Prevent reciprocal calculation for units with a constant denominator

unicode-org · Jan 20, 2025 · 9b2bce2 · 9b2bce2
1 parent 0cda889
commit 9b2bce2
Showing 1 changed file with 5 additions and 0 deletions.
diff --git a/icu4c/source/i18n/measunit_extra.cpp b/icu4c/source/i18n/measunit_extra.cpp
@@ -1488,6 +1488,11 @@ MeasureUnit MeasureUnit::withDimensionality(int32_t dimensionality, UErrorCode&
 
 MeasureUnit MeasureUnit::reciprocal(UErrorCode& status) const {
     MeasureUnitImpl impl = MeasureUnitImpl::forMeasureUnitMaybeCopy(*this, status);
+    // The reciprocal of a unit that has a constant denominator is not allowed.
+    if (impl.constantDenominator != 0) {
+        status = U_ILLEGAL_ARGUMENT_ERROR;
+        return {};
+    }
     impl.takeReciprocal(status);
     return std::move(impl).build(status);
 }