Implements Minecraft's NBT format serialization, supporting all NBT variants and compressions. Offers type-safe `NbtTag` classes with convenient DSLs for data encoding/decoding to/from NBT or SNBT formats.
An implementation of Minecraft's NBT format for kotlinx.serialization.
Technical information about NBT can be found here.
NbtTag classes, with convenient builder DSLsNbt and StringifiedNbt are used to encode/decode @Serializable data.
import net.benwoodworth.knbt.*
val nbt = Nbt {
variant = NbtVariant. // Java, Bedrock, BedrockNetwork
compression = NbtCompression. // None, Gzip, Zlib
//compressionLevel = null // in 0..9
//encodeDefaults = false
//ignoreUnknownKeys = false
//serializersModule = EmptySerializersModule
}
val snbt = StringifiedNbt {
//prettyPrint = false
//prettyPrintIndent = " "
//encodeDefaults = false
}
// ByteArray
byteArray = nbt.encodeToByteArray(data)
data = nbt.decodeFromByteArray(byteArray)
// NbtTag
nbtTag = nbt.encodeToNbtTag(data)
data = nbt.decodeFromNbtTag(nbtTag)
// Okio Sink/Source (Multiplatform)
nbt.encodeToSink(data, sink)
data = nbt.decodeFromSource(source)
// OutputStream/InputStream (JVM)
nbt.encodeToStream(data, outputStream)
data = nbt.decodeFromStream(inputStream)
string = snbt.encodeToString()
= snbt.decodeFromString(string)
Serializable classes will have their @SerialName used for the root tag's name.
@Serializable
@SerialName("root")
class Example(val string: String, val int: Int)
// Serializes to: {root : {string : "Hello, world!", int : 42}}
nbt.encodeToNbtTag(Example(string = "Hello, World!", int = 42))
import kotlin.io.path.*
import net.benwoodworth.knbt.*
val file = Path("file.nbt")
val nbt = Nbt {
TODO()
}
// Read from file
val tag: NbtTag = file.inputStream().use { input ->
nbt.decodeFromStream(input)
}
// Write to file
file.outputStream().use { output ->
nbt.encodeToStream(tag, output)
}
NbtTagsNbtTags can be created with constructors and builder functions:
Using the same version of kotlinx.serialization is recommended since parts of its API required for custom formats are still experimental, and newer versions may have binary-incompatible changes that could break knbt's implementation.
While in beta, all new minor releases (v0.#.0) will have breaking API/functionality changes. Read the release notes for information.
Replacement refactorings will be provided where possible for broken APIs. Change the minor version one at a time (e.g. 0.1.0 -> 0.2.0 -> 0.3.0) and apply quick fixes. Deprecated APIs will then be removed in 0.#.1 releases.
plugins {
kotlin("jvm") version "2.2.21" // or kotlin("multiplatform"), etc.
//kotlin("plugin.serialization") version "2.2.21"
}
repositories {
mavenCentral()
//maven("https://central.sonatype.com/repository/maven-snapshots/")
}
dependencies {
implementation("net.benwoodworth.knbt:knbt:$knbt_version")
//implementation("com.squareup.okio:okio:3.16.2")
}
sealed interface NbtTag
class NbtByte : NbtTag
class NbtShort : NbtTag
class NbtInt : NbtTag
class NbtLong : NbtTag
class NbtFloat : NbtTag
class NbtDouble : NbtTag
class NbtString : NbtTag
class NbtByteArray : NbtTag, List<Byte>
class NbtIntArray : NbtTag, List<Int>
class NbtLongArray : NbtTag, List<Long>
class NbtList<T : NbtTag> : NbtTag, List<T> // Only contains entries of a single type
class NbtCompound : NbtTag, Map<String, NbtTag>
val nbtByte = NbtByte(5)
val boolean = NbtByte(true)
val nbtIntArray = NbtIntArray(intArrayOf(1, 2, 3, 4, 5))
val nbtListOfStrings = buildNbtList {
add("these")
add("are")
add("strings")
}
val nbtCompound = buildNbtCompound {
put("int", 1)
put("string", ":)")
put("byteArray", byteArrayOf(1, 1, 2, 3, 5, 8))
putNbtList("floatList") {
add(3f)
add(1f)
add(4f)
}
}
val bigtest = buildNbtCompound("Level") {
put("longTest", 9223372036854775807L)
put("shortTest", 32767.toShort())
put("stringTest", "HELLO WORLD THIS IS A TEST STRING ÅÄÖ!")
put("floatTest", 0.49823147f)
put("intTest", 2147483647)
putNbtCompound("nested compound test") {
putNbtCompound("ham") {
put("name", "Hampus")
put("value", 0.75f)
}
putNbtCompound("egg") {
put("name", "Eggbert")
put("value", 0.5f)
}
}
putNbtList("listTest (long)") {
add(11L)
add(12L)
add(13L)
add(14L)
add(15L)
}
putNbtList("listTest (compound)") {
addNbtCompound {
put("name", "Compound tag #0")
put("created-on", 1264099775885L)
}
addNbtCompound {
put("name", "Compound tag #1")
put("created-on", 1264099775885L)
}
}
put("byteTest", 127.toByte())
put(
"byteArrayTest (the first 1000 values of (n*n*255+n*7)%100, starting with n=0 (0, 62, 34, 16, 8, ...))",
ByteArray(1000) { n -> ((n * n * 255 + n * 7) % 100).toByte() }
)
put("doubleTest", 0.4931287132182315)
}
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