commit f3131ebc4fbb4e6511ee14225057ab1d062ff525
author Lei Zhang <thestig@chromium.org> Thu Jan 23 20:01:29 2020 +0000
committer Chromium commit bot <commit-bot@chromium.org> Thu Jan 23 20:01:29 2020 +0000
tree 5c67d4e305bcf5fede75744e43faa9489ef71fad
parent e386b83c7d0a381ab0709598825b4077c9745c82

Simplify operations involving |CPDF_TextPage::m_CharIndex|.

- Avoid using an int to index into the vector.
- Remove checks for negative indices that cannot happen.
- Use size(), empty() and back() where appropriate.
- Make calculations in TextIndexFromCharIndex() simpler.

Change-Id: I97057a6017711dcce8afc57a8fdb08f23d405d6d
Reviewed-on: https://pdfium-review.googlesource.com/c/pdfium/+/65414
Reviewed-by: Tom Sepez <tsepez@chromium.org>
Commit-Queue: Lei Zhang <thestig@chromium.org>

core/fpdftext/cpdf_textpage.cpp

diff --git a/core/fpdftext/cpdf_textpage.cpp b/core/fpdftext/cpdf_textpage.cpp
index 4bda087..260b101 100644
--- a/core/fpdftext/cpdf_textpage.cpp
+++ b/core/fpdftext/cpdf_textpage.cpp
@@ -261,23 +261,22 @@
     m_CharIndex.push_back(0);
 
   for (int i = 0; i < nCount; ++i) {
-    int indexSize = pdfium::CollectionSize<int>(m_CharIndex);
     const PAGECHAR_INFO& charinfo = m_CharList[i];
     if (charinfo.m_Flag == FPDFTEXT_CHAR_GENERATED ||
         (charinfo.m_Unicode != 0 && !IsControlChar(charinfo)) ||
         (charinfo.m_Unicode == 0 && charinfo.m_CharCode != 0)) {
-      if (indexSize % 2) {
+      if (m_CharIndex.size() % 2) {
         m_CharIndex.push_back(1);
       } else {
-        if (indexSize <= 0)
+        if (m_CharIndex.empty())
           continue;
-        m_CharIndex[indexSize - 1] += 1;
+        m_CharIndex.back() += 1;
       }
     } else {
-      if (indexSize % 2) {
-        if (indexSize <= 0)
+      if (m_CharIndex.size() % 2) {
+        if (m_CharIndex.empty())
           continue;
-        m_CharIndex[indexSize - 1] = i + 1;
+        m_CharIndex.back() = i + 1;
       } else {
         m_CharIndex.push_back(i + 1);
       }
@@ -291,28 +290,24 @@
   return pdfium::CollectionSize<int>(m_CharList);
 }
 
-int CPDF_TextPage::CharIndexFromTextIndex(int TextIndex) const {
-  int indexSize = pdfium::CollectionSize<int>(m_CharIndex);
+int CPDF_TextPage::CharIndexFromTextIndex(int text_index) const {
   int count = 0;
-  for (int i = 0; i < indexSize; i += 2) {
+  for (size_t i = 0; i < m_CharIndex.size(); i += 2) {
     count += m_CharIndex[i + 1];
-    if (count > TextIndex)
-      return TextIndex - count + m_CharIndex[i + 1] + m_CharIndex[i];
+    if (count > text_index)
+      return text_index - count + m_CharIndex[i + 1] + m_CharIndex[i];
   }
   return -1;
 }
 
-int CPDF_TextPage::TextIndexFromCharIndex(int CharIndex) const {
-  int indexSize = pdfium::CollectionSize<int>(m_CharIndex);
+int CPDF_TextPage::TextIndexFromCharIndex(int char_index) const {
   int count = 0;
-  for (int i = 0; i < indexSize; i += 2) {
-    count += m_CharIndex[i + 1];
-    if (m_CharIndex[i + 1] + m_CharIndex[i] > CharIndex) {
-      if (CharIndex - m_CharIndex[i] < 0)
-        return -1;
+  for (size_t i = 0; i < m_CharIndex.size(); i += 2) {
+    int text_index = char_index - m_CharIndex[i];
+    if (text_index < m_CharIndex[i + 1])
+      return text_index >= 0 ? text_index + count : -1;
 
-      return CharIndex - m_CharIndex[i] + count - m_CharIndex[i + 1];
-    }
+    count += m_CharIndex[i + 1];
   }
   return -1;
 }

core/fpdftext/cpdf_textpage.h

diff --git a/core/fpdftext/cpdf_textpage.h b/core/fpdftext/cpdf_textpage.h
index b4e11d1..cd5c13d 100644
--- a/core/fpdftext/cpdf_textpage.h
+++ b/core/fpdftext/cpdf_textpage.h
@@ -82,8 +82,8 @@
   ~CPDF_TextPage();
 
   bool IsParsed() const { return m_bIsParsed; }
-  int CharIndexFromTextIndex(int TextIndex) const;
-  int TextIndexFromCharIndex(int CharIndex) const;
+  int CharIndexFromTextIndex(int text_index) const;
+  int TextIndexFromCharIndex(int char_index) const;
   size_t size() const { return m_CharList.size(); }
   int CountChars() const;
   void GetCharInfo(size_t index, CharInfo* info) const;