kaitai: adjustments and rearrangements for python2/3 compat

1 files changed, 150 insertions, 0 deletions

diff --git a/python/examples/kaitai/google_protobuf.py b/python/examples/kaitai/google_protobuf.py
new file mode 100644
index 00000000..27b4b2ef
--- /dev/null
+++ b/python/examples/kaitai/google_protobuf.py
@@ -0,0 +1,150 @@
+# This is a generated file! Please edit source .ksy file and use kaitai-struct-compiler to rebuild
+
+from pkg_resources import parse_version
+from .kaitaistruct import __version__ as ks_version, KaitaiStruct, KaitaiStream, BytesIO
+import collections
+from enum import Enum
+
+
+if parse_version(ks_version) < parse_version('0.7'):
+    raise Exception("Incompatible Kaitai Struct Python API: 0.7 or later is required, but you have %s" % (ks_version))
+
+from vlq_base128_le import VlqBase128Le
+class GoogleProtobuf(KaitaiStruct):
+    """Google Protocol Buffers (AKA protobuf) is a popular data
+    serialization scheme used for communication protocols, data storage,
+    etc. There are implementations are available for almost every
+    popular language. The focus points of this scheme are brevity (data
+    is encoded in a very size-efficient manner) and extensibility (one
+    can add keys to the structure, while keeping it readable in previous
+    version of software).
+    
+    Protobuf uses semi-self-describing encoding scheme for its
+    messages. It means that it is possible to parse overall structure of
+    the message (skipping over fields one can't understand), but to
+    fully understand the message, one needs a protocol definition file
+    (`.proto`). To be specific:
+    
+    * "Keys" in key-value pairs provided in the message are identified
+      only with an integer "field tag". `.proto` file provides info on
+      which symbolic field names these field tags map to.
+    * "Keys" also provide something called "wire type". It's not a data
+      type in its common sense (i.e. you can't, for example, distinguish
+      `sint32` vs `uint32` vs some enum, or `string` from `bytes`), but
+      it's enough information to determine how many bytes to
+      parse. Interpretation of the value should be done according to the
+      type specified in `.proto` file.
+    * There's no direct information on which fields are optional /
+      required, which fields may be repeated or constitute a map, what
+      restrictions are placed on fields usage in a single message, what
+      are the fields' default values, etc, etc.
+    
+    .. seealso::
+       Source - https://developers.google.com/protocol-buffers/docs/encoding
+    """
+    SEQ_FIELDS = ["pairs"]
+    def __init__(self, _io, _parent=None, _root=None):
+        self._io = _io
+        self._parent = _parent
+        self._root = _root if _root else self
+        self._debug = collections.defaultdict(dict)
+
+    def _read(self):
+        self._debug['pairs']['start'] = self._io.pos()
+        self.pairs = []
+        i = 0
+        while not self._io.is_eof():
+            if not 'arr' in self._debug['pairs']:
+                self._debug['pairs']['arr'] = []
+            self._debug['pairs']['arr'].append({'start': self._io.pos()})
+            _t_pairs = self._root.Pair(self._io, self, self._root)
+            _t_pairs._read()
+            self.pairs.append(_t_pairs)
+            self._debug['pairs']['arr'][len(self.pairs) - 1]['end'] = self._io.pos()
+            i += 1
+
+        self._debug['pairs']['end'] = self._io.pos()
+
+    class Pair(KaitaiStruct):
+        """Key-value pair."""
+
+        class WireTypes(Enum):
+            varint = 0
+            bit_64 = 1
+            len_delimited = 2
+            group_start = 3
+            group_end = 4
+            bit_32 = 5
+        SEQ_FIELDS = ["key", "value"]
+        def __init__(self, _io, _parent=None, _root=None):
+            self._io = _io
+            self._parent = _parent
+            self._root = _root if _root else self
+            self._debug = collections.defaultdict(dict)
+
+        def _read(self):
+            self._debug['key']['start'] = self._io.pos()
+            self.key = VlqBase128Le(self._io)
+            self.key._read()
+            self._debug['key']['end'] = self._io.pos()
+            self._debug['value']['start'] = self._io.pos()
+            _on = self.wire_type
+            if _on == self._root.Pair.WireTypes.varint:
+                self.value = VlqBase128Le(self._io)
+                self.value._read()
+            elif _on == self._root.Pair.WireTypes.len_delimited:
+                self.value = self._root.DelimitedBytes(self._io, self, self._root)
+                self.value._read()
+            elif _on == self._root.Pair.WireTypes.bit_64:
+                self.value = self._io.read_u8le()
+            elif _on == self._root.Pair.WireTypes.bit_32:
+                self.value = self._io.read_u4le()
+            self._debug['value']['end'] = self._io.pos()
+
+        @property
+        def wire_type(self):
+            """"Wire type" is a part of the "key" that carries enough
+            information to parse value from the wire, i.e. read correct
+            amount of bytes, but there's not enough informaton to
+            interprete in unambiguously. For example, one can't clearly
+            distinguish 64-bit fixed-sized integers from 64-bit floats,
+            signed zigzag-encoded varints from regular unsigned varints,
+            arbitrary bytes from UTF-8 encoded strings, etc.
+            """
+            if hasattr(self, '_m_wire_type'):
+                return self._m_wire_type if hasattr(self, '_m_wire_type') else None
+
+            self._m_wire_type = KaitaiStream.resolve_enum(self._root.Pair.WireTypes, (self.key.value & 7))
+            return self._m_wire_type if hasattr(self, '_m_wire_type') else None
+
+        @property
+        def field_tag(self):
+            """Identifies a field of protocol. One can look up symbolic
+            field name in a `.proto` file by this field tag.
+            """
+            if hasattr(self, '_m_field_tag'):
+                return self._m_field_tag if hasattr(self, '_m_field_tag') else None
+
+            self._m_field_tag = (self.key.value >> 3)
+            return self._m_field_tag if hasattr(self, '_m_field_tag') else None
+
+
+    class DelimitedBytes(KaitaiStruct):
+        SEQ_FIELDS = ["len", "body"]
+        def __init__(self, _io, _parent=None, _root=None):
+            self._io = _io
+            self._parent = _parent
+            self._root = _root if _root else self
+            self._debug = collections.defaultdict(dict)
+
+        def _read(self):
+            self._debug['len']['start'] = self._io.pos()
+            self.len = VlqBase128Le(self._io)
+            self.len._read()
+            self._debug['len']['end'] = self._io.pos()
+            self._debug['body']['start'] = self._io.pos()
+            self.body = self._io.read_bytes(self.len.value)
+            self._debug['body']['end'] = self._io.pos()
+
+
+