90 lines
2.2 KiB
Python
90 lines
2.2 KiB
Python
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#!/usr/bin/env python
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# -*- coding: utf-8 -*-
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#
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"""
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csp (Carriage-Return seperation protocol)
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=========================================
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**Author:**
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* Dirk Alders <sudo-dirk@mount-mockery.de>
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**Description:**
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This module is a submodule of :mod:`stringtools` and creates an frame to transmit and receive messages via an serial interface.
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**Submodules:**
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* :class:`stringtools.csp.csp`
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* :func:`stringtools.csp.build_frame`
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"""
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import stringtools
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import logging
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import sys
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logger_name = 'STRINGTOOLS'
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logger = logging.getLogger(logger_name)
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DATA_SEPERATOR = b'\n'
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class csp(object):
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"""This class extracts messages from an "csp-stream".
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**Example:**
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.. literalinclude:: ../examples/csp.csp.py
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Will result to the following output:
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.. literalinclude:: ../examples/csp.csp.log
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"""
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LOG_PREFIX = 'CSP:'
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def __init__(self, seperator=DATA_SEPERATOR):
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self.__buffer__ = b''
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self.__seperator__ = seperator
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def process(self, data):
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"""
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This processes a byte out of a "stp-stream".
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:param bytes data: A byte stream
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:returns: A list of the extracted message(s)
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:rtype: list
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"""
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if sys.version_info < (3, 0):
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if type(data) is unicode:
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raise TypeError
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#
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rv = (self.__buffer__ + data).split(self.__seperator__)
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self.__buffer__ = rv.pop()
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if len(self.__buffer__) != 0:
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logger.debug('%s Leaving data in buffer (to be processed next time): %s', self.LOG_PREFIX, stringtools.hexlify(self.__buffer__))
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for msg in rv:
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logger.info('%s message identified - %s', self.LOG_PREFIX, stringtools.hexlify(msg))
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return rv
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def build_frame(msg, seperator=DATA_SEPERATOR):
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"""This Method builds an "csp-frame" to be transfered via a stream.
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:param str data: A String (Bytes) to be framed
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:returns: The "csp-framed" message to be sent
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:rtype: str
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**Example:**
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.. literalinclude:: ../examples/csp.build_frame.py
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Will result to the following output:
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.. literalinclude:: ../examples/csp.build_frame.log
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"""
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if seperator in msg:
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raise ValueError
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else:
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return msg + seperator
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