module Fiddle::CStructBuilder

Used to construct C classes (CUnion, CStruct, etc)

Fiddle::Importer#struct and Fiddle::Importer#union wrap this functionality in an easy-to-use manner.

Public Class Methods

create(klass, types, members) click to toggle source

Construct a new class given a C:

  • class klass (CUnion, CStruct, or other that provide an entity_class)

  • types (Fiddle::TYPE_INT, Fiddle::TYPE_SIZE_T, etc., see the C types constants)

  • corresponding members

Fiddle::Importer#struct and Fiddle::Importer#union wrap this functionality in an easy-to-use manner.

Example:

require 'fiddle/struct'
require 'fiddle/cparser'

include Fiddle::CParser

types, members = parse_struct_signature(['int i','char c'])

MyStruct = Fiddle::CStructBuilder.create(Fiddle::CUnion, types, members)

obj = MyStruct.allocate

# File ext/fiddle/lib/fiddle/struct.rb, line 50
    def create(klass, types, members)
      new_class = Class.new(klass){
        define_method(:initialize){|addr|
          @entity = klass.entity_class.new(addr, types)
          @entity.assign_names(members)
        }
        define_method(:to_ptr){ @entity }
        define_method(:to_i){ @entity.to_i }
        members.each{|name|
          define_method(name){ @entity[name] }
          define_method(name + "="){|val| @entity[name] = val }
        }
      }
      size = klass.entity_class.size(types)
      new_class.module_eval("        def new_class.size()
          #{size}
        end
        def new_class.malloc()
          addr = Fiddle.malloc(#{size})
          new(addr)
        end
", __FILE__, __LINE__+1)
      return new_class
    end

Private Instance Methods

create(klass, types, members) click to toggle source

Construct a new class given a C:

  • class klass (CUnion, CStruct, or other that provide an entity_class)

  • types (Fiddle::TYPE_INT, Fiddle::TYPE_SIZE_T, etc., see the C types constants)

  • corresponding members

Fiddle::Importer#struct and Fiddle::Importer#union wrap this functionality in an easy-to-use manner.

Example:

require 'fiddle/struct'
require 'fiddle/cparser'

include Fiddle::CParser

types, members = parse_struct_signature(['int i','char c'])

MyStruct = Fiddle::CStructBuilder.create(Fiddle::CUnion, types, members)

obj = MyStruct.allocate

# File ext/fiddle/lib/fiddle/struct.rb, line 50
    def create(klass, types, members)
      new_class = Class.new(klass){
        define_method(:initialize){|addr|
          @entity = klass.entity_class.new(addr, types)
          @entity.assign_names(members)
        }
        define_method(:to_ptr){ @entity }
        define_method(:to_i){ @entity.to_i }
        members.each{|name|
          define_method(name){ @entity[name] }
          define_method(name + "="){|val| @entity[name] = val }
        }
      }
      size = klass.entity_class.size(types)
      new_class.module_eval("        def new_class.size()
          #{size}
        end
        def new_class.malloc()
          addr = Fiddle.malloc(#{size})
          new(addr)
        end
", __FILE__, __LINE__+1)
      return new_class
    end