0.3.0

Add streaming-safe MessagePack decoder

Add MessagePackStreamingDecoder, a new decoder class designed for use with streaming data sources. Unlike MessagePackDecoder, which assumes all data is available and will corrupt the reader on partial reads, the streaming decoder peeks at format bytes and length fields before consuming any data. If insufficient data is available, it returns NotEnoughData with zero bytes consumed, allowing the caller to append more data and retry.

Example Usage

// Decode values as chunks of data arrive.
// Call append() with each chunk, then next() to attempt decoding.
// next() returns NotEnoughData if more bytes are needed,
// InvalidData if the stream is corrupt, or a decoded value.
let sd = MessagePackStreamingDecoder
sd.append(chunk)

match sd.next()
| let v: U32 => // got a value
| let s: String val => // got a string
| let t: MessagePackTimestamp => // got a timestamp
| let a: MessagePackArray => // array header; read a.size elements
| let m: MessagePackMap => // map header; read m.size key-value pairs
| NotEnoughData => // append more data and retry
| InvalidData => // stream is corrupt
end

Change timestamp nsec type from I64 to U32

The nanoseconds component of decoded timestamps is now U32 instead of I64. This affects MessagePackDecoder.timestamp() (return type changed from (I64, I64) to (I64, U32)) and MessagePackTimestamp.nsec (field type changed from I64 to U32).

This is a breaking change. Code that destructures the decoder's return value or reads the nsec field will need to account for the new type. The encoder already accepted U32 for nanoseconds, so encoding code is unaffected.

Before

// MessagePackDecoder.timestamp()
(let sec: I64, let nsec: I64) =
  MessagePackDecoder.timestamp(reader)?

// MessagePackTimestamp.nsec
let ts: MessagePackTimestamp = ...
let nsec: I64 = ts.nsec

After

// MessagePackDecoder.timestamp()
(let sec: I64, let nsec: U32) =
  MessagePackDecoder.timestamp(reader)?

// MessagePackTimestamp.nsec
let ts: MessagePackTimestamp = ...
let nsec: U32 = ts.nsec

Add compact encoding and decoding methods

MessagePackEncoder and MessagePackDecoder now provide compact methods that automatically select the smallest wire format for a given value, per the MessagePack spec recommendation. The format-specific methods remain available for explicit control.

Encoder

let w: Writer ref = Writer

// Integer — picks positive_fixint, uint_8, ..., or uint_64
MessagePackEncoder.uint(w, 42)

// Signed — uses unsigned formats for positive values
MessagePackEncoder.int(w, -100)

// String — picks fixstr, str_8, str_16, or str_32
MessagePackEncoder.str(w, "hello")?

// Binary — picks bin_8, bin_16, or bin_32
MessagePackEncoder.bin(w, data)?

// Array header — picks fixarray, array_16, or array_32
MessagePackEncoder.array(w, 3)

// Map header — picks fixmap, map_16, or map_32
MessagePackEncoder.map(w, 2)

// Extension — prefers fixext for sizes 1/2/4/8/16
MessagePackEncoder.ext(w, ext_type, data)?

// Timestamp — picks timestamp_32, _64, or _96
MessagePackEncoder.timestamp(w, seconds, nanoseconds)?

Decoder

let b: Reader ref = Reader

// Reads any unsigned integer format
let n: U64 = MessagePackDecoder.uint(b)?

// Reads any signed or unsigned integer format
let i: I64 = MessagePackDecoder.int(b)?

// str() now handles fixstr in addition to str_8/str_16/str_32
// (previously, fixstr required calling fixstr() directly)
let s: String iso^ = MessagePackDecoder.str(b)?

// Reads any array header format
let count: U32 = MessagePackDecoder.array(b)?

// Reads any map header format
let pairs: U32 = MessagePackDecoder.map(b)?

[0.3.0] - 2026-02-08

Added

• Add streaming-safe MessagePack decoder (PR #52)
• Add compact encoding and decoding methods (PR #60)

Changed

• Change timestamp nsec type from I64 to U32 (PR #56)