ffi · sparkchaser · Aug 27, 2015 · Aug 27, 2015 · Aug 28, 2015 · Aug 28, 2015
diff --git a/lib/ffi/struct.rb b/lib/ffi/struct.rb
@@ -33,6 +33,7 @@
 
 require 'ffi/platform'
 require 'ffi/struct_layout_builder'
+require 'json'
 
 module FFI
 
@@ -146,6 +147,102 @@ def to_ptr
       pointer
     end
 
+    # Recursively dump this structure's data as a Hash.
+    # @return [Hash] Hash containing member/data pairs for every member in the struct
+    #
+    # @example
+    #   z = Rect.new
+    #   z[:x] = 1
+    #   z[:y] = 2
+    #   z[:w] = 3
+    #   z[:h] = 4
+    #   z.to_h => {:h=>4, :w=>3, :x=>1, :y=>2}
+    def to_h
+      m_list = {}
+      members.collect do |m|
+        if self[m].is_a?(FFI::Struct)
+          m_list[m] = self[m].to_h
+        else
+          m_list[m] = self[m]
+        end
+      end
+      return m_list
+    end
+
+    # Recursively dump this structure's data as an Array.
+    # The array contains only the data, not the member names.
+    # @return [Array] array of data
+    #
+    # @note the order of data in the array always matches the
+    #   order of members given in #layout. 
+    #
+    # @example
+    #   z = Rect.new
+    #   z[:x] = 1
+    #   z[:y] = 2
+    #   z[:w] = 3
+    #   z[:h] = 4
+    #   z.to_a => [1,2,3,4]
+    def to_a
+      members.collect do |m|
+          if self[m].is_a?(FFI::Struct)
+              self[m].to_a
+          else
+              self[m]
+          end
+      end
+    end
+
+    # Dump this structure's data as a raw bytestring.
+    # @return [String] raw byte sequence
+    def to_bytes
+      return self.pointer.get_bytes(0, self.size)
+    end
+
+    # Serialize data to JSON format
+    def to_json
+      JSON.generate(to_h)
+    end
+
+    # Serialize data for use with the Ruby standard 'Marshal' library.
+    # This function will be invoked when 'Marshal.dump' is called.
+    def marshal_dump
+      to_h
+    end
+
+    # De-serialize data generated by the standard 'Marshal.dump' method.
+    # This function will be invoked when 'Marshal.load' is called.
+    def marshal_load data
+      initialize
+      init_from_hash data
+    end
+
+    # Load data from a variety of different formats.
+    # Currently supports Array, Hash, Bytestring, and JSON.
+    def load(data)
+      case data
+      when Hash
+        init_from_hash data
+      when ::Array
+        init_from_array data
+      when String
+        if data.bytesize == size
+          init_from_bytes data
+        else
+          begin
+            init_from_json data
+          rescue JSON::ParserError
+            # This typically occurs because the string was not JSON at all.
+            # Displaying a JSON-specific exception can be misleading, so use
+            # a generic message instead.
+            raise TypeError, "cannot initialize #{self.class} with the given #{data.class}"
+          end
+        end
+      else
+        raise TypeError, "cannot initialize #{self.class} with type #{data.class}"
+      end
+    end
+
     # Get struct size
     # @return [Numeric]
     def self.size
@@ -226,6 +323,57 @@ def self.auto_ptr
       @managed_type ||= Type::Mapped.new(ManagedStructConverter.new(self))
     end
 
+    protected
+
+    # Initialize the contents of this structure using data from a hash.
+    # @param val [Hash] hash containing field symbols and associated data
+    def init_from_hash(val)
+      clear
+      val.each do |sym, value|
+        raise NoMethodError unless self.members.member?(sym)
+        if self[sym].is_a?(FFI::Struct)
+          self[sym] = self[sym].class.new
+          self[sym].init_from_hash(value)
+        else
+          self[sym] = value
+        end
+      end
+    end
+
+    # Initialize the contents of this structure using elements from an array.
+    # Array data must be in the same order as was used with #layout.
+    # @param ary [Array] array of structure member data
+    def init_from_array(ary)
+      unless ary.length == members.length
+        raise IndexError, "expected #{members.length} items, got #{ary.length}"
+      end
+      clear
+      members.each_with_index do |member, i|
+        if self[member].is_a?(FFI::Struct)
+          self[member] = self[member].class.new
+          self[member].init_from_array(ary[i])
+        else
+          self[member] = ary[i]
+        end
+      end
+    end
+
+    # Initialize the contents of this structure using a bytestring.
+    # @param data [String] byte sequence encoded as a String
+    def init_from_bytes(data)
+      unless data.bytesize == size
+        raise ArgumentError, "string of length #{data.bytesize} cannot initialize a structure with size #{size}"
+      end
+      clear
+      self.pointer.put_bytes(0, data)
+    end
+
+    # De-serialize data from a JSON record
+    def init_from_json(data)
+      h = JSON.parse(data, opts={:symbolize_names => true})
+      init_from_hash h
+    end
+
 
     class << self
       public