Fix major memory leak in ADVSceneKeeper

The VM can under no circumstance store it's own data on the heap. Doing
so causes said data to leak into saved VM images. This is the worst kind
of memory leak: even restarting the game will not fix it, because the
data is permanently leaked into the save files.

This will break save compatibility in games that use ADVSceneKeeper
(e.g. Alice 2010 games).

src/hll/AnteaterADVEngine.c

@@ -19,6 +19,7 @@
 #include "system4/utfsjis.h"
 
 #include "vm/page.h"
+#include "xsystem4.h"
 
 #include "AnteaterADVEngine.h"
 #include "iarray.h"
@@ -309,7 +310,14 @@ bool ADVSceneKeeper_AddADVScene(struct page **page)
 		return false;
 	}
 	scenes.data = xrealloc_array(scenes.data, scenes.n, scenes.n+1, sizeof(struct page*));
-	scenes.data[scenes.n++] = copy_page(*page);
+
+	// serialize
+	struct iarray_writer out;
+	iarray_init_writer(&out, "SCN");
+	iarray_write_struct(&out, *page);
+	scenes.data[scenes.n++] = iarray_to_page(&out);
+	iarray_free_writer(&out);
+
 	return true;
 }
 
@@ -323,19 +331,23 @@ bool ADVSceneKeeper_GetADVScene(int index, struct page **page)
 	if (index < 0 || (unsigned)index >= scenes.n)
 		return false;
 
+	// deserialize
+	struct iarray_reader in;
+	if (!iarray_init_reader(&in, scenes.data[index], "SCN"))
+		return false;
+
 	if (*page) {
 		delete_page_vars(*page);
 		free_page(*page);
 	}
 
-	*page = copy_page(scenes.data[index]);
-	return true;
+	*page = iarray_read_struct(&in, scene_struct_no());
+	return !in.error;
 }
 
 void ADVSceneKeeper_Clear(void)
 {
 	for (unsigned i = 0; i < scenes.n; i++) {
-		delete_page_vars(scenes.data[i]);
 		free_page(scenes.data[i]);
 	}
 	free(scenes.data);
@@ -353,11 +365,11 @@ bool ADVSceneKeeper_Save(struct page **iarray)
 	//       this implementation just serializes whatever it's given. Note
 	//       also that the structure of 画面保管_t objects differs between games.
 	struct iarray_writer w;
-	iarray_init_writer(&w, "ADS");
-	iarray_write(&w, 3); // version? Mankuchu puts 3 here
+	iarray_init_writer(&w, "SCS");
+	iarray_write(&w, 0); // version
 	iarray_write(&w, scenes.n);
 	for (unsigned i = 0; i < scenes.n; i++) {
-		iarray_write_struct(&w, scenes.data[i]);
+		iarray_write_array(&w, scenes.data[i]);
 	}
 	*iarray = iarray_to_page(&w);
 	iarray_free_writer(&w);
@@ -372,10 +384,12 @@ bool ADVSceneKeeper_Load(struct page **iarray)
 	ADVSceneKeeper_Clear();
 
 	struct iarray_reader r;
-	iarray_init_reader(&r, *iarray, "ADS");
+	iarray_init_reader(&r, *iarray, "SCS");
 
-	if (iarray_read(&r) != 3)
+	if (iarray_read(&r) != 0) {
+		WARNING("Unsupported version of ADVSceneKeeper 'SCS' data");
 		goto error;
+	}
 
 	int nr_scenes = iarray_read(&r);
 	if (nr_scenes < 0 || nr_scenes > 10000)
@@ -384,9 +398,9 @@ bool ADVSceneKeeper_Load(struct page **iarray)
 	scenes.n = 0;
 	scenes.data = xcalloc(nr_scenes, sizeof(struct page*));
 
-	int struct_type = scene_struct_no();
 	for (int i = 0; i < nr_scenes; i++) {
-		scenes.data[scenes.n++] = iarray_read_struct(&r, struct_type);
+		struct ain_type type = { .data = AIN_ARRAY_INT, .struc = 0, .rank = 0 };
+		scenes.data[scenes.n++] = iarray_read_array(&r, &type);
 		if (r.error)
 			goto error;
 	}