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Side by Side Diff: third_party/google/protobuf/internal/wire_format.py

Issue 1153333003: Added tools to retrieve CQ builders from a CQ config (Closed) Base URL: https://chromium.googlesource.com/chromium/tools/depot_tools.git@master
Patch Set: Addressed comments Created 5 years, 6 months ago
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1 # Protocol Buffers - Google's data interchange format
2 # Copyright 2008 Google Inc. All rights reserved.
3 # http://code.google.com/p/protobuf/
4 #
5 # Redistribution and use in source and binary forms, with or without
6 # modification, are permitted provided that the following conditions are
7 # met:
8 #
9 # * Redistributions of source code must retain the above copyright
10 # notice, this list of conditions and the following disclaimer.
11 # * Redistributions in binary form must reproduce the above
12 # copyright notice, this list of conditions and the following disclaimer
13 # in the documentation and/or other materials provided with the
14 # distribution.
15 # * Neither the name of Google Inc. nor the names of its
16 # contributors may be used to endorse or promote products derived from
17 # this software without specific prior written permission.
18 #
19 # THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
20 # "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
21 # LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
22 # A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
23 # OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
24 # SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
25 # LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
26 # DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
27 # THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
28 # (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
29 # OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
30
31 """Constants and static functions to support protocol buffer wire format."""
32
33 __author__ = 'robinson@google.com (Will Robinson)'
34
35 import struct
36 from google.protobuf import descriptor
37 from google.protobuf import message
38
39
40 TAG_TYPE_BITS = 3 # Number of bits used to hold type info in a proto tag.
41 TAG_TYPE_MASK = (1 << TAG_TYPE_BITS) - 1 # 0x7
42
43 # These numbers identify the wire type of a protocol buffer value.
44 # We use the least-significant TAG_TYPE_BITS bits of the varint-encoded
45 # tag-and-type to store one of these WIRETYPE_* constants.
46 # These values must match WireType enum in google/protobuf/wire_format.h.
47 WIRETYPE_VARINT = 0
48 WIRETYPE_FIXED64 = 1
49 WIRETYPE_LENGTH_DELIMITED = 2
50 WIRETYPE_START_GROUP = 3
51 WIRETYPE_END_GROUP = 4
52 WIRETYPE_FIXED32 = 5
53 _WIRETYPE_MAX = 5
54
55
56 # Bounds for various integer types.
57 INT32_MAX = int((1 << 31) - 1)
58 INT32_MIN = int(-(1 << 31))
59 UINT32_MAX = (1 << 32) - 1
60
61 INT64_MAX = (1 << 63) - 1
62 INT64_MIN = -(1 << 63)
63 UINT64_MAX = (1 << 64) - 1
64
65 # "struct" format strings that will encode/decode the specified formats.
66 FORMAT_UINT32_LITTLE_ENDIAN = '<I'
67 FORMAT_UINT64_LITTLE_ENDIAN = '<Q'
68 FORMAT_FLOAT_LITTLE_ENDIAN = '<f'
69 FORMAT_DOUBLE_LITTLE_ENDIAN = '<d'
70
71
72 # We'll have to provide alternate implementations of AppendLittleEndian*() on
73 # any architectures where these checks fail.
74 if struct.calcsize(FORMAT_UINT32_LITTLE_ENDIAN) != 4:
75 raise AssertionError('Format "I" is not a 32-bit number.')
76 if struct.calcsize(FORMAT_UINT64_LITTLE_ENDIAN) != 8:
77 raise AssertionError('Format "Q" is not a 64-bit number.')
78
79
80 def PackTag(field_number, wire_type):
81 """Returns an unsigned 32-bit integer that encodes the field number and
82 wire type information in standard protocol message wire format.
83
84 Args:
85 field_number: Expected to be an integer in the range [1, 1 << 29)
86 wire_type: One of the WIRETYPE_* constants.
87 """
88 if not 0 <= wire_type <= _WIRETYPE_MAX:
89 raise message.EncodeError('Unknown wire type: %d' % wire_type)
90 return (field_number << TAG_TYPE_BITS) | wire_type
91
92
93 def UnpackTag(tag):
94 """The inverse of PackTag(). Given an unsigned 32-bit number,
95 returns a (field_number, wire_type) tuple.
96 """
97 return (tag >> TAG_TYPE_BITS), (tag & TAG_TYPE_MASK)
98
99
100 def ZigZagEncode(value):
101 """ZigZag Transform: Encodes signed integers so that they can be
102 effectively used with varint encoding. See wire_format.h for
103 more details.
104 """
105 if value >= 0:
106 return value << 1
107 return (value << 1) ^ (~0)
108
109
110 def ZigZagDecode(value):
111 """Inverse of ZigZagEncode()."""
112 if not value & 0x1:
113 return value >> 1
114 return (value >> 1) ^ (~0)
115
116
117
118 # The *ByteSize() functions below return the number of bytes required to
119 # serialize "field number + type" information and then serialize the value.
120
121
122 def Int32ByteSize(field_number, int32):
123 return Int64ByteSize(field_number, int32)
124
125
126 def Int32ByteSizeNoTag(int32):
127 return _VarUInt64ByteSizeNoTag(0xffffffffffffffff & int32)
128
129
130 def Int64ByteSize(field_number, int64):
131 # Have to convert to uint before calling UInt64ByteSize().
132 return UInt64ByteSize(field_number, 0xffffffffffffffff & int64)
133
134
135 def UInt32ByteSize(field_number, uint32):
136 return UInt64ByteSize(field_number, uint32)
137
138
139 def UInt64ByteSize(field_number, uint64):
140 return TagByteSize(field_number) + _VarUInt64ByteSizeNoTag(uint64)
141
142
143 def SInt32ByteSize(field_number, int32):
144 return UInt32ByteSize(field_number, ZigZagEncode(int32))
145
146
147 def SInt64ByteSize(field_number, int64):
148 return UInt64ByteSize(field_number, ZigZagEncode(int64))
149
150
151 def Fixed32ByteSize(field_number, fixed32):
152 return TagByteSize(field_number) + 4
153
154
155 def Fixed64ByteSize(field_number, fixed64):
156 return TagByteSize(field_number) + 8
157
158
159 def SFixed32ByteSize(field_number, sfixed32):
160 return TagByteSize(field_number) + 4
161
162
163 def SFixed64ByteSize(field_number, sfixed64):
164 return TagByteSize(field_number) + 8
165
166
167 def FloatByteSize(field_number, flt):
168 return TagByteSize(field_number) + 4
169
170
171 def DoubleByteSize(field_number, double):
172 return TagByteSize(field_number) + 8
173
174
175 def BoolByteSize(field_number, b):
176 return TagByteSize(field_number) + 1
177
178
179 def EnumByteSize(field_number, enum):
180 return UInt32ByteSize(field_number, enum)
181
182
183 def StringByteSize(field_number, string):
184 return BytesByteSize(field_number, string.encode('utf-8'))
185
186
187 def BytesByteSize(field_number, b):
188 return (TagByteSize(field_number)
189 + _VarUInt64ByteSizeNoTag(len(b))
190 + len(b))
191
192
193 def GroupByteSize(field_number, message):
194 return (2 * TagByteSize(field_number) # START and END group.
195 + message.ByteSize())
196
197
198 def MessageByteSize(field_number, message):
199 return (TagByteSize(field_number)
200 + _VarUInt64ByteSizeNoTag(message.ByteSize())
201 + message.ByteSize())
202
203
204 def MessageSetItemByteSize(field_number, msg):
205 # First compute the sizes of the tags.
206 # There are 2 tags for the beginning and ending of the repeated group, that
207 # is field number 1, one with field number 2 (type_id) and one with field
208 # number 3 (message).
209 total_size = (2 * TagByteSize(1) + TagByteSize(2) + TagByteSize(3))
210
211 # Add the number of bytes for type_id.
212 total_size += _VarUInt64ByteSizeNoTag(field_number)
213
214 message_size = msg.ByteSize()
215
216 # The number of bytes for encoding the length of the message.
217 total_size += _VarUInt64ByteSizeNoTag(message_size)
218
219 # The size of the message.
220 total_size += message_size
221 return total_size
222
223
224 def TagByteSize(field_number):
225 """Returns the bytes required to serialize a tag with this field number."""
226 # Just pass in type 0, since the type won't affect the tag+type size.
227 return _VarUInt64ByteSizeNoTag(PackTag(field_number, 0))
228
229
230 # Private helper function for the *ByteSize() functions above.
231
232 def _VarUInt64ByteSizeNoTag(uint64):
233 """Returns the number of bytes required to serialize a single varint
234 using boundary value comparisons. (unrolled loop optimization -WPierce)
235 uint64 must be unsigned.
236 """
237 if uint64 <= 0x7f: return 1
238 if uint64 <= 0x3fff: return 2
239 if uint64 <= 0x1fffff: return 3
240 if uint64 <= 0xfffffff: return 4
241 if uint64 <= 0x7ffffffff: return 5
242 if uint64 <= 0x3ffffffffff: return 6
243 if uint64 <= 0x1ffffffffffff: return 7
244 if uint64 <= 0xffffffffffffff: return 8
245 if uint64 <= 0x7fffffffffffffff: return 9
246 if uint64 > UINT64_MAX:
247 raise message.EncodeError('Value out of range: %d' % uint64)
248 return 10
249
250
251 NON_PACKABLE_TYPES = (
252 descriptor.FieldDescriptor.TYPE_STRING,
253 descriptor.FieldDescriptor.TYPE_GROUP,
254 descriptor.FieldDescriptor.TYPE_MESSAGE,
255 descriptor.FieldDescriptor.TYPE_BYTES
256 )
257
258
259 def IsTypePackable(field_type):
260 """Return true iff packable = true is valid for fields of this type.
261
262 Args:
263 field_type: a FieldDescriptor::Type value.
264
265 Returns:
266 True iff fields of this type are packable.
267 """
268 return field_type not in NON_PACKABLE_TYPES
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