| | | 1 | | // Licensed to the .NET Foundation under one or more agreements. |
| | | 2 | | // The .NET Foundation licenses this file to you under the MIT license. |
| | | 3 | | |
| | | 4 | | using System.Buffers; |
| | | 5 | | using System.Diagnostics; |
| | | 6 | | |
| | | 7 | | namespace System.Net |
| | | 8 | | { |
| | | 9 | | // Warning: Mutable struct! |
| | | 10 | | // The purpose of this struct is to simplify buffer management in cases where the size of the buffer may grow large |
| | | 11 | | // thus making it worthwhile to add the overhead involved in managing multiple individual array allocations. |
| | | 12 | | // Like ArrayBuffer, this manages a sliding buffer where bytes can be added at the end and removed at the beginning. |
| | | 13 | | // Unlike ArrayBuffer, the buffer itself is managed using 16K blocks which are added/removed to the block list as ne |
| | | 14 | | |
| | | 15 | | // 'ActiveBuffer' contains the current buffer contents; these bytes will be preserved on any call to TryEnsureAvaila |
| | | 16 | | // 'AvailableBuffer' contains the available bytes past the end of the current content, |
| | | 17 | | // and can be written to in order to add data to the end of the buffer. |
| | | 18 | | // Commit(byteCount) will extend the ActiveBuffer by 'byteCount' bytes into the AvailableBuffer. |
| | | 19 | | // Discard(byteCount) will discard 'byteCount' bytes as the beginning of the ActiveBuffer. |
| | | 20 | | // TryEnsureAvailableBytesUpToLimit will grow the buffer if necessary; *however*, this may invalidate |
| | | 21 | | // old values of 'ActiveBuffer' and 'AvailableBuffer', so they must be retrieved again. |
| | | 22 | | |
| | | 23 | | internal struct MultiArrayBuffer : IDisposable |
| | | 24 | | { |
| | | 25 | | private byte[]?[]? _blocks; |
| | | 26 | | private uint _allocatedEnd; |
| | | 27 | | private uint _activeStart; |
| | | 28 | | private uint _availableStart; |
| | | 29 | | |
| | | 30 | | // Invariants: |
| | | 31 | | // 0 <= _activeStart <= _availableStart <= total buffer size (i.e. _blockCount * BlockSize) |
| | | 32 | | |
| | | 33 | | private const int BlockSize = 16 * 1024; |
| | | 34 | | |
| | 0 | 35 | | public MultiArrayBuffer(int initialBufferSize) : this() |
| | 0 | 36 | | { |
| | | 37 | | // 'initialBufferSize' is ignored for now. Some callers are passing useful info here that we might want to a |
| | 0 | 38 | | Debug.Assert(initialBufferSize >= 0); |
| | 0 | 39 | | } |
| | | 40 | | |
| | | 41 | | public void Dispose() |
| | 0 | 42 | | { |
| | 0 | 43 | | _activeStart = 0; |
| | 0 | 44 | | _availableStart = 0; |
| | | 45 | | |
| | 0 | 46 | | if (_blocks is not null) |
| | 0 | 47 | | { |
| | 0 | 48 | | for (int i = 0; i < _blocks.Length; i++) |
| | 0 | 49 | | { |
| | 0 | 50 | | if (_blocks[i] is byte[] toReturn) |
| | 0 | 51 | | { |
| | 0 | 52 | | _blocks[i] = null; |
| | 0 | 53 | | ArrayPool<byte>.Shared.Return(toReturn); |
| | 0 | 54 | | } |
| | 0 | 55 | | } |
| | | 56 | | |
| | 0 | 57 | | _blocks = null; |
| | 0 | 58 | | _allocatedEnd = 0; |
| | 0 | 59 | | } |
| | 0 | 60 | | } |
| | | 61 | | |
| | 0 | 62 | | public bool IsEmpty => _activeStart == _availableStart; |
| | | 63 | | |
| | 0 | 64 | | public MultiMemory ActiveMemory => new MultiMemory(_blocks, _activeStart, _availableStart - _activeStart); |
| | | 65 | | |
| | 0 | 66 | | public MultiMemory AvailableMemory => new MultiMemory(_blocks, _availableStart, _allocatedEnd - _availableStart) |
| | | 67 | | |
| | | 68 | | public void Discard(int byteCount) |
| | 0 | 69 | | { |
| | 0 | 70 | | Debug.Assert(byteCount >= 0); |
| | 0 | 71 | | Debug.Assert(byteCount <= ActiveMemory.Length, $"MultiArrayBuffer.Discard: Expected byteCount={byteCount} <= |
| | | 72 | | |
| | 0 | 73 | | if (byteCount == ActiveMemory.Length) |
| | 0 | 74 | | { |
| | 0 | 75 | | DiscardAll(); |
| | 0 | 76 | | return; |
| | | 77 | | } |
| | | 78 | | |
| | 0 | 79 | | CheckState(); |
| | | 80 | | |
| | 0 | 81 | | uint ubyteCount = (uint)byteCount; |
| | | 82 | | |
| | 0 | 83 | | uint oldStartBlock = _activeStart / BlockSize; |
| | 0 | 84 | | _activeStart += ubyteCount; |
| | 0 | 85 | | uint newStartBlock = _activeStart / BlockSize; |
| | | 86 | | |
| | 0 | 87 | | FreeBlocks(oldStartBlock, newStartBlock); |
| | | 88 | | |
| | 0 | 89 | | CheckState(); |
| | 0 | 90 | | } |
| | | 91 | | |
| | | 92 | | public void DiscardAll() |
| | 0 | 93 | | { |
| | 0 | 94 | | CheckState(); |
| | | 95 | | |
| | 0 | 96 | | uint firstAllocatedBlock = _activeStart / BlockSize; |
| | 0 | 97 | | uint firstUnallocatedBlock = _allocatedEnd / BlockSize; |
| | 0 | 98 | | FreeBlocks(firstAllocatedBlock, firstUnallocatedBlock); |
| | | 99 | | |
| | 0 | 100 | | _activeStart = _availableStart = _allocatedEnd = 0; |
| | | 101 | | |
| | 0 | 102 | | CheckState(); |
| | | 103 | | |
| | 0 | 104 | | } |
| | | 105 | | |
| | | 106 | | private void FreeBlocks(uint startBlock, uint endBlock) |
| | 0 | 107 | | { |
| | 0 | 108 | | byte[]?[] blocks = _blocks!; |
| | 0 | 109 | | for (uint i = startBlock; i < endBlock; i++) |
| | 0 | 110 | | { |
| | 0 | 111 | | byte[]? toReturn = blocks[i]; |
| | 0 | 112 | | Debug.Assert(toReturn is not null); |
| | 0 | 113 | | blocks[i] = null; |
| | 0 | 114 | | ArrayPool<byte>.Shared.Return(toReturn); |
| | 0 | 115 | | } |
| | 0 | 116 | | } |
| | | 117 | | |
| | | 118 | | public void Commit(int byteCount) |
| | 0 | 119 | | { |
| | 0 | 120 | | Debug.Assert(byteCount >= 0); |
| | 0 | 121 | | Debug.Assert(byteCount <= AvailableMemory.Length, $"MultiArrayBuffer.Commit: Expected byteCount={byteCount} |
| | | 122 | | |
| | 0 | 123 | | uint ubyteCount = (uint)byteCount; |
| | | 124 | | |
| | 0 | 125 | | _availableStart += ubyteCount; |
| | 0 | 126 | | } |
| | | 127 | | |
| | | 128 | | public void EnsureAvailableSpaceUpToLimit(int byteCount, int limit) |
| | | 129 | | { |
| | | 130 | | Debug.Assert(byteCount >= 0); |
| | | 131 | | Debug.Assert(limit >= 0); |
| | | 132 | | |
| | | 133 | | if (ActiveMemory.Length >= limit) |
| | | 134 | | { |
| | | 135 | | // Already past limit. Do nothing. |
| | | 136 | | return; |
| | | 137 | | } |
| | | 138 | | |
| | | 139 | | // Enforce the limit. |
| | | 140 | | byteCount = Math.Min(byteCount, limit - ActiveMemory.Length); |
| | | 141 | | |
| | | 142 | | EnsureAvailableSpace(byteCount); |
| | | 143 | | } |
| | | 144 | | |
| | | 145 | | public void EnsureAvailableSpace(int byteCount) |
| | 0 | 146 | | { |
| | 0 | 147 | | Debug.Assert(byteCount >= 0); |
| | | 148 | | |
| | 0 | 149 | | if (byteCount > AvailableMemory.Length) |
| | 0 | 150 | | { |
| | 0 | 151 | | GrowAvailableSpace(byteCount); |
| | 0 | 152 | | } |
| | 0 | 153 | | } |
| | | 154 | | |
| | | 155 | | public void GrowAvailableSpace(int byteCount) |
| | 0 | 156 | | { |
| | 0 | 157 | | Debug.Assert(byteCount > AvailableMemory.Length); |
| | | 158 | | |
| | 0 | 159 | | CheckState(); |
| | | 160 | | |
| | 0 | 161 | | uint ubyteCount = (uint)byteCount; |
| | | 162 | | |
| | 0 | 163 | | uint newBytesNeeded = ubyteCount - (uint)AvailableMemory.Length; |
| | 0 | 164 | | uint newBlocksNeeded = (newBytesNeeded + BlockSize - 1) / BlockSize; |
| | | 165 | | |
| | | 166 | | // Ensure we have enough space in the block array for the new blocks needed. |
| | 0 | 167 | | if (_blocks is null) |
| | 0 | 168 | | { |
| | 0 | 169 | | Debug.Assert(_allocatedEnd == 0); |
| | 0 | 170 | | Debug.Assert(_activeStart == 0); |
| | 0 | 171 | | Debug.Assert(_availableStart == 0); |
| | | 172 | | |
| | 0 | 173 | | int blockArraySize = 4; |
| | 0 | 174 | | while (blockArraySize < newBlocksNeeded) |
| | 0 | 175 | | { |
| | 0 | 176 | | blockArraySize *= 2; |
| | 0 | 177 | | } |
| | | 178 | | |
| | 0 | 179 | | _blocks = new byte[]?[blockArraySize]; |
| | 0 | 180 | | } |
| | | 181 | | else |
| | 0 | 182 | | { |
| | 0 | 183 | | Debug.Assert(_allocatedEnd % BlockSize == 0); |
| | 0 | 184 | | Debug.Assert(_allocatedEnd <= _blocks.Length * BlockSize); |
| | | 185 | | |
| | 0 | 186 | | uint allocatedBlocks = _allocatedEnd / BlockSize; |
| | 0 | 187 | | uint blockArraySize = (uint)_blocks.Length; |
| | 0 | 188 | | if (allocatedBlocks + newBlocksNeeded > blockArraySize) |
| | 0 | 189 | | { |
| | | 190 | | // Not enough room in current block array. |
| | 0 | 191 | | uint unusedInitialBlocks = _activeStart / BlockSize; |
| | 0 | 192 | | uint usedBlocks = (allocatedBlocks - unusedInitialBlocks); |
| | 0 | 193 | | uint blocksNeeded = usedBlocks + newBlocksNeeded; |
| | 0 | 194 | | if (blocksNeeded > blockArraySize) |
| | 0 | 195 | | { |
| | | 196 | | // Need to allocate a new array and copy. |
| | 0 | 197 | | while (blockArraySize < blocksNeeded) |
| | 0 | 198 | | { |
| | 0 | 199 | | blockArraySize *= 2; |
| | 0 | 200 | | } |
| | | 201 | | |
| | 0 | 202 | | byte[]?[] newBlockArray = new byte[]?[blockArraySize]; |
| | 0 | 203 | | _blocks.AsSpan((int)unusedInitialBlocks, (int)usedBlocks).CopyTo(newBlockArray); |
| | 0 | 204 | | _blocks = newBlockArray; |
| | 0 | 205 | | } |
| | | 206 | | else |
| | 0 | 207 | | { |
| | | 208 | | // We can shift the array down to make enough space |
| | 0 | 209 | | _blocks.AsSpan((int)unusedInitialBlocks, (int)usedBlocks).CopyTo(_blocks); |
| | | 210 | | |
| | | 211 | | // Null out the part of the array left over from the shift, so that we aren't holding references |
| | 0 | 212 | | _blocks.AsSpan((int)usedBlocks, (int)unusedInitialBlocks).Clear(); |
| | 0 | 213 | | } |
| | | 214 | | |
| | 0 | 215 | | uint shift = unusedInitialBlocks * BlockSize; |
| | 0 | 216 | | _allocatedEnd -= shift; |
| | 0 | 217 | | _activeStart -= shift; |
| | 0 | 218 | | _availableStart -= shift; |
| | | 219 | | |
| | 0 | 220 | | Debug.Assert(_activeStart / BlockSize == 0, $"Start is not in first block after move or resize?? _ac |
| | 0 | 221 | | } |
| | 0 | 222 | | } |
| | | 223 | | |
| | | 224 | | // Allocate new blocks |
| | 0 | 225 | | Debug.Assert(_allocatedEnd % BlockSize == 0); |
| | 0 | 226 | | uint allocatedBlockCount = _allocatedEnd / BlockSize; |
| | 0 | 227 | | Debug.Assert(allocatedBlockCount == 0 || _blocks[allocatedBlockCount - 1] is not null); |
| | 0 | 228 | | for (uint i = 0; i < newBlocksNeeded; i++) |
| | 0 | 229 | | { |
| | 0 | 230 | | Debug.Assert(_blocks[allocatedBlockCount] is null); |
| | 0 | 231 | | _blocks[allocatedBlockCount++] = ArrayPool<byte>.Shared.Rent(BlockSize); |
| | 0 | 232 | | } |
| | | 233 | | |
| | 0 | 234 | | _allocatedEnd = allocatedBlockCount * BlockSize; |
| | | 235 | | |
| | | 236 | | // After all of that, we should have enough available memory now |
| | 0 | 237 | | Debug.Assert(byteCount <= AvailableMemory.Length); |
| | | 238 | | |
| | 0 | 239 | | CheckState(); |
| | 0 | 240 | | } |
| | | 241 | | |
| | | 242 | | [Conditional("DEBUG")] |
| | | 243 | | private void CheckState() |
| | 0 | 244 | | { |
| | 0 | 245 | | if (_blocks == null) |
| | 0 | 246 | | { |
| | 0 | 247 | | Debug.Assert(_activeStart == 0); |
| | 0 | 248 | | Debug.Assert(_availableStart == 0); |
| | 0 | 249 | | Debug.Assert(_allocatedEnd == 0); |
| | 0 | 250 | | } |
| | | 251 | | else |
| | 0 | 252 | | { |
| | 0 | 253 | | Debug.Assert(_activeStart <= _availableStart); |
| | 0 | 254 | | Debug.Assert(_availableStart <= _allocatedEnd); |
| | 0 | 255 | | Debug.Assert(_allocatedEnd <= _blocks.Length * BlockSize); |
| | | 256 | | |
| | 0 | 257 | | Debug.Assert(_allocatedEnd % BlockSize == 0, $"_allocatedEnd={_allocatedEnd} not at block boundary?"); |
| | | 258 | | |
| | 0 | 259 | | uint firstAllocatedBlock = _activeStart / BlockSize; |
| | 0 | 260 | | uint firstUnallocatedBlock = _allocatedEnd / BlockSize; |
| | | 261 | | |
| | 0 | 262 | | for (uint i = 0; i < firstAllocatedBlock; i++) |
| | 0 | 263 | | { |
| | 0 | 264 | | Debug.Assert(_blocks[i] is null); |
| | 0 | 265 | | } |
| | | 266 | | |
| | 0 | 267 | | for (uint i = firstAllocatedBlock; i < firstUnallocatedBlock; i++) |
| | 0 | 268 | | { |
| | 0 | 269 | | Debug.Assert(_blocks[i] is not null); |
| | 0 | 270 | | } |
| | | 271 | | |
| | 0 | 272 | | for (uint i = firstUnallocatedBlock; i < _blocks.Length; i++) |
| | 0 | 273 | | { |
| | 0 | 274 | | Debug.Assert(_blocks[i] is null); |
| | 0 | 275 | | } |
| | | 276 | | |
| | 0 | 277 | | if (_activeStart == _availableStart) |
| | 0 | 278 | | { |
| | 0 | 279 | | Debug.Assert(_activeStart == 0, $"No active bytes but _activeStart={_activeStart}"); |
| | 0 | 280 | | } |
| | 0 | 281 | | } |
| | 0 | 282 | | } |
| | | 283 | | } |
| | | 284 | | |
| | | 285 | | // This is a Memory-like struct for handling multi-array segments from MultiArrayBuffer above. |
| | | 286 | | // It supports standard Span/Memory operations like indexing, Slice, Length, etc |
| | | 287 | | // It also supports CopyTo/CopyFrom Span<byte> |
| | | 288 | | |
| | | 289 | | internal readonly struct MultiMemory |
| | | 290 | | { |
| | | 291 | | private readonly byte[]?[]? _blocks; |
| | | 292 | | private readonly uint _start; |
| | | 293 | | private readonly uint _length; |
| | | 294 | | |
| | | 295 | | private const int BlockSize = 16 * 1024; |
| | | 296 | | |
| | | 297 | | internal MultiMemory(byte[]?[]? blocks, uint start, uint length) |
| | | 298 | | { |
| | | 299 | | if (length == 0) |
| | | 300 | | { |
| | | 301 | | _blocks = null; |
| | | 302 | | _start = 0; |
| | | 303 | | _length = 0; |
| | | 304 | | } |
| | | 305 | | else |
| | | 306 | | { |
| | | 307 | | Debug.Assert(blocks is not null); |
| | | 308 | | Debug.Assert(start <= int.MaxValue); |
| | | 309 | | Debug.Assert(length <= int.MaxValue); |
| | | 310 | | Debug.Assert(start + length <= blocks.Length * BlockSize); |
| | | 311 | | |
| | | 312 | | _blocks = blocks; |
| | | 313 | | _start = start; |
| | | 314 | | _length = length; |
| | | 315 | | } |
| | | 316 | | } |
| | | 317 | | |
| | | 318 | | private static uint GetBlockIndex(uint offset) => offset / BlockSize; |
| | | 319 | | private static uint GetOffsetInBlock(uint offset) => offset % BlockSize; |
| | | 320 | | |
| | | 321 | | public bool IsEmpty => _length == 0; |
| | | 322 | | |
| | | 323 | | public int Length => (int)_length; |
| | | 324 | | |
| | | 325 | | public ref byte this[int index] |
| | | 326 | | { |
| | | 327 | | get |
| | | 328 | | { |
| | | 329 | | uint uindex = (uint)index; |
| | | 330 | | if (uindex >= _length) |
| | | 331 | | { |
| | | 332 | | throw new IndexOutOfRangeException(); |
| | | 333 | | } |
| | | 334 | | |
| | | 335 | | uint offset = _start + uindex; |
| | | 336 | | return ref _blocks![GetBlockIndex(offset)]![GetOffsetInBlock(offset)]; |
| | | 337 | | } |
| | | 338 | | } |
| | | 339 | | |
| | | 340 | | public int BlockCount => (int)(GetBlockIndex(_start + _length + (BlockSize - 1)) - GetBlockIndex(_start)); |
| | | 341 | | |
| | | 342 | | public Memory<byte> GetBlock(int blockIndex) |
| | | 343 | | { |
| | | 344 | | if ((uint)blockIndex >= BlockCount) |
| | | 345 | | { |
| | | 346 | | throw new IndexOutOfRangeException(); |
| | | 347 | | } |
| | | 348 | | |
| | | 349 | | Debug.Assert(_length > 0, "Length should never be 0 here because BlockCount would be 0"); |
| | | 350 | | Debug.Assert(_blocks is not null); |
| | | 351 | | |
| | | 352 | | uint startInBlock = (blockIndex == 0 ? GetOffsetInBlock(_start) : 0); |
| | | 353 | | uint endInBlock = (blockIndex == BlockCount - 1 ? GetOffsetInBlock(_start + _length - 1) + 1 : BlockSize); |
| | | 354 | | |
| | | 355 | | Debug.Assert(0 <= startInBlock, $"Invalid startInBlock={startInBlock}. blockIndex={blockIndex}, _blocks.Leng |
| | | 356 | | Debug.Assert(startInBlock < endInBlock, $"Invalid startInBlock={startInBlock}, endInBlock={endInBlock}. bloc |
| | | 357 | | Debug.Assert(endInBlock <= BlockSize, $"Invalid endInBlock={endInBlock}. blockIndex={blockIndex}, _blocks.Le |
| | | 358 | | |
| | | 359 | | return new Memory<byte>(_blocks[GetBlockIndex(_start) + blockIndex], (int)startInBlock, (int)(endInBlock - s |
| | | 360 | | } |
| | | 361 | | |
| | | 362 | | public MultiMemory Slice(int start) |
| | | 363 | | { |
| | | 364 | | uint ustart = (uint)start; |
| | | 365 | | if (ustart > _length) |
| | | 366 | | { |
| | | 367 | | throw new IndexOutOfRangeException(); |
| | | 368 | | } |
| | | 369 | | |
| | | 370 | | return new MultiMemory(_blocks, _start + ustart, _length - ustart); |
| | | 371 | | } |
| | | 372 | | |
| | | 373 | | public MultiMemory Slice(int start, int length) |
| | | 374 | | { |
| | | 375 | | uint ustart = (uint)start; |
| | | 376 | | uint ulength = (uint)length; |
| | | 377 | | if (ustart > _length || ulength > _length - ustart) |
| | | 378 | | { |
| | | 379 | | throw new IndexOutOfRangeException(); |
| | | 380 | | } |
| | | 381 | | |
| | | 382 | | return new MultiMemory(_blocks, _start + ustart, ulength); |
| | | 383 | | } |
| | | 384 | | |
| | | 385 | | public void CopyTo(Span<byte> destination) |
| | | 386 | | { |
| | | 387 | | if (destination.Length < _length) |
| | | 388 | | { |
| | | 389 | | throw new ArgumentOutOfRangeException(nameof(destination)); |
| | | 390 | | } |
| | | 391 | | |
| | | 392 | | int blockCount = BlockCount; |
| | | 393 | | for (int blockIndex = 0; blockIndex < blockCount; blockIndex++) |
| | | 394 | | { |
| | | 395 | | Memory<byte> block = GetBlock(blockIndex); |
| | | 396 | | block.Span.CopyTo(destination); |
| | | 397 | | destination = destination.Slice(block.Length); |
| | | 398 | | } |
| | | 399 | | } |
| | | 400 | | |
| | | 401 | | public void CopyFrom(ReadOnlySpan<byte> source) |
| | | 402 | | { |
| | | 403 | | if (_length < source.Length) |
| | | 404 | | { |
| | | 405 | | throw new ArgumentOutOfRangeException(nameof(source)); |
| | | 406 | | } |
| | | 407 | | |
| | | 408 | | int blockCount = BlockCount; |
| | | 409 | | for (int blockIndex = 0; blockIndex < blockCount; blockIndex++) |
| | | 410 | | { |
| | | 411 | | Memory<byte> block = GetBlock(blockIndex); |
| | | 412 | | |
| | | 413 | | if (source.Length <= block.Length) |
| | | 414 | | { |
| | | 415 | | source.CopyTo(block.Span); |
| | | 416 | | break; |
| | | 417 | | } |
| | | 418 | | |
| | | 419 | | source.Slice(0, block.Length).CopyTo(block.Span); |
| | | 420 | | source = source.Slice(block.Length); |
| | | 421 | | } |
| | | 422 | | } |
| | | 423 | | |
| | | 424 | | public static MultiMemory Empty => default; |
| | | 425 | | } |
| | | 426 | | } |