Class: Fiddle::CUnionEntity

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

Overview

A C union wrapper

.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`.

.[]	Get the underlying pointer for ruby object `val` and return it as a Pointer object.
.new	Create a new pointer to `address` with an optional .size and `freefunc`.
.to_ptr	Alias for Pointer.[].

#free	Get the free function for this pointer.
#free=	Set the free function for this pointer to `function` in the given Function.
#size	Get the size of this pointer.
#size=	Set the size of this pointer to .size
#null?	Returns `true` if this is a null pointer.

#set_ctypes(types)

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

#[]	Fetch struct member `name`
#[]=	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.

#+	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`.
#eql?	Alias for Pointer#==.
#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_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.

This class inherits a constructor from Fiddle::CStructEntity

Allocates a C union the types provided.

When the instance is garbage collected, the C function func is called.

[ GitHub ]

# File 'ext/fiddle/lib/fiddle/struct.rb', line 216


def CUnionEntity.malloc(types, func=nil)
  addr = Fiddle.malloc(CUnionEntity.size(types))
  CUnionEntity.new(addr, types, func)
end

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 228


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

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

[ GitHub ]

# File 'ext/fiddle/lib/fiddle/struct.rb', line 236


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