https://github.com/skythen/bertlv

Golang implementation of parsing and building BER-TLV.
https://github.com/skythen/bertlv

bertlv constructed-objects

Last synced: 5 months ago
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Golang implementation of parsing and building BER-TLV.

• Host: GitHub
• URL: https://github.com/skythen/bertlv
• Owner: skythen
• License: mit
• Created: 2021-01-07T14:33:24.000Z (over 5 years ago)
• Default Branch: master
• Last Pushed: 2021-05-16T11:25:47.000Z (about 5 years ago)
• Last Synced: 2024-06-21T04:47:33.927Z (almost 2 years ago)
• Topics: bertlv, constructed-objects
• Language: Go
• Homepage:
• Size: 28.3 KB
• Stars: 8
• Watchers: 2
• Forks: 5
• Open Issues: 0
• Metadata Files:
  • Readme: README.md
  • License: LICENSE

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README

          
# BER-TLV

[![Build Status](https://travis-ci.org/skythen/bertlv.svg?branch=master)](https://travis-ci.org/skythen/bertlv)

[![Coverage Status](https://coveralls.io/repos/github/skythen/bertlv/badge.svg?branch=master)](https://coveralls.io/github/skythen/bertlv?branch=master)

[![GoDoc](https://godoc.org/github.com/skythen/bertlv?status.svg)](http://godoc.org/github.com/skythen/bertlv)

[![Go Report Card](https://goreportcard.com/badge/github.com/skythen/bertlv)](https://goreportcard.com/report/github.com/skythen/bertlv)

Package bertlv implements parsing and building of BER-TLV structures.

Please note that this is not a complete implementation of the X.690 standard as it is agnostic about classes (Universal, Application, Context-specific, Private) and therefore does not check for correct encoding of tags/values.

`go get github.com/skythen/bertlv`

## Parse

You can parse BER-TLV encoded data from bytes:

```go

b := []byte{0x71, 0x10, 0xB0, 0x0E, 0x0F, 0x05, 0x01, 0x02, 0x03, 0x04, 0x05, 0x0E, 0x05, 0x05, 0x04, 0x03, 0x02, 0x01}

bertlvs, err := Parse(b)

```

### Constructed objects

You can check if a BerTLV is constructed and get first or all children or filter child objects by tag:

```go

if bertlvs[0].Tag.IsConstructed() {

    child := bertlvs[0].FirstChild(NewOneByteTag(0x0F))

}

```

## Create

You can create single BER-TLVs with NewBerTLV:

```go

val := []byte{0xB0, 0x0E, 0x0F, 0x05, 0x01, 0x02, 0x03, 0x04, 0x05, 0x0E, 0x05, 0x05, 0x04, 0x03, 0x02, 0x01}

bertlv, err := NewBerTLV(NewOneByteTag(0x71), val)

```

If you want to create complex constructed objects you use the Builder:

```go

builder := Builder{}

nestedBuilder := Builder{}

anotherNestedBuilder := Builder{}

berTlvs, err := builder.AddBytes(NewOneByteTag(0x71), 			     // first level, constructed object

    nestedBuilder.AddBytes(NewOneByteTag(0xB0), 		             // second level, constructed object

        anotherNestedBuilder.

            AddBytes(NewOneByteTag(0x0F), []byte{0x01, 0x02, 0x03, 0x04, 0x05}). // third level primitive object

            AddBytes(NewOneByteTag(0x0E), []byte{0x05, 0x04, 0x03, 0x02, 0x01}). // third level primitive object

        Bytes()).

    Bytes()).

BuildBerTLVs()

```

You can also use

- builder.AddEmpty() to add objects without value

- builder.AddByte() to add objects with a value that consists of a single byte

- builder.AddRaw() to add raw bytes