MdePkg/BaseUefiDecompressLib: Improve performance of boundary validation

The boundary validation checking in MakeTable() performs on
every loop iteration. This could be improved by checking
just once before the loop.
https://bugzilla.tianocore.org/show_bug.cgi?id=1329

Cc: Michael D Kinney <michael.d.kinney@intel.com>
Cc: Liming Gao <liming.gao@intel.com>
Contributed-under: TianoCore Contribution Agreement 1.1
Signed-off-by: Shenglei Zhang <shenglei.zhang@intel.com>
Reviewed-by: Liming Gao <liming.gao@intel.com>

1 files changed, 4 insertions, 3 deletions

diff --git a/MdePkg/Library/BaseUefiDecompressLib/BaseUefiDecompressLib.c b/MdePkg/Library/BaseUefiDecompressLib/BaseUefiDecompressLib.c
index c1e8c5581a..3d5b7a737a 100644
--- a/MdePkg/Library/BaseUefiDecompressLib/BaseUefiDecompressLib.c
+++ b/MdePkg/Library/BaseUefiDecompressLib/BaseUefiDecompressLib.c
@@ -222,10 +222,11 @@ MakeTable (
 

     if (Len <= TableBits) {

 

+      if (Start[Len] >= NextCode || NextCode > MaxTableLength){

+        return (UINT16) BAD_TABLE;

+      }

+

       for (Index = Start[Len]; Index < NextCode; Index++) {

-        if (Index >= MaxTableLength) {

-          return (UINT16) BAD_TABLE;

-        }

         Table[Index] = Char;

       }