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Viewing changes to Tools/scripts/rgrep.py

  • Committer: Bazaar Package Importer
  • Author(s): Matthias Klose
  • Date: 2009-03-23 00:01:27 UTC
  • Revision ID: james.westby@ubuntu.com-20090323000127-5fstfxju4ufrhthq
Tags: upstream-3.1~a1+20090322
Import upstream version 3.1~a1+20090322

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Tools/scripts/rgrep.py
 
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#! /usr/bin/env python
 
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"""Reverse grep.
 
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Usage: rgrep [-i] pattern file
 
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"""
 
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import sys
 
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import re
 
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import getopt
 
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def main():
 
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    bufsize = 64*1024
 
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    reflags = 0
 
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    opts, args = getopt.getopt(sys.argv[1:], "i")
 
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    for o, a in opts:
 
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        if o == '-i':
 
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            reflags = reflags | re.IGNORECASE
 
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    if len(args) < 2:
 
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        usage("not enough arguments")
 
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    if len(args) > 2:
 
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        usage("exactly one file argument required")
 
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    pattern, filename = args
 
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    try:
 
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        prog = re.compile(pattern, reflags)
 
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    except re.error as msg:
 
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        usage("error in regular expression: %s" % str(msg))
 
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    try:
 
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        f = open(filename)
 
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    except IOError as msg:
 
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        usage("can't open %s: %s" % (repr(filename), str(msg)), 1)
 
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    f.seek(0, 2)
 
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    pos = f.tell()
 
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    leftover = None
 
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    while pos > 0:
 
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        size = min(pos, bufsize)
 
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        pos = pos - size
 
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        f.seek(pos)
 
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        buffer = f.read(size)
 
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        lines = buffer.split("\n")
 
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        del buffer
 
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        if leftover is None:
 
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            if not lines[-1]:
 
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                del lines[-1]
 
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        else:
 
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            lines[-1] = lines[-1] + leftover
 
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        if pos > 0:
 
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            leftover = lines[0]
 
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            del lines[0]
 
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        else:
 
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            leftover = None
 
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        lines.reverse()
 
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        for line in lines:
 
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            if prog.search(line):
 
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                print(line)
 
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def usage(msg, code=2):
 
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    sys.stdout = sys.stderr
 
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    print(msg)
 
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    print(__doc__)
 
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    sys.exit(code)
 
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if __name__ == '__main__':
 
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    main()