diff --git a/core/include/fpdfapi/fpdf_objects.h b/core/include/fpdfapi/fpdf_objects.h
index 622f39d..a41ff08 100644
--- a/core/include/fpdfapi/fpdf_objects.h
+++ b/core/include/fpdfapi/fpdf_objects.h
@@ -620,7 +620,7 @@
 
     CPDF_Dictionary*		GetDict() const
     {
-        return m_pStream->GetDict();
+        return m_pStream? m_pStream->GetDict() : NULL;
     }
 
     FX_LPCBYTE				GetData() const;
diff --git a/core/include/fpdfapi/fpdf_resource.h b/core/include/fpdfapi/fpdf_resource.h
index 49e7148..7e9e412 100644
--- a/core/include/fpdfapi/fpdf_resource.h
+++ b/core/include/fpdfapi/fpdf_resource.h
@@ -882,7 +882,7 @@
 
     CPDF_Dictionary*		GetDict() const
     {
-        return m_pStream->GetDict();
+        return m_pStream? m_pStream->GetDict(): NULL;
     }
 
     CPDF_Dictionary*		GetOC() const
diff --git a/core/src/fpdfapi/fpdf_edit/fpdf_edit_content.cpp b/core/src/fpdfapi/fpdf_edit/fpdf_edit_content.cpp
index 243c23f..e33a99b 100644
--- a/core/src/fpdfapi/fpdf_edit/fpdf_edit_content.cpp
+++ b/core/src/fpdfapi/fpdf_edit/fpdf_edit_content.cpp
@@ -48,7 +48,7 @@
         }
         ProcessImage(buf, (CPDF_ImageObject*)pPageObj);
     }
-    CPDF_Object* pContent = pPageDict->GetElementValue("Contents");
+    CPDF_Object* pContent = pPageDict ? pPageDict->GetElementValue("Contents") : NULL;
     if (pContent != NULL) {
         pPageDict->RemoveAt("Contents");
     }
@@ -94,7 +94,8 @@
         FX_DWORD dwSavedObjNum = pStream->GetObjNum();
         CFX_ByteString name = RealizeResource(pStream, "XObject");
         if (dwSavedObjNum == 0) {
-            pImageObj->m_pImage->Release();
+            if (pImageObj->m_pImage)
+                pImageObj->m_pImage->Release();
             pImageObj->m_pImage = m_pDocument->GetPageData()->GetImage(pStream);
         }
         buf << "/" << PDF_NameEncode(name) << " Do Q\n";
@@ -119,7 +120,8 @@
 }
 void CPDF_PageContentGenerate::TransformContent(CFX_Matrix& matrix)
 {
-    CPDF_Object* pContent = m_pPage->m_pFormDict->GetElementValue("Contents");
+    CPDF_Dictionary* pDict = m_pPage->m_pFormDict;
+    CPDF_Object* pContent = pDict ? pDict->GetElementValue("Contents") : NULL;
     if (!pContent) {
         return;
     }
diff --git a/core/src/fpdfapi/fpdf_edit/fpdf_edit_create.cpp b/core/src/fpdfapi/fpdf_edit/fpdf_edit_create.cpp
index bdbcccd..9eec7aa 100644
--- a/core/src/fpdfapi/fpdf_edit/fpdf_edit_create.cpp
+++ b/core/src/fpdfapi/fpdf_edit/fpdf_edit_create.cpp
@@ -334,7 +334,7 @@
 FX_BOOL CPDF_FlateEncoder::Initialize(CPDF_Stream* pStream, FX_BOOL bFlateEncode)
 {
     m_Acc.LoadAllData(pStream, TRUE);
-    if (pStream->GetDict()->KeyExist("Filter") || !bFlateEncode) {
+    if ((pStream && pStream->GetDict() && pStream->GetDict()->KeyExist("Filter")) || !bFlateEncode) {
         if (pStream->GetDict()->KeyExist("Filter") && !bFlateEncode) {
             CPDF_StreamAcc destAcc;
             destAcc.LoadAllData(pStream);
@@ -1482,7 +1482,8 @@
         if (m_bSecurityChanged && (m_dwFlags & FPDFCREATE_NO_ORIGINAL) == 0) {
             m_dwFlags &= ~FPDFCREATE_INCREMENTAL;
         }
-        m_pMetadata = m_pDocument->GetRoot()->GetElementValue(FX_BSTRC("Metadata"));
+        CPDF_Dictionary* pDict = m_pDocument->GetRoot();
+        m_pMetadata = pDict ? pDict->GetElementValue(FX_BSTRC("Metadata")) : NULL;
         if (m_dwFlags & FPDFCREATE_OBJECTSTREAM) {
             m_pXRefStream = FX_NEW CPDF_XRefStream;
             m_pXRefStream->Start();
@@ -2032,7 +2033,7 @@
     if (!m_pIDArray) {
         FX_LPDWORD pBuffer = NULL;
         m_pIDArray = CPDF_Array::Create();
-        CPDF_Object* pID1 = pOldIDArray->GetElement(0);
+        CPDF_Object* pID1 = pOldIDArray ? pOldIDArray->GetElement(0) : NULL;
         if (pID1) {
             m_pIDArray->Add(pID1->Clone());
         } else {
diff --git a/core/src/fpdfapi/fpdf_font/fpdf_font.cpp b/core/src/fpdfapi/fpdf_font/fpdf_font.cpp
index 72b8adb..b7ca5b1 100644
--- a/core/src/fpdfapi/fpdf_font/fpdf_font.cpp
+++ b/core/src/fpdfapi/fpdf_font/fpdf_font.cpp
@@ -78,7 +78,9 @@
         CFX_StockFontArray* pStockFonts = (CFX_StockFontArray*)value;
         for (int i = 0; i < 14; i ++) {
             if (pStockFonts->m_pStockFonts[i]) {
-                pStockFonts->m_pStockFonts[i]->GetFontDict()->Release();
+                CPDF_Dictionary* pFontDict = pStockFonts->m_pStockFonts[i]->GetFontDict();
+                if (pFontDict)
+                    pFontDict->Release();
                 delete pStockFonts->m_pStockFonts[i];
             }
         }
@@ -97,7 +99,9 @@
             CFX_StockFontArray* pStockFonts = (CFX_StockFontArray*)value;
             for (int i = 0; i < 14; i ++) {
                 if (pStockFonts->m_pStockFonts[i]) {
-                    pStockFonts->m_pStockFonts[i]->GetFontDict()->Release();
+                    CPDF_Dictionary* pFontDict = pStockFonts->m_pStockFonts[i]->GetFontDict();
+                    if (pFontDict)
+                        pFontDict->Release();
                     delete pStockFonts->m_pStockFonts[i];
                 }
             }
@@ -1698,7 +1702,7 @@
     if (name == NULL) {
         return NULL;
     }
-    CPDF_Stream* pStream = (CPDF_Stream*)m_pCharProcs->GetElementValue(name);
+    CPDF_Stream* pStream = (CPDF_Stream*)(m_pCharProcs ? m_pCharProcs->GetElementValue(name) : NULL);
     if (pStream == NULL || pStream->GetType() != PDFOBJ_STREAM) {
         return NULL;
     }
diff --git a/core/src/fpdfapi/fpdf_page/fpdf_page.cpp b/core/src/fpdfapi/fpdf_page/fpdf_page.cpp
index 3cfb93e..500fe4a 100644
--- a/core/src/fpdfapi/fpdf_page/fpdf_page.cpp
+++ b/core/src/fpdfapi/fpdf_page/fpdf_page.cpp
@@ -841,7 +841,8 @@
         m_pPageResources = m_pResources = NULL;
         return;
     }
-    m_pResources = GetPageAttr(FX_BSTRC("Resources"))->GetDict();
+    CPDF_Object* pageAttr = GetPageAttr(FX_BSTRC("Resources"));
+    m_pResources = pageAttr ? pageAttr->GetDict() : NULL;
     m_pPageResources = m_pResources;
     CPDF_Object* pRotate = GetPageAttr(FX_BSTRC("Rotate"));
     int rotate = 0;
@@ -946,7 +947,7 @@
 {
     m_pDocument = pDoc;
     m_pFormStream = pFormStream;
-    m_pFormDict = pFormStream->GetDict();
+    m_pFormDict = pFormStream ? pFormStream->GetDict() : NULL;
     m_pResources = m_pFormDict->GetDict(FX_BSTRC("Resources"));
     m_pPageResources = pPageResources;
     if (m_pResources == NULL) {
diff --git a/core/src/fpdfapi/fpdf_page/fpdf_page_colors.cpp b/core/src/fpdfapi/fpdf_page/fpdf_page_colors.cpp
index c13395c..ff44c59 100644
--- a/core/src/fpdfapi/fpdf_page/fpdf_page_colors.cpp
+++ b/core/src/fpdfapi/fpdf_page/fpdf_page_colors.cpp
@@ -281,7 +281,7 @@
     CPDF_Array* pParam = pDict->GetArray(FX_BSTRC("WhitePoint"));
     int i;
     for (i = 0; i < 3; i ++) {
-        m_WhitePoint[i] = pParam->GetNumber(i);
+        m_WhitePoint[i] = pParam ? pParam->GetNumber(i) : 0;
     }
     pParam = pDict->GetArray(FX_BSTRC("BlackPoint"));
     for (i = 0; i < 3; i ++) {
@@ -340,7 +340,7 @@
     CPDF_Array* pParam = pDict->GetArray(FX_BSTRC("WhitePoint"));
     int i;
     for (i = 0; i < 3; i ++) {
-        m_WhitePoint[i] = pParam->GetNumber(i);
+        m_WhitePoint[i] = pParam ? pParam->GetNumber(i) : 0;
     }
     pParam = pDict->GetArray(FX_BSTRC("BlackPoint"));
     for (i = 0; i < 3; i ++) {
@@ -438,7 +438,7 @@
     CPDF_Array* pParam = pDict->GetArray(FX_BSTRC("WhitePoint"));
     int i;
     for (i = 0; i < 3; i ++) {
-        m_WhitePoint[i] = pParam->GetNumber(i);
+        m_WhitePoint[i] = pParam ? pParam->GetNumber(i) : 0;
     }
     pParam = pDict->GetArray(FX_BSTRC("BlackPoint"));
     for (i = 0; i < 3; i ++) {
@@ -580,11 +580,12 @@
     if (pStream == NULL) {
         return FALSE;
     }
-    m_nComponents = pStream->GetDict()->GetInteger(FX_BSTRC("N"));
+    CPDF_Dictionary* pDict = pStream->GetDict();
+    m_nComponents = pDict ? pDict->GetInteger(FX_BSTRC("N")) : 0;
     if (m_nComponents < 0 || m_nComponents > (1 << 16)) {
         return FALSE;
     }
-    CPDF_Array* pRanges = pStream->GetDict()->GetArray(FX_BSTRC("Range"));
+    CPDF_Array* pRanges = pDict->GetArray(FX_BSTRC("Range"));
     m_pRanges = FX_Alloc(FX_FLOAT, m_nComponents * 2);
     for (int i = 0; i < m_nComponents * 2; i ++) {
         if (pRanges) {
@@ -600,7 +601,7 @@
         return FALSE;
     }
     if (m_pProfile->m_pTransform == NULL) {
-        CPDF_Object* pAlterCSObj = pStream->GetDict()->GetElementValue(FX_BSTRC("Alternate"));
+        CPDF_Object* pAlterCSObj = pDict ? pDict->GetElementValue(FX_BSTRC("Alternate")) : NULL;
         if (pAlterCSObj) {
             CPDF_ColorSpace* alter_cs = CPDF_ColorSpace::Load(pDoc, pAlterCSObj);
             if (alter_cs) {
@@ -1079,7 +1080,7 @@
         while (pos) {
             CFX_ByteString bsKey;
             CPDF_Object *pValue = pDict->GetNextElement(pos, bsKey);
-            if (pValue->GetType() == PDFOBJ_NAME) {
+            if (pValue && pValue->GetType() == PDFOBJ_NAME) {
                 pRet = _CSFromName(pValue->GetString());
             }
             if (pRet) {
diff --git a/core/src/fpdfapi/fpdf_page/fpdf_page_doc.cpp b/core/src/fpdfapi/fpdf_page/fpdf_page_doc.cpp
index a9d2c4d..c152b22 100644
--- a/core/src/fpdfapi/fpdf_page/fpdf_page_doc.cpp
+++ b/core/src/fpdfapi/fpdf_page/fpdf_page_doc.cpp
@@ -485,7 +485,7 @@
     if (bShading) {
         pPattern = FX_NEW CPDF_ShadingPattern(m_pPDFDoc, pPatternObj, bShading, matrix);
     } else {
-        CPDF_Dictionary* pDict = pPatternObj->GetDict();
+        CPDF_Dictionary* pDict = pPatternObj ? pPatternObj->GetDict() : NULL;
         if (pDict) {
             int type = pDict->GetInteger(FX_BSTRC("PatternType"));
             if (type == 1) {
diff --git a/core/src/fpdfapi/fpdf_page/fpdf_page_func.cpp b/core/src/fpdfapi/fpdf_page/fpdf_page_func.cpp
index 5b178f9..af22c56 100644
--- a/core/src/fpdfapi/fpdf_page/fpdf_page_func.cpp
+++ b/core/src/fpdfapi/fpdf_page/fpdf_page_func.cpp
@@ -486,7 +486,7 @@
     int i;
     FX_DWORD nTotalSamples = 1;
     for (i = 0; i < m_nInputs; i ++) {
-        m_pEncodeInfo[i].sizes = pSize->GetInteger(i);
+        m_pEncodeInfo[i].sizes = pSize ? pSize->GetInteger(i) : 0;
         if (!pSize && i == 0) {
             m_pEncodeInfo[i].sizes = pDict->GetInteger(FX_BSTRC("Size"));
         }
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 f53a5b2..628fb3d 100644
--- a/core/src/fpdfapi/fpdf_page/fpdf_page_graph_state.cpp
+++ b/core/src/fpdfapi/fpdf_page/fpdf_page_graph_state.cpp
@@ -194,7 +194,8 @@
     CPDF_ClipPathData* pData = GetModify();
     if (pData->m_TextCount + count > FPDF_CLIPPATH_MAX_TEXTS) {
         for (int i = 0; i < count; i ++) {
-            pTexts[i]->Release();
+            if (pTexts[i])
+                pTexts[i]->Release();
         }
         return;
     }
@@ -481,7 +482,8 @@
     FX_POSITION pos = pGS->GetStartPos();
     while (pos) {
         CFX_ByteString key_str;
-        CPDF_Object* pObject = pGS->GetNextElement(pos, key_str)->GetDirect();
+        CPDF_Object* pElement = pGS->GetNextElement(pos, key_str);
+        CPDF_Object* pObject = pElement ? pElement->GetDirect() : NULL;
         if (pObject == NULL) {
             continue;
         }
@@ -625,7 +627,7 @@
 }
 CPDF_ContentMarkItem::~CPDF_ContentMarkItem()
 {
-    if (m_ParamType == DirectDict) {
+    if (m_ParamType == DirectDict && m_pParam) {
         ((CPDF_Dictionary*)m_pParam)->Release();
     }
 }
diff --git a/core/src/fpdfapi/fpdf_page/fpdf_page_parser.cpp b/core/src/fpdfapi/fpdf_page/fpdf_page_parser.cpp
index ff67096..5e8c1b5 100644
--- a/core/src/fpdfapi/fpdf_page/fpdf_page_parser.cpp
+++ b/core/src/fpdfapi/fpdf_page/fpdf_page_parser.cpp
@@ -140,7 +140,8 @@
             m_ParamStartPos = 0;
         }
         if (m_ParamBuf1[m_ParamStartPos].m_Type == 0) {
-            m_ParamBuf1[m_ParamStartPos].m_pObject->Release();
+            if (CPDF_Object* pObject = m_ParamBuf1[m_ParamStartPos].m_pObject)
+                pObject->Release();
         }
         return m_ParamStartPos;
     }
@@ -187,7 +188,8 @@
     FX_DWORD index = m_ParamStartPos;
     for (FX_DWORD i = 0; i < m_ParamCount; i ++) {
         if (m_ParamBuf1[index].m_Type == 0) {
-            m_ParamBuf1[index].m_pObject->Release();
+            if (CPDF_Object* pObject = m_ParamBuf1[index].m_pObject)
+                pObject->Release();
         }
         index ++;
         if (index == PARAM_BUF_SIZE) {
@@ -238,7 +240,7 @@
     if (param.m_Type == PDFOBJ_NAME) {
         return CFX_ByteString(param.m_Name.m_Buffer, param.m_Name.m_Len);
     }
-    if (param.m_Type == 0) {
+    if (param.m_Type == 0 && param.m_pObject) {
         return param.m_pObject->GetString();
     }
     return CFX_ByteString();
@@ -256,7 +258,7 @@
     if (param.m_Type == PDFOBJ_NUMBER) {
         return param.m_Number.m_bInteger ? (FX_FLOAT)param.m_Number.m_Integer : param.m_Number.m_Float;
     }
-    if (param.m_Type == 0) {
+    if (param.m_Type == 0 && param.m_pObject) {
         return param.m_pObject->GetNumber();
     }
     return 0;
@@ -653,7 +655,7 @@
     if (m_Options.m_bTextOnly) {
         return;
     }
-    CPDF_Array* pArray = GetObject(1)->GetArray();
+    CPDF_Array* pArray = GetObject(1) ? GetObject(1)->GetArray() : NULL;
     if (pArray == NULL) {
         return;
     }
@@ -728,7 +730,7 @@
         m_bResourceMissing = TRUE;
         return;
     }
-    CFX_ByteStringC type = pXObject->GetDict()->GetConstString(FX_BSTRC("Subtype"));
+    CFX_ByteStringC type = pXObject->GetDict() ? pXObject->GetDict()->GetConstString(FX_BSTRC("Subtype")) : CFX_ByteStringC();
     if (type == FX_BSTRC("Image")) {
         if (m_Options.m_bTextOnly) {
             return;
@@ -1425,7 +1427,7 @@
 }
 void CPDF_StreamContentParser::Handle_ShowText_Positioning()
 {
-    CPDF_Array* pArray = GetObject(0)->GetArray();
+    CPDF_Array* pArray = GetObject(0) ? GetObject(0)->GetArray() : NULL;
     if (pArray == NULL) {
         return;
     }
@@ -1457,10 +1459,11 @@
             pStrs[iSegment] = str;
             pKerning[iSegment ++] = 0;
         } else {
+            FX_FLOAT num = pObj ? pObj->GetNumber() : 0;
             if (iSegment == 0) {
-                fInitKerning += pObj->GetNumber();
+                fInitKerning += num;
             } else {
-                pKerning[iSegment - 1] += pObj->GetNumber();
+                pKerning[iSegment - 1] += num;
             }
         }
     }
diff --git a/core/src/fpdfapi/fpdf_page/fpdf_page_parser_new.cpp b/core/src/fpdfapi/fpdf_page/fpdf_page_parser_new.cpp
index 5442f9b..24ec743 100644
--- a/core/src/fpdfapi/fpdf_page/fpdf_page_parser_new.cpp
+++ b/core/src/fpdfapi/fpdf_page/fpdf_page_parser_new.cpp
@@ -498,9 +498,9 @@
         m_bSameLastDict = TRUE;
     }
     m_ImageSrcBuf.Clear();
-    if (m_pLastCloneImageDict) {
+    if (m_pLastCloneImageDict)
         m_pLastCloneImageDict->Release();
-    }
+
     m_pLastCloneImageDict = (CPDF_Dictionary*)m_pLastImageDict->Clone();
     if (m_pLastCloneImageDict->KeyExist(FX_BSTRC("Filter"))) {
         m_WordState = 10;
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 8cd9f2b..fe5e59c 100644
--- a/core/src/fpdfapi/fpdf_page/fpdf_page_parser_old.cpp
+++ b/core/src/fpdfapi/fpdf_page/fpdf_page_parser_old.cpp
@@ -91,7 +91,7 @@
         CPDF_Object* pObj = m_pSyntax->ReadNextObject();
         if (!key.IsEmpty()) {
             pDict->SetAt(key, pObj, m_pDocument);
-        } else {
+        } else if (pObj) {
             pObj->Release();
         }
     }
@@ -1064,7 +1064,7 @@
             } else {
                 CPDF_Array* pContent = m_pObjects->m_pFormDict->GetArray(FX_BSTRC("Contents"));
                 m_pStreamArray[m_CurrentOffset] = FX_NEW CPDF_StreamAcc;
-                CPDF_Stream* pStreamObj = (CPDF_Stream*)pContent->GetElementValue(m_CurrentOffset);
+                CPDF_Stream* pStreamObj = (CPDF_Stream*)(pContent ? pContent->GetElementValue(m_CurrentOffset) : NULL);
                 m_pStreamArray[m_CurrentOffset]->LoadAllData(pStreamObj, FALSE);
                 m_CurrentOffset ++;
             }
diff --git a/core/src/fpdfapi/fpdf_page/fpdf_page_pattern.cpp b/core/src/fpdfapi/fpdf_page/fpdf_page_pattern.cpp
index 6c6c095..8cb6dc7 100644
--- a/core/src/fpdfapi/fpdf_page/fpdf_page_pattern.cpp
+++ b/core/src/fpdfapi/fpdf_page/fpdf_page_pattern.cpp
@@ -97,7 +97,7 @@
     if (m_ShadingType != 0) {
         return TRUE;
     }
-    CPDF_Dictionary* pShadingDict = m_pShadingObj->GetDict();
+    CPDF_Dictionary* pShadingDict = m_pShadingObj ? m_pShadingObj->GetDict() : NULL;
     if (pShadingDict == NULL) {
         return FALSE;
     }
diff --git a/core/src/fpdfapi/fpdf_parser/fpdf_parser_decode.cpp b/core/src/fpdfapi/fpdf_parser/fpdf_parser_decode.cpp
index 6b2483e..5854d71 100644
--- a/core/src/fpdfapi/fpdf_parser/fpdf_parser_decode.cpp
+++ b/core/src/fpdfapi/fpdf_parser/fpdf_parser_decode.cpp
@@ -45,7 +45,7 @@
         return (FX_DWORD) - 1;
     }
     int state = 0;
-	FX_UINT32 res = 0;
+    FX_UINT32 res = 0;
     pos = dest_size = 0;
     while (pos < src_size) {
         FX_BYTE ch = src_buf[pos++];
@@ -281,11 +281,11 @@
                        CPDF_Dictionary*& pImageParms, FX_DWORD last_estimated_size, FX_BOOL bImageAcc)
 
 {
-    CPDF_Object* pDecoder = pDict->GetElementValue(FX_BSTRC("Filter"));
+    CPDF_Object* pDecoder = pDict ? pDict->GetElementValue(FX_BSTRC("Filter")) : NULL;
     if (pDecoder == NULL || (pDecoder->GetType() != PDFOBJ_ARRAY && pDecoder->GetType() != PDFOBJ_NAME)) {
         return FALSE;
     }
-    CPDF_Object* pParams = pDict->GetElementValue(FX_BSTRC("DecodeParms"));
+    CPDF_Object* pParams = pDict ? pDict->GetElementValue(FX_BSTRC("DecodeParms")) : NULL;
     CFX_ByteStringArray DecoderList;
     CFX_PtrArray ParamList;
     if (pDecoder->GetType() == PDFOBJ_ARRAY) {
@@ -304,7 +304,7 @@
         }
     } else {
         DecoderList.Add(pDecoder->GetConstString());
-        ParamList.Add(pParams->GetDict());
+        ParamList.Add(pParams ? pParams->GetDict() : NULL);
     }
     FX_LPBYTE last_buf = (FX_LPBYTE)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 a498204..cd100a8 100644
--- a/core/src/fpdfapi/fpdf_parser/fpdf_parser_document.cpp
+++ b/core/src/fpdfapi/fpdf_parser/fpdf_parser_document.cpp
@@ -61,11 +61,13 @@
 {
     m_bLinearized = TRUE;
     m_LastObjNum = m_pParser->GetLastObjNum();
-    m_pRootDict = GetIndirectObject(m_pParser->GetRootObjNum())->GetDict();
+    CPDF_Object* indirectObj = GetIndirectObject(m_pParser->GetRootObjNum());
+    m_pRootDict = indirectObj ? indirectObj->GetDict() : NULL;
     if (m_pRootDict == NULL) {
         return;
     }
-    m_pInfoDict = GetIndirectObject(m_pParser->GetInfoObjNum())->GetDict();
+    indirectObj = GetIndirectObject(m_pParser->GetInfoObjNum());
+    m_pInfoDict = indirectObj ? indirectObj->GetDict() : NULL;
     CPDF_Array* pIDArray = m_pParser->GetIDArray();
     if (pIDArray) {
         m_ID1 = pIDArray->GetString(0);
@@ -336,7 +338,7 @@
         if (pPageDict == pThisPageDict) {
             continue;
         }
-        CPDF_Object* pContents = pPageDict->GetElement(FX_BSTRC("Contents"));
+        CPDF_Object* pContents = pPageDict ? pPageDict->GetElement(FX_BSTRC("Contents")) : NULL;
         if (pContents == NULL) {
             continue;
         }
diff --git a/core/src/fpdfapi/fpdf_parser/fpdf_parser_encrypt.cpp b/core/src/fpdfapi/fpdf_parser/fpdf_parser_encrypt.cpp
index fadcd38..e09bbbb 100644
--- a/core/src/fpdfapi/fpdf_parser/fpdf_parser_encrypt.cpp
+++ b/core/src/fpdfapi/fpdf_parser/fpdf_parser_encrypt.cpp
@@ -292,11 +292,11 @@
 FX_BOOL CPDF_StandardSecurityHandler::AES256_CheckPassword(FX_LPCBYTE password, FX_DWORD size,
         FX_BOOL bOwner, FX_LPBYTE key)
 {
-    CFX_ByteString okey = m_pEncryptDict->GetString(FX_BSTRC("O"));
+    CFX_ByteString okey = m_pEncryptDict ? m_pEncryptDict->GetString(FX_BSTRC("O")) : CFX_ByteString();
     if (okey.GetLength() < 48) {
         return FALSE;
     }
-    CFX_ByteString ukey = m_pEncryptDict->GetString(FX_BSTRC("U"));
+    CFX_ByteString ukey = m_pEncryptDict ? m_pEncryptDict->GetString(FX_BSTRC("U")) : CFX_ByteString();
     if (ukey.GetLength() < 48) {
         return FALSE;
     }
@@ -331,7 +331,7 @@
         }
         CRYPT_SHA256Finish(sha, digest);
     }
-    CFX_ByteString ekey = m_pEncryptDict->GetString(bOwner ? FX_BSTRC("OE") : FX_BSTRC("UE"));
+    CFX_ByteString ekey = m_pEncryptDict ? m_pEncryptDict->GetString(bOwner ? FX_BSTRC("OE") : FX_BSTRC("UE")) : CFX_ByteString();
     if (ekey.GetLength() < 32) {
         return FALSE;
     }
@@ -391,7 +391,7 @@
 {
     CalcEncryptKey(m_pEncryptDict, password, pass_size, key, key_len, bIgnoreEncryptMeta,
                    m_pParser->GetIDArray());
-    CFX_ByteString ukey = m_pEncryptDict->GetString(FX_BSTRC("U"));
+    CFX_ByteString ukey = m_pEncryptDict ? m_pEncryptDict->GetString(FX_BSTRC("U")) : CFX_ByteString();
     if (ukey.GetLength() < 16) {
         return FALSE;
     }
diff --git a/core/src/fpdfapi/fpdf_parser/fpdf_parser_fdf.cpp b/core/src/fpdfapi/fpdf_parser/fpdf_parser_fdf.cpp
index 36cc9db..dd4eedd 100644
--- a/core/src/fpdfapi/fpdf_parser/fpdf_parser_fdf.cpp
+++ b/core/src/fpdfapi/fpdf_parser/fpdf_parser_fdf.cpp
@@ -111,7 +111,8 @@
 }
 CFX_WideString CFDF_Document::GetWin32Path() const
 {
-    CPDF_Object* pFileSpec = m_pRootDict->GetDict(FX_BSTRC("FDF"))->GetElementValue(FX_BSTRC("F"));
+    CPDF_Dictionary* pDict = m_pRootDict ? m_pRootDict->GetDict(FX_BSTRC("FDF")) : NULL;
+    CPDF_Object* pFileSpec = pDict ? pDict->GetElementValue(FX_BSTRC("F")) : NULL;
     if (pFileSpec == NULL) {
         return CFX_WideString();
     }
@@ -203,7 +204,10 @@
         if (wsFileName.IsEmpty() && pDict->KeyExist(FX_BSTRC("DOS"))) {
             wsFileName = CFX_WideString::FromLocal(pDict->GetString(FX_BSTRC("DOS")));
         }
-    } else {
+    }
+    else if (!pFileSpec)
+        wsFileName = CFX_WideString();
+    else {
         wsFileName = CFX_WideString::FromLocal(pFileSpec->GetString());
     }
     if (wsFileName[0] != '/') {
diff --git a/core/src/fpdfapi/fpdf_parser/fpdf_parser_filters.cpp b/core/src/fpdfapi/fpdf_parser/fpdf_parser_filters.cpp
index 1e4e157..610fb39 100644
--- a/core/src/fpdfapi/fpdf_parser/fpdf_parser_filters.cpp
+++ b/core/src/fpdfapi/fpdf_parser/fpdf_parser_filters.cpp
@@ -76,11 +76,11 @@
         case FXBSTR_ID('L', 'Z', 'W', 0): {
                 CFX_DataFilter* pFilter;
                 if (id == FXBSTR_ID('L', 'Z', 'W', 'D') || id == FXBSTR_ID('L', 'Z', 'W', 0)) {
-                    pFilter = FX_NEW CPDF_LzwFilter(pParam->GetInteger("EarlyChange", 1));
+                    pFilter = FX_NEW CPDF_LzwFilter(pParam ? pParam->GetInteger("EarlyChange", 1) : 1);
                 } else {
                     pFilter = FX_NEW CPDF_FlateFilter;
                 }
-                if (pParam->GetInteger("Predictor", 1) > 1) {
+                if ((pParam ? pParam->GetInteger("Predictor", 1) : 1) > 1) {
                     CFX_DataFilter* pPredictor = FX_NEW CPDF_PredictorFilter(pParam->GetInteger(FX_BSTRC("Predictor"), 1),
                                                  pParam->GetInteger(FX_BSTRC("Colors"), 1), pParam->GetInteger(FX_BSTRC("BitsPerComponent"), 8),
                                                  pParam->GetInteger(FX_BSTRC("Columns"), 1));
diff --git a/core/src/fpdfapi/fpdf_parser/fpdf_parser_objects.cpp b/core/src/fpdfapi/fpdf_parser/fpdf_parser_objects.cpp
index bd8b157..6c93bcb 100644
--- a/core/src/fpdfapi/fpdf_parser/fpdf_parser_objects.cpp
+++ b/core/src/fpdfapi/fpdf_parser/fpdf_parser_objects.cpp
@@ -7,9 +7,6 @@
 #include "../../../include/fpdfapi/fpdf_parser.h"
 void CPDF_Object::Release()
 {
-    if (this == NULL) {
-        return;
-    }
     if (m_ObjNum) {
         return;
     }
@@ -39,9 +36,6 @@
 }
 CFX_ByteString CPDF_Object::GetString() const
 {
-    if (this == NULL) {
-        return CFX_ByteString();
-    }
     switch (m_Type) {
         case PDFOBJ_BOOLEAN:
             return ((CPDF_Boolean*)this)->m_bValue ? "true" : "false";
@@ -67,9 +61,6 @@
 }
 CFX_ByteStringC CPDF_Object::GetConstString() const
 {
-    if (this == NULL) {
-        return CFX_ByteStringC();
-    }
     switch (m_Type) {
         case PDFOBJ_STRING:
             return CFX_ByteStringC((FX_LPCBYTE)((CPDF_String*)this)->m_String, ((CPDF_String*)this)->m_String.GetLength());
@@ -91,9 +82,6 @@
 }
 FX_FLOAT CPDF_Object::GetNumber() const
 {
-    if (this == NULL) {
-        return 0;
-    }
     switch (m_Type) {
         case PDFOBJ_NUMBER:
             return ((CPDF_Number*)this)->GetNumber();
@@ -117,9 +105,6 @@
 }
 int CPDF_Object::GetInteger() const
 {
-    if (this == NULL) {
-        return 0;
-    }
     switch (m_Type) {
         case PDFOBJ_BOOLEAN:
             return ((CPDF_Boolean*)this)->m_bValue;
@@ -143,9 +128,6 @@
 }
 CPDF_Dictionary* CPDF_Object::GetDict() const
 {
-    if (this == NULL) {
-        return NULL;
-    }
     switch (m_Type) {
         case PDFOBJ_DICTIONARY:
             return (CPDF_Dictionary*)this;
@@ -167,13 +149,10 @@
 }
 CPDF_Array* CPDF_Object::GetArray() const
 {
-    if (this == NULL) {
-        return NULL;
-    }
-    if (m_Type == PDFOBJ_ARRAY) {
+    if (m_Type == PDFOBJ_ARRAY) 
         return (CPDF_Array*)this;
-    }
-    return NULL;
+    else
+        return NULL;
 }
 void CPDF_Object::SetString(const CFX_ByteString& str)
 {
@@ -207,11 +186,11 @@
     if (this == pOther) {
         return TRUE;
     }
-    if (this == NULL || pOther == NULL) {
+    if (pOther == NULL) {
         return FALSE;
     }
     if (pOther->m_Type != m_Type) {
-        if (m_Type == PDFOBJ_REFERENCE) {
+        if (m_Type == PDFOBJ_REFERENCE && GetDirect()) {
             return GetDirect()->IsIdentical(pOther);
         } else if (pOther->m_Type == PDFOBJ_REFERENCE) {
             return IsIdentical(pOther->GetDirect());
@@ -242,9 +221,6 @@
 }
 CPDF_Object* CPDF_Object::GetDirect() const
 {
-    if (this == NULL) {
-        return NULL;
-    }
     if (m_Type != PDFOBJ_REFERENCE) {
         return (CPDF_Object*)this;
     }
@@ -261,9 +237,6 @@
 }
 CPDF_Object* CPDF_Object::CloneInternal(FX_BOOL bDirect, CFX_MapPtrToPtr* visited) const
 {
-    if (this == NULL) {
-        return NULL;
-    }
     switch (m_Type) {
         case PDFOBJ_BOOLEAN:
             return FX_NEW CPDF_Boolean(((CPDF_Boolean*)this)->m_bValue);
@@ -303,7 +276,11 @@
                 CPDF_StreamAcc acc;
                 acc.LoadAllData(pThis, TRUE);
                 FX_DWORD streamSize = acc.GetSize();
-                CPDF_Stream* pObj = FX_NEW CPDF_Stream(acc.DetachData(), streamSize, (CPDF_Dictionary*)((CPDF_Object*)pThis->GetDict())->CloneInternal(bDirect, visited));
+                CPDF_Stream* pObj;
+                if (pThis->GetDict())
+                    pObj = FX_NEW CPDF_Stream(acc.DetachData(), streamSize, (CPDF_Dictionary*)((CPDF_Object*)pThis->GetDict())->CloneInternal(bDirect, visited));
+                else
+                    pObj = FX_NEW CPDF_Stream(acc.DetachData(), streamSize, NULL);
                 return pObj;
             }
         case PDFOBJ_REFERENCE: {
@@ -311,7 +288,11 @@
                 FX_DWORD obj_num = pRef->m_RefObjNum;
                 if (bDirect && !visited->GetValueAt((void*)(FX_UINTPTR)obj_num)) {
                     visited->SetAt((void*)(FX_UINTPTR)obj_num, (void*)1);
-                    CPDF_Object* ret = pRef->GetDirect()->CloneInternal(TRUE, visited);
+                    CPDF_Object* ret;
+                    if (pRef->GetDirect())
+                        ret = pRef->GetDirect()->CloneInternal(TRUE, visited);
+                    else
+                        ret = NULL;
                     return ret;
                 } else {
                     return FX_NEW CPDF_Reference(pRef->m_pObjList, obj_num);
@@ -322,9 +303,6 @@
 }
 CPDF_Object* CPDF_Object::CloneRef(CPDF_IndirectObjects* pDoc) const
 {
-    if (this == NULL) {
-        return NULL;
-    }
     if (m_ObjNum) {
         return FX_NEW CPDF_Reference(pDoc, m_ObjNum);
     }
@@ -332,9 +310,6 @@
 }
 CFX_WideString CPDF_Object::GetUnicodeText(CFX_CharMap* pCharMap) const
 {
-    if (this == NULL) {
-        return CFX_WideString();
-    }
     if (m_Type == PDFOBJ_STRING) {
         return PDF_DecodeText(((CPDF_String*)this)->m_String, pCharMap);
     } else if (m_Type == PDFOBJ_STREAM) {
@@ -349,9 +324,6 @@
 }
 void CPDF_Object::SetUnicodeText(FX_LPCWSTR pUnicodes, int len)
 {
-    if (this == NULL) {
-        return;
-    }
     if (m_Type == PDFOBJ_STRING) {
         ((CPDF_String*)this)->m_String = PDF_EncodeText(pUnicodes, len);
     } else if (m_Type == PDFOBJ_STREAM) {
@@ -411,13 +383,14 @@
     int size = m_Objects.GetSize();
     CPDF_Object** pList = (CPDF_Object**)m_Objects.GetData();
     for (int i = 0; i < size; i ++) {
-        pList[i]->Release();
+        if (pList[i])
+            pList[i]->Release();
     }
 }
 CFX_FloatRect CPDF_Array::GetRect()
 {
     CFX_FloatRect rect;
-    if (this == NULL || m_Type != PDFOBJ_ARRAY || m_Objects.GetSize() != 4) {
+    if (m_Type != PDFOBJ_ARRAY || m_Objects.GetSize() != 4) {
         return rect;
     }
     rect.left = GetNumber(0);
@@ -429,7 +402,7 @@
 CFX_AffineMatrix CPDF_Array::GetMatrix()
 {
     CFX_AffineMatrix matrix;
-    if (this == NULL || m_Type != PDFOBJ_ARRAY || m_Objects.GetSize() != 6) {
+    if (m_Type != PDFOBJ_ARRAY || m_Objects.GetSize() != 6) {
         return matrix;
     }
     matrix.Set(GetNumber(0), GetNumber(1), GetNumber(2), GetNumber(3), GetNumber(4), GetNumber(5));
@@ -437,9 +410,6 @@
 }
 CPDF_Object* CPDF_Array::GetElement(FX_DWORD i) const
 {
-    if (this == NULL) {
-        return NULL;
-    }
     if (i >= (FX_DWORD)m_Objects.GetSize()) {
         return NULL;
     }
@@ -447,9 +417,6 @@
 }
 CPDF_Object* CPDF_Array::GetElementValue(FX_DWORD i) const
 {
-    if (this == NULL) {
-        return NULL;
-    }
     if (i >= (FX_DWORD)m_Objects.GetSize()) {
         return NULL;
     }
@@ -457,23 +424,25 @@
 }
 CFX_ByteString CPDF_Array::GetString(FX_DWORD i) const
 {
-    if (this && i < (FX_DWORD)m_Objects.GetSize()) {
+    if (i < (FX_DWORD)m_Objects.GetSize()) {
         CPDF_Object* p = (CPDF_Object*)m_Objects.GetAt(i);
         return p->GetString();
     }
-    return CFX_ByteString();
+    else
+        return CFX_ByteString();
 }
 CFX_ByteStringC CPDF_Array::GetConstString(FX_DWORD i) const
 {
-    if (this && i < (FX_DWORD)m_Objects.GetSize()) {
+    if (i < (FX_DWORD)m_Objects.GetSize()) {
         CPDF_Object* p = (CPDF_Object*)m_Objects.GetAt(i);
         return p->GetConstString();
     }
-    return CFX_ByteStringC();
+    else
+        return CFX_ByteStringC();
 }
 int CPDF_Array::GetInteger(FX_DWORD i) const
 {
-    if (this == NULL || i >= (FX_DWORD)m_Objects.GetSize()) {
+    if (i >= (FX_DWORD)m_Objects.GetSize()) {
         return 0;
     }
     CPDF_Object* p = (CPDF_Object*)m_Objects.GetAt(i);
@@ -481,7 +450,7 @@
 }
 FX_FLOAT CPDF_Array::GetNumber(FX_DWORD i) const
 {
-    if (this == NULL || i >= (FX_DWORD)m_Objects.GetSize()) {
+    if (i >= (FX_DWORD)m_Objects.GetSize()) {
         return 0;
     }
     CPDF_Object* p = (CPDF_Object*)m_Objects.GetAt(i);
@@ -517,23 +486,25 @@
 }
 void CPDF_Array::RemoveAt(FX_DWORD i)
 {
-    ASSERT(this != NULL && m_Type == PDFOBJ_ARRAY);
+    ASSERT(m_Type == PDFOBJ_ARRAY);
     if (i >= (FX_DWORD)m_Objects.GetSize()) {
         return;
     }
     CPDF_Object* p = (CPDF_Object*)m_Objects.GetAt(i);
-    p->Release();
+    if (p)
+        p->Release();
     m_Objects.RemoveAt(i);
 }
 void CPDF_Array::SetAt(FX_DWORD i, CPDF_Object* pObj, CPDF_IndirectObjects* pObjs)
 {
-    ASSERT(this != NULL && m_Type == PDFOBJ_ARRAY);
+    ASSERT(m_Type == PDFOBJ_ARRAY);
     ASSERT(i < (FX_DWORD)m_Objects.GetSize());
     if (i >= (FX_DWORD)m_Objects.GetSize()) {
         return;
     }
     CPDF_Object* pOld = (CPDF_Object*)m_Objects.GetAt(i);
-    pOld->Release();
+    if (pOld)
+        pOld->Release();
     if (pObj->GetObjNum()) {
         ASSERT(pObjs != NULL);
         pObj = CPDF_Reference::Create(pObjs, pObj->GetObjNum());
@@ -560,29 +531,29 @@
 }
 void CPDF_Array::AddName(const CFX_ByteString& str)
 {
-    ASSERT(this != NULL && m_Type == PDFOBJ_ARRAY);
+    ASSERT(m_Type == PDFOBJ_ARRAY);
     Add(FX_NEW CPDF_Name(str));
 }
 void CPDF_Array::AddString(const CFX_ByteString& str)
 {
-    ASSERT(this != NULL && m_Type == PDFOBJ_ARRAY);
+    ASSERT(m_Type == PDFOBJ_ARRAY);
     Add(FX_NEW CPDF_String(str));
 }
 void CPDF_Array::AddInteger(int i)
 {
-    ASSERT(this != NULL && m_Type == PDFOBJ_ARRAY);
+    ASSERT(m_Type == PDFOBJ_ARRAY);
     Add(FX_NEW CPDF_Number(i));
 }
 void CPDF_Array::AddNumber(FX_FLOAT f)
 {
-    ASSERT(this != NULL && m_Type == PDFOBJ_ARRAY);
+    ASSERT(m_Type == PDFOBJ_ARRAY);
     CPDF_Number* pNumber = FX_NEW CPDF_Number;
     pNumber->SetNumber(f);
     Add(pNumber);
 }
 void CPDF_Array::AddReference(CPDF_IndirectObjects* pDoc, FX_DWORD objnum)
 {
-    ASSERT(this != NULL && m_Type == PDFOBJ_ARRAY);
+    ASSERT(m_Type == PDFOBJ_ARRAY);
     Add(FX_NEW CPDF_Reference(pDoc, objnum));
 }
 FX_BOOL CPDF_Array::Identical(CPDF_Array* pOther) const
@@ -601,7 +572,8 @@
     FX_POSITION pos = m_Map.GetStartPosition();
     while (pos) {
         FX_LPVOID value = m_Map.GetNextValue(pos);
-        ((CPDF_Object*)value)->Release();
+        if (value)
+            ((CPDF_Object*)value)->Release();
     }
 }
 FX_POSITION CPDF_Dictionary::GetStartPos() const
@@ -619,123 +591,99 @@
 }
 CPDF_Object* CPDF_Dictionary::GetElement(FX_BSTR key) const
 {
-    if (this == NULL) {
-        return NULL;
-    }
     CPDF_Object* p = NULL;
     m_Map.Lookup(key, (void*&)p);
     return p;
 }
 CPDF_Object* CPDF_Dictionary::GetElementValue(FX_BSTR key) const
 {
-    if (this == NULL) {
-        return NULL;
-    }
     CPDF_Object* p = NULL;
     m_Map.Lookup(key, (void*&)p);
-    return p->GetDirect();
+    return p ? p->GetDirect() : NULL;
 }
 CFX_ByteString CPDF_Dictionary::GetString(FX_BSTR key) const
 {
-    if (this) {
-        CPDF_Object* p = NULL;
-        m_Map.Lookup(key, (void*&)p);
-        if (p) {
-            return p->GetString();
-        }
-    }
-    return CFX_ByteString();
+    CPDF_Object* p = NULL;
+    m_Map.Lookup(key, (void*&)p);
+    if (p)
+        return p->GetString();
+    else
+        return CFX_ByteString();
 }
 CFX_ByteStringC CPDF_Dictionary::GetConstString(FX_BSTR key) const
 {
-    if (this) {
-        CPDF_Object* p = NULL;
-        m_Map.Lookup(key, (void*&)p);
-        if (p) {
-            return p->GetConstString();
-        }
-    }
-    return CFX_ByteStringC();
+    CPDF_Object* p = NULL;
+    m_Map.Lookup(key, (void*&)p);
+    if (p)
+        return p->GetConstString();
+    else
+        return CFX_ByteStringC();
 }
 CFX_WideString CPDF_Dictionary::GetUnicodeText(FX_BSTR key, CFX_CharMap* pCharMap) const
 {
-    if (this) {
-        CPDF_Object* p = NULL;
-        m_Map.Lookup(key, (void*&)p);
-        if (p) {
-            if(p->GetType() == PDFOBJ_REFERENCE) {
-                p = ((CPDF_Reference*)p)->GetDirect();
-                return p->GetUnicodeText(pCharMap);
-            } else {
-                return p->GetUnicodeText(pCharMap);
-            }
+    CPDF_Object* p = NULL;
+    m_Map.Lookup(key, (void*&)p);
+    if (p) {
+        if(p->GetType() == PDFOBJ_REFERENCE) {
+            p = ((CPDF_Reference*)p)->GetDirect();
+            return p->GetUnicodeText(pCharMap);
+        } else {
+            return p->GetUnicodeText(pCharMap);
         }
     }
     return CFX_WideString();
 }
 CFX_ByteString CPDF_Dictionary::GetString(FX_BSTR key, FX_BSTR def) const
 {
-    if (this) {
-        CPDF_Object* p = NULL;
-        m_Map.Lookup(key, (void*&)p);
-        if (p) {
-            return p->GetString();
-        }
+    CPDF_Object* p = NULL;
+    m_Map.Lookup(key, (void*&)p);
+    if (p) {
+        return p->GetString();
     }
     return CFX_ByteString(def);
 }
 CFX_ByteStringC CPDF_Dictionary::GetConstString(FX_BSTR key, FX_BSTR def) const
 {
-    if (this) {
-        CPDF_Object* p = NULL;
-        m_Map.Lookup(key, (void*&)p);
-        if (p) {
-            return p->GetConstString();
-        }
-    }
-    return CFX_ByteStringC(def);
+    CPDF_Object* p = NULL;
+    m_Map.Lookup(key, (void*&)p);
+    if (p)
+        return p->GetConstString();
+    else
+        return CFX_ByteStringC(def);
 }
 int CPDF_Dictionary::GetInteger(FX_BSTR key) const
 {
-    if (this) {
-        CPDF_Object* p = NULL;
-        m_Map.Lookup(key, (void*&)p);
-        if (p) {
-            return p->GetInteger();
-        }
+    CPDF_Object* p = NULL;
+    m_Map.Lookup(key, (void*&)p);
+    if (p) {
+        return p->GetInteger();
     }
     return 0;
 }
 int CPDF_Dictionary::GetInteger(FX_BSTR key, int def) const
 {
-    if (this) {
-        CPDF_Object* p = NULL;
-        m_Map.Lookup(key, (void*&)p);
-        if (p) {
-            return p->GetInteger();
-        }
+    CPDF_Object* p = NULL;
+    m_Map.Lookup(key, (void*&)p);
+    if (p) {
+        return p->GetInteger();
     }
     return def;
 }
 FX_FLOAT CPDF_Dictionary::GetNumber(FX_BSTR key) const
 {
-    if (this) {
-        CPDF_Object* p = NULL;
-        m_Map.Lookup(key, (void*&)p);
-        if (p) {
-            return p->GetNumber();
-        }
+    CPDF_Object* p = NULL;
+    m_Map.Lookup(key, (void*&)p);
+    if (p) {
+        return p->GetNumber();
     }
     return 0;
 }
 FX_BOOL CPDF_Dictionary::GetBoolean(FX_BSTR key, FX_BOOL bDefault) const
 {
-    if (this) {
-        CPDF_Object* p = NULL;
-        m_Map.Lookup(key, (void*&)p);
-        if (p && p->GetType() == PDFOBJ_BOOLEAN) {
-            return p->GetInteger();
-        }
+    CPDF_Object* p = NULL;
+    m_Map.Lookup(key, (void*&)p);
+    if (p && p->GetType() == PDFOBJ_BOOLEAN) {
+        return p->GetInteger();
     }
     return bDefault;
 }
@@ -787,23 +735,19 @@
 }
 FX_BOOL CPDF_Dictionary::KeyExist(FX_BSTR key) const
 {
-    if (this == NULL) {
-        return FALSE;
-    }
     FX_LPVOID value;
     return m_Map.Lookup(key, value);
 }
 void CPDF_Dictionary::SetAt(FX_BSTR key, CPDF_Object* pObj, CPDF_IndirectObjects* pObjs)
 {
-    ASSERT(this != NULL && m_Type == PDFOBJ_DICTIONARY);
+    ASSERT(m_Type == PDFOBJ_DICTIONARY);
     CPDF_Object* p = NULL;
     m_Map.Lookup(key, (void*&)p);
     if (p == pObj) {
         return;
     }
-    if (p) {
+    if (p)
         p->Release();
-    }
     if (pObj) {
         if (pObj->GetObjNum()) {
             ASSERT(pObjs != NULL);
@@ -816,12 +760,12 @@
 }
 void CPDF_Dictionary::AddValue(FX_BSTR key, CPDF_Object* pObj)
 {
-    ASSERT(this != NULL && m_Type == PDFOBJ_DICTIONARY);
+    ASSERT(m_Type == PDFOBJ_DICTIONARY);
     m_Map.AddValue(key, pObj);
 }
 void CPDF_Dictionary::RemoveAt(FX_BSTR key)
 {
-    ASSERT(this != NULL && m_Type == PDFOBJ_DICTIONARY);
+    ASSERT(m_Type == PDFOBJ_DICTIONARY);
     CPDF_Object* p = NULL;
     m_Map.Lookup(key, (void*&)p);
     if (p == NULL) {
@@ -832,7 +776,7 @@
 }
 void CPDF_Dictionary::ReplaceKey(FX_BSTR oldkey, FX_BSTR newkey)
 {
-    ASSERT(this != NULL && m_Type == PDFOBJ_DICTIONARY);
+    ASSERT(m_Type == PDFOBJ_DICTIONARY);
     CPDF_Object* p = NULL;
     m_Map.Lookup(oldkey, (void*&)p);
     if (p == NULL) {
@@ -843,12 +787,6 @@
 }
 FX_BOOL CPDF_Dictionary::Identical(CPDF_Dictionary* pOther) const
 {
-    if (this == NULL) {
-        if (pOther == NULL) {
-            return TRUE;
-        }
-        return FALSE;
-    }
     if (pOther == NULL) {
         return FALSE;
     }
@@ -860,6 +798,8 @@
         CFX_ByteString key;
         FX_LPVOID value;
         m_Map.GetNextAssoc(pos, key, value);
+        if (!value)
+            return FALSE;
         if (!((CPDF_Object*)value)->IsIdentical(pOther->GetElement(key))) {
             return FALSE;
         }
@@ -1014,6 +954,9 @@
 }
 FX_BOOL CPDF_Stream::Identical(CPDF_Stream* pOther) const
 {
+    if (!m_pDict)
+        return pOther->m_pDict ? FALSE : TRUE;
+
     if (!m_pDict->Identical(pOther->m_pDict)) {
         return FALSE;
     }
diff --git a/core/src/fpdfapi/fpdf_parser/fpdf_parser_parser.cpp b/core/src/fpdfapi/fpdf_parser/fpdf_parser_parser.cpp
index c705ea7..5e926c3 100644
--- a/core/src/fpdfapi/fpdf_parser/fpdf_parser_parser.cpp
+++ b/core/src/fpdfapi/fpdf_parser/fpdf_parser_parser.cpp
@@ -78,7 +78,7 @@
     }
     ReleaseEncryptHandler();
     SetEncryptDictionary(NULL);
-    if (m_bOwnFileRead && m_Syntax.m_pFileAccess != NULL) {
+    if (m_bOwnFileRead && m_Syntax.m_pFileAccess) {
         m_Syntax.m_pFileAccess->Release();
         m_Syntax.m_pFileAccess = NULL;
     }
@@ -96,7 +96,8 @@
     m_ObjVersion.RemoveAll();
     FX_INT32 iLen = m_Trailers.GetSize();
     for (FX_INT32 i = 0; i < iLen; ++i) {
-        m_Trailers.GetAt(i)->Release();
+        if (CPDF_Dictionary* trailer = m_Trailers.GetAt(i))
+            trailer->Release();
     }
     m_Trailers.RemoveAll();
     if (m_pLinearized) {
@@ -1110,7 +1111,7 @@
 }
 CPDF_Array* CPDF_Parser::GetIDArray()
 {
-    CPDF_Object* pID = m_pTrailer->GetElement(FX_BSTRC("ID"));
+    CPDF_Object* pID = m_pTrailer ? m_pTrailer->GetElement(FX_BSTRC("ID")) : NULL;
     if (pID == NULL) {
         return NULL;
     }
@@ -1125,7 +1126,7 @@
 }
 FX_DWORD CPDF_Parser::GetRootObjNum()
 {
-    CPDF_Reference* pRef = (CPDF_Reference*)m_pTrailer->GetElement(FX_BSTRC("Root"));
+    CPDF_Reference* pRef = m_pTrailer ? (CPDF_Reference*)m_pTrailer->GetElement(FX_BSTRC("Root")) : NULL;
     if (pRef == NULL || pRef->GetType() != PDFOBJ_REFERENCE) {
         return 0;
     }
@@ -1133,7 +1134,7 @@
 }
 FX_DWORD CPDF_Parser::GetInfoObjNum()
 {
-    CPDF_Reference* pRef = (CPDF_Reference*)m_pTrailer->GetElement(FX_BSTRC("Info"));
+    CPDF_Reference* pRef = m_pTrailer ? (CPDF_Reference*)m_pTrailer->GetElement(FX_BSTRC("Info")) : NULL;
     if (pRef == NULL || pRef->GetType() != PDFOBJ_REFERENCE) {
         return 0;
     }
@@ -1491,7 +1492,7 @@
     if (!m_pLinearized) {
         return FALSE;
     }
-    if (m_pLinearized->GetDict()->GetElement(FX_BSTRC("Linearized"))) {
+    if (m_pLinearized->GetDict() && m_pLinearized->GetDict()->GetElement(FX_BSTRC("Linearized"))) {
         m_Syntax.GetNextWord(bIsNumber);
         CPDF_Object *pLen = m_pLinearized->GetDict()->GetElement(FX_BSTRC("L"));
         if (!pLen) {
@@ -2150,7 +2151,8 @@
             FX_BOOL bIsNumber;
             CFX_ByteString key = GetNextWord(bIsNumber);
             if (key.IsEmpty()) {
-                pDict->Release();
+                if (pDict)
+                    pDict->Release();
                 return NULL;
             }
             FX_FILESIZE SavedPos = m_Pos - key.GetLength();
@@ -2206,7 +2208,8 @@
             if (pStream) {
                 return pStream;
             }
-            pDict->Release();
+            if (pDict)
+                pDict->Release();
             return NULL;
         } else {
             m_Pos = SavedPos;
@@ -2307,7 +2310,8 @@
                 if (m_WordBuffer[0] == ']') {
                     return pArray;
                 }
-                pArray->Release();
+                if (pArray)
+                    pArray->Release();
                 return NULL;
             }
             pArray->Add(pObj);
@@ -2332,7 +2336,8 @@
             FX_FILESIZE SavedPos = m_Pos;
             CFX_ByteString key = GetNextWord(bIsNumber);
             if (key.IsEmpty()) {
-                pDict->Release();
+                if (pDict)
+                    pDict->Release();
                 return NULL;
             }
             if (key == FX_BSTRC(">>")) {
@@ -2348,7 +2353,8 @@
             key = PDF_NameDecode(key);
             CPDF_Object* pObj = GetObject(pObjList, objnum, gennum, level + 1);
             if (pObj == NULL) {
-                pDict->Release();
+                if (pDict)
+                    pDict->Release();
                 FX_BYTE ch;
                 while (1) {
                     if (!GetNextChar(ch)) {
@@ -2380,7 +2386,8 @@
             if (pStream) {
                 return pStream;
             }
-            pDict->Release();
+            if (pDict)
+                pDict->Release();
             return NULL;
         } else {
             m_Pos = SavedPos;
@@ -2835,7 +2842,7 @@
                 pObj = pObj->GetDict();
             case PDFOBJ_DICTIONARY: {
                     CPDF_Dictionary *pDict = pObj->GetDict();
-                    if (pDict->GetString("Type") == "Page" && !bParsePage) {
+                    if (pDict && pDict->GetString("Type") == "Page" && !bParsePage) {
                         continue;
                     }
                     FX_POSITION pos = pDict->GetStartPos();
@@ -3157,7 +3164,7 @@
 FX_BOOL CPDF_DataAvail::PreparePageItem()
 {
     CPDF_Dictionary *pRoot = m_pDocument->GetRoot();
-    CPDF_Reference* pRef = (CPDF_Reference*)pRoot->GetElement(FX_BSTRC("Pages"));
+    CPDF_Reference* pRef = pRoot ? (CPDF_Reference*)pRoot->GetElement(FX_BSTRC("Pages")) : NULL;
     if (pRef == NULL || pRef->GetType() != PDFOBJ_REFERENCE) {
         m_docStatus = PDF_DATAAVAIL_ERROR;
         return FALSE;
@@ -3270,7 +3277,8 @@
         m_docStatus = PDF_DATAAVAIL_ERROR;
         return FALSE;
     }
-    CPDF_Object *pKids = pPages->GetDict()->GetElement(FX_BSTRC("Kids"));
+    CPDF_Dictionary* pDict = pPages->GetDict();
+    CPDF_Object *pKids = pDict ? pDict->GetElement(FX_BSTRC("Kids")) : NULL;
     if (!pKids) {
         return TRUE;
     }
@@ -3344,17 +3352,18 @@
 FX_BOOL CPDF_DataAvail::CheckFirstPage(IFX_DownloadHints *pHints)
 {
     FX_DWORD dwFirstPageEndOffset = 0;
-    CPDF_Object *pEndOffSet = m_pLinearized->GetDict()->GetElement(FX_BSTRC("E"));
+    CPDF_Dictionary* pDict = m_pLinearized->GetDict();
+    CPDF_Object *pEndOffSet = pDict ? pDict->GetElement(FX_BSTRC("E")) : NULL;
     if (!pEndOffSet) {
         m_docStatus = PDF_DATAAVAIL_ERROR;
         return FALSE;
     }
-    CPDF_Object *pXRefOffset  = m_pLinearized->GetDict()->GetElement(FX_BSTRC("T"));
+    CPDF_Object *pXRefOffset = pDict ? pDict->GetElement(FX_BSTRC("T")) : NULL;
     if (!pXRefOffset) {
         m_docStatus = PDF_DATAAVAIL_ERROR;
         return FALSE;
     }
-    CPDF_Object *pFileLen = m_pLinearized->GetDict()->GetElement(FX_BSTRC("L"));
+    CPDF_Object *pFileLen = pDict ? pDict->GetElement(FX_BSTRC("L")) : NULL;
     if (!pFileLen) {
         m_docStatus = PDF_DATAAVAIL_ERROR;
         return FALSE;
@@ -3473,7 +3482,7 @@
     if (!m_pLinearized) {
         return FALSE;
     }
-    if (m_pLinearized->GetDict()->GetElement(FX_BSTRC("Linearized"))) {
+    if (m_pLinearized->GetDict() && m_pLinearized->GetDict()->GetElement(FX_BSTRC("Linearized"))) {
         CPDF_Object *pLen = m_pLinearized->GetDict()->GetElement(FX_BSTRC("L"));
         if (!pLen) {
             return FALSE;
@@ -3548,7 +3557,8 @@
             m_Pos += m_parser.m_Syntax.SavePos();
             return 0;
         }
-        CPDF_Object *pName = pObj->GetDict()->GetElement(FX_BSTRC("Type"));
+        CPDF_Dictionary* pDict = pObj->GetDict();
+        CPDF_Object *pName = pDict ? pDict->GetElement(FX_BSTRC("Type")) : NULL;
         if (pName && pName->GetType() == PDFOBJ_NAME) {
             if (pName->GetString() == FX_BSTRC("XRef")) {
                 m_Pos += m_parser.m_Syntax.SavePos();
@@ -3908,10 +3918,11 @@
         return FALSE;
     }
     pPageNode->m_dwPageNo = dwPageNo;
-    CFX_ByteString type = pPage->GetDict()->GetString(FX_BSTRC("Type"));
+    CPDF_Dictionary* pDict = pPage->GetDict();
+    CFX_ByteString type = pDict ? pDict->GetString(FX_BSTRC("Type")) : CFX_ByteString();
     if (type == FX_BSTRC("Pages")) {
         pPageNode->m_type = PDF_PAGENODE_PAGES;
-        CPDF_Object *pKids = pPage->GetDict()->GetElement(FX_BSTRC("Kids"));
+        CPDF_Object *pKids = pDict->GetElement(FX_BSTRC("Kids"));
         if (!pKids) {
             m_docStatus = PDF_DATAAVAIL_PAGE;
             return TRUE;
diff --git a/core/src/fpdfapi/fpdf_render/fpdf_render_image.cpp b/core/src/fpdfapi/fpdf_render/fpdf_render_image.cpp
index 39241e1..1452b9d 100644
--- a/core/src/fpdfapi/fpdf_render/fpdf_render_image.cpp
+++ b/core/src/fpdfapi/fpdf_render/fpdf_render_image.cpp
@@ -1082,7 +1082,11 @@
         CPDF_Array* pBC = pSMaskDict->GetArray(FX_BSTRC("BC"));
         FX_ARGB back_color = 0xff000000;
         if (pBC) {
-            pCSObj = pGroup->GetDict()->GetDict(FX_BSTRC("Group"))->GetElementValue(FX_BSTRC("CS"));
+            CPDF_Dictionary* pDict = pGroup->GetDict();
+            if (pDict && pDict->GetDict(FX_BSTRC("Group")))
+                pCSObj = pDict->GetDict(FX_BSTRC("Group"))->GetElementValue(FX_BSTRC("CS"));
+            else
+                pCSObj = NULL;
             pCS = m_pContext->m_pDocument->LoadColorSpace(pCSObj);
             if (pCS) {
                 FX_FLOAT R, G, B;
diff --git a/core/src/fpdfapi/fpdf_render/fpdf_render_loadimage.cpp b/core/src/fpdfapi/fpdf_render/fpdf_render_loadimage.cpp
index 91a3725..6befe11 100644
--- a/core/src/fpdfapi/fpdf_render/fpdf_render_loadimage.cpp
+++ b/core/src/fpdfapi/fpdf_render/fpdf_render_loadimage.cpp
@@ -914,7 +914,7 @@
 FX_DWORD CPDF_DIBSource::GetValidBpp() const
 {
     FX_DWORD bpc = m_bpc;
-    CPDF_Object * pFilter = m_pDict->GetElementValue(FX_BSTRC("Filter"));
+	CPDF_Object * pFilter = m_pDict ? m_pDict->GetElementValue(FX_BSTRC("Filter")) : NULL;
     if (pFilter) {
         if (pFilter->GetType() == PDFOBJ_NAME) {
             CFX_ByteString filter = pFilter->GetString();
diff --git a/core/src/fpdfdoc/doc_annot.cpp b/core/src/fpdfdoc/doc_annot.cpp
index 227578a..8952845 100644
--- a/core/src/fpdfdoc/doc_annot.cpp
+++ b/core/src/fpdfdoc/doc_annot.cpp
@@ -165,7 +165,7 @@
 }
 CFX_ByteString CPDF_Annot::GetSubType() const
 {
-    return m_pAnnotDict->GetConstString(FX_BSTRC("Subtype"));
+    return m_pAnnotDict ? m_pAnnotDict->GetConstString(FX_BSTRC("Subtype")) : CFX_ByteStringC();
 }
 void CPDF_Annot::GetRect(CPDF_Rect& rect) const
 {
@@ -202,7 +202,8 @@
         if (as.IsEmpty()) {
             CFX_ByteString value = pAnnotDict->GetString(FX_BSTRC("V"));
             if (value.IsEmpty()) {
-                value = pAnnotDict->GetDict(FX_BSTRC("Parent"))->GetString(FX_BSTRC("V"));
+                CPDF_Dictionary* pDict = pAnnotDict->GetDict(FX_BSTRC("Parent"));
+                value = pDict ? pDict->GetString(FX_BSTRC("V")) : CFX_ByteString();
             }
             if (value.IsEmpty() || !((CPDF_Dictionary*)psub)->KeyExist(value)) {
                 as = FX_BSTRC("Off");
diff --git a/core/src/fpdfdoc/doc_ap.cpp b/core/src/fpdfdoc/doc_ap.cpp
index 784d89d..6a8ab37 100644
--- a/core/src/fpdfdoc/doc_ap.cpp
+++ b/core/src/fpdfdoc/doc_ap.cpp
@@ -10,11 +10,11 @@
 #include "../../include/fpdfdoc/fpdf_ap.h"
 FX_BOOL FPDF_GenerateAP(CPDF_Document* pDoc, CPDF_Dictionary* pAnnotDict)
 {
-    if (pAnnotDict->GetConstString("Subtype") != FX_BSTRC("Widget")) {
+    if (!pAnnotDict || pAnnotDict->GetConstString("Subtype") != FX_BSTRC("Widget")) {
         return FALSE;
     }
     CFX_ByteString field_type = FPDF_GetFieldAttr(pAnnotDict, "FT")->GetString();
-    FX_DWORD flags = FPDF_GetFieldAttr(pAnnotDict, "Ff")->GetInteger();
+    FX_DWORD flags = FPDF_GetFieldAttr(pAnnotDict, "Ff")? FPDF_GetFieldAttr(pAnnotDict, "Ff")->GetInteger() : 0;
     if (field_type == "Tx") {
         return CPVT_GenerateAP::GenerateTextFieldAP(pDoc, pAnnotDict);
     } else if (field_type == "Ch") {
@@ -253,7 +253,7 @@
     if (!pFormDict) {
         return FALSE;
     }
-    CFX_ByteString DA = FPDF_GetFieldAttr(pAnnotDict, "DA")->GetString();
+    CFX_ByteString DA = FPDF_GetFieldAttr(pAnnotDict, "DA") ? FPDF_GetFieldAttr(pAnnotDict, "DA")->GetString() : CFX_ByteString();
     if (DA.IsEmpty()) {
         DA = pFormDict->GetString("DA");
     }
@@ -277,7 +277,7 @@
         bUseFormRes = TRUE;
     }
     CPDF_Dictionary * pDRFontDict = NULL;
-    if ((pDRFontDict = pDRDict->GetDict("Font"))) {
+    if (pDRDict && (pDRFontDict = pDRDict->GetDict("Font"))) {
         pFontDict = pDRFontDict->GetDict(sFontName.Mid(1));
         if (!pFontDict && !bUseFormRes) {
             pDRDict = pFormDict->GetDict(FX_BSTRC("DR"));
@@ -430,11 +430,11 @@
     }
     switch (nWidgetType) {
         case 0: {
-                CFX_WideString swValue = FPDF_GetFieldAttr(pAnnotDict, "V")->GetUnicodeText();
-                FX_INT32 nAlign = FPDF_GetFieldAttr(pAnnotDict, "Q")->GetInteger();
-                FX_DWORD dwFlags = FPDF_GetFieldAttr(pAnnotDict, "Ff")->GetInteger();
-                FX_DWORD dwMaxLen = FPDF_GetFieldAttr(pAnnotDict, "MaxLen")->GetInteger();
-                CPVT_FontMap map(pDoc, pStreamDict->GetDict("Resources"), pDefFont, sFontName.Right(sFontName.GetLength() - 1));
+                CFX_WideString swValue = FPDF_GetFieldAttr(pAnnotDict, "V")? FPDF_GetFieldAttr(pAnnotDict, "V")->GetUnicodeText() : CFX_WideString();
+                FX_INT32 nAlign = FPDF_GetFieldAttr(pAnnotDict, "Q")? FPDF_GetFieldAttr(pAnnotDict, "Q")->GetInteger() : 0;
+                FX_DWORD dwFlags = FPDF_GetFieldAttr(pAnnotDict, "Ff")? FPDF_GetFieldAttr(pAnnotDict, "Ff")->GetInteger() : 0;
+                FX_DWORD dwMaxLen = FPDF_GetFieldAttr(pAnnotDict, "MaxLen") ? FPDF_GetFieldAttr(pAnnotDict, "MaxLen")->GetInteger() : 0;
+                CPVT_FontMap map(pDoc, pStreamDict ? pStreamDict->GetDict("Resources") : NULL , pDefFont, sFontName.Right(sFontName.GetLength() - 1));
                 CPVT_Provider prd(&map);
                 CPDF_VariableText vt;
                 vt.SetProvider(&prd);
@@ -482,8 +482,8 @@
             }
             break;
         case 1: {
-                CFX_WideString swValue = FPDF_GetFieldAttr(pAnnotDict, "V")->GetUnicodeText();
-                CPVT_FontMap map(pDoc, pStreamDict->GetDict("Resources"), pDefFont, sFontName.Right(sFontName.GetLength() - 1));
+                CFX_WideString swValue = FPDF_GetFieldAttr(pAnnotDict, "V") ? FPDF_GetFieldAttr(pAnnotDict, "V")->GetUnicodeText() : CFX_WideString();
+                CPVT_FontMap map(pDoc, pStreamDict ? pStreamDict->GetDict("Resources"):NULL, pDefFont, sFontName.Right(sFontName.GetLength() - 1));
                 CPVT_Provider prd(&map);
                 CPDF_VariableText vt;
                 vt.SetProvider(&prd);
@@ -534,11 +534,11 @@
             }
             break;
         case 2: {
-                CPVT_FontMap map(pDoc, pStreamDict->GetDict("Resources"), pDefFont, sFontName.Right(sFontName.GetLength() - 1));
+                CPVT_FontMap map(pDoc, pStreamDict ? pStreamDict->GetDict("Resources"):NULL, pDefFont, sFontName.Right(sFontName.GetLength() - 1));
                 CPVT_Provider prd(&map);
-                CPDF_Array * pOpts = FPDF_GetFieldAttr(pAnnotDict, "Opt")->GetArray();
-                CPDF_Array * pSels = FPDF_GetFieldAttr(pAnnotDict, "I")->GetArray();
-                FX_INT32 nTop = FPDF_GetFieldAttr(pAnnotDict, "TI")->GetInteger();
+                CPDF_Array * pOpts = FPDF_GetFieldAttr(pAnnotDict, "Opt") ? FPDF_GetFieldAttr(pAnnotDict, "Opt")->GetArray() : NULL;
+                CPDF_Array * pSels = FPDF_GetFieldAttr(pAnnotDict, "I") ? FPDF_GetFieldAttr(pAnnotDict, "I")->GetArray() : NULL;
+                FX_INT32 nTop = FPDF_GetFieldAttr(pAnnotDict, "TI") ? FPDF_GetFieldAttr(pAnnotDict, "TI")->GetInteger() : 0;
                 CFX_ByteTextBuf sBody;
                 if (pOpts) {
                     FX_FLOAT fy = rcBody.top;
diff --git a/core/src/fpdfdoc/doc_basic.cpp b/core/src/fpdfdoc/doc_basic.cpp
index 199a9a6..25f641c 100644
--- a/core/src/fpdfdoc/doc_basic.cpp
+++ b/core/src/fpdfdoc/doc_basic.cpp
@@ -72,7 +72,10 @@
 }
 CPDF_NameTree::CPDF_NameTree(CPDF_Document* pDoc, FX_BSTR category)
 {
-    m_pRoot = pDoc->GetRoot()->GetDict(FX_BSTRC("Names"))->GetDict(category);
+    if (pDoc->GetRoot() && pDoc->GetRoot()->GetDict(FX_BSTRC("Names")))
+        m_pRoot = pDoc->GetRoot()->GetDict(FX_BSTRC("Names"))->GetDict(category);
+    else
+        m_pRoot = NULL;
 }
 static CPDF_Object* SearchNameNode(CPDF_Dictionary* pNode, const CFX_ByteString& csName,
                                    int& nIndex, CPDF_Array** ppFind, int nLevel = 0)
diff --git a/core/src/fpdfdoc/doc_formfield.cpp b/core/src/fpdfdoc/doc_formfield.cpp
index 5484486..e51acf9 100644
--- a/core/src/fpdfdoc/doc_formfield.cpp
+++ b/core/src/fpdfdoc/doc_formfield.cpp
@@ -32,8 +32,8 @@
 }
 void CPDF_FormField::SyncFieldFlags()
 {
-    CFX_ByteString type_name = FPDF_GetFieldAttr(m_pDict, "FT")->GetString();
-    FX_DWORD flags = FPDF_GetFieldAttr(m_pDict, "Ff")->GetInteger();
+    CFX_ByteString type_name = FPDF_GetFieldAttr(m_pDict, "FT") ? FPDF_GetFieldAttr(m_pDict, "FT")->GetString() : CFX_ByteString();
+    FX_DWORD flags = FPDF_GetFieldAttr(m_pDict, "Ff")? FPDF_GetFieldAttr(m_pDict, "Ff")->GetInteger() : 0;
     m_Flags = 0;
     if (flags & 1) {
         m_Flags |= FORMFIELD_READONLY;
@@ -485,7 +485,8 @@
         if (index < 0) {
             return -1;
         }
-        sel_value = ((CPDF_Array*)pValue)->GetElementValue(index)->GetUnicodeText();
+        CPDF_Object* elementValue = ((CPDF_Array*)pValue)->GetElementValue(index);
+        sel_value = elementValue ? elementValue->GetUnicodeText() : CFX_WideString();
     }
     if (index < CountSelectedOptions()) {
         int iOptIndex = GetSelectedOptionIndex(index);
@@ -1076,9 +1077,9 @@
 }
 void CPDF_FormField::LoadDA()
 {
-    CFX_ByteString DA = FPDF_GetFieldAttr(m_pDict, "DA")->GetString();
+    CFX_ByteString DA = FPDF_GetFieldAttr(m_pDict, "DA") ? FPDF_GetFieldAttr(m_pDict, "DA")->GetString() : CFX_ByteString();
     if (DA.IsEmpty()) {
-        DA = m_pForm->m_pFormDict->GetString("DA");
+        DA = m_pForm->m_pFormDict ? m_pForm->m_pFormDict->GetString("DA") : CFX_ByteString();
     }
     if (DA.IsEmpty()) {
         return;
@@ -1086,7 +1087,11 @@
     CPDF_SimpleParser syntax(DA);
     syntax.FindTagParam("Tf", 2);
     CFX_ByteString font_name = syntax.GetWord();
-    CPDF_Dictionary* pFontDict = m_pForm->m_pFormDict->GetDict("DR")->GetDict("Font")->GetDict(font_name);
+    CPDF_Dictionary* pFontDict = NULL;
+    if (m_pForm->m_pFormDict && m_pForm->m_pFormDict->GetDict("DR") &&
+        m_pForm->m_pFormDict->GetDict("DR")->GetDict("Font") )
+    pFontDict = m_pForm->m_pFormDict->GetDict("DR")->GetDict("Font")->GetDict(font_name);
+
     if (pFontDict == NULL) {
         return;
     }
diff --git a/core/src/fpdftext/fpdf_text_int.cpp b/core/src/fpdftext/fpdf_text_int.cpp
index 6baf6ad..8736575 100644
--- a/core/src/fpdftext/fpdf_text_int.cpp
+++ b/core/src/fpdftext/fpdf_text_int.cpp
@@ -1442,7 +1442,7 @@
         CPDF_ContentMarkItem& item = pMarkData->GetItem(n);
         CFX_ByteString tagStr = (CFX_ByteString)item.GetName();
         pDict = (CPDF_Dictionary*)item.GetParam();
-        CPDF_String* temp = (CPDF_String*)pDict->GetElement(FX_BSTRC("ActualText"));
+        CPDF_String* temp = (CPDF_String*)(pDict ? pDict->GetElement(FX_BSTRC("ActualText")) : NULL);
         if (temp) {
             bExist = TRUE;
             actText = temp->GetUnicodeText();
diff --git a/core/src/fxcrt/fx_xml_parser.cpp b/core/src/fxcrt/fx_xml_parser.cpp
index c3d4b9c..b7e58a0 100644
--- a/core/src/fxcrt/fx_xml_parser.cpp
+++ b/core/src/fxcrt/fx_xml_parser.cpp
@@ -8,7 +8,7 @@
 #include "xml_int.h"
 CXML_Parser::~CXML_Parser()
 {
-    if (m_bOwnedStream) {
+    if (m_bOwnedStream && m_pDataAcc) {
         m_pDataAcc->Release();
     }
 }
diff --git a/fpdfsdk/src/formfiller/FFL_CBA_Fontmap.cpp b/fpdfsdk/src/formfiller/FFL_CBA_Fontmap.cpp
index 0c7cd48..8e10cc2 100644
--- a/fpdfsdk/src/formfiller/FFL_CBA_Fontmap.cpp
+++ b/fpdfsdk/src/formfiller/FFL_CBA_Fontmap.cpp
@@ -239,14 +239,16 @@
 	}
 	
 	CFX_ByteString sDA;
-	
-	sDA = FPDF_GetFieldAttr(m_pAnnotDict, "DA")->GetString();
+	CPDF_Object* pObj;
+	if ((pObj = FPDF_GetFieldAttr(m_pAnnotDict, "DA")))
+		sDA = pObj->GetString();
 
 	if (bWidget)
 	{
 		if (sDA.IsEmpty())
 		{
-			sDA = FPDF_GetFieldAttr(pAcroFormDict, "DA")->GetString();	
+			pObj = FPDF_GetFieldAttr(pAcroFormDict, "DA");
+			sDA = pObj ? pObj->GetString() : CFX_ByteString();
 		}
 	}
 	
diff --git a/fpdfsdk/src/fpdf_ext.cpp b/fpdfsdk/src/fpdf_ext.cpp
index 916cb20..93f6e18 100644
--- a/fpdfsdk/src/fpdf_ext.cpp
+++ b/fpdfsdk/src/fpdf_ext.cpp
@@ -172,15 +172,15 @@
 		if(pRootDict->KeyExist("Names"))
 		{
 			CPDF_Dictionary* pNameDict = pRootDict->GetDict("Names");
-			if(pNameDict->KeyExist("EmbeddedFiles"))
+			if (pNameDict && pNameDict->KeyExist("EmbeddedFiles"))
 			{
 				FPDF_UnSupportError(FPDF_UNSP_DOC_ATTACHMENT);
 				return;
 			}
-			else if(pNameDict->KeyExist("JavaScript"))
+			else if (pNameDict && pNameDict->KeyExist("JavaScript"))
 			{
 				CPDF_Dictionary* pJSDict = pNameDict->GetDict("JavaScript");
-				CPDF_Array * pArray = pJSDict->GetArray("Names");
+				CPDF_Array * pArray = pJSDict ? pJSDict->GetArray("Names") : NULL;
 				if (pArray) {
 					int nCount = pArray->GetCount();
 					for(int i=0; i<nCount; i++)
diff --git a/fpdfsdk/src/fpdf_transformpage.cpp b/fpdfsdk/src/fpdf_transformpage.cpp
index 729b1cd..a666666 100644
--- a/fpdfsdk/src/fpdf_transformpage.cpp
+++ b/fpdfsdk/src/fpdf_transformpage.cpp
@@ -96,9 +96,9 @@
 
 	CPDF_Page* pPage = (CPDF_Page*)page;
 	CPDF_Dictionary* pPageDic = pPage->m_pFormDict;
-	CPDF_Object* pContentObj = pPageDic->GetElement("Contents");
+	CPDF_Object* pContentObj = pPageDic ? pPageDic->GetElement("Contents") : NULL;
 	if(!pContentObj)
-		pContentObj = pPageDic->GetArray("Contents");
+		pContentObj = pPageDic ? pPageDic->GetArray("Contents") : NULL;
 	if(!pContentObj)
 		return FALSE;
 	
@@ -260,9 +260,9 @@
 		return;
 	CPDF_Page* pPage = (CPDF_Page*)page;
 	CPDF_Dictionary* pPageDic = pPage->m_pFormDict;
-	CPDF_Object* pContentObj = pPageDic->GetElement("Contents");
+	CPDF_Object* pContentObj = pPageDic ? pPageDic->GetElement("Contents") : NULL;
 	if(!pContentObj)
-		pContentObj = pPageDic->GetArray("Contents");
+		pContentObj = pPageDic ? pPageDic->GetArray("Contents") : NULL;
 	if(!pContentObj)
 		return;
 
diff --git a/fpdfsdk/src/fpdfeditpage.cpp b/fpdfsdk/src/fpdfeditpage.cpp
index 4c9fd35..2e84aa5 100644
--- a/fpdfsdk/src/fpdfeditpage.cpp
+++ b/fpdfsdk/src/fpdfeditpage.cpp
@@ -102,7 +102,7 @@
 DLLEXPORT int STDCALL FPDFPage_GetRotation(FPDF_PAGE page)
 {
 	CPDF_Page* pPage = (CPDF_Page*)page;
-	if (!pPage || !pPage->m_pFormDict || !pPage->m_pFormDict->KeyExist("Type")
+	if (!pPage || !pPage->m_pFormDict || !pPage->m_pFormDict->KeyExist("Type") || !pPage->m_pFormDict->GetElement("Type")->GetDirect()
 		|| pPage->m_pFormDict->GetElement("Type")->GetDirect()->GetString().Compare("Page"))
 	{
 		return -1;
@@ -112,8 +112,8 @@
 	int rotate = 0;
 	if(pDict != NULL)
 	{
-		if(pDict->KeyExist("Rotate"))
-			rotate = pDict->GetElement("Rotate")->GetDirect()->GetInteger() / 90;
+		if (pDict->KeyExist("Rotate"))
+			rotate = pDict->GetElement("Rotate")->GetDirect()? pDict->GetElement("Rotate")->GetDirect()->GetInteger() / 90 : 0;
 		else
 		{
 			if(pDict->KeyExist("Parent"))
@@ -123,7 +123,7 @@
 				{
 					if(pPages->KeyExist("Rotate"))
 					{
-						rotate = pPages->GetElement("Rotate")->GetDirect()->GetInteger() / 90;
+						rotate = pPages->GetElement("Rotate")->GetDirect()? pPages->GetElement("Rotate")->GetDirect()->GetInteger() / 90 : 0;
 						break;
 					}
 					else if(pPages->KeyExist("Parent"))
@@ -144,7 +144,7 @@
 DLLEXPORT void STDCALL FPDFPage_InsertObject(FPDF_PAGE page, FPDF_PAGEOBJECT page_obj)
 {
 	CPDF_Page* pPage = (CPDF_Page*)page;
-	if (!pPage || !pPage->m_pFormDict || !pPage->m_pFormDict->KeyExist("Type")
+	if (!pPage || !pPage->m_pFormDict || !pPage->m_pFormDict->KeyExist("Type") || !pPage->m_pFormDict->GetElement("Type")->GetDirect()
 		|| pPage->m_pFormDict->GetElement("Type")->GetDirect()->GetString().Compare("Page"))
 	{
 		return;
@@ -199,7 +199,7 @@
 DLLEXPORT int STDCALL FPDFPage_CountObject(FPDF_PAGE page)
 {
 	CPDF_Page* pPage = (CPDF_Page*)page;
-	if (!pPage || !pPage->m_pFormDict || !pPage->m_pFormDict->KeyExist("Type")
+	if (!pPage || !pPage->m_pFormDict || !pPage->m_pFormDict->KeyExist("Type") || !pPage->m_pFormDict->GetElement("Type")->GetDirect()
 		|| pPage->m_pFormDict->GetElement("Type")->GetDirect()->GetString().Compare("Page"))
 	{
 		return -1;
@@ -263,7 +263,7 @@
 DLLEXPORT FPDF_BOOL STDCALL FPDFPage_GenerateContent(FPDF_PAGE page)
 {
 	CPDF_Page* pPage = (CPDF_Page*)page;
-	if (!pPage || !pPage->m_pFormDict || !pPage->m_pFormDict->KeyExist("Type")
+	if (!pPage || !pPage->m_pFormDict || !pPage->m_pFormDict->KeyExist("Type") || !pPage->m_pFormDict->GetElement("Type")->GetDirect()
 		|| pPage->m_pFormDict->GetElement("Type")->GetDirect()->GetString().Compare("Page"))
 	{
 		return FALSE;
@@ -318,7 +318,7 @@
 DLLEXPORT void STDCALL FPDFPage_SetRotation(FPDF_PAGE page, int rotate)
 {
 	CPDF_Page* pPage = (CPDF_Page*)page;
-	if (!pPage || !pPage->m_pFormDict || !pPage->m_pFormDict->KeyExist("Type")
+	if (!pPage || !pPage->m_pFormDict || !pPage->m_pFormDict->KeyExist("Type") || !pPage->m_pFormDict->GetElement("Type")->GetDirect()
 		|| pPage->m_pFormDict->GetElement("Type")->GetDirect()->GetString().Compare("Page"))
 	{
 		return;
diff --git a/fpdfsdk/src/fpdfppo.cpp b/fpdfsdk/src/fpdfppo.cpp
index a803454..032c3db 100644
--- a/fpdfsdk/src/fpdfppo.cpp
+++ b/fpdfsdk/src/fpdfppo.cpp
@@ -64,7 +64,7 @@
 		pNewRoot->SetAt("Type", new CPDF_Name("Catalog"));
 	}
 	
-	CPDF_Dictionary* pNewPages = (CPDF_Dictionary*)pNewRoot->GetElement("Pages")->GetDirect();
+	CPDF_Dictionary* pNewPages = (CPDF_Dictionary*)(pNewRoot->GetElement("Pages")? pNewRoot->GetElement("Pages")->GetDirect() : NULL);
 	if(!pNewPages)
 	{
 		pNewPages = new CPDF_Dictionary;
@@ -311,7 +311,8 @@
 	else
 	{
 		CPDF_Object* pClone  = pRef->GetDirect()->Clone();
-		if(!pClone)			return 0;
+		if(!pClone)			
+			return 0;
 		
 		if(pClone->GetType() == PDFOBJ_DICTIONARY)
 		{
diff --git a/fpdfsdk/src/pdfwindow/PWL_Icon.cpp b/fpdfsdk/src/pdfwindow/PWL_Icon.cpp
index b85b845..5e3e6e5 100644
--- a/fpdfsdk/src/pdfwindow/PWL_Icon.cpp
+++ b/fpdfsdk/src/pdfwindow/PWL_Icon.cpp
@@ -160,7 +160,7 @@
 		//m_pIconFit->GetIconPosition(fLeft,fBottom);
 		fLeft = 0.0f;
 		fBottom = 0.0f;
-		CPDF_Array* pA = m_pIconFit->m_pDict->GetArray("A");
+		CPDF_Array* pA = m_pIconFit->m_pDict ? m_pIconFit->m_pDict->GetArray("A") : NULL;
 		if (pA != NULL)
 		{
 			FX_DWORD dwCount = pA->GetCount();