[GitHub] [arrow] mrkn commented on a change in pull request #9395: ARROW-11470: [C++] Detect overflow on computation of tensor strides

[GitBox <gi...@apache.org>]

mrkn commented on a change in pull request #9395:
URL: https://github.com/apache/arrow/pull/9395#discussion_r569854746



##########
File path: cpp/src/arrow/tensor.cc
##########
@@ -127,14 +163,25 @@ Status CheckTensorStridesValidity(const std::shared_ptr<Buffer>& data,
     return Status::OK();
   }
 
-  std::vector<int64_t> last_index(shape);
-  const int64_t n = static_cast<int64_t>(shape.size());
-  for (int64_t i = 0; i < n; ++i) {
-    --last_index[i];
+  // Check the largest offset can be computed without overflow
+  const auto ndim = shape.size();
+  int64_t largest_offset = 0;
+  for (auto i = decltype(ndim){0}; i < ndim; ++i) {
+    if (strides[i] <= 0) continue;

Review comment:
       Oops. I should check `dim_offset < 0` after `MultiplyWithOverflow` instead of `strides` here. I'll fix it.




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