-
-
Notifications
You must be signed in to change notification settings - Fork 447
/
CharacterMap.cs
301 lines (270 loc) · 11 KB
/
CharacterMap.cs
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
// Copyright (c) Alexandre Mutel. All rights reserved.
// This file is licensed under the BSD-Clause 2 license.
// See the license.txt file in the project root for more information.
using System;
using System.Collections.Generic;
using System.Diagnostics;
using System.Linq;
using System.Runtime.CompilerServices;
#if NETCOREAPP3_1_OR_GREATER
using System.Numerics;
using System.Runtime.Intrinsics;
using System.Runtime.Intrinsics.X86;
#endif
namespace Markdig.Helpers
{
/// <summary>
/// Allows to associate characters to a data structures and query efficiently for them.
/// </summary>
/// <typeparam name="T"></typeparam>
public sealed class CharacterMap<T> where T : class
{
#if NETCOREAPP3_1_OR_GREATER
private readonly Vector128<byte> _asciiBitmap;
#endif
private readonly T[] asciiMap;
private readonly Dictionary<uint, T>? nonAsciiMap;
private readonly BoolVector128 isOpeningCharacter;
/// <summary>
/// Initializes a new instance of the <see cref="CharacterMap{T}"/> class.
/// </summary>
/// <param name="maps">The states.</param>
/// <exception cref="ArgumentNullException"></exception>
public CharacterMap(IEnumerable<KeyValuePair<char, T>> maps)
{
if (maps is null) ThrowHelper.ArgumentNullException(nameof(maps));
var charSet = new HashSet<char>();
int maxChar = 0;
foreach (var map in maps)
{
var openingChar = map.Key;
charSet.Add(openingChar);
if (openingChar < 128)
{
maxChar = Math.Max(maxChar, openingChar);
if (openingChar == 0)
{
ThrowHelper.ArgumentOutOfRangeException("Null is not a valid opening character.", nameof(maps));
}
}
else
{
nonAsciiMap ??= new Dictionary<uint, T>();
}
}
OpeningCharacters = charSet.ToArray();
Array.Sort(OpeningCharacters);
asciiMap = new T[maxChar + 1];
foreach (var state in maps)
{
char openingChar = state.Key;
if (openingChar < 128)
{
asciiMap[openingChar] ??= state.Value;
isOpeningCharacter.Set(openingChar);
}
else if (!nonAsciiMap!.ContainsKey(openingChar))
{
nonAsciiMap[openingChar] = state.Value;
}
}
#if NETCOREAPP3_1_OR_GREATER
if (nonAsciiMap is null)
{
long bitmap_0_3 = 0;
long bitmap_4_7 = 0;
foreach (char openingChar in OpeningCharacters)
{
int position = (openingChar >> 4) | ((openingChar & 0x0F) << 3);
if (position < 64) bitmap_0_3 |= 1L << position;
else bitmap_4_7 |= 1L << (position - 64);
}
_asciiBitmap = Vector128.Create(bitmap_0_3, bitmap_4_7).AsByte();
}
#endif
}
/// <summary>
/// Gets all the opening characters defined.
/// </summary>
public char[] OpeningCharacters { get; }
/// <summary>
/// Gets the list of parsers valid for the specified opening character.
/// </summary>
/// <param name="openingChar">The opening character.</param>
/// <returns>A list of parsers valid for the specified opening character or null if no parsers registered.</returns>
public T? this[uint openingChar]
{
[MethodImpl(MethodImplOptions.AggressiveInlining)]
get
{
T[] asciiMap = this.asciiMap;
if (openingChar < (uint)asciiMap.Length)
{
return asciiMap[openingChar];
}
else
{
T? map = null;
nonAsciiMap?.TryGetValue(openingChar, out map);
return map;
}
}
}
/// <summary>
/// Searches for an opening character from a registered parser in the specified string.
/// </summary>
/// <param name="text">The text.</param>
/// <param name="start">The start.</param>
/// <param name="end">The end.</param>
/// <returns>Index position within the string of the first opening character found in the specified text; if not found, returns -1</returns>
public int IndexOfOpeningCharacter(string text, int start, int end)
{
Debug.Assert(text is not null);
Debug.Assert(start >= 0 && end >= 0);
Debug.Assert(end - start + 1 >= 0);
Debug.Assert(end - start + 1 <= text.Length);
if (nonAsciiMap is null)
{
#if NETCOREAPP3_1_OR_GREATER
if (Ssse3.IsSupported && BitConverter.IsLittleEndian)
{
// Based on http://0x80.pl/articles/simd-byte-lookup.html#universal-algorithm
// Optimized for sets in the [1, 127] range
int lengthMinusOne = end - start;
int charsToProcessVectorized = lengthMinusOne & ~(2 * Vector128<short>.Count - 1);
int finalStart = start + charsToProcessVectorized;
if (start < finalStart)
{
ref char textStartRef = ref Unsafe.Add(ref Unsafe.AsRef(in text.GetPinnableReference()), start);
Vector128<byte> bitmap = _asciiBitmap;
do
{
// Load 32 bytes (16 chars) into two Vector128<short>s (chars)
// Drop the high byte of each char
// Pack the remaining bytes into a single Vector128<byte>
Vector128<byte> input = Sse2.PackUnsignedSaturate(
Unsafe.ReadUnaligned<Vector128<short>>(ref Unsafe.As<char, byte>(ref textStartRef)),
Unsafe.ReadUnaligned<Vector128<short>>(ref Unsafe.As<char, byte>(ref Unsafe.Add(ref textStartRef, Vector128<short>.Count))));
// Extract the higher nibble of each character ((input >> 4) & 0xF)
Vector128<byte> higherNibbles = Sse2.And(Sse2.ShiftRightLogical(input.AsUInt16(), 4).AsByte(), Vector128.Create((byte)0xF));
// Lookup the matching higher nibble for each character based on the lower nibble
// PSHUFB will set the result to 0 for any non-ASCII (> 127) character
Vector128<byte> bitsets = Ssse3.Shuffle(bitmap, input);
// Calculate a bitmask (1 << (higherNibble % 8)) for each character
Vector128<byte> bitmask = Ssse3.Shuffle(Vector128.Create(0x8040201008040201).AsByte(), higherNibbles);
// Check which characters are present in the set
// We are relying on bitsets being zero for non-ASCII characters
Vector128<byte> result = Sse2.And(bitsets, bitmask);
if (!result.Equals(Vector128<byte>.Zero))
{
int resultMask = ~Sse2.MoveMask(Sse2.CompareEqual(result, Vector128<byte>.Zero));
return start + BitOperations.TrailingZeroCount((uint)resultMask);
}
start += 2 * Vector128<short>.Count;
textStartRef = ref Unsafe.Add(ref textStartRef, 2 * Vector128<short>.Count);
}
while (start != finalStart);
}
}
ref char textRef = ref Unsafe.AsRef(in text.GetPinnableReference());
for (; start <= end; start++)
{
if (IntPtr.Size == 4)
{
uint c = Unsafe.Add(ref textRef, start);
if (c < 128 && isOpeningCharacter[c])
{
return start;
}
}
else
{
ulong c = Unsafe.Add(ref textRef, start);
if (c < 128 && isOpeningCharacter[c])
{
return start;
}
}
}
#else
unsafe
{
fixed (char* pText = text)
{
for (int i = start; i <= end; i++)
{
char c = pText[i];
if (c < 128 && isOpeningCharacter[c])
{
return i;
}
}
}
}
#endif
return -1;
}
else
{
return IndexOfOpeningCharacterNonAscii(text, start, end);
}
}
private int IndexOfOpeningCharacterNonAscii(string text, int start, int end)
{
#if NETCOREAPP3_1_OR_GREATER
ref char textRef = ref Unsafe.AsRef(in text.GetPinnableReference());
for (int i = start; i <= end; i++)
{
char c = Unsafe.Add(ref textRef, i);
if (c < 128 ? isOpeningCharacter[c] : nonAsciiMap!.ContainsKey(c))
{
return i;
}
}
#else
unsafe
{
fixed (char* pText = text)
{
for (int i = start; i <= end; i++)
{
char c = pText[i];
if (c < 128 ? isOpeningCharacter[c] : nonAsciiMap!.ContainsKey(c))
{
return i;
}
}
}
}
#endif
return -1;
}
}
internal unsafe struct BoolVector128
{
private fixed bool values[128];
public void Set(char c)
{
Debug.Assert(c < 128);
values[c] = true;
}
public readonly bool this[uint c]
{
[MethodImpl(MethodImplOptions.AggressiveInlining)]
get
{
Debug.Assert(c < 128);
return values[c];
}
}
public readonly bool this[ulong c]
{
[MethodImpl(MethodImplOptions.AggressiveInlining)]
get
{
Debug.Assert(c < 128 && IntPtr.Size == 8);
return values[c];
}
}
}
}