Class: SDL2::Struct

Inherits:
FFI::Struct
  • Object
show all
Extended by:
StructHelper
Defined in:
lib/sdl2.rb

Overview

FFI::Struct class with some useful additions.

Class Method Summary collapse

Instance Method Summary collapse

Methods included from StructHelper

member_readers, member_writers

Constructor Details

#initialize(*args, &block) ⇒ Struct

Allows creation and use within block, automatically freeing pointer after block.



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# File 'lib/sdl2.rb', line 56

def initialize(*args, &block)
  super(*args)
  if block_given?
    throw 'Release must be defined to use block' unless self.class.respond_to?(:release)
    yield self
    self.class.release(self.pointer)
  end
end

Class Method Details

.cast(something) ⇒ Object

Default cast handler



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# File 'lib/sdl2.rb', line 150

def self.cast(something)
  
  if something.kind_of? self
  
    return something
  
  elsif something.kind_of? Hash

    return self.create(something)

  elsif something.nil?
  
    return something #TODO: Assume NUL is ok?
  
  else
    
    raise "#{self} can't cast #{something.insepct}"
  
  end
end

.create(values = {}) ⇒ Object

Placeholder for Structs that need to initialize values.



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# File 'lib/sdl2.rb', line 66

def self.create(values = {})
  created = self.new
  created.update_members(values)
  created
end

.release(pointer) ⇒ Object

A default release scheme is defined, but should be redefined where appropriate.



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# File 'lib/sdl2.rb', line 73

def self.release(pointer)
  pointer.free
end

Instance Method Details

#==(other) ⇒ Object

Compare two structures by class and values. This will return true if compared to a “partial hash”, if all the keys the hash defines equal



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# File 'lib/sdl2.rb', line 98

def ==(other)
  if PrintDebug
    @@rec ||= -1
    @@rec += 1
    pad = "\t"*@@rec

    puts
    puts " #{pad}COMPARING #{self} to #{other}"
  end

  result = catch(:result) do
    unless self.class == other.class or other.kind_of? Hash
      puts "Class Mismatch" if PrintDebug
      throw :result, false
    end

    if (other.kind_of? Hash) and (other.keys - members).any?
      puts "Extra Keys: #{other.keys-members}"
      thorw :result, false
    end

    if (other.respond_to?:null?) and (self.null? or other.null?)
      unless self.null? and other.null?
        puts "AHHHAOne is null and the other is not" if PrintDebug
        throw :result, false
      end
    else
      fields = other.kind_of?(Hash) ? members & other.keys : members
      fields.each do |field|
        print "#{pad} #{field}:#{self[field].class} = " if PrintDebug

        unless self[field] == other[field]

          puts "NO MATCH: #{self[field].to_s} #{other[field].to_s}" if PrintDebug
          throw :result, false
        end
        puts "MATCH" if PrintDebug
      end
    end

    true # Everything passed.

  end
  if PrintDebug
    @@rec += -1
    puts
    puts "#{pad}RESULT = #{result}"
  end
  return result
end

#free ⇒ Object 



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# File 'lib/sdl2.rb', line 77

def free()
  self.pointer.free
end

#update_members(values) ⇒ Object

Set members to values contained within hash.



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# File 'lib/sdl2.rb', line 172

def update_members(values)
  if values.kind_of? Array
    raise "#{self} has less fields then #{values.inspect}" if values.count > members.count
    members.first(values.count).each_with_index do |field, idx|
      self[field] = values[idx]
    end

  elsif values.kind_of? Hash
    common = (self.members & values.keys)
    common.each do |field|
      self[field] = values[field]
    end
  else
    raise "#{self}#update_members unable to update from #{values.inspect}"
  end
end