Update to last common bleve (#3986)

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

@@ -0,0 +1,92 @@
+//  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
+
+import (
+	"bufio"
+	"io"
+)
+
+// A writer is a buffered writer used by vellum. It counts how many bytes have
+// been written and has some convenience methods used for encoding the data.
+type writer struct {
+	w       *bufio.Writer
+	counter int
+}
+
+func newWriter(w io.Writer) *writer {
+	return &writer{
+		w: bufio.NewWriter(w),
+	}
+}
+
+func (w *writer) Reset(newWriter io.Writer) {
+	w.w.Reset(newWriter)
+	w.counter = 0
+}
+
+func (w *writer) WriteByte(c byte) error {
+	err := w.w.WriteByte(c)
+	if err != nil {
+		return err
+	}
+	w.counter++
+	return nil
+}
+
+func (w *writer) Write(p []byte) (int, error) {
+	n, err := w.w.Write(p)
+	w.counter += n
+	return n, err
+}
+
+func (w *writer) Flush() error {
+	return w.w.Flush()
+}
+
+func (w *writer) WritePackedUintIn(v uint64, n int) error {
+	for shift := uint(0); shift < uint(n*8); shift += 8 {
+		err := w.WriteByte(byte(v >> shift))
+		if err != nil {
+			return err
+		}
+	}
+
+	return nil
+}
+
+func (w *writer) WritePackedUint(v uint64) error {
+	n := packedSize(v)
+	return w.WritePackedUintIn(v, n)
+}
+
+func packedSize(n uint64) int {
+	if n < 1<<8 {
+		return 1
+	} else if n < 1<<16 {
+		return 2
+	} else if n < 1<<24 {
+		return 3
+	} else if n < 1<<32 {
+		return 4
+	} else if n < 1<<40 {
+		return 5
+	} else if n < 1<<48 {
+		return 6
+	} else if n < 1<<56 {
+		return 7
+	}
+	return 8
+}