pyetherpix

begin of config file parsing
Stefan Schuermans

Stefan Schuermans commited on 2017-05-25 22:18:34
Showing 7 changed files, with 223 additions and 0 deletions.

.gitignore
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+*.pyc
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+/dist/
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+/*.egg-info
pyetherpix/__init__.py
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+from display import Display
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+from msg import Msg, MsgDef
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+from parse import _parse_addr, _parse_two_nos
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+
pyetherpix/display.py
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+import msg
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+import parse
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+
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+
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+class Display(object):
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+
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+    def __init__(self, config_file, msg_obj=None):
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+        """create a new EtherPix display
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+           config_file: name of config file to read
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+           msg_obj: message callback object or None"""
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+        self._msg = msg_obj
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+        if self._msg is None: # use default message callback if none given
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+            self._msg = msg.MsgDef()
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+        # default settings
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+        self._bind_addr = ("0.0.0.0", 0) # local network address to bind to
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+        self._size = (0, 0) # size of display
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+        # read config file
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+        if not self._proc_config_file(config_file):
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+            raise Exception("error(s) while reading config file")
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+
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+    def _proc_config_file(self, config_file):
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+        """process config file
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+           config_file: name of config file to read
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+           returns True on success, False on error"""
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+        self._msg.msg(msg.Msg.INFO, "using config file \"%s\"" % config_file)
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+        # process all lines in config file
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+        okay = True
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+        try:
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+            with open(config_file, "r") as cfile:
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+                lineno = 1
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+                for line in cfile:
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+                   if not self._proc_config_line(line, lineno):
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+                       okay = False
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+                   lineno += 1
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+        except (IOError, OSError) as e:
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+            self._msg.msg(msg.Msg.ERR, str(e))
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+            okay = False
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+        return okay
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+
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+    def _proc_config_line(self, line, lineno):
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+        """process line from config file
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+           line: line read from config file
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+           lineno: line number
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+           returns True on success, False on error"""
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+        # parse config file line "setting = value # comment"
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+        line_no_comment = line.split("#", 1)[0].strip()
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+        if line_no_comment == "":
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+            return True # ignore empty lines
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+        else:
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+            fields = line_no_comment.split("=", 1)
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+            if len(fields) < 2:
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+                self._msg.msg(msg.Msg.WARN,
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+                              "invalid line %u in config file, ignored"
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+                              % lineno)
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+                return True
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+            else:
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+                setting = fields[0].strip()
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+                value = fields[1].strip()
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+                return self._proc_config_setting(setting, value, lineno)
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+
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+    def _proc_config_setting(self, setting, value, lineno):
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+        """process setting from config file
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+           setting: name of setting
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+           value: value of setting
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+           returns True on success, False on error"""
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+        # replace all whitespace sequences in setting with single spaces
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+        setting = " ".join(setting.split())
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+        # process setting
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+        if setting == "bindAddr":
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+            addr = parse._parse_addr(value)
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+            if addr is None:
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+                self._msg.msg(msg.Msg.ERR,
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+                              "invalid address \"%s\" for \"bindAddr\""
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+                              " in line %u in config file"
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+                              % (value, lineno))
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+                return False
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+            else:
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+                self._bind_addr = addr
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+                self._msg.msg(msg.Msg.INFO,
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+                              "bind address \"%s:%u\"" % (addr[0], addr[1]))
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+                return True
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+        elif setting == "size":
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+            size = parse._parse_two_nos(value)
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+            if size is None:
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+                self._msg.msg(msg.Msg.ERR,
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+                              "invalid address \"%s\" for \"size\""
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+                              " in line %u in config file"
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+                              % (value, lineno))
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+                return False
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+            else:
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+                self._size = size
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+                return True
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+        elif setting.startswith("distributor "):
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+            return True # TODO
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+        elif setting.startswith("distributorAddr "):
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+            return True # TODO
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+        elif setting.startswith("mapping "):
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+            return True # TODO
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+        elif setting.startswith("output "):
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+            return True # TODO
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+        else:
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+            self._msg.msg(msg.Msg.WARN,
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+                          "unknown setting \"%s\" in line %u in config file,"
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+                          " ignored" % (setting, lineno))
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+            return True
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+
pyetherpix/examples/blink.py
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+#! /usr/bin/env python
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+
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+import sys
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+import pyetherpix
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+
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+
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+def main(argv):
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+    if len(argv) < 2:
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+      print >>sys.stderr, "usage: %s <config.etp>" % argv[0]
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+      return 2
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+    config_file = argv[1]
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+    pyetherpix.Display(config_file)
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+    return 0
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+
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+
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+if __name__ == "__main__":
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+  sys.exit(main(sys.argv))
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+
pyetherpix/msg.py
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+import sys
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+
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+
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+class Msg(object):
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+
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+    ERR = 1
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+    WARN = 2
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+    INFO = 3
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+
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+    def __init__(self):
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+        """interface for message callback object"""
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+
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+    def msg(self, level, text):
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+        """message is delivered
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+           level: ERR for errors, WARN for warnings, INFO for information
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+           text: message text"""
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+        raise NotImplementedError("Msg.msg is not implemented")
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+
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+
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+class MsgDef(Msg):
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+
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+    def __init__(self, level=Msg.INFO):
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+        """default message callback implementation
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+           level: level of messages to output"""
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+        Msg.__init__(self)
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+        self._level = level
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+
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+    def msg(self, level, text):
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+        """message is delivered
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+           level: ERR for errors, WARN for warnings, INFO for information
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+           text: message text"""
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+        if level == Msg.ERR:
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+          prefix = "error"
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+        elif level == Msg.WARN:
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+          prefix = "warning"
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+        elif level == Msg.INFO:
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+          prefix = "info"
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+        else:
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+          prefix = "unknown"
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+        if level <= self._level:
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+          print >>sys.stderr, prefix + ": " + text
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+
pyetherpix/parse.py
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+def _parse_addr(addr_str):
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+    """parse an IPv4 address, e.g. \"1.2.3.4:567\",
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+       return tuple of IP and port, e.g. ("1.2.3.4", 567), None on error"""
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+    fields = addr_str.split(":")
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+    if len(fields) > 2:
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+        return None
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+    ip = fields[0]
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+    port = fields[1]
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+    if len(ip.split(".")) != 4:
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+        return None
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+    try:
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+        port = int(port)
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+    except:
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+        return None
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+    if port < 0 or port > 65535:
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+        return None
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+    return (ip, port)
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+
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+def _parse_two_nos(txt):
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+    """parse two comma separated decimal unsigned integers from string,
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+       e.g. \"12,34\", return tuple of two numbers, e.g. (12, 34),
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+       None on error"""
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+    fields = txt.strip().split()
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+    if len(fields) > 1:
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+        return None
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+    fields = fields[0].split(",")
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+    if len(fields) != 2:
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+        return None
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+    try:
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+        no1 = int(fields[0])
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+        no2 = int(fields[1])
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+    except:
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+        return None
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+    if no1 < 0 or no2 < 0:
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+        return None
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+    return (no1, no2)
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+
setup.py
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+from setuptools import setup
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+
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+setup(name='pyetherpix',
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+      version='0.1',
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+      description='python implementation of EtherPix output library',
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+      url='https://git.blinkenarea.org?p=libetherpix',
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+      author='Stefan Schuermans',
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+      author_email='stefan@schuermans.info',
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+      license='LGPLv3',
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+      packages=['pyetherpix'],
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+      install_requires=[],
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+      zip_safe=False)
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+
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