4 files changed, 27 insertions, 43 deletions

diff --git a/core/fpdftext/cpdf_linkextract.cpp b/core/fpdftext/cpdf_linkextract.cpp
index 3a38343721..05cbdfb3a7 100644
--- a/core/fpdftext/cpdf_linkextract.cpp
+++ b/core/fpdftext/cpdf_linkextract.cpp
@@ -114,7 +114,7 @@ void CPDF_LinkExtract::ExtractLinks() {
   if (!m_pTextPage->IsParsed())
     return;
 
-  m_strPageText = m_pTextPage->GetPageText(0, -1);
+  m_strPageText = m_pTextPage->GetAllPageText();
   if (m_strPageText.IsEmpty())
     return;
 
diff --git a/core/fpdftext/cpdf_textpage.cpp b/core/fpdftext/cpdf_textpage.cpp
index 7ea2061c26..8ef5522bae 100644
--- a/core/fpdftext/cpdf_textpage.cpp
+++ b/core/fpdftext/cpdf_textpage.cpp
@@ -436,49 +436,27 @@ void CPDF_TextPage::CheckMarkedContentObject(int32_t& start,
   }
 }
 
-WideString CPDF_TextPage::GetPageText(int start, int nCount) const {
-  if (!m_bIsParsed || nCount == 0)
+WideString CPDF_TextPage::GetPageText(int start, int count) const {
+  if (start < 0 || start >= CountChars() || count <= 0 || !m_bIsParsed ||
+      m_CharList.empty() || m_TextBuf.GetLength() == 0) {
     return L"";
-
-  if (start < 0)
-    start = 0;
-
-  if (nCount == -1) {
-    nCount = pdfium::CollectionSize<int>(m_CharList) - start;
-    WideStringView wsTextBuf = m_TextBuf.AsStringView();
-    return WideString(wsTextBuf.Right(wsTextBuf.GetLength() - start));
   }
-  if (nCount <= 0 || m_CharList.empty())
-    return L"";
-  if (nCount + start > pdfium::CollectionSize<int>(m_CharList) - 1)
-    nCount = pdfium::CollectionSize<int>(m_CharList) - start;
-  if (nCount <= 0)
+
+  int text_start = TextIndexFromCharIndex(start);
+  if (text_start < 0)
     return L"";
-  CheckMarkedContentObject(start, nCount);
-  int startindex = 0;
-  PAGECHAR_INFO charinfo = m_CharList[start];
-  int startOffset = 0;
-  while (charinfo.m_Index == -1) {
-    startOffset++;
-    if (startOffset > nCount ||
-        start + startOffset >= pdfium::CollectionSize<int>(m_CharList)) {
-      return L"";
-    }
-    charinfo = m_CharList[start + startOffset];
-  }
-  startindex = charinfo.m_Index;
-  charinfo = m_CharList[start + nCount - 1];
-  int nCountOffset = 0;
-  while (charinfo.m_Index == -1) {
-    nCountOffset++;
-    if (nCountOffset >= nCount)
-      return L"";
-    charinfo = m_CharList[start + nCount - nCountOffset - 1];
-  }
-  nCount = start + nCount - nCountOffset - startindex;
-  if (nCount <= 0)
+
+  count = std::min(count, CountChars() - start);
+
+  int last = start + count - 1;
+  int text_last = TextIndexFromCharIndex(last);
+  if (text_last < 0 || text_last < text_start)
     return L"";
-  return WideString(m_TextBuf.AsStringView().Mid(startindex, nCount));
+
+  int text_count = text_last - text_start + 1;
+
+  return WideString(m_TextBuf.AsStringView().Mid(
+      static_cast<size_t>(text_start), static_cast<size_t>(text_count)));
 }
 
 int CPDF_TextPage::CountRects(int start, int nCount) {
diff --git a/core/fpdftext/cpdf_textpage.h b/core/fpdftext/cpdf_textpage.h
index e8ab82ac2c..cd30ace3ad 100644
--- a/core/fpdftext/cpdf_textpage.h
+++ b/core/fpdftext/cpdf_textpage.h
@@ -103,7 +103,13 @@ class CPDF_TextPage {
   std::vector<CFX_FloatRect> GetRectArray(int start, int nCount) const;
   int GetIndexAtPos(const CFX_PointF& point, const CFX_SizeF& tolerance) const;
   WideString GetTextByRect(const CFX_FloatRect& rect) const;
-  WideString GetPageText(int start = 0, int nCount = -1) const;
+
+  // Returns string with the text from |m_TextBuf| that are covered by the input
+  // range. |start| and |count| are in terms of the m_CharIndex, so the range
+  // will be converted into appropriate indices.
+  WideString GetPageText(int start, int count) const;
+  WideString GetAllPageText() const { return GetPageText(0, CountChars()); }
+
   int CountRects(int start, int nCount);
   void GetRect(int rectIndex,
                float& left,
diff --git a/core/fpdftext/cpdf_textpagefind.cpp b/core/fpdftext/cpdf_textpagefind.cpp
index a874521326..9f243a0aee 100644
--- a/core/fpdftext/cpdf_textpagefind.cpp
+++ b/core/fpdftext/cpdf_textpagefind.cpp
@@ -41,7 +41,7 @@ CPDF_TextPageFind::CPDF_TextPageFind(const CPDF_TextPage* pTextPage)
       m_resStart(0),
       m_resEnd(-1),
       m_IsFind(false) {
-  m_strText = m_pTextPage->GetPageText();
+  m_strText = m_pTextPage->GetAllPageText();
   int nCount = pTextPage->CountChars();
   if (nCount)
     m_CharIndex.push_back(0);
@@ -85,7 +85,7 @@ bool CPDF_TextPageFind::FindFirst(const WideString& findwhat,
   if (!m_pTextPage)
     return false;
   if (m_strText.IsEmpty() || m_bMatchCase != (flags & FPDFTEXT_MATCHCASE))
-    m_strText = m_pTextPage->GetPageText();
+    m_strText = m_pTextPage->GetAllPageText();
   WideString findwhatStr = findwhat;
   m_findWhat = findwhatStr;
   m_flags = flags;