run.py

import argparse
import sys
import os
from math import floor, ceil
import logging
import logging.handlers

import alg_main

parser = argparse.ArgumentParser()
parser.add_argument('-A', type=float, help='approximation parameter "A"')
parser.add_argument('-e',
                    type=float,
                    metavar='EPSILON',
                    help='approximation parameter "epsilon"')
parser.add_argument('-i',
                    '--infile',
                    metavar='FILE',
                    nargs='?',
                    help='input file (stdin used if absent)')
parser.add_argument('-L',
                    '--log',
                    action='store_true',
                    help='verbose logging into logfile')
parser.add_argument('--logcomment',
                    metavar='TEXT',
                    default='',
                    nargs='?',
                    help='text tag to include in logs')
parser.add_argument('--nologheader',
                    action='store_true',
                    help='omit column headers in logs')


def go(f, A, eps, logheader=True, logcomment=''):
    n = os.fstat(f.fileno()).st_size
    fd, fn = os.path.split(f.name)

    print()
    text_log.info('size of {} is {:,} bytes'.format(fn, n))
    est = alg_main.alg1(f, A, eps, logheader=logheader, logcomment=logcomment)
    est = round(est)

    text_log.info('estimate of length of optimal parsing: {:,} ({:%})'.format(
        est, est / n))
    low = ceil((est - eps * n) / A)
    high = floor((est + eps * n) * A)
    text_log.info('optimal parsing between {:,} and {:,}'.format(low, high))


text_log = logging.getLogger('estcompr.text')
data_log = logging.getLogger('estcompr.data')

if __name__ == '__main__':

    args = parser.parse_args()

    # logging {{{
    plain_format = logging.Formatter('%(message)s')
    detail_format = logging.Formatter('%(asctime)s %(levelname)s: %(message)s')
    to_screen = logging.StreamHandler()
    to_screen.setFormatter(plain_format)
    if args.log:
        text_log.setLevel('DEBUG')
        to_text_files = logging.handlers.RotatingFileHandler(
            filename='estcompr.log', maxBytes=10 * 1024 * 1024, backupCount=2)
        to_text_files.setFormatter(detail_format)
        text_log.addHandler(to_text_files)

        data_log.setLevel('DEBUG')
        to_data_files = logging.handlers.RotatingFileHandler(
            filename='estcompr_data.log',
            maxBytes=10 * 1024 * 1024,
            backupCount=2)
        to_data_files.setFormatter(plain_format)
        data_log.addHandler(to_data_files)

        to_screen.setLevel('INFO')
        text_log.addHandler(to_screen)
    else:
        text_log.setLevel('INFO')
        text_log.addHandler(to_screen)
    # }}}

    A, eps = args.A, args.e

    # stdin default
    if not args.infile:
        go(sys.stdin, A, eps)
    else:
        assert os.path.isfile(args.infile)
        with open(args.infile, 'rb') as f:
            go(f,
               A,
               eps,
               logheader=(not args.nologheader),
               logcomment=args.logcomment)