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Class: Fiddle::CUnionEntity

Relationships & Source Files
Super Chains via Extension / Inclusion / Inheritance
Class Chain:
self, CStructEntity, Pointer, FFI::DataConverter
Instance Chain:
self, CStructEntity, ValueUtil, PackInfo, Pointer
Inherits: Fiddle::CStructEntity
Defined in: ext/fiddle/lib/fiddle/struct.rb

Overview

A pointer to a C union

Constant Summary

PackInfo - Included

ALIGN_MAP, PACK_MAP, SIZE_MAP

Class Method Summary

  • .size(types)

    Returns the size needed for the union with the given types.

CStructEntity - Inherited

.alignment,
.malloc

Allocates a C struct with the types provided.
.new

Wraps the C pointer addr as a C struct with the given types.
.size

Returns the offset for the packed sizes for the given types.

Pointer - Inherited

.[]

call-seq:
.from_native, .malloc,
.new

Create a new pointer to address with an optional .size and freefunc.
.read

Or read the memory at address address with length len and return a string with that memory.
.to_native,
.to_ptr

Alias for Pointer.[].
.write

Write bytes in str to the location pointed to by address.

Instance Attribute Summary

Pointer - Inherited

#ffi_ptr,
#free

Get the free function for this pointer.
#free=

Set the free function for this pointer to function in the given Function.
#freed?

Returns if the free function for this pointer has been called.
#null?

Returns true if this is a null pointer.
#size

Get the size of this pointer.
#size=

Set the size of this pointer to .size

Instance Method Summary

  • #set_ctypes(types)

    Calculate the necessary offset and for each union member with the given types

CStructEntity - Inherited

#+, #-,
#[]

Fetch struct member name if only one argument is specified.
#[]=

Set struct member name, to value val.
#assign_names

Set the names of the members in this C struct.
#set_ctypes

Calculates the offsets and sizes for the given types in the struct.
#to_s

ValueUtil - Included

#signed_value, #unsigned_value, #wrap_arg, #wrap_args

PackInfo - Included

#align

Pointer - Inherited

#+

Returns a new pointer instance that has been advanced n bytes.
#+@

Returns a new Pointer instance that is a dereferenced pointer for this pointer.
#-

Returns a new pointer instance that has been moved back n bytes.
#-@

Returns a new Pointer instance that is a reference pointer for this pointer.
#<=>

Returns -1 if less than, 0 if equal to, 1 if greater than other.
#==

Returns true if other wraps the same pointer, otherwise returns false.
#[]

Returns integer stored at index.
#[]=

Set the value at index to int.
#call_free

Call the free function for this pointer.
#eql?

Alias for Pointer#==.
#initialize,
#inspect

Returns a string formatted with an easily readable representation of the internal state of the pointer.
#ptr

Alias for Pointer#+@.
#ref

Alias for Pointer#-@.
#to_i

Returns the integer memory location of this pointer.
#to_int

Alias for Pointer#to_i.
#to_ptr,
#to_s

Returns the pointer contents as a string.
#to_str

Returns the pointer contents as a string.
#to_value

Cast this pointer to a ruby object.

Constructor Details

This class inherits a constructor from Fiddle::CStructEntity

Class Method Details

.size(types)

Returns the size needed for the union with the given types.

Fiddle::CUnionEntity.size(
  [ Fiddle::TYPE_DOUBLE,
    Fiddle::TYPE_INT,
    Fiddle::TYPE_CHAR,
    Fiddle::TYPE_VOIDP ]) #=> 8
[ GitHub ] 

  


# File 'ext/fiddle/lib/fiddle/struct.rb', line 542



def CUnionEntity.size(types)
  types.map { |type, count = 1|
    if type.respond_to?(:entity_class)
      type.size * count
    else
      PackInfo::SIZE_MAP[type] * count
    end
  }.max
end


  







Instance Method Details



  

    #set_ctypes(types)  
  



  

    

Calculate the necessary offset and for each union member with the given types


  



  [ GitHub ]


  

  


# File 'ext/fiddle/lib/fiddle/struct.rb', line 554



def set_ctypes(types)
  @ctypes = types
  @offset = Array.new(types.length, 0)
  @size   = self.class.size types
end