Use math/rand/v2.Uint32N instead of runtime.fastrand in v1.22

Author: Aoang

bits.go

@@ -53,6 +53,3 @@ func hasZeroByte(x uint64) bitset {
 func castUint64(m *metadata) uint64 {
 	return *(*uint64)((unsafe.Pointer)(m))
 }
-
-//go:linkname fastrand runtime.fastrand
-func fastrand() uint32

bits_amd64.go

@@ -45,6 +45,3 @@ func nextMatch(b *bitset) (s uint32) {
 	*b &= ^(1 << s) // clear bit |s|
 	return
 }
-
-//go:linkname fastrand runtime.fastrand
-func fastrand() uint32

fastrand.go

@@ -0,0 +1,29 @@
+// Copyright 2023 Dolthub, Inc.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+//go:build !go1.22
+
+package swiss
+
+import (
+	_ "unsafe"
+)
+
+//go:linkname fastrand runtime.fastrand
+func fastrand() uint32
+
+// randIntN returns a random number in the interval [0, n).
+func randIntN(n int) uint32 {
+	return fastModN(fastrand(), uint32(n))
+}

fastrand_1.22.go

@@ -0,0 +1,26 @@
+// Copyright 2023 Dolthub, Inc.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+//go:build go1.22
+
+package swiss
+
+import (
+	"math/rand/v2"
+)
+
+// randIntN returns a random number in the interval [0, n).
+func randIntN(n int) uint32 {
+	return rand.Uint32N(uint32(n))
+}

map.go

@@ -352,8 +352,3 @@ func probeStart(hi h1, groups int) uint32 {
 func fastModN(x, n uint32) uint32 {
 	return uint32((uint64(x) * uint64(n)) >> 32)
 }
-
-// randIntN returns a random number in the interval [0, n).
-func randIntN(n int) uint32 {
-	return fastModN(fastrand(), uint32(n))
-}