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#!/usr/bin/env python

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# -*- coding: utf-8 -*-

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# See COPYING file for copyrights details.

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import hashlib

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from runtime import PlcStatus

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class ConnectorBase(object):

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    chuncksize = 0xfff # 4KB

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    PLCObjDefaults = {

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        "StartPLC": False,

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        "GetTraceVariables": (PlcStatus.Broken, None),

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        "GetPLCstatus": (PlcStatus.Broken, None),

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        "RemoteExec": (-1, "RemoteExec script failed!"),

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        "GetVersions": "*** Unknown ***"

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    }

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    def BlobFromFile(self, filepath, seed):

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        s = hashlib.new('md5')

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        s.update(seed.encode())

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        blobID = self.SeedBlob(seed.encode())

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        with open(filepath, "rb") as f:

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            while blobID == s.digest():

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                chunk = f.read(self.chuncksize)

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                if len(chunk) == 0:

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                    return blobID

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                blobID = self.AppendChunkToBlob(chunk, blobID)

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                s.update(chunk)

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        raise IOError("Data corrupted during transfer or connection lost")