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1
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# I/O
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2
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3
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class StreamIter:
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4
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'''Iterates over the lines in a stream.
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5
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Unlike stream.__iter__(), doesn't wait for EOF to start returning lines.
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6
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Offers curr() method.
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7
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Forwards close() to the underlying stream.
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8
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'''
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def __init__(self, stream):
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10
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self.stream = stream
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11
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self.line = None
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12
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13
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def __iter__(self): return self
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14
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15
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def curr(self):
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16
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if self.line == None: self.line = self.stream.readline()
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if self.line == '': raise StopIteration
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18
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return self.line
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19
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20
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def next(self):
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21
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line = self.curr()
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22
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self.line = None
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23
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return line
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24
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25
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def close(self): self.stream.close()
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26
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27
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class TracedOutputStream:
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28
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'''Wraps an output stream, running a trace function on each string written
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29
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'''
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30
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def __init__(self, trace, stream):
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31
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self.trace = trace
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32
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self.stream = stream
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33
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34
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def write(self, str_):
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35
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self.trace(str_)
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36
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return self.stream.write(str_)
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37
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38
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class LineCountOutputStream(TracedOutputStream):
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39
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'''Wraps an output stream, making the current line number available.
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40
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Lines start counting from 1.'''
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41
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def __init__(self, stream):
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42
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self.line_num = 1
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43
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def trace(str_): self.line_num += str_.count('\n')
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44
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TracedOutputStream.__init__(self, trace, stream)
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