From 10b96b08b8dee4fb9d107fb8f367796121a35f31 Mon Sep 17 00:00:00 2001
From: Glenn Maynard <gmaynard@users.sourceforge.net>
Date: Sun, 15 Oct 2006 01:40:11 +0000
Subject: [PATCH] LuaHelpers::DeepCopy

---
 stepmania/src/LuaManager.cpp | 15 +++++++++++++++
 stepmania/src/LuaManager.h   |  4 ++++
 2 files changed, 19 insertions(+)

diff --git a/stepmania/src/LuaManager.cpp b/stepmania/src/LuaManager.cpp
index 8824c7e94d..99af8fe295 100644
--- a/stepmania/src/LuaManager.cpp
+++ b/stepmania/src/LuaManager.cpp
@@ -659,6 +659,21 @@ int LuaHelpers::TypeError( Lua *L, int iArgNo, const char *szName )
 	}
 }
 
+void LuaHelpers::DeepCopy( lua_State *L )
+{
+	luaL_checktype( L, -2, LUA_TTABLE );
+	luaL_checktype( L, -1, LUA_TTABLE );
+
+	/* Call DeepCopy(t, u), where t is our referenced object and u is the new table. */
+	lua_getglobal( L, "DeepCopy" );
+
+	ASSERT_M( !lua_isnil(L, -1), "DeepCopy() missing" );
+	ASSERT_M( lua_isfunction(L, -1), "DeepCopy() not a function" );
+	lua_insert( L, lua_gettop(L)-2 );
+
+	lua_call( L, 2, 0 );
+}
+
 namespace
 {
 	int lua_pushvalues( lua_State *L )
diff --git a/stepmania/src/LuaManager.h b/stepmania/src/LuaManager.h
index e6b709db17..c643be3412 100644
--- a/stepmania/src/LuaManager.h
+++ b/stepmania/src/LuaManager.h
@@ -62,6 +62,10 @@ namespace LuaHelpers
 	/* Create a Lua array (a table with indices starting at 1) of the given vector,
 	 * and push it on the stack. */
 	void CreateTableFromArrayB( Lua *L, const vector<bool> &aIn );
+	
+	/* Recursively copy elements from the table at stack element -2 into the table
+	 * at stack -1.  Pop both elements from the stack. */
+	void DeepCopy( lua_State *L );
 
 	/* Read the table at the top of the stack back into a vector. */
 	void ReadArrayFromTableB( Lua *L, vector<bool> &aOut );