inline structures data type for mruby (MRB_TT_INLINE) (fix #3237)

Inline structures have no instance variables, no finalizer, and offer as much space as possible in RBASIC object. This means 24 bytes on 64-bit platforms and 12 bytes on 32-bit platforms.
mruby-inline-struct gem is only provided for testing.

1 files changed, 83 insertions, 0 deletions

diff --git a/mrbgems/mruby-inline-struct/test/inline.c b/mrbgems/mruby-inline-struct/test/inline.c
new file mode 100644
index 000000000..903c08aca
--- /dev/null
+++ b/mrbgems/mruby-inline-struct/test/inline.c
@@ -0,0 +1,83 @@
+#include <mruby.h>
+#include <mruby/class.h>
+#include <mruby/string.h>
+#include <mruby/inline.h>
+
+static mrb_value
+inline_test_initialize(mrb_state *mrb, mrb_value self)
+{
+  char *string = mrb_inline_ptr(self);
+  mrb_int size = mrb_inline_size();
+  mrb_value object;
+  mrb_get_args(mrb, "o", &object);
+
+  if (mrb_float_p(object))
+  {
+    snprintf(string, size, "float(%.3f)", mrb_float(object));
+  }
+  else if (mrb_fixnum_p(object))
+  {
+    snprintf(string, size, "fixnum(%d)", mrb_fixnum(object));
+  }
+  else if (mrb_string_p(object))
+  {
+    snprintf(string, size, "string(%s)", mrb_string_value_cstr(mrb, &object));
+  }
+
+  string[size - 1] = 0; // force NULL at the end
+  return self;
+}
+
+static mrb_value
+inline_test_to_s(mrb_state *mrb, mrb_value self)
+{
+  return mrb_str_new_cstr(mrb, mrb_inline_ptr(self));
+}
+
+static mrb_value
+inline_test_length(mrb_state *mrb, mrb_value self)
+{
+  return mrb_fixnum_value(mrb_inline_size());
+}
+
+static mrb_value
+inline_test_test_receive(mrb_state *mrb, mrb_value self)
+{
+  mrb_value object;
+  mrb_get_args(mrb, "o", &object);
+  if (mrb_obj_class(mrb, object) != mrb_class_get(mrb, "InlineStructTest"))
+  {
+    mrb_raisef(mrb, E_TYPE_ERROR, "Expected InlineStructTest");
+  }
+  return mrb_bool_value(((char*)mrb_inline_ptr(object))[0] == 's');
+}
+
+static mrb_value
+inline_test_test_receive_direct(mrb_state *mrb, mrb_value self)
+{
+  char *ptr;
+  mrb_get_args(mrb, "I", &ptr);
+  return mrb_bool_value(ptr[0] == 's');
+}
+
+static mrb_value
+inline_test_mutate(mrb_state *mrb, mrb_value self)
+{
+  char *ptr = mrb_inline_ptr(self);
+  memcpy(ptr, "mutate", 6);
+  return mrb_nil_value();
+}
+
+void mrb_mruby_inline_struct_gem_test(mrb_state *mrb)
+{
+  struct RClass *cls;
+
+  cls = mrb_define_class(mrb, "InlineStructTest", mrb->object_class);
+  MRB_SET_INSTANCE_TT(cls, MRB_TT_INLINE);
+  mrb_define_method(mrb, cls, "initialize", inline_test_initialize, MRB_ARGS_REQ(1));
+  mrb_define_method(mrb, cls, "to_s", inline_test_to_s, MRB_ARGS_NONE());
+  mrb_define_method(mrb, cls, "mutate", inline_test_mutate, MRB_ARGS_NONE());
+  mrb_define_class_method(mrb, cls, "length", inline_test_length, MRB_ARGS_NONE());
+  mrb_define_class_method(mrb, cls, "test_receive", inline_test_test_receive, MRB_ARGS_REQ(1));
+  mrb_define_class_method(mrb, cls, "test_receive_direct", inline_test_test_receive_direct, MRB_ARGS_REQ(1));
+}