807 lines
27 KiB
Python
807 lines
27 KiB
Python
# Protocol Buffers - Google's data interchange format
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# Copyright 2008 Google Inc. All rights reserved.
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#
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# Use of this source code is governed by a BSD-style
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# license that can be found in the LICENSE file or at
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# https://developers.google.com/open-source/licenses/bsd
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"""Code for encoding protocol message primitives.
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Contains the logic for encoding every logical protocol field type
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into one of the 5 physical wire types.
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This code is designed to push the Python interpreter's performance to the
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limits.
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The basic idea is that at startup time, for every field (i.e. every
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FieldDescriptor) we construct two functions: a "sizer" and an "encoder". The
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sizer takes a value of this field's type and computes its byte size. The
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encoder takes a writer function and a value. It encodes the value into byte
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strings and invokes the writer function to write those strings. Typically the
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writer function is the write() method of a BytesIO.
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We try to do as much work as possible when constructing the writer and the
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sizer rather than when calling them. In particular:
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* We copy any needed global functions to local variables, so that we do not need
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to do costly global table lookups at runtime.
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* Similarly, we try to do any attribute lookups at startup time if possible.
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* Every field's tag is encoded to bytes at startup, since it can't change at
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runtime.
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* Whatever component of the field size we can compute at startup, we do.
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* We *avoid* sharing code if doing so would make the code slower and not sharing
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does not burden us too much. For example, encoders for repeated fields do
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not just call the encoders for singular fields in a loop because this would
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add an extra function call overhead for every loop iteration; instead, we
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manually inline the single-value encoder into the loop.
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* If a Python function lacks a return statement, Python actually generates
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instructions to pop the result of the last statement off the stack, push
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None onto the stack, and then return that. If we really don't care what
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value is returned, then we can save two instructions by returning the
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result of the last statement. It looks funny but it helps.
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* We assume that type and bounds checking has happened at a higher level.
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"""
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__author__ = 'kenton@google.com (Kenton Varda)'
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import struct
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from google.protobuf.internal import wire_format
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# This will overflow and thus become IEEE-754 "infinity". We would use
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# "float('inf')" but it doesn't work on Windows pre-Python-2.6.
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_POS_INF = 1e10000
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_NEG_INF = -_POS_INF
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def _VarintSize(value):
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"""Compute the size of a varint value."""
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if value <= 0x7f: return 1
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if value <= 0x3fff: return 2
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if value <= 0x1fffff: return 3
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if value <= 0xfffffff: return 4
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if value <= 0x7ffffffff: return 5
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if value <= 0x3ffffffffff: return 6
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if value <= 0x1ffffffffffff: return 7
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if value <= 0xffffffffffffff: return 8
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if value <= 0x7fffffffffffffff: return 9
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return 10
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def _SignedVarintSize(value):
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"""Compute the size of a signed varint value."""
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if value < 0: return 10
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if value <= 0x7f: return 1
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if value <= 0x3fff: return 2
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if value <= 0x1fffff: return 3
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if value <= 0xfffffff: return 4
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if value <= 0x7ffffffff: return 5
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if value <= 0x3ffffffffff: return 6
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if value <= 0x1ffffffffffff: return 7
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if value <= 0xffffffffffffff: return 8
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if value <= 0x7fffffffffffffff: return 9
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return 10
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def _TagSize(field_number):
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"""Returns the number of bytes required to serialize a tag with this field
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number."""
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# Just pass in type 0, since the type won't affect the tag+type size.
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return _VarintSize(wire_format.PackTag(field_number, 0))
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# --------------------------------------------------------------------
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# In this section we define some generic sizers. Each of these functions
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# takes parameters specific to a particular field type, e.g. int32 or fixed64.
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# It returns another function which in turn takes parameters specific to a
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# particular field, e.g. the field number and whether it is repeated or packed.
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# Look at the next section to see how these are used.
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def _SimpleSizer(compute_value_size):
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"""A sizer which uses the function compute_value_size to compute the size of
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each value. Typically compute_value_size is _VarintSize."""
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def SpecificSizer(field_number, is_repeated, is_packed):
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tag_size = _TagSize(field_number)
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if is_packed:
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local_VarintSize = _VarintSize
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def PackedFieldSize(value):
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result = 0
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for element in value:
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result += compute_value_size(element)
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return result + local_VarintSize(result) + tag_size
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return PackedFieldSize
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elif is_repeated:
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def RepeatedFieldSize(value):
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result = tag_size * len(value)
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for element in value:
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result += compute_value_size(element)
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return result
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return RepeatedFieldSize
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else:
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def FieldSize(value):
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return tag_size + compute_value_size(value)
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return FieldSize
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return SpecificSizer
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def _ModifiedSizer(compute_value_size, modify_value):
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"""Like SimpleSizer, but modify_value is invoked on each value before it is
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passed to compute_value_size. modify_value is typically ZigZagEncode."""
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def SpecificSizer(field_number, is_repeated, is_packed):
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tag_size = _TagSize(field_number)
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if is_packed:
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local_VarintSize = _VarintSize
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def PackedFieldSize(value):
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result = 0
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for element in value:
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result += compute_value_size(modify_value(element))
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return result + local_VarintSize(result) + tag_size
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return PackedFieldSize
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elif is_repeated:
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def RepeatedFieldSize(value):
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result = tag_size * len(value)
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for element in value:
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result += compute_value_size(modify_value(element))
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return result
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return RepeatedFieldSize
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else:
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def FieldSize(value):
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return tag_size + compute_value_size(modify_value(value))
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return FieldSize
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return SpecificSizer
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def _FixedSizer(value_size):
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"""Like _SimpleSizer except for a fixed-size field. The input is the size
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of one value."""
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def SpecificSizer(field_number, is_repeated, is_packed):
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tag_size = _TagSize(field_number)
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if is_packed:
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local_VarintSize = _VarintSize
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def PackedFieldSize(value):
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result = len(value) * value_size
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return result + local_VarintSize(result) + tag_size
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return PackedFieldSize
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elif is_repeated:
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element_size = value_size + tag_size
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def RepeatedFieldSize(value):
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return len(value) * element_size
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return RepeatedFieldSize
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else:
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field_size = value_size + tag_size
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def FieldSize(value):
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return field_size
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return FieldSize
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return SpecificSizer
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# ====================================================================
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# Here we declare a sizer constructor for each field type. Each "sizer
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# constructor" is a function that takes (field_number, is_repeated, is_packed)
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# as parameters and returns a sizer, which in turn takes a field value as
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# a parameter and returns its encoded size.
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Int32Sizer = Int64Sizer = EnumSizer = _SimpleSizer(_SignedVarintSize)
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UInt32Sizer = UInt64Sizer = _SimpleSizer(_VarintSize)
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SInt32Sizer = SInt64Sizer = _ModifiedSizer(
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_SignedVarintSize, wire_format.ZigZagEncode)
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Fixed32Sizer = SFixed32Sizer = FloatSizer = _FixedSizer(4)
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Fixed64Sizer = SFixed64Sizer = DoubleSizer = _FixedSizer(8)
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BoolSizer = _FixedSizer(1)
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def StringSizer(field_number, is_repeated, is_packed):
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"""Returns a sizer for a string field."""
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tag_size = _TagSize(field_number)
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local_VarintSize = _VarintSize
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local_len = len
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assert not is_packed
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if is_repeated:
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def RepeatedFieldSize(value):
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result = tag_size * len(value)
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for element in value:
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l = local_len(element.encode('utf-8'))
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result += local_VarintSize(l) + l
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return result
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return RepeatedFieldSize
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else:
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def FieldSize(value):
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l = local_len(value.encode('utf-8'))
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return tag_size + local_VarintSize(l) + l
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return FieldSize
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def BytesSizer(field_number, is_repeated, is_packed):
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"""Returns a sizer for a bytes field."""
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tag_size = _TagSize(field_number)
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local_VarintSize = _VarintSize
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local_len = len
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assert not is_packed
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if is_repeated:
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def RepeatedFieldSize(value):
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result = tag_size * len(value)
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for element in value:
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l = local_len(element)
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result += local_VarintSize(l) + l
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return result
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return RepeatedFieldSize
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else:
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def FieldSize(value):
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l = local_len(value)
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return tag_size + local_VarintSize(l) + l
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return FieldSize
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def GroupSizer(field_number, is_repeated, is_packed):
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"""Returns a sizer for a group field."""
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tag_size = _TagSize(field_number) * 2
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assert not is_packed
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if is_repeated:
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def RepeatedFieldSize(value):
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result = tag_size * len(value)
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for element in value:
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result += element.ByteSize()
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return result
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return RepeatedFieldSize
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else:
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def FieldSize(value):
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return tag_size + value.ByteSize()
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return FieldSize
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def MessageSizer(field_number, is_repeated, is_packed):
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"""Returns a sizer for a message field."""
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tag_size = _TagSize(field_number)
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local_VarintSize = _VarintSize
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assert not is_packed
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if is_repeated:
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def RepeatedFieldSize(value):
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result = tag_size * len(value)
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for element in value:
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l = element.ByteSize()
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result += local_VarintSize(l) + l
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return result
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return RepeatedFieldSize
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else:
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def FieldSize(value):
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l = value.ByteSize()
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return tag_size + local_VarintSize(l) + l
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return FieldSize
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# --------------------------------------------------------------------
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# MessageSet is special: it needs custom logic to compute its size properly.
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def MessageSetItemSizer(field_number):
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"""Returns a sizer for extensions of MessageSet.
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The message set message looks like this:
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message MessageSet {
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repeated group Item = 1 {
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required int32 type_id = 2;
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required string message = 3;
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}
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}
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"""
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static_size = (_TagSize(1) * 2 + _TagSize(2) + _VarintSize(field_number) +
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_TagSize(3))
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local_VarintSize = _VarintSize
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def FieldSize(value):
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l = value.ByteSize()
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return static_size + local_VarintSize(l) + l
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return FieldSize
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# --------------------------------------------------------------------
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# Map is special: it needs custom logic to compute its size properly.
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def MapSizer(field_descriptor, is_message_map):
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"""Returns a sizer for a map field."""
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# Can't look at field_descriptor.message_type._concrete_class because it may
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# not have been initialized yet.
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message_type = field_descriptor.message_type
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message_sizer = MessageSizer(field_descriptor.number, False, False)
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def FieldSize(map_value):
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total = 0
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for key in map_value:
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value = map_value[key]
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# It's wasteful to create the messages and throw them away one second
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# later since we'll do the same for the actual encode. But there's not an
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# obvious way to avoid this within the current design without tons of code
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# duplication. For message map, value.ByteSize() should be called to
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# update the status.
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entry_msg = message_type._concrete_class(key=key, value=value)
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total += message_sizer(entry_msg)
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if is_message_map:
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value.ByteSize()
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return total
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return FieldSize
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# ====================================================================
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# Encoders!
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def _VarintEncoder():
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"""Return an encoder for a basic varint value (does not include tag)."""
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local_int2byte = struct.Struct('>B').pack
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def EncodeVarint(write, value, unused_deterministic=None):
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bits = value & 0x7f
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value >>= 7
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while value:
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write(local_int2byte(0x80|bits))
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bits = value & 0x7f
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value >>= 7
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return write(local_int2byte(bits))
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return EncodeVarint
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def _SignedVarintEncoder():
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"""Return an encoder for a basic signed varint value (does not include
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tag)."""
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local_int2byte = struct.Struct('>B').pack
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def EncodeSignedVarint(write, value, unused_deterministic=None):
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if value < 0:
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value += (1 << 64)
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bits = value & 0x7f
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value >>= 7
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while value:
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write(local_int2byte(0x80|bits))
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bits = value & 0x7f
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value >>= 7
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return write(local_int2byte(bits))
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return EncodeSignedVarint
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_EncodeVarint = _VarintEncoder()
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_EncodeSignedVarint = _SignedVarintEncoder()
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def _VarintBytes(value):
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"""Encode the given integer as a varint and return the bytes. This is only
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called at startup time so it doesn't need to be fast."""
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pieces = []
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_EncodeVarint(pieces.append, value, True)
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return b"".join(pieces)
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def TagBytes(field_number, wire_type):
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"""Encode the given tag and return the bytes. Only called at startup."""
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return bytes(_VarintBytes(wire_format.PackTag(field_number, wire_type)))
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# --------------------------------------------------------------------
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# As with sizers (see above), we have a number of common encoder
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# implementations.
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def _SimpleEncoder(wire_type, encode_value, compute_value_size):
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"""Return a constructor for an encoder for fields of a particular type.
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Args:
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wire_type: The field's wire type, for encoding tags.
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encode_value: A function which encodes an individual value, e.g.
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_EncodeVarint().
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compute_value_size: A function which computes the size of an individual
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value, e.g. _VarintSize().
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"""
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def SpecificEncoder(field_number, is_repeated, is_packed):
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if is_packed:
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tag_bytes = TagBytes(field_number, wire_format.WIRETYPE_LENGTH_DELIMITED)
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local_EncodeVarint = _EncodeVarint
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def EncodePackedField(write, value, deterministic):
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write(tag_bytes)
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size = 0
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for element in value:
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size += compute_value_size(element)
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local_EncodeVarint(write, size, deterministic)
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for element in value:
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encode_value(write, element, deterministic)
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return EncodePackedField
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elif is_repeated:
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tag_bytes = TagBytes(field_number, wire_type)
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def EncodeRepeatedField(write, value, deterministic):
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for element in value:
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write(tag_bytes)
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encode_value(write, element, deterministic)
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return EncodeRepeatedField
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else:
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tag_bytes = TagBytes(field_number, wire_type)
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def EncodeField(write, value, deterministic):
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write(tag_bytes)
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return encode_value(write, value, deterministic)
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return EncodeField
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return SpecificEncoder
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def _ModifiedEncoder(wire_type, encode_value, compute_value_size, modify_value):
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"""Like SimpleEncoder but additionally invokes modify_value on every value
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before passing it to encode_value. Usually modify_value is ZigZagEncode."""
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def SpecificEncoder(field_number, is_repeated, is_packed):
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if is_packed:
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tag_bytes = TagBytes(field_number, wire_format.WIRETYPE_LENGTH_DELIMITED)
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local_EncodeVarint = _EncodeVarint
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def EncodePackedField(write, value, deterministic):
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write(tag_bytes)
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size = 0
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for element in value:
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size += compute_value_size(modify_value(element))
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local_EncodeVarint(write, size, deterministic)
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for element in value:
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encode_value(write, modify_value(element), deterministic)
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return EncodePackedField
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elif is_repeated:
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tag_bytes = TagBytes(field_number, wire_type)
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def EncodeRepeatedField(write, value, deterministic):
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for element in value:
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write(tag_bytes)
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encode_value(write, modify_value(element), deterministic)
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return EncodeRepeatedField
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else:
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tag_bytes = TagBytes(field_number, wire_type)
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def EncodeField(write, value, deterministic):
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write(tag_bytes)
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return encode_value(write, modify_value(value), deterministic)
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return EncodeField
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return SpecificEncoder
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def _StructPackEncoder(wire_type, format):
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"""Return a constructor for an encoder for a fixed-width field.
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Args:
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wire_type: The field's wire type, for encoding tags.
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format: The format string to pass to struct.pack().
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"""
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value_size = struct.calcsize(format)
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def SpecificEncoder(field_number, is_repeated, is_packed):
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local_struct_pack = struct.pack
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if is_packed:
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tag_bytes = TagBytes(field_number, wire_format.WIRETYPE_LENGTH_DELIMITED)
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local_EncodeVarint = _EncodeVarint
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def EncodePackedField(write, value, deterministic):
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write(tag_bytes)
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local_EncodeVarint(write, len(value) * value_size, deterministic)
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for element in value:
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write(local_struct_pack(format, element))
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return EncodePackedField
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elif is_repeated:
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tag_bytes = TagBytes(field_number, wire_type)
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def EncodeRepeatedField(write, value, unused_deterministic=None):
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for element in value:
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write(tag_bytes)
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write(local_struct_pack(format, element))
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return EncodeRepeatedField
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else:
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tag_bytes = TagBytes(field_number, wire_type)
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def EncodeField(write, value, unused_deterministic=None):
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write(tag_bytes)
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return write(local_struct_pack(format, value))
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return EncodeField
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return SpecificEncoder
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def _FloatingPointEncoder(wire_type, format):
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"""Return a constructor for an encoder for float fields.
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This is like StructPackEncoder, but catches errors that may be due to
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passing non-finite floating-point values to struct.pack, and makes a
|
|
second attempt to encode those values.
|
|
|
|
Args:
|
|
wire_type: The field's wire type, for encoding tags.
|
|
format: The format string to pass to struct.pack().
|
|
"""
|
|
|
|
value_size = struct.calcsize(format)
|
|
if value_size == 4:
|
|
def EncodeNonFiniteOrRaise(write, value):
|
|
# Remember that the serialized form uses little-endian byte order.
|
|
if value == _POS_INF:
|
|
write(b'\x00\x00\x80\x7F')
|
|
elif value == _NEG_INF:
|
|
write(b'\x00\x00\x80\xFF')
|
|
elif value != value: # NaN
|
|
write(b'\x00\x00\xC0\x7F')
|
|
else:
|
|
raise
|
|
elif value_size == 8:
|
|
def EncodeNonFiniteOrRaise(write, value):
|
|
if value == _POS_INF:
|
|
write(b'\x00\x00\x00\x00\x00\x00\xF0\x7F')
|
|
elif value == _NEG_INF:
|
|
write(b'\x00\x00\x00\x00\x00\x00\xF0\xFF')
|
|
elif value != value: # NaN
|
|
write(b'\x00\x00\x00\x00\x00\x00\xF8\x7F')
|
|
else:
|
|
raise
|
|
else:
|
|
raise ValueError('Can\'t encode floating-point values that are '
|
|
'%d bytes long (only 4 or 8)' % value_size)
|
|
|
|
def SpecificEncoder(field_number, is_repeated, is_packed):
|
|
local_struct_pack = struct.pack
|
|
if is_packed:
|
|
tag_bytes = TagBytes(field_number, wire_format.WIRETYPE_LENGTH_DELIMITED)
|
|
local_EncodeVarint = _EncodeVarint
|
|
def EncodePackedField(write, value, deterministic):
|
|
write(tag_bytes)
|
|
local_EncodeVarint(write, len(value) * value_size, deterministic)
|
|
for element in value:
|
|
# This try/except block is going to be faster than any code that
|
|
# we could write to check whether element is finite.
|
|
try:
|
|
write(local_struct_pack(format, element))
|
|
except SystemError:
|
|
EncodeNonFiniteOrRaise(write, element)
|
|
return EncodePackedField
|
|
elif is_repeated:
|
|
tag_bytes = TagBytes(field_number, wire_type)
|
|
def EncodeRepeatedField(write, value, unused_deterministic=None):
|
|
for element in value:
|
|
write(tag_bytes)
|
|
try:
|
|
write(local_struct_pack(format, element))
|
|
except SystemError:
|
|
EncodeNonFiniteOrRaise(write, element)
|
|
return EncodeRepeatedField
|
|
else:
|
|
tag_bytes = TagBytes(field_number, wire_type)
|
|
def EncodeField(write, value, unused_deterministic=None):
|
|
write(tag_bytes)
|
|
try:
|
|
write(local_struct_pack(format, value))
|
|
except SystemError:
|
|
EncodeNonFiniteOrRaise(write, value)
|
|
return EncodeField
|
|
|
|
return SpecificEncoder
|
|
|
|
|
|
# ====================================================================
|
|
# Here we declare an encoder constructor for each field type. These work
|
|
# very similarly to sizer constructors, described earlier.
|
|
|
|
|
|
Int32Encoder = Int64Encoder = EnumEncoder = _SimpleEncoder(
|
|
wire_format.WIRETYPE_VARINT, _EncodeSignedVarint, _SignedVarintSize)
|
|
|
|
UInt32Encoder = UInt64Encoder = _SimpleEncoder(
|
|
wire_format.WIRETYPE_VARINT, _EncodeVarint, _VarintSize)
|
|
|
|
SInt32Encoder = SInt64Encoder = _ModifiedEncoder(
|
|
wire_format.WIRETYPE_VARINT, _EncodeVarint, _VarintSize,
|
|
wire_format.ZigZagEncode)
|
|
|
|
# Note that Python conveniently guarantees that when using the '<' prefix on
|
|
# formats, they will also have the same size across all platforms (as opposed
|
|
# to without the prefix, where their sizes depend on the C compiler's basic
|
|
# type sizes).
|
|
Fixed32Encoder = _StructPackEncoder(wire_format.WIRETYPE_FIXED32, '<I')
|
|
Fixed64Encoder = _StructPackEncoder(wire_format.WIRETYPE_FIXED64, '<Q')
|
|
SFixed32Encoder = _StructPackEncoder(wire_format.WIRETYPE_FIXED32, '<i')
|
|
SFixed64Encoder = _StructPackEncoder(wire_format.WIRETYPE_FIXED64, '<q')
|
|
FloatEncoder = _FloatingPointEncoder(wire_format.WIRETYPE_FIXED32, '<f')
|
|
DoubleEncoder = _FloatingPointEncoder(wire_format.WIRETYPE_FIXED64, '<d')
|
|
|
|
|
|
def BoolEncoder(field_number, is_repeated, is_packed):
|
|
"""Returns an encoder for a boolean field."""
|
|
|
|
false_byte = b'\x00'
|
|
true_byte = b'\x01'
|
|
if is_packed:
|
|
tag_bytes = TagBytes(field_number, wire_format.WIRETYPE_LENGTH_DELIMITED)
|
|
local_EncodeVarint = _EncodeVarint
|
|
def EncodePackedField(write, value, deterministic):
|
|
write(tag_bytes)
|
|
local_EncodeVarint(write, len(value), deterministic)
|
|
for element in value:
|
|
if element:
|
|
write(true_byte)
|
|
else:
|
|
write(false_byte)
|
|
return EncodePackedField
|
|
elif is_repeated:
|
|
tag_bytes = TagBytes(field_number, wire_format.WIRETYPE_VARINT)
|
|
def EncodeRepeatedField(write, value, unused_deterministic=None):
|
|
for element in value:
|
|
write(tag_bytes)
|
|
if element:
|
|
write(true_byte)
|
|
else:
|
|
write(false_byte)
|
|
return EncodeRepeatedField
|
|
else:
|
|
tag_bytes = TagBytes(field_number, wire_format.WIRETYPE_VARINT)
|
|
def EncodeField(write, value, unused_deterministic=None):
|
|
write(tag_bytes)
|
|
if value:
|
|
return write(true_byte)
|
|
return write(false_byte)
|
|
return EncodeField
|
|
|
|
|
|
def StringEncoder(field_number, is_repeated, is_packed):
|
|
"""Returns an encoder for a string field."""
|
|
|
|
tag = TagBytes(field_number, wire_format.WIRETYPE_LENGTH_DELIMITED)
|
|
local_EncodeVarint = _EncodeVarint
|
|
local_len = len
|
|
assert not is_packed
|
|
if is_repeated:
|
|
def EncodeRepeatedField(write, value, deterministic):
|
|
for element in value:
|
|
encoded = element.encode('utf-8')
|
|
write(tag)
|
|
local_EncodeVarint(write, local_len(encoded), deterministic)
|
|
write(encoded)
|
|
return EncodeRepeatedField
|
|
else:
|
|
def EncodeField(write, value, deterministic):
|
|
encoded = value.encode('utf-8')
|
|
write(tag)
|
|
local_EncodeVarint(write, local_len(encoded), deterministic)
|
|
return write(encoded)
|
|
return EncodeField
|
|
|
|
|
|
def BytesEncoder(field_number, is_repeated, is_packed):
|
|
"""Returns an encoder for a bytes field."""
|
|
|
|
tag = TagBytes(field_number, wire_format.WIRETYPE_LENGTH_DELIMITED)
|
|
local_EncodeVarint = _EncodeVarint
|
|
local_len = len
|
|
assert not is_packed
|
|
if is_repeated:
|
|
def EncodeRepeatedField(write, value, deterministic):
|
|
for element in value:
|
|
write(tag)
|
|
local_EncodeVarint(write, local_len(element), deterministic)
|
|
write(element)
|
|
return EncodeRepeatedField
|
|
else:
|
|
def EncodeField(write, value, deterministic):
|
|
write(tag)
|
|
local_EncodeVarint(write, local_len(value), deterministic)
|
|
return write(value)
|
|
return EncodeField
|
|
|
|
|
|
def GroupEncoder(field_number, is_repeated, is_packed):
|
|
"""Returns an encoder for a group field."""
|
|
|
|
start_tag = TagBytes(field_number, wire_format.WIRETYPE_START_GROUP)
|
|
end_tag = TagBytes(field_number, wire_format.WIRETYPE_END_GROUP)
|
|
assert not is_packed
|
|
if is_repeated:
|
|
def EncodeRepeatedField(write, value, deterministic):
|
|
for element in value:
|
|
write(start_tag)
|
|
element._InternalSerialize(write, deterministic)
|
|
write(end_tag)
|
|
return EncodeRepeatedField
|
|
else:
|
|
def EncodeField(write, value, deterministic):
|
|
write(start_tag)
|
|
value._InternalSerialize(write, deterministic)
|
|
return write(end_tag)
|
|
return EncodeField
|
|
|
|
|
|
def MessageEncoder(field_number, is_repeated, is_packed):
|
|
"""Returns an encoder for a message field."""
|
|
|
|
tag = TagBytes(field_number, wire_format.WIRETYPE_LENGTH_DELIMITED)
|
|
local_EncodeVarint = _EncodeVarint
|
|
assert not is_packed
|
|
if is_repeated:
|
|
def EncodeRepeatedField(write, value, deterministic):
|
|
for element in value:
|
|
write(tag)
|
|
local_EncodeVarint(write, element.ByteSize(), deterministic)
|
|
element._InternalSerialize(write, deterministic)
|
|
return EncodeRepeatedField
|
|
else:
|
|
def EncodeField(write, value, deterministic):
|
|
write(tag)
|
|
local_EncodeVarint(write, value.ByteSize(), deterministic)
|
|
return value._InternalSerialize(write, deterministic)
|
|
return EncodeField
|
|
|
|
|
|
# --------------------------------------------------------------------
|
|
# As before, MessageSet is special.
|
|
|
|
|
|
def MessageSetItemEncoder(field_number):
|
|
"""Encoder for extensions of MessageSet.
|
|
|
|
The message set message looks like this:
|
|
message MessageSet {
|
|
repeated group Item = 1 {
|
|
required int32 type_id = 2;
|
|
required string message = 3;
|
|
}
|
|
}
|
|
"""
|
|
start_bytes = b"".join([
|
|
TagBytes(1, wire_format.WIRETYPE_START_GROUP),
|
|
TagBytes(2, wire_format.WIRETYPE_VARINT),
|
|
_VarintBytes(field_number),
|
|
TagBytes(3, wire_format.WIRETYPE_LENGTH_DELIMITED)])
|
|
end_bytes = TagBytes(1, wire_format.WIRETYPE_END_GROUP)
|
|
local_EncodeVarint = _EncodeVarint
|
|
|
|
def EncodeField(write, value, deterministic):
|
|
write(start_bytes)
|
|
local_EncodeVarint(write, value.ByteSize(), deterministic)
|
|
value._InternalSerialize(write, deterministic)
|
|
return write(end_bytes)
|
|
|
|
return EncodeField
|
|
|
|
|
|
# --------------------------------------------------------------------
|
|
# As before, Map is special.
|
|
|
|
|
|
def MapEncoder(field_descriptor):
|
|
"""Encoder for extensions of MessageSet.
|
|
|
|
Maps always have a wire format like this:
|
|
message MapEntry {
|
|
key_type key = 1;
|
|
value_type value = 2;
|
|
}
|
|
repeated MapEntry map = N;
|
|
"""
|
|
# Can't look at field_descriptor.message_type._concrete_class because it may
|
|
# not have been initialized yet.
|
|
message_type = field_descriptor.message_type
|
|
encode_message = MessageEncoder(field_descriptor.number, False, False)
|
|
|
|
def EncodeField(write, value, deterministic):
|
|
value_keys = sorted(value.keys()) if deterministic else value
|
|
for key in value_keys:
|
|
entry_msg = message_type._concrete_class(key=key, value=value[key])
|
|
encode_message(write, entry_msg, deterministic)
|
|
|
|
return EncodeField
|