Correct return values in CPDF_HintTables::CheckPage()

core/src/fpdfapi/fpdf_parser/fpdf_parser_parser.cpp

 // Copyright 2014 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 "parser_int.h"
 
 #include <set>
 #include <utility>
@@ skipping 4889 matching lines @@
   return TRUE;
 }
 int32_t CPDF_HintTables::CheckPage(int index, IFX_DownloadHints* pHints) {
   if (!m_pLinearizedDict || !pHints)
     return IPDF_DataAvail::DataError;
   CPDF_Object* pFirstAvailPage = m_pLinearizedDict->GetElementValue("P");
   int nFirstAvailPage = pFirstAvailPage ? pFirstAvailPage->GetInteger() : 0;
   if (index == nFirstAvailPage)
     return IPDF_DataAvail::DataAvailable;
   FX_DWORD dwLength = GetItemLength(index, m_szPageOffsetArray);
-  if (!dwLength ||
-      !m_pDataAvail->IsDataAvail(m_szPageOffsetArray[index], dwLength,
-                                 pHints)) {
+  // If two pages have the same offset, it should be treated as an error.
+  if (!dwLength)
+    return IPDF_DataAvail::DataError;
+  if (!m_pDataAvail->IsDataAvail(m_szPageOffsetArray[index], dwLength, pHints))
     return IPDF_DataAvail::DataNotAvailable;
-  }
   // Download data of shared objects in the page.
   FX_DWORD offset = 0;
   for (int i = 0; i < index; ++i) {
     offset += m_dwNSharedObjsArray[i];
   }
   CPDF_Object* pFirstPageObj = m_pLinearizedDict->GetElementValue("O");
   int nFirstPageObjNum = pFirstPageObj ? pFirstPageObj->GetInteger() : -1;
   if (nFirstPageObjNum < 0)
-    return FALSE;  // TODO(thestig): Fix this and the return type.
+    return IPDF_DataAvail::DataError;
   FX_DWORD dwIndex = 0;
   FX_DWORD dwObjNum = 0;
   for (int j = 0; j < m_dwNSharedObjsArray[index]; ++j) {
     dwIndex = m_dwIdentifierArray[offset + j];
     if (dwIndex >= m_dwSharedObjNumArray.GetSize())
       return IPDF_DataAvail::DataNotAvailable;
     dwObjNum = m_dwSharedObjNumArray[dwIndex];
     if (dwObjNum >= nFirstPageObjNum &&
         dwObjNum < nFirstPageObjNum + m_nFirstPageSharedObjs) {
       continue;
     }
     dwLength = GetItemLength(dwIndex, m_szSharedObjOffsetArray);
-    if (!dwLength ||
-        !m_pDataAvail->IsDataAvail(m_szSharedObjOffsetArray[dwIndex], dwLength,
+    // If two objects have the same offset, it should be treated as an error.
+    if (!dwLength)
+      return IPDF_DataAvail::DataError;
+    if (!m_pDataAvail->IsDataAvail(m_szSharedObjOffsetArray[dwIndex], dwLength,
                                    pHints)) {
       return IPDF_DataAvail::DataNotAvailable;
     }
   }
   return IPDF_DataAvail::DataAvailable;
 }
 FX_BOOL CPDF_HintTables::LoadHintStream(CPDF_Stream* pHintStream) {
   if (!pHintStream || !m_pLinearizedDict)
     return FALSE;
   CPDF_Dictionary* pDict = pHintStream->GetDict();
@@ skipping 33 matching lines @@
   if (!m_pLinearizedDict)
     return -1;
   CPDF_Array* pRange = m_pLinearizedDict->GetArray("H");
   if (!pRange)
     return -1;
   CPDF_Object* pStreamLen = pRange->GetElementValue(1);
   if (!pStreamLen)
     return -1;
   return pStreamLen->GetInteger();
 }