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Add user-callable CRC functions.

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We've had code for CRC-32 and CRC-32C for some time (for WAL
records, etc.), but there was no way for users to call it, despite
apparent popular demand.  The new crc32() and crc32c() functions
accept bytea input and return bigint (to avoid returning negative
values).

Bumps catversion.

Author: Aleksander Alekseev
Reviewed-by: Peter Eisentraut, Tom Lane
Discussion: https://postgr.es/m/CAJ7c6TNMTGnqnG%3DyXXUQh9E88JDckmR45H2Q%2B%3DucaCLMOW1QQw%40mail.gmail.com
This commit is contained in:
Nathan Bossart
2024-08-12 10:35:06 -05:00
parent 313df8f5ad
commit 760162fedb
7 changed files with 115 additions and 2 deletions
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35
src/backend/utils/hash/pg_crc.c
View File

@@ -17,9 +17,12 @@
*-------------------------------------------------------------------------
*/
#include "c.h"
#include "postgres.h"
#include "port/pg_crc32c.h"
#include "utils/builtins.h"
#include "utils/pg_crc.h"
#include "varatt.h"
/*
* Lookup table for calculating CRC-32 using Sarwate's algorithm.
@@ -95,3 +98,33 @@ const uint32 pg_crc32_table[256] = {
0xB3667A2E, 0xC4614AB8, 0x5D681B02, 0x2A6F2B94,
0xB40BBE37, 0xC30C8EA1, 0x5A05DF1B, 0x2D02EF8D
};
/*
* SQL-callable functions
*/
Datum
crc32_bytea(PG_FUNCTION_ARGS)
{
bytea *in = PG_GETARG_BYTEA_PP(0);
pg_crc32 crc;
INIT_TRADITIONAL_CRC32(crc);
COMP_TRADITIONAL_CRC32(crc, VARDATA_ANY(in), VARSIZE_ANY_EXHDR(in));
FIN_TRADITIONAL_CRC32(crc);
PG_RETURN_INT64(crc);
}
Datum
crc32c_bytea(PG_FUNCTION_ARGS)
{
bytea *in = PG_GETARG_BYTEA_PP(0);
pg_crc32c crc;
INIT_CRC32C(crc);
COMP_CRC32C(crc, VARDATA_ANY(in), VARSIZE_ANY_EXHDR(in));
FIN_CRC32C(crc);
PG_RETURN_INT64(crc);
}