from __future__ import generators
"""Provides a class called LineIterator that iterates over every line in a list of files.
Performing the basic functionality as fileinput module in the standard
library (which mimics Perl's <> operator). Basically acts as a simple
and methodical way to iterate over every line in a list of files. If
not files are specified at instance creation, then sys.argv[1:] is used.
If that is empty, then sys.stdin is used. sys.stdin can be specified in
the list of files by listing '-' as a file.
Lacking functionality, compared to the fileinput module, is in-place
editing and subsequently backup. The module functions that are included
in fileinput are left out here for space concerns. readline() has also
been left out since the generator can just have its .next() method called.
Dedicated to my grandmother, Mary Alice Renshaw (1911/12/13-2002/01/13).
"""
import sys
__author__ = 'Brett Cannon'
__email__ = 'drifty@bigfoot.com'
__version__ = '1.0'
class LineIterator(object):
"""Basic reimplementation of fileinput.FileInput using generators.
Passed in files are iterated over (file by file, line by line), and
returned by the iterator. Use of sys.stdin is specified by '-'.
if no files are specified, sys.argv[1:] is used. If that is empty,
sys.stdin is used.
Flags values (| values together; set by various methods):
1 :: Close current file
2 :: End generator (thus 3 closes the current file and ends the
generator)
"""
def __init__(self, file_list=sys.argv[1:]):
"""Set all instance variables.
If no files are specified (either passed in or from sys.argv[1:]),
then sys.stdin is then used by making the only file '-'.
"""
if file_list:
if isinstance(file_list,str):
self.__file_list = [file_list]
else:
self.__file_list = file_list
else:
self.__file_list = list('-')
self.__current_file=''
self.__relative_cnt = 0
self.__absolute_cnt = 0
self.__flags = 0
def nextfile(self):
"""Starts looping over next file."""
self.__flags = 1
def close(self):
"""Ends the generator.
Does this by setting __flag to both close the current file and
end the generator.
"""
self.__flags = 3
def filename(self):
"""Returns name of current file."""
if self.__current_file == '-':
return 'sys.stdin'
else:
return self.__current_file
def lineno(self):
"""Returns accumulative line total thus far."""
return self.__absolute_cnt
def filelineno(self):
"""Returns line total for the current file thus far."""
return self.__relative_cnt
def __iter__(self):
"""Generator for looping over every line in the files in self.files.
If __flag is set to &2, then end the generator. Otherwise check if
'-' (read: sys.stdin) is the next file. Set __relative_cnt to 0 and
start iterating.
If __flag is set to &1, close the current file and break the loop.
Else see if the file name equals the current file name. If not,
change it. Then increment both __relative_cnt and __absolute_cnt.
Finally, yield the line.
"""
for file_location in self.__file_list:
if self.__flags & 2:
return
if file_location == '-':
FILE = sys.stdin
else:
FILE = open(file_location,'r')
self.__relative_cnt = 0
for line in FILE:
if self.__flags & 1:
FILE.close()
break
if file_location != self.__current_file:
self.__current_file = file_location
self.__relative_cnt += 1
self.__absolute_cnt += 1
yield line
else: FILE.close()
