Add type cast definitions for CPDF_Array.

This Cl adds ToArray, CPDF_Object::AsArray and CPDF_Object::IsArray and
updates the src to use them as needed.

BUG=pdfium:201
R=thestig@chromium.org, tsepez@chromium.org

Review URL: https://codereview.chromium.org/1417893003 .

18 files changed, 120 insertions, 148 deletions

diff --git a/core/src/fpdfapi/fpdf_edit/fpdf_edit_content.cpp b/core/src/fpdfapi/fpdf_edit/fpdf_edit_content.cpp
index 79bfbdb13a..32802d0001 100644
--- a/core/src/fpdfapi/fpdf_edit/fpdf_edit_content.cpp
+++ b/core/src/fpdfapi/fpdf_edit/fpdf_edit_content.cpp
@@ -120,13 +120,11 @@ void CPDF_PageContentGenerate::ProcessForm(CFX_ByteTextBuf& buf,
 void CPDF_PageContentGenerate::TransformContent(CFX_Matrix& matrix) {
   CPDF_Dictionary* pDict = m_pPage->m_pFormDict;
   CPDF_Object* pContent = pDict ? pDict->GetElementValue("Contents") : NULL;
-  if (!pContent) {
+  if (!pContent)
     return;
-  }
+
   CFX_ByteTextBuf buf;
-  int type = pContent->GetType();
-  if (type == PDFOBJ_ARRAY) {
-    CPDF_Array* pArray = (CPDF_Array*)pContent;
+  if (CPDF_Array* pArray = pContent->AsArray()) {
     int iCount = pArray->GetCount();
     CPDF_StreamAcc** pContentArray = FX_Alloc(CPDF_StreamAcc*, iCount);
     int size = 0;
@@ -153,7 +151,7 @@ void CPDF_PageContentGenerate::TransformContent(CFX_Matrix& matrix) {
     ProcessForm(buf, pBuf, size, matrix);
     FX_Free(pBuf);
     FX_Free(pContentArray);
-  } else if (type == PDFOBJ_STREAM) {
+  } else if (pContent->GetType() == PDFOBJ_STREAM) {
     CPDF_StreamAcc contentStream;
     contentStream.LoadAllData((CPDF_Stream*)pContent);
     ProcessForm(buf, contentStream.GetData(), contentStream.GetSize(), matrix);
diff --git a/core/src/fpdfapi/fpdf_edit/fpdf_edit_create.cpp b/core/src/fpdfapi/fpdf_edit/fpdf_edit_create.cpp
index b097389160..d6522158f1 100644
--- a/core/src/fpdfapi/fpdf_edit/fpdf_edit_create.cpp
+++ b/core/src/fpdfapi/fpdf_edit/fpdf_edit_create.cpp
@@ -79,7 +79,7 @@ int32_t PDF_CreatorAppendObject(const CPDF_Object* pObj,
         return -1;
       }
       offset += 1;
-      CPDF_Array* p = (CPDF_Array*)pObj;
+      const CPDF_Array* p = pObj->AsArray();
       for (FX_DWORD i = 0; i < p->GetCount(); i++) {
         CPDF_Object* pElement = p->GetElement(i);
         if (pElement->GetObjNum()) {
@@ -1195,7 +1195,7 @@ int32_t CPDF_Creator::WriteDirectObj(FX_DWORD objnum,
         return -1;
       }
       m_Offset += 1;
-      CPDF_Array* p = (CPDF_Array*)pObj;
+      const CPDF_Array* p = pObj->AsArray();
       for (FX_DWORD i = 0; i < p->GetCount(); i++) {
         CPDF_Object* pElement = p->GetElement(i);
         if (pElement->GetObjNum()) {
diff --git a/core/src/fpdfapi/fpdf_font/fpdf_font_cid.cpp b/core/src/fpdfapi/fpdf_font/fpdf_font_cid.cpp
index 6ccc4a345b..8972201b66 100644
--- a/core/src/fpdfapi/fpdf_font/fpdf_font_cid.cpp
+++ b/core/src/fpdfapi/fpdf_font/fpdf_font_cid.cpp
@@ -1664,14 +1664,13 @@ void CPDF_CIDFont::LoadMetricsArray(CPDF_Array* pArray,
   FX_DWORD count = pArray->GetCount();
   for (FX_DWORD i = 0; i < count; i++) {
     CPDF_Object* pObj = pArray->GetElementValue(i);
-    if (pObj == NULL) {
+    if (!pObj)
       continue;
-    }
-    if (pObj->GetType() == PDFOBJ_ARRAY) {
-      if (width_status != 1) {
+
+    if (CPDF_Array* pArray = pObj->AsArray()) {
+      if (width_status != 1)
         return;
-      }
-      CPDF_Array* pArray = (CPDF_Array*)pObj;
+
       FX_DWORD count = pArray->GetCount();
       for (FX_DWORD j = 0; j < count; j += nElements) {
         result.Add(first_code);
diff --git a/core/src/fpdfapi/fpdf_page/fpdf_page.cpp b/core/src/fpdfapi/fpdf_page/fpdf_page.cpp
index f6f03336a0..162acfa898 100644
--- a/core/src/fpdfapi/fpdf_page/fpdf_page.cpp
+++ b/core/src/fpdfapi/fpdf_page/fpdf_page.cpp
@@ -814,8 +814,7 @@ void CPDF_Page::Load(CPDF_Document* pDocument,
   if (rotate < 0) {
     rotate += 4;
   }
-  CPDF_Array *pMediaBox, *pCropBox;
-  pMediaBox = (CPDF_Array*)GetPageAttr(FX_BSTRC("MediaBox"));
+  CPDF_Array* pMediaBox = ToArray(GetPageAttr(FX_BSTRC("MediaBox")));
   CFX_FloatRect mediabox;
   if (pMediaBox) {
     mediabox = pMediaBox->GetRect();
@@ -824,7 +823,8 @@ void CPDF_Page::Load(CPDF_Document* pDocument,
   if (mediabox.IsEmpty()) {
     mediabox = CFX_FloatRect(0, 0, 612, 792);
   }
-  pCropBox = (CPDF_Array*)GetPageAttr(FX_BSTRC("CropBox"));
+
+  CPDF_Array* pCropBox = ToArray(GetPageAttr(FX_BSTRC("CropBox")));
   if (pCropBox) {
     m_BBox = pCropBox->GetRect();
     m_BBox.Normalize();
diff --git a/core/src/fpdfapi/fpdf_page/fpdf_page_colors.cpp b/core/src/fpdfapi/fpdf_page/fpdf_page_colors.cpp
index 73b1091856..4f54c01ce7 100644
--- a/core/src/fpdfapi/fpdf_page/fpdf_page_colors.cpp
+++ b/core/src/fpdfapi/fpdf_page/fpdf_page_colors.cpp
@@ -1139,14 +1139,11 @@ void CPDF_DeviceNCS::GetDefaultValue(int iComponent,
   max = 1.0f;
 }
 FX_BOOL CPDF_DeviceNCS::v_Load(CPDF_Document* pDoc, CPDF_Array* pArray) {
-  CPDF_Object* pObj = pArray->GetElementValue(1);
-  if (!pObj) {
-    return FALSE;
-  }
-  if (pObj->GetType() != PDFOBJ_ARRAY) {
+  CPDF_Array* pObj = ToArray(pArray->GetElementValue(1));
+  if (!pObj)
     return FALSE;
-  }
-  m_nComponents = ((CPDF_Array*)pObj)->GetCount();
+
+  m_nComponents = pObj->GetCount();
   CPDF_Object* pAltCS = pArray->GetElementValue(2);
   if (!pAltCS || pAltCS == m_pArray) {
     return FALSE;
@@ -1224,21 +1221,19 @@ CPDF_ColorSpace* CPDF_ColorSpace::Load(CPDF_Document* pDoc, CPDF_Object* pObj) {
     }
     return nullptr;
   }
-  if (pObj->GetType() != PDFOBJ_ARRAY) {
-    return NULL;
-  }
-  CPDF_Array* pArray = (CPDF_Array*)pObj;
-  if (pArray->GetCount() == 0) {
-    return NULL;
-  }
+
+  CPDF_Array* pArray = pObj->AsArray();
+  if (!pArray || pArray->GetCount() == 0)
+    return nullptr;
+
   CPDF_Object* pFamilyObj = pArray->GetElementValue(0);
-  if (!pFamilyObj) {
-    return NULL;
-  }
+  if (!pFamilyObj)
+    return nullptr;
+
   CFX_ByteString familyname = pFamilyObj->GetString();
-  if (pArray->GetCount() == 1) {
+  if (pArray->GetCount() == 1)
     return _CSFromName(familyname);
-  }
+
   CPDF_ColorSpace* pCS = NULL;
   FX_DWORD id = familyname.GetID();
   if (id == FXBSTR_ID('C', 'a', 'l', 'G')) {
diff --git a/core/src/fpdfapi/fpdf_page/fpdf_page_doc.cpp b/core/src/fpdfapi/fpdf_page/fpdf_page_doc.cpp
index 9a1d48a416..436cca6d99 100644
--- a/core/src/fpdfapi/fpdf_page/fpdf_page_doc.cpp
+++ b/core/src/fpdfapi/fpdf_page/fpdf_page_doc.cpp
@@ -343,10 +343,8 @@ CPDF_ColorSpace* CPDF_DocPageData::GetColorSpace(CPDF_Object* pCSObj,
     return pDefaultCS ? GetColorSpace(pDefaultCS, nullptr) : pCS;
   }
 
-  if (pCSObj->GetType() != PDFOBJ_ARRAY)
-    return nullptr;
-  CPDF_Array* pArray = (CPDF_Array*)pCSObj;
-  if (pArray->GetCount() == 0)
+  CPDF_Array* pArray = pCSObj->AsArray();
+  if (!pArray || pArray->GetCount() == 0)
     return nullptr;
   if (pArray->GetCount() == 1)
     return GetColorSpace(pArray->GetElementValue(0), pResources);
diff --git a/core/src/fpdfapi/fpdf_page/fpdf_page_graph_state.cpp b/core/src/fpdfapi/fpdf_page/fpdf_page_graph_state.cpp
index 62a3c67996..78d3d26188 100644
--- a/core/src/fpdfapi/fpdf_page/fpdf_page_graph_state.cpp
+++ b/core/src/fpdfapi/fpdf_page/fpdf_page_graph_state.cpp
@@ -461,10 +461,10 @@ void CPDF_AllStates::ProcessExtGS(CPDF_Dictionary* pGS,
   while (pos) {
     CFX_ByteString key_str;
     CPDF_Object* pElement = pGS->GetNextElement(pos, key_str);
-    CPDF_Object* pObject = pElement ? pElement->GetDirect() : NULL;
-    if (pObject == NULL) {
+    CPDF_Object* pObject = pElement ? pElement->GetDirect() : nullptr;
+    if (!pObject)
       continue;
-    }
+
     FX_DWORD key = key_str.GetID();
     switch (key) {
       case FXBSTR_ID('L', 'W', 0, 0):
@@ -482,14 +482,14 @@ void CPDF_AllStates::ProcessExtGS(CPDF_Dictionary* pGS,
         m_GraphState.GetModify()->m_MiterLimit = pObject->GetNumber();
         break;
       case FXBSTR_ID('D', 0, 0, 0): {
-        if (pObject->GetType() != PDFOBJ_ARRAY) {
+        CPDF_Array* pDash = pObject->AsArray();
+        if (!pDash)
           break;
-        }
-        CPDF_Array* pDash = (CPDF_Array*)pObject;
+
         CPDF_Array* pArray = pDash->GetArray(0);
-        if (pArray == NULL) {
+        if (!pArray)
           break;
-        }
+
         SetLineDash(pArray, pDash->GetNumber(1), 1.0f);
         break;
       }
@@ -497,10 +497,10 @@ void CPDF_AllStates::ProcessExtGS(CPDF_Dictionary* pGS,
         m_GeneralState.SetRenderIntent(pObject->GetString());
         break;
       case FXBSTR_ID('F', 'o', 'n', 't'): {
-        if (pObject->GetType() != PDFOBJ_ARRAY) {
+        CPDF_Array* pFont = pObject->AsArray();
+        if (!pFont)
           break;
-        }
-        CPDF_Array* pFont = (CPDF_Array*)pObject;
+
         m_TextState.GetModify()->m_FontSize = pFont->GetNumber(1);
         m_TextState.SetFont(pParser->FindFont(pFont->GetString(0)));
         break;
@@ -514,12 +514,10 @@ void CPDF_AllStates::ProcessExtGS(CPDF_Dictionary* pGS,
             (pObject && !pObject->IsName()) ? pObject : nullptr;
         break;
       case FXBSTR_ID('B', 'M', 0, 0): {
-        CFX_ByteString mode;
-        if (pObject->GetType() == PDFOBJ_ARRAY) {
-          mode = ((CPDF_Array*)pObject)->GetString(0);
-        } else {
-          mode = pObject->GetString();
-        }
+        CPDF_Array* pArray = pObject->AsArray();
+        CFX_ByteString mode =
+            pArray ? pArray->GetString(0) : pObject->GetString();
+
         pGeneralState->SetBlendMode(mode);
         if (pGeneralState->m_BlendType > FXDIB_BLEND_MULTIPLY) {
           pParser->GetObjectList()->m_bBackgroundAlphaNeeded = TRUE;
diff --git a/core/src/fpdfapi/fpdf_page/fpdf_page_parser.cpp b/core/src/fpdfapi/fpdf_page/fpdf_page_parser.cpp
index 6f186e6c3b..7aa2cf8aa3 100644
--- a/core/src/fpdfapi/fpdf_page/fpdf_page_parser.cpp
+++ b/core/src/fpdfapi/fpdf_page/fpdf_page_parser.cpp
@@ -514,7 +514,7 @@ void _PDF_ReplaceAbbr(CPDF_Object* pObj) {
       break;
     }
     case PDFOBJ_ARRAY: {
-      CPDF_Array* pArray = (CPDF_Array*)pObj;
+      CPDF_Array* pArray = pObj->AsArray();
       for (FX_DWORD i = 0; i < pArray->GetCount(); i++) {
         CPDF_Object* pElement = pArray->GetElement(i);
         if (pElement->IsName()) {
@@ -577,7 +577,7 @@ void _PDF_ReplaceFull(CPDF_Object* pObj) {
       break;
     }
     case PDFOBJ_ARRAY: {
-      CPDF_Array* pArray = (CPDF_Array*)pObj;
+      CPDF_Array* pArray = pObj->AsArray();
       for (FX_DWORD i = 0; i < pArray->GetCount(); i++) {
         CPDF_Object* pElement = pArray->GetElement(i);
         if (pElement->IsName()) {
diff --git a/core/src/fpdfapi/fpdf_page/fpdf_page_parser_old.cpp b/core/src/fpdfapi/fpdf_page/fpdf_page_parser_old.cpp
index f051d0db5a..c27ede44cb 100644
--- a/core/src/fpdfapi/fpdf_page/fpdf_page_parser_old.cpp
+++ b/core/src/fpdfapi/fpdf_page/fpdf_page_parser_old.cpp
@@ -332,16 +332,16 @@ CPDF_Stream* CPDF_StreamParser::ReadInlineStream(CPDF_Document* pDoc,
   CFX_ByteString Decoder;
   CPDF_Dictionary* pParam = NULL;
   CPDF_Object* pFilter = pDict->GetElementValue(FX_BSTRC("Filter"));
-  if (pFilter == NULL) {
-  } else if (pFilter->GetType() == PDFOBJ_ARRAY) {
-    Decoder = ((CPDF_Array*)pFilter)->GetString(0);
-    CPDF_Array* pParams = pDict->GetArray(FX_BSTRC("DecodeParms"));
-    if (pParams) {
-      pParam = pParams->GetDict(0);
+  if (pFilter) {
+    if (CPDF_Array* pArray = pFilter->AsArray()) {
+      Decoder = pArray->GetString(0);
+      CPDF_Array* pParams = pDict->GetArray(FX_BSTRC("DecodeParms"));
+      if (pParams)
+        pParam = pParams->GetDict(0);
+    } else {
+      Decoder = pFilter->GetString();
+      pParam = pDict->GetDict(FX_BSTRC("DecodeParms"));
     }
-  } else {
-    Decoder = pFilter->GetString();
-    pParam = pDict->GetDict(FX_BSTRC("DecodeParms"));
   }
   FX_DWORD width = pDict->GetInteger(FX_BSTRC("Width"));
   FX_DWORD height = pDict->GetInteger(FX_BSTRC("Height"));
@@ -403,12 +403,11 @@ CPDF_Stream* CPDF_StreamParser::ReadInlineStream(CPDF_Document* pDoc,
     if (bDecode) {
       m_Pos += dwStreamSize;
       dwStreamSize = dwDestSize;
-      if (pFilter->GetType() == PDFOBJ_ARRAY) {
-        ((CPDF_Array*)pFilter)->RemoveAt(0);
+      if (CPDF_Array* pArray = pFilter->AsArray()) {
+        pArray->RemoveAt(0);
         CPDF_Array* pParams = pDict->GetArray(FX_BSTRC("DecodeParms"));
-        if (pParams) {
+        if (pParams)
           pParams->RemoveAt(0);
-        }
       } else {
         pDict->RemoveAt(FX_BSTRC("Filter"));
         pDict->RemoveAt(FX_BSTRC("DecodeParms"));
@@ -965,8 +964,7 @@ void CPDF_ContentParser::Start(CPDF_Page* pPage, CPDF_ParseOptions* pOptions) {
     m_nStreams = 0;
     m_pSingleStream = new CPDF_StreamAcc;
     m_pSingleStream->LoadAllData((CPDF_Stream*)pContent, FALSE);
-  } else if (pContent->GetType() == PDFOBJ_ARRAY) {
-    CPDF_Array* pArray = (CPDF_Array*)pContent;
+  } else if (CPDF_Array* pArray = pContent->AsArray()) {
     m_nStreams = pArray->GetCount();
     if (m_nStreams == 0) {
       m_Status = Done;
diff --git a/core/src/fpdfapi/fpdf_page/fpdf_page_pattern.cpp b/core/src/fpdfapi/fpdf_page/fpdf_page_pattern.cpp
index 3f915a7b79..a73bdc9e8e 100644
--- a/core/src/fpdfapi/fpdf_page/fpdf_page_pattern.cpp
+++ b/core/src/fpdfapi/fpdf_page/fpdf_page_pattern.cpp
@@ -118,14 +118,11 @@ FX_BOOL CPDF_ShadingPattern::Load() {
   }
   CPDF_Object* pFunc = pShadingDict->GetElementValue(FX_BSTRC("Function"));
   if (pFunc) {
-    if (pFunc->GetType() == PDFOBJ_ARRAY) {
-      m_nFuncs = ((CPDF_Array*)pFunc)->GetCount();
-      if (m_nFuncs > 4) {
-        m_nFuncs = 4;
-      }
+    if (CPDF_Array* pArray = pFunc->AsArray()) {
+      m_nFuncs = std::min<int>(pArray->GetCount(), 4);
+
       for (int i = 0; i < m_nFuncs; i++) {
-        m_pFunctions[i] =
-            CPDF_Function::Load(((CPDF_Array*)pFunc)->GetElementValue(i));
+        m_pFunctions[i] = CPDF_Function::Load(pArray->GetElementValue(i));
       }
     } else {
       m_pFunctions[0] = CPDF_Function::Load(pFunc);
diff --git a/core/src/fpdfapi/fpdf_parser/fpdf_parser_decode.cpp b/core/src/fpdfapi/fpdf_parser/fpdf_parser_decode.cpp
index cbbfbd7197..1815d40194 100644
--- a/core/src/fpdfapi/fpdf_parser/fpdf_parser_decode.cpp
+++ b/core/src/fpdfapi/fpdf_parser/fpdf_parser_decode.cpp
@@ -331,31 +331,27 @@ FX_BOOL PDF_DataDecode(const uint8_t* src_buf,
 
 {
   CPDF_Object* pDecoder =
-      pDict ? pDict->GetElementValue(FX_BSTRC("Filter")) : NULL;
-  if (!pDecoder || (pDecoder->GetType() != PDFOBJ_ARRAY && !pDecoder->IsName()))
+      pDict ? pDict->GetElementValue(FX_BSTRC("Filter")) : nullptr;
+  if (!pDecoder || (!pDecoder->IsArray() && !pDecoder->IsName()))
     return FALSE;
 
   CPDF_Object* pParams =
-      pDict ? pDict->GetElementValue(FX_BSTRC("DecodeParms")) : NULL;
+      pDict ? pDict->GetElementValue(FX_BSTRC("DecodeParms")) : nullptr;
   CFX_ByteStringArray DecoderList;
   CFX_PtrArray ParamList;
-  if (pDecoder->GetType() == PDFOBJ_ARRAY) {
-    if (pParams && pParams->GetType() != PDFOBJ_ARRAY) {
-      pParams = NULL;
-    }
-    CPDF_Array* pDecoders = (CPDF_Array*)pDecoder;
+  if (CPDF_Array* pDecoders = pDecoder->AsArray()) {
+    CPDF_Array* pParamsArray = ToArray(pParams);
+    if (!pParamsArray)
+      pParams = nullptr;
+
     for (FX_DWORD i = 0; i < pDecoders->GetCount(); i++) {
       CFX_ByteStringC str = pDecoders->GetConstString(i);
       DecoderList.Add(str);
-      if (pParams) {
-        ParamList.Add(((CPDF_Array*)pParams)->GetDict(i));
-      } else {
-        ParamList.Add(NULL);
-      }
+      ParamList.Add(pParams ? pParamsArray->GetDict(i) : nullptr);
     }
   } else {
     DecoderList.Add(pDecoder->GetConstString());
-    ParamList.Add(pParams ? pParams->GetDict() : NULL);
+    ParamList.Add(pParams ? pParams->GetDict() : nullptr);
   }
   uint8_t* last_buf = (uint8_t*)src_buf;
   FX_DWORD last_size = src_size;
diff --git a/core/src/fpdfapi/fpdf_parser/fpdf_parser_document.cpp b/core/src/fpdfapi/fpdf_parser/fpdf_parser_document.cpp
index 3d9900deac..2396261276 100644
--- a/core/src/fpdfapi/fpdf_parser/fpdf_parser_document.cpp
+++ b/core/src/fpdfapi/fpdf_parser/fpdf_parser_document.cpp
@@ -306,7 +306,7 @@ FX_BOOL CPDF_Document::IsContentUsedElsewhere(FX_DWORD objnum,
       continue;
     }
     if (pContents->GetDirectType() == PDFOBJ_ARRAY) {
-      CPDF_Array* pArray = (CPDF_Array*)pContents->GetDirect();
+      CPDF_Array* pArray = pContents->GetDirect()->AsArray();
       for (FX_DWORD j = 0; j < pArray->GetCount(); j++) {
         CPDF_Object* pRef = pArray->GetElement(j);
         if (pRef == NULL || pRef->GetType() != PDFOBJ_REFERENCE) {
diff --git a/core/src/fpdfapi/fpdf_parser/fpdf_parser_objects.cpp b/core/src/fpdfapi/fpdf_parser/fpdf_parser_objects.cpp
index e3d9cd7291..6a090ce64d 100644
--- a/core/src/fpdfapi/fpdf_parser/fpdf_parser_objects.cpp
+++ b/core/src/fpdfapi/fpdf_parser/fpdf_parser_objects.cpp
@@ -25,7 +25,7 @@ void CPDF_Object::Destroy() {
       delete AsName();
       break;
     case PDFOBJ_ARRAY:
-      delete (CPDF_Array*)this;
+      delete AsArray();
       break;
     case PDFOBJ_DICTIONARY:
       delete AsDictionary();
@@ -161,10 +161,9 @@ CPDF_Dictionary* CPDF_Object::GetDict() const {
 }
 
 CPDF_Array* CPDF_Object::GetArray() const {
-  if (m_Type == PDFOBJ_ARRAY)
-    return (CPDF_Array*)this;
-
-  return NULL;
+  // The method should be made non-const if we want to not be const.
+  // See bug #234.
+  return const_cast<CPDF_Array*>(AsArray());
 }
 void CPDF_Object::SetString(const CFX_ByteString& str) {
   ASSERT(this != NULL);
@@ -217,7 +216,7 @@ FX_BOOL CPDF_Object::IsIdentical(CPDF_Object* pOther) const {
     case PDFOBJ_NAME:
       return AsName()->Identical(pOther->AsName());
     case PDFOBJ_ARRAY:
-      return (((CPDF_Array*)this)->Identical((CPDF_Array*)pOther));
+      return AsArray()->Identical(pOther->AsArray());
     case PDFOBJ_DICTIONARY:
       return AsDictionary()->Identical(pOther->AsDictionary());
     case PDFOBJ_NULL:
@@ -261,7 +260,7 @@ CPDF_Object* CPDF_Object::CloneInternal(FX_BOOL bDirect,
       return new CPDF_Name(AsName()->m_Name);
     case PDFOBJ_ARRAY: {
       CPDF_Array* pCopy = new CPDF_Array();
-      CPDF_Array* pThis = (CPDF_Array*)this;
+      const CPDF_Array* pThis = AsArray();
       int n = pThis->GetCount();
       for (int i = 0; i < n; i++) {
         CPDF_Object* value = (CPDF_Object*)pThis->m_Objects.GetAt(i);
@@ -341,6 +340,14 @@ void CPDF_Object::SetUnicodeText(const FX_WCHAR* pUnicodes, int len) {
   }
 }
 
+CPDF_Array* CPDF_Object::AsArray() {
+  return IsArray() ? static_cast<CPDF_Array*>(this) : nullptr;
+}
+
+const CPDF_Array* CPDF_Object::AsArray() const {
+  return IsArray() ? static_cast<const CPDF_Array*>(this) : nullptr;
+}
+
 CPDF_Boolean* CPDF_Object::AsBoolean() {
   return IsBoolean() ? static_cast<CPDF_Boolean*>(this) : nullptr;
 }
@@ -420,9 +427,9 @@ CPDF_Array::~CPDF_Array() {
 }
 CFX_FloatRect CPDF_Array::GetRect() {
   CFX_FloatRect rect;
-  if (m_Type != PDFOBJ_ARRAY || m_Objects.GetSize() != 4) {
+  if (!IsArray() || m_Objects.GetSize() != 4)
     return rect;
-  }
+
   rect.left = GetNumber(0);
   rect.bottom = GetNumber(1);
   rect.right = GetNumber(2);
@@ -431,9 +438,9 @@ CFX_FloatRect CPDF_Array::GetRect() {
 }
 CFX_AffineMatrix CPDF_Array::GetMatrix() {
   CFX_AffineMatrix matrix;
-  if (m_Type != PDFOBJ_ARRAY || m_Objects.GetSize() != 6) {
+  if (!IsArray() || m_Objects.GetSize() != 6)
     return matrix;
-  }
+
   matrix.Set(GetNumber(0), GetNumber(1), GetNumber(2), GetNumber(3),
              GetNumber(4), GetNumber(5));
   return matrix;
@@ -499,14 +506,10 @@ CPDF_Stream* CPDF_Array::GetStream(FX_DWORD i) const {
   return (CPDF_Stream*)p;
 }
 CPDF_Array* CPDF_Array::GetArray(FX_DWORD i) const {
-  CPDF_Object* p = GetElementValue(i);
-  if (p == NULL || p->GetType() != PDFOBJ_ARRAY) {
-    return NULL;
-  }
-  return (CPDF_Array*)p;
+  return ToArray(GetElementValue(i));
 }
 void CPDF_Array::RemoveAt(FX_DWORD i) {
-  ASSERT(m_Type == PDFOBJ_ARRAY);
+  ASSERT(IsArray());
   if (i >= (FX_DWORD)m_Objects.GetSize()) {
     return;
   }
@@ -518,7 +521,7 @@ void CPDF_Array::RemoveAt(FX_DWORD i) {
 void CPDF_Array::SetAt(FX_DWORD i,
                        CPDF_Object* pObj,
                        CPDF_IndirectObjects* pObjs) {
-  ASSERT(m_Type == PDFOBJ_ARRAY);
+  ASSERT(IsArray());
   ASSERT(i < (FX_DWORD)m_Objects.GetSize());
   if (i >= (FX_DWORD)m_Objects.GetSize()) {
     return;
@@ -551,25 +554,25 @@ void CPDF_Array::Add(CPDF_Object* pObj, CPDF_IndirectObjects* pObjs) {
   m_Objects.Add(pObj);
 }
 void CPDF_Array::AddName(const CFX_ByteString& str) {
-  ASSERT(m_Type == PDFOBJ_ARRAY);
+  ASSERT(IsArray());
   Add(new CPDF_Name(str));
 }
 void CPDF_Array::AddString(const CFX_ByteString& str) {
-  ASSERT(m_Type == PDFOBJ_ARRAY);
+  ASSERT(IsArray());
   Add(new CPDF_String(str));
 }
 void CPDF_Array::AddInteger(int i) {
-  ASSERT(m_Type == PDFOBJ_ARRAY);
+  ASSERT(IsArray());
   Add(new CPDF_Number(i));
 }
 void CPDF_Array::AddNumber(FX_FLOAT f) {
-  ASSERT(m_Type == PDFOBJ_ARRAY);
+  ASSERT(IsArray());
   CPDF_Number* pNumber = new CPDF_Number;
   pNumber->SetNumber(f);
   Add(pNumber);
 }
 void CPDF_Array::AddReference(CPDF_IndirectObjects* pDoc, FX_DWORD objnum) {
-  ASSERT(m_Type == PDFOBJ_ARRAY);
+  ASSERT(IsArray());
   Add(new CPDF_Reference(pDoc, objnum));
 }
 FX_BOOL CPDF_Array::Identical(CPDF_Array* pOther) const {
@@ -712,11 +715,7 @@ CPDF_Dictionary* CPDF_Dictionary::GetDict(const CFX_ByteStringC& key) const {
   return nullptr;
 }
 CPDF_Array* CPDF_Dictionary::GetArray(const CFX_ByteStringC& key) const {
-  CPDF_Object* p = GetElementValue(key);
-  if (p == NULL || p->GetType() != PDFOBJ_ARRAY) {
-    return NULL;
-  }
-  return (CPDF_Array*)p;
+  return ToArray(GetElementValue(key));
 }
 CPDF_Stream* CPDF_Dictionary::GetStream(const CFX_ByteStringC& key) const {
   CPDF_Object* p = GetElementValue(key);
diff --git a/core/src/fpdfapi/fpdf_parser/fpdf_parser_parser.cpp b/core/src/fpdfapi/fpdf_parser/fpdf_parser_parser.cpp
index 514380eeab..8b822a8b9c 100644
--- a/core/src/fpdfapi/fpdf_parser/fpdf_parser_parser.cpp
+++ b/core/src/fpdfapi/fpdf_parser/fpdf_parser_parser.cpp
@@ -1154,17 +1154,14 @@ FX_BOOL CPDF_Parser::LoadCrossRefV5(FX_FILESIZE pos,
 }
 CPDF_Array* CPDF_Parser::GetIDArray() {
   CPDF_Object* pID = m_pTrailer ? m_pTrailer->GetElement(FX_BSTRC("ID")) : NULL;
-  if (pID == NULL) {
-    return NULL;
-  }
+  if (!pID)
+    return nullptr;
+
   if (pID->GetType() == PDFOBJ_REFERENCE) {
     pID = ParseIndirectObject(NULL, ((CPDF_Reference*)pID)->GetRefObjNum());
     m_pTrailer->SetAt(FX_BSTRC("ID"), pID);
   }
-  if (pID == NULL || pID->GetType() != PDFOBJ_ARRAY) {
-    return NULL;
-  }
-  return (CPDF_Array*)pID;
+  return ToArray(pID);
 }
 FX_DWORD CPDF_Parser::GetRootObjNum() {
   CPDF_Object* pRef =
@@ -3474,7 +3471,7 @@ FX_BOOL CPDF_DataAvail::CheckPage(IFX_DownloadHints* pHints) {
       }
       continue;
     }
-    if (pObj->GetType() == PDFOBJ_ARRAY) {
+    if (pObj->IsArray()) {
       CPDF_Array* pArray = pObj->GetArray();
       if (pArray) {
         int32_t iSize = pArray->GetCount();
@@ -3543,7 +3540,7 @@ FX_BOOL CPDF_DataAvail::GetPageKids(CPDF_Parser* pParser, CPDF_Object* pPages) {
       m_PageObjList.Add(pKid->GetRefObjNum());
     } break;
     case PDFOBJ_ARRAY: {
-      CPDF_Array* pKidsArray = (CPDF_Array*)pKids;
+      CPDF_Array* pKidsArray = pKids->AsArray();
       for (FX_DWORD i = 0; i < pKidsArray->GetCount(); ++i) {
         CPDF_Object* pKid = (CPDF_Object*)pKidsArray->GetElement(i);
         if (pKid && pKid->GetType() == PDFOBJ_REFERENCE) {
@@ -4116,13 +4113,15 @@ FX_BOOL CPDF_DataAvail::CheckArrayPageNode(FX_DWORD dwPageNo,
     }
     return FALSE;
   }
-  if (pPages->GetType() != PDFOBJ_ARRAY) {
+
+  CPDF_Array* pArray = pPages->AsArray();
+  if (!pArray) {
     pPages->Release();
     m_docStatus = PDF_DATAAVAIL_ERROR;
     return FALSE;
   }
+
   pPageNode->m_type = PDF_PAGENODE_PAGES;
-  CPDF_Array* pArray = (CPDF_Array*)pPages;
   for (FX_DWORD i = 0; i < pArray->GetCount(); ++i) {
     CPDF_Object* pKid = (CPDF_Object*)pArray->GetElement(i);
     if (!pKid || pKid->GetType() != PDFOBJ_REFERENCE) {
@@ -4151,7 +4150,7 @@ FX_BOOL CPDF_DataAvail::CheckUnkownPageNode(FX_DWORD dwPageNo,
     }
     return FALSE;
   }
-  if (pPage->GetType() == PDFOBJ_ARRAY) {
+  if (pPage->IsArray()) {
     pPageNode->m_dwPageNo = dwPageNo;
     pPageNode->m_type = PDF_PAGENODE_ARRAY;
     pPage->Release();
@@ -4180,7 +4179,7 @@ FX_BOOL CPDF_DataAvail::CheckUnkownPageNode(FX_DWORD dwPageNo,
         pNode->m_dwPageNo = pKid->GetRefObjNum();
       } break;
       case PDFOBJ_ARRAY: {
-        CPDF_Array* pKidsArray = (CPDF_Array*)pKids;
+        CPDF_Array* pKidsArray = pKids->AsArray();
         for (FX_DWORD i = 0; i < pKidsArray->GetCount(); ++i) {
           CPDF_Object* pKid = (CPDF_Object*)pKidsArray->GetElement(i);
           if (!pKid || pKid->GetType() != PDFOBJ_REFERENCE) {
diff --git a/core/src/fpdfapi/fpdf_parser/fpdf_parser_utility.cpp b/core/src/fpdfapi/fpdf_parser/fpdf_parser_utility.cpp
index 2c161a7dd4..a2d65fa4bd 100644
--- a/core/src/fpdfapi/fpdf_parser/fpdf_parser_utility.cpp
+++ b/core/src/fpdfapi/fpdf_parser/fpdf_parser_utility.cpp
@@ -386,7 +386,7 @@ CFX_ByteTextBuf& operator<<(CFX_ByteTextBuf& buf, const CPDF_Object* pObj) {
       break;
     }
     case PDFOBJ_ARRAY: {
-      CPDF_Array* p = (CPDF_Array*)pObj;
+      const CPDF_Array* p = pObj->AsArray();
       buf << FX_BSTRC("[");
       for (FX_DWORD i = 0; i < p->GetCount(); i++) {
         CPDF_Object* pElement = p->GetElement(i);
diff --git a/core/src/fpdfapi/fpdf_render/fpdf_render.cpp b/core/src/fpdfapi/fpdf_render/fpdf_render.cpp
index cb5450f913..ccc8ce63cf 100644
--- a/core/src/fpdfapi/fpdf_render/fpdf_render.cpp
+++ b/core/src/fpdfapi/fpdf_render/fpdf_render.cpp
@@ -1224,9 +1224,8 @@ CPDF_TransferFunc* CPDF_DocRenderData::GetTransferFunc(CPDF_Object* pObj) {
   CPDF_Function* pFuncs[3] = {nullptr, nullptr, nullptr};
   FX_BOOL bUniTransfer = TRUE;
   FX_BOOL bIdentity = TRUE;
-  if (pObj->GetType() == PDFOBJ_ARRAY) {
+  if (CPDF_Array* pArray = pObj->AsArray()) {
     bUniTransfer = FALSE;
-    CPDF_Array* pArray = (CPDF_Array*)pObj;
     if (pArray->GetCount() < 3)
       return nullptr;
 
diff --git a/core/src/fpdfapi/fpdf_render/fpdf_render_image.cpp b/core/src/fpdfapi/fpdf_render/fpdf_render_image.cpp
index cdf2104f82..2754223f3e 100644
--- a/core/src/fpdfapi/fpdf_render/fpdf_render_image.cpp
+++ b/core/src/fpdfapi/fpdf_render/fpdf_render_image.cpp
@@ -412,8 +412,7 @@ FX_BOOL CPDF_ImageRenderer::StartRenderDIBSource() {
             bsDecodeType == FX_BSTRC("JPXDecode")) {
           m_Flags |= FXRENDER_IMAGE_LOSSY;
         }
-      } else if (pFilters->GetType() == PDFOBJ_ARRAY) {
-        CPDF_Array* pArray = (CPDF_Array*)pFilters;
+      } else if (CPDF_Array* pArray = pFilters->AsArray()) {
         for (FX_DWORD i = 0; i < pArray->GetCount(); i++) {
           CFX_ByteStringC bsDecodeType = pArray->GetConstString(i);
           if (bsDecodeType == FX_BSTRC("DCTDecode") ||
diff --git a/core/src/fpdfapi/fpdf_render/fpdf_render_loadimage.cpp b/core/src/fpdfapi/fpdf_render/fpdf_render_loadimage.cpp
index 79b4bba162..fecd6da9b2 100644
--- a/core/src/fpdfapi/fpdf_render/fpdf_render_loadimage.cpp
+++ b/core/src/fpdfapi/fpdf_render/fpdf_render_loadimage.cpp
@@ -482,8 +482,7 @@ FX_BOOL CPDF_DIBSource::LoadColorInfo(CPDF_Dictionary* pFormResources,
             m_bDoBpcCheck = FALSE;
             return TRUE;
           }
-        } else if (pFilter->GetType() == PDFOBJ_ARRAY) {
-          CPDF_Array* pArray = (CPDF_Array*)pFilter;
+        } else if (CPDF_Array* pArray = pFilter->AsArray()) {
           if (pArray->GetString(pArray->GetCount() - 1) ==
               FX_BSTRC("JPXDecode")) {
             m_bDoBpcCheck = FALSE;
@@ -570,8 +569,7 @@ DIB_COMP_DATA* CPDF_DIBSource::GetDecodeAndMaskArray(FX_BOOL& bDefaultDecode,
     if (pMask == NULL) {
       return pCompData;
     }
-    if (pMask->GetType() == PDFOBJ_ARRAY) {
-      CPDF_Array* pArray = (CPDF_Array*)pMask;
+    if (CPDF_Array* pArray = pMask->AsArray()) {
       if (pArray->GetCount() >= m_nComponents * 2) {
         for (FX_DWORD i = 0; i < m_nComponents; i++) {
           int min_num = pArray->GetInteger(i * 2);
@@ -953,8 +951,7 @@ void CPDF_DIBSource::ValidateDictParam() {
       } else if (filter == FX_BSTRC("DCTDecode")) {
         m_bpc = 8;
       }
-    } else if (pFilter->GetType() == PDFOBJ_ARRAY) {
-      CPDF_Array* pArray = (CPDF_Array*)pFilter;
+    } else if (CPDF_Array* pArray = pFilter->AsArray()) {
       if (pArray->GetString(pArray->GetCount() - 1) ==
               FX_BSTRC("CCITTFaxDecode") ||
           pArray->GetString(pArray->GetCount() - 1) ==