# HG changeset patch
# User Paul Boddie <paul@boddie.org.uk>
# Date 1716233214 -7200
# Node ID fb368817a23bbae69b093ef81df99f4ae993ddad
# Parent  c8b0c2d6df5c831b24eea9b94bf3c8028cad4b77
Introduced an object size member to object structures, being set to a non-zero
value in copiable type class structures to indicate that value replacement can
occur with instances of such classes, with the given size being used to copy
these instances.

diff -r c8b0c2d6df5c -r fb368817a23b generator.py
--- a/generator.py	Mon May 20 01:06:05 2024 +0200
+++ b/generator.py	Mon May 20 21:26:54 2024 +0200
@@ -3,7 +3,7 @@
 """
 Generate C code from object layouts and other deduced information.
 
-Copyright (C) 2015-2019, 2021, 2023 Paul Boddie <paul@boddie.org.uk>
+Copyright (C) 2015-2019, 2021, 2023, 2024 Paul Boddie <paul@boddie.org.uk>
 
 This program is free software; you can redistribute it and/or modify it under
 the terms of the GNU General Public License as published by the Free Software
@@ -70,6 +70,13 @@
         dict_type, list_type, tuple_type
         )
 
+    # Copiable types.
+
+    copiable_types = [
+        "__builtins__.core.wrapper",
+        float_type,
+        ]
+
     # Data types with a trailing data member of the given native types.
 
     trailing_data_types = {
@@ -859,6 +866,7 @@
 typedef struct {
     const __table * table;
     __pos pos;
+    __int obj_size;
     __attr attrs[%s];
 %s
 } %s;
@@ -880,6 +888,10 @@
         obj_type = ref.has_kind("<instance>") and encode_symbol("obj", origin) or "__obj"
         obj_name = encode_path(structure_name)
 
+        obj_size = ref.has_kind("<class>") and structure_name in self.copiable_types and \
+            "sizeof(%s)" % encode_symbol("obj", structure_name) or \
+            "0"
+
         if f_decls:
             print >>f_decls, "extern %s %s;\n" % (obj_type, obj_name)
 
@@ -887,6 +899,7 @@
 %s %s = {
     &%s,
     %s,
+    %s,
     {
         %s
     },
@@ -896,6 +909,7 @@
             obj_type, obj_name,
             table_name,
             pos,
+            obj_size,
             ",\n        ".join(structure),
             trailing and ",\n    ".join(trailing) or "")
 
diff -r c8b0c2d6df5c -r fb368817a23b templates/ops.c
--- a/templates/ops.c	Mon May 20 01:06:05 2024 +0200
+++ b/templates/ops.c	Mon May 20 21:26:54 2024 +0200
@@ -1,6 +1,6 @@
 /* Common operations.
 
-Copyright (C) 2015, 2016, 2017, 2018, 2023 Paul Boddie <paul@boddie.org.uk>
+Copyright (C) 2015-2018, 2023, 2024 Paul Boddie <paul@boddie.org.uk>
 
 This program is free software; you can redistribute it and/or modify it under
 the terms of the GNU General Public License as published by the Free Software
@@ -441,14 +441,12 @@
 }
 
 /* Store an attribute in a target location. For targets that support value
-   replacement, a copied object is assigned when initialising the target.
-
-   NOTE: Only floats and wrappers are currently supported for value replacement.
-         A special copy attribute could be employed to make this generic. */
+   replacement, a copied object is assigned when initialising the target. */
 
 __attr __set_attr(volatile __attr *target, __attr attr)
 {
     __ref obj;
+    int obj_size;
 
     /* Value already replaced in target by an operation. */
 
@@ -462,10 +460,10 @@
 
     if ((obj != NULL) && __is_instance(obj))
     {
-        if (__get_class(obj) == &__builtins___float_float)
-            attr = __ATTRVALUE(__COPY(obj, __INSTANCESIZE(__builtins___float_float)));
-        else if (__get_class(obj) == &__builtins___core_wrapper)
-            attr = __ATTRVALUE(__COPY(obj, __INSTANCESIZE(__builtins___core_wrapper)));
+        obj_size = __get_class(obj)->obj_size;
+
+        if (obj_size)
+            attr = __ATTRVALUE(__COPY(obj, obj_size));
     }
 
     /* Set and return the attribute. */
diff -r c8b0c2d6df5c -r fb368817a23b templates/types.h
--- a/templates/types.h	Mon May 20 01:06:05 2024 +0200
+++ b/templates/types.h	Mon May 20 21:26:54 2024 +0200
@@ -1,6 +1,6 @@
 /* Runtime types.
 
-Copyright (C) 2015-2019, 2021, 2023 Paul Boddie <paul@boddie.org.uk>
+Copyright (C) 2015-2019, 2021, 2023, 2024 Paul Boddie <paul@boddie.org.uk>
 
 This program is free software; you can redistribute it and/or modify it under
 the terms of the GNU General Public License as published by the Free Software
@@ -107,6 +107,8 @@
 {
     const __table * table;      /* attribute table */
     __ppos pos;                 /* position of attribute indicating class */
+    __int obj_size;             /* object size for copiable objects defined
+                                   on class */
     __attr attrs[];             /* attributes */
 
     /* Specialisations of this type may add other members.