Here is what I have staged for commit. The only differences from v1 are some very light edits.
-- nathan
>From aa0cc332c6fbadfa6f49ab072dd97c5c8d78fdf8 Mon Sep 17 00:00:00 2001 From: Nathan Bossart <nat...@postgresql.org> Date: Tue, 11 Mar 2025 11:01:32 -0500 Subject: [PATCH v2 1/1] Add reverse() for bytea. This commit introduces a function for reversing the order of the bytes in binary strings. NEEDS CATVERSION BUMP Author: Aleksander Alekseev <aleksan...@timescale.com> Discussion: https://postgr.es/m/CAJ7c6TMe0QVRuNssUArbMi0bJJK32%2BzNA3at5m3osrBQ25MHuw%40mail.gmail.com --- doc/src/sgml/func.sgml | 17 +++++++++++++++++ src/backend/utils/adt/varlena.c | 21 +++++++++++++++++++++ src/include/catalog/pg_proc.dat | 3 +++ src/test/regress/expected/strings.out | 18 ++++++++++++++++++ src/test/regress/sql/strings.sql | 4 ++++ 5 files changed, 63 insertions(+) diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml index 51dd8ad6571..1c3810e1a04 100644 --- a/doc/src/sgml/func.sgml +++ b/doc/src/sgml/func.sgml @@ -4660,6 +4660,23 @@ SELECT format('Testing %3$s, %2$s, %s', 'one', 'two', 'three'); </para></entry> </row> + <row> + <entry role="func_table_entry"><para role="func_signature"> + <indexterm> + <primary>reverse</primary> + </indexterm> + <function>reverse</function> ( <type>bytea</type> ) + <returnvalue>bytea</returnvalue> + </para> + <para> + Reverses the order of the bytes in the binary string. + </para> + <para> + <literal>reverse('\xabcd'::bytea)</literal> + <returnvalue>\xcdab</returnvalue> + </para></entry> + </row> + <row> <entry role="func_table_entry"><para role="func_signature"> <indexterm> diff --git a/src/backend/utils/adt/varlena.c b/src/backend/utils/adt/varlena.c index cdf185ea00b..95631eb2099 100644 --- a/src/backend/utils/adt/varlena.c +++ b/src/backend/utils/adt/varlena.c @@ -3398,6 +3398,27 @@ byteaSetBit(PG_FUNCTION_ARGS) PG_RETURN_BYTEA_P(res); } +/* + * Return reversed bytea + */ +Datum +bytea_reverse(PG_FUNCTION_ARGS) +{ + bytea *v = PG_GETARG_BYTEA_PP(0); + const char *p = VARDATA_ANY(v); + int len = VARSIZE_ANY_EXHDR(v); + const char *endp = p + len; + bytea *result = palloc(len + VARHDRSZ); + char *dst = (char *) VARDATA(result) + len; + + SET_VARSIZE(result, len + VARHDRSZ); + + while (p < endp) + *(--dst) = *p++; + + PG_RETURN_BYTEA_P(result); +} + /* text_name() * Converts a text type to a Name type. diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat index 42e427f8fe8..890822eaf79 100644 --- a/src/include/catalog/pg_proc.dat +++ b/src/include/catalog/pg_proc.dat @@ -1518,6 +1518,9 @@ { oid => '6163', descr => 'number of set bits', proname => 'bit_count', prorettype => 'int8', proargtypes => 'bytea', prosrc => 'bytea_bit_count' }, +{ oid => '8694', descr => 'reverse bytea', + proname => 'reverse', prorettype => 'bytea', proargtypes => 'bytea', + prosrc => 'bytea_reverse' }, { oid => '725', proname => 'dist_pl', prorettype => 'float8', proargtypes => 'point line', diff --git a/src/test/regress/expected/strings.out b/src/test/regress/expected/strings.out index f8cba9f5b24..fbe7d7be71f 100644 --- a/src/test/regress/expected/strings.out +++ b/src/test/regress/expected/strings.out @@ -236,6 +236,24 @@ SELECT E'De\\678dBeEf'::bytea; ERROR: invalid input syntax for type bytea LINE 1: SELECT E'De\\678dBeEf'::bytea; ^ +SELECT reverse(''::bytea); + reverse +--------- + \x +(1 row) + +SELECT reverse('\xaa'::bytea); + reverse +--------- + \xaa +(1 row) + +SELECT reverse('\xabcd'::bytea); + reverse +--------- + \xcdab +(1 row) + SET bytea_output TO escape; SELECT E'\\xDeAdBeEf'::bytea; bytea diff --git a/src/test/regress/sql/strings.sql b/src/test/regress/sql/strings.sql index 4deb0683d57..ed054e6e99c 100644 --- a/src/test/regress/sql/strings.sql +++ b/src/test/regress/sql/strings.sql @@ -77,6 +77,10 @@ SELECT E'De\123dBeEf'::bytea; SELECT E'De\\123dBeEf'::bytea; SELECT E'De\\678dBeEf'::bytea; +SELECT reverse(''::bytea); +SELECT reverse('\xaa'::bytea); +SELECT reverse('\xabcd'::bytea); + SET bytea_output TO escape; SELECT E'\\xDeAdBeEf'::bytea; SELECT E'\\x De Ad Be Ef '::bytea; -- 2.39.5 (Apple Git-154)
