dmitry-chirkov-dremio commented on code in PR #52451:
URL: https://github.com/apache/arrow/pull/52451#discussion_r4334113162
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cpp/src/arrow/compute/kernels/scalar_string_ascii.cc:
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@@ -2642,7 +2642,11 @@ struct SliceBytesTransform : StringSliceTransformBase {
// on the resulting slice lengths, so return a worst case estimate.
return input_bytes;
}
- int64_t max_slice_bytes = (opt.stop - opt.start + opt.step - 1) / opt.step;
+ // SliceOptions uses INT64_MIN/MAX for open-ended bounds. Clamp both bounds
+ // before arithmetic so equivalent out-of-range indices cannot overflow
the size estimate.
+ const int64_t start = std::clamp(opt.start, -input_bytes, input_bytes);
+ const int64_t stop = std::clamp(opt.stop, -input_bytes, input_bytes);
+ int64_t max_slice_bytes = (stop - start + opt.step - 1) / opt.step;
Review Comment:
Check: input "abc", start=1, the default stop, and step=INT64_MAX
The code around here is short, but the arithmetic is fragile. See if you can
separate out boundary checks although this might as well be "one last boundary
to enforce"...
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