mirror of https://github.com/octoleo/restic.git
76 lines
2.0 KiB
Go
76 lines
2.0 KiB
Go
// Copyright 2017, OpenCensus Authors
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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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//
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// Package tagencoding contains the tag encoding
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// used interally by the stats collector.
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package tagencoding // import "go.opencensus.io/internal/tagencoding"
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// Values represent the encoded buffer for the values.
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type Values struct {
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Buffer []byte
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WriteIndex int
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ReadIndex int
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}
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func (vb *Values) growIfRequired(expected int) {
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if len(vb.Buffer)-vb.WriteIndex < expected {
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tmp := make([]byte, 2*(len(vb.Buffer)+1)+expected)
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copy(tmp, vb.Buffer)
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vb.Buffer = tmp
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}
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}
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// WriteValue is the helper method to encode Values from map[Key][]byte.
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func (vb *Values) WriteValue(v []byte) {
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length := len(v) & 0xff
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vb.growIfRequired(1 + length)
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// writing length of v
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vb.Buffer[vb.WriteIndex] = byte(length)
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vb.WriteIndex++
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if length == 0 {
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// No value was encoded for this key
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return
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}
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// writing v
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copy(vb.Buffer[vb.WriteIndex:], v[:length])
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vb.WriteIndex += length
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}
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// ReadValue is the helper method to decode Values to a map[Key][]byte.
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func (vb *Values) ReadValue() []byte {
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// read length of v
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length := int(vb.Buffer[vb.ReadIndex])
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vb.ReadIndex++
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if length == 0 {
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// No value was encoded for this key
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return nil
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}
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// read value of v
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v := make([]byte, length)
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endIdx := vb.ReadIndex + length
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copy(v, vb.Buffer[vb.ReadIndex:endIdx])
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vb.ReadIndex = endIdx
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return v
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}
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// Bytes returns a reference to already written bytes in the Buffer.
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func (vb *Values) Bytes() []byte {
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return vb.Buffer[:vb.WriteIndex]
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}
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