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Class: FFI::Enum

Relationships & Source Files
Extension / Inclusion / Inheritance Descendants
Subclasses:
Bitmask
Super Chains via Extension / Inclusion / Inheritance
Instance Chain:
self, DataConverter
Inherits: Object
Defined in: lib/ffi/enum.rb

Overview

Represents a C enum.

For a C enum:

enum fruits {
  apple,
  banana,
  orange,
  pineapple
};

are defined this vocabulary:

  • a symbol is a word from the enumeration (ie. apple, by example);

  • a value is the value of a symbol in the enumeration (by example, apple has value 0 and banana 1).

Class Method Summary

Instance Attribute Summary

Instance Method Summary

DataConverter - Included

#from_native

Convert from a native type.
#native_type

Get native type.
#to_native

Convert to a native type.

Constructor Details

.new(info, tag = nil) ⇒ Enum .new(native_type, info, tag = nil) ⇒ Enum

[ GitHub ] 

  


# File 'lib/ffi/enum.rb', line 96



def initialize(*args)
  @native_type = args.first.kind_of?(FFI::Type) ? args.shift : Type::INT
  info, @tag = *args
  @kv_map = Hash.new
  unless info.nil?
    last_cst = nil
    value = 0
    info.each do |i|
      case i
      when Symbol
        raise ArgumentError, "duplicate enum key" if @kv_map.has_key?(i)
        @kv_map[i] = value
        last_cst = i
        value += 1
      when Integer
        @kv_map[last_cst] = i
        value = i+1
      end
    end
  end
  @vk_map = @kv_map.invert
end


  







Instance Attribute Details



  

    #native_type   (readonly)
  

  [ GitHub ]


  

  


# File 'lib/ffi/enum.rb', line 87



attr_reader :native_type


  








  

    #tag   (readonly)
  

  [ GitHub ]


  

  


# File 'lib/ffi/enum.rb', line 86



attr_reader :tag


  







Instance Method Details



  

    

      #[](query)  ⇒ Integer 
      #[](query)  ⇒ Symbol 
    

    Also known as: #find
  



  

    

Get a symbol or a value from the enum.


  





  


  [ GitHub ]


  

  


# File 'lib/ffi/enum.rb', line 133



def [](query)
  case query
  when Symbol
    @kv_map[query]
  when Integer
    @vk_map[query]
  end
end


  








  

    #find(query)  
  



  

    

Alias for #[].


  



  [ GitHub ]


  

  


# File 'lib/ffi/enum.rb', line 141



alias find []


  








  

    #from_native(val, ctx)  ⇒ Object 
  



  

    
  





  
Parameters:


    
  
  • 
    val
    
  
    • 



Returns:


    
  
  • 
    
    
    

    symbol name if it exists for val.
    

    
  
    • 





  [ GitHub ]


  

  


# File 'lib/ffi/enum.rb', line 167



def from_native(val, ctx)
  @vk_map[val] || val
end


  








  

    #symbol_map  ⇒ Hash 
    Also known as: #to_h, #to_hash
  



  

    

Get the symbol map.


  





  


  [ GitHub ]


  

  


# File 'lib/ffi/enum.rb', line 145



def symbol_map
  @kv_map
end


  








  

    #symbols  ⇒ Array 
  



  

    
  





  
Returns:


    
  
  • 
    (Array)
—    
    

    enum symbol names
    

    
  
    • 





  [ GitHub ]


  

  


# File 'lib/ffi/enum.rb', line 120



def symbols
  @kv_map.keys
end


  








  

    #to_h  
  



  

    

Alias for #symbol_map.


  



  [ GitHub ]


  

  


# File 'lib/ffi/enum.rb', line 149



alias to_h symbol_map


  








  

    #to_hash  
  



  

    

Alias for #symbol_map.


  



  [ GitHub ]


  

  


# File 'lib/ffi/enum.rb', line 150



alias to_hash symbol_map


  








  

    #to_native(val, ctx)  ⇒ Integer 
  



  

    
  





  
Parameters:


    
  
  • 
    val
    (Symbol, Integer, #to_int)
  
    • 
  
  • 
    ctx
    
—    
    

    unused
    

    
  
    • 



Returns:


    
  
  • 
    (Integer)
—    
    

    value of a enum symbol
    

    
  
    • 





  [ GitHub ]


  

  


# File 'lib/ffi/enum.rb', line 155



def to_native(val, ctx)
  @kv_map[val] || if val.is_a?(Integer)
    val
  elsif val.respond_to?(:to_int)
    val.to_int
  else
    raise ArgumentError, "invalid enum value, #{val.inspect}"
  end
end