From 760162fedb4f7ee6f0167cc6acfadee6ccb6be66 Mon Sep 17 00:00:00 2001
From: Nathan Bossart
Date: Mon, 12 Aug 2024 10:35:06 -0500
Subject: Add user-callable CRC functions.

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
---
 src/backend/utils/hash/pg_crc.c | 35 ++++++++++++++++++++++++++++++++++-
 1 file changed, 34 insertions(+), 1 deletion(-)

(limited to 'src/backend/utils/hash')

diff --git a/src/backend/utils/hash/pg_crc.c b/src/backend/utils/hash/pg_crc.c
index 3595938dc4f..a85e6171864 100644
--- a/src/backend/utils/hash/pg_crc.c
+++ b/src/backend/utils/hash/pg_crc.c
@@ -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);
+}
-- 
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