Header Type - JAM

class jam.types.header.TicketsMark(initial: Sequence[T] = [], codec: Codec[T] | None = None)[source]

Bases: Array[TicketBody]

static decode_from(buffer: bytes | bytearray | memoryview, offset: int = 0) → Tuple[Any, int]

Decode from buffer. Must be implemented by subclasses or added via decorator.

Parameters:

buffer – Buffer to decode from
offset – Starting position in buffer

Returns:

The decoded value
Number of bytes read

Return type:

Tuple containing

class jam.types.header.OffendersMark(initial: Sequence[T] = [], codec: Codec[T] | None = None)[source]

Bases: Vector[ByteArray32]

static decode_from(buffer: bytes | bytearray | memoryview, offset: int = 0) → Tuple[Vector[T], int]

Decode from buffer. Must be implemented by subclasses or added via decorator.

Parameters:

buffer – Buffer to decode from
offset – Starting position in buffer

Returns:

The decoded value
Number of bytes read

Return type:

Tuple containing

class jam.types.header.OptionalEpochMark(initial: Codable = Null)[source]

Bases: Option

static decode_from(buffer: bytes | bytearray | memoryview, offset: int = 0) → Tuple[Option, int]

Decode option from buffer.

Parameters:

optional_type – Type of the optional value
buffer – Source buffer
offset – Starting offset

Returns:

Tuple of (decoded value, bytes read)

Raises:

DecodeError – If buffer is invalid or too short
ValueError – If types list is empty

class jam.types.header.OptionalTicketsMark(initial: Codable = Null)[source]

Bases: Option

static decode_from(buffer: bytes | bytearray | memoryview, offset: int = 0) → Tuple[Option, int]

Decode option from buffer.

Parameters:

optional_type – Type of the optional value
buffer – Source buffer
offset – Starting offset

Returns:

Tuple of (decoded value, bytes read)

Raises:

DecodeError – If buffer is invalid or too short
ValueError – If types list is empty

class jam.types.header.Header(parent: ByteArray32, parent_state_root: ByteArray32, extrinsic_hash: ByteArray32, slot: U32, epoch_mark: OptionalEpochMark, tickets_mark: OptionalTicketsMark, offenders_mark: OffendersMark, author_index: U16, entropy_source: ByteArray96, seal: ByteArray96)[source]

Bases: Codable, JsonSerde

Block header structure.

parent: ByteArray32

parent_state_root: ByteArray32

extrinsic_hash: ByteArray32

slot: U32

epoch_mark: OptionalEpochMark

tickets_mark: OptionalTicketsMark

offenders_mark: OffendersMark

author_index: U16

entropy_source: ByteArray96

seal: ByteArray96

__init__(parent: ByteArray32, parent_state_root: ByteArray32, extrinsic_hash: ByteArray32, slot: U32, epoch_mark: OptionalEpochMark, tickets_mark: OptionalTicketsMark, offenders_mark: OffendersMark, author_index: U16, entropy_source: ByteArray96, seal: ByteArray96) → None

Initialize the Codable.

Parameters:

codec – Optional codec to use for encoding/decoding
enc_sequence – Optional function that returns sequence of fields to encode

static decode_from(buffer: bytes | bytearray | memoryview, offset: int = 0) → Tuple[T, int]

Decode from buffer. Must be implemented by subclasses or added via decorator.

Parameters:

buffer – Buffer to decode from
offset – Starting position in buffer

Returns:

The decoded value
Number of bytes read

Return type:

Tuple containing

encode_into(buffer: bytearray, offset: int = 0) → int: Encode into provided buffer.

encode_size() → int: Calculate number of bytes needed to encode.