From 2cf954b8ae08a9094354551ee3733f4ff8078443 Mon Sep 17 00:00:00 2001
From: Roberto Ierusalimschy <roberto@inf.puc-rio.br>
Date: Tue, 8 Nov 1994 17:56:39 -0200
Subject: [PATCH] lock mechanism

---
 fallback.c | 67 +++++++++++++++++++++++++++++++++++++++++++++++++++++-
 fallback.h |  6 ++++-
 lua.h      |  6 ++++-
 opcode.c   | 14 ++++++++++--
 4 files changed, 88 insertions(+), 5 deletions(-)

diff --git a/fallback.c b/fallback.c
index 023d11c3..68d052b3 100644
--- a/fallback.c
+++ b/fallback.c
@@ -3,11 +3,13 @@
 ** TecCGraf - PUC-Rio
 */
  
-char *rcs_fallback="$Id: $";
+char *rcs_fallback="$Id: fallback.c,v 1.1 1994/11/07 15:20:56 roberto Exp roberto $";
 
 #include <stdio.h>
+#include <stdlib.h>
  
 #include "fallback.h"
+#include "opcode.h"
 #include "lua.h"
 
 
@@ -49,3 +51,66 @@ void luaI_orderFB (void)
   lua_error("unexpected type at comparison");
 }
 
+
+/*
+** Lock routines
+*/
+
+static Object *lockArray = NULL;
+static int lockSize = 0;
+
+int lua_lock (lua_Object object)
+{
+  int i;
+  int oldSize;
+  if (lua_isnil(object))
+    return -1;
+  for (i=0; i<lockSize; i++)
+    if (tag(&lockArray[i]) == LUA_T_NIL)
+    {
+      lockArray[i] = *luaI_Address(object);
+      return i;
+    }
+  /* no more empty spaces */
+  oldSize = lockSize;
+  if (lockArray == NULL)
+  {
+    lockSize = 10;
+    lockArray = (Object *)malloc(lockSize);
+  }
+  else
+  {
+    lockSize = 3*oldSize/2 + 5;
+    lockArray = (Object *)realloc(lockArray, lockSize);
+  }
+  if (lockArray == NULL)
+  {
+    lockSize = 0;
+    lua_error("lock - not enough memory");
+  }
+  for (i=oldSize; i<lockSize; i++)
+    tag(&lockArray[i]) = LUA_T_NIL;
+  lockArray[oldSize] = *luaI_Address(object);
+  return oldSize;
+}
+
+
+void lua_unlock (int ref)
+{
+  tag(&lockArray[ref]) = LUA_T_NIL;
+}
+
+
+Object *luaI_getlocked (int ref)
+{
+  return &lockArray[ref];
+}
+
+
+void luaI_travlock (void (*fn)(Object *))
+{
+  int i;
+  for (i=0; i<lockSize; i++)
+    fn(&lockArray[i]);
+}
+
diff --git a/fallback.h b/fallback.h
index 71080abd..b9b695fd 100644
--- a/fallback.h
+++ b/fallback.h
@@ -1,16 +1,20 @@
 /*
-** $Id: $
+** $Id: fallback.h,v 1.1 1994/11/07 15:20:56 roberto Exp roberto $
 */
  
 #ifndef fallback_h
 #define fallback_h
 
+#include "opcode.h"
+
 void luaI_errorFB (void);
 void luaI_indexFB (void);
 void luaI_gettableFB (void);
 void luaI_arithFB (void);
 void luaI_concatFB (void);
 void luaI_orderFB (void);
+Object *luaI_getlocked (int ref);
+void luaI_travlock (void (*fn)(Object *));
 
 #endif
 
diff --git a/lua.h b/lua.h
index 11be9a6a..2a9e30b3 100644
--- a/lua.h
+++ b/lua.h
@@ -2,7 +2,7 @@
 ** LUA - Linguagem para Usuarios de Aplicacao
 ** Grupo de Tecnologia em Computacao Grafica
 ** TeCGraf - PUC-Rio
-** $Id: lua.h,v 3.3 1994/11/07 16:34:44 roberto Exp $
+** $Id: lua.h,v 3.4 1994/11/07 18:27:39 roberto Exp roberto $
 */
 
 
@@ -60,6 +60,10 @@ lua_Object     lua_getsubscript         (void);
 
 int            lua_type 		(lua_Object object);
 
+int	       lua_lock			(lua_Object object);
+lua_Object     lua_getlocked		(int ref);
+void	       lua_unlock		(int ref);
+
 
 /* for lua 1.1 */
 
diff --git a/opcode.c b/opcode.c
index 0c30069b..1f6573cd 100644
--- a/opcode.c
+++ b/opcode.c
@@ -3,7 +3,7 @@
 ** TecCGraf - PUC-Rio
 */
 
-char *rcs_opcode="$Id: opcode.c,v 3.4 1994/11/07 16:34:44 roberto Exp roberto $";
+char *rcs_opcode="$Id: opcode.c,v 3.5 1994/11/07 18:27:39 roberto Exp $";
 
 #include <stdio.h>
 #include <stdlib.h>
@@ -545,14 +545,24 @@ void *lua_getuserdata (lua_Object object)
  else return (uvalue(Address(object)));
 }
 
+
+lua_Object lua_getlocked (int ref)
+{
+ adjustC(0);
+ *(top++) = *luaI_getlocked(ref);
+ CBase++;  /* incorporate object in the stack */
+ return Ref(top-1);
+}
+
 /*
 ** Get a global object. Return the object handle or NULL on error.
 */
 lua_Object lua_getglobal (char *name)
 {
  int n = lua_findsymbol(name);
- if (n < 0) return 0;
+ adjustC(0);
  *(top++) = s_object(n);
+ CBase++;  /* incorporate object in the stack */
  return Ref(top-1);
 }