1// Go support for Protocol Buffers - Google's data interchange format 2// 3// Copyright 2010 The Go Authors. All rights reserved. 4// https://github.com/golang/protobuf 5// 6// Redistribution and use in source and binary forms, with or without 7// modification, are permitted provided that the following conditions are 8// met: 9// 10// * Redistributions of source code must retain the above copyright 11// notice, this list of conditions and the following disclaimer. 12// * Redistributions in binary form must reproduce the above 13// copyright notice, this list of conditions and the following disclaimer 14// in the documentation and/or other materials provided with the 15// distribution. 16// * Neither the name of Google Inc. nor the names of its 17// contributors may be used to endorse or promote products derived from 18// this software without specific prior written permission. 19// 20// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS 21// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT 22// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR 23// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT 24// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, 25// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT 26// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 27// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 28// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 29// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE 30// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 31 32package proto 33 34/* 35 * Routines for decoding protocol buffer data to construct in-memory representations. 36 */ 37 38import ( 39 "errors" 40 "fmt" 41 "io" 42) 43 44// errOverflow is returned when an integer is too large to be represented. 45var errOverflow = errors.New("proto: integer overflow") 46 47// ErrInternalBadWireType is returned by generated code when an incorrect 48// wire type is encountered. It does not get returned to user code. 49var ErrInternalBadWireType = errors.New("proto: internal error: bad wiretype for oneof") 50 51// DecodeVarint reads a varint-encoded integer from the slice. 52// It returns the integer and the number of bytes consumed, or 53// zero if there is not enough. 54// This is the format for the 55// int32, int64, uint32, uint64, bool, and enum 56// protocol buffer types. 57func DecodeVarint(buf []byte) (x uint64, n int) { 58 for shift := uint(0); shift < 64; shift += 7 { 59 if n >= len(buf) { 60 return 0, 0 61 } 62 b := uint64(buf[n]) 63 n++ 64 x |= (b & 0x7F) << shift 65 if (b & 0x80) == 0 { 66 return x, n 67 } 68 } 69 70 // The number is too large to represent in a 64-bit value. 71 return 0, 0 72} 73 74func (p *Buffer) decodeVarintSlow() (x uint64, err error) { 75 i := p.index 76 l := len(p.buf) 77 78 for shift := uint(0); shift < 64; shift += 7 { 79 if i >= l { 80 err = io.ErrUnexpectedEOF 81 return 82 } 83 b := p.buf[i] 84 i++ 85 x |= (uint64(b) & 0x7F) << shift 86 if b < 0x80 { 87 p.index = i 88 return 89 } 90 } 91 92 // The number is too large to represent in a 64-bit value. 93 err = errOverflow 94 return 95} 96 97// DecodeVarint reads a varint-encoded integer from the Buffer. 98// This is the format for the 99// int32, int64, uint32, uint64, bool, and enum 100// protocol buffer types. 101func (p *Buffer) DecodeVarint() (x uint64, err error) { 102 i := p.index 103 buf := p.buf 104 105 if i >= len(buf) { 106 return 0, io.ErrUnexpectedEOF 107 } else if buf[i] < 0x80 { 108 p.index++ 109 return uint64(buf[i]), nil 110 } else if len(buf)-i < 10 { 111 return p.decodeVarintSlow() 112 } 113 114 var b uint64 115 // we already checked the first byte 116 x = uint64(buf[i]) - 0x80 117 i++ 118 119 b = uint64(buf[i]) 120 i++ 121 x += b << 7 122 if b&0x80 == 0 { 123 goto done 124 } 125 x -= 0x80 << 7 126 127 b = uint64(buf[i]) 128 i++ 129 x += b << 14 130 if b&0x80 == 0 { 131 goto done 132 } 133 x -= 0x80 << 14 134 135 b = uint64(buf[i]) 136 i++ 137 x += b << 21 138 if b&0x80 == 0 { 139 goto done 140 } 141 x -= 0x80 << 21 142 143 b = uint64(buf[i]) 144 i++ 145 x += b << 28 146 if b&0x80 == 0 { 147 goto done 148 } 149 x -= 0x80 << 28 150 151 b = uint64(buf[i]) 152 i++ 153 x += b << 35 154 if b&0x80 == 0 { 155 goto done 156 } 157 x -= 0x80 << 35 158 159 b = uint64(buf[i]) 160 i++ 161 x += b << 42 162 if b&0x80 == 0 { 163 goto done 164 } 165 x -= 0x80 << 42 166 167 b = uint64(buf[i]) 168 i++ 169 x += b << 49 170 if b&0x80 == 0 { 171 goto done 172 } 173 x -= 0x80 << 49 174 175 b = uint64(buf[i]) 176 i++ 177 x += b << 56 178 if b&0x80 == 0 { 179 goto done 180 } 181 x -= 0x80 << 56 182 183 b = uint64(buf[i]) 184 i++ 185 x += b << 63 186 if b&0x80 == 0 { 187 goto done 188 } 189 190 return 0, errOverflow 191 192done: 193 p.index = i 194 return x, nil 195} 196 197// DecodeFixed64 reads a 64-bit integer from the Buffer. 198// This is the format for the 199// fixed64, sfixed64, and double protocol buffer types. 200func (p *Buffer) DecodeFixed64() (x uint64, err error) { 201 // x, err already 0 202 i := p.index + 8 203 if i < 0 || i > len(p.buf) { 204 err = io.ErrUnexpectedEOF 205 return 206 } 207 p.index = i 208 209 x = uint64(p.buf[i-8]) 210 x |= uint64(p.buf[i-7]) << 8 211 x |= uint64(p.buf[i-6]) << 16 212 x |= uint64(p.buf[i-5]) << 24 213 x |= uint64(p.buf[i-4]) << 32 214 x |= uint64(p.buf[i-3]) << 40 215 x |= uint64(p.buf[i-2]) << 48 216 x |= uint64(p.buf[i-1]) << 56 217 return 218} 219 220// DecodeFixed32 reads a 32-bit integer from the Buffer. 221// This is the format for the 222// fixed32, sfixed32, and float protocol buffer types. 223func (p *Buffer) DecodeFixed32() (x uint64, err error) { 224 // x, err already 0 225 i := p.index + 4 226 if i < 0 || i > len(p.buf) { 227 err = io.ErrUnexpectedEOF 228 return 229 } 230 p.index = i 231 232 x = uint64(p.buf[i-4]) 233 x |= uint64(p.buf[i-3]) << 8 234 x |= uint64(p.buf[i-2]) << 16 235 x |= uint64(p.buf[i-1]) << 24 236 return 237} 238 239// DecodeZigzag64 reads a zigzag-encoded 64-bit integer 240// from the Buffer. 241// This is the format used for the sint64 protocol buffer type. 242func (p *Buffer) DecodeZigzag64() (x uint64, err error) { 243 x, err = p.DecodeVarint() 244 if err != nil { 245 return 246 } 247 x = (x >> 1) ^ uint64((int64(x&1)<<63)>>63) 248 return 249} 250 251// DecodeZigzag32 reads a zigzag-encoded 32-bit integer 252// from the Buffer. 253// This is the format used for the sint32 protocol buffer type. 254func (p *Buffer) DecodeZigzag32() (x uint64, err error) { 255 x, err = p.DecodeVarint() 256 if err != nil { 257 return 258 } 259 x = uint64((uint32(x) >> 1) ^ uint32((int32(x&1)<<31)>>31)) 260 return 261} 262 263// DecodeRawBytes reads a count-delimited byte buffer from the Buffer. 264// This is the format used for the bytes protocol buffer 265// type and for embedded messages. 266func (p *Buffer) DecodeRawBytes(alloc bool) (buf []byte, err error) { 267 n, err := p.DecodeVarint() 268 if err != nil { 269 return nil, err 270 } 271 272 nb := int(n) 273 if nb < 0 { 274 return nil, fmt.Errorf("proto: bad byte length %d", nb) 275 } 276 end := p.index + nb 277 if end < p.index || end > len(p.buf) { 278 return nil, io.ErrUnexpectedEOF 279 } 280 281 if !alloc { 282 // todo: check if can get more uses of alloc=false 283 buf = p.buf[p.index:end] 284 p.index += nb 285 return 286 } 287 288 buf = make([]byte, nb) 289 copy(buf, p.buf[p.index:]) 290 p.index += nb 291 return 292} 293 294// DecodeStringBytes reads an encoded string from the Buffer. 295// This is the format used for the proto2 string type. 296func (p *Buffer) DecodeStringBytes() (s string, err error) { 297 buf, err := p.DecodeRawBytes(false) 298 if err != nil { 299 return 300 } 301 return string(buf), nil 302} 303 304// Unmarshaler is the interface representing objects that can 305// unmarshal themselves. The argument points to data that may be 306// overwritten, so implementations should not keep references to the 307// buffer. 308// Unmarshal implementations should not clear the receiver. 309// Any unmarshaled data should be merged into the receiver. 310// Callers of Unmarshal that do not want to retain existing data 311// should Reset the receiver before calling Unmarshal. 312type Unmarshaler interface { 313 Unmarshal([]byte) error 314} 315 316// newUnmarshaler is the interface representing objects that can 317// unmarshal themselves. The semantics are identical to Unmarshaler. 318// 319// This exists to support protoc-gen-go generated messages. 320// The proto package will stop type-asserting to this interface in the future. 321// 322// DO NOT DEPEND ON THIS. 323type newUnmarshaler interface { 324 XXX_Unmarshal([]byte) error 325} 326 327// Unmarshal parses the protocol buffer representation in buf and places the 328// decoded result in pb. If the struct underlying pb does not match 329// the data in buf, the results can be unpredictable. 330// 331// Unmarshal resets pb before starting to unmarshal, so any 332// existing data in pb is always removed. Use UnmarshalMerge 333// to preserve and append to existing data. 334func Unmarshal(buf []byte, pb Message) error { 335 pb.Reset() 336 if u, ok := pb.(newUnmarshaler); ok { 337 return u.XXX_Unmarshal(buf) 338 } 339 if u, ok := pb.(Unmarshaler); ok { 340 return u.Unmarshal(buf) 341 } 342 return NewBuffer(buf).Unmarshal(pb) 343} 344 345// UnmarshalMerge parses the protocol buffer representation in buf and 346// writes the decoded result to pb. If the struct underlying pb does not match 347// the data in buf, the results can be unpredictable. 348// 349// UnmarshalMerge merges into existing data in pb. 350// Most code should use Unmarshal instead. 351func UnmarshalMerge(buf []byte, pb Message) error { 352 if u, ok := pb.(newUnmarshaler); ok { 353 return u.XXX_Unmarshal(buf) 354 } 355 if u, ok := pb.(Unmarshaler); ok { 356 // NOTE: The history of proto have unfortunately been inconsistent 357 // whether Unmarshaler should or should not implicitly clear itself. 358 // Some implementations do, most do not. 359 // Thus, calling this here may or may not do what people want. 360 // 361 // See https://github.com/golang/protobuf/issues/424 362 return u.Unmarshal(buf) 363 } 364 return NewBuffer(buf).Unmarshal(pb) 365} 366 367// DecodeMessage reads a count-delimited message from the Buffer. 368func (p *Buffer) DecodeMessage(pb Message) error { 369 enc, err := p.DecodeRawBytes(false) 370 if err != nil { 371 return err 372 } 373 return NewBuffer(enc).Unmarshal(pb) 374} 375 376// DecodeGroup reads a tag-delimited group from the Buffer. 377// StartGroup tag is already consumed. This function consumes 378// EndGroup tag. 379func (p *Buffer) DecodeGroup(pb Message) error { 380 b := p.buf[p.index:] 381 x, y := findEndGroup(b) 382 if x < 0 { 383 return io.ErrUnexpectedEOF 384 } 385 err := Unmarshal(b[:x], pb) 386 p.index += y 387 return err 388} 389 390// Unmarshal parses the protocol buffer representation in the 391// Buffer and places the decoded result in pb. If the struct 392// underlying pb does not match the data in the buffer, the results can be 393// unpredictable. 394// 395// Unlike proto.Unmarshal, this does not reset pb before starting to unmarshal. 396func (p *Buffer) Unmarshal(pb Message) error { 397 // If the object can unmarshal itself, let it. 398 if u, ok := pb.(newUnmarshaler); ok { 399 err := u.XXX_Unmarshal(p.buf[p.index:]) 400 p.index = len(p.buf) 401 return err 402 } 403 if u, ok := pb.(Unmarshaler); ok { 404 // NOTE: The history of proto have unfortunately been inconsistent 405 // whether Unmarshaler should or should not implicitly clear itself. 406 // Some implementations do, most do not. 407 // Thus, calling this here may or may not do what people want. 408 // 409 // See https://github.com/golang/protobuf/issues/424 410 err := u.Unmarshal(p.buf[p.index:]) 411 p.index = len(p.buf) 412 return err 413 } 414 415 // Slow workaround for messages that aren't Unmarshalers. 416 // This includes some hand-coded .pb.go files and 417 // bootstrap protos. 418 // TODO: fix all of those and then add Unmarshal to 419 // the Message interface. Then: 420 // The cast above and code below can be deleted. 421 // The old unmarshaler can be deleted. 422 // Clients can call Unmarshal directly (can already do that, actually). 423 var info InternalMessageInfo 424 err := info.Unmarshal(pb, p.buf[p.index:]) 425 p.index = len(p.buf) 426 return err 427} 428