Initial Contribution
diff --git a/froofle/protobuf/internal/encoder.py b/froofle/protobuf/internal/encoder.py
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+# Protocol Buffers - Google's data interchange format
+# Copyright 2008 Google Inc. All rights reserved.
+# http://code.google.com/p/protobuf/
+#
+# Redistribution and use in source and binary forms, with or without
+# modification, are permitted provided that the following conditions are
+# met:
+#
+# * Redistributions of source code must retain the above copyright
+# notice, this list of conditions and the following disclaimer.
+# * Redistributions in binary form must reproduce the above
+# copyright notice, this list of conditions and the following disclaimer
+# in the documentation and/or other materials provided with the
+# distribution.
+# * Neither the name of Google Inc. nor the names of its
+# contributors may be used to endorse or promote products derived from
+# this software without specific prior written permission.
+#
+# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+# "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+# LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+# A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+# OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+# SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+# LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+# DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+# THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+# (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+# OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+"""Class for encoding protocol message primitives.
+
+Contains the logic for encoding every logical protocol field type
+into one of the 5 physical wire types.
+"""
+
+__author__ = 'robinson@google.com (Will Robinson)'
+
+import struct
+from froofle.protobuf import message
+from froofle.protobuf.internal import wire_format
+from froofle.protobuf.internal import output_stream
+
+
+# Note that much of this code is ported from //net/proto/ProtocolBuffer, and
+# that the interface is strongly inspired by WireFormat from the C++ proto2
+# implementation.
+
+
+class Encoder(object):
+
+ """Encodes logical protocol buffer fields to the wire format."""
+
+ def __init__(self):
+ self._stream = output_stream.OutputStream()
+
+ def ToString(self):
+ """Returns all values encoded in this object as a string."""
+ return self._stream.ToString()
+
+ # All the Append*() methods below first append a tag+type pair to the buffer
+ # before appending the specified value.
+
+ def AppendInt32(self, field_number, value):
+ """Appends a 32-bit integer to our buffer, varint-encoded."""
+ self._AppendTag(field_number, wire_format.WIRETYPE_VARINT)
+ self._stream.AppendVarint32(value)
+
+ def AppendInt64(self, field_number, value):
+ """Appends a 64-bit integer to our buffer, varint-encoded."""
+ self._AppendTag(field_number, wire_format.WIRETYPE_VARINT)
+ self._stream.AppendVarint64(value)
+
+ def AppendUInt32(self, field_number, unsigned_value):
+ """Appends an unsigned 32-bit integer to our buffer, varint-encoded."""
+ self._AppendTag(field_number, wire_format.WIRETYPE_VARINT)
+ self._stream.AppendVarUInt32(unsigned_value)
+
+ def AppendUInt64(self, field_number, unsigned_value):
+ """Appends an unsigned 64-bit integer to our buffer, varint-encoded."""
+ self._AppendTag(field_number, wire_format.WIRETYPE_VARINT)
+ self._stream.AppendVarUInt64(unsigned_value)
+
+ def AppendSInt32(self, field_number, value):
+ """Appends a 32-bit integer to our buffer, zigzag-encoded and then
+ varint-encoded.
+ """
+ self._AppendTag(field_number, wire_format.WIRETYPE_VARINT)
+ zigzag_value = wire_format.ZigZagEncode(value)
+ self._stream.AppendVarUInt32(zigzag_value)
+
+ def AppendSInt64(self, field_number, value):
+ """Appends a 64-bit integer to our buffer, zigzag-encoded and then
+ varint-encoded.
+ """
+ self._AppendTag(field_number, wire_format.WIRETYPE_VARINT)
+ zigzag_value = wire_format.ZigZagEncode(value)
+ self._stream.AppendVarUInt64(zigzag_value)
+
+ def AppendFixed32(self, field_number, unsigned_value):
+ """Appends an unsigned 32-bit integer to our buffer, in little-endian
+ byte-order.
+ """
+ self._AppendTag(field_number, wire_format.WIRETYPE_FIXED32)
+ self._stream.AppendLittleEndian32(unsigned_value)
+
+ def AppendFixed64(self, field_number, unsigned_value):
+ """Appends an unsigned 64-bit integer to our buffer, in little-endian
+ byte-order.
+ """
+ self._AppendTag(field_number, wire_format.WIRETYPE_FIXED64)
+ self._stream.AppendLittleEndian64(unsigned_value)
+
+ def AppendSFixed32(self, field_number, value):
+ """Appends a signed 32-bit integer to our buffer, in little-endian
+ byte-order.
+ """
+ sign = (value & 0x80000000) and -1 or 0
+ if value >> 32 != sign:
+ raise message.EncodeError('SFixed32 out of range: %d' % value)
+ self._AppendTag(field_number, wire_format.WIRETYPE_FIXED32)
+ self._stream.AppendLittleEndian32(value & 0xffffffff)
+
+ def AppendSFixed64(self, field_number, value):
+ """Appends a signed 64-bit integer to our buffer, in little-endian
+ byte-order.
+ """
+ sign = (value & 0x8000000000000000) and -1 or 0
+ if value >> 64 != sign:
+ raise message.EncodeError('SFixed64 out of range: %d' % value)
+ self._AppendTag(field_number, wire_format.WIRETYPE_FIXED64)
+ self._stream.AppendLittleEndian64(value & 0xffffffffffffffff)
+
+ def AppendFloat(self, field_number, value):
+ """Appends a floating-point number to our buffer."""
+ self._AppendTag(field_number, wire_format.WIRETYPE_FIXED32)
+ self._stream.AppendRawBytes(struct.pack('f', value))
+
+ def AppendDouble(self, field_number, value):
+ """Appends a double-precision floating-point number to our buffer."""
+ self._AppendTag(field_number, wire_format.WIRETYPE_FIXED64)
+ self._stream.AppendRawBytes(struct.pack('d', value))
+
+ def AppendBool(self, field_number, value):
+ """Appends a boolean to our buffer."""
+ self.AppendInt32(field_number, value)
+
+ def AppendEnum(self, field_number, value):
+ """Appends an enum value to our buffer."""
+ self.AppendInt32(field_number, value)
+
+ def AppendString(self, field_number, value):
+ """Appends a length-prefixed unicode string, encoded as UTF-8 to our buffer,
+ with the length varint-encoded.
+ """
+ self.AppendBytes(field_number, value.encode('utf-8'))
+
+ def AppendBytes(self, field_number, value):
+ """Appends a length-prefixed sequence of bytes to our buffer, with the
+ length varint-encoded.
+ """
+ self._AppendTag(field_number, wire_format.WIRETYPE_LENGTH_DELIMITED)
+ self._stream.AppendVarUInt32(len(value))
+ self._stream.AppendRawBytes(value)
+
+ # TODO(robinson): For AppendGroup() and AppendMessage(), we'd really like to
+ # avoid the extra string copy here. We can do so if we widen the Message
+ # interface to be able to serialize to a stream in addition to a string. The
+ # challenge when thinking ahead to the Python/C API implementation of Message
+ # is finding a stream-like Python thing to which we can write raw bytes
+ # from C. I'm not sure such a thing exists(?). (array.array is pretty much
+ # what we want, but it's not directly exposed in the Python/C API).
+
+ def AppendGroup(self, field_number, group):
+ """Appends a group to our buffer.
+ """
+ self._AppendTag(field_number, wire_format.WIRETYPE_START_GROUP)
+ self._stream.AppendRawBytes(group.SerializeToString())
+ self._AppendTag(field_number, wire_format.WIRETYPE_END_GROUP)
+
+ def AppendMessage(self, field_number, msg):
+ """Appends a nested message to our buffer.
+ """
+ self._AppendTag(field_number, wire_format.WIRETYPE_LENGTH_DELIMITED)
+ self._stream.AppendVarUInt32(msg.ByteSize())
+ self._stream.AppendRawBytes(msg.SerializeToString())
+
+ def AppendMessageSetItem(self, field_number, msg):
+ """Appends an item using the message set wire format.
+
+ The message set message looks like this:
+ message MessageSet {
+ repeated group Item = 1 {
+ required int32 type_id = 2;
+ required string message = 3;
+ }
+ }
+ """
+ self._AppendTag(1, wire_format.WIRETYPE_START_GROUP)
+ self.AppendInt32(2, field_number)
+ self.AppendMessage(3, msg)
+ self._AppendTag(1, wire_format.WIRETYPE_END_GROUP)
+
+ def _AppendTag(self, field_number, wire_type):
+ """Appends a tag containing field number and wire type information."""
+ self._stream.AppendVarUInt32(wire_format.PackTag(field_number, wire_type))