frogstair / nbt

Library to parse and generate NBT data in Go

NBT for Go

This is a simple NBT encoder/decoder that does not use any custom structs/types that supports compression

Supported types of data

For now it can only encode/decode tags whose root node is a composite, other types are coming in the near future. It can also only encode/decode maps, and support for structs and struct tags will also be added later

Features

• Easy to represent data with map syntax
• Compression with gzip
• Fast
• No external libraries
• Very compact
• A more compact wrapper to improve readability

Precautions

It is necessary to explicitly specify a type for each numerical value because of how NBT works. If not specified, the smallest fitting type would be used, except floating point numbers, where the default float64 is used.

Since nbt uses signed bytes, it is necessary to not use byte in the map, cast it to int8 instead.

Example

package main

import (
    "encoding/json"
    "fmt"
    "io/ioutil"
    "os"

    "github.com/frogstair/nbt"
)

func main() {

    // Sample data to work with
    data := map[string]interface{}{
        "nested": nbt.C{
            "egg": nbt.C{
                "name":  "Eggbert",
                "value": 0.5,
            },
            "ham": nbt.C{
                "name":  "Hambert",
                "value": 0.75,
            },
        },
        "listTest (compound)": []nbt.C{
            {
                "createdOn": int64(1264099775885),
                "name":      "nbt.Compound Tag #0",
            },
            {
                "createdOn": int64(1264099775885),
                "name":      "nbt.Compound Tag #1",
            },
        },
        "empty": []int64{},
        // No need to specify type here, because go will force every number to be an int64
        "listTest (long)": []int64{
            11,
            12,
            13,
            14,
            15,
        },
        "byteTest":   int8(127),
        "shortTest":  int16(32767),
        "intTest":    int32(2147483647),
        "longTest":   int64(9223372036854775807),
        "guessInt8":  42,
        "guessInt16": 4242,
        "guessInt32": 424242,
        "guessInt64": 42424242424242,
        // Will be printed as base64 encoded because thats how JSON works
        "byteArr": []int8{1, 2, 3, 4, 5},
        // Support for unicode
        "stringTest": "HELLO WORLD THIS IS A TEST STRING! こんにちは世界〜",
    }

    // Encode the data as bytes and compress it with gzip
    b := nbt.EncodeCompress(data, "")
    // Write data to a file
    ioutil.WriteFile("./bigtest.nbt", b, 0644)

    // Open the file with the data
    f, _ := os.Open("bigtest.nbt")
    // Make an empty container
    m := make(map[string]interface{})

    // Decode compressed file stream. Any reader that contains the NBT data works
    err := nbt.DecodeCompressedStream(f, &m)
    if err != nil {
        panic(err)
    }

    // Pretty print the map using JSON
    t, _ := json.MarshalIndent(m, "", "  ")
    fmt.Print(string(t), "\n")
}

This example can also be found in the examples folder