Make CPVT_WordPlace more conformant with the prevailing idioms.

Add relational operators to replace CmpWord().
Leave CmpLine() for the moment as it saves some work.
Remove CmpSec() and just inline comparison of the one member.

Invert IsExist() as IsEmpty().  There is a big philosophical
discussion as to whether things that are empty exist.  I say
they do, but they're just empty.

Rename Default() to Reset().  Default sounds like a noun.
Add AdvanceSection() method and call as appropriate.


Change-Id: I01d9479f63a4860e0fd228255540d6d94dc24a9f
Reviewed-on: https://pdfium-review.googlesource.com/3139
Commit-Queue: dsinclair <dsinclair@chromium.org>
Reviewed-by: dsinclair <dsinclair@chromium.org>

4 files changed, 242 insertions, 298 deletions

diff --git a/fpdfsdk/fxedit/fxet_edit.cpp b/fpdfsdk/fxedit/fxet_edit.cpp
index 0a5c3d940f..20f584e183 100644
--- a/fpdfsdk/fxedit/fxet_edit.cpp
+++ b/fpdfsdk/fxedit/fxet_edit.cpp
@@ -459,23 +459,24 @@ CFXEU_Backspace::CFXEU_Backspace(CFX_Edit* pEdit,
 CFXEU_Backspace::~CFXEU_Backspace() {}
 
 void CFXEU_Backspace::Redo() {
-  if (m_pEdit) {
-    m_pEdit->SelectNone();
-    m_pEdit->SetCaret(m_wpOld);
-    m_pEdit->Backspace(false, true);
-  }
+  if (!m_pEdit)
+    return;
+
+  m_pEdit->SelectNone();
+  m_pEdit->SetCaret(m_wpOld);
+  m_pEdit->Backspace(false, true);
 }
 
 void CFXEU_Backspace::Undo() {
-  if (m_pEdit) {
-    m_pEdit->SelectNone();
-    m_pEdit->SetCaret(m_wpNew);
-    if (m_wpNew.SecCmp(m_wpOld) != 0) {
-      m_pEdit->InsertReturn(&m_SecProps, &m_WordProps, false, true);
-    } else {
-      m_pEdit->InsertWord(m_Word, m_nCharset, &m_WordProps, false, true);
-    }
-  }
+  if (!m_pEdit)
+    return;
+
+  m_pEdit->SelectNone();
+  m_pEdit->SetCaret(m_wpNew);
+  if (m_wpNew.nSecIndex != m_wpOld.nSecIndex)
+    m_pEdit->InsertReturn(&m_SecProps, &m_WordProps, false, true);
+  else
+    m_pEdit->InsertWord(m_Word, m_nCharset, &m_WordProps, false, true);
 }
 
 CFXEU_Delete::CFXEU_Delete(CFX_Edit* pEdit,
@@ -591,7 +592,7 @@ CFX_ByteString CFX_Edit::GetEditAppearanceStream(CFX_Edit* pEdit,
 
   while (pIterator->NextWord()) {
     CPVT_WordPlace place = pIterator->GetAt();
-    if (pRange && place.WordCmp(pRange->EndPos) > 0)
+    if (pRange && place > pRange->EndPos)
       break;
 
     if (bContinuous) {
@@ -689,7 +690,7 @@ CFX_ByteString CFX_Edit::GetSelectAppearanceStream(
     CFX_Edit* pEdit,
     const CFX_PointF& ptOffset,
     const CPVT_WordRange* pRange) {
-  if (!pRange || !pRange->IsExist())
+  if (!pRange || pRange->IsEmpty())
     return CFX_ByteString();
 
   CFX_Edit_Iterator* pIterator = pEdit->GetIterator();
@@ -698,7 +699,7 @@ CFX_ByteString CFX_Edit::GetSelectAppearanceStream(
   CFX_ByteTextBuf sRet;
   while (pIterator->NextWord()) {
     CPVT_WordPlace place = pIterator->GetAt();
-    if (place.WordCmp(pRange->EndPos) > 0)
+    if (place > pRange->EndPos)
       break;
 
     CPVT_Word word;
@@ -757,12 +758,11 @@ void CFX_Edit::DrawEdit(CFX_RenderDevice* pDevice,
     CPVT_WordPlace oldplace;
     while (pIterator->NextWord()) {
       CPVT_WordPlace place = pIterator->GetAt();
-      if (pRange && place.WordCmp(pRange->EndPos) > 0)
+      if (pRange && place > pRange->EndPos)
         break;
 
-      if (wrSelect.IsExist()) {
-        bSelect = place.WordCmp(wrSelect.BeginPos) > 0 &&
-                  place.WordCmp(wrSelect.EndPos) <= 0;
+      if (!wrSelect.IsEmpty()) {
+        bSelect = place > wrSelect.BeginPos && place <= wrSelect.EndPos;
         crCurFill = bSelect ? crWhite : crTextFill;
       }
       if (pSystemHandler && pSystemHandler->IsSelectionImplemented()) {
@@ -980,42 +980,36 @@ void CFX_Edit::SetSel(int32_t nStartChar, int32_t nEndChar) {
 }
 
 void CFX_Edit::SetSel(const CPVT_WordPlace& begin, const CPVT_WordPlace& end) {
-  if (m_pVT->IsValid()) {
-    SelectNone();
-
-    m_SelState.Set(begin, end);
-
-    SetCaret(m_SelState.EndPos);
+  if (!m_pVT->IsValid())
+    return;
 
-    if (m_SelState.IsExist()) {
-      ScrollToCaret();
-      Refresh();
-      SetCaretInfo();
-    } else {
-      ScrollToCaret();
-      SetCaretInfo();
-    }
-  }
+  SelectNone();
+  m_SelState.Set(begin, end);
+  SetCaret(m_SelState.EndPos);
+  ScrollToCaret();
+  if (!m_SelState.IsEmpty())
+    Refresh();
+  SetCaretInfo();
 }
 
 void CFX_Edit::GetSel(int32_t& nStartChar, int32_t& nEndChar) const {
   nStartChar = -1;
   nEndChar = -1;
+  if (!m_pVT->IsValid())
+    return;
 
-  if (m_pVT->IsValid()) {
-    if (m_SelState.IsExist()) {
-      if (m_SelState.BeginPos.WordCmp(m_SelState.EndPos) < 0) {
-        nStartChar = m_pVT->WordPlaceToWordIndex(m_SelState.BeginPos);
-        nEndChar = m_pVT->WordPlaceToWordIndex(m_SelState.EndPos);
-      } else {
-        nStartChar = m_pVT->WordPlaceToWordIndex(m_SelState.EndPos);
-        nEndChar = m_pVT->WordPlaceToWordIndex(m_SelState.BeginPos);
-      }
-    } else {
-      nStartChar = m_pVT->WordPlaceToWordIndex(m_wpCaret);
-      nEndChar = m_pVT->WordPlaceToWordIndex(m_wpCaret);
-    }
+  if (m_SelState.IsEmpty()) {
+    nStartChar = m_pVT->WordPlaceToWordIndex(m_wpCaret);
+    nEndChar = m_pVT->WordPlaceToWordIndex(m_wpCaret);
+    return;
   }
+  if (m_SelState.BeginPos < m_SelState.EndPos) {
+    nStartChar = m_pVT->WordPlaceToWordIndex(m_SelState.BeginPos);
+    nEndChar = m_pVT->WordPlaceToWordIndex(m_SelState.EndPos);
+    return;
+  }
+  nStartChar = m_pVT->WordPlaceToWordIndex(m_SelState.EndPos);
+  nEndChar = m_pVT->WordPlaceToWordIndex(m_SelState.BeginPos);
 }
 
 int32_t CFX_Edit::GetCaret() const {
@@ -1031,7 +1025,6 @@ CPVT_WordPlace CFX_Edit::GetCaretWordPlace() const {
 
 CFX_WideString CFX_Edit::GetText() const {
   CFX_WideString swRet;
-
   if (!m_pVT->IsValid())
     return swRet;
 
@@ -1042,22 +1035,17 @@ CFX_WideString CFX_Edit::GetText() const {
   CPVT_WordPlace oldplace = pIterator->GetAt();
   while (pIterator->NextWord()) {
     CPVT_WordPlace place = pIterator->GetAt();
-
     if (pIterator->GetWord(wordinfo))
       swRet += wordinfo.Word;
-
-    if (oldplace.SecCmp(place) != 0)
+    if (oldplace.nSecIndex != place.nSecIndex)
       swRet += L"\r\n";
-
     oldplace = place;
   }
-
   return swRet;
 }
 
 CFX_WideString CFX_Edit::GetRangeText(const CPVT_WordRange& range) const {
   CFX_WideString swRet;
-
   if (!m_pVT->IsValid())
     return swRet;
 
@@ -1071,18 +1059,14 @@ CFX_WideString CFX_Edit::GetRangeText(const CPVT_WordRange& range) const {
   CPVT_WordPlace oldplace = wrTemp.BeginPos;
   while (pIterator->NextWord()) {
     CPVT_WordPlace place = pIterator->GetAt();
-    if (place.WordCmp(wrTemp.EndPos) > 0)
+    if (place > wrTemp.EndPos)
       break;
-
     if (pIterator->GetWord(wordinfo))
       swRet += wordinfo.Word;
-
-    if (oldplace.SecCmp(place) != 0)
+    if (oldplace.nSecIndex != place.nSecIndex)
       swRet += L"\r\n";
-
     oldplace = place;
   }
-
   return swRet;
 }
 
@@ -1242,27 +1226,25 @@ void CFX_Edit::SetContentChanged() {
 }
 
 void CFX_Edit::SelectAll() {
-  if (m_pVT->IsValid()) {
-    m_SelState = CFX_Edit_Select(GetWholeWordRange());
-    SetCaret(m_SelState.EndPos);
-
-    ScrollToCaret();
-    Refresh();
-    SetCaretInfo();
-  }
+  if (!m_pVT->IsValid())
+    return;
+  m_SelState = CFX_Edit_Select(GetWholeWordRange());
+  SetCaret(m_SelState.EndPos);
+  ScrollToCaret();
+  Refresh();
+  SetCaretInfo();
 }
 
 void CFX_Edit::SelectNone() {
-  if (m_pVT->IsValid()) {
-    if (m_SelState.IsExist()) {
-      m_SelState.Default();
-      Refresh();
-    }
-  }
+  if (!m_pVT->IsValid() || m_SelState.IsEmpty())
+    return;
+
+  m_SelState.Reset();
+  Refresh();
 }
 
 bool CFX_Edit::IsSelected() const {
-  return m_SelState.IsExist();
+  return !m_SelState.IsEmpty();
 }
 
 CFX_PointF CFX_Edit::VTToEdit(const CFX_PointF& point) const {
@@ -1520,12 +1502,11 @@ void CFX_Edit::RefreshWordRange(const CPVT_WordRange& wr) {
 
   while (pIterator->NextWord()) {
     place = pIterator->GetAt();
-    if (place.WordCmp(wrTemp.EndPos) > 0)
+    if (place > wrTemp.EndPos)
       break;
 
     pIterator->GetWord(wordinfo);
     pIterator->GetLine(lineinfo);
-
     if (place.LineCmp(wrTemp.BeginPos) == 0 ||
         place.LineCmp(wrTemp.EndPos) == 0) {
       CFX_FloatRect rcWord(wordinfo.ptWord.x,
@@ -1589,7 +1570,7 @@ void CFX_Edit::SetCaretInfo() {
       }
 
       m_bNotifyFlag = true;
-      m_pNotify->IOnSetCaret(!m_SelState.IsExist(), VTToEdit(ptHead),
+      m_pNotify->IOnSetCaret(m_SelState.IsEmpty(), VTToEdit(ptHead),
                              VTToEdit(ptFoot), m_wpCaret);
       m_bNotifyFlag = false;
     }
@@ -1597,256 +1578,246 @@ void CFX_Edit::SetCaretInfo() {
 }
 
 void CFX_Edit::SetCaret(int32_t nPos) {
-  if (m_pVT->IsValid()) {
-    SelectNone();
-    SetCaret(m_pVT->WordIndexToWordPlace(nPos));
-    m_SelState.Set(m_wpCaret, m_wpCaret);
+  if (!m_pVT->IsValid())
+    return;
 
-    ScrollToCaret();
-    SetCaretOrigin();
-    SetCaretInfo();
-  }
+  SelectNone();
+  SetCaret(m_pVT->WordIndexToWordPlace(nPos));
+  m_SelState.Set(m_wpCaret, m_wpCaret);
+  ScrollToCaret();
+  SetCaretOrigin();
+  SetCaretInfo();
 }
 
 void CFX_Edit::OnMouseDown(const CFX_PointF& point, bool bShift, bool bCtrl) {
-  if (m_pVT->IsValid()) {
-    SelectNone();
-    SetCaret(m_pVT->SearchWordPlace(EditToVT(point)));
-    m_SelState.Set(m_wpCaret, m_wpCaret);
+  if (!m_pVT->IsValid())
+    return;
 
-    ScrollToCaret();
-    SetCaretOrigin();
-    SetCaretInfo();
-  }
+  SelectNone();
+  SetCaret(m_pVT->SearchWordPlace(EditToVT(point)));
+  m_SelState.Set(m_wpCaret, m_wpCaret);
+  ScrollToCaret();
+  SetCaretOrigin();
+  SetCaretInfo();
 }
 
 void CFX_Edit::OnMouseMove(const CFX_PointF& point, bool bShift, bool bCtrl) {
-  if (m_pVT->IsValid()) {
-    SetCaret(m_pVT->SearchWordPlace(EditToVT(point)));
+  if (!m_pVT->IsValid())
+    return;
 
-    if (m_wpCaret != m_wpOldCaret) {
-      m_SelState.SetEndPos(m_wpCaret);
+  SetCaret(m_pVT->SearchWordPlace(EditToVT(point)));
+  if (m_wpCaret == m_wpOldCaret)
+    return;
 
-      ScrollToCaret();
-      Refresh();
-      SetCaretOrigin();
-      SetCaretInfo();
-    }
-  }
+  m_SelState.SetEndPos(m_wpCaret);
+  ScrollToCaret();
+  Refresh();
+  SetCaretOrigin();
+  SetCaretInfo();
 }
 
 void CFX_Edit::OnVK_UP(bool bShift, bool bCtrl) {
-  if (m_pVT->IsValid()) {
-    SetCaret(m_pVT->GetUpWordPlace(m_wpCaret, m_ptCaret));
-
-    if (bShift) {
-      if (m_SelState.IsExist())
-        m_SelState.SetEndPos(m_wpCaret);
-      else
-        m_SelState.Set(m_wpOldCaret, m_wpCaret);
+  if (!m_pVT->IsValid())
+    return;
 
-      if (m_wpOldCaret != m_wpCaret) {
-        ScrollToCaret();
-        Refresh();
-        SetCaretInfo();
-      }
-    } else {
-      SelectNone();
+  SetCaret(m_pVT->GetUpWordPlace(m_wpCaret, m_ptCaret));
+  if (bShift) {
+    if (m_SelState.IsEmpty())
+      m_SelState.Set(m_wpOldCaret, m_wpCaret);
+    else
+      m_SelState.SetEndPos(m_wpCaret);
 
+    if (m_wpOldCaret != m_wpCaret) {
       ScrollToCaret();
+      Refresh();
       SetCaretInfo();
     }
+  } else {
+    SelectNone();
+    ScrollToCaret();
+    SetCaretInfo();
   }
 }
 
 void CFX_Edit::OnVK_DOWN(bool bShift, bool bCtrl) {
-  if (m_pVT->IsValid()) {
-    SetCaret(m_pVT->GetDownWordPlace(m_wpCaret, m_ptCaret));
-
-    if (bShift) {
-      if (m_SelState.IsExist())
-        m_SelState.SetEndPos(m_wpCaret);
-      else
-        m_SelState.Set(m_wpOldCaret, m_wpCaret);
+  if (!m_pVT->IsValid())
+    return;
 
-      if (m_wpOldCaret != m_wpCaret) {
-        ScrollToCaret();
-        Refresh();
-        SetCaretInfo();
-      }
-    } else {
-      SelectNone();
+  SetCaret(m_pVT->GetDownWordPlace(m_wpCaret, m_ptCaret));
+  if (bShift) {
+    if (m_SelState.IsEmpty())
+      m_SelState.Set(m_wpOldCaret, m_wpCaret);
+    else
+      m_SelState.SetEndPos(m_wpCaret);
 
+    if (m_wpOldCaret != m_wpCaret) {
       ScrollToCaret();
+      Refresh();
       SetCaretInfo();
     }
+  } else {
+    SelectNone();
+    ScrollToCaret();
+    SetCaretInfo();
   }
 }
 
 void CFX_Edit::OnVK_LEFT(bool bShift, bool bCtrl) {
-  if (m_pVT->IsValid()) {
-    if (bShift) {
-      if (m_wpCaret == m_pVT->GetLineBeginPlace(m_wpCaret) &&
-          m_wpCaret != m_pVT->GetSectionBeginPlace(m_wpCaret))
-        SetCaret(m_pVT->GetPrevWordPlace(m_wpCaret));
+  if (!m_pVT->IsValid())
+    return;
 
+  if (bShift) {
+    if (m_wpCaret == m_pVT->GetLineBeginPlace(m_wpCaret) &&
+        m_wpCaret != m_pVT->GetSectionBeginPlace(m_wpCaret)) {
       SetCaret(m_pVT->GetPrevWordPlace(m_wpCaret));
+    }
+    SetCaret(m_pVT->GetPrevWordPlace(m_wpCaret));
+    if (m_SelState.IsEmpty())
+      m_SelState.Set(m_wpOldCaret, m_wpCaret);
+    else
+      m_SelState.SetEndPos(m_wpCaret);
 
-      if (m_SelState.IsExist())
-        m_SelState.SetEndPos(m_wpCaret);
+    if (m_wpOldCaret != m_wpCaret) {
+      ScrollToCaret();
+      Refresh();
+      SetCaretInfo();
+    }
+  } else {
+    if (!m_SelState.IsEmpty()) {
+      if (m_SelState.BeginPos < m_SelState.EndPos)
+        SetCaret(m_SelState.BeginPos);
       else
-        m_SelState.Set(m_wpOldCaret, m_wpCaret);
+        SetCaret(m_SelState.EndPos);
 
-      if (m_wpOldCaret != m_wpCaret) {
-        ScrollToCaret();
-        Refresh();
-        SetCaretInfo();
-      }
+      SelectNone();
+      ScrollToCaret();
+      SetCaretInfo();
     } else {
-      if (m_SelState.IsExist()) {
-        if (m_SelState.BeginPos.WordCmp(m_SelState.EndPos) < 0)
-          SetCaret(m_SelState.BeginPos);
-        else
-          SetCaret(m_SelState.EndPos);
-
-        SelectNone();
-        ScrollToCaret();
-        SetCaretInfo();
-      } else {
-        if (m_wpCaret == m_pVT->GetLineBeginPlace(m_wpCaret) &&
-            m_wpCaret != m_pVT->GetSectionBeginPlace(m_wpCaret))
-          SetCaret(m_pVT->GetPrevWordPlace(m_wpCaret));
-
+      if (m_wpCaret == m_pVT->GetLineBeginPlace(m_wpCaret) &&
+          m_wpCaret != m_pVT->GetSectionBeginPlace(m_wpCaret)) {
         SetCaret(m_pVT->GetPrevWordPlace(m_wpCaret));
-
-        ScrollToCaret();
-        SetCaretOrigin();
-        SetCaretInfo();
       }
+      SetCaret(m_pVT->GetPrevWordPlace(m_wpCaret));
+      ScrollToCaret();
+      SetCaretOrigin();
+      SetCaretInfo();
     }
   }
 }
 
 void CFX_Edit::OnVK_RIGHT(bool bShift, bool bCtrl) {
-  if (m_pVT->IsValid()) {
-    if (bShift) {
+  if (!m_pVT->IsValid())
+    return;
+
+  if (bShift) {
+    SetCaret(m_pVT->GetNextWordPlace(m_wpCaret));
+    if (m_wpCaret == m_pVT->GetLineEndPlace(m_wpCaret) &&
+        m_wpCaret != m_pVT->GetSectionEndPlace(m_wpCaret))
       SetCaret(m_pVT->GetNextWordPlace(m_wpCaret));
 
-      if (m_wpCaret == m_pVT->GetLineEndPlace(m_wpCaret) &&
-          m_wpCaret != m_pVT->GetSectionEndPlace(m_wpCaret))
-        SetCaret(m_pVT->GetNextWordPlace(m_wpCaret));
+    if (m_SelState.IsEmpty())
+      m_SelState.Set(m_wpOldCaret, m_wpCaret);
+    else
+      m_SelState.SetEndPos(m_wpCaret);
 
-      if (m_SelState.IsExist())
-        m_SelState.SetEndPos(m_wpCaret);
+    if (m_wpOldCaret != m_wpCaret) {
+      ScrollToCaret();
+      Refresh();
+      SetCaretInfo();
+    }
+  } else {
+    if (!m_SelState.IsEmpty()) {
+      if (m_SelState.BeginPos > m_SelState.EndPos)
+        SetCaret(m_SelState.BeginPos);
       else
-        m_SelState.Set(m_wpOldCaret, m_wpCaret);
+        SetCaret(m_SelState.EndPos);
 
-      if (m_wpOldCaret != m_wpCaret) {
-        ScrollToCaret();
-        Refresh();
-        SetCaretInfo();
-      }
+      SelectNone();
+      ScrollToCaret();
+      SetCaretInfo();
     } else {
-      if (m_SelState.IsExist()) {
-        if (m_SelState.BeginPos.WordCmp(m_SelState.EndPos) > 0)
-          SetCaret(m_SelState.BeginPos);
-        else
-          SetCaret(m_SelState.EndPos);
-
-        SelectNone();
-        ScrollToCaret();
-        SetCaretInfo();
-      } else {
+      SetCaret(m_pVT->GetNextWordPlace(m_wpCaret));
+      if (m_wpCaret == m_pVT->GetLineEndPlace(m_wpCaret) &&
+          m_wpCaret != m_pVT->GetSectionEndPlace(m_wpCaret)) {
         SetCaret(m_pVT->GetNextWordPlace(m_wpCaret));
-
-        if (m_wpCaret == m_pVT->GetLineEndPlace(m_wpCaret) &&
-            m_wpCaret != m_pVT->GetSectionEndPlace(m_wpCaret))
-          SetCaret(m_pVT->GetNextWordPlace(m_wpCaret));
-
-        ScrollToCaret();
-        SetCaretOrigin();
-        SetCaretInfo();
       }
+      ScrollToCaret();
+      SetCaretOrigin();
+      SetCaretInfo();
     }
   }
 }
 
 void CFX_Edit::OnVK_HOME(bool bShift, bool bCtrl) {
-  if (m_pVT->IsValid()) {
-    if (bShift) {
+  if (!m_pVT->IsValid())
+    return;
+
+  if (bShift) {
+    if (bCtrl)
+      SetCaret(m_pVT->GetBeginWordPlace());
+    else
+      SetCaret(m_pVT->GetLineBeginPlace(m_wpCaret));
+
+    if (m_SelState.IsEmpty())
+      m_SelState.Set(m_wpOldCaret, m_wpCaret);
+    else
+      m_SelState.SetEndPos(m_wpCaret);
+
+    ScrollToCaret();
+    Refresh();
+    SetCaretInfo();
+  } else {
+    if (!m_SelState.IsEmpty()) {
+      SetCaret(std::min(m_SelState.BeginPos, m_SelState.EndPos));
+      SelectNone();
+      ScrollToCaret();
+      SetCaretInfo();
+    } else {
       if (bCtrl)
         SetCaret(m_pVT->GetBeginWordPlace());
       else
         SetCaret(m_pVT->GetLineBeginPlace(m_wpCaret));
 
-      if (m_SelState.IsExist())
-        m_SelState.SetEndPos(m_wpCaret);
-      else
-        m_SelState.Set(m_wpOldCaret, m_wpCaret);
-
       ScrollToCaret();
-      Refresh();
+      SetCaretOrigin();
       SetCaretInfo();
-    } else {
-      if (m_SelState.IsExist()) {
-        if (m_SelState.BeginPos.WordCmp(m_SelState.EndPos) < 0)
-          SetCaret(m_SelState.BeginPos);
-        else
-          SetCaret(m_SelState.EndPos);
-
-        SelectNone();
-        ScrollToCaret();
-        SetCaretInfo();
-      } else {
-        if (bCtrl)
-          SetCaret(m_pVT->GetBeginWordPlace());
-        else
-          SetCaret(m_pVT->GetLineBeginPlace(m_wpCaret));
-
-        ScrollToCaret();
-        SetCaretOrigin();
-        SetCaretInfo();
-      }
     }
   }
 }
 
 void CFX_Edit::OnVK_END(bool bShift, bool bCtrl) {
-  if (m_pVT->IsValid()) {
-    if (bShift) {
+  if (!m_pVT->IsValid())
+    return;
+
+  if (bShift) {
+    if (bCtrl)
+      SetCaret(m_pVT->GetEndWordPlace());
+    else
+      SetCaret(m_pVT->GetLineEndPlace(m_wpCaret));
+
+    if (m_SelState.IsEmpty())
+      m_SelState.Set(m_wpOldCaret, m_wpCaret);
+    else
+      m_SelState.SetEndPos(m_wpCaret);
+
+    ScrollToCaret();
+    Refresh();
+    SetCaretInfo();
+  } else {
+    if (!m_SelState.IsEmpty()) {
+      SetCaret(std::max(m_SelState.BeginPos, m_SelState.EndPos));
+      SelectNone();
+      ScrollToCaret();
+      SetCaretInfo();
+    } else {
       if (bCtrl)
         SetCaret(m_pVT->GetEndWordPlace());
       else
         SetCaret(m_pVT->GetLineEndPlace(m_wpCaret));
 
-      if (m_SelState.IsExist())
-        m_SelState.SetEndPos(m_wpCaret);
-      else
-        m_SelState.Set(m_wpOldCaret, m_wpCaret);
-
       ScrollToCaret();
-      Refresh();
+      SetCaretOrigin();
       SetCaretInfo();
-    } else {
-      if (m_SelState.IsExist()) {
-        if (m_SelState.BeginPos.WordCmp(m_SelState.EndPos) > 0)
-          SetCaret(m_SelState.BeginPos);
-        else
-          SetCaret(m_SelState.EndPos);
-
-        SelectNone();
-        ScrollToCaret();
-        SetCaretInfo();
-      } else {
-        if (bCtrl)
-          SetCaret(m_pVT->GetEndWordPlace());
-        else
-          SetCaret(m_pVT->GetLineEndPlace(m_wpCaret));
-
-        ScrollToCaret();
-        SetCaretOrigin();
-        SetCaretInfo();
-      }
     }
   }
 }
@@ -1928,7 +1899,7 @@ bool CFX_Edit::Backspace(bool bAddUndo, bool bPaint) {
     return false;
 
   if (bAddUndo && m_bEnableUndo) {
-    if (m_wpCaret.SecCmp(m_wpOldCaret) != 0) {
+    if (m_wpCaret.nSecIndex != m_wpOldCaret.nSecIndex) {
       AddEditUndoItem(pdfium::MakeUnique<CFXEU_Backspace>(
           this, m_wpOldCaret, m_wpCaret, word.Word, word.nCharset,
           section.SecProps, section.WordProps));
@@ -2003,7 +1974,7 @@ bool CFX_Edit::Empty() {
 }
 
 bool CFX_Edit::Clear(bool bAddUndo, bool bPaint) {
-  if (!m_pVT->IsValid() || !m_SelState.IsExist())
+  if (!m_pVT->IsValid() || m_SelState.IsEmpty())
     return false;
 
   CPVT_WordRange range = m_SelState.ConvertToWordRange();
@@ -2255,9 +2226,9 @@ CPVT_WordRange CFX_Edit_Select::ConvertToWordRange() const {
   return CPVT_WordRange(BeginPos, EndPos);
 }
 
-void CFX_Edit_Select::Default() {
-  BeginPos.Default();
-  EndPos.Default();
+void CFX_Edit_Select::Reset() {
+  BeginPos.Reset();
+  EndPos.Reset();
 }
 
 void CFX_Edit_Select::Set(const CPVT_WordPlace& begin,
@@ -2274,8 +2245,8 @@ void CFX_Edit_Select::SetEndPos(const CPVT_WordPlace& end) {
   EndPos = end;
 }
 
-bool CFX_Edit_Select::IsExist() const {
-  return BeginPos != EndPos;
+bool CFX_Edit_Select::IsEmpty() const {
+  return BeginPos == EndPos;
 }
 
 CFX_Edit_RectArray::CFX_Edit_RectArray() {}
diff --git a/fpdfsdk/fxedit/fxet_edit.h b/fpdfsdk/fxedit/fxet_edit.h
index 4fcb5569c3..08a13a87bd 100644
--- a/fpdfsdk/fxedit/fxet_edit.h
+++ b/fpdfsdk/fxedit/fxet_edit.h
@@ -90,13 +90,13 @@ class CFX_Edit_Select {
   CFX_Edit_Select(const CPVT_WordPlace& begin, const CPVT_WordPlace& end);
   explicit CFX_Edit_Select(const CPVT_WordRange& range);
 
-  void Default();
+  void Reset();
   void Set(const CPVT_WordPlace& begin, const CPVT_WordPlace& end);
   void SetBeginPos(const CPVT_WordPlace& begin);
   void SetEndPos(const CPVT_WordPlace& end);
 
   CPVT_WordRange ConvertToWordRange() const;
-  bool IsExist() const;
+  bool IsEmpty() const;
 
   CPVT_WordPlace BeginPos;
   CPVT_WordPlace EndPos;
diff --git a/fpdfsdk/pdfwindow/PWL_Edit.cpp b/fpdfsdk/pdfwindow/PWL_Edit.cpp
index f84c38e23b..4b9e0d2f49 100644
--- a/fpdfsdk/pdfwindow/PWL_Edit.cpp
+++ b/fpdfsdk/pdfwindow/PWL_Edit.cpp
@@ -6,6 +6,7 @@
 
 #include "fpdfsdk/pdfwindow/PWL_Edit.h"
 
+#include <algorithm>
 #include <memory>
 #include <vector>
 
@@ -791,21 +792,8 @@ void CPWL_Edit::OnInsertText(const CPVT_WordPlace& place,
 
 CPVT_WordRange CPWL_Edit::CombineWordRange(const CPVT_WordRange& wr1,
                                            const CPVT_WordRange& wr2) {
-  CPVT_WordRange wrRet;
-
-  if (wr1.BeginPos.WordCmp(wr2.BeginPos) < 0) {
-    wrRet.BeginPos = wr1.BeginPos;
-  } else {
-    wrRet.BeginPos = wr2.BeginPos;
-  }
-
-  if (wr1.EndPos.WordCmp(wr2.EndPos) < 0) {
-    wrRet.EndPos = wr2.EndPos;
-  } else {
-    wrRet.EndPos = wr1.EndPos;
-  }
-
-  return wrRet;
+  return CPVT_WordRange(std::min(wr1.BeginPos, wr2.BeginPos),
+                        std::max(wr1.EndPos, wr2.EndPos));
 }
 
 CPVT_WordRange CPWL_Edit::GetLatinWordsRange(const CFX_PointF& point) const {
diff --git a/fpdfsdk/pdfwindow/PWL_Utils.cpp b/fpdfsdk/pdfwindow/PWL_Utils.cpp
index f78b590150..08b5e3013a 100644
--- a/fpdfsdk/pdfwindow/PWL_Utils.cpp
+++ b/fpdfsdk/pdfwindow/PWL_Utils.cpp
@@ -26,28 +26,13 @@ CFX_FloatRect CPWL_Utils::OffsetRect(const CFX_FloatRect& rect,
 
 CPVT_WordRange CPWL_Utils::OverlapWordRange(const CPVT_WordRange& wr1,
                                             const CPVT_WordRange& wr2) {
-  CPVT_WordRange wrRet;
-
-  if (wr2.EndPos.WordCmp(wr1.BeginPos) < 0 ||
-      wr2.BeginPos.WordCmp(wr1.EndPos) > 0)
-    return wrRet;
-  if (wr1.EndPos.WordCmp(wr2.BeginPos) < 0 ||
-      wr1.BeginPos.WordCmp(wr2.EndPos) > 0)
-    return wrRet;
-
-  if (wr1.BeginPos.WordCmp(wr2.BeginPos) < 0) {
-    wrRet.BeginPos = wr2.BeginPos;
-  } else {
-    wrRet.BeginPos = wr1.BeginPos;
+  if (wr2.EndPos < wr1.BeginPos || wr2.BeginPos > wr1.EndPos ||
+      wr1.EndPos < wr2.BeginPos || wr1.BeginPos > wr2.EndPos) {
+    return CPVT_WordRange();
   }
 
-  if (wr1.EndPos.WordCmp(wr2.EndPos) < 0) {
-    wrRet.EndPos = wr1.EndPos;
-  } else {
-    wrRet.EndPos = wr2.EndPos;
-  }
-
-  return wrRet;
+  return CPVT_WordRange(std::max(wr1.BeginPos, wr2.BeginPos),
+                        std::min(wr1.EndPos, wr2.EndPos));
 }
 
 CFX_ByteString CPWL_Utils::GetAP_Check(const CFX_FloatRect& crBBox) {