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>

1 files changed, 3 insertions, 3 deletions

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;