1 files changed, 66 insertions, 0 deletions
diff --git a/go/swift-rpc-losf/swift.go b/go/swift-rpc-losf/swift.go
new file mode 100644
index 000000000..c51362dac
--- /dev/null
+++ b/go/swift-rpc-losf/swift.go
@@ -0,0 +1,66 @@
+// Copyright (c) 2010-2012 OpenStack Foundation
+//
+// 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.
+
+package main
+
+import (
+	"errors"
+	"fmt"
+	"strconv"
+)
+
+// getPartitionFromOhash returns the partition, given an object hash and the partition bit count
+func getPartitionFromOhash(ohash []byte, partitionBits int) (partition uint64, err error) {
+	if len(ohash) < 16 {
+		err = errors.New("ohash must be at least 16 bits long")
+		return
+	}
+	highHash, err := strconv.ParseUint(string(ohash[0:16]), 16, 64)
+	if err != nil {
+		return
+	}
+
+	// shift to get the partition
+	partition = highHash >> uint64(64-partitionBits)
+	return
+}
+
+// getLastPartition returns the last possible partition given the partition bit count
+func getLastPartition(partitionBits int) (partition uint64, err error) {
+	for i := 0; i < partitionBits; i++ {
+		partition |= 1 << uint64(i)
+	}
+	return
+}
+
+// Returns the first possible object prefix the KV for the given partition and bit count
+// Example: 876, 18 bits -> 00db000000000000
+func getObjPrefixFromPartition(partition uint64, partitionBits int) (prefix []byte, err error) {
+	firstnum := partition << uint64(64-partitionBits)
+	prefix = []byte(fmt.Sprintf("%016x0000000000000000", firstnum))
+	return
+}
+
+// Returns the first possible object prefix the KV for the given partition and bit count,
+// in its encoded form
+func getEncodedObjPrefixFromPartition(partition uint64, partitionBits int) (prefix []byte, err error) {
+	key, err := getObjPrefixFromPartition(partition, partitionBits)
+	if err != nil {
+		return
+	}
+
+	prefix, err = EncodeObjectKey(key)
+	return
+}