GDALMDArray::ReadUsingContiguousIRead(): avoid (valid) unsigned integ…

…er overflow
innFactory · Oct 7, 2023 · 78d5980 · 78d5980
1 parent 2cf3921
commit 78d5980
Showing 1 changed file with 2 additions and 1 deletion.
diff --git a/gcore/gdalmultidim.cpp b/gcore/gdalmultidim.cpp
@@ -4734,7 +4734,8 @@ bool GDALMDArray::ReadUsingContiguousIRead(
         if (arrayStep[i] > 0)
             anTmpStartIdx[i] = arrayStartIdx[i];
         else
-            anTmpStartIdx[i] = arrayStartIdx[i] + (count[i] - 1) * arrayStep[i];
+            anTmpStartIdx[i] =
+                arrayStartIdx[i] - (count[i] - 1) * (-arrayStep[i]);
         const uint64_t nCount =
             (count[i] - 1) * static_cast<uint64_t>(std::abs(arrayStep[i])) + 1;
         if (nCount > std::numeric_limits<size_t>::max() / nMemArraySize)