Update to last common bleve (#3986)

vendor/github.com/couchbase/vellum/pack.go

@@ -0,0 +1,55 @@
+//  Copyright (c) 2017 Couchbase, 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.
+
+package vellum
+
+func deltaAddr(base, trans uint64) uint64 {
+	// transition dest of 0 is special case
+	if trans == 0 {
+		return 0
+	}
+	return base - trans
+}
+
+const packOutMask = 1<<4 - 1
+
+func encodePackSize(transSize, outSize int) byte {
+	var rv byte
+	rv = byte(transSize << 4)
+	rv |= byte(outSize)
+	return rv
+}
+
+func decodePackSize(pack byte) (transSize int, packSize int) {
+	transSize = int(pack >> 4)
+	packSize = int(pack & packOutMask)
+	return
+}
+
+const maxNumTrans = 1<<6 - 1
+
+func encodeNumTrans(n int) byte {
+	if n <= maxNumTrans {
+		return byte(n)
+	}
+	return 0
+}
+
+func readPackedUint(data []byte) (rv uint64) {
+	for i := range data {
+		shifted := uint64(data[i]) << uint(i*8)
+		rv |= shifted
+	}
+	return
+}