92 lines
1.9 KiB
Go
92 lines
1.9 KiB
Go
// Copyright (c) 2017 Couchbase, Inc.
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//
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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package vellum
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import (
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"bufio"
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"io"
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)
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// A writer is a buffered writer used by vellum. It counts how many bytes have
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// been written and has some convenience methods used for encoding the data.
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type writer struct {
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w *bufio.Writer
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counter int
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}
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func newWriter(w io.Writer) *writer {
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return &writer{
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w: bufio.NewWriter(w),
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}
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}
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func (w *writer) Reset(newWriter io.Writer) {
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w.w.Reset(newWriter)
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w.counter = 0
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}
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func (w *writer) WriteByte(c byte) error {
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err := w.w.WriteByte(c)
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if err != nil {
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return err
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}
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w.counter++
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return nil
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}
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func (w *writer) Write(p []byte) (int, error) {
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n, err := w.w.Write(p)
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w.counter += n
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return n, err
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}
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func (w *writer) Flush() error {
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return w.w.Flush()
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}
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func (w *writer) WritePackedUintIn(v uint64, n int) error {
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for shift := uint(0); shift < uint(n*8); shift += 8 {
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err := w.WriteByte(byte(v >> shift))
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if err != nil {
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return err
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}
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}
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return nil
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}
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func (w *writer) WritePackedUint(v uint64) error {
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n := packedSize(v)
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return w.WritePackedUintIn(v, n)
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}
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func packedSize(n uint64) int {
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if n < 1<<8 {
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return 1
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} else if n < 1<<16 {
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return 2
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} else if n < 1<<24 {
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return 3
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} else if n < 1<<32 {
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return 4
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} else if n < 1<<40 {
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return 5
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} else if n < 1<<48 {
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return 6
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} else if n < 1<<56 {
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return 7
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}
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return 8
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}
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