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Diffstat (limited to 'python/google/protobuf/internal/encoder.py')
| -rwxr-xr-x | python/google/protobuf/internal/encoder.py | 280 |
1 files changed, 280 insertions, 0 deletions
diff --git a/python/google/protobuf/internal/encoder.py b/python/google/protobuf/internal/encoder.py new file mode 100755 index 0000000..3ec3b2b --- /dev/null +++ b/python/google/protobuf/internal/encoder.py @@ -0,0 +1,280 @@ +# 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 google.protobuf import message +from google.protobuf.internal import wire_format +from google.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() + + # Append*NoTag methods. These are necessary for serializing packed + # repeated fields. The Append*() methods call these methods to do + # the actual serialization. + def AppendInt32NoTag(self, value): + """Appends a 32-bit integer to our buffer, varint-encoded.""" + self._stream.AppendVarint32(value) + + def AppendInt64NoTag(self, value): + """Appends a 64-bit integer to our buffer, varint-encoded.""" + self._stream.AppendVarint64(value) + + def AppendUInt32NoTag(self, unsigned_value): + """Appends an unsigned 32-bit integer to our buffer, varint-encoded.""" + self._stream.AppendVarUInt32(unsigned_value) + + def AppendUInt64NoTag(self, unsigned_value): + """Appends an unsigned 64-bit integer to our buffer, varint-encoded.""" + self._stream.AppendVarUInt64(unsigned_value) + + def AppendSInt32NoTag(self, value): + """Appends a 32-bit integer to our buffer, zigzag-encoded and then + varint-encoded. + """ + zigzag_value = wire_format.ZigZagEncode(value) + self._stream.AppendVarUInt32(zigzag_value) + + def AppendSInt64NoTag(self, value): + """Appends a 64-bit integer to our buffer, zigzag-encoded and then + varint-encoded. + """ + zigzag_value = wire_format.ZigZagEncode(value) + self._stream.AppendVarUInt64(zigzag_value) + + def AppendFixed32NoTag(self, unsigned_value): + """Appends an unsigned 32-bit integer to our buffer, in little-endian + byte-order. + """ + self._stream.AppendLittleEndian32(unsigned_value) + + def AppendFixed64NoTag(self, unsigned_value): + """Appends an unsigned 64-bit integer to our buffer, in little-endian + byte-order. + """ + self._stream.AppendLittleEndian64(unsigned_value) + + def AppendSFixed32NoTag(self, 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._stream.AppendLittleEndian32(value & 0xffffffff) + + def AppendSFixed64NoTag(self, 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._stream.AppendLittleEndian64(value & 0xffffffffffffffff) + + def AppendFloatNoTag(self, value): + """Appends a floating-point number to our buffer.""" + self._stream.AppendRawBytes( + struct.pack(wire_format.FORMAT_FLOAT_LITTLE_ENDIAN, value)) + + def AppendDoubleNoTag(self, value): + """Appends a double-precision floating-point number to our buffer.""" + self._stream.AppendRawBytes( + struct.pack(wire_format.FORMAT_DOUBLE_LITTLE_ENDIAN, value)) + + def AppendBoolNoTag(self, value): + """Appends a boolean to our buffer.""" + self.AppendInt32NoTag(value) + + def AppendEnumNoTag(self, value): + """Appends an enum value to our buffer.""" + self.AppendInt32NoTag(value) + + + # 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.AppendInt32NoTag(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.AppendInt64NoTag(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.AppendUInt32NoTag(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.AppendUInt64NoTag(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) + self.AppendSInt32NoTag(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) + self.AppendSInt64NoTag(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.AppendFixed32NoTag(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.AppendFixed64NoTag(unsigned_value) + + def AppendSFixed32(self, field_number, value): + """Appends a signed 32-bit integer to our buffer, in little-endian + byte-order. + """ + self.AppendTag(field_number, wire_format.WIRETYPE_FIXED32) + self.AppendSFixed32NoTag(value) + + def AppendSFixed64(self, field_number, value): + """Appends a signed 64-bit integer to our buffer, in little-endian + byte-order. + """ + self.AppendTag(field_number, wire_format.WIRETYPE_FIXED64) + self.AppendSFixed64NoTag(value) + + def AppendFloat(self, field_number, value): + """Appends a floating-point number to our buffer.""" + self.AppendTag(field_number, wire_format.WIRETYPE_FIXED32) + self.AppendFloatNoTag(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.AppendDoubleNoTag(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)) |