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// 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
}
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