pynetdicom.pdu_items.PresentationContextItemAC

class pynetdicom.pdu_items.PresentationContextItemAC

A Presentation Context (AC) Ttem.

Presentation Contexts (AC) Items are used by the association acceptor to signal which Abstract Syntaxes and Transfer Syntaxes have been accepted or rejected.

Notes

A Presentation Context (AC) Item requires the following parameters:

• Item type (1, fixed value, 0x21)

• Item length (1)

• Presentation context ID (1)

• Result/reason (1)

• Transfer Syntax Sub-item (1)

  • Item type (1, fixed, 0x40)

  • Item length (1)

  • Transfer syntax name (1)

Encoding

When encoded, a Presentation Context (AC) Item has the following structure, taken from Part 8, Table 9-13 of the DICOM Standard (offsets shown with Python indexing). Items are always encoded using Big Endian.

Offset	Length	Description
0	1	Item type
1	1	Reserved
2	2	Item length
4	1	Presentation context ID
5	1	Reserved
6	1	Result/reason
7	1	Reserved
8	Variable	Transfer syntax sub-item

References

• DICOM Standard, Part 8, Section 9.3.3.2

• DICOM Standard, Part 8, Section 9.3.1

__init__() → None

Initialise a new Presentation Context (AC) Item.

Methods

__init__()	Initialise a new Presentation Context (AC) Item.
decode(bytestream)	Decode bytestream and use the result to set the field values of the PDU item.
encode()	Return the encoded PDU as bytes.
from_primitive(primitive)	Set the item's values using a Presentation Context primitive.
to_primitive()	Return a PresentationContext primitive from the current Item.

Attributes

context_id	Return the item's Presentation Context ID field value.
item_length	Return the item's Item Length field value as int.
item_type	Return the item's Item Type field value as int.
result	Return the item's Result/reason field value.
result_str	Get a string describing the result.
transfer_syntax	Return the Transfer Syntax, if available.

property context_id: Optional[int]

Return the item’s Presentation Context ID field value.

from_primitive(primitive: PresentationContext) → None

Set the item’s values using a Presentation Context primitive.

Parameters

primitive (presentation.PresentationContext) – The primitive to use to set the Item’s field values.

property item_length: int

Return the item’s Item Length field value as int.

property result: Optional[int]

Return the item’s Result/reason field value.

property result_str: str

Get a string describing the result.

to_primitive() → PresentationContext

Return a PresentationContext primitive from the current Item.

Returns

The primitive representation of the current Item.

Return type

presentation.PresentationContext

property transfer_syntax: Optional[UID]

Return the Transfer Syntax, if available.

Returns

If no Transfer Syntax Sub-item or an empty Transfer Syntax Sub-item has been sent by the Acceptor then returns None, otherwise returns the Transfer Syntax Sub-item’s transfer syntax UID.

Return type

pydicom.uid.UID or None