Add pdfium::Vector2D<>()

Many of the FX_Alloc's that have not been converted to std::vector
are using FX_Alloc2D and the safe math it performs under the covers.
Make an equivalent function for returning a vector to avoid burdening
callers with the safe math equivalents.

Use it in one place.

Change-Id: Ie4a280351b7370b755f2a1928f8b2d84fe007c03
Reviewed-on: https://pdfium-review.googlesource.com/36770
Commit-Queue: Tom Sepez <tsepez@chromium.org>
Reviewed-by: Lei Zhang <thestig@chromium.org>

1 files changed, 10 insertions, 0 deletions

diff --git a/third_party/base/stl_util.h b/third_party/base/stl_util.h
index 6c36ddcda1..5d984dc4cc 100644
--- a/third_party/base/stl_util.h
+++ b/third_party/base/stl_util.h
@@ -9,8 +9,10 @@
 #include <iterator>
 #include <memory>
 #include <set>
+#include <vector>
 
 #include "third_party/base/numerics/safe_conversions.h"
+#include "third_party/base/numerics/safe_math.h"
 
 namespace pdfium {
 
@@ -74,6 +76,14 @@ constexpr const T& clamp(const T& v, const T& lo, const T& hi) {
   return std::min(std::max(v, lo), hi);
 }
 
+// Safely allocate a 1-dim vector big enough for |w| by |h| or die.
+template <typename T>
+std::vector<T> Vector2D(size_t w, size_t h) {
+  pdfium::base::CheckedNumeric<size_t> safe_size = w;
+  safe_size *= h;
+  return std::vector<T>(safe_size.ValueOrDie());
+}
+
 }  // namespace pdfium
 
 #endif  // PDFIUM_THIRD_PARTY_BASE_STL_UTIL_H_