From: Tom Lane <tgl@sss.pgh.pa.us>
To: pgsql-committers@lists.postgresql.org
Subject: pgsql: Restructure formatting.c's NUM_processor() to add some const-san
Date: Thu, 20 Aug 2026 17:01:34 +0000
Message-ID: <E1wx68z-00000001NzQ-3Ezi@gemulon.postgresql.org> (raw)
Restructure formatting.c's NUM_processor() to add some const-sanity.
NUM_processor() is an under-documented mess. Depending on the value
of is_to_char, it either reads "inout" and writes "number", or
the other way around. That makes it impossible to label either
string "const", which seems like a minimum expectation in 2026.
It also complicates replacing the output buffer with a StringInfo:
we'd have to convert both strings, which is pretty pointless for
the input side.
Moreover, we're buying very little code savings by doing it like this,
since a large majority of the function's code has to be wrapped inside
"if (is_to_char)" tests.
To fix, split the function into NUM_processor_from_char() and
NUM_processor_to_char(), and rename/const-ify arguments as
appropriate. Both paths now read from "const char *input"
and write to "char *output".
This patch doesn't intend to make any algorithmic changes, it's
just mechanical code rearrangement and symbol renaming. The
only real exception is that I got rid of passing "input_len"
to NUM_processor_from_char()'s subroutines in favor of storing
"const char *input_end" in NUMProc.
Author: Tom Lane <tgl@sss.pgh.pa.us>
Reviewed-by: Heikki Linnakangas <hlinnaka@iki.fi>
Discussion: https://postgr.es/m/3451175.1786641871@sss.pgh.pa.us
Branch
------
master
Details
-------
https://git.postgresql.org/pg/commitdiff/28c5d0724875591ff55dd85a065207badc2fa8ad
Modified Files
--------------
src/backend/utils/adt/formatting.c | 933 +++++++++++++++++++++----------------
1 file changed, 521 insertions(+), 412 deletions(-)
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To: pgsql-committers@postgresql.org
Cc: tgl@sss.pgh.pa.us, pgsql-committers@lists.postgresql.org
Subject: Re: pgsql: Restructure formatting.c's NUM_processor() to add some const-san
In-Reply-To: <E1wx68z-00000001NzQ-3Ezi@gemulon.postgresql.org>
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