dhruv9vats commented on a change in pull request #12162:
URL: https://github.com/apache/arrow/pull/12162#discussion_r791685056
##########
File path: cpp/src/arrow/compute/kernels/scalar_nested.cc
##########
@@ -429,6 +429,169 @@ const FunctionDoc make_struct_doc{"Wrap Arrays into a
StructArray",
{"*args"},
"MakeStructOptions"};
+struct MapArrayLookupFunctor {
+ static Result<int64_t> FindOneMapValueIndex(const Array& keys, const Scalar&
query_key,
+ const int64_t start, const
int64_t end,
+ const bool from_back = false) {
+ if (!from_back) {
+ for (int64_t idx = start; idx < end; ++idx) {
+ ARROW_ASSIGN_OR_RAISE(std::shared_ptr<Scalar> key,
keys.GetScalar(idx));
+
+ if (key->Equals(query_key)) return idx;
+ }
+ } else {
+ for (int64_t idx = end - 1; idx >= start; --idx) {
+ ARROW_ASSIGN_OR_RAISE(std::shared_ptr<Scalar> key,
keys.GetScalar(idx));
+
+ if (key->Equals(query_key)) return idx;
+ }
+ }
+ return -1;
+ }
+
+ static Result<std::shared_ptr<Scalar>> GetScalarOutput(KernelContext* ctx,
+ const MapScalar
map_scalar) {
Review comment:
- So, this was the basic structure I was thinking of,
```cpp
template <typename KeyType>
struct MapArrayLookupFunctor {
.
.
.
const KeyType query_key = UnboxScalar<KeyType>::Unbox(*options.query_key);
...
const std::shared_ptr<Array> keys = struct_array.field(0);
...
VisitArrayValuesInline<KeyType>(
*keys->data(),
[&](KeyType key) -> Status {
if (key == query_key) {
if (occurrence == FIRST) {
...
return Status::Cancelled("Found key");
} else /*occurrence == ALL*/ {
...
return Status::OK();
}
} else { return Status::OK(); }
},
[&]() -> Status {
...
return Status::OK();
}
);
```
- But as the values are visited _inline_, how would we deal with the `LAST`
option (iterating from the back)?
- And just so I'm clear, when you say templating the kernel, you mean
templating for the `KeyType`, right?
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