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Re: [POC] verifying UTF-8 using SIMD instructions

Heikki Linnakangas <hlinnaka@iki.fi>

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From: Heikki Linnakangas <hlinnaka@iki.fi>
To: John Naylor <john.naylor@enterprisedb.com>
Cc: pgsql-hackers <pgsql-hackers@postgresql.org>
Date: 2021-02-09T20:22:02Z
Lists: pgsql-hackers 
On 09/02/2021 22:08, John Naylor wrote:
> Maybe there's a smarter way to check for zeros in C. Or maybe be more 
> careful about cache -- running memchr() on the whole input first might 
> not be the best thing to do.

The usual trick is the haszero() macro here: 
https://graphics.stanford.edu/~seander/bithacks.html#ZeroInWord. That's 
how memchr() is typically implemented, too.

- Heikki

Commits

Same data as JSON: GET /api/v1/messages/:b64id/commits the thread's linked commits as JSON, with link sources. API reference →

  1. Simplify coding style of is_valid_ascii()

  2. Apply auto-vectorization to the inner loop of numeric multiplication.