Module Gnumed.pycommon.gmSerialTools

"""GNUmed serial port tools.

These functions are complementing pySerial.
"""
#===========================================================================
__version__ = "$Revision: 1.3 $"
__author__ = "K.Hilbert <Karsten.Hilbert@gmx.net>"
__licence__ = "GPL v2 or later (details at https://www.gnu.org)"

import time, logging


_log = logging.getLogger('gm.serial')
_log.info(__version__)
#----------------------------------------------------
# general utility
#----------------------------------------------------
def wait_for_str(aDrv = None, aString = '', aTimeout = 2500, max_bytes = 2048):
        """Wait for a particular string with timeout.

        - timeout in milliseconds, please
        """
        if aString == '':
                return (1, '')

        if aDrv is None:
                _log.error("need source for incoming data")
                return (0, '')

        if max_bytes < len(aString):
                max_bytes = len(aString) + 1

        rxd = ''
        loop = 0
        slice = 100
        # how many loops ?
        max_loops = abs(aTimeout / slice)
        # wait for data
        while loop < max_loops:
                loop += 1
                # something there
                if aDrv.inWaiting() > 0:
                        # get all there is
                        while aDrv.inWaiting() > 0:
                                rxd = rxd + aDrv.read(size = 1)
                                # did this contain our expected string already ?
                                if rxd.find(aString) > -1:
                                        return (1, rxd)
                                # did we exceed our character buffer limit ?
                                # this stops runaway serial ports
                                if len(rxd) >= max_bytes:
                                        _log.error('exceeded maximum # of bytes (%s) to receive' % max_bytes)
                                        return (0, rxd)
                # nothing there, wait a slice
                else:
                        if len(rxd) >= max_bytes:
                                _log.error('exceeded maximum # of bytes to receive')
                                return (0, rxd)
                        time.sleep(float(slice) / 1000)

        # hm, waited for aTimeout but expected string not received
        _log.warning('wait for [%s] timed out after %s ms', aString, aTimeout)
        _log.debug(rxd)
        return (0, rxd)
#--------------------------------------------------------
def wait_for_data(aDrv = None, aTimeout = 2500):
        """Wait for any incoming with timeout.

        - timeout in milliseconds, please
        """
        if aDrv is None:
                _log.error("Need source for incoming data !")
                return 0

        loop = 0
        slice = 100
        # how many loops ?
        max_loops = abs(aTimeout / slice)
        # wait for data
        while loop < max_loops:
                # nothing there, wait a slice
                if aDrv.inWaiting() == 0:
                        loop += 1
                        time.sleep(float(slice) / 1000)
                else:
                        return 1

        # hm, waited for aTimeout but expected string not received
        _log.warning('Timed out after %s ms while waiting for data.' % aTimeout)
        return 0