Unpacker extension type

A high-performance MessagePack deserializer.

Unpacker is implemented as an extension type over a BinaryReader from pro_binary, providing a zero-overhead wrapper for decoding MessagePack data.

Features:

  • Zero-Overhead: No extra memory or object allocation for the wrapper.
  • Efficient Decoding: Stream-like parsing with minimal branching.
  • Buffer Reuse: Supports rebind to switch buffers without re-allocating the reader or unpacker instances.

Example:

final unpacker = Unpacker(buffer: bytes);
final data = unpacker.unpack();
on
  • _UnpackerState

Constructors

Unpacker({required Uint8List buffer, DecodeExt? decodeExt})
Creates a new Unpacker for the given buffer.
Unpacker.withEmptyBuffer({DecodeExt? decodeExt})
Creates an Unpacker with an empty buffer, ready to be rebind-ed.

Properties

hasBytesAvailable → bool
Whether there are more bytes to read in the current buffer.
no setter
offset → int
The current read position in the underlying buffer.
no setter
remainingBytes → Uint8List
Returns the bytes remaining in the buffer from the current position.
no setter

Methods

readBytes(int length) → Uint8List
Reads length bytes directly from the underlying buffer.
rebind(Uint8List buffer) → void
Rebinds the underlying BinaryReader to a new buffer without creating a new Unpacker instance.
skip() → void
Advances past exactly one complete value of any type (scalar, string, binary, array, map, ext, nil), leaving the reader positioned at the next value. For an array or map it skips the header and all nested elements recursively.
unpack() → dynamic
Unpacks the next object from the buffer, automatically detecting its type.
unpackArray() → List?
Unpacks the next value as an array (List).
unpackArrayLength() → int
Reads only the next array header and returns its element count.
unpackArrayOf<T>() → List<T>
Unpacks the next value as an array of a specific type T.
unpackAs<T>() → T
Unpacks the next value as the expected type T.
unpackBinary() → Uint8List?
Unpacks the next value as binary data (Uint8List).
unpackBool() → bool?
Unpacks the next value as a boolean.
unpackDouble() → double?
Unpacks the next value as a double (float 32 or float 64).
unpackExt<T>() → T
Unpacks the next value as a custom extension type T.
unpackInt() → int?
Unpacks the next value as an integer.
unpackMap() → Map?
Unpacks the next value as a Map.
unpackMapLength() → int
Reads only the next map header and returns its entry count.
unpackMapOf<K, V>() → Map<K, V>
Unpacks the next value as a map with keys of type K and values of type V.
unpackString() → String?
Unpacks the next value as a String.
unpackTimestamp() → DateTime?
Unpacks the next value as a MessagePack timestamp extension (DateTime).