added DL::Importer.sizeof().

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@7897 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

ext/dl/cptr.c

@@ -10,6 +10,8 @@
 
 VALUE rb_cDLCPtr;
 
+static ID id_to_ptr;
+
 static void
 dlptr_free(struct ptr_data *data)
 {
@@ -422,6 +424,15 @@ rb_dlptr_s_to_ptr(VALUE self, VALUE val)
 #endif
 	return rb_dlptr_new(fp, sizeof(FILE), NULL);
     }
+    else if( rb_respond_to(val, id_to_ptr) ){
+	VALUE vptr = rb_funcall(val, id_to_ptr, 0);
+	if( rb_obj_is_kind_of(vptr, rb_cDLCPtr) ){
+	    return vptr;
+	}
+	else{
+	    rb_raise(rb_eDLError, "to_ptr should return a CPtr object.");
+	}
+    }
     else{
 	return rb_dlptr_new(NUM2PTR(rb_Integer(val)), 0, NULL);
     }
@@ -430,6 +441,8 @@ rb_dlptr_s_to_ptr(VALUE self, VALUE val)
 void
 Init_dlptr()
 {
+    id_to_ptr = rb_intern("to_ptr");
+
     rb_cDLCPtr = rb_define_class_under(rb_mDL, "CPtr", rb_cObject);
     rb_define_alloc_func(rb_cDLCPtr, rb_dlptr_s_allocate);
     rb_define_singleton_method(rb_cDLCPtr, "malloc", rb_dlptr_s_malloc, -1);

ext/dl/lib/dl/import.rb

@@ -62,6 +62,38 @@ module DL
       @type_alias[alias_type] = orig_type
     end
 
+    def sizeof(ty)
+      case ty
+      when String
+        ty = parse_ctype(ty, @type_alias).abs()
+        case ty
+        when TYPE_CHAR
+          return SIZEOF_CHAR
+        when TYPE_SHORT
+          return SIZEOF_SHORT
+        when TYPE_INT
+          return SIZEOF_INT
+        when TYPE_LONG
+          return SIZEOF_LONG
+        when TYPE_LONG_LONG
+          return SIZEOF_LONG_LON
+        when TYPE_FLOAT
+          return SIZEOF_FLOAT
+        when TYPE_DOUBLE
+          return SIZEOF_DOUBLE
+        when TYPE_VOIDP
+          return SIZEOF_VOIDP
+        else
+          raise(DLError, "unknown type: #{ty}")
+        end
+      when Class
+        if( ty.instance_methods().include?("to_ptr") )
+          return ty.size()
+        end
+      end
+      return CPtr[ty].size()
+    end
+
     def parse_bind_options(opts)
       h = {}
       prekey = nil

ext/dl/test/test_import.rb

@@ -40,6 +40,11 @@ module DL
   end
 
   class TestImport < TestBase
+    def test_sizeof()
+      assert_equal(DL::SIZEOF_VOIDP, LIBC.sizeof("FILE*"))
+      assert_equal(LIBC::MyStruct.size(), LIBC.sizeof(LIBC::MyStruct))
+    end
+
     def test_unsigned_result()
       d = (2 ** 31) + 1