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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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Chromium Code Reviews
Issue 1162993005:
Renamed google.protobuf to protobuf26 (Closed)
Base URL: svn://svn.chromium.org/chrome/trunk/tools/depot_tools