[C++] Primitive concrete arrays could expose a span converter

[pitrou]

Describe the enhancement requested

Just like we have PrimitiveArray::raw_values, we could also have something that returns a arrow::util::span for easier consumption:

  const util::span<value_type> values_span() const {
    return util::span(raw_values(), static_cast<size_t>(length_));
  }

Component(s)

C++

[pitrou]

@bkietz @felipecrv

[mapleFU]

@jsjtxietian would you like to add this?

[jsjtxietian]

Will do.

[chrisjordansquire]

@jsjtxietian - Was this done / is this task still open?

[jsjtxietian]

@chrisjordansquire Hi this task is still open. I went to one month vacation rightly after I took the task. I will do this likely before October.

[felipecrv]

What about null values?

[pitrou]

They would not be exposed here. The semantics would be similar to raw_values(). Perhaps there's a use case, perhaps not...