From 4601331deee2a3f23e07cd527f023dfe5202a8ca Mon Sep 17 00:00:00 2001
From: samuele3hu <qingkui.hu@cocos2d-x.org>
Date: Fri, 16 Jan 2015 09:50:22 +0800
Subject: [PATCH] Update the luaval_to_int32 conversional function to get
 correct value

---
 .../lua-bindings/manual/LuaBasicConversions.cpp | 17 ++++++++++++++++-
 1 file changed, 16 insertions(+), 1 deletion(-)

diff --git a/cocos/scripting/lua-bindings/manual/LuaBasicConversions.cpp b/cocos/scripting/lua-bindings/manual/LuaBasicConversions.cpp
index aff5722a60..16d87fb625 100644
--- a/cocos/scripting/lua-bindings/manual/LuaBasicConversions.cpp
+++ b/cocos/scripting/lua-bindings/manual/LuaBasicConversions.cpp
@@ -121,7 +121,22 @@ bool luaval_to_int32(lua_State* L,int lo,int* outValue, const char* funcName)
     
     if (ok)
     {
-        *outValue = (int)(unsigned int)lua_tonumber(L, lo);
+        /**
+         When we want to convert the number value from the Lua to int, we would call lua_tonumber to implement.It would
+         experience two phase conversion: int -> double, double->int.But,for the 0x80000000 which the min value of int, the
+         int cast may return an undefined result,like 0x7fffffff.So we must use the (int)(unsigned int)lua_tonumber() to get
+         predictable results for 0x80000000.In this place,we didn't use lua_tointeger, because it may produce differen results
+         depending on the compiler,e.g:for iPhone4s,it also get wrong value for 0x80000000.
+         */
+        unsigned int estimateValue = (unsigned int)lua_tonumber(L, lo);
+        if (estimateValue == std::numeric_limits<int>::min())
+        {
+            *outValue = (int)estimateValue;
+        }
+        else
+        {
+            *outValue = (int)lua_tonumber(L, lo);
+        }
     }
     
     return ok;