add other session providers (#5963)

vendor/github.com/syndtr/goleveldb/leveldb/util/hash.go

@@ -0,0 +1,48 @@
+// Copyright (c) 2012, Suryandaru Triandana <syndtr@gmail.com>
+// All rights reserved.
+//
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+package util
+
+import (
+	"encoding/binary"
+)
+
+// Hash return hash of the given data.
+func Hash(data []byte, seed uint32) uint32 {
+	// Similar to murmur hash
+	const (
+		m = uint32(0xc6a4a793)
+		r = uint32(24)
+	)
+	var (
+		h = seed ^ (uint32(len(data)) * m)
+		i int
+	)
+
+	for n := len(data) - len(data)%4; i < n; i += 4 {
+		h += binary.LittleEndian.Uint32(data[i:])
+		h *= m
+		h ^= (h >> 16)
+	}
+
+	switch len(data) - i {
+	default:
+		panic("not reached")
+	case 3:
+		h += uint32(data[i+2]) << 16
+		fallthrough
+	case 2:
+		h += uint32(data[i+1]) << 8
+		fallthrough
+	case 1:
+		h += uint32(data[i])
+		h *= m
+		h ^= (h >> r)
+	case 0:
+	}
+
+	return h
+}