| | 1 | | using System.Buffers; |
| | 2 | | using System.Buffers.Binary; |
| | 3 | | using System.Runtime.CompilerServices; |
| | 4 | |
|
| | 5 | | namespace NLightning.Domain.Utils; |
| | 6 | |
|
| | 7 | | using Interfaces; |
| | 8 | |
|
| | 9 | | public class BitWriter : IBitWriter |
| | 10 | | { |
| | 11 | | private int _bitOffset; |
| | 12 | | private byte[] _buffer; |
| | 13 | |
|
| 6428 | 14 | | public int TotalBits { get; private set; } |
| | 15 | |
|
| 228 | 16 | | public BitWriter(int totalBits) |
| | 17 | | { |
| 228 | 18 | | if (totalBits < 0) |
| 0 | 19 | | throw new ArgumentOutOfRangeException(nameof(totalBits), "Must be >= 0."); |
| | 20 | |
|
| 228 | 21 | | TotalBits = totalBits; |
| 228 | 22 | | var totalBytes = (totalBits + 7) / 8; |
| 228 | 23 | | _buffer = ArrayPool<byte>.Shared.Rent(totalBytes); |
| 228 | 24 | | Array.Clear(_buffer, 0, totalBytes); |
| 228 | 25 | | } |
| | 26 | |
|
| | 27 | | public void GrowByBits(int additionalBits) |
| | 28 | | { |
| 4 | 29 | | var requiredBits = _bitOffset + additionalBits; |
| 4 | 30 | | if (requiredBits <= TotalBits) |
| 0 | 31 | | return; |
| | 32 | |
|
| 4 | 33 | | var newTotalBits = Math.Max(TotalBits * 2, requiredBits); |
| 4 | 34 | | var newByteCount = (newTotalBits + 7) / 8; |
| | 35 | |
|
| 4 | 36 | | Array.Resize(ref _buffer, newByteCount); |
| 4 | 37 | | TotalBits = requiredBits; |
| 4 | 38 | | } |
| | 39 | |
|
| | 40 | | [MethodImpl(MethodImplOptions.AggressiveInlining)] |
| | 41 | | public void WriteBits(ReadOnlySpan<byte> value, int bitLength) |
| | 42 | | { |
| 1200 | 43 | | WriteBits(value, 0, bitLength); |
| 1200 | 44 | | } |
| | 45 | |
|
| | 46 | | [MethodImpl(MethodImplOptions.AggressiveInlining)] |
| | 47 | | public void WriteBits(ReadOnlySpan<byte> value, int valueOffset, int bitLength) |
| | 48 | | { |
| 1200 | 49 | | if (_bitOffset + bitLength > TotalBits) |
| 0 | 50 | | throw new InvalidOperationException( |
| 0 | 51 | | $"Not enough bits to write {bitLength}. Offset={_bitOffset}, capacity={TotalBits}."); |
| | 52 | |
|
| 1200 | 53 | | var byteOffset = _bitOffset / 8; |
| 1200 | 54 | | var shift = _bitOffset % 8; |
| | 55 | |
|
| 1200 | 56 | | var bytesNeeded = (bitLength + 7) / 8; |
| | 57 | |
|
| 1200 | 58 | | if (shift == 0) |
| | 59 | | { |
| 7304 | 60 | | for (var i = 0; i < bytesNeeded; i++) |
| | 61 | | { |
| 3244 | 62 | | byte b = 0; |
| 3244 | 63 | | if (valueOffset + i < value.Length) |
| 3184 | 64 | | b = value[valueOffset + i]; |
| | 65 | |
|
| 3244 | 66 | | _buffer[byteOffset + i] = b; |
| | 67 | | } |
| | 68 | | } |
| | 69 | | else |
| | 70 | | { |
| 15200 | 71 | | for (var i = 0; i < bytesNeeded; i++) |
| | 72 | | { |
| 6808 | 73 | | byte current = 0; |
| 6808 | 74 | | if (valueOffset + i < value.Length) |
| 6696 | 75 | | current = value[valueOffset + i]; |
| | 76 | |
|
| 6808 | 77 | | var left = (byte)(current >> shift); |
| 6808 | 78 | | _buffer[byteOffset + i] |= left; |
| | 79 | |
|
| 6808 | 80 | | var nextIndex = byteOffset + i + 1; |
| | 81 | |
|
| 6808 | 82 | | if (nextIndex >= _buffer.Length) continue; |
| | 83 | |
|
| 6808 | 84 | | var right = (byte)(current << (8 - shift)); |
| 6808 | 85 | | _buffer[nextIndex] |= right; |
| | 86 | | } |
| | 87 | | } |
| | 88 | |
|
| 1200 | 89 | | _bitOffset += bitLength; |
| 1200 | 90 | | } |
| | 91 | |
|
| | 92 | | public void WriteBit(bool bit) |
| | 93 | | { |
| 2352 | 94 | | if (_bitOffset >= TotalBits) |
| 4 | 95 | | throw new InvalidOperationException("No more bits to write."); |
| | 96 | |
|
| 2348 | 97 | | var byteIndex = _bitOffset / 8; |
| 2348 | 98 | | var bitIndex = _bitOffset % 8; |
| 2348 | 99 | | var shift = 7 - bitIndex; |
| | 100 | |
|
| 2348 | 101 | | if (bit) |
| 164 | 102 | | _buffer[byteIndex] |= (byte)(1 << shift); |
| | 103 | | else |
| 2184 | 104 | | _buffer[byteIndex] &= (byte)~(1 << shift); |
| | 105 | |
|
| 2348 | 106 | | _bitOffset++; |
| 2348 | 107 | | } |
| | 108 | |
|
| | 109 | | public void WriteByteAsBits(byte value, int bits) |
| | 110 | | { |
| | 111 | | const byte byteBitSize = sizeof(byte) * 8; |
| 340 | 112 | | if (bits is < 1 or > byteBitSize) |
| 0 | 113 | | throw new ArgumentOutOfRangeException(nameof(bits), $"must be between 1 and {byteBitSize}."); |
| | 114 | |
|
| 340 | 115 | | var masked = value & (byte)((1 << bits) - 1); |
| 340 | 116 | | var shifted = (byte)(masked << (byteBitSize - bits)); |
| | 117 | |
|
| 340 | 118 | | Span<byte> bytes = stackalloc byte[sizeof(byte)]; |
| 340 | 119 | | bytes[0] = shifted; |
| | 120 | |
|
| 340 | 121 | | WriteBits(bytes, bits); |
| 340 | 122 | | } |
| | 123 | |
|
| | 124 | | public void WriteInt16AsBits(short value, int bits, bool bigEndian = true) |
| | 125 | | { |
| | 126 | | const byte shortBitSize = sizeof(short) * 8; |
| 324 | 127 | | if (bits is < 1 or > shortBitSize) |
| 0 | 128 | | throw new ArgumentOutOfRangeException(nameof(bits), $"must be between 1 and {shortBitSize}."); |
| | 129 | |
|
| 324 | 130 | | var masked = value & (short)((1 >> bits) - 1); |
| 324 | 131 | | var shifted = (short)(masked << (shortBitSize - bits)); |
| | 132 | |
|
| 324 | 133 | | Span<byte> bytes = stackalloc byte[sizeof(short)]; |
| 324 | 134 | | BinaryPrimitives.WriteInt16LittleEndian(bytes, shifted); |
| | 135 | |
|
| 324 | 136 | | if ((bigEndian && BitConverter.IsLittleEndian) || (!bigEndian && !BitConverter.IsLittleEndian)) |
| 324 | 137 | | bytes.Reverse(); |
| | 138 | |
|
| 324 | 139 | | WriteBits(bytes, bits); |
| 324 | 140 | | } |
| | 141 | |
|
| | 142 | | public void WriteUInt16AsBits(ushort value, int bits, bool bigEndian = true) |
| | 143 | | { |
| | 144 | | const byte ushortBitSize = sizeof(ushort) * 8; |
| 24 | 145 | | if (bits is < 1 or > ushortBitSize) |
| 0 | 146 | | throw new ArgumentOutOfRangeException(nameof(bits), $"must be between 1 and {ushortBitSize}."); |
| | 147 | |
|
| 24 | 148 | | var masked = value & (ushort)((1 << bits) - 1); |
| 24 | 149 | | var shifted = (ushort)(masked << (ushortBitSize - bits)); |
| | 150 | |
|
| 24 | 151 | | Span<byte> bytes = stackalloc byte[sizeof(ushort)]; |
| 24 | 152 | | BinaryPrimitives.WriteUInt16LittleEndian(bytes, shifted); |
| | 153 | |
|
| 24 | 154 | | if ((bigEndian && BitConverter.IsLittleEndian) || (!bigEndian && !BitConverter.IsLittleEndian)) |
| 24 | 155 | | bytes.Reverse(); |
| | 156 | |
|
| 24 | 157 | | WriteBits(bytes, bits); |
| 24 | 158 | | } |
| | 159 | |
|
| | 160 | | public void WriteInt32AsBits(int value, int bits, bool bigEndian = true) |
| | 161 | | { |
| | 162 | | const byte intBitSize = sizeof(int) * 8; |
| 92 | 163 | | if (bits is < 1 or > intBitSize) |
| 0 | 164 | | throw new ArgumentOutOfRangeException(nameof(bits), $"must be between 1 and {intBitSize}."); |
| | 165 | |
|
| 92 | 166 | | var masked = value & (int)((1L << bits) - 1); |
| 92 | 167 | | var shifted = masked << (intBitSize - bits); |
| | 168 | |
|
| 92 | 169 | | Span<byte> bytes = stackalloc byte[sizeof(int)]; |
| 92 | 170 | | BinaryPrimitives.WriteInt32LittleEndian(bytes, shifted); |
| | 171 | |
|
| 92 | 172 | | if ((bigEndian && BitConverter.IsLittleEndian) || (!bigEndian && !BitConverter.IsLittleEndian)) |
| 92 | 173 | | bytes.Reverse(); |
| | 174 | |
|
| 92 | 175 | | WriteBits(bytes, bits); |
| 92 | 176 | | } |
| | 177 | |
|
| | 178 | | public void WriteInt64AsBits(long value, int bits, bool bigEndian = true) |
| | 179 | | { |
| | 180 | | const byte longBitSize = sizeof(long) * 8; |
| 72 | 181 | | if (bits is < 1 or > longBitSize) |
| 0 | 182 | | throw new ArgumentOutOfRangeException(nameof(bits), $"must be between 1 and {longBitSize}."); |
| | 183 | |
|
| 72 | 184 | | var masked = value & (long)((1UL << bits) - 1); |
| 72 | 185 | | var shifted = masked << (longBitSize - bits); |
| | 186 | |
|
| 72 | 187 | | Span<byte> bytes = stackalloc byte[sizeof(long)]; |
| 72 | 188 | | BinaryPrimitives.WriteInt64LittleEndian(bytes, shifted); |
| | 189 | |
|
| 72 | 190 | | if ((bigEndian && BitConverter.IsLittleEndian) || (!bigEndian && !BitConverter.IsLittleEndian)) |
| 72 | 191 | | bytes.Reverse(); |
| | 192 | |
|
| 72 | 193 | | WriteBits(bytes, bits); |
| 72 | 194 | | } |
| | 195 | |
|
| | 196 | | public bool HasMoreBits(int requiredBits) |
| | 197 | | { |
| 2272 | 198 | | return _bitOffset + requiredBits <= TotalBits; |
| | 199 | | } |
| | 200 | |
|
| | 201 | | public void SkipBits(int v) |
| | 202 | | { |
| 0 | 203 | | _bitOffset += v; |
| 0 | 204 | | } |
| | 205 | |
|
| | 206 | | public byte[] ToArray() |
| | 207 | | { |
| 284 | 208 | | var bytes = new byte[(TotalBits + 7) / 8]; |
| 37648 | 209 | | for (var i = 0; i < bytes.Length; i++) |
| 18540 | 210 | | bytes[i] = _buffer[i]; |
| | 211 | |
|
| 284 | 212 | | return bytes; |
| | 213 | | } |
| | 214 | |
|
| | 215 | | public void Dispose() |
| | 216 | | { |
| 0 | 217 | | ArrayPool<byte>.Shared.Return(_buffer); |
| 0 | 218 | | } |
| | 219 | | } |