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# $Id$
#
# Copyright (C) 1997 Klee Dienes <klee@mit.edu>
#
# This program is free software; you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation; either version 2 of the License, or
# (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program; if not, write to the Free Software
# Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
class subfile:
def __init__ (self, f, offset, length = -1):
self.f = f
self.f.seek (offset)
self.offset = offset
self.pos = 0
self.length = length
self.blocksize = 16 * 1024
def isatty (self):
return 0
def tell (self):
#print 'sfile: tell is %d' % self.pos
return self.pos
def seek (self, offset, mode = 0):
#print 'sfile: seeking from %d to %d' % (self.pos, offset)
if (mode == 0):
if (self.length < 0):
self.pos = offset
self.f.seek (self.pos + self.offset)
else:
if (offset > self.length):
raise IOError, 'seek past end of file'
self.pos = offset
self.f.seek (self.pos + self.offset)
if (mode == 1):
self.pos = self.pos + offset
self.f.seek (self.pos + self.offset)
elif (mode == 2):
if (length < 0):
self.f.seek (0, 2)
self.pos = self.f.tell () - self.offset
elif (length > self.length):
raise IOError, 'seek past end of file'
else:
self.seek (self.pos + self.length - self.offset)
def read (self, n = -1):
self.f.seek (self.offset + self.pos)
#print 'sfile: n: %d' % n
if ((n < 0) and (self.length >= 0)):
n = self.length - self.pos
if (self.length >= 0):
n = min (n, self.length - self.pos)
#print 'sfile: n: %d' % n
r = ''
while (n != 0):
op = self.f.tell ()
s = self.f.read (n)
#print 'sfile: read %d bytes from %d (%d in original)' % (len (s), self.pos, op)
self.pos = self.pos + len (s)
n = n - len (s)
if (s == ''):
break
r = r + s
#print 'returning: "%s"' % r
return r
def readline (self):
r = ''
while 1:
s = self.read (1)
if (s == ''):
return r
r = r + s
if (s == '\n'):
return r
def readlines (self):
r = []
while 1:
l = self.readline ()
if (l == ''):
return r
r.append (l)
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