty?
        offset += member.offsetof(*fields)
      end
      offset
    end

    define_method(:initialize) do |addr|
      super(addr, sizeof, members)
    end

    members.each do |member, type|
      # Intelligent API that does automatic dereference
      define_method(member) do
        value = type.new(@addr)
        if value.respond_to?(:*)
          value = value.*
        end
        value
      end
    end
  end
end

Instance Method Details

#+(index) ⇒ Object

Move addr to access this pointer like an array

Raises:

  • (ArgumentError) 


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# File 'lib/ruby_vm/rjit/c_pointer.rb', line 119

def +(index)
  raise ArgumentError unless index.is_a?(Integer)
  self.class.new(@addr + index * @sizeof)
end

#-(union) ⇒ Object

Pointer diff

Raises:

  • (ArgumentError) 


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# File 'lib/ruby_vm/rjit/c_pointer.rb', line 125

def -(union)
  raise ArgumentError if self.class != union.class
  (@addr - union.instance_variable_get(:@addr)) / @sizeof
end

#to_i ⇒ Object

Get a raw address



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# File 'lib/ruby_vm/rjit/c_pointer.rb', line 114

def to_i
  @addr
end