PyChapter10¶
PyChapter10 is an open source pure Python library for reading and writing IRIG 106 Chapter 10 (now 11) files.
Library Overview¶
Basic Structure & Usage¶
PyChapter10 makes every effort to provide a pythonic interface to Chapter 10 data as in the following example:
for packet in C10('file.c10'):
for message in packet:
print(message.rtc)
The top-level C10 object represents a given Chapter 10 file or stream. C10 objects contain Packet objects of various data types. Packets often consist of a number of messages which can also be iterated over.
All of these types and classes respond to the usual python introspection resources such as help() and dir().
Data Type Descriptions¶
Data formats are specified using a wrapper around bitstruct. Every data type has a channel specific data word (CSDW) that may look something like this (Ethernet given as an example):
class EthernetF0(packet.Packet):
# ...
csdw_format = BitFormat('''
u16 count
p9
u3 ttb
u4 format''')
Similar to a C struct fields are specified with a type (uint by default) and bit length. “p” signifies padding or “reserved” as the chapter 10 standard may call it. Various data types will also specify the format of the messages they contain be that 1553, ethernet, etc. Going back to the Ethernet example:
class EthernetF0(packet.Packet):
# ...
class Message(packet.Message):
# ...
def __repr__(self):
return '<Ethernet frame %s bytes>' % len(self.data)
FORMAT = BitFormat('''
u64 ipts
u14 length
u1 data_length_error
u1 data_crc_error
u8 network_id
u1 crc_error
u1 frame_error
u2 content
u4 ethernet_speed''')
Now we have the intra-packet/message header defined and since it includes a “length” field the appropriate number of bytes are read each time we get a new message. We also define a “__repr__” function to help with debugging.
Contributing¶
Feedback, issues, and pull requests are all welcome on the main repo. See the CONTRIBUTING document in github for more details. If you’re not sure where to get started check out the issue tracker on github.