Revert of Unify some code

core/fpdfapi/parser/cpdf_data_avail.cpp

Index: core/fpdfapi/parser/cpdf_data_avail.cpp
diff --git a/core/fpdfapi/parser/cpdf_data_avail.cpp b/core/fpdfapi/parser/cpdf_data_avail.cpp
index e6d2c61ad384dbc4c3d104882648d6c9299cbc29..c4ed95e17f27d344afdede77d2c756d91a43aa35 100644
--- a/core/fpdfapi/parser/cpdf_data_avail.cpp
+++ b/core/fpdfapi/parser/cpdf_data_avail.cpp
@@ -15,7 +15,6 @@
 #include "core/fpdfapi/parser/cpdf_dictionary.h"
 #include "core/fpdfapi/parser/cpdf_document.h"
 #include "core/fpdfapi/parser/cpdf_hint_tables.h"
-#include "core/fpdfapi/parser/cpdf_linearized.h"
 #include "core/fpdfapi/parser/cpdf_name.h"
 #include "core/fpdfapi/parser/cpdf_number.h"
 #include "core/fpdfapi/parser/cpdf_reference.h"
@@ -44,6 +43,7 @@
   m_dwCurrentOffset = 0;
   m_dwXRefOffset = 0;
   m_bufferOffset = 0;
+  m_dwFirstPageNo = 0;
   m_bufferSize = 0;
   m_PagesObjNum = 0;
   m_dwCurrentXRefSteam = 0;
@@ -56,6 +56,7 @@
   m_bDocAvail = false;
   m_bMainXRefLoadTried = false;
   m_bDocAvail = false;
+  m_bLinearized = false;
   m_bPagesLoad = false;
   m_bPagesTreeLoad = false;
   m_bMainXRefLoadedOK = false;
@@ -65,6 +66,7 @@
   m_bPageLoadedOK = false;
   m_bNeedDownLoadResource = false;
   m_bLinearizedFormParamLoad = false;
+  m_pLinearized = nullptr;
   m_pRoot = nullptr;
   m_pTrailer = nullptr;
   m_pCurrentParser = nullptr;
@@ -81,6 +83,9 @@
 
 CPDF_DataAvail::~CPDF_DataAvail() {
   m_pHintTables.reset();
+  delete m_pLinearized;
+  delete m_pRoot;
+  delete m_pTrailer;
 
   for (CPDF_Object* pObject : m_arrayAcroforms)
     delete pObject;
@@ -608,27 +613,48 @@
 }
 
 bool CPDF_DataAvail::CheckFirstPage(DownloadHints* pHints) {
-  if (!m_pLinearized->GetFirstPageEndOffset() ||
-      !m_pLinearized->GetFileSize() || !m_pLinearized->GetLastXRefOffset()) {
+  CPDF_Dictionary* pDict = m_pLinearized->GetDict();
+  CPDF_Object* pEndOffSet = pDict ? pDict->GetObjectFor("E") : nullptr;
+  if (!pEndOffSet) {
+    m_docStatus = PDF_DATAAVAIL_ERROR;
+    return false;
+  }
+
+  CPDF_Object* pXRefOffset = pDict ? pDict->GetObjectFor("T") : nullptr;
+  if (!pXRefOffset) {
+    m_docStatus = PDF_DATAAVAIL_ERROR;
+    return false;
+  }
+
+  CPDF_Object* pFileLen = pDict ? pDict->GetObjectFor("L") : nullptr;
+  if (!pFileLen) {
     m_docStatus = PDF_DATAAVAIL_ERROR;
     return false;
   }
 
   bool bNeedDownLoad = false;
-  uint32_t dwEnd = m_pLinearized->GetFirstPageEndOffset();
-  dwEnd += 512;
-  if ((FX_FILESIZE)dwEnd > m_dwFileLen)
-    dwEnd = (uint32_t)m_dwFileLen;
-
-  int32_t iStartPos = (int32_t)(m_dwFileLen > 1024 ? 1024 : m_dwFileLen);
-  int32_t iSize = dwEnd > 1024 ? dwEnd - 1024 : 0;
-  if (!m_pFileAvail->IsDataAvail(iStartPos, iSize)) {
-    pHints->AddSegment(iStartPos, iSize);
-    bNeedDownLoad = true;
-  }
-
-  m_dwLastXRefOffset = m_pLinearized->GetLastXRefOffset();
-  FX_FILESIZE dwFileLen = m_pLinearized->GetFileSize();
+  if (pEndOffSet->IsNumber()) {
+    uint32_t dwEnd = pEndOffSet->GetInteger();
+    dwEnd += 512;
+    if ((FX_FILESIZE)dwEnd > m_dwFileLen)
+      dwEnd = (uint32_t)m_dwFileLen;
+
+    int32_t iStartPos = (int32_t)(m_dwFileLen > 1024 ? 1024 : m_dwFileLen);
+    int32_t iSize = dwEnd > 1024 ? dwEnd - 1024 : 0;
+    if (!m_pFileAvail->IsDataAvail(iStartPos, iSize)) {
+      pHints->AddSegment(iStartPos, iSize);
+      bNeedDownLoad = true;
+    }
+  }
+
+  m_dwLastXRefOffset = 0;
+  FX_FILESIZE dwFileLen = 0;
+  if (pXRefOffset->IsNumber())
+    m_dwLastXRefOffset = pXRefOffset->GetInteger();
+
+  if (pFileLen->IsNumber())
+    dwFileLen = pFileLen->GetInteger();
+
   if (!m_pFileAvail->IsDataAvail(m_dwLastXRefOffset,
                                  (uint32_t)(dwFileLen - m_dwLastXRefOffset))) {
     if (m_docStatus == PDF_DATAAVAIL_FIRSTPAGE) {
@@ -676,17 +702,52 @@
 }
 
 bool CPDF_DataAvail::CheckHintTables(DownloadHints* pHints) {
-  if (m_pLinearized->GetPageCount() <= 1) {
+  CPDF_Dictionary* pDict = m_pLinearized->GetDict();
+  if (!pDict) {
+    m_docStatus = PDF_DATAAVAIL_ERROR;
+    return false;
+  }
+
+  // The actual value is not required here, but validate its existence and type.
+  CPDF_Number* pFirstPage = ToNumber(pDict->GetDirectObjectFor("O"));
+  if (!pFirstPage || !pFirstPage->IsInteger()) {
+    m_docStatus = PDF_DATAAVAIL_ERROR;
+    return false;
+  }
+
+  CPDF_Number* pPageCount = ToNumber(pDict->GetDirectObjectFor("N"));
+  if (!pPageCount || !pPageCount->IsInteger()) {
+    m_docStatus = PDF_DATAAVAIL_ERROR;
+    return false;
+  }
+
+  int nPageCount = pPageCount->GetInteger();
+  if (nPageCount <= 1) {
     m_docStatus = PDF_DATAAVAIL_DONE;
     return true;
   }
-  if (!m_pLinearized->HasHintTable()) {
-    m_docStatus = PDF_DATAAVAIL_ERROR;
-    return false;
-  }
-
-  FX_FILESIZE szHintStart = m_pLinearized->GetHintStart();
-  FX_FILESIZE szHintLength = m_pLinearized->GetHintLength();
+
+  CPDF_Array* pHintStreamRange = pDict->GetArrayFor("H");
+  size_t nHintStreamSize = pHintStreamRange ? pHintStreamRange->GetCount() : 0;
+  if (nHintStreamSize != 2 && nHintStreamSize != 4) {
+    m_docStatus = PDF_DATAAVAIL_ERROR;
+    return false;
+  }
+
+  for (const CPDF_Object* pArrayObject : *pHintStreamRange) {
+    const CPDF_Number* pNumber = ToNumber(pArrayObject->GetDirect());
+    if (!pNumber || !pNumber->IsInteger()) {
+      m_docStatus = PDF_DATAAVAIL_ERROR;
+      return false;
+    }
+  }
+
+  FX_FILESIZE szHintStart = pHintStreamRange->GetIntegerAt(0);
+  FX_FILESIZE szHintLength = pHintStreamRange->GetIntegerAt(1);
+  if (szHintStart < 0 || szHintLength <= 0) {
+    m_docStatus = PDF_DATAAVAIL_ERROR;
+    return false;
+  }
 
   if (!IsDataAvail(szHintStart, szHintLength, pHints))
     return false;
@@ -694,7 +755,7 @@
   m_syntaxParser.InitParser(m_pFileRead, m_dwHeaderOffset);
 
   std::unique_ptr<CPDF_HintTables> pHintTables(
-      new CPDF_HintTables(this, m_pLinearized.get()));
+      new CPDF_HintTables(this, pDict));
   std::unique_ptr<CPDF_Object> pHintStream(
       ParseIndirectObjectAt(szHintStart, 0));
   CPDF_Stream* pStream = ToStream(pHintStream.get());
@@ -758,12 +819,12 @@
 }
 
 bool CPDF_DataAvail::IsLinearized() {
-  return !!m_pLinearized;
+  return m_bLinearized;
 }
 
 bool CPDF_DataAvail::IsLinearizedFile(uint8_t* pData, uint32_t dwLen) {
   if (m_pLinearized)
-    return true;
+    return m_bLinearized;
 
   ScopedFileStream file(FX_CreateMemoryStream(pData, (size_t)dwLen, false));
 
@@ -783,13 +844,27 @@
     return false;
 
   uint32_t objnum = FXSYS_atoui(wordObjNum.c_str());
-  m_pLinearized = CPDF_Linearized::CreateForObject(pdfium::WrapUnique(
-      ParseIndirectObjectAt(m_syntaxParser.m_HeaderOffset + 9, objnum)));
-  if (!m_pLinearized ||
-      m_pLinearized->GetFileSize() != m_pFileRead->GetSize()) {
-    m_pLinearized.reset();
-    return false;
-  }
+  m_pLinearized =
+      ParseIndirectObjectAt(m_syntaxParser.m_HeaderOffset + 9, objnum);
+  if (!m_pLinearized)
+    return false;
+
+  CPDF_Dictionary* pDict = m_pLinearized->GetDict();
+  if (!pDict || !pDict->GetObjectFor("Linearized"))
+    return false;
+
+  CPDF_Object* pLen = pDict->GetObjectFor("L");
+  if (!pLen)
+    return false;
+
+  if ((FX_FILESIZE)pLen->GetInteger() != m_pFileRead->GetSize())
+    return false;
+
+  m_bLinearized = true;
+
+  if (CPDF_Number* pNo = ToNumber(pDict->GetObjectFor("P")))
+    m_dwFirstPageNo = pNo->GetInteger();
+
   return true;
 }
 
@@ -1525,8 +1600,8 @@
   if (pdfium::ContainsKey(m_pagesLoadState, dwPage))
     return DataAvailable;
 
-  if (m_pLinearized) {
-    if (dwPage == m_pLinearized->GetFirstPageNo()) {
+  if (m_bLinearized) {
+    if (dwPage == m_dwFirstPageNo) {
       DocAvailStatus nRet = CheckLinearizedFirstPage(dwPage, pHints);
       if (nRet == DataAvailable)
         m_pagesLoadState.insert(dwPage);
@@ -1656,8 +1731,11 @@
 }
 
 int CPDF_DataAvail::GetPageCount() const {
-  if (m_pLinearized)
-    return m_pLinearized->GetPageCount();
+  if (m_pLinearized) {
+    CPDF_Dictionary* pDict = m_pLinearized->GetDict();
+    CPDF_Object* pObj = pDict ? pDict->GetDirectObjectFor("N") : nullptr;
+    return pObj ? pObj->GetInteger() : 0;
+  }
   return m_pDocument ? m_pDocument->GetPageCount() : 0;
 }
 
@@ -1670,7 +1748,10 @@
   if (!m_pLinearized || !m_pHintTables)
     return nullptr;
 
-  if (index == static_cast<int>(m_pLinearized->GetFirstPageNo()))
+  CPDF_Dictionary* pDict = m_pLinearized->GetDict();
+  CPDF_Object* pObj = pDict ? pDict->GetDirectObjectFor("P") : nullptr;
+  int firstPageNum = pObj ? pObj->GetInteger() : 0;
+  if (index == firstPageNum)
     return nullptr;
   FX_FILESIZE szPageStartPos = 0;
   FX_FILESIZE szPageLength = 0;