[PATCH v2 1/3] BaseTools/TianoCompress: Improve performance of boundary validation

[shenglei <shenglei.zhang@intel.com>]

From: Shenglei Zhang <shenglei.zhang@intel.com>

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: Bob Feng <bob.c.feng@intel.com>
Cc: Liming Gao <liming.gao@intel.com>
Cc: Yonghong Zhu <yonghong.zhu@intel.com>
Contributed-under: TianoCore Contribution Agreement 1.1
Signed-off-by: Shenglei Zhang <shenglei.zhang@intel.com>
---
 BaseTools/Source/C/TianoCompress/TianoCompress.c | 7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/BaseTools/Source/C/TianoCompress/TianoCompress.c b/BaseTools/Source/C/TianoCompress/TianoCompress.c
index 29b11c597f..ae88074360 100644
--- a/BaseTools/Source/C/TianoCompress/TianoCompress.c
+++ b/BaseTools/Source/C/TianoCompress/TianoCompress.c
@@ -2281,10 +2281,11 @@ Returns:
 
     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;
       }
 
-- 
2.18.0.windows.1