Index: trunk/src/data.c
===================================================================
--- trunk/src/data.c	(revision 15140)
+++ trunk/src/data.c	(revision 15141)
@@ -253,42 +253,9 @@
 	list_map0(&data->Element, pcb_element_t, pcb_element_free);
 	list_map0(&data->Rat, pcb_rat_t, pcb_rat_free);
 
-	for (layer = data->Layer, i = 0; i < data->LayerN; layer++, i++) {
-		if (!layer->is_bound)
-			pcb_attribute_free(&layer->meta.real.Attributes);
-		PCB_TEXT_LOOP(layer);
-		{
-			free(text->TextString);
-		}
-		PCB_END_LOOP;
-		PCB_LINE_LOOP(layer);
-		{
-			if (line->Number)
-				free(line->Number);
-		}
-		PCB_END_LOOP;
+	for (layer = data->Layer, i = 0; i < data->LayerN; layer++, i++)
+		pcb_layer_free(layer);
 
-		list_map0(&layer->Line, pcb_line_t, pcb_line_free);
-		list_map0(&layer->Arc,  pcb_arc_t,  pcb_arc_free);
-		list_map0(&layer->Text, pcb_text_t, pcb_text_free);
-		PCB_POLY_LOOP(layer);
-		{
-			pcb_poly_free_fields(polygon);
-		}
-		PCB_END_LOOP;
-		list_map0(&layer->Polygon, pcb_poly_t, pcb_poly_free);
-		if (!layer->is_bound) {
-			if (layer->line_tree)
-				pcb_r_destroy_tree(&layer->line_tree);
-			if (layer->arc_tree)
-				pcb_r_destroy_tree(&layer->arc_tree);
-			if (layer->text_tree)
-				pcb_r_destroy_tree(&layer->text_tree);
-			if (layer->polygon_tree)
-				pcb_r_destroy_tree(&layer->polygon_tree);
-		}
-	}
-
 	if (!subc) {
 		if (data->element_tree)
 			pcb_r_destroy_tree(&data->element_tree);
Index: trunk/src/layer.c
===================================================================
--- trunk/src/layer.c	(revision 15140)
+++ trunk/src/layer.c	(revision 15141)
@@ -39,6 +39,7 @@
 #include "layer_vis.h"
 #include "rtree.h"
 #include "obj_pstk_inlines.h"
+#include "list_common.h"
 
 pcb_virt_layer_t pcb_virt_layers[] = {
 	{"invisible",      PCB_LYT_VIRTUAL + 1, PCB_LYT_VIRTUAL | PCB_LYT_INVIS },
@@ -107,6 +108,44 @@
 	} \
 } while(0)
 
+void pcb_layer_free(pcb_layer_t *layer)
+{
+	if (!layer->is_bound)
+		pcb_attribute_free(&layer->meta.real.Attributes);
+	PCB_TEXT_LOOP(layer);
+	{
+		free(text->TextString);
+	}
+	PCB_END_LOOP;
+	PCB_LINE_LOOP(layer);
+	{
+		if (line->Number)
+			free(line->Number);
+	}
+	PCB_END_LOOP;
+
+	list_map0(&layer->Line, pcb_line_t, pcb_line_free);
+	list_map0(&layer->Arc,  pcb_arc_t,  pcb_arc_free);
+	list_map0(&layer->Text, pcb_text_t, pcb_text_free);
+	PCB_POLY_LOOP(layer);
+	{
+		pcb_poly_free_fields(polygon);
+	}
+	PCB_END_LOOP;
+	list_map0(&layer->Polygon, pcb_poly_t, pcb_poly_free);
+	if (!layer->is_bound) {
+		if (layer->line_tree)
+			pcb_r_destroy_tree(&layer->line_tree);
+		if (layer->arc_tree)
+			pcb_r_destroy_tree(&layer->arc_tree);
+		if (layer->text_tree)
+			pcb_r_destroy_tree(&layer->text_tree);
+		if (layer->polygon_tree)
+			pcb_r_destroy_tree(&layer->polygon_tree);
+	}
+	memset(layer, 0, sizeof(layer));
+}
+
 pcb_bool pcb_layer_is_pure_empty(pcb_layer_t *layer)
 {
 	/* if any local list is non-empty, the layer is non-empty */
Index: trunk/src/layer.h
===================================================================
--- trunk/src/layer.h	(revision 15140)
+++ trunk/src/layer.h	(revision 15141)
@@ -178,6 +178,9 @@
 
 /************ NEW API - new code should use these **************/
 
+/* Free all metadata and objects of a layer; does not free(layer) */
+void pcb_layer_free(pcb_layer_t *layer);
+
 /* Return the layer pointer (or NULL on invalid or virtual layers) for an id */
 pcb_layer_t *pcb_get_layer(pcb_data_t *data, pcb_layer_id_t id);