1 files changed, 113 insertions, 0 deletions
diff --git a/portato/eix.py b/portato/eix.py
new file mode 100644
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+++ b/portato/eix.py
@@ -0,0 +1,113 @@
+# -*- 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.")