pynetdicom.pdu_items.PresentationContextItemAC

class pynetdicom.pdu_items.PresentationContextItemAC[source][source]

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.

item_length

The number of bytes from the first byte following the Item Length field to the last byte of the Item.

Type:int
item_type

The Item Type field value (0x21).

Type:int
presentation_context_id

The Presentation Context ID field value, an odd integer between 1 and 255.

Type:int or None
result_reason

The Presentation Context’s Result/reason field value.

Type:int
transfer_syntax

The Presentation Context Item’s Transfer Syntax (if available).

Type:list of pydicom.uid.UID
transfer_syntax_sub_item

The Presentation Context Items’ Transfer Syntax Sub-item field value.

Type:list of pynetdicom.uid.UID

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 Table 9-13 [1] (offsets shown with Python indexing). Items are always encoded using Big Endian [2].

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

[1]DICOM Standard, Part 8, Section 9.3.3.2
[2]DICOM Standard, Part 8, Section 9.3.1
__init__()[source][source]

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 an int.
item_type Return the item’s Item Type field value as an 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.
context_id

Return the item’s Presentation Context ID field value.

decode(bytestream)[source]

Decode bytestream and use the result to set the field values of the PDU item.

Parameters:bytestream (bytes) – The PDU data to be decoded.
encode()[source]

Return the encoded PDU as bytes.

Returns:The encoded PDU.
Return type:bytes
from_primitive(primitive)[source][source]

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.
item_length

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

item_type

Return the item’s Item Type field value as an int.

result

Return the item’s Result/reason field value.

result_str

Get a string describing the result.

to_primitive()[source][source]

Return a PresentationContext primitive from the current Item.

Returns:The primitive representation of the current Item.
Return type:presentation.PresentationContext
transfer_syntax

Return the Transfer Syntax, if available.

Returns:
Return type:pydicom.uid.UID or None