Add IndexInBounds() convenience routine.

Avoid writing |Type| in CollectionSize<Type>() so that index
type can change without rewriting conditions.

Change-Id: I40c94ca39148b379908760ba9b861114b88af7bb
Reviewed-on: https://pdfium-review.googlesource.com/3056
Reviewed-by: Lei Zhang <thestig@chromium.org>
Commit-Queue: Tom Sepez <tsepez@chromium.org>

7 files changed, 17 insertions, 28 deletions

diff --git a/core/fpdfapi/font/cpdf_font.cpp b/core/fpdfapi/font/cpdf_font.cpp
index 7988ec7124..f0b5ac16b7 100644
--- a/core/fpdfapi/font/cpdf_font.cpp
+++ b/core/fpdfapi/font/cpdf_font.cpp
@@ -458,10 +458,9 @@ uint32_t CPDF_Font::FallbackFontFromCharcode(uint32_t charcode) {
 }
 
 int CPDF_Font::FallbackGlyphFromCharcode(int fallbackFont, uint32_t charcode) {
-  if (fallbackFont < 0 ||
-      fallbackFont >= pdfium::CollectionSize<int>(m_FontFallbacks)) {
+  if (!pdfium::IndexInBounds(m_FontFallbacks, fallbackFont))
     return -1;
-  }
+
   int glyph =
       FXFT_Get_Char_Index(m_FontFallbacks[fallbackFont]->GetFace(), charcode);
   if (glyph == 0 || glyph == 0xffff)
diff --git a/core/fpdfapi/font/ttgsubtable.cpp b/core/fpdfapi/font/ttgsubtable.cpp
index 946ccd7abe..4fae5d41d2 100644
--- a/core/fpdfapi/font/ttgsubtable.cpp
+++ b/core/fpdfapi/font/ttgsubtable.cpp
@@ -127,9 +127,8 @@ bool CFX_CTTGSUBTable::GetVerticalGlyphSub(uint32_t glyphnum,
                                            uint32_t* vglyphnum,
                                            TFeature* Feature) {
   for (int index : Feature->LookupListIndices) {
-    if (index < 0 || index >= pdfium::CollectionSize<int>(LookupList.Lookups))
+    if (!pdfium::IndexInBounds(LookupList.Lookups, index))
       continue;
-
     if (LookupList.Lookups[index].LookupType == 1 &&
         GetVerticalGlyphSub2(glyphnum, vglyphnum, &LookupList.Lookups[index])) {
       return true;
@@ -154,8 +153,7 @@ bool CFX_CTTGSUBTable::GetVerticalGlyphSub2(uint32_t glyphnum,
       case 2: {
         auto* tbl2 = static_cast<TSingleSubstFormat2*>(subTable.get());
         int index = GetCoverageIndex(tbl2->Coverage.get(), glyphnum);
-        if (index >= 0 &&
-            index < pdfium::CollectionSize<int>(tbl2->Substitutes)) {
+        if (pdfium::IndexInBounds(tbl2->Substitutes, index)) {
           *vglyphnum = tbl2->Substitutes[index];
           return true;
         }
diff --git a/core/fpdfapi/page/cpdf_pageobjectlist.cpp b/core/fpdfapi/page/cpdf_pageobjectlist.cpp
index 02b590e413..5c30fe9877 100644
--- a/core/fpdfapi/page/cpdf_pageobjectlist.cpp
+++ b/core/fpdfapi/page/cpdf_pageobjectlist.cpp
@@ -10,7 +10,5 @@
 #include "third_party/base/stl_util.h"
 
 CPDF_PageObject* CPDF_PageObjectList::GetPageObjectByIndex(int index) {
-  if (index < 0 || index >= pdfium::CollectionSize<int>(*this))
-    return nullptr;
-  return (*this)[index].get();
+  return pdfium::IndexInBounds(*this, index) ? (*this)[index].get() : nullptr;
 }
diff --git a/core/fpdfapi/parser/cpdf_document.cpp b/core/fpdfapi/parser/cpdf_document.cpp
index ed88a4f82a..8ff9e66506 100644
--- a/core/fpdfapi/parser/cpdf_document.cpp
+++ b/core/fpdfapi/parser/cpdf_document.cpp
@@ -477,10 +477,10 @@ bool CPDF_Document::IsPageLoaded(int iPage) const {
 }
 
 CPDF_Dictionary* CPDF_Document::GetPage(int iPage) {
-  if (iPage < 0 || iPage >= pdfium::CollectionSize<int>(m_PageList))
+  if (!pdfium::IndexInBounds(m_PageList, iPage))
     return nullptr;
 
-  if (m_bLinearized && (iPage == m_iFirstPageNo)) {
+  if (m_bLinearized && iPage == m_iFirstPageNo) {
     if (CPDF_Dictionary* pDict =
             ToDictionary(GetOrParseIndirectObject(m_dwFirstPageObjNum))) {
       return pDict;
@@ -586,7 +586,7 @@ int CPDF_Document::GetPageIndex(uint32_t objnum) {
   int found_index = FindPageIndex(pPages, &skip_count, objnum, &start_index);
 
   // Corrupt page tree may yield out-of-range results.
-  if (found_index < 0 || found_index >= pdfium::CollectionSize<int>(m_PageList))
+  if (!pdfium::IndexInBounds(m_PageList, found_index))
     return -1;
 
   m_PageList[found_index] = objnum;
diff --git a/core/fpdftext/cpdf_textpage.cpp b/core/fpdftext/cpdf_textpage.cpp
index 7a89b24171..1eab19f4f1 100644
--- a/core/fpdftext/cpdf_textpage.cpp
+++ b/core/fpdftext/cpdf_textpage.cpp
@@ -378,10 +378,7 @@ CFX_WideString CPDF_TextPage::GetTextByRect(const CFX_FloatRect& rect) const {
 }
 
 void CPDF_TextPage::GetCharInfo(int index, FPDF_CHAR_INFO* info) const {
-  if (!m_bIsParsed)
-    return;
-
-  if (index < 0 || index >= pdfium::CollectionSize<int>(m_CharList))
+  if (!m_bIsParsed || !pdfium::IndexInBounds(m_CharList, index))
     return;
 
   const PAGECHAR_INFO& charinfo = m_CharList[index];
@@ -496,10 +493,7 @@ void CPDF_TextPage::GetRect(int rectIndex,
                             float& top,
                             float& right,
                             float& bottom) const {
-  if (!m_bIsParsed)
-    return;
-
-  if (rectIndex < 0 || rectIndex >= pdfium::CollectionSize<int>(m_SelRects))
+  if (!m_bIsParsed || !pdfium::IndexInBounds(m_SelRects, rectIndex))
     return;
 
   left = m_SelRects[rectIndex].left;
diff --git a/core/fxcodec/lgif/fx_gif.cpp b/core/fxcodec/lgif/fx_gif.cpp
index c4661b0acd..c109b6193d 100644
--- a/core/fxcodec/lgif/fx_gif.cpp
+++ b/core/fxcodec/lgif/fx_gif.cpp
@@ -841,11 +841,11 @@ int32_t gif_decode_image_info(gif_decompress_struct_p gif_ptr) {
   gif_save_decoding_status(gif_ptr, GIF_D_STATUS_IMG_DATA);
   return 1;
 }
+
 int32_t gif_load_frame(gif_decompress_struct_p gif_ptr, int32_t frame_num) {
-  if (!gif_ptr || frame_num < 0 ||
-      frame_num >= pdfium::CollectionSize<int>(*gif_ptr->img_ptr_arr_ptr)) {
+  if (!gif_ptr || !pdfium::IndexInBounds(*gif_ptr->img_ptr_arr_ptr, frame_num))
     return 0;
-  }
+
   uint8_t* data_size_ptr = nullptr;
   uint8_t* data_ptr = nullptr;
   uint32_t skip_size_org = gif_ptr->skip_size;
diff --git a/core/fxcrt/fx_arabic.cpp b/core/fxcrt/fx_arabic.cpp
index 103271cd02..76f2e38663 100644
--- a/core/fxcrt/fx_arabic.cpp
+++ b/core/fxcrt/fx_arabic.cpp
@@ -415,9 +415,9 @@ class CFX_BidiLineTemplate {
   void FX_BidiReverseString(std::vector<CFX_Char>& chars,
                             int32_t iStart,
                             int32_t iCount) {
-    ASSERT(iStart >= 0 && iStart < pdfium::CollectionSize<int32_t>(chars));
-    ASSERT(iCount >= 0 &&
-           iStart + iCount <= pdfium::CollectionSize<int32_t>(chars));
+    ASSERT(pdfium::IndexInBounds(chars, iStart));
+    ASSERT(pdfium::IndexInBounds(chars, iCount));
+    ASSERT(iStart + iCount <= pdfium::CollectionSize<int32_t>(chars));
     std::reverse(chars.begin() + iStart, chars.begin() + iStart + iCount);
   }
 
@@ -426,7 +426,7 @@ class CFX_BidiLineTemplate {
                              int32_t iStart,
                              int32_t iCount,
                              int32_t iValue) {
-    ASSERT(iStart >= 0 && iStart <= pdfium::CollectionSize<int32_t>(chars));
+    ASSERT(pdfium::IndexInBounds(chars, iStart));
     ASSERT(iStart - iCount > -1);
     int32_t iLast = iStart - iCount;
     if (bClass) {