Introduce CPDFPageFromFPDFPage()

fpdfsdk/src/fpdfdoc.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/fpdf_doc.h"
 #include "../include/fsdk_define.h"
 
 namespace {
@@ skipping 183 matching lines @@
     return 0;
   CPDF_Document* pDoc = CPDFDocumentFromFPDFDocument(document);
   if (!pDoc)
     return 0;
   CPDF_Dest dest((CPDF_Array*)pDict);
   return dest.GetPageIndex(pDoc);
 }
 
 DLLEXPORT FPDF_LINK STDCALL
 FPDFLink_GetLinkAtPoint(FPDF_PAGE page, double x, double y) {
-  CPDF_Page* pPage = (CPDF_Page*)page;
+  CPDF_Page* pPage = CPDFPageFromFPDFPage(page);
+  if (!pPage)
+    return nullptr;
+
   CPDF_LinkList* pLinkList = GetLinkList(pPage);
   if (!pLinkList)
     return nullptr;
 
   return pLinkList->GetLinkAtPoint(pPage, (FX_FLOAT)x, (FX_FLOAT)y, nullptr)
       .GetDict();
 }
 
 DLLEXPORT int STDCALL
 FPDFLink_GetLinkZOrderAtPoint(FPDF_PAGE page, double x, double y) {
-  CPDF_Page* pPage = (CPDF_Page*)page;
+  CPDF_Page* pPage = CPDFPageFromFPDFPage(page);
+  if (!pPage)
+    return -1;
+
   CPDF_LinkList* pLinkList = GetLinkList(pPage);
   if (!pLinkList)
     return -1;
 
   int z_order = -1;
   pLinkList->GetLinkAtPoint(pPage, (FX_FLOAT)x, (FX_FLOAT)y, &z_order);
   return z_order;
 }
 
 DLLEXPORT FPDF_DEST STDCALL FPDFLink_GetDest(FPDF_DOCUMENT document,
@@ skipping 18 matching lines @@
   if (!pDict)
     return nullptr;
 
   CPDF_Link link((CPDF_Dictionary*)pDict);
   return link.GetAction().GetDict();
 }
 
 DLLEXPORT FPDF_BOOL STDCALL FPDFLink_Enumerate(FPDF_PAGE page,
                                                int* startPos,
                                                FPDF_LINK* linkAnnot) {
-  if (!page || !startPos || !linkAnnot)
+  if (!startPos || !linkAnnot)
     return FALSE;
-  CPDF_Page* pPage = (CPDF_Page*)page;
-  if (!pPage->m_pFormDict)
+  CPDF_Page* pPage = CPDFPageFromFPDFPage(page);
+  if (!pPage || !pPage->m_pFormDict)
     return FALSE;
   CPDF_Array* pAnnots = pPage->m_pFormDict->GetArray("Annots");
   if (!pAnnots)
     return FALSE;
   for (int i = *startPos; i < (int)pAnnots->GetCount(); i++) {
     CPDF_Dictionary* pDict = (CPDF_Dictionary*)pAnnots->GetElementValue(i);
     if (!pDict || pDict->GetType() != PDFOBJ_DICTIONARY)
       continue;
     if (pDict->GetString(FX_BSTRC("Subtype")).Equal(FX_BSTRC("Link"))) {
       *startPos = i + 1;
@@ skipping 65 matching lines @@
     return 0;
   CFX_WideString text = pInfo->GetUnicodeText(tag);
   // Use UTF-16LE encoding
   CFX_ByteString encodedText = text.UTF16LE_Encode();
   unsigned long len = encodedText.GetLength();
   if (buffer && buflen >= len) {
     FXSYS_memcpy(buffer, encodedText.c_str(), len);
   }
   return len;
 }