Use std::map as CPDF_Dictionary's underlying store.

fpdfsdk/src/fpdfview.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 "public/fpdfview.h"
 
 #include <memory>
 
@@ skipping 809 matching lines @@
 DLLEXPORT FPDF_DWORD STDCALL FPDF_CountNamedDests(FPDF_DOCUMENT document) {
   CPDF_Document* pDoc = CPDFDocumentFromFPDFDocument(document);
   if (!pDoc)
     return 0;
 
   CPDF_Dictionary* pRoot = pDoc->GetRoot();
   if (!pRoot)
     return 0;
 
   CPDF_NameTree nameTree(pDoc, "Dests");
-  int count = nameTree.GetCount();
+  pdfium::base::CheckedNumeric<FPDF_DWORD> count = nameTree.GetCount();
   CPDF_Dictionary* pDest = pRoot->GetDict("Dests");
   if (pDest)
     count += pDest->GetCount();
-  return count;
+
+  if (!count.IsValid())
+    return 0;
+
+  return count.ValueOrDie();
 }
 
 DLLEXPORT FPDF_DEST STDCALL FPDF_GetNamedDestByName(FPDF_DOCUMENT document,
                                                     FPDF_BYTESTRING name) {
   if (!name || name[0] == 0)
     return nullptr;
 
   CPDF_Document* pDoc = CPDFDocumentFromFPDFDocument(document);
   if (!pDoc)
     return nullptr;
@@ skipping 13 matching lines @@
     return nullptr;
 
   CPDF_Document* pDoc = CPDFDocumentFromFPDFDocument(document);
   if (!pDoc)
     return nullptr;
 
   CPDF_Dictionary* pRoot = pDoc->GetRoot();
   if (!pRoot)
     return nullptr;
 
-  CPDF_Object* pDestObj = NULL;
+  CPDF_Object* pDestObj = nullptr;
   CFX_ByteString bsName;
   CPDF_NameTree nameTree(pDoc, "Dests");
   int count = nameTree.GetCount();
   if (index >= count) {
     CPDF_Dictionary* pDest = pRoot->GetDict("Dests");
     if (!pDest)
-      return NULL;
-    if (index >= count + pDest->GetCount())
-      return NULL;
+      return nullptr;
+
+    pdfium::base::CheckedNumeric<int> checked_count = count;
+    checked_count += pDest->GetCount();
+    if (!checked_count.IsValid() || index >= checked_count.ValueOrDie())
+      return nullptr;
+
     index -= count;
-    FX_POSITION pos = pDest->GetStartPos();
     int i = 0;
-    while (pos) {
-      pDestObj = pDest->GetNextElement(pos, bsName);
+    for (const auto& it : *pDest) {
+      bsName = it.first;
+      pDestObj = it.second;
       if (!pDestObj)
         continue;
       if (i == index)
         break;
       i++;
     }
   } else {
     pDestObj = nameTree.LookupValue(index, bsName);
   }
   if (!pDestObj)
@@ skipping 12 matching lines @@
   if (!buffer) {
     *buflen = len;
   } else if (*buflen >= len) {
     memcpy(buffer, utf16Name.c_str(), len);
     *buflen = len;
   } else {
     *buflen = -1;
   }
   return (FPDF_DEST)pDestObj;
 }