commit b588d237d6c0bd27520647ab660df59e695a468b
author Tom Sepez <tsepez@chromium.org> Fri Aug 26 21:38:42 2022 +0000
committer Pdfium LUCI CQ <pdfium-scoped@luci-project-accounts.iam.gserviceaccount.com> Fri Aug 26 21:38:42 2022 +0000
tree 21bb97f51bad72c382569f31c0bdf9801cd8ffa0
parent 6c759cd2fdacb2a7c5f44717c425802a5b6821af

Avoid pointer arithmetic in cfx_datetime.cpp

Convert to spans, which will hard check on OOB.

-- remove soft checks given the above.

Change-Id: I2c8f540b89e09f0e0121da264a3a747dff34de0f
Reviewed-on: https://pdfium-review.googlesource.com/c/pdfium/+/96951
Commit-Queue: Tom Sepez <tsepez@chromium.org>
Reviewed-by: Lei Zhang <thestig@chromium.org>
Auto-Submit: Tom Sepez <tsepez@chromium.org>

core/fxcrt/cfx_datetime.cpp

diff --git a/core/fxcrt/cfx_datetime.cpp b/core/fxcrt/cfx_datetime.cpp
index 731b56a..90cb377 100644
--- a/core/fxcrt/cfx_datetime.cpp
+++ b/core/fxcrt/cfx_datetime.cpp
@@ -10,6 +10,7 @@
 #include "core/fxcrt/fx_extension.h"
 #include "core/fxcrt/fx_system.h"
 #include "third_party/base/check.h"
+#include "third_party/base/span.h"
 
 namespace {
 
@@ -26,11 +27,10 @@
 
 int32_t DaysBeforeMonthInYear(int32_t iYear, uint8_t iMonth) {
   DCHECK(iYear != 0);
-  DCHECK(iMonth >= 1);
-  DCHECK(iMonth <= 12);
-
-  const int32_t* p =
-      FX_IsLeapYear(iYear) ? kDaysBeforeLeapMonth : kDaysBeforeMonth;
+  pdfium::span<const int32_t> p = FX_IsLeapYear(iYear)
+                                      ? pdfium::make_span(kDaysBeforeLeapMonth)
+                                      : pdfium::make_span(kDaysBeforeMonth);
+  // Note: iMonth is one-based.
   return p[iMonth - 1];
 }
 
@@ -68,10 +68,10 @@
 
 uint8_t FX_DaysInMonth(int32_t iYear, uint8_t iMonth) {
   DCHECK(iYear != 0);
-  DCHECK(iMonth >= 1);
-  DCHECK(iMonth <= 12);
-
-  const uint8_t* p = FX_IsLeapYear(iYear) ? kDaysPerLeapMonth : kDaysPerMonth;
+  pdfium::span<const uint8_t> p = FX_IsLeapYear(iYear)
+                                      ? pdfium::make_span(kDaysPerLeapMonth)
+                                      : pdfium::make_span(kDaysPerMonth);
+  // Note: iMonth is one-based.
   return p[iMonth - 1];
 }