From c9c6b96eede7d78758ca7ca5db98bf8b24021d0f Mon Sep 17 00:00:00 2001
From: Andrew Kane <andrew@ankane.org>
Date: Wed, 5 Oct 2022 16:11:37 -0700
Subject: [PATCH] Added support for Postgres 15 [skip ci]

---
 CHANGELOG.md    |  4 ++++
 src/ivfbuild.c  |  4 ++++
 src/ivfkmeans.c | 23 ++++++++++++++++++++---
 3 files changed, 28 insertions(+), 3 deletions(-)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index 88d4adc..2d7edb9 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,3 +1,7 @@
+## 0.3.0 (unreleased)
+
+- Added support for Postgres 15
+
 ## 0.2.7 (2022-07-31)
 
 - Fixed `unexpected data beyond EOF` error
diff --git a/src/ivfbuild.c b/src/ivfbuild.c
index 791cb0b..6875d22 100644
--- a/src/ivfbuild.c
+++ b/src/ivfbuild.c
@@ -80,7 +80,11 @@ SampleCallback(Relation index, CALLBACK_ITEM_POINTER, Datum *values,
 
 		if (buildstate->rowstoskip <= 0)
 		{
+#if PG_VERSION_NUM >= 150000
+			int			k = (int) (targsamples * sampler_random_fract(&buildstate->rstate.randstate));
+#else
 			int			k = (int) (targsamples * sampler_random_fract(buildstate->rstate.randstate));
+#endif
 
 			Assert(k >= 0 && k < targsamples);
 			VectorArraySet(samples, k, DatumGetVector(value));
diff --git a/src/ivfkmeans.c b/src/ivfkmeans.c
index 60a07f7..9b13691 100644
--- a/src/ivfkmeans.c
+++ b/src/ivfkmeans.c
@@ -5,6 +5,23 @@
 #include "ivfflat.h"
 #include "miscadmin.h"
 
+#if PG_VERSION_NUM >= 150000
+#include "common/pg_prng.h"
+#endif
+
+/*
+ * Random double
+ */
+static inline double
+RandomDouble()
+{
+#if PG_VERSION_NUM >= 150000
+	return pg_prng_double(&pg_global_prng_state);
+#else
+	return (((double) random()) / MAX_RANDOM_VALUE);
+#endif
+}
+
 /*
  * Initialize with kmeans++
  *
@@ -66,7 +83,7 @@ InitCenters(Relation index, VectorArray samples, VectorArray centers, float *low
 			break;
 
 		/* Choose new center using weighted probability distribution. */
-		choice = sum * (((double) random()) / MAX_RANDOM_VALUE);
+		choice = sum * RandomDouble();
 		for (j = 0; j < numSamples - 1; j++)
 		{
 			choice -= weight[j];
@@ -145,7 +162,7 @@ QuickCenters(Relation index, VectorArray samples, VectorArray centers)
 		vec->dim = dimensions;
 
 		for (j = 0; j < dimensions; j++)
-			vec->x[j] = ((double) random()) / MAX_RANDOM_VALUE;
+			vec->x[j] = RandomDouble();
 
 		/* Normalize if needed (only needed for random centers) */
 		if (normprocinfo != NULL)
@@ -403,7 +420,7 @@ ElkanKmeans(Relation index, VectorArray samples, VectorArray centers)
 			{
 				/* TODO Handle empty centers properly */
 				for (k = 0; k < dimensions; k++)
-					vec->x[k] = ((double) random()) / MAX_RANDOM_VALUE;
+					vec->x[k] = RandomDouble();
 			}
 
 			/* Normalize if needed */