Jim Paris
7dfa288270
git-svn-id: https://bucket.mit.edu/svn/nilm/nilmdb@10709 ddd99763-3ecb-0310-9145-efcb8ce7c51f
109 lines
3.3 KiB
Python
109 lines
3.3 KiB
Python
"""File-like objects that add timestamps to the input lines"""
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from __future__ import absolute_import
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from nilmdb.printf import *
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import time
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import os
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import datetime_tz
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class Timestamper(object):
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"""A file-like object that adds timestamps to lines of an input file."""
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def __init__(self, file, ts_iter):
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"""file: filename, or another file-like object
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ts_iter: iterator that returns a timestamp string for
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each line of the file"""
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if isinstance(file, basestring):
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self.file = open(file, "r")
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else:
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self.file = file
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self.ts_iter = ts_iter
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def close(self):
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self.file.close()
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def readline(self, *args):
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while True:
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line = self.file.readline(*args)
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if not line:
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return ""
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if line[0] == '#':
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continue
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break
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try:
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return self.ts_iter.next() + line
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except StopIteration:
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return ""
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def readlines(self, size = None):
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out = ""
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while True:
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line = self.readline()
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out += line
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if not line or (size and len(out) >= size):
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break
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return out
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def __iter__(self):
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return self
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def next(self):
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result = self.readline()
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if not result:
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raise StopIteration
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return result
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class TimestamperRate(Timestamper):
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"""Timestamper that uses a start time and a fixed rate"""
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def __init__(self, file, start, rate, end = None):
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"""
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file: file name or object
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start: Unix timestamp for the first value
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rate: 1/rate is added to the timestamp for each line
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end: If specified, raise StopIteration before outputting a value
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greater than this."""
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def iterator(start, rate, end):
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n = 0
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rate = float(rate)
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while True:
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now = start + n / rate
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if end and now >= end:
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raise StopIteration
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yield sprintf("%.6f ", start + n / rate)
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n += 1
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# Handle case where we're passed a datetime or datetime_tz object
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if "totimestamp" in dir(start):
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start = start.totimestamp()
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Timestamper.__init__(self, file, iterator(start, rate, end))
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self.start = start
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self.rate = rate
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def __str__(self):
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start = datetime_tz.datetime_tz.fromtimestamp(self.start)
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start = start.strftime("%a, %d %b %Y %H:%M:%S %Z")
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return sprintf("TimestamperRate(..., start=\"%s\", rate=%g)",
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str(start), self.rate)
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class TimestamperNow(Timestamper):
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"""Timestamper that uses current time"""
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def __init__(self, file):
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def iterator():
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while True:
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now = datetime_tz.datetime_tz.utcnow().totimestamp()
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yield sprintf("%.6f ", now)
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Timestamper.__init__(self, file, iterator())
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def __str__(self):
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return "TimestamperNow(...)"
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class TimestamperNull(Timestamper):
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"""Timestamper that adds nothing to each line"""
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def __init__(self, file):
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def iterator():
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while True:
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yield ""
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Timestamper.__init__(self, file, iterator())
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def __str__(self):
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return "TimestamperNull(...)"
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