zhjwpku commented on code in PR #238:
URL: https://github.com/apache/iceberg-cpp/pull/238#discussion_r2436582271
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src/iceberg/expression/literal.cc:
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@@ -193,12 +205,44 @@ std::strong_ordering CompareFloat(T lhs, T rhs) {
return lhs_is_negative <=> rhs_is_negative;
}
+std::strong_ordering CompareDecimal(Literal const& lhs, Literal const& rhs) {
+ ICEBERG_DCHECK(std::holds_alternative<Decimal>(lhs.value()),
+ "LHS of decimal comparison must hold Decimal");
+ ICEBERG_DCHECK(std::holds_alternative<Decimal>(rhs.value()),
+ "RHS of decimal comparison must hold decimal");
+ const auto& lhs_type = std::dynamic_pointer_cast<DecimalType>(lhs.type());
+ const auto& rhs_type = std::dynamic_pointer_cast<DecimalType>(rhs.type());
+ ICEBERG_DCHECK(lhs_type != nullptr, "LHS type must be DecimalType");
+ ICEBERG_DCHECK(rhs_type != nullptr, "RHS type must be DecimalType");
+ auto lhs_decimal = std::get<Decimal>(lhs.value());
+ auto rhs_decimal = std::get<Decimal>(rhs.value());
+ if (lhs_type->scale() == rhs_type->scale()) {
+ return lhs_decimal <=> rhs_decimal;
+ } else if (lhs_type->scale() > rhs_type->scale()) {
+ // Rescale to larger scale
+ auto rhs_res = rhs_decimal.Rescale(rhs_type->scale(), lhs_type->scale());
+ if (!rhs_res) {
+ // Rescale would cause data loss, so lhs is definitely less than rhs
+ return std::strong_ordering::less;
+ }
+ return lhs_decimal <=> rhs_res.value();
+ } else {
+ // Rescale to larger scale
+ auto lhs_res = lhs_decimal.Rescale(lhs_type->scale(), rhs_type->scale());
+ if (!lhs_res) {
+ // Rescale would cause data loss, so lhs is definitely greater than rhs
+ return std::strong_ordering::greater;
+ }
+ return lhs_res.value() <=> rhs_decimal;
+ }
+}
+
bool Literal::operator==(const Literal& other) const { return (*this <=>
other) == 0; }
// Three-way comparison operator
std::partial_ordering Literal::operator<=>(const Literal& other) const {
// If types are different, comparison is unordered
- if (*type_ != *other.type_) {
+ if (type_->type_id() != other.type_->type_id()) {
Review Comment:
I plan to look into this later in a separate PR ;)
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