| | | 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 | | using System.Runtime.CompilerServices; |
| | | 7 | | using System.Runtime.InteropServices; |
| | | 8 | | using Microsoft.Win32.SafeHandles; |
| | | 9 | | |
| | | 10 | | namespace System.IO.Compression |
| | | 11 | | { |
| | | 12 | | /// <summary>Represents a Zstandard compression dictionary.</summary> |
| | | 13 | | [System.Runtime.Versioning.UnsupportedOSPlatform("browser")] |
| | | 14 | | public sealed class ZstandardDictionary : IDisposable |
| | | 15 | | { |
| | | 16 | | private readonly SafeZstdCDictHandle _compressionDictionary; |
| | | 17 | | private readonly SafeZstdDDictHandle _decompressionDictionary; |
| | | 18 | | private readonly byte[] _dictionaryData; |
| | | 19 | | private bool _disposed; |
| | | 20 | | |
| | 0 | 21 | | private ZstandardDictionary(SafeZstdCDictHandle compressionDict, SafeZstdDDictHandle decompressionDict, byte[] d |
| | 0 | 22 | | { |
| | 0 | 23 | | _compressionDictionary = compressionDict; |
| | 0 | 24 | | _decompressionDictionary = decompressionDict; |
| | 0 | 25 | | _dictionaryData = data; |
| | 0 | 26 | | } |
| | | 27 | | |
| | | 28 | | /// <summary>Creates a Zstandard dictionary from the specified buffer.</summary> |
| | | 29 | | /// <param name="buffer">The buffer containing the dictionary data.</param> |
| | | 30 | | /// <returns>A new <see cref="ZstandardDictionary"/> instance.</returns> |
| | | 31 | | /// <exception cref="ArgumentException">The buffer is empty.</exception> |
| | 0 | 32 | | public static ZstandardDictionary Create(ReadOnlySpan<byte> buffer) => Create(buffer, ZstandardUtils.Quality_Def |
| | | 33 | | |
| | | 34 | | /// <summary>Creates a Zstandard dictionary from the specified buffer with the specified quality level and dicti |
| | | 35 | | /// <param name="buffer">The buffer containing the dictionary data.</param> |
| | | 36 | | /// <param name="quality">The quality level for dictionary creation.</param> |
| | | 37 | | /// <returns>A new <see cref="ZstandardDictionary"/> instance.</returns> |
| | | 38 | | /// <exception cref="ArgumentException">The buffer is empty.</exception> |
| | | 39 | | /// <exception cref="IOException">Failed to create the <see cref="ZstandardDictionary"/> instance.</exception> |
| | | 40 | | public static ZstandardDictionary Create(ReadOnlySpan<byte> buffer, int quality) |
| | 0 | 41 | | { |
| | 0 | 42 | | if (buffer.IsEmpty) |
| | 0 | 43 | | { |
| | 0 | 44 | | throw new ArgumentException(SR.ZstandardDictionary_EmptyBuffer, nameof(buffer)); |
| | | 45 | | } |
| | | 46 | | |
| | 0 | 47 | | byte[] data = buffer.ToArray(); |
| | | 48 | | |
| | | 49 | | |
| | | 50 | | unsafe |
| | 0 | 51 | | { |
| | 0 | 52 | | fixed (byte* dictPtr = data) |
| | 0 | 53 | | { |
| | 0 | 54 | | SafeZstdCDictHandle compressionDict = Interop.Zstd.ZSTD_createCDict_byReference(dictPtr, (nuint)data |
| | | 55 | | |
| | 0 | 56 | | if (compressionDict.IsInvalid) |
| | 0 | 57 | | { |
| | 0 | 58 | | throw new IOException(SR.ZstandardDictionary_CreateCompressionFailed); |
| | | 59 | | } |
| | 0 | 60 | | compressionDict._pinnedData = new PinnedGCHandle<byte[]>(data); |
| | | 61 | | |
| | 0 | 62 | | SafeZstdDDictHandle decompressionDict = Interop.Zstd.ZSTD_createDDict_byReference(dictPtr, (nuint)da |
| | | 63 | | |
| | 0 | 64 | | if (decompressionDict.IsInvalid) |
| | 0 | 65 | | { |
| | 0 | 66 | | compressionDict.Dispose(); |
| | 0 | 67 | | throw new IOException(SR.ZstandardDictionary_CreateDecompressionFailed); |
| | | 68 | | } |
| | 0 | 69 | | decompressionDict._pinnedData = new PinnedGCHandle<byte[]>(data); |
| | | 70 | | |
| | 0 | 71 | | return new ZstandardDictionary(compressionDict, decompressionDict, data); |
| | | 72 | | } |
| | | 73 | | } |
| | 0 | 74 | | } |
| | | 75 | | |
| | | 76 | | /// <summary>Trains Zstandard dictionary data using the provided samples.</summary> |
| | | 77 | | /// <param name="samples">All training samples concatenated in one large buffer.</param> |
| | | 78 | | /// <param name="sampleLengths">The lengths of the individual samples. The sum of these lengths must equal the l |
| | | 79 | | /// <param name="maxDictionarySize">The maximum size of the dictionary to create.</param> |
| | | 80 | | /// <returns>A byte array containing the trained dictionary data.</returns> |
| | | 81 | | /// <exception cref="ArgumentException">The sample data or lengths are invalid.</exception> |
| | | 82 | | /// <exception cref="ArgumentOutOfRangeException"><paramref name="maxDictionarySize"/> is less than 256.</except |
| | | 83 | | /// <exception cref="IOException">Failed to train the dictionary.</exception> |
| | | 84 | | /// <remarks> |
| | | 85 | | /// The recommended maximum dictionary size is 100 KB, and the size of the training data |
| | | 86 | | /// should be approximately 100 times the size of the resulting dictionary. |
| | | 87 | | /// The returned data can be stored for later use. Call <see cref="Create(ReadOnlySpan{byte})"/> |
| | | 88 | | /// or <see cref="Create(ReadOnlySpan{byte}, int)"/> to prepare a dictionary for compression or decompression. |
| | | 89 | | /// Specify compression quality when creating the dictionary; its quality takes precedence over |
| | | 90 | | /// <see cref="ZstandardCompressionOptions.Quality"/>. |
| | | 91 | | /// </remarks> |
| | | 92 | | /// <example> |
| | | 93 | | /// <code language="csharp"> |
| | | 94 | | /// byte[] dictionaryData = ZstandardDictionary.Train(samples, sampleLengths, maxDictionarySize); |
| | | 95 | | /// using ZstandardDictionary dictionary = ZstandardDictionary.Create(dictionaryData, quality); |
| | | 96 | | /// </code> |
| | | 97 | | /// </example> |
| | | 98 | | public static byte[] Train(ReadOnlySpan<byte> samples, ReadOnlySpan<int> sampleLengths, int maxDictionarySize) |
| | 0 | 99 | | { |
| | 0 | 100 | | if (samples.IsEmpty) |
| | 0 | 101 | | { |
| | 0 | 102 | | throw new ArgumentException(SR.ZstandardDictionary_EmptyBuffer, nameof(samples)); |
| | | 103 | | } |
| | | 104 | | |
| | | 105 | | // this requirement is enforced by zstd native library, probably due to the underlying algorithm design |
| | 0 | 106 | | if (sampleLengths.Length < 5) |
| | 0 | 107 | | { |
| | 0 | 108 | | throw new ArgumentException(SR.Format(SR.ZstandardDictionary_Train_MinimumSampleCount, 5), nameof(sample |
| | | 109 | | } |
| | | 110 | | |
| | | 111 | | // the lengths need to be converted to nuint for the native call. Rent appropriately sized array from pool |
| | | 112 | | // This incidentally also protects against concurrent modifications of the sampleLengths that could cause |
| | | 113 | | // access violations later in native code. |
| | 0 | 114 | | byte[] lengthsArray = ArrayPool<byte>.Shared.Rent(sampleLengths.Length * sizeof(nuint)); |
| | 0 | 115 | | byte[]? dictionaryBuffer = null; |
| | | 116 | | try |
| | 0 | 117 | | { |
| | 0 | 118 | | Span<nuint> lengthsAsNuint = MemoryMarshal.Cast<byte, nuint>(lengthsArray.AsSpan(0, sampleLengths.Length |
| | 0 | 119 | | Debug.Assert(lengthsAsNuint.Length == sampleLengths.Length); |
| | | 120 | | |
| | | 121 | | const double TrainingSplitPoint = 0.75; |
| | | 122 | | const int MinimumTrainingBytes = 8; |
| | 0 | 123 | | int trainingSampleCount = (int)(sampleLengths.Length * TrainingSplitPoint); |
| | 0 | 124 | | long trainingLength = 0; |
| | 0 | 125 | | long totalLength = 0; |
| | 0 | 126 | | for (int i = 0; i < sampleLengths.Length; i++) |
| | 0 | 127 | | { |
| | 0 | 128 | | int length = sampleLengths[i]; |
| | 0 | 129 | | if (length <= 0) |
| | 0 | 130 | | { |
| | 0 | 131 | | throw new ArgumentException(SR.ZstandardDictionary_Train_InvalidSampleLength, nameof(sampleLengt |
| | | 132 | | } |
| | 0 | 133 | | totalLength += length; |
| | 0 | 134 | | if (i < trainingSampleCount) |
| | 0 | 135 | | { |
| | 0 | 136 | | trainingLength += length; |
| | 0 | 137 | | } |
| | 0 | 138 | | lengthsAsNuint[i] = (nuint)length; |
| | 0 | 139 | | } |
| | | 140 | | |
| | 0 | 141 | | if (totalLength != samples.Length) |
| | 0 | 142 | | { |
| | 0 | 143 | | throw new ArgumentException(SR.ZstandardDictionary_SampleLengthsMismatch, nameof(sampleLengths)); |
| | | 144 | | } |
| | | 145 | | |
| | 0 | 146 | | ArgumentOutOfRangeException.ThrowIfLessThan(maxDictionarySize, 256, nameof(maxDictionarySize)); |
| | | 147 | | |
| | | 148 | | // zstd checks the total size, but its 75% training subset must contain at least 8 bytes to avoid underf |
| | | 149 | | // Remove this workaround once https://github.com/facebook/zstd/issues/4827 is fixed in the bundled vers |
| | 0 | 150 | | if (trainingLength < MinimumTrainingBytes) |
| | 0 | 151 | | { |
| | 0 | 152 | | ZstandardUtils.Throw(Interop.Zstd.ZSTD_error.srcSize_wrong); |
| | | 153 | | } |
| | | 154 | | |
| | 0 | 155 | | dictionaryBuffer = ArrayPool<byte>.Shared.Rent(maxDictionarySize); |
| | | 156 | | nuint dictSize; |
| | | 157 | | |
| | | 158 | | unsafe |
| | 0 | 159 | | { |
| | 0 | 160 | | fixed (byte* samplesPtr = &MemoryMarshal.GetReference(samples)) |
| | 0 | 161 | | fixed (byte* dictPtr = dictionaryBuffer) |
| | 0 | 162 | | fixed (nuint* lengthsAsNuintPtr = &MemoryMarshal.GetReference(lengthsAsNuint)) |
| | 0 | 163 | | { |
| | 0 | 164 | | dictSize = Interop.Zstd.ZDICT_trainFromBuffer( |
| | 0 | 165 | | dictPtr, (nuint)maxDictionarySize, |
| | 0 | 166 | | samplesPtr, lengthsAsNuintPtr, (uint)sampleLengths.Length); |
| | 0 | 167 | | } |
| | | 168 | | |
| | 0 | 169 | | ZstandardUtils.ThrowIfError(dictSize); |
| | 0 | 170 | | return dictionaryBuffer.AsSpan(0, (int)dictSize).ToArray(); |
| | | 171 | | } |
| | | 172 | | } |
| | | 173 | | finally |
| | 0 | 174 | | { |
| | 0 | 175 | | if (dictionaryBuffer is not null) |
| | 0 | 176 | | { |
| | 0 | 177 | | ArrayPool<byte>.Shared.Return(dictionaryBuffer); |
| | 0 | 178 | | } |
| | 0 | 179 | | ArrayPool<byte>.Shared.Return(lengthsArray); |
| | 0 | 180 | | } |
| | 0 | 181 | | } |
| | | 182 | | |
| | | 183 | | /// <summary>Gets the compression dictionary handle.</summary> |
| | | 184 | | internal SafeZstdCDictHandle CompressionDictionary |
| | | 185 | | { |
| | | 186 | | get |
| | 0 | 187 | | { |
| | 0 | 188 | | ThrowIfDisposed(); |
| | 0 | 189 | | return _compressionDictionary; |
| | 0 | 190 | | } |
| | | 191 | | } |
| | | 192 | | |
| | | 193 | | /// <summary>Gets the decompression dictionary handle.</summary> |
| | | 194 | | internal SafeZstdDDictHandle DecompressionDictionary |
| | | 195 | | { |
| | | 196 | | get |
| | 0 | 197 | | { |
| | 0 | 198 | | ThrowIfDisposed(); |
| | 0 | 199 | | return _decompressionDictionary; |
| | 0 | 200 | | } |
| | | 201 | | } |
| | | 202 | | |
| | | 203 | | /// <summary>Gets the dictionary data.</summary> |
| | | 204 | | /// <value>The raw dictionary bytes.</value> |
| | | 205 | | public ReadOnlyMemory<byte> Data |
| | | 206 | | { |
| | | 207 | | get |
| | 0 | 208 | | { |
| | 0 | 209 | | ThrowIfDisposed(); |
| | 0 | 210 | | return _dictionaryData; |
| | 0 | 211 | | } |
| | | 212 | | } |
| | | 213 | | |
| | | 214 | | /// <summary>Releases all resources used by the <see cref="ZstandardDictionary"/>.</summary> |
| | | 215 | | public void Dispose() |
| | 0 | 216 | | { |
| | 0 | 217 | | if (!_disposed) |
| | 0 | 218 | | { |
| | 0 | 219 | | _compressionDictionary.Dispose(); |
| | 0 | 220 | | _decompressionDictionary.Dispose(); |
| | 0 | 221 | | _disposed = true; |
| | 0 | 222 | | } |
| | 0 | 223 | | } |
| | | 224 | | |
| | | 225 | | private void ThrowIfDisposed() |
| | 0 | 226 | | { |
| | 0 | 227 | | ObjectDisposedException.ThrowIf(_disposed, this); |
| | 0 | 228 | | } |
| | | 229 | | } |
| | | 230 | | } |