file read : feature or bug ?

Asbuilt Easynet ASBUILT at easynet.be
Tue Apr 15 18:10:17 CEST 2003


Hello,

I have a problem to use the read function that seems read more than
requested
as you can see in this sample demo.

Thanks

Jef

# This is a program to read a file in a reverse order by 3 characters block
# the demo.log file is 2 characters per line in windows so ended with CRLF
# 01
# 02
# 03
# 04
#
# we can see it like 01__02__03__04 where __ is CRLF
#
# PROBLEM :
# the program normaly should return
#   _04
#   03_
#   2__
#   __0
#   11
#
# BUT it returns
#   _04
#   03_
#   2_0     <-- From where is coming the 0 ?
#   _02     <-- From where is coming the 2 ?
#   11
#  (this is an extract from rgrep.py)

import string

l_bufsize = 3
l_file    = open("demo.log")
l_file.seek(0, 2)
l_pos      = l_file.tell()

while l_pos > 0:
  l_size = min(l_pos, l_bufsize)
  l_pos  = l_pos - l_size
  l_file.seek(l_pos)
  l_buffer = l_file.read(l_size)
  print "l_buffer = " + l_buffer + "[" + str(len(l_buffer)) +"]"

  l_lines = string.split(l_buffer, "x")
  print "Split = " + str(l_lines)
  del l_buffer






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