Make it possible to override tags

Replace the "= object()" with a proper class and explanation


git-svn-id: svn+ssh://localhost/home/henryk/svn/cyberflex-shell/trunk@93 f711b948-2313-0410-aaa9-d29f33439f0b

TLV_utils.py

@@ -1,12 +1,28 @@
-import binascii, utils, sre
+import binascii, utils, sre, sys
 
-context_FCP = object()
-context_FMD = object()
-context_FCI = object()
-recurse = object()
-binary = object()
-number = object()
-ascii = object()
+class identifier:
+    """An identifier, because I'm too lazy to use quotes all over the place.
+    Instantiating an object of this type registers a name in the current scope, essentially
+    making each instantiation of this class equal to
+        foo = identifier("foo")
+    even when you only write
+        identifier("foo")
+    """
+    def __init__(self,name):
+        self.name = name
+        sys._getframe(1).f_locals[name] = self
+    def __str__(self):
+        return self.name
+    def __repr__(self):
+        return "identifier(%r)" % self.name
+
+identifier("context_FCP")
+identifier("context_FMD")
+identifier("context_FCI")
+identifier("recurse")
+identifier("binary")
+identifier("number")
+identifier("ascii")
 
 file_descriptor_byte_descriptions = [
     #mask  byte  no match match
@@ -241,7 +257,7 @@ def tlv_unpack(data):
     
     return ber_class, constructed, tag, length, value, rest
 
-def decode(data, context = None, level = 0):
+def decode(data, context = None, level = 0, tags=tags):
     result = []
     while len(data) > 0:
         if ord(data[0]) in (0x00, 0xFF):
@@ -263,7 +279,7 @@ def decode(data, context = None, level = 0):
         
         if interpretation[0] is recurse:
             current.append("\n")
-            current.append( decode(value, interpretation[2], level+1) )
+            current.append( decode(value, interpretation[2], level+1, tags=tags) )
         elif interpretation[0] is number:
             num = 0
             for i in value:

cards/__init__.py

@@ -55,6 +55,7 @@ class Cardmultiplexer:
     of the participating classes instead of overriding them."""
     
     MERGE_DICTS = ("APPLICATIONS", "COMMANDS", "STATUS_WORDS")
+    MERGE_DICTS_RECURSIVE = ("TLV_OBJECTS", )
     MERGE_LISTS = ()
     
     def __init__(self, classes, *args, **kwargs):
@@ -143,12 +144,29 @@ class Cardmultiplexer:
     def _merge_attributes(self):
         """Update the local copy of merged attributes."""
         
-        for attr in self.MERGE_DICTS:
+        for attr in self.MERGE_DICTS + self.MERGE_DICTS_RECURSIVE:
             tmpdict = {}
             have_one = False
             for cls in self._classes:
                 if hasattr(cls, attr):
-                    tmpdict.update( getattr(cls, attr) )
+                    if not attr in self.MERGE_DICTS_RECURSIVE:
+                        tmpdict.update( getattr(cls, attr) )
+                    else:
+                        def recurse(target, source):
+                            for (key, value) in source.items():
+                                if target.has_key(key):
+                                    if isinstance(value, dict) and isinstance(target[key], dict):
+                                        recurse( target[key], value )
+                                    elif isinstance(value, dict):
+                                        target[key] = dict(value)
+                                    else:
+                                        target[key] = value
+                                else:
+                                    if isinstance(value, dict):
+                                        target[key] = dict(value)
+                                    else:
+                                        target[key] = value
+                        recurse( tmpdict, getattr(cls, attr) )
                     have_one = True
             if have_one:
                 setattr(self, attr, tmpdict)

cards/generic_card.py

@@ -27,6 +27,8 @@ class Card:
         '6C??': "Bad value for LE, 0x%(SW2)02x is the correct value.",
         '63C?': lambda SW1,SW2: "The counter has reached the value '%i'" % (SW2%16)
     }
+    ## For the format of this dictionary of dictionaries see TLV_utils.tags
+    TLV_OBJECTS = {}
 
     def __init__(self, card = None, reader = None):
         if card is None:
@@ -61,7 +63,7 @@ class Card:
     
     def cmd_parsetlv(self):
         "Decode the TLV data in the last response"
-        print TLV_utils.decode(self.last_result.data)
+        print TLV_utils.decode(self.last_result.data, tags=self.TLV_OBJECTS)
     
     COMMANDS = {
         "reset": cmd_reset,

cards/iso_7816_4_card.py

@@ -36,7 +36,7 @@ class ISO_7816_4_Card(Card):
         
         if len(result.data) > 0:
             print utils.hexdump(result.data)
-            print TLV_utils.decode(result.data)
+            print TLV_utils.decode(result.data,tags=self.TLV_OBJECTS)
     
     def open_file(self, fid):
         "Open an EF under the current DF"
@@ -49,7 +49,7 @@ class ISO_7816_4_Card(Card):
         result = self.open_file(fid)
         if len(result.data) > 0:
             print utils.hexdump(result.data)
-            print TLV_utils.decode(result.data)
+            print TLV_utils.decode(result.data,tags=self.TLV_OBJECTS)
 
     def read_binary_file(self, offset = 0):
         """Read from the currently selected EF.
@@ -93,7 +93,7 @@ class ISO_7816_4_Card(Card):
         result = self.select_file(p1, p2, fid)
         if len(result.data) > 0:
             print utils.hexdump(result.data)
-            print TLV_utils.decode(result.data)
+            print TLV_utils.decode(result.data,tags=self.TLV_OBJECTS)
     
     ATRS = list(Card.ATRS)
     ATRS.extend( [
@@ -162,3 +162,5 @@ class ISO_7816_4_Card(Card):
         "6A87": "Wrong parameter(s) P1-P2, Lc inconsistent with P1-P2",
         "6A88": "Wrong parameter(s) P1-P2, Referenced data not found",
     } )
+    
+    TLV_OBJECTS = TLV_utils.tags