Cleanup CFX_BlockBuffer

This CL cleans up default parameters, return values and bits of code
formatting in the CFX_BlockBuffer code.

Change-Id: Ie7fd7d86046f716d0786213735ad464eefc58dbb
Reviewed-on: https://pdfium-review.googlesource.com/3670
Commit-Queue: dsinclair <dsinclair@chromium.org>
Reviewed-by: Nicolás Peña <npm@chromium.org>
Reviewed-by: Tom Sepez <tsepez@chromium.org>

4 files changed, 154 insertions, 156 deletions

diff --git a/core/fxcrt/cfx_blockbuffer.cpp b/core/fxcrt/cfx_blockbuffer.cpp
index 354f415282..efae014982 100644
--- a/core/fxcrt/cfx_blockbuffer.cpp
+++ b/core/fxcrt/cfx_blockbuffer.cpp
@@ -7,57 +7,58 @@
 #include "core/fxcrt/cfx_blockbuffer.h"
 
 #include <algorithm>
+#include <utility>
 
 #include "third_party/base/stl_util.h"
 
-CFX_BlockBuffer::CFX_BlockBuffer(int32_t iAllocStep)
-    : m_iDataLength(0),
-      m_iBufferSize(0),
-      m_iAllocStep(iAllocStep),
-      m_iStartPosition(0) {}
+namespace {
 
-CFX_BlockBuffer::~CFX_BlockBuffer() {
-  ClearBuffer();
+const int kAllocStep = 1024 * 1024;
+
+}  // namespace
+
+CFX_BlockBuffer::CFX_BlockBuffer()
+    : m_iDataLength(0), m_iBufferSize(0), m_iStartPosition(0) {}
+
+CFX_BlockBuffer::~CFX_BlockBuffer() {}
+
+int32_t CFX_BlockBuffer::GetAllocStep() const {
+  return kAllocStep;
 }
 
-wchar_t* CFX_BlockBuffer::GetAvailableBlock(int32_t& iIndexInBlock) {
-  iIndexInBlock = 0;
+std::pair<wchar_t*, int32_t> CFX_BlockBuffer::GetAvailableBlock() {
   if (m_BlockArray.empty())
-    return nullptr;
+    return {nullptr, 0};
 
   int32_t iRealIndex = m_iStartPosition + m_iDataLength;
   if (iRealIndex == m_iBufferSize) {
-    m_BlockArray.emplace_back(FX_Alloc(wchar_t, m_iAllocStep));
-    m_iBufferSize += m_iAllocStep;
-    return m_BlockArray.back().get();
+    m_BlockArray.emplace_back(FX_Alloc(wchar_t, kAllocStep));
+    m_iBufferSize += kAllocStep;
+    return {m_BlockArray.back().get(), 0};
   }
-  iIndexInBlock = iRealIndex % m_iAllocStep;
-  return m_BlockArray[iRealIndex / m_iAllocStep].get();
+  return {m_BlockArray[iRealIndex / kAllocStep].get(), iRealIndex % kAllocStep};
 }
 
-bool CFX_BlockBuffer::InitBuffer(int32_t iBufferSize) {
-  ClearBuffer();
-  int32_t iNumOfBlock = (iBufferSize - 1) / m_iAllocStep + 1;
-  for (int32_t i = 0; i < iNumOfBlock; i++)
-    m_BlockArray.emplace_back(FX_Alloc(wchar_t, m_iAllocStep));
-
-  m_iBufferSize = iNumOfBlock * m_iAllocStep;
+bool CFX_BlockBuffer::InitBuffer() {
+  m_BlockArray.clear();
+  m_BlockArray.emplace_back(FX_Alloc(wchar_t, kAllocStep));
+  m_iBufferSize = kAllocStep;
   return true;
 }
 
 void CFX_BlockBuffer::SetTextChar(int32_t iIndex, wchar_t ch) {
-  if (iIndex < 0) {
+  if (iIndex < 0)
     return;
-  }
+
   int32_t iRealIndex = m_iStartPosition + iIndex;
-  int32_t iBlockIndex = iRealIndex / m_iAllocStep;
-  int32_t iInnerIndex = iRealIndex % m_iAllocStep;
+  int32_t iBlockIndex = iRealIndex / kAllocStep;
+  int32_t iInnerIndex = iRealIndex % kAllocStep;
   int32_t iBlockSize = pdfium::CollectionSize<int32_t>(m_BlockArray);
   if (iBlockIndex >= iBlockSize) {
     int32_t iNewBlocks = iBlockIndex - iBlockSize + 1;
     do {
-      m_BlockArray.emplace_back(FX_Alloc(wchar_t, m_iAllocStep));
-      m_iBufferSize += m_iAllocStep;
+      m_BlockArray.emplace_back(FX_Alloc(wchar_t, kAllocStep));
+      m_iBufferSize += kAllocStep;
     } while (--iNewBlocks);
   }
   wchar_t* pTextData = m_BlockArray[iBlockIndex].get();
@@ -65,7 +66,7 @@ void CFX_BlockBuffer::SetTextChar(int32_t iIndex, wchar_t ch) {
   m_iDataLength = std::max(m_iDataLength, iIndex + 1);
 }
 
-int32_t CFX_BlockBuffer::DeleteTextChars(int32_t iCount, bool bDirection) {
+int32_t CFX_BlockBuffer::DeleteTextChars(int32_t iCount) {
   if (iCount <= 0)
     return m_iDataLength;
 
@@ -73,68 +74,57 @@ int32_t CFX_BlockBuffer::DeleteTextChars(int32_t iCount, bool bDirection) {
     Reset(false);
     return 0;
   }
-  if (bDirection) {
-    m_iStartPosition += iCount;
-    m_iDataLength -= iCount;
-  } else {
-    m_iDataLength -= iCount;
-  }
+  m_iDataLength -= iCount;
   return m_iDataLength;
 }
 
-void CFX_BlockBuffer::GetTextData(CFX_WideString& wsTextData,
-                                  int32_t iStart,
-                                  int32_t iLength) const {
-  wsTextData.clear();
+CFX_WideString CFX_BlockBuffer::GetTextData(int32_t iStart,
+                                            int32_t iLength) const {
   int32_t iMaybeDataLength = m_iBufferSize - 1 - m_iStartPosition;
-  if (iStart < 0 || iStart > iMaybeDataLength) {
-    return;
-  }
-  if (iLength == -1 || iLength > iMaybeDataLength) {
+  if (iStart < 0 || iStart > iMaybeDataLength)
+    return CFX_WideString();
+  if (iLength == -1 || iLength > iMaybeDataLength)
     iLength = iMaybeDataLength;
-  }
-  if (iLength <= 0) {
-    return;
-  }
+  if (iLength <= 0)
+    return CFX_WideString();
+
+  CFX_WideString wsTextData;
   wchar_t* pBuf = wsTextData.GetBuffer(iLength);
-  if (!pBuf) {
-    return;
-  }
-  int32_t iStartBlockIndex = 0;
-  int32_t iStartInnerIndex = 0;
-  TextDataIndex2BufIndex(iStart, iStartBlockIndex, iStartInnerIndex);
-  int32_t iEndBlockIndex = 0;
-  int32_t iEndInnerIndex = 0;
-  TextDataIndex2BufIndex(iStart + iLength, iEndBlockIndex, iEndInnerIndex);
+  if (!pBuf)
+    return CFX_WideString();
+
+  int32_t iStartBlock = 0;
+  int32_t iStartInner = 0;
+  std::tie(iStartBlock, iStartInner) = TextDataIndex2BufIndex(iStart);
+
+  int32_t iEndBlock = 0;
+  int32_t iEndInner = 0;
+  std::tie(iEndBlock, iEndInner) = TextDataIndex2BufIndex(iStart + iLength);
+
   int32_t iPointer = 0;
-  for (int32_t i = iStartBlockIndex; i <= iEndBlockIndex; i++) {
+  for (int32_t i = iStartBlock; i <= iEndBlock; i++) {
     int32_t iBufferPointer = 0;
-    int32_t iCopyLength = m_iAllocStep;
-    if (i == iStartBlockIndex) {
-      iCopyLength -= iStartInnerIndex;
-      iBufferPointer = iStartInnerIndex;
-    }
-    if (i == iEndBlockIndex) {
-      iCopyLength -= ((m_iAllocStep - 1) - iEndInnerIndex);
+    int32_t iCopyLength = kAllocStep;
+    if (i == iStartBlock) {
+      iCopyLength -= iStartInner;
+      iBufferPointer = iStartInner;
     }
+    if (i == iEndBlock)
+      iCopyLength -= ((kAllocStep - 1) - iEndInner);
+
     wchar_t* pBlockBuf = m_BlockArray[i].get();
     memcpy(pBuf + iPointer, pBlockBuf + iBufferPointer,
            iCopyLength * sizeof(wchar_t));
     iPointer += iCopyLength;
   }
   wsTextData.ReleaseBuffer(iLength);
+  return wsTextData;
 }
 
-void CFX_BlockBuffer::TextDataIndex2BufIndex(const int32_t iIndex,
-                                             int32_t& iBlockIndex,
-                                             int32_t& iInnerIndex) const {
+std::pair<int32_t, int32_t> CFX_BlockBuffer::TextDataIndex2BufIndex(
+    const int32_t iIndex) const {
   ASSERT(iIndex >= 0);
-  int32_t iRealIndex = m_iStartPosition + iIndex;
-  iBlockIndex = iRealIndex / m_iAllocStep;
-  iInnerIndex = iRealIndex % m_iAllocStep;
-}
 
-void CFX_BlockBuffer::ClearBuffer() {
-  m_iBufferSize = 0;
-  m_BlockArray.clear();
+  int32_t iRealIndex = m_iStartPosition + iIndex;
+  return {iRealIndex / kAllocStep, iRealIndex % kAllocStep};
 }
diff --git a/core/fxcrt/cfx_blockbuffer.h b/core/fxcrt/cfx_blockbuffer.h
index dbf01a938a..e7e493ca86 100644
--- a/core/fxcrt/cfx_blockbuffer.h
+++ b/core/fxcrt/cfx_blockbuffer.h
@@ -10,44 +10,43 @@
 #include <stdint.h>
 
 #include <memory>
+#include <utility>
 #include <vector>
 
 #include "core/fxcrt/fx_string.h"
 
 class CFX_BlockBuffer {
  public:
-  explicit CFX_BlockBuffer(int32_t iAllocStep = 1024 * 1024);
+  CFX_BlockBuffer();
   ~CFX_BlockBuffer();
 
-  bool InitBuffer(int32_t iBufferSize = 1024 * 1024);
-  bool IsInitialized() { return m_iBufferSize / m_iAllocStep >= 1; }
+  bool InitBuffer();
+  bool IsInitialized() { return m_iBufferSize / GetAllocStep() >= 1; }
 
-  wchar_t* GetAvailableBlock(int32_t& iIndexInBlock);
-  inline int32_t GetAllocStep() const { return m_iAllocStep; }
-  inline int32_t& GetDataLengthRef() { return m_iDataLength; }
+  std::pair<wchar_t*, int32_t> GetAvailableBlock();
+  int32_t GetAllocStep() const;
 
-  inline void Reset(bool bReserveData = true) {
+  // This is ... scary. This returns a ref, which the XMLSyntaxParser stores
+  // and modifies.
+  int32_t& GetDataLengthRef() { return m_iDataLength; }
+
+  void Reset(bool bReserveData) {
     if (!bReserveData)
       m_iStartPosition = 0;
     m_iDataLength = 0;
   }
 
   void SetTextChar(int32_t iIndex, wchar_t ch);
-  int32_t DeleteTextChars(int32_t iCount, bool bDirection = true);
-  void GetTextData(CFX_WideString& wsTextData,
-                   int32_t iStart = 0,
-                   int32_t iLength = -1) const;
+  int32_t DeleteTextChars(int32_t iCount);
+  CFX_WideString GetTextData(int32_t iStart, int32_t iLength) const;
 
  private:
-  inline void TextDataIndex2BufIndex(const int32_t iIndex,
-                                     int32_t& iBlockIndex,
-                                     int32_t& iInnerIndex) const;
-  void ClearBuffer();
+  std::pair<int32_t, int32_t> TextDataIndex2BufIndex(
+      const int32_t iIndex) const;
 
   std::vector<std::unique_ptr<wchar_t, FxFreeDeleter>> m_BlockArray;
   int32_t m_iDataLength;
   int32_t m_iBufferSize;
-  int32_t m_iAllocStep;
   int32_t m_iStartPosition;
 };
 
diff --git a/xfa/fde/xml/cfde_xmlsyntaxparser.cpp b/xfa/fde/xml/cfde_xmlsyntaxparser.cpp
index 45a1eddb83..b4f9a211a7 100644
--- a/xfa/fde/xml/cfde_xmlsyntaxparser.cpp
+++ b/xfa/fde/xml/cfde_xmlsyntaxparser.cpp
@@ -126,9 +126,11 @@ void CFDE_XMLSyntaxParser::Init(const CFX_RetainPtr<IFGAS_Stream>& pStream,
   m_pBuffer = FX_Alloc(
       wchar_t, pdfium::base::ValueOrDieForType<size_t>(alloc_size_safe));
   m_pStart = m_pEnd = m_pBuffer;
+
   ASSERT(!m_BlockBuffer.IsInitialized());
   m_BlockBuffer.InitBuffer();
-  m_pCurrentBlock = m_BlockBuffer.GetAvailableBlock(m_iIndexInBlock);
+  std::tie(m_pCurrentBlock, m_iIndexInBlock) =
+      m_BlockBuffer.GetAvailableBlock();
   m_iParsedBytes = m_iParsedChars = 0;
   m_iBufferChars = 0;
 }
@@ -174,9 +176,9 @@ FDE_XmlSyntaxResult CFDE_XMLSyntaxParser::DoSyntaxParse() {
           if (ch == L'<') {
             if (m_iDataLength > 0) {
               m_iTextDataLength = m_iDataLength;
-              m_BlockBuffer.Reset();
-              m_pCurrentBlock =
-                  m_BlockBuffer.GetAvailableBlock(m_iIndexInBlock);
+              m_BlockBuffer.Reset(true);
+              std::tie(m_pCurrentBlock, m_iIndexInBlock) =
+                  m_BlockBuffer.GetAvailableBlock();
               m_iEntityStart = -1;
               syntaxParserResult = FDE_XmlSyntaxResult::Text;
             } else {
@@ -221,9 +223,9 @@ FDE_XmlSyntaxResult CFDE_XMLSyntaxParser::DoSyntaxParse() {
               return m_syntaxParserResult;
             } else {
               m_iTextDataLength = m_iDataLength;
-              m_BlockBuffer.Reset();
-              m_pCurrentBlock =
-                  m_BlockBuffer.GetAvailableBlock(m_iIndexInBlock);
+              m_BlockBuffer.Reset(true);
+              std::tie(m_pCurrentBlock, m_iIndexInBlock) =
+                  m_BlockBuffer.GetAvailableBlock();
               if (m_syntaxParserState != FDE_XmlSyntaxState::Target) {
                 syntaxParserResult = FDE_XmlSyntaxResult::TagName;
               } else {
@@ -233,8 +235,8 @@ FDE_XmlSyntaxResult CFDE_XMLSyntaxParser::DoSyntaxParse() {
             }
           } else {
             if (m_iIndexInBlock == m_iAllocStep) {
-              m_pCurrentBlock =
-                  m_BlockBuffer.GetAvailableBlock(m_iIndexInBlock);
+              std::tie(m_pCurrentBlock, m_iIndexInBlock) =
+                  m_BlockBuffer.GetAvailableBlock();
               if (!m_pCurrentBlock) {
                 return FDE_XmlSyntaxResult::Error;
               }
@@ -275,16 +277,16 @@ FDE_XmlSyntaxResult CFDE_XMLSyntaxParser::DoSyntaxParse() {
                 }
               }
               m_iTextDataLength = m_iDataLength;
-              m_BlockBuffer.Reset();
-              m_pCurrentBlock =
-                  m_BlockBuffer.GetAvailableBlock(m_iIndexInBlock);
+              m_BlockBuffer.Reset(true);
+              std::tie(m_pCurrentBlock, m_iIndexInBlock) =
+                  m_BlockBuffer.GetAvailableBlock();
               m_syntaxParserState = FDE_XmlSyntaxState::AttriEqualSign;
               syntaxParserResult = FDE_XmlSyntaxResult::AttriName;
             }
           } else {
             if (m_iIndexInBlock == m_iAllocStep) {
-              m_pCurrentBlock =
-                  m_BlockBuffer.GetAvailableBlock(m_iIndexInBlock);
+              std::tie(m_pCurrentBlock, m_iIndexInBlock) =
+                  m_BlockBuffer.GetAvailableBlock();
               if (!m_pCurrentBlock) {
                 return FDE_XmlSyntaxResult::Error;
               }
@@ -333,8 +335,9 @@ FDE_XmlSyntaxResult CFDE_XMLSyntaxParser::DoSyntaxParse() {
             }
             m_iTextDataLength = m_iDataLength;
             m_wQuotationMark = 0;
-            m_BlockBuffer.Reset();
-            m_pCurrentBlock = m_BlockBuffer.GetAvailableBlock(m_iIndexInBlock);
+            m_BlockBuffer.Reset(true);
+            std::tie(m_pCurrentBlock, m_iIndexInBlock) =
+                m_BlockBuffer.GetAvailableBlock();
             m_pStart++;
             m_syntaxParserState = FDE_XmlSyntaxState::AttriName;
             syntaxParserResult = FDE_XmlSyntaxResult::AttriValue;
@@ -345,8 +348,8 @@ FDE_XmlSyntaxResult CFDE_XMLSyntaxParser::DoSyntaxParse() {
         case FDE_XmlSyntaxState::CloseInstruction:
           if (ch != L'>') {
             if (m_iIndexInBlock == m_iAllocStep) {
-              m_pCurrentBlock =
-                  m_BlockBuffer.GetAvailableBlock(m_iIndexInBlock);
+              std::tie(m_pCurrentBlock, m_iIndexInBlock) =
+                  m_BlockBuffer.GetAvailableBlock();
               if (!m_pCurrentBlock) {
                 return FDE_XmlSyntaxResult::Error;
               }
@@ -356,8 +359,9 @@ FDE_XmlSyntaxResult CFDE_XMLSyntaxParser::DoSyntaxParse() {
             m_syntaxParserState = FDE_XmlSyntaxState::TargetData;
           } else if (m_iDataLength > 0) {
             m_iTextDataLength = m_iDataLength;
-            m_BlockBuffer.Reset();
-            m_pCurrentBlock = m_BlockBuffer.GetAvailableBlock(m_iIndexInBlock);
+            m_BlockBuffer.Reset(true);
+            std::tie(m_pCurrentBlock, m_iIndexInBlock) =
+                m_BlockBuffer.GetAvailableBlock();
             syntaxParserResult = FDE_XmlSyntaxResult::TargetData;
           } else {
             m_pStart++;
@@ -373,8 +377,9 @@ FDE_XmlSyntaxResult CFDE_XMLSyntaxParser::DoSyntaxParse() {
               m_CurNode.eNodeType = FDE_XMLNODE_Unknown;
             }
             m_iCurrentNodeNum = m_CurNode.iNodeNum;
-            m_BlockBuffer.Reset();
-            m_pCurrentBlock = m_BlockBuffer.GetAvailableBlock(m_iIndexInBlock);
+            m_BlockBuffer.Reset(true);
+            std::tie(m_pCurrentBlock, m_iIndexInBlock) =
+                m_BlockBuffer.GetAvailableBlock();
             m_syntaxParserState = FDE_XmlSyntaxState::Text;
             syntaxParserResult = FDE_XmlSyntaxResult::InstructionClose;
           }
@@ -407,9 +412,9 @@ FDE_XmlSyntaxResult CFDE_XMLSyntaxParser::DoSyntaxParse() {
               }
               m_iCurrentNodeNum = m_CurNode.iNodeNum;
               m_iTextDataLength = m_iDataLength;
-              m_BlockBuffer.Reset();
-              m_pCurrentBlock =
-                  m_BlockBuffer.GetAvailableBlock(m_iIndexInBlock);
+              m_BlockBuffer.Reset(true);
+              std::tie(m_pCurrentBlock, m_iIndexInBlock) =
+                  m_BlockBuffer.GetAvailableBlock();
               m_syntaxParserState = FDE_XmlSyntaxState::Text;
               syntaxParserResult = FDE_XmlSyntaxResult::ElementClose;
             } else if (!IsXMLWhiteSpace(ch)) {
@@ -418,8 +423,8 @@ FDE_XmlSyntaxResult CFDE_XMLSyntaxParser::DoSyntaxParse() {
             }
           } else {
             if (m_iIndexInBlock == m_iAllocStep) {
-              m_pCurrentBlock =
-                  m_BlockBuffer.GetAvailableBlock(m_iIndexInBlock);
+              std::tie(m_pCurrentBlock, m_iIndexInBlock) =
+                  m_BlockBuffer.GetAvailableBlock();
               if (!m_pCurrentBlock) {
                 return FDE_XmlSyntaxResult::Error;
               }
@@ -447,13 +452,14 @@ FDE_XmlSyntaxResult CFDE_XMLSyntaxParser::DoSyntaxParse() {
             m_pStart += 3;
             syntaxParserResult = FDE_XmlSyntaxResult::CData;
             m_iTextDataLength = m_iDataLength;
-            m_BlockBuffer.Reset();
-            m_pCurrentBlock = m_BlockBuffer.GetAvailableBlock(m_iIndexInBlock);
+            m_BlockBuffer.Reset(true);
+            std::tie(m_pCurrentBlock, m_iIndexInBlock) =
+                m_BlockBuffer.GetAvailableBlock();
             m_syntaxParserState = FDE_XmlSyntaxState::Text;
           } else {
             if (m_iIndexInBlock == m_iAllocStep) {
-              m_pCurrentBlock =
-                  m_BlockBuffer.GetAvailableBlock(m_iIndexInBlock);
+              std::tie(m_pCurrentBlock, m_iIndexInBlock) =
+                  m_BlockBuffer.GetAvailableBlock();
               if (!m_pCurrentBlock)
                 return FDE_XmlSyntaxResult::Error;
             }
@@ -500,14 +506,13 @@ FDE_XmlSyntaxResult CFDE_XMLSyntaxParser::DoSyntaxParse() {
                 if (ch == m_SkipChar) {
                   m_SkipStack.pop();
                   if (m_SkipStack.empty()) {
-                    if (m_iDataLength >= 9) {
-                      CFX_WideString wsHeader;
-                      m_BlockBuffer.GetTextData(wsHeader, 0, 7);
-                    }
+                    if (m_iDataLength >= 9)
+                      (void)m_BlockBuffer.GetTextData(0, 7);
+
                     m_iTextDataLength = m_iDataLength;
-                    m_BlockBuffer.Reset();
-                    m_pCurrentBlock =
-                        m_BlockBuffer.GetAvailableBlock(m_iIndexInBlock);
+                    m_BlockBuffer.Reset(true);
+                    std::tie(m_pCurrentBlock, m_iIndexInBlock) =
+                        m_BlockBuffer.GetAvailableBlock();
                     m_syntaxParserState = FDE_XmlSyntaxState::Text;
                   } else {
                     m_SkipChar = m_SkipStack.top();
@@ -517,8 +522,8 @@ FDE_XmlSyntaxResult CFDE_XMLSyntaxParser::DoSyntaxParse() {
             }
             if (!m_SkipStack.empty()) {
               if (m_iIndexInBlock == m_iAllocStep) {
-                m_pCurrentBlock =
-                    m_BlockBuffer.GetAvailableBlock(m_iIndexInBlock);
+                std::tie(m_pCurrentBlock, m_iIndexInBlock) =
+                    m_BlockBuffer.GetAvailableBlock();
                 if (!m_pCurrentBlock) {
                   return FDE_XmlSyntaxResult::Error;
                 }
@@ -545,9 +550,9 @@ FDE_XmlSyntaxResult CFDE_XMLSyntaxParser::DoSyntaxParse() {
             } else if (m_wQuotationMark == 0) {
               m_iTextDataLength = m_iDataLength;
               m_wQuotationMark = 0;
-              m_BlockBuffer.Reset();
-              m_pCurrentBlock =
-                  m_BlockBuffer.GetAvailableBlock(m_iIndexInBlock);
+              m_BlockBuffer.Reset(true);
+              std::tie(m_pCurrentBlock, m_iIndexInBlock) =
+                  m_BlockBuffer.GetAvailableBlock();
               m_pStart++;
               syntaxParserResult = FDE_XmlSyntaxResult::TargetData;
               break;
@@ -563,9 +568,9 @@ FDE_XmlSyntaxResult CFDE_XMLSyntaxParser::DoSyntaxParse() {
             } else if (ch == m_wQuotationMark) {
               m_iTextDataLength = m_iDataLength;
               m_wQuotationMark = 0;
-              m_BlockBuffer.Reset();
-              m_pCurrentBlock =
-                  m_BlockBuffer.GetAvailableBlock(m_iIndexInBlock);
+              m_BlockBuffer.Reset(true);
+              std::tie(m_pCurrentBlock, m_iIndexInBlock) =
+                  m_BlockBuffer.GetAvailableBlock();
               m_pStart++;
               syntaxParserResult = FDE_XmlSyntaxResult::TargetData;
             } else {
@@ -574,8 +579,8 @@ FDE_XmlSyntaxResult CFDE_XMLSyntaxParser::DoSyntaxParse() {
             }
           } else {
             if (m_iIndexInBlock == m_iAllocStep) {
-              m_pCurrentBlock =
-                  m_BlockBuffer.GetAvailableBlock(m_iIndexInBlock);
+              std::tie(m_pCurrentBlock, m_iIndexInBlock) =
+                  m_BlockBuffer.GetAvailableBlock();
               if (!m_pCurrentBlock) {
                 return FDE_XmlSyntaxResult::Error;
               }
@@ -627,17 +632,17 @@ FX_FILESIZE CFDE_XMLSyntaxParser::GetCurrentBinaryPos() const {
 
 void CFDE_XMLSyntaxParser::ParseTextChar(wchar_t character) {
   if (m_iIndexInBlock == m_iAllocStep) {
-    m_pCurrentBlock = m_BlockBuffer.GetAvailableBlock(m_iIndexInBlock);
-    if (!m_pCurrentBlock) {
+    std::tie(m_pCurrentBlock, m_iIndexInBlock) =
+        m_BlockBuffer.GetAvailableBlock();
+    if (!m_pCurrentBlock)
       return;
-    }
   }
+
   m_pCurrentBlock[m_iIndexInBlock++] = character;
   m_iDataLength++;
   if (m_iEntityStart > -1 && character == L';') {
-    CFX_WideString csEntity;
-    m_BlockBuffer.GetTextData(csEntity, m_iEntityStart + 1,
-                              (m_iDataLength - 1) - m_iEntityStart - 1);
+    CFX_WideString csEntity = m_BlockBuffer.GetTextData(
+        m_iEntityStart + 1, (m_iDataLength - 1) - m_iEntityStart - 1);
     int32_t iLen = csEntity.GetLength();
     if (iLen > 0) {
       if (csEntity[0] == L'#') {
@@ -691,13 +696,12 @@ void CFDE_XMLSyntaxParser::ParseTextChar(wchar_t character) {
         }
       }
     }
-    m_BlockBuffer.DeleteTextChars(m_iDataLength - m_iEntityStart, false);
-    m_pCurrentBlock = m_BlockBuffer.GetAvailableBlock(m_iIndexInBlock);
+    m_BlockBuffer.DeleteTextChars(m_iDataLength - m_iEntityStart);
+    std::tie(m_pCurrentBlock, m_iIndexInBlock) =
+        m_BlockBuffer.GetAvailableBlock();
     m_iEntityStart = -1;
-  } else {
-    if (m_iEntityStart < 0 && character == L'&') {
-      m_iEntityStart = m_iDataLength - 1;
-    }
+  } else if (m_iEntityStart < 0 && character == L'&') {
+    m_iEntityStart = m_iDataLength - 1;
   }
   m_pStart++;
 }
diff --git a/xfa/fde/xml/cfde_xmlsyntaxparser.h b/xfa/fde/xml/cfde_xmlsyntaxparser.h
index 9e768d01aa..4f707dc5de 100644
--- a/xfa/fde/xml/cfde_xmlsyntaxparser.h
+++ b/xfa/fde/xml/cfde_xmlsyntaxparser.h
@@ -53,22 +53,27 @@ class CFDE_XMLSyntaxParser {
   int32_t GetLastNodeNumber() const { return m_iLastNodeNum; }
 
   void GetTargetName(CFX_WideString& wsTarget) const {
-    m_BlockBuffer.GetTextData(wsTarget, 0, m_iTextDataLength);
+    wsTarget = m_BlockBuffer.GetTextData(0, m_iTextDataLength);
   }
+
   void GetTagName(CFX_WideString& wsTag) const {
-    m_BlockBuffer.GetTextData(wsTag, 0, m_iTextDataLength);
+    wsTag = m_BlockBuffer.GetTextData(0, m_iTextDataLength);
   }
+
   void GetAttributeName(CFX_WideString& wsAttriName) const {
-    m_BlockBuffer.GetTextData(wsAttriName, 0, m_iTextDataLength);
+    wsAttriName = m_BlockBuffer.GetTextData(0, m_iTextDataLength);
   }
+
   void GetAttributeValue(CFX_WideString& wsAttriValue) const {
-    m_BlockBuffer.GetTextData(wsAttriValue, 0, m_iTextDataLength);
+    wsAttriValue = m_BlockBuffer.GetTextData(0, m_iTextDataLength);
   }
+
   void GetTextData(CFX_WideString& wsText) const {
-    m_BlockBuffer.GetTextData(wsText, 0, m_iTextDataLength);
+    wsText = m_BlockBuffer.GetTextData(0, m_iTextDataLength);
   }
+
   void GetTargetData(CFX_WideString& wsData) const {
-    m_BlockBuffer.GetTextData(wsData, 0, m_iTextDataLength);
+    wsData = m_BlockBuffer.GetTextData(0, m_iTextDataLength);
   }
 
  protected: