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+# -*- coding: utf-8 -*-
+#
+# File: portato/eix.py
+# This file is part of the Portato-Project, a graphical portage-frontend.
+#
+# Copyright (C) 2006-2009 René 'Necoro' Neumann
+# This is free software. You may redistribute copies of it under the terms of
+# the GNU General Public License version 2.
+# There is NO WARRANTY, to the extent permitted by law.
+#
+# Written by René 'Necoro' Neumann <necoro@necoro.net>
+
+from __future__ import absolute_import, with_statement
+
+import struct
+from functools import wraps
+
+from .helper import debug
+
+class EixError (Exception):
+ message = "Unknown error."
+
+ def __str__ (self):
+ return self.message
+
+class EndOfFileException (EixError):
+
+ def __init__ (self, filename):
+ self.message = "End of file reached though it was not expected: '%s'" % filename
+
+class EixReaderClosed (EixError):
+ message = "EixReader is already closed."
+
+class UnsupportedVersionError (EixError):
+
+ def __init__ (self, version):
+ self.message = "Version '%s' is not supported." % version
+
+class EixReader (object):
+ supported_versions = (28, )
+
+ def __init__ (self, filename):
+ self.filename = filename
+ self.file = open(filename, "r")
+ self.closed = 0
+
+ try:
+ self.version = self.get_number()
+
+ if self.version not in self.supported_versions:
+ raise UnsupportedVersionError(self.version)
+
+ debug("Started EixReader for version %s.", self.version)
+ except:
+ self.close()
+ raise
+
+ def check_closed (f):
+ @wraps(f)
+ def wrapper (self, *args, **kwargs):
+ if self.closed:
+ raise EixReaderClosed
+
+ return f(self, *args, **kwargs)
+ return wrapper
+
+ @check_closed
+ def get_number (self):
+ n = self._get_bytes(1)
+
+ if n < 0xFF:
+ value = n
+ else:
+ count = 0
+
+ while (n == 0xFF):
+ count += 1
+ n = self._get_bytes(1)
+
+ if n == 0:
+ n = 0xFF # 0xFF is encoded as 0xFF 0x00
+ count -= 1
+
+ value = n << (count*8)
+
+ if count > 0:
+ rest = self._get_bytes(count, expect_list = True)
+
+ for i, r in enumerate(rest):
+ value += r << ((count - i - 1)*8)
+
+ return value
+
+ def _get_bytes (self, length, expect_list = False):
+ s = self.file.read(length)
+
+ if len(s) != length:
+ raise EndOfFileException, self.filename
+
+ if length == 1 and not expect_list:
+ return ord(s) # is faster than unpack and we have a scalar
+ else:
+ return struct.unpack("%sB" % length, s)
+
+ @check_closed
+ def close (self):
+ if self.closed:
+ raise EixReaderClosed
+
+ self.file.close()
+ self.closed = 1
+
+ debug("EixReader closed.")