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// Copyright 2019 The GoPacket Authors. All rights reserved.
//
// Use of this source code is governed by a BSD-style license
// that can be found in the LICENSE file in the root of the source
// tree.
//go:build ignore
// +build ignore
// This file generates LayersDecoder function for DecodingLayerContainer
// go run gen.go | gofmt > layers_decoder.go
package main
import (
"fmt"
"os"
"time"
)
const headerFmt = `// Copyright 2019 The GoPacket Authors. All rights reserved.
package gopacket
// Created by gen.go, don't edit manually
// Generated at %s
// LayersDecoder returns DecodingLayerFunc for specified
// DecodingLayerContainer, LayerType value to start decoding with and
// some DecodeFeedback.
func LayersDecoder(dl DecodingLayerContainer, first LayerType, df DecodeFeedback) DecodingLayerFunc {
firstDec, ok := dl.Decoder(first)
if !ok {
return func([]byte, *[]LayerType) (LayerType, error) {
return first, nil
}
}
`
var funcBody = `return func(data []byte, decoded *[]LayerType) (LayerType, error) {
*decoded = (*decoded)[:0] // Truncated decoded layers.
typ := first
decoder := firstDec
for {
if err := decoder.DecodeFromBytes(data, df); err != nil {
return LayerTypeZero, err
}
*decoded = append(*decoded, typ)
typ = decoder.NextLayerType()
if data = decoder.LayerPayload(); len(data) == 0 {
break
}
if decoder, ok = dlc.Decoder(typ); !ok {
return typ, nil
}
}
return LayerTypeZero, nil
}`
func main() {
fmt.Fprintf(os.Stderr, "Writing results to stdout\n")
types := []string{
"DecodingLayerSparse",
"DecodingLayerArray",
"DecodingLayerMap",
}
fmt.Printf(headerFmt, time.Now())
for _, t := range types {
fmt.Printf("if dlc, ok := dl.(%s); ok {", t)
fmt.Println(funcBody)
fmt.Println("}")
}
fmt.Println("dlc := dl")
fmt.Println(funcBody)
fmt.Println("}")
}
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