[C++] Faster ascii_lower and ascii_upper

[asfimport]

The current version is using a lookup table for doing the case conversion. Using http://quick-bench.com/JaDErmVCY23Z1tu6YZns_KBt0qU it seems using a boolean check and +/-32 seems ~5x times faster (4.6x for clang 9, 6.4x for GCC  9.2).

 

Reporter: Maarten Breddels / @maartenbreddels
Assignee: Maarten Breddels / @maartenbreddels

Related issues:

• [C++] String algorithm library for StringArray/BinaryArray (is related to)

PRs and other links:

• GitHub Pull Request #7434

_{Note: This issue was originally created as ARROW-9131. Please see the migration documentation for further details.}

[asfimport]

Antoine Pitrou / @pitrou:
Issue resolved by pull request 7434
#7434