]> Cypherpunks.ru repositories - pyderasn.git/blobdiff - pyderasn.py
Substitute class name in exception
[pyderasn.git] / pyderasn.py
index dbe706640e02878c438bafe8799efdb07d58bba3..15ca386b89894c7c4278fc2914f5ca9c3b44e199 100755 (executable)
@@ -20,7 +20,7 @@
 """Python ASN.1 DER/BER codec with abstract structures
 
 This library allows you to marshal various structures in ASN.1 DER
-format, unmarshal them in BER/CER/DER ones.
+format, unmarshal BER/CER/DER ones.
 
     >>> i = Integer(123)
     >>> raw = i.encode()
@@ -901,6 +901,12 @@ encoding mode.
 If you want to encode to the memory, then you can use convenient
 :py:func:`pyderasn.encode2pass` helper.
 
+.. _browser:
+
+ASN.1 browser
+-------------
+.. autofunction:: pyderasn.browse
+
 Base Obj
 --------
 .. autoclass:: pyderasn.Obj
@@ -917,7 +923,7 @@ _______
 Integer
 _______
 .. autoclass:: pyderasn.Integer
-   :members: __init__, named
+   :members: __init__, named, tohex
 
 BitString
 _________
@@ -956,6 +962,14 @@ _______________
 .. autoclass:: pyderasn.PrintableString
    :members: __init__, allow_asterisk, allow_ampersand
 
+IA5String
+_________
+.. autoclass:: pyderasn.IA5String
+
+VisibleString
+_____________
+.. autoclass:: pyderasn.VisibleString
+
 UTCTime
 _______
 .. autoclass:: pyderasn.UTCTime
@@ -1011,12 +1025,14 @@ Various
 
 .. autofunction:: pyderasn.abs_decode_path
 .. autofunction:: pyderasn.agg_octet_string
+.. autofunction:: pyderasn.ascii_visualize
 .. autofunction:: pyderasn.colonize_hex
 .. autofunction:: pyderasn.encode2pass
 .. autofunction:: pyderasn.encode_cer
 .. autofunction:: pyderasn.file_mmaped
 .. autofunction:: pyderasn.hexenc
 .. autofunction:: pyderasn.hexdec
+.. autofunction:: pyderasn.hexdump
 .. autofunction:: pyderasn.tag_encode
 .. autofunction:: pyderasn.tag_decode
 .. autofunction:: pyderasn.tag_ctxp
@@ -1185,7 +1201,7 @@ except ImportError:  # pragma: no cover
     def colored(what, *args, **kwargs):
         return what
 
-__version__ = "7.3"
+__version__ = "7.6"
 
 __all__ = (
     "agg_octet_string",
@@ -1279,11 +1295,13 @@ def file_mmaped(fd):
     """
     return memoryview(mmap(fd.fileno(), 0, prot=PROT_READ))
 
+
 def pureint(value):
     if not set(value) <= DECIMALS:
         raise ValueError("non-pure integer")
     return int(value)
 
+
 def fractions2float(fractions_raw):
     pureint(fractions_raw)
     return float("0." + fractions_raw)
@@ -1296,7 +1314,7 @@ def get_def_by_path(defines_by_path, sub_decode_path):
         if len(path) != len(sub_decode_path):
             continue
         for p1, p2 in zip(path, sub_decode_path):
-            if (not p1 is any) and (p1 != p2):
+            if (p1 is not any) and (p1 != p2):
                 break
         else:
             return define
@@ -1955,7 +1973,7 @@ class Obj(object):
                     yield None
                     return
                 _decode_path, obj, tail = result
-                if not _decode_path is decode_path:
+                if _decode_path is not decode_path:
                     yield result
         else:
             try:
@@ -1997,7 +2015,7 @@ class Obj(object):
                         yield None
                         return
                     _decode_path, obj, tail = result
-                    if not _decode_path is decode_path:
+                    if _decode_path is not decode_path:
                         yield result
                 eoc_expected, tail = tail[:EOC_LEN], tail[EOC_LEN:]
                 if eoc_expected.tobytes() != EOC:
@@ -2036,7 +2054,7 @@ class Obj(object):
                         yield None
                         return
                     _decode_path, obj, tail = result
-                    if not _decode_path is decode_path:
+                    if _decode_path is not decode_path:
                         yield result
                 if obj.tlvlen < l and not ctx.get("allow_expl_oob", False):
                     raise DecodeError(
@@ -2300,6 +2318,15 @@ def colonize_hex(hexed):
     return ":".join(hexed[i:i + 2] for i in six_xrange(0, len(hexed), 2))
 
 
+def find_oid_name(asn1_type_name, oid_maps, value):
+    if len(oid_maps) > 0 and asn1_type_name == ObjectIdentifier.asn1_type_name:
+        for oid_map in oid_maps:
+            oid_name = oid_map.get(value)
+            if oid_name is not None:
+                return oid_name
+    return None
+
+
 def pp_console_row(
         pp,
         oid_maps=(),
@@ -2323,9 +2350,7 @@ def pp_console_row(
         col += _colourize("B", "red", with_colours) if pp.bered else " "
         cols.append(col)
         col = "[%d,%d,%4d]%s" % (
-            pp.tlen,
-            pp.llen,
-            pp.vlen,
+            pp.tlen, pp.llen, pp.vlen,
             LENINDEF_PP_CHAR if pp.lenindef else " "
         )
         col = _colourize(col, "green", with_colours, ())
@@ -2337,19 +2362,11 @@ def pp_console_row(
         if isinstance(ent, DecodePathDefBy):
             cols.append(_colourize("DEFINED BY", "red", with_colours, ("reverse",)))
             value = str(ent.defined_by)
-            oid_name = None
-            if (
-                    len(oid_maps) > 0 and
-                    ent.defined_by.asn1_type_name ==
-                    ObjectIdentifier.asn1_type_name
-            ):
-                for oid_map in oid_maps:
-                    oid_name = oid_map.get(value)
-                    if oid_name is not None:
-                        cols.append(_colourize("%s:" % oid_name, "green", with_colours))
-                        break
+            oid_name = find_oid_name(ent.defined_by.asn1_type_name, oid_maps, value)
             if oid_name is None:
                 cols.append(_colourize("%s:" % value, "white", with_colours, ("reverse",)))
+            else:
+                cols.append(_colourize("%s:" % oid_name, "green", with_colours))
         else:
             cols.append(_colourize("%s:" % ent, "yellow", with_colours, ("reverse",)))
     if pp.expl is not None:
@@ -2368,23 +2385,12 @@ def pp_console_row(
     if pp.value is not None:
         value = pp.value
         cols.append(_colourize(value, "white", with_colours, ("reverse",)))
-        if (
-                len(oid_maps) > 0 and
-                pp.asn1_type_name == ObjectIdentifier.asn1_type_name
-        ):
-            for oid_map in oid_maps:
-                oid_name = oid_map.get(value)
-                if oid_name is not None:
-                    cols.append(_colourize("(%s)" % oid_name, "green", with_colours))
-                    break
+        oid_name = find_oid_name(pp.asn1_type_name, oid_maps, pp.value)
+        if oid_name is not None:
+            cols.append(_colourize("(%s)" % oid_name, "green", with_colours))
         if pp.asn1_type_name == Integer.asn1_type_name:
-            hex_repr = hex(int(pp.obj._value))[2:].upper()
-            if len(hex_repr) % 2 != 0:
-                hex_repr = "0" + hex_repr
             cols.append(_colourize(
-                "(%s)" % colonize_hex(hex_repr),
-                "green",
-                with_colours,
+                "(%s)" % colonize_hex(pp.obj.tohex()), "green", with_colours,
             ))
     if with_blob:
         if pp.blob.__class__ == binary_type:
@@ -2430,7 +2436,7 @@ def pprint(
     """Pretty print object
 
     :param Obj obj: object you want to pretty print
-    :param oid_maps: list of ``str(OID) <-> human readable string`` dictionary.
+    :param oid_maps: list of ``str(OID) <-> human readable string`` dictionaries.
                      Its human readable form is printed when OID is met
     :param big_blobs: if large binary objects are met (like OctetString
                       values), do we need to print them too, on separate
@@ -2851,6 +2857,16 @@ class Integer(Obj):
         self._assert_ready()
         return int(self._value)
 
+    def tohex(self):
+        """Hexadecimal representation
+
+        Use :py:func:`pyderasn.colonize_hex` for colonizing it.
+        """
+        hex_repr = hex(int(self))[2:].upper()
+        if len(hex_repr) % 2 != 0:
+            hex_repr = "0" + hex_repr
+        return hex_repr
+
     def __hash__(self):
         self._assert_ready()
         return hash(b"".join((
@@ -2942,7 +2958,6 @@ class Integer(Obj):
                 else:
                     break
         return octets
-        return b"".join((self.tag, len_encode(len(octets)), octets))
 
     def _encode(self):
         octets = self._encode_payload()
@@ -3368,7 +3383,7 @@ class BitString(Obj):
                 int2byte(0),
                 octets[offset:offset + 999],
             )))
-        tail = octets[offset+999:]
+        tail = octets[offset + 999:]
         if len(tail) > 0:
             tail = int2byte((8 - bit_len % 8) % 8) + tail
             write_full(writer, b"".join((
@@ -3828,7 +3843,7 @@ class OctetString(Obj):
                 LEN1K,
                 octets[offset:offset + 1000],
             )))
-        tail = octets[offset+1000:]
+        tail = octets[offset + 1000:]
         if len(tail) > 0:
             write_full(writer, b"".join((
                 OctetString.tag_default,
@@ -4703,27 +4718,25 @@ class CommonString(OctetString):
        :header-rows: 1
 
        * - Class
-         - Text Encoding
+         - Text Encoding, validation
        * - :py:class:`pyderasn.UTF8String`
          - utf-8
        * - :py:class:`pyderasn.NumericString`
-         - ascii
+         - proper alphabet validation
        * - :py:class:`pyderasn.PrintableString`
-         - ascii
+         - proper alphabet validation
        * - :py:class:`pyderasn.TeletexString`
-         - ascii
+         - iso-8859-1
        * - :py:class:`pyderasn.T61String`
-         - ascii
+         - iso-8859-1
        * - :py:class:`pyderasn.VideotexString`
          - iso-8859-1
        * - :py:class:`pyderasn.IA5String`
-         - ascii
+         - proper alphabet validation
        * - :py:class:`pyderasn.GraphicString`
          - iso-8859-1
-       * - :py:class:`pyderasn.VisibleString`
-         - ascii
-       * - :py:class:`pyderasn.ISO646String`
-         - ascii
+       * - :py:class:`pyderasn.VisibleString`, :py:class:`pyderasn.ISO646String`
+         - proper alphabet validation
        * - :py:class:`pyderasn.GeneralString`
          - iso-8859-1
        * - :py:class:`pyderasn.UniversalString`
@@ -4831,6 +4844,12 @@ class AllowableCharsMixin(object):
             return self._allowable_chars
         return frozenset(six_unichr(c) for c in self._allowable_chars)
 
+    def _value_sanitize(self, value):
+        value = super(AllowableCharsMixin, self)._value_sanitize(value)
+        if not frozenset(value) <= self._allowable_chars:
+            raise DecodeError("non satisfying alphabet value")
+        return value
+
 
 class NumericString(AllowableCharsMixin, CommonString):
     """Numeric string
@@ -4847,12 +4866,6 @@ class NumericString(AllowableCharsMixin, CommonString):
     asn1_type_name = "NumericString"
     _allowable_chars = frozenset(digits.encode("ascii") + b" ")
 
-    def _value_sanitize(self, value):
-        value = super(NumericString, self)._value_sanitize(value)
-        if not frozenset(value) <= self._allowable_chars:
-            raise DecodeError("non-numeric value")
-        return value
-
 
 PrintableStringState = namedtuple(
     "PrintableStringState",
@@ -4920,12 +4933,6 @@ class PrintableString(AllowableCharsMixin, CommonString):
         """
         return self._ampersand <= self._allowable_chars
 
-    def _value_sanitize(self, value):
-        value = super(PrintableString, self)._value_sanitize(value)
-        if not frozenset(value) <= self._allowable_chars:
-            raise DecodeError("non-printable value")
-        return value
-
     def __getstate__(self):
         return PrintableStringState(
             *super(PrintableString, self).__getstate__(),
@@ -4963,7 +4970,7 @@ class PrintableString(AllowableCharsMixin, CommonString):
 class TeletexString(CommonString):
     __slots__ = ()
     tag_default = tag_encode(20)
-    encoding = "ascii"
+    encoding = "iso-8859-1"
     asn1_type_name = "TeletexString"
 
 
@@ -4979,11 +4986,27 @@ class VideotexString(CommonString):
     asn1_type_name = "VideotexString"
 
 
-class IA5String(CommonString):
+class IA5String(AllowableCharsMixin, CommonString):
+    """IA5 string
+
+    Its value is properly sanitized: it is a mix of
+
+    * http://www.itscj.ipsj.or.jp/iso-ir/006.pdf (G)
+    * http://www.itscj.ipsj.or.jp/iso-ir/001.pdf (C0)
+    * DEL character (0x7F)
+
+    It is just 7-bit ASCII.
+
+    >>> IA5String().allowable_chars
+    frozenset(["NUL", ... "DEL"])
+    """
     __slots__ = ()
     tag_default = tag_encode(22)
     encoding = "ascii"
     asn1_type_name = "IA5"
+    _allowable_chars = frozenset(b"".join(
+        six_unichr(c).encode("ascii") for c in six_xrange(128)
+    ))
 
 
 LEN_YYMMDDHHMMSSZ = len("YYMMDDHHMMSSZ")
@@ -4994,11 +5017,27 @@ LEN_YYYYMMDDHHMMSSZ = len("YYYYMMDDHHMMSSZ")
 LEN_LEN_YYYYMMDDHHMMSSZ = len_encode(LEN_YYYYMMDDHHMMSSZ)
 
 
-class VisibleString(CommonString):
+class VisibleString(AllowableCharsMixin, CommonString):
+    """Visible string
+
+    Its value is properly sanitized. ASCII subset from space to tilde is
+    allowed: http://www.itscj.ipsj.or.jp/iso-ir/006.pdf
+
+    >>> VisibleString().allowable_chars
+    frozenset([" ", ... "~"])
+    """
     __slots__ = ()
     tag_default = tag_encode(26)
     encoding = "ascii"
     asn1_type_name = "VisibleString"
+    _allowable_chars = frozenset(b"".join(
+        six_unichr(c).encode("ascii") for c in six_xrange(ord(" "), ord("~") + 1)
+    ))
+
+
+class ISO646String(VisibleString):
+    __slots__ = ()
+    asn1_type_name = "ISO646String"
 
 
 UTCTimeState = namedtuple(
@@ -5418,11 +5457,6 @@ class GraphicString(CommonString):
     asn1_type_name = "GraphicString"
 
 
-class ISO646String(VisibleString):
-    __slots__ = ()
-    asn1_type_name = "ISO646String"
-
-
 class GeneralString(CommonString):
     __slots__ = ()
     tag_default = tag_encode(27)
@@ -5840,7 +5874,7 @@ class Any(Obj):
     def _value_sanitize(self, value):
         if value.__class__ == binary_type:
             if len(value) == 0:
-                raise ValueError("Any value can not be empty")
+                raise ValueError("%s value can not be empty" % self.__class__.__name__)
             return value
         if isinstance(value, self.__class__):
             return value._value
@@ -7400,6 +7434,400 @@ def generic_decoder():  # pragma: no cover
     return SEQUENCEOF(), pprint_any
 
 
+def ascii_visualize(ba):
+    """Output only ASCII printable characters, like in hexdump -C
+
+    Example output for given binary string (right part)::
+
+        92 2b 39 20 65 91 e6 8e  95 93 1a 58 df 02 78 ea  |.+9 e......X..x.|
+                                                           ^^^^^^^^^^^^^^^^
+    """
+    return "".join((six_unichr(b) if 0x20 <= b <= 0x7E else ".") for b in ba)
+
+
+def hexdump(raw):
+    """Generate ``hexdump -C`` like output
+
+    Rendered example::
+
+        00000000  30 80 30 80 a0 80 02 01  02 00 00 02 14 54 a5 18  |0.0..........T..|
+        00000010  69 ef 8b 3f 15 fd ea ad  bd 47 e0 94 81 6b 06 6a  |i..?.....G...k.j|
+
+    Result of that function is a generator of lines, where each line is
+    a list of columns::
+
+        [
+            [...],
+            ["00000010 ", " 69", " ef", " 8b", " 3f", " 15", " fd", " ea", " ad ",
+                          " bd", " 47", " e0", " 94", " 81", " 6b", " 06", " 6a ",
+                          " |i..?.....G...k.j|"]
+            [...],
+        ]
+    """
+    hexed = hexenc(raw).upper()
+    addr, cols = 0, ["%08x " % 0]
+    for i in six_xrange(0, len(hexed), 2):
+        if i != 0 and i // 2 % 8 == 0:
+            cols[-1] += " "
+        if i != 0 and i // 2 % 16 == 0:
+            cols.append(" |%s|" % ascii_visualize(bytearray(raw[addr:addr + 16])))
+            yield cols
+            addr += 16
+            cols = ["%08x " % addr]
+        cols.append(" " + hexed[i:i + 2])
+    if len(cols) > 0:
+        cols.append(" |%s|" % ascii_visualize(bytearray(raw[addr:])))
+        yield cols
+
+
+def browse(raw, obj, oid_maps=()):
+    """Interactive browser
+
+    :param bytes raw: binary data you decoded
+    :param obj: decoded :py:class:`pyderasn.Obj`
+    :param oid_maps: list of ``str(OID) <-> human readable string`` dictionaries.
+                     Its human readable form is printed when OID is met
+
+    .. note:: `urwid <http://urwid.org/>`__ dependency required
+
+    This browser is an interactive terminal application for browsing
+    structures of your decoded ASN.1 objects. You can quit it with **q**
+    key. It consists of three windows:
+
+    :tree:
+     View of ASN.1 elements hierarchy. You can navigate it using **Up**,
+     **Down**, **PageUp**, **PageDown**, **Home**, **End** keys.
+     **Left** key goes to constructed element above. **Plus**/**Minus**
+     keys collapse/uncollapse constructed elements. **Space** toggles it
+    :info:
+     window with various information about element. You can scroll it
+     with **h**/**l** (down, up) (**H**/**L** for triple speed) keys
+    :hexdump:
+     window with raw data hexdump and highlighted current element's
+     contents. It automatically focuses on element's data. You can
+     scroll it with **j**/**k** (down, up) (**J**/**K** for triple
+     speed) keys. If element has explicit tag, then it also will be
+     highlighted with different colour
+
+    Window's header contains current decode path and progress bars with
+    position in *info* and *hexdump* windows.
+
+    If you press **d**, then current element will be saved in the
+    current directory under its decode path name (adding ".0", ".1", etc
+    suffix if such file already exists). **D** will save it with explicit tag.
+
+    You can also invoke it with ``--browse`` command line argument.
+    """
+    from copy import deepcopy
+    from os.path import exists as path_exists
+    import urwid
+
+    class TW(urwid.TreeWidget):
+        def __init__(self, state, *args, **kwargs):
+            self.state = state
+            self.scrolled = {"info": False, "hexdump": False}
+            super(TW, self).__init__(*args, **kwargs)
+
+        def _get_pp(self):
+            pp = self.get_node().get_value()
+            constructed = len(pp) > 1
+            return (pp if hasattr(pp, "_fields") else pp[0]), constructed
+
+        def _state_update(self):
+            pp, _ = self._get_pp()
+            self.state["decode_path"].set_text(
+                ":".join(str(p) for p in pp.decode_path)
+            )
+            lines = deepcopy(self.state["hexed"])
+
+            def attr_set(i, attr):
+                line = lines[i // 16]
+                idx = 1 + (i - 16 * (i // 16))
+                line[idx] = (attr, line[idx])
+
+            if pp.expl_offset is not None:
+                for i in six_xrange(
+                        pp.expl_offset,
+                        pp.expl_offset + pp.expl_tlen + pp.expl_llen,
+                ):
+                    attr_set(i, "select-expl")
+            for i in six_xrange(pp.offset, pp.offset + pp.tlen + pp.llen + pp.vlen):
+                attr_set(i, "select-value")
+            self.state["hexdump"]._set_body([urwid.Text(line) for line in lines])
+            self.state["hexdump"].set_focus(pp.offset // 16)
+            self.state["hexdump"].set_focus_valign("middle")
+            self.state["hexdump_bar"].set_completion(
+                (100 * pp.offset // 16) //
+                len(self.state["hexdump"]._body.positions())
+            )
+
+            lines = [
+                [("header", "Name: "), pp.obj_name],
+                [("header", "Type: "), pp.asn1_type_name],
+                [("header", "Offset: "), "%d (0x%x)" % (pp.offset, pp.offset)],
+                [("header", "[TLV]len: "), "%d/%d/%d" % (
+                    pp.tlen, pp.llen, pp.vlen,
+                )],
+                [("header", "TLVlen: "), "%d" % sum((
+                    pp.tlen, pp.llen, pp.vlen,
+                ))],
+                [("header", "Slice: "), "[%d:%d]" % (
+                    pp.offset, pp.offset + pp.tlen + pp.llen + pp.vlen,
+                )],
+            ]
+            if pp.lenindef:
+                lines.append([("warning", "LENINDEF")])
+            if pp.ber_encoded:
+                lines.append([("warning", "BER encoded")])
+            if pp.bered:
+                lines.append([("warning", "BERed")])
+            if pp.expl is not None:
+                lines.append([("header", "EXPLICIT")])
+                klass, _, num = pp.expl
+                lines.append(["  Tag: %s%d" % (TagClassReprs[klass], num)])
+                if pp.expl_offset is not None:
+                    lines.append(["  Offset: %d" % pp.expl_offset])
+                    lines.append(["  [TLV]len: %d/%d/%d" % (
+                        pp.expl_tlen, pp.expl_llen, pp.expl_vlen,
+                    )])
+                    lines.append(["  TLVlen: %d" % sum((
+                        pp.expl_tlen, pp.expl_llen, pp.expl_vlen,
+                    ))])
+                    lines.append(["  Slice: [%d:%d]" % (
+                        pp.expl_offset,
+                        pp.expl_offset + pp.expl_tlen + pp.expl_llen + pp.expl_vlen,
+                    )])
+            if pp.impl is not None:
+                klass, _, num = pp.impl
+                lines.append([
+                    ("header", "IMPLICIT: "), "%s%d" % (TagClassReprs[klass], num),
+                ])
+            if pp.optional:
+                lines.append(["OPTIONAL"])
+            if pp.default:
+                lines.append(["DEFAULT"])
+            if len(pp.decode_path) > 0:
+                ent = pp.decode_path[-1]
+                if isinstance(ent, DecodePathDefBy):
+                    lines.append([""])
+                    value = str(ent.defined_by)
+                    oid_name = find_oid_name(
+                        ent.defined_by.asn1_type_name, oid_maps, value,
+                    )
+                    lines.append([("header", "DEFINED BY: "), "%s" % (
+                        value if oid_name is None
+                        else "%s (%s)" % (oid_name, value)
+                    )])
+            lines.append([""])
+            if pp.value is not None:
+                lines.append([("header", "Value: "), pp.value])
+                if (
+                        len(oid_maps) > 0 and
+                        pp.asn1_type_name == ObjectIdentifier.asn1_type_name
+                ):
+                    for oid_map in oid_maps:
+                        oid_name = oid_map.get(pp.value)
+                        if oid_name is not None:
+                            lines.append([("header", "Human: "), oid_name])
+                            break
+                if pp.asn1_type_name == Integer.asn1_type_name:
+                    lines.append([
+                        ("header", "Decimal: "), "%d" % int(pp.obj),
+                    ])
+                    lines.append([
+                        ("header", "Hexadecimal: "), colonize_hex(pp.obj.tohex()),
+                    ])
+            if pp.blob.__class__ == binary_type:
+                blob = hexenc(pp.blob).upper()
+                for i in six_xrange(0, len(blob), 32):
+                    lines.append([colonize_hex(blob[i:i + 32])])
+            elif pp.blob.__class__ == tuple:
+                lines.append([", ".join(pp.blob)])
+            self.state["info"]._set_body([urwid.Text(line) for line in lines])
+            self.state["info_bar"].set_completion(0)
+
+        def selectable(self):
+            if self.state["widget_current"] != self:
+                self.state["widget_current"] = self
+                self.scrolled["info"] = False
+                self.scrolled["hexdump"] = False
+                self._state_update()
+            return super(TW, self).selectable()
+
+        def get_display_text(self):
+            pp, constructed = self._get_pp()
+            style = "constructed" if constructed else ""
+            if len(pp.decode_path) == 0:
+                return (style, pp.obj_name)
+            if pp.asn1_type_name == "EOC":
+                return ("eoc", "EOC")
+            ent = pp.decode_path[-1]
+            if isinstance(ent, DecodePathDefBy):
+                value = str(ent.defined_by)
+                oid_name = find_oid_name(
+                    ent.defined_by.asn1_type_name, oid_maps, value,
+                )
+                return ("defby", "DEFBY:" + (
+                    value if oid_name is None else oid_name
+                ))
+            return (style, ent)
+
+        def _scroll(self, what, step):
+            self.state[what]._invalidate()
+            pos = self.state[what].focus_position
+            if not self.scrolled[what]:
+                self.scrolled[what] = True
+                pos -= 2
+            pos = max(0, pos + step)
+            pos = min(pos, len(self.state[what]._body.positions()) - 1)
+            self.state[what].set_focus(pos)
+            self.state[what].set_focus_valign("top")
+            self.state[what + "_bar"].set_completion(
+                (100 * pos) // len(self.state[what]._body.positions())
+            )
+
+        def keypress(self, size, key):
+            if key == "q":
+                raise urwid.ExitMainLoop()
+
+            if key == " ":
+                self.expanded = not self.expanded
+                self.update_expanded_icon()
+                return None
+
+            hexdump_steps = {"j": 1, "k": -1, "J": 5, "K": -5}
+            if key in hexdump_steps:
+                self._scroll("hexdump", hexdump_steps[key])
+                return None
+
+            info_steps = {"h": 1, "l": -1, "H": 5, "L": -5}
+            if key in info_steps:
+                self._scroll("info", info_steps[key])
+                return None
+
+            if key in ("d", "D"):
+                pp, _ = self._get_pp()
+                dp = ":".join(str(p) for p in pp.decode_path)
+                dp = dp.replace(" ", "_")
+                if dp == "":
+                    dp = "root"
+                if key == "d" or pp.expl_offset is None:
+                    data = self.state["raw"][pp.offset:(
+                        pp.offset + pp.tlen + pp.llen + pp.vlen
+                    )]
+                else:
+                    data = self.state["raw"][pp.expl_offset:(
+                        pp.expl_offset + pp.expl_tlen + pp.expl_llen + pp.expl_vlen
+                    )]
+                ctr = 0
+
+                def duplicate_path(dp, ctr):
+                    if ctr == 0:
+                        return dp
+                    return "%s.%d" % (dp, ctr)
+
+                while True:
+                    if not path_exists(duplicate_path(dp, ctr)):
+                        break
+                    ctr += 1
+                dp = duplicate_path(dp, ctr)
+                with open(dp, "wb") as fd:
+                    fd.write(data)
+                self.state["decode_path"].set_text(
+                    ("warning", "Saved to: " + dp)
+                )
+                return None
+            return super(TW, self).keypress(size, key)
+
+    class PN(urwid.ParentNode):
+        def __init__(self, state, value, *args, **kwargs):
+            self.state = state
+            if not hasattr(value, "_fields"):
+                value = list(value)
+            super(PN, self).__init__(value, *args, **kwargs)
+
+        def load_widget(self):
+            return TW(self.state, self)
+
+        def load_child_keys(self):
+            value = self.get_value()
+            if hasattr(value, "_fields"):
+                return []
+            return range(len(value[1:]))
+
+        def load_child_node(self, key):
+            return PN(
+                self.state,
+                self.get_value()[key + 1],
+                parent=self,
+                key=key,
+                depth=self.get_depth() + 1,
+            )
+
+    class LabeledPG(urwid.ProgressBar):
+        def __init__(self, label, *args, **kwargs):
+            self.label = label
+            super(LabeledPG, self).__init__(*args, **kwargs)
+
+        def get_text(self):
+            return "%s: %s" % (self.label, super(LabeledPG, self).get_text())
+
+    WinHexdump = urwid.ListBox([urwid.Text("")])
+    WinInfo = urwid.ListBox([urwid.Text("")])
+    WinDecodePath = urwid.Text("", "center")
+    WinInfoBar = LabeledPG("info", "pg-normal", "pg-complete")
+    WinHexdumpBar = LabeledPG("hexdump", "pg-normal", "pg-complete")
+    WinTree = urwid.TreeListBox(urwid.TreeWalker(PN(
+        {
+            "raw": raw,
+            "hexed": list(hexdump(raw)),
+            "widget_current": None,
+            "info": WinInfo,
+            "info_bar": WinInfoBar,
+            "hexdump": WinHexdump,
+            "hexdump_bar": WinHexdumpBar,
+            "decode_path": WinDecodePath,
+        },
+        list(obj.pps()),
+    )))
+    help_text = " ".join((
+        "q:quit",
+        "space:(un)collapse",
+        "(pg)up/down/home/end:nav",
+        "jkJK:hexdump hlHL:info",
+        "dD:dump",
+    ))
+    urwid.MainLoop(
+        urwid.Frame(
+            urwid.Columns([
+                ("weight", 1, WinTree),
+                ("weight", 2, urwid.Pile([
+                    urwid.LineBox(WinInfo),
+                    urwid.LineBox(WinHexdump),
+                ])),
+            ]),
+            header=urwid.Columns([
+                ("weight", 2, urwid.AttrWrap(WinDecodePath, "header")),
+                ("weight", 1, WinInfoBar),
+                ("weight", 1, WinHexdumpBar),
+            ]),
+            footer=urwid.AttrWrap(urwid.Text(help_text), "help")
+        ),
+        [
+            ("header", "bold", ""),
+            ("constructed", "bold", ""),
+            ("help", "light magenta", ""),
+            ("warning", "light red", ""),
+            ("defby", "light red", ""),
+            ("eoc", "dark red", ""),
+            ("select-value", "light green", ""),
+            ("select-expl", "light red", ""),
+            ("pg-normal", "", "light blue"),
+            ("pg-complete", "black", "yellow"),
+        ],
+    ).run()
+
+
 def main():  # pragma: no cover
     import argparse
     parser = argparse.ArgumentParser(description="PyDERASN ASN.1 BER/CER/DER decoder")
@@ -7445,6 +7873,11 @@ def main():  # pragma: no cover
         action="store_true",
         help="Turn on event generation mode",
     )
+    parser.add_argument(
+        "--browse",
+        action="store_true",
+        help="Start ASN.1 browser",
+    )
     parser.add_argument(
         "RAWFile",
         type=argparse.FileType("rb"),
@@ -7473,6 +7906,11 @@ def main():  # pragma: no cover
     }
     if args.defines_by_path is not None:
         ctx["defines_by_path"] = obj_by_path(args.defines_by_path)
+    if args.browse:
+        obj, _ = schema().decode(raw, ctx=ctx)
+        browse(raw, obj, oid_maps)
+        from sys import exit as sys_exit
+        sys_exit(0)
     from os import environ
     pprinter = partial(
         pprinter,
@@ -7495,4 +7933,5 @@ def main():  # pragma: no cover
 
 
 if __name__ == "__main__":
+    from pyderasn import *
     main()