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| 1 #region Copyright notice and license |
| 2 // Protocol Buffers - Google's data interchange format |
| 3 // Copyright 2008 Google Inc. All rights reserved. |
| 4 // https://developers.google.com/protocol-buffers/ |
| 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 #endregion |
| 32 |
| 33 using Google.Protobuf.Collections; |
| 34 using System; |
| 35 using System.IO; |
| 36 using System.Text; |
| 37 |
| 38 namespace Google.Protobuf |
| 39 { |
| 40 /// <summary> |
| 41 /// Encodes and writes protocol message fields. |
| 42 /// </summary> |
| 43 /// <remarks> |
| 44 /// <para> |
| 45 /// This class is generally used by generated code to write appropriate |
| 46 /// primitives to the stream. It effectively encapsulates the lowest |
| 47 /// levels of protocol buffer format. Unlike some other implementations, |
| 48 /// this does not include combined "write tag and value" methods. Generated |
| 49 /// code knows the exact byte representations of the tags they're going to w
rite, |
| 50 /// so there's no need to re-encode them each time. Manually-written code ca
lling |
| 51 /// this class should just call one of the <c>WriteTag</c> overloads before
each value. |
| 52 /// </para> |
| 53 /// <para> |
| 54 /// Repeated fields and map fields are not handled by this class; use <c>Rep
eatedField<T></c> |
| 55 /// and <c>MapField<TKey, TValue></c> to serialize such fields. |
| 56 /// </para> |
| 57 /// </remarks> |
| 58 public sealed partial class CodedOutputStream |
| 59 { |
| 60 // "Local" copy of Encoding.UTF8, for efficiency. (Yes, it makes a diffe
rence.) |
| 61 internal static readonly Encoding Utf8Encoding = Encoding.UTF8; |
| 62 |
| 63 /// <summary> |
| 64 /// The buffer size used by CreateInstance(Stream). |
| 65 /// </summary> |
| 66 public static readonly int DefaultBufferSize = 4096; |
| 67 |
| 68 private readonly byte[] buffer; |
| 69 private readonly int limit; |
| 70 private int position; |
| 71 private readonly Stream output; |
| 72 |
| 73 #region Construction |
| 74 /// <summary> |
| 75 /// Creates a new CodedOutputStream that writes directly to the given |
| 76 /// byte array. If more bytes are written than fit in the array, |
| 77 /// OutOfSpaceException will be thrown. |
| 78 /// </summary> |
| 79 public CodedOutputStream(byte[] flatArray) : this(flatArray, 0, flatArra
y.Length) |
| 80 { |
| 81 } |
| 82 |
| 83 /// <summary> |
| 84 /// Creates a new CodedOutputStream that writes directly to the given |
| 85 /// byte array slice. If more bytes are written than fit in the array, |
| 86 /// OutOfSpaceException will be thrown. |
| 87 /// </summary> |
| 88 private CodedOutputStream(byte[] buffer, int offset, int length) |
| 89 { |
| 90 this.output = null; |
| 91 this.buffer = buffer; |
| 92 this.position = offset; |
| 93 this.limit = offset + length; |
| 94 } |
| 95 |
| 96 private CodedOutputStream(Stream output, byte[] buffer) |
| 97 { |
| 98 this.output = output; |
| 99 this.buffer = buffer; |
| 100 this.position = 0; |
| 101 this.limit = buffer.Length; |
| 102 } |
| 103 |
| 104 /// <summary> |
| 105 /// Creates a new CodedOutputStream which write to the given stream. |
| 106 /// </summary> |
| 107 public CodedOutputStream(Stream output) : this(output, DefaultBufferSize
) |
| 108 { |
| 109 } |
| 110 |
| 111 /// <summary> |
| 112 /// Creates a new CodedOutputStream which write to the given stream and
uses |
| 113 /// the specified buffer size. |
| 114 /// </summary> |
| 115 public CodedOutputStream(Stream output, int bufferSize) : this(output, n
ew byte[bufferSize]) |
| 116 { |
| 117 } |
| 118 #endregion |
| 119 |
| 120 /// <summary> |
| 121 /// Returns the current position in the stream, or the position in the o
utput buffer |
| 122 /// </summary> |
| 123 public long Position |
| 124 { |
| 125 get |
| 126 { |
| 127 if (output != null) |
| 128 { |
| 129 return output.Position + position; |
| 130 } |
| 131 return position; |
| 132 } |
| 133 } |
| 134 |
| 135 #region Writing of values (not including tags) |
| 136 |
| 137 /// <summary> |
| 138 /// Writes a double field value, without a tag, to the stream. |
| 139 /// </summary> |
| 140 /// <param name="value">The value to write</param> |
| 141 public void WriteDouble(double value) |
| 142 { |
| 143 WriteRawLittleEndian64((ulong)BitConverter.DoubleToInt64Bits(value))
; |
| 144 } |
| 145 |
| 146 /// <summary> |
| 147 /// Writes a float field value, without a tag, to the stream. |
| 148 /// </summary> |
| 149 /// <param name="value">The value to write</param> |
| 150 public void WriteFloat(float value) |
| 151 { |
| 152 byte[] rawBytes = BitConverter.GetBytes(value); |
| 153 if (!BitConverter.IsLittleEndian) |
| 154 { |
| 155 ByteArray.Reverse(rawBytes); |
| 156 } |
| 157 |
| 158 if (limit - position >= 4) |
| 159 { |
| 160 buffer[position++] = rawBytes[0]; |
| 161 buffer[position++] = rawBytes[1]; |
| 162 buffer[position++] = rawBytes[2]; |
| 163 buffer[position++] = rawBytes[3]; |
| 164 } |
| 165 else |
| 166 { |
| 167 WriteRawBytes(rawBytes, 0, 4); |
| 168 } |
| 169 } |
| 170 |
| 171 /// <summary> |
| 172 /// Writes a uint64 field value, without a tag, to the stream. |
| 173 /// </summary> |
| 174 /// <param name="value">The value to write</param> |
| 175 public void WriteUInt64(ulong value) |
| 176 { |
| 177 WriteRawVarint64(value); |
| 178 } |
| 179 |
| 180 /// <summary> |
| 181 /// Writes an int64 field value, without a tag, to the stream. |
| 182 /// </summary> |
| 183 /// <param name="value">The value to write</param> |
| 184 public void WriteInt64(long value) |
| 185 { |
| 186 WriteRawVarint64((ulong) value); |
| 187 } |
| 188 |
| 189 /// <summary> |
| 190 /// Writes an int32 field value, without a tag, to the stream. |
| 191 /// </summary> |
| 192 /// <param name="value">The value to write</param> |
| 193 public void WriteInt32(int value) |
| 194 { |
| 195 if (value >= 0) |
| 196 { |
| 197 WriteRawVarint32((uint) value); |
| 198 } |
| 199 else |
| 200 { |
| 201 // Must sign-extend. |
| 202 WriteRawVarint64((ulong) value); |
| 203 } |
| 204 } |
| 205 |
| 206 /// <summary> |
| 207 /// Writes a fixed64 field value, without a tag, to the stream. |
| 208 /// </summary> |
| 209 /// <param name="value">The value to write</param> |
| 210 public void WriteFixed64(ulong value) |
| 211 { |
| 212 WriteRawLittleEndian64(value); |
| 213 } |
| 214 |
| 215 /// <summary> |
| 216 /// Writes a fixed32 field value, without a tag, to the stream. |
| 217 /// </summary> |
| 218 /// <param name="value">The value to write</param> |
| 219 public void WriteFixed32(uint value) |
| 220 { |
| 221 WriteRawLittleEndian32(value); |
| 222 } |
| 223 |
| 224 /// <summary> |
| 225 /// Writes a bool field value, without a tag, to the stream. |
| 226 /// </summary> |
| 227 /// <param name="value">The value to write</param> |
| 228 public void WriteBool(bool value) |
| 229 { |
| 230 WriteRawByte(value ? (byte) 1 : (byte) 0); |
| 231 } |
| 232 |
| 233 /// <summary> |
| 234 /// Writes a string field value, without a tag, to the stream. |
| 235 /// The data is length-prefixed. |
| 236 /// </summary> |
| 237 /// <param name="value">The value to write</param> |
| 238 public void WriteString(string value) |
| 239 { |
| 240 // Optimise the case where we have enough space to write |
| 241 // the string directly to the buffer, which should be common. |
| 242 int length = Utf8Encoding.GetByteCount(value); |
| 243 WriteLength(length); |
| 244 if (limit - position >= length) |
| 245 { |
| 246 if (length == value.Length) // Must be all ASCII... |
| 247 { |
| 248 for (int i = 0; i < length; i++) |
| 249 { |
| 250 buffer[position + i] = (byte)value[i]; |
| 251 } |
| 252 } |
| 253 else |
| 254 { |
| 255 Utf8Encoding.GetBytes(value, 0, value.Length, buffer, positi
on); |
| 256 } |
| 257 position += length; |
| 258 } |
| 259 else |
| 260 { |
| 261 byte[] bytes = Utf8Encoding.GetBytes(value); |
| 262 WriteRawBytes(bytes); |
| 263 } |
| 264 } |
| 265 |
| 266 /// <summary> |
| 267 /// Writes a message, without a tag, to the stream. |
| 268 /// The data is length-prefixed. |
| 269 /// </summary> |
| 270 /// <param name="value">The value to write</param> |
| 271 public void WriteMessage(IMessage value) |
| 272 { |
| 273 WriteLength(value.CalculateSize()); |
| 274 value.WriteTo(this); |
| 275 } |
| 276 |
| 277 /// <summary> |
| 278 /// Write a byte string, without a tag, to the stream. |
| 279 /// The data is length-prefixed. |
| 280 /// </summary> |
| 281 /// <param name="value">The value to write</param> |
| 282 public void WriteBytes(ByteString value) |
| 283 { |
| 284 WriteLength(value.Length); |
| 285 value.WriteRawBytesTo(this); |
| 286 } |
| 287 |
| 288 /// <summary> |
| 289 /// Writes a uint32 value, without a tag, to the stream. |
| 290 /// </summary> |
| 291 /// <param name="value">The value to write</param> |
| 292 public void WriteUInt32(uint value) |
| 293 { |
| 294 WriteRawVarint32(value); |
| 295 } |
| 296 |
| 297 /// <summary> |
| 298 /// Writes an enum value, without a tag, to the stream. |
| 299 /// </summary> |
| 300 /// <param name="value">The value to write</param> |
| 301 public void WriteEnum(int value) |
| 302 { |
| 303 WriteInt32(value); |
| 304 } |
| 305 |
| 306 /// <summary> |
| 307 /// Writes an sfixed32 value, without a tag, to the stream. |
| 308 /// </summary> |
| 309 /// <param name="value">The value to write.</param> |
| 310 public void WriteSFixed32(int value) |
| 311 { |
| 312 WriteRawLittleEndian32((uint) value); |
| 313 } |
| 314 |
| 315 /// <summary> |
| 316 /// Writes an sfixed64 value, without a tag, to the stream. |
| 317 /// </summary> |
| 318 /// <param name="value">The value to write</param> |
| 319 public void WriteSFixed64(long value) |
| 320 { |
| 321 WriteRawLittleEndian64((ulong) value); |
| 322 } |
| 323 |
| 324 /// <summary> |
| 325 /// Writes an sint32 value, without a tag, to the stream. |
| 326 /// </summary> |
| 327 /// <param name="value">The value to write</param> |
| 328 public void WriteSInt32(int value) |
| 329 { |
| 330 WriteRawVarint32(EncodeZigZag32(value)); |
| 331 } |
| 332 |
| 333 /// <summary> |
| 334 /// Writes an sint64 value, without a tag, to the stream. |
| 335 /// </summary> |
| 336 /// <param name="value">The value to write</param> |
| 337 public void WriteSInt64(long value) |
| 338 { |
| 339 WriteRawVarint64(EncodeZigZag64(value)); |
| 340 } |
| 341 |
| 342 /// <summary> |
| 343 /// Writes a length (in bytes) for length-delimited data. |
| 344 /// </summary> |
| 345 /// <remarks> |
| 346 /// This method simply writes a rawint, but exists for clarity in callin
g code. |
| 347 /// </remarks> |
| 348 /// <param name="length">Length value, in bytes.</param> |
| 349 public void WriteLength(int length) |
| 350 { |
| 351 WriteRawVarint32((uint) length); |
| 352 } |
| 353 |
| 354 #endregion |
| 355 |
| 356 #region Raw tag writing |
| 357 /// <summary> |
| 358 /// Encodes and writes a tag. |
| 359 /// </summary> |
| 360 /// <param name="fieldNumber">The number of the field to write the tag f
or</param> |
| 361 /// <param name="type">The wire format type of the tag to write</param> |
| 362 public void WriteTag(int fieldNumber, WireFormat.WireType type) |
| 363 { |
| 364 WriteRawVarint32(WireFormat.MakeTag(fieldNumber, type)); |
| 365 } |
| 366 |
| 367 /// <summary> |
| 368 /// Writes an already-encoded tag. |
| 369 /// </summary> |
| 370 /// <param name="tag">The encoded tag</param> |
| 371 public void WriteTag(uint tag) |
| 372 { |
| 373 WriteRawVarint32(tag); |
| 374 } |
| 375 |
| 376 /// <summary> |
| 377 /// Writes the given single-byte tag directly to the stream. |
| 378 /// </summary> |
| 379 /// <param name="b1">The encoded tag</param> |
| 380 public void WriteRawTag(byte b1) |
| 381 { |
| 382 WriteRawByte(b1); |
| 383 } |
| 384 |
| 385 /// <summary> |
| 386 /// Writes the given two-byte tag directly to the stream. |
| 387 /// </summary> |
| 388 /// <param name="b1">The first byte of the encoded tag</param> |
| 389 /// <param name="b2">The second byte of the encoded tag</param> |
| 390 public void WriteRawTag(byte b1, byte b2) |
| 391 { |
| 392 WriteRawByte(b1); |
| 393 WriteRawByte(b2); |
| 394 } |
| 395 |
| 396 /// <summary> |
| 397 /// Writes the given three-byte tag directly to the stream. |
| 398 /// </summary> |
| 399 /// <param name="b1">The first byte of the encoded tag</param> |
| 400 /// <param name="b2">The second byte of the encoded tag</param> |
| 401 /// <param name="b3">The third byte of the encoded tag</param> |
| 402 public void WriteRawTag(byte b1, byte b2, byte b3) |
| 403 { |
| 404 WriteRawByte(b1); |
| 405 WriteRawByte(b2); |
| 406 WriteRawByte(b3); |
| 407 } |
| 408 |
| 409 /// <summary> |
| 410 /// Writes the given four-byte tag directly to the stream. |
| 411 /// </summary> |
| 412 /// <param name="b1">The first byte of the encoded tag</param> |
| 413 /// <param name="b2">The second byte of the encoded tag</param> |
| 414 /// <param name="b3">The third byte of the encoded tag</param> |
| 415 /// <param name="b4">The fourth byte of the encoded tag</param> |
| 416 public void WriteRawTag(byte b1, byte b2, byte b3, byte b4) |
| 417 { |
| 418 WriteRawByte(b1); |
| 419 WriteRawByte(b2); |
| 420 WriteRawByte(b3); |
| 421 WriteRawByte(b4); |
| 422 } |
| 423 |
| 424 /// <summary> |
| 425 /// Writes the given five-byte tag directly to the stream. |
| 426 /// </summary> |
| 427 /// <param name="b1">The first byte of the encoded tag</param> |
| 428 /// <param name="b2">The second byte of the encoded tag</param> |
| 429 /// <param name="b3">The third byte of the encoded tag</param> |
| 430 /// <param name="b4">The fourth byte of the encoded tag</param> |
| 431 /// <param name="b5">The fifth byte of the encoded tag</param> |
| 432 public void WriteRawTag(byte b1, byte b2, byte b3, byte b4, byte b5) |
| 433 { |
| 434 WriteRawByte(b1); |
| 435 WriteRawByte(b2); |
| 436 WriteRawByte(b3); |
| 437 WriteRawByte(b4); |
| 438 WriteRawByte(b5); |
| 439 } |
| 440 #endregion |
| 441 |
| 442 #region Underlying writing primitives |
| 443 /// <summary> |
| 444 /// Writes a 32 bit value as a varint. The fast route is taken when |
| 445 /// there's enough buffer space left to whizz through without checking |
| 446 /// for each byte; otherwise, we resort to calling WriteRawByte each tim
e. |
| 447 /// </summary> |
| 448 internal void WriteRawVarint32(uint value) |
| 449 { |
| 450 // Optimize for the common case of a single byte value |
| 451 if (value < 128 && position < limit) |
| 452 { |
| 453 buffer[position++] = (byte)value; |
| 454 return; |
| 455 } |
| 456 |
| 457 while (value > 127 && position < limit) |
| 458 { |
| 459 buffer[position++] = (byte) ((value & 0x7F) | 0x80); |
| 460 value >>= 7; |
| 461 } |
| 462 while (value > 127) |
| 463 { |
| 464 WriteRawByte((byte) ((value & 0x7F) | 0x80)); |
| 465 value >>= 7; |
| 466 } |
| 467 if (position < limit) |
| 468 { |
| 469 buffer[position++] = (byte) value; |
| 470 } |
| 471 else |
| 472 { |
| 473 WriteRawByte((byte) value); |
| 474 } |
| 475 } |
| 476 |
| 477 internal void WriteRawVarint64(ulong value) |
| 478 { |
| 479 while (value > 127 && position < limit) |
| 480 { |
| 481 buffer[position++] = (byte) ((value & 0x7F) | 0x80); |
| 482 value >>= 7; |
| 483 } |
| 484 while (value > 127) |
| 485 { |
| 486 WriteRawByte((byte) ((value & 0x7F) | 0x80)); |
| 487 value >>= 7; |
| 488 } |
| 489 if (position < limit) |
| 490 { |
| 491 buffer[position++] = (byte) value; |
| 492 } |
| 493 else |
| 494 { |
| 495 WriteRawByte((byte) value); |
| 496 } |
| 497 } |
| 498 |
| 499 internal void WriteRawLittleEndian32(uint value) |
| 500 { |
| 501 if (position + 4 > limit) |
| 502 { |
| 503 WriteRawByte((byte) value); |
| 504 WriteRawByte((byte) (value >> 8)); |
| 505 WriteRawByte((byte) (value >> 16)); |
| 506 WriteRawByte((byte) (value >> 24)); |
| 507 } |
| 508 else |
| 509 { |
| 510 buffer[position++] = ((byte) value); |
| 511 buffer[position++] = ((byte) (value >> 8)); |
| 512 buffer[position++] = ((byte) (value >> 16)); |
| 513 buffer[position++] = ((byte) (value >> 24)); |
| 514 } |
| 515 } |
| 516 |
| 517 internal void WriteRawLittleEndian64(ulong value) |
| 518 { |
| 519 if (position + 8 > limit) |
| 520 { |
| 521 WriteRawByte((byte) value); |
| 522 WriteRawByte((byte) (value >> 8)); |
| 523 WriteRawByte((byte) (value >> 16)); |
| 524 WriteRawByte((byte) (value >> 24)); |
| 525 WriteRawByte((byte) (value >> 32)); |
| 526 WriteRawByte((byte) (value >> 40)); |
| 527 WriteRawByte((byte) (value >> 48)); |
| 528 WriteRawByte((byte) (value >> 56)); |
| 529 } |
| 530 else |
| 531 { |
| 532 buffer[position++] = ((byte) value); |
| 533 buffer[position++] = ((byte) (value >> 8)); |
| 534 buffer[position++] = ((byte) (value >> 16)); |
| 535 buffer[position++] = ((byte) (value >> 24)); |
| 536 buffer[position++] = ((byte) (value >> 32)); |
| 537 buffer[position++] = ((byte) (value >> 40)); |
| 538 buffer[position++] = ((byte) (value >> 48)); |
| 539 buffer[position++] = ((byte) (value >> 56)); |
| 540 } |
| 541 } |
| 542 |
| 543 internal void WriteRawByte(byte value) |
| 544 { |
| 545 if (position == limit) |
| 546 { |
| 547 RefreshBuffer(); |
| 548 } |
| 549 |
| 550 buffer[position++] = value; |
| 551 } |
| 552 |
| 553 internal void WriteRawByte(uint value) |
| 554 { |
| 555 WriteRawByte((byte) value); |
| 556 } |
| 557 |
| 558 /// <summary> |
| 559 /// Writes out an array of bytes. |
| 560 /// </summary> |
| 561 internal void WriteRawBytes(byte[] value) |
| 562 { |
| 563 WriteRawBytes(value, 0, value.Length); |
| 564 } |
| 565 |
| 566 /// <summary> |
| 567 /// Writes out part of an array of bytes. |
| 568 /// </summary> |
| 569 internal void WriteRawBytes(byte[] value, int offset, int length) |
| 570 { |
| 571 if (limit - position >= length) |
| 572 { |
| 573 ByteArray.Copy(value, offset, buffer, position, length); |
| 574 // We have room in the current buffer. |
| 575 position += length; |
| 576 } |
| 577 else |
| 578 { |
| 579 // Write extends past current buffer. Fill the rest of this buf
fer and |
| 580 // flush. |
| 581 int bytesWritten = limit - position; |
| 582 ByteArray.Copy(value, offset, buffer, position, bytesWritten); |
| 583 offset += bytesWritten; |
| 584 length -= bytesWritten; |
| 585 position = limit; |
| 586 RefreshBuffer(); |
| 587 |
| 588 // Now deal with the rest. |
| 589 // Since we have an output stream, this is our buffer |
| 590 // and buffer offset == 0 |
| 591 if (length <= limit) |
| 592 { |
| 593 // Fits in new buffer. |
| 594 ByteArray.Copy(value, offset, buffer, 0, length); |
| 595 position = length; |
| 596 } |
| 597 else |
| 598 { |
| 599 // Write is very big. Let's do it all at once. |
| 600 output.Write(value, offset, length); |
| 601 } |
| 602 } |
| 603 } |
| 604 |
| 605 #endregion |
| 606 |
| 607 /// <summary> |
| 608 /// Encode a 32-bit value with ZigZag encoding. |
| 609 /// </summary> |
| 610 /// <remarks> |
| 611 /// ZigZag encodes signed integers into values that can be efficiently |
| 612 /// encoded with varint. (Otherwise, negative values must be |
| 613 /// sign-extended to 64 bits to be varint encoded, thus always taking |
| 614 /// 10 bytes on the wire.) |
| 615 /// </remarks> |
| 616 internal static uint EncodeZigZag32(int n) |
| 617 { |
| 618 // Note: the right-shift must be arithmetic |
| 619 return (uint) ((n << 1) ^ (n >> 31)); |
| 620 } |
| 621 |
| 622 /// <summary> |
| 623 /// Encode a 64-bit value with ZigZag encoding. |
| 624 /// </summary> |
| 625 /// <remarks> |
| 626 /// ZigZag encodes signed integers into values that can be efficiently |
| 627 /// encoded with varint. (Otherwise, negative values must be |
| 628 /// sign-extended to 64 bits to be varint encoded, thus always taking |
| 629 /// 10 bytes on the wire.) |
| 630 /// </remarks> |
| 631 internal static ulong EncodeZigZag64(long n) |
| 632 { |
| 633 return (ulong) ((n << 1) ^ (n >> 63)); |
| 634 } |
| 635 |
| 636 private void RefreshBuffer() |
| 637 { |
| 638 if (output == null) |
| 639 { |
| 640 // We're writing to a single buffer. |
| 641 throw new OutOfSpaceException(); |
| 642 } |
| 643 |
| 644 // Since we have an output stream, this is our buffer |
| 645 // and buffer offset == 0 |
| 646 output.Write(buffer, 0, position); |
| 647 position = 0; |
| 648 } |
| 649 |
| 650 /// <summary> |
| 651 /// Indicates that a CodedOutputStream wrapping a flat byte array |
| 652 /// ran out of space. |
| 653 /// </summary> |
| 654 public sealed class OutOfSpaceException : IOException |
| 655 { |
| 656 internal OutOfSpaceException() |
| 657 : base("CodedOutputStream was writing to a flat byte array and r
an out of space.") |
| 658 { |
| 659 } |
| 660 } |
| 661 |
| 662 /// <summary> |
| 663 /// Flushes any buffered data to the underlying stream (if there is one)
. |
| 664 /// </summary> |
| 665 public void Flush() |
| 666 { |
| 667 if (output != null) |
| 668 { |
| 669 RefreshBuffer(); |
| 670 } |
| 671 } |
| 672 |
| 673 /// <summary> |
| 674 /// Verifies that SpaceLeft returns zero. It's common to create a byte a
rray |
| 675 /// that is exactly big enough to hold a message, then write to it with |
| 676 /// a CodedOutputStream. Calling CheckNoSpaceLeft after writing verifies
that |
| 677 /// the message was actually as big as expected, which can help bugs. |
| 678 /// </summary> |
| 679 public void CheckNoSpaceLeft() |
| 680 { |
| 681 if (SpaceLeft != 0) |
| 682 { |
| 683 throw new InvalidOperationException("Did not write as much data
as expected."); |
| 684 } |
| 685 } |
| 686 |
| 687 /// <summary> |
| 688 /// If writing to a flat array, returns the space left in the array. Oth
erwise, |
| 689 /// throws an InvalidOperationException. |
| 690 /// </summary> |
| 691 public int SpaceLeft |
| 692 { |
| 693 get |
| 694 { |
| 695 if (output == null) |
| 696 { |
| 697 return limit - position; |
| 698 } |
| 699 else |
| 700 { |
| 701 throw new InvalidOperationException( |
| 702 "SpaceLeft can only be called on CodedOutputStreams that
are " + |
| 703 "writing to a flat array."); |
| 704 } |
| 705 } |
| 706 } |
| 707 } |
| 708 } |
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