(feature request) reading a size_t from a Pointer

[Burgestrand]

I am binding a method that takes a pointer to a :size_t, but I cannot currently find any read_size_t method on FFI::Pointer. It’d be nice to have one.

[Burgestrand]

I’ve added a temporary solution on my personal project:

module FFI
  class Pointer
    type = FFI.find_type(:size_t)
    type, _ = FFI::TypeDefs.find do |(name, t)|
      method_defined? "read_#{name}" if t == type
    end

    alias_method :read_size_t, "read_#{type}" if type
  end
end

I’m blissfully unaware about the implications of “size_t”, all I do remember is that it’s a peculiar little type. For now, my above code will do for me.

[ghost]

I wonder if this could be generalised into a read_type() method.
e.g.

class Pointer
  # FFI.find_type() will resolve :size_t down to e.g. Type::INT32, so map from that to the appropriate read/write type
  TYPE_METHOD_NAMES = {
    Type::INT32, :int,
    Type::INT64, :long_long,
    # etc, etc
  }
  def read_type(type)
    method_name = TYPE_METHOD_NAMES[FFI.find_type(type)]
    self.send(method_name)
  end
end

That will be a lot slower than an alias, but it avoids polluting the Pointer class with a gazillion read/write methods for each type alias.

[Burgestrand]

Aye; one just has to remember to pass the arguments along as well.

[ghost]

Closing all feature-request issues