1 /* 2 * Copyright 2014 Google Inc. All rights reserved. 3 * 4 * Licensed under the Apache License, Version 2.0 (the "License"); 5 * you may not use this file except in compliance with the License. 6 * You may obtain a copy of the License at 7 * 8 * http://www.apache.org/licenses/LICENSE-2.0 9 * 10 * Unless required by applicable law or agreed to in writing, software 11 * distributed under the License is distributed on an "AS IS" BASIS, 12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 13 * See the License for the specific language governing permissions and 14 * limitations under the License. 15 */ 16 17 18 using System; 19 using System.Collections.Generic; 20 using System.Text; 21 22 /// @file 23 /// @addtogroup flatbuffers_csharp_api 24 /// @{ 25 26 namespace FlatBuffers 27 { 28 /// <summary> 29 /// Responsible for building up and accessing a FlatBuffer formatted byte 30 /// array (via ByteBuffer). 31 /// </summary> 32 public class FlatBufferBuilder 33 { 34 private int _space; 35 private ByteBuffer _bb; 36 private int _minAlign = 1; 37 38 // The vtable for the current table (if _vtableSize >= 0) 39 private int[] _vtable = new int[16]; 40 // The size of the vtable. -1 indicates no vtable 41 private int _vtableSize = -1; 42 // Starting offset of the current struct/table. 43 private int _objectStart; 44 // List of offsets of all vtables. 45 private int[] _vtables = new int[16]; 46 // Number of entries in `vtables` in use. 47 private int _numVtables = 0; 48 // For the current vector being built. 49 private int _vectorNumElems = 0; 50 51 // For CreateSharedString 52 private Dictionary<string, StringOffset> _sharedStringMap = null; 53 54 /// <summary> 55 /// Create a FlatBufferBuilder with a given initial size. 56 /// </summary> 57 /// <param name="initialSize"> 58 /// The initial size to use for the internal buffer. 59 /// </param> FlatBufferBuilder(int initialSize)60 public FlatBufferBuilder(int initialSize) 61 { 62 if (initialSize <= 0) 63 throw new ArgumentOutOfRangeException("initialSize", 64 initialSize, "Must be greater than zero"); 65 _space = initialSize; 66 _bb = new ByteBuffer(initialSize); 67 } 68 69 /// <summary> 70 /// Create a FlatBufferBuilder backed by the pased in ByteBuffer 71 /// </summary> 72 /// <param name="buffer">The ByteBuffer to write to</param> FlatBufferBuilder(ByteBuffer buffer)73 public FlatBufferBuilder(ByteBuffer buffer) 74 { 75 _bb = buffer; 76 _space = buffer.Length; 77 buffer.Reset(); 78 } 79 80 /// <summary> 81 /// Reset the FlatBufferBuilder by purging all data that it holds. 82 /// </summary> Clear()83 public void Clear() 84 { 85 _space = _bb.Length; 86 _bb.Reset(); 87 _minAlign = 1; 88 while (_vtableSize > 0) _vtable[--_vtableSize] = 0; 89 _vtableSize = -1; 90 _objectStart = 0; 91 _numVtables = 0; 92 _vectorNumElems = 0; 93 } 94 95 /// <summary> 96 /// Gets and sets a Boolean to disable the optimization when serializing 97 /// default values to a Table. 98 /// 99 /// In order to save space, fields that are set to their default value 100 /// don't get serialized into the buffer. 101 /// </summary> 102 public bool ForceDefaults { get; set; } 103 104 /// @cond FLATBUFFERS_INTERNAL 105 106 public int Offset { get { return _bb.Length - _space; } } 107 Pad(int size)108 public void Pad(int size) 109 { 110 _bb.PutByte(_space -= size, 0, size); 111 } 112 113 // Doubles the size of the ByteBuffer, and copies the old data towards 114 // the end of the new buffer (since we build the buffer backwards). GrowBuffer()115 void GrowBuffer() 116 { 117 _bb.GrowFront(_bb.Length << 1); 118 } 119 120 // Prepare to write an element of `size` after `additional_bytes` 121 // have been written, e.g. if you write a string, you need to align 122 // such the int length field is aligned to SIZEOF_INT, and the string 123 // data follows it directly. 124 // If all you need to do is align, `additional_bytes` will be 0. Prep(int size, int additionalBytes)125 public void Prep(int size, int additionalBytes) 126 { 127 // Track the biggest thing we've ever aligned to. 128 if (size > _minAlign) 129 _minAlign = size; 130 // Find the amount of alignment needed such that `size` is properly 131 // aligned after `additional_bytes` 132 var alignSize = 133 ((~((int)_bb.Length - _space + additionalBytes)) + 1) & 134 (size - 1); 135 // Reallocate the buffer if needed. 136 while (_space < alignSize + size + additionalBytes) 137 { 138 var oldBufSize = (int)_bb.Length; 139 GrowBuffer(); 140 _space += (int)_bb.Length - oldBufSize; 141 142 } 143 if (alignSize > 0) 144 Pad(alignSize); 145 } 146 PutBool(bool x)147 public void PutBool(bool x) 148 { 149 _bb.PutByte(_space -= sizeof(byte), (byte)(x ? 1 : 0)); 150 } 151 PutSbyte(sbyte x)152 public void PutSbyte(sbyte x) 153 { 154 _bb.PutSbyte(_space -= sizeof(sbyte), x); 155 } 156 PutByte(byte x)157 public void PutByte(byte x) 158 { 159 _bb.PutByte(_space -= sizeof(byte), x); 160 } 161 PutShort(short x)162 public void PutShort(short x) 163 { 164 _bb.PutShort(_space -= sizeof(short), x); 165 } 166 PutUshort(ushort x)167 public void PutUshort(ushort x) 168 { 169 _bb.PutUshort(_space -= sizeof(ushort), x); 170 } 171 PutInt(int x)172 public void PutInt(int x) 173 { 174 _bb.PutInt(_space -= sizeof(int), x); 175 } 176 PutUint(uint x)177 public void PutUint(uint x) 178 { 179 _bb.PutUint(_space -= sizeof(uint), x); 180 } 181 PutLong(long x)182 public void PutLong(long x) 183 { 184 _bb.PutLong(_space -= sizeof(long), x); 185 } 186 PutUlong(ulong x)187 public void PutUlong(ulong x) 188 { 189 _bb.PutUlong(_space -= sizeof(ulong), x); 190 } 191 PutFloat(float x)192 public void PutFloat(float x) 193 { 194 _bb.PutFloat(_space -= sizeof(float), x); 195 } 196 197 /// <summary> 198 /// Puts an array of type T into this builder at the 199 /// current offset 200 /// </summary> 201 /// <typeparam name="T">The type of the input data </typeparam> 202 /// <param name="x">The array to copy data from</param> 203 public void Put<T>(T[] x) 204 where T : struct 205 { 206 _space = _bb.Put(_space, x); 207 } 208 209 #if ENABLE_SPAN_T 210 /// <summary> 211 /// Puts a span of type T into this builder at the 212 /// current offset 213 /// </summary> 214 /// <typeparam name="T">The type of the input data </typeparam> 215 /// <param name="x">The span to copy data from</param> 216 public void Put<T>(Span<T> x) 217 where T : struct 218 { 219 _space = _bb.Put(_space, x); 220 } 221 #endif 222 PutDouble(double x)223 public void PutDouble(double x) 224 { 225 _bb.PutDouble(_space -= sizeof(double), x); 226 } 227 /// @endcond 228 229 /// <summary> 230 /// Add a `bool` to the buffer (aligns the data and grows if necessary). 231 /// </summary> 232 /// <param name="x">The `bool` to add to the buffer.</param> AddBool(bool x)233 public void AddBool(bool x) { Prep(sizeof(byte), 0); PutBool(x); } 234 235 /// <summary> 236 /// Add a `sbyte` to the buffer (aligns the data and grows if necessary). 237 /// </summary> 238 /// <param name="x">The `sbyte` to add to the buffer.</param> AddSbyte(sbyte x)239 public void AddSbyte(sbyte x) { Prep(sizeof(sbyte), 0); PutSbyte(x); } 240 241 /// <summary> 242 /// Add a `byte` to the buffer (aligns the data and grows if necessary). 243 /// </summary> 244 /// <param name="x">The `byte` to add to the buffer.</param> AddByte(byte x)245 public void AddByte(byte x) { Prep(sizeof(byte), 0); PutByte(x); } 246 247 /// <summary> 248 /// Add a `short` to the buffer (aligns the data and grows if necessary). 249 /// </summary> 250 /// <param name="x">The `short` to add to the buffer.</param> AddShort(short x)251 public void AddShort(short x) { Prep(sizeof(short), 0); PutShort(x); } 252 253 /// <summary> 254 /// Add an `ushort` to the buffer (aligns the data and grows if necessary). 255 /// </summary> 256 /// <param name="x">The `ushort` to add to the buffer.</param> AddUshort(ushort x)257 public void AddUshort(ushort x) { Prep(sizeof(ushort), 0); PutUshort(x); } 258 259 /// <summary> 260 /// Add an `int` to the buffer (aligns the data and grows if necessary). 261 /// </summary> 262 /// <param name="x">The `int` to add to the buffer.</param> AddInt(int x)263 public void AddInt(int x) { Prep(sizeof(int), 0); PutInt(x); } 264 265 /// <summary> 266 /// Add an `uint` to the buffer (aligns the data and grows if necessary). 267 /// </summary> 268 /// <param name="x">The `uint` to add to the buffer.</param> AddUint(uint x)269 public void AddUint(uint x) { Prep(sizeof(uint), 0); PutUint(x); } 270 271 /// <summary> 272 /// Add a `long` to the buffer (aligns the data and grows if necessary). 273 /// </summary> 274 /// <param name="x">The `long` to add to the buffer.</param> AddLong(long x)275 public void AddLong(long x) { Prep(sizeof(long), 0); PutLong(x); } 276 277 /// <summary> 278 /// Add an `ulong` to the buffer (aligns the data and grows if necessary). 279 /// </summary> 280 /// <param name="x">The `ulong` to add to the buffer.</param> AddUlong(ulong x)281 public void AddUlong(ulong x) { Prep(sizeof(ulong), 0); PutUlong(x); } 282 283 /// <summary> 284 /// Add a `float` to the buffer (aligns the data and grows if necessary). 285 /// </summary> 286 /// <param name="x">The `float` to add to the buffer.</param> AddFloat(float x)287 public void AddFloat(float x) { Prep(sizeof(float), 0); PutFloat(x); } 288 289 /// <summary> 290 /// Add an array of type T to the buffer (aligns the data and grows if necessary). 291 /// </summary> 292 /// <typeparam name="T">The type of the input data</typeparam> 293 /// <param name="x">The array to copy data from</param> 294 public void Add<T>(T[] x) 295 where T : struct 296 { 297 if (x == null) 298 { 299 throw new ArgumentNullException("Cannot add a null array"); 300 } 301 302 if( x.Length == 0) 303 { 304 // don't do anything if the array is empty 305 return; 306 } 307 308 if(!ByteBuffer.IsSupportedType<T>()) 309 { 310 throw new ArgumentException("Cannot add this Type array to the builder"); 311 } 312 313 int size = ByteBuffer.SizeOf<T>(); 314 // Need to prep on size (for data alignment) and then we pass the 315 // rest of the length (minus 1) as additional bytes PrepFlatBuffers.FlatBufferBuilder.__anon3316 Prep(size, size * (x.Length - 1)); PutFlatBuffers.FlatBufferBuilder.__anon3317 Put(x); 318 } 319 320 #if ENABLE_SPAN_T 321 /// <summary> 322 /// Add a span of type T to the buffer (aligns the data and grows if necessary). 323 /// </summary> 324 /// <typeparam name="T">The type of the input data</typeparam> 325 /// <param name="x">The span to copy data from</param> 326 public void Add<T>(Span<T> x) 327 where T : struct 328 { 329 if (!ByteBuffer.IsSupportedType<T>()) 330 { 331 throw new ArgumentException("Cannot add this Type array to the builder"); 332 } 333 334 int size = ByteBuffer.SizeOf<T>(); 335 // Need to prep on size (for data alignment) and then we pass the 336 // rest of the length (minus 1) as additional bytes PrepFlatBuffers.FlatBufferBuilder.__anon4337 Prep(size, size * (x.Length - 1)); PutFlatBuffers.FlatBufferBuilder.__anon4338 Put(x); 339 } 340 #endif 341 342 /// <summary> 343 /// Add a `double` to the buffer (aligns the data and grows if necessary). 344 /// </summary> 345 /// <param name="x">The `double` to add to the buffer.</param> AddDouble(double x)346 public void AddDouble(double x) { Prep(sizeof(double), 0); 347 PutDouble(x); } 348 349 /// <summary> 350 /// Adds an offset, relative to where it will be written. 351 /// </summary> 352 /// <param name="off">The offset to add to the buffer.</param> AddOffset(int off)353 public void AddOffset(int off) 354 { 355 Prep(sizeof(int), 0); // Ensure alignment is already done. 356 if (off > Offset) 357 throw new ArgumentException(); 358 359 off = Offset - off + sizeof(int); 360 PutInt(off); 361 } 362 363 /// @cond FLATBUFFERS_INTERNAL StartVector(int elemSize, int count, int alignment)364 public void StartVector(int elemSize, int count, int alignment) 365 { 366 NotNested(); 367 _vectorNumElems = count; 368 Prep(sizeof(int), elemSize * count); 369 Prep(alignment, elemSize * count); // Just in case alignment > int. 370 } 371 /// @endcond 372 373 /// <summary> 374 /// Writes data necessary to finish a vector construction. 375 /// </summary> EndVector()376 public VectorOffset EndVector() 377 { 378 PutInt(_vectorNumElems); 379 return new VectorOffset(Offset); 380 } 381 382 /// <summary> 383 /// Creates a vector of tables. 384 /// </summary> 385 /// <param name="offsets">Offsets of the tables.</param> 386 public VectorOffset CreateVectorOfTables<T>(Offset<T>[] offsets) where T : struct 387 { NotNestedFlatBuffers.FlatBufferBuilder.__anon5388 NotNested(); sizeofFlatBuffers.FlatBufferBuilder.__anon5389 StartVector(sizeof(int), offsets.Length, sizeof(int)); AddOffsetFlatBuffers.FlatBufferBuilder.__anon5390 for (int i = offsets.Length - 1; i >= 0; i--) AddOffset(offsets[i].Value); 391 return EndVector(); 392 } 393 394 /// @cond FLATBUFFERS_INTENRAL Nested(int obj)395 public void Nested(int obj) 396 { 397 // Structs are always stored inline, so need to be created right 398 // where they are used. You'll get this assert if you created it 399 // elsewhere. 400 if (obj != Offset) 401 throw new Exception( 402 "FlatBuffers: struct must be serialized inline."); 403 } 404 NotNested()405 public void NotNested() 406 { 407 // You should not be creating any other objects or strings/vectors 408 // while an object is being constructed 409 if (_vtableSize >= 0) 410 throw new Exception( 411 "FlatBuffers: object serialization must not be nested."); 412 } 413 StartTable(int numfields)414 public void StartTable(int numfields) 415 { 416 if (numfields < 0) 417 throw new ArgumentOutOfRangeException("Flatbuffers: invalid numfields"); 418 419 NotNested(); 420 421 if (_vtable.Length < numfields) 422 _vtable = new int[numfields]; 423 424 _vtableSize = numfields; 425 _objectStart = Offset; 426 } 427 428 429 // Set the current vtable at `voffset` to the current location in the 430 // buffer. Slot(int voffset)431 public void Slot(int voffset) 432 { 433 if (voffset >= _vtableSize) 434 throw new IndexOutOfRangeException("Flatbuffers: invalid voffset"); 435 436 _vtable[voffset] = Offset; 437 } 438 439 /// <summary> 440 /// Adds a Boolean to the Table at index `o` in its vtable using the value `x` and default `d` 441 /// </summary> 442 /// <param name="o">The index into the vtable</param> 443 /// <param name="x">The value to put into the buffer. If the value is equal to the default 444 /// and <see cref="ForceDefaults"/> is false, the value will be skipped.</param> 445 /// <param name="d">The default value to compare the value against</param> AddBool(int o, bool x, bool d)446 public void AddBool(int o, bool x, bool d) { if (ForceDefaults || x != d) { AddBool(x); Slot(o); } } 447 448 /// <summary> 449 /// Adds a SByte to the Table at index `o` in its vtable using the value `x` and default `d` 450 /// </summary> 451 /// <param name="o">The index into the vtable</param> 452 /// <param name="x">The value to put into the buffer. If the value is equal to the default 453 /// and <see cref="ForceDefaults"/> is false, the value will be skipped.</param> 454 /// <param name="d">The default value to compare the value against</param> AddSbyte(int o, sbyte x, sbyte d)455 public void AddSbyte(int o, sbyte x, sbyte d) { if (ForceDefaults || x != d) { AddSbyte(x); Slot(o); } } 456 457 /// <summary> 458 /// Adds a Byte to the Table at index `o` in its vtable using the value `x` and default `d` 459 /// </summary> 460 /// <param name="o">The index into the vtable</param> 461 /// <param name="x">The value to put into the buffer. If the value is equal to the default 462 /// and <see cref="ForceDefaults"/> is false, the value will be skipped.</param> 463 /// <param name="d">The default value to compare the value against</param> AddByte(int o, byte x, byte d)464 public void AddByte(int o, byte x, byte d) { if (ForceDefaults || x != d) { AddByte(x); Slot(o); } } 465 466 /// <summary> 467 /// Adds a Int16 to the Table at index `o` in its vtable using the value `x` and default `d` 468 /// </summary> 469 /// <param name="o">The index into the vtable</param> 470 /// <param name="x">The value to put into the buffer. If the value is equal to the default 471 /// and <see cref="ForceDefaults"/> is false, the value will be skipped.</param> 472 /// <param name="d">The default value to compare the value against</param> AddShort(int o, short x, int d)473 public void AddShort(int o, short x, int d) { if (ForceDefaults || x != d) { AddShort(x); Slot(o); } } 474 475 /// <summary> 476 /// Adds a UInt16 to the Table at index `o` in its vtable using the value `x` and default `d` 477 /// </summary> 478 /// <param name="o">The index into the vtable</param> 479 /// <param name="x">The value to put into the buffer. If the value is equal to the default 480 /// and <see cref="ForceDefaults"/> is false, the value will be skipped.</param> 481 /// <param name="d">The default value to compare the value against</param> AddUshort(int o, ushort x, ushort d)482 public void AddUshort(int o, ushort x, ushort d) { if (ForceDefaults || x != d) { AddUshort(x); Slot(o); } } 483 484 /// <summary> 485 /// Adds an Int32 to the Table at index `o` in its vtable using the value `x` and default `d` 486 /// </summary> 487 /// <param name="o">The index into the vtable</param> 488 /// <param name="x">The value to put into the buffer. If the value is equal to the default 489 /// and <see cref="ForceDefaults"/> is false, the value will be skipped.</param> 490 /// <param name="d">The default value to compare the value against</param> AddInt(int o, int x, int d)491 public void AddInt(int o, int x, int d) { if (ForceDefaults || x != d) { AddInt(x); Slot(o); } } 492 493 /// <summary> 494 /// Adds a UInt32 to the Table at index `o` in its vtable using the value `x` and default `d` 495 /// </summary> 496 /// <param name="o">The index into the vtable</param> 497 /// <param name="x">The value to put into the buffer. If the value is equal to the default 498 /// and <see cref="ForceDefaults"/> is false, the value will be skipped.</param> 499 /// <param name="d">The default value to compare the value against</param> AddUint(int o, uint x, uint d)500 public void AddUint(int o, uint x, uint d) { if (ForceDefaults || x != d) { AddUint(x); Slot(o); } } 501 502 /// <summary> 503 /// Adds an Int64 to the Table at index `o` in its vtable using the value `x` and default `d` 504 /// </summary> 505 /// <param name="o">The index into the vtable</param> 506 /// <param name="x">The value to put into the buffer. If the value is equal to the default 507 /// and <see cref="ForceDefaults"/> is false, the value will be skipped.</param> 508 /// <param name="d">The default value to compare the value against</param> AddLong(int o, long x, long d)509 public void AddLong(int o, long x, long d) { if (ForceDefaults || x != d) { AddLong(x); Slot(o); } } 510 511 /// <summary> 512 /// Adds a UInt64 to the Table at index `o` in its vtable using the value `x` and default `d` 513 /// </summary> 514 /// <param name="o">The index into the vtable</param> 515 /// <param name="x">The value to put into the buffer. If the value is equal to the default 516 /// and <see cref="ForceDefaults"/> is false, the value will be skipped.</param> 517 /// <param name="d">The default value to compare the value against</param> AddUlong(int o, ulong x, ulong d)518 public void AddUlong(int o, ulong x, ulong d) { if (ForceDefaults || x != d) { AddUlong(x); Slot(o); } } 519 520 /// <summary> 521 /// Adds a Single to the Table at index `o` in its vtable using the value `x` and default `d` 522 /// </summary> 523 /// <param name="o">The index into the vtable</param> 524 /// <param name="x">The value to put into the buffer. If the value is equal to the default 525 /// and <see cref="ForceDefaults"/> is false, the value will be skipped.</param> 526 /// <param name="d">The default value to compare the value against</param> AddFloat(int o, float x, double d)527 public void AddFloat(int o, float x, double d) { if (ForceDefaults || x != d) { AddFloat(x); Slot(o); } } 528 529 /// <summary> 530 /// Adds a Double to the Table at index `o` in its vtable using the value `x` and default `d` 531 /// </summary> 532 /// <param name="o">The index into the vtable</param> 533 /// <param name="x">The value to put into the buffer. If the value is equal to the default 534 /// and <see cref="ForceDefaults"/> is false, the value will be skipped.</param> 535 /// <param name="d">The default value to compare the value against</param> AddDouble(int o, double x, double d)536 public void AddDouble(int o, double x, double d) { if (ForceDefaults || x != d) { AddDouble(x); Slot(o); } } 537 538 /// <summary> 539 /// Adds a buffer offset to the Table at index `o` in its vtable using the value `x` and default `d` 540 /// </summary> 541 /// <param name="o">The index into the vtable</param> 542 /// <param name="x">The value to put into the buffer. If the value is equal to the default 543 /// the value will be skipped.</param> 544 /// <param name="d">The default value to compare the value against</param> AddOffset(int o, int x, int d)545 public void AddOffset(int o, int x, int d) { if (x != d) { AddOffset(x); Slot(o); } } 546 /// @endcond 547 548 /// <summary> 549 /// Encode the string `s` in the buffer using UTF-8. 550 /// </summary> 551 /// <param name="s">The string to encode.</param> 552 /// <returns> 553 /// The offset in the buffer where the encoded string starts. 554 /// </returns> CreateString(string s)555 public StringOffset CreateString(string s) 556 { 557 NotNested(); 558 AddByte(0); 559 var utf8StringLen = Encoding.UTF8.GetByteCount(s); 560 StartVector(1, utf8StringLen, 1); 561 _bb.PutStringUTF8(_space -= utf8StringLen, s); 562 return new StringOffset(EndVector().Value); 563 } 564 565 566 #if ENABLE_SPAN_T 567 /// <summary> 568 /// Creates a string in the buffer from a Span containing 569 /// a UTF8 string. 570 /// </summary> 571 /// <param name="chars">the UTF8 string to add to the buffer</param> 572 /// <returns> 573 /// The offset in the buffer where the encoded string starts. 574 /// </returns> CreateUTF8String(Span<byte> chars)575 public StringOffset CreateUTF8String(Span<byte> chars) 576 { 577 NotNested(); 578 AddByte(0); 579 var utf8StringLen = chars.Length; 580 StartVector(1, utf8StringLen, 1); 581 _space = _bb.Put(_space, chars); 582 return new StringOffset(EndVector().Value); 583 } 584 #endif 585 586 /// <summary> 587 /// Store a string in the buffer, which can contain any binary data. 588 /// If a string with this exact contents has already been serialized before, 589 /// instead simply returns the offset of the existing string. 590 /// </summary> 591 /// <param name="s">The string to encode.</param> 592 /// <returns> 593 /// The offset in the buffer where the encoded string starts. 594 /// </returns> CreateSharedString(string s)595 public StringOffset CreateSharedString(string s) 596 { 597 if (_sharedStringMap == null) 598 { 599 _sharedStringMap = new Dictionary<string, StringOffset>(); 600 } 601 602 if (_sharedStringMap.ContainsKey(s)) 603 { 604 return _sharedStringMap[s]; 605 } 606 607 var stringOffset = CreateString(s); 608 _sharedStringMap.Add(s, stringOffset); 609 return stringOffset; 610 } 611 612 /// @cond FLATBUFFERS_INTERNAL 613 // Structs are stored inline, so nothing additional is being added. 614 // `d` is always 0. AddStruct(int voffset, int x, int d)615 public void AddStruct(int voffset, int x, int d) 616 { 617 if (x != d) 618 { 619 Nested(x); 620 Slot(voffset); 621 } 622 } 623 EndTable()624 public int EndTable() 625 { 626 if (_vtableSize < 0) 627 throw new InvalidOperationException( 628 "Flatbuffers: calling EndTable without a StartTable"); 629 630 AddInt((int)0); 631 var vtableloc = Offset; 632 // Write out the current vtable. 633 int i = _vtableSize - 1; 634 // Trim trailing zeroes. 635 for (; i >= 0 && _vtable[i] == 0; i--) {} 636 int trimmedSize = i + 1; 637 for (; i >= 0 ; i--) { 638 // Offset relative to the start of the table. 639 short off = (short)(_vtable[i] != 0 640 ? vtableloc - _vtable[i] 641 : 0); 642 AddShort(off); 643 644 // clear out written entry 645 _vtable[i] = 0; 646 } 647 648 const int standardFields = 2; // The fields below: 649 AddShort((short)(vtableloc - _objectStart)); 650 AddShort((short)((trimmedSize + standardFields) * 651 sizeof(short))); 652 653 // Search for an existing vtable that matches the current one. 654 int existingVtable = 0; 655 for (i = 0; i < _numVtables; i++) { 656 int vt1 = _bb.Length - _vtables[i]; 657 int vt2 = _space; 658 short len = _bb.GetShort(vt1); 659 if (len == _bb.GetShort(vt2)) { 660 for (int j = sizeof(short); j < len; j += sizeof(short)) { 661 if (_bb.GetShort(vt1 + j) != _bb.GetShort(vt2 + j)) { 662 goto endLoop; 663 } 664 } 665 existingVtable = _vtables[i]; 666 break; 667 } 668 669 endLoop: { } 670 } 671 672 if (existingVtable != 0) { 673 // Found a match: 674 // Remove the current vtable. 675 _space = _bb.Length - vtableloc; 676 // Point table to existing vtable. 677 _bb.PutInt(_space, existingVtable - vtableloc); 678 } else { 679 // No match: 680 // Add the location of the current vtable to the list of 681 // vtables. 682 if (_numVtables == _vtables.Length) 683 { 684 // Arrays.CopyOf(vtables num_vtables * 2); 685 var newvtables = new int[ _numVtables * 2]; 686 Array.Copy(_vtables, newvtables, _vtables.Length); 687 688 _vtables = newvtables; 689 }; 690 _vtables[_numVtables++] = Offset; 691 // Point table to current vtable. 692 _bb.PutInt(_bb.Length - vtableloc, Offset - vtableloc); 693 } 694 695 _vtableSize = -1; 696 return vtableloc; 697 } 698 699 // This checks a required field has been set in a given table that has 700 // just been constructed. Required(int table, int field)701 public void Required(int table, int field) 702 { 703 int table_start = _bb.Length - table; 704 int vtable_start = table_start - _bb.GetInt(table_start); 705 bool ok = _bb.GetShort(vtable_start + field) != 0; 706 // If this fails, the caller will show what field needs to be set. 707 if (!ok) 708 throw new InvalidOperationException("FlatBuffers: field " + field + 709 " must be set"); 710 } 711 /// @endcond 712 713 /// <summary> 714 /// Finalize a buffer, pointing to the given `root_table`. 715 /// </summary> 716 /// <param name="rootTable"> 717 /// An offset to be added to the buffer. 718 /// </param> 719 /// <param name="sizePrefix"> 720 /// Whether to prefix the size to the buffer. 721 /// </param> Finish(int rootTable, bool sizePrefix)722 protected void Finish(int rootTable, bool sizePrefix) 723 { 724 Prep(_minAlign, sizeof(int) + (sizePrefix ? sizeof(int) : 0)); 725 AddOffset(rootTable); 726 if (sizePrefix) { 727 AddInt(_bb.Length - _space); 728 } 729 _bb.Position = _space; 730 } 731 732 /// <summary> 733 /// Finalize a buffer, pointing to the given `root_table`. 734 /// </summary> 735 /// <param name="rootTable"> 736 /// An offset to be added to the buffer. 737 /// </param> Finish(int rootTable)738 public void Finish(int rootTable) 739 { 740 Finish(rootTable, false); 741 } 742 743 /// <summary> 744 /// Finalize a buffer, pointing to the given `root_table`, with the size prefixed. 745 /// </summary> 746 /// <param name="rootTable"> 747 /// An offset to be added to the buffer. 748 /// </param> FinishSizePrefixed(int rootTable)749 public void FinishSizePrefixed(int rootTable) 750 { 751 Finish(rootTable, true); 752 } 753 754 /// <summary> 755 /// Get the ByteBuffer representing the FlatBuffer. 756 /// </summary> 757 /// <remarks> 758 /// This is typically only called after you call `Finish()`. 759 /// The actual data starts at the ByteBuffer's current position, 760 /// not necessarily at `0`. 761 /// </remarks> 762 /// <returns> 763 /// Returns the ByteBuffer for this FlatBuffer. 764 /// </returns> 765 public ByteBuffer DataBuffer { get { return _bb; } } 766 767 /// <summary> 768 /// A utility function to copy and return the ByteBuffer data as a 769 /// `byte[]`. 770 /// </summary> 771 /// <returns> 772 /// A full copy of the FlatBuffer data. 773 /// </returns> SizedByteArray()774 public byte[] SizedByteArray() 775 { 776 return _bb.ToSizedArray(); 777 } 778 779 /// <summary> 780 /// Finalize a buffer, pointing to the given `rootTable`. 781 /// </summary> 782 /// <param name="rootTable"> 783 /// An offset to be added to the buffer. 784 /// </param> 785 /// <param name="fileIdentifier"> 786 /// A FlatBuffer file identifier to be added to the buffer before 787 /// `root_table`. 788 /// </param> 789 /// <param name="sizePrefix"> 790 /// Whether to prefix the size to the buffer. 791 /// </param> Finish(int rootTable, string fileIdentifier, bool sizePrefix)792 protected void Finish(int rootTable, string fileIdentifier, bool sizePrefix) 793 { 794 Prep(_minAlign, sizeof(int) + (sizePrefix ? sizeof(int) : 0) + 795 FlatBufferConstants.FileIdentifierLength); 796 if (fileIdentifier.Length != 797 FlatBufferConstants.FileIdentifierLength) 798 throw new ArgumentException( 799 "FlatBuffers: file identifier must be length " + 800 FlatBufferConstants.FileIdentifierLength, 801 "fileIdentifier"); 802 for (int i = FlatBufferConstants.FileIdentifierLength - 1; i >= 0; 803 i--) 804 { 805 AddByte((byte)fileIdentifier[i]); 806 } 807 Finish(rootTable, sizePrefix); 808 } 809 810 /// <summary> 811 /// Finalize a buffer, pointing to the given `rootTable`. 812 /// </summary> 813 /// <param name="rootTable"> 814 /// An offset to be added to the buffer. 815 /// </param> 816 /// <param name="fileIdentifier"> 817 /// A FlatBuffer file identifier to be added to the buffer before 818 /// `root_table`. 819 /// </param> Finish(int rootTable, string fileIdentifier)820 public void Finish(int rootTable, string fileIdentifier) 821 { 822 Finish(rootTable, fileIdentifier, false); 823 } 824 825 /// <summary> 826 /// Finalize a buffer, pointing to the given `rootTable`, with the size prefixed. 827 /// </summary> 828 /// <param name="rootTable"> 829 /// An offset to be added to the buffer. 830 /// </param> 831 /// <param name="fileIdentifier"> 832 /// A FlatBuffer file identifier to be added to the buffer before 833 /// `root_table`. 834 /// </param> FinishSizePrefixed(int rootTable, string fileIdentifier)835 public void FinishSizePrefixed(int rootTable, string fileIdentifier) 836 { 837 Finish(rootTable, fileIdentifier, true); 838 } 839 } 840 } 841 842 /// @} 843