Commits
Benjamin Kietzman authored and Wes McKinney committed 5fa694ba787
ARROW-1741: [C++] Add DictionaryArray::CanCompareIndices
Tests whether arrays' dictionaries are prefixes of other arrays' dictionaries, which allows them to be compared without unification since the indices refer to identical values.
Closes #5342 from bkietz/1741-Comparison-function-for-D and squashes the following commits:
960086803 <Benjamin Kietzman> iwyu: algorithm
544a7c735 <Benjamin Kietzman> iwyu: memory
08022c928 <Benjamin Kietzman> remove error status validation
0f3cbd7d8 <Benjamin Kietzman> move dictionary array specific code to array/dict_internal.{h,cc}
e85d0ae99 <Benjamin Kietzman> refactor to DictionaryArray::CanCompareIndices
2f20180d5 <Benjamin Kietzman> ARROW-1741: Add DictionaryType::ComparableWithoutUnification
Authored-by: Benjamin Kietzman <bengilgit@gmail.com>
Signed-off-by: Wes McKinney <wesm+git@apache.org>