AGS: Make NumberPtr a class instead of a union

It's illegal to reference an inactive member of a union and the types
are not layout compatible (and even not of the same size).
Instead, store every value in a integer of pointer size and cast
pointers to and from it.
This should really fix bug #13557.

engines/ags/engine/gui/my_listbox.cpp

@@ -132,7 +132,7 @@ void MyListBox::additem(char *texx) {
 
 int MyListBox::processmessage(int mcode, int wParam, NumberPtr lParam) {
 	if (mcode == CLB_ADDITEM) {
-		additem((char *)lParam._ptr);
+		additem((char *)lParam.ptr());
 	} else if (mcode == CLB_CLEAR)
 		clearlist();
 	else if (mcode == CLB_GETCURSEL)
@@ -146,12 +146,12 @@ int MyListBox::processmessage(int mcode, int wParam, NumberPtr lParam) {
 		if (topitem + numonscreen <= selected)
 			topitem = (selected + 1) - numonscreen;
 	} else if (mcode == CLB_GETTEXT)
-		Common::strcpy_s((char *)lParam._ptr, 260, itemnames[wParam]);
+		Common::strcpy_s((char *)lParam.ptr(), 260, itemnames[wParam]);
 	else if (mcode == CLB_SETTEXT) {
 		if (wParam < items)
 			free(itemnames[wParam]);
 
-		char *newstri = (char *)lParam._ptr;
+		char *newstri = (char *)lParam.ptr();
 		size_t ln = strlen(newstri) + 2;
 		itemnames[wParam] = (char *)malloc(ln);
 		Common::strcpy_s(itemnames[wParam], ln, newstri);

engines/ags/engine/gui/my_textbox.cpp

@@ -64,10 +64,10 @@ int MyTextBox::pressedon(int /*mx*/, int /*my*/) {
 int MyTextBox::processmessage(int mcode, int wParam, NumberPtr lParam) {
 
 	if (mcode == CTB_SETTEXT) {
-		snprintf(text, sizeof(text), "%s", (const char *)lParam._ptr);
+		snprintf(text, sizeof(text), "%s", (const char *)lParam.ptr());
 		needredraw = 1;
 	} else if (mcode == CTB_GETTEXT)
-		Common::strcpy_s((char *)lParam._ptr, 260, text); // FIXME! dangerous
+		Common::strcpy_s((char *)lParam.ptr(), 260, text); // FIXME! dangerous
 	else if (mcode == CTB_KEYPRESS) {
 		// NOTE: this deprecated control does not support UTF-8
 		int key = wParam;

engines/ags/engine/script/cc_instance.cpp

@@ -1221,8 +1221,8 @@ int ccInstance::Run(int32_t curpc) {
 					// call only supports a 32-bit value. This is fine in most cases, since
 					// methods mostly set the ptr on GlobalReturnValue, so it doesn't reach here.
 					// But just in case, throw a wobbly if it reaches here with a 64-bit pointer
-					if (fnResult._ptr > reinterpret_cast<void *>(static_cast<uintptr>(0xffffffffu)))
-						error("Uhandled 64-bit pointer result from plugin method call");
+					if (fnResult.full() > static_cast<intptr_t>(0xffffffffu))
+						error("Unhandled 64-bit pointer result from plugin method call");
 
 					return_value.SetPluginArgument(fnResult);
 				}

engines/ags/shared/core/types.h

@@ -105,28 +105,29 @@ enum {
 };
 
 /**
- * Basic union that can be either a number or a pointer. Helps avoid some
+ * Basic class that can hold either a number or a pointer. Helps avoid some
  * of the more nasty casts the codebase does, which was causing issues
  * on 64-bit systems
  */
-union NumberPtr {
-	int32 _value;
-	void *_ptr;
-	const void *_constPtr;
+class NumberPtr {
+	intptr_t _value;
 
-	NumberPtr() : _ptr(nullptr) {
+public:
+	NumberPtr() : _value(0) {
 	}
-	NumberPtr(int value) {
-		_ptr = nullptr;
+	NumberPtr(int32_t value) {
 		_value = value;
 	}
-	NumberPtr(void *ptr) : _ptr(ptr) {
+	NumberPtr(void *ptr) : _value((intptr_t)ptr) {
 	}
-	NumberPtr(const void *ptr) : _constPtr(ptr) {
+	NumberPtr(const void *ptr) : _value((intptr_t)ptr) {
 	}
-	operator int() const {
-		return _value;
+	operator int32_t() const {
+		return (int32_t)_value;
 	}
+	intptr_t full() const { return _value; }
+	void *ptr() const { return (void *)_value; }
+	const void *cptr() const { return (const void *)_value; }
 };
 
 } // namespace AGS3