libnbt++ `libnbtplusplus/`

Type: NBT Format Library
License: LGPL-3.0 Fork Origin: GitHub
Status: Detached Fork (independently maintained)
Format: Minecraft Named Binary Tag Latest Version: 0.0.5-1

Overview

libnbt++ is a free C++ library for Minecraft's Named Binary Tag (NBT) file format. It can read and write compressed and uncompressed NBT files and provides a code interface for working with NBT data.

Version History

libnbt++ 1 — Original library (deprecated)
libnbt++ 2 — Rewritten with cleaner API (deprecated)
libnbt++ 3 — Current version used by ProjT Launcher

Usage in ProjT Launcher

libnbt++ is used for:

World data — Reading level.dat and player data
Server data — Parsing server.dat files
Mod integration — Processing NBT-based configurations
Backup/export — Instance data serialization

Features

Feature	Status
NBT reading	✅
NBT writing	✅
GZip compression	✅
Zlib compression	✅
Big-endian support	✅
Little-endian (Bedrock)	⚠️ Limited

Supported Tag Types

Type ID	Tag Name	C++ Type
0	TAG_End	—
1	TAG_Byte	`int8_t`
2	TAG_Short	`int16_t`
3	TAG_Int	`int32_t`
4	TAG_Long	`int64_t`
5	TAG_Float	`float`
6	TAG_Double	`double`
7	TAG_Byte_Array	`std::vector<int8_t>`
8	TAG_String	`std::string`
9	TAG_List	`nbt::tag_list`
10	TAG_Compound	`nbt::tag_compound`
11	TAG_Int_Array	`std::vector<int32_t>`
12	TAG_Long_Array	`std::vector<int64_t>`

Build Instructions

Prerequisites

C++11 compatible compiler
CMake 3.15 or later
ZLIB (optional, for compression support)

Build Steps

cd libnbtplusplus
mkdir build && cd build
cmake ..
cmake --build .

CMake Options

Option	Description	Default
`NBT_BUILD_SHARED`	Build shared library	`OFF`
`NBT_USE_ZLIB`	Enable zlib support	`ON`
`NBT_BUILD_TESTS`	Build tests	`ON`

API Usage

Reading NBT

#include <nbt_tags.h>
#include <io/stream_reader.h>
#include <fstream>

std::ifstream file("level.dat", std::ios::binary);
nbt::io::stream_reader reader(file, endian::big);

// Read compound tag
auto result = reader.read_compound();
nbt::tag_compound& root = result.first;
std::string name = result.second;

// Access data
auto& level = root["Data"].as<nbt::tag_compound>();
std::string levelName = level["LevelName"].as<nbt::tag_string>();
int32_t gameType = level["GameType"].as<nbt::tag_int>();

Writing NBT

{% raw %}

#include <nbt_tags.h>
#include <io/stream_writer.h>
#include <fstream>

nbt::tag_compound data;
data["LevelName"] = nbt::tag_string("My World");
data["GameType"] = nbt::tag_int(0);  // Survival

std::ofstream file("level.dat", std::ios::binary);
nbt::io::stream_writer writer(file, endian::big);
writer.write_tag("", nbt::tag_compound{{"Data", std::move(data)}});

{% endraw %}

Working with Lists

// Create a list of strings
nbt::tag_list items(nbt::tag_type::String);
items.push_back(nbt::tag_string("item1"));
items.push_back(nbt::tag_string("item2"));

// Access list
for (const auto& item : root["Items"].as<nbt::tag_list>()) {
    std::cout << item.as<nbt::tag_string>().get() << std::endl;
}

Testing

cd libnbtplusplus/build
ctest -V

Documentation

Resource	Location
API Headers	`libnbtplusplus/include/`
Tests	`libnbtplusplus/test/`
License	`libnbtplusplus/COPYING`, `libnbtplusplus/COPYING.LESSER`
Upstream Wiki	GitHub Wiki

Copyright & Licensing

Full license: libnbtplusplus/COPYING