Relax a check in CPDF_HintTables.

core/fpdfapi/fpdf_parser/cpdf_hint_tables.cpp

 // Copyright 2016 PDFium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 // Original code copyright 2014 Foxit Software Inc. http://www.foxitsoftware.com
 
 #include "core/fpdfapi/fpdf_parser/cpdf_hint_tables.h"
 
 #include "core/fpdfapi/fpdf_parser/include/cpdf_data_avail.h"
 #include "core/fpdfapi/fpdf_parser/include/cpdf_array.h"
@@ skipping 278 matching lines @@
       if (i == 0)
         m_szSharedObjOffsetArray.push_back(m_szFirstPageObjOffset);
     } else {
       FX_SAFE_UINT32 safeObjNum = dwFirstSharedObjNum;
       safeObjNum += i - m_nFirstPageSharedObjs;
       if (!safeObjNum.IsValid())
         return FALSE;
 
       m_dwSharedObjNumArray.Add(safeObjNum.ValueOrDie());
       if (i == m_nFirstPageSharedObjs) {
-        m_szSharedObjOffsetArray.push_back(
-            pdfium::base::checked_cast<int32_t>(dwFirstSharedObjLoc));
+        FX_SAFE_FILESIZE safeLoc = dwFirstSharedObjLoc;
+        if (!safeLoc.IsValid())
+          return FALSE;
+
+        m_szSharedObjOffsetArray.push_back(safeLoc.ValueOrDie());
       }
     }
 
     if (i != 0 && i != m_nFirstPageSharedObjs) {
-      FX_SAFE_INT32 safeLoc = pdfium::base::checked_cast<int32_t>(dwPrevObjLen);
+      FX_SAFE_FILESIZE safeLoc = dwPrevObjLen;
       safeLoc += m_szSharedObjOffsetArray[i - 1];
       if (!safeLoc.IsValid())
         return FALSE;
 
       m_szSharedObjOffsetArray.push_back(safeLoc.ValueOrDie());
     }
   }
 
   if (dwSharedObjTotal > 0) {
-    FX_SAFE_INT32 safeLoc = pdfium::base::checked_cast<int32_t>(dwCurObjLen);
+    FX_SAFE_FILESIZE safeLoc = dwCurObjLen;
     safeLoc += m_szSharedObjOffsetArray[dwSharedObjTotal - 1];
     if (!safeLoc.IsValid())
       return FALSE;
 
     m_szSharedObjOffsetArray.push_back(safeLoc.ValueOrDie());
   }
 
   hStream->ByteAlign();
   if (hStream->BitsRemaining() < dwSharedObjTotal)
     return FALSE;
@@ skipping 150 matching lines @@
   CPDF_Array* pRange = m_pLinearizedDict->GetArrayBy("H");
   if (!pRange)
     return -1;
 
   CPDF_Object* pStreamLen = pRange->GetDirectObjectAt(1);
   if (!pStreamLen)
     return -1;
 
   return pStreamLen->GetInteger();
 }