| | | 1 | | //======================================================================= |
| | | 2 | | // SwiftArraySortHelper.cs |
| | | 3 | | //======================================================================= |
| | | 4 | | // MIT License, Copyright (c) 2024–present David Oravsky (mrdav30) |
| | | 5 | | // See LICENSE file in the project root for full license information. |
| | | 6 | | //======================================================================= |
| | | 7 | | |
| | | 8 | | using System; |
| | | 9 | | using System.Collections.Generic; |
| | | 10 | | using System.Runtime.CompilerServices; |
| | | 11 | | |
| | | 12 | | namespace SwiftCollections; |
| | | 13 | | |
| | | 14 | | internal static class SwiftArraySortHelper |
| | | 15 | | { |
| | | 16 | | private const int InsertionSortThreshold = 16; |
| | | 17 | | |
| | | 18 | | public static void Sort<T>(T[] array, int index, int length, IComparer<T>? comparer) |
| | | 19 | | { |
| | 56 | 20 | | if (length <= 1) |
| | 0 | 21 | | return; |
| | | 22 | | |
| | 56 | 23 | | if (comparer == null || ReferenceEquals(comparer, Comparer<T>.Default)) |
| | | 24 | | { |
| | 41 | 25 | | Array.Sort(array, index, length); |
| | 41 | 26 | | return; |
| | | 27 | | } |
| | | 28 | | |
| | 15 | 29 | | IntroSort(array, index, index + length - 1, FloorLog2(length) * 2, comparer); |
| | 15 | 30 | | } |
| | | 31 | | |
| | | 32 | | public static void Sort<T, TComparer>(T[] array, int index, int length, TComparer comparer) |
| | | 33 | | where TComparer : struct, IComparer<T> |
| | | 34 | | { |
| | 9 | 35 | | if (length <= 1) |
| | 0 | 36 | | return; |
| | | 37 | | |
| | | 38 | | // Keep the struct-comparer path generic: it avoids boxing and lets the JIT devirtualize hot comparer calls. |
| | 9 | 39 | | IntroSort(array, index, index + length - 1, FloorLog2(length) * 2, comparer); |
| | 9 | 40 | | } |
| | | 41 | | |
| | | 42 | | private static void IntroSort<T>(T[] array, int lo, int hi, int depthLimit, IComparer<T> comparer) |
| | | 43 | | { |
| | 1455 | 44 | | while (hi > lo) |
| | | 45 | | { |
| | 1113 | 46 | | int partitionSize = hi - lo + 1; |
| | 1113 | 47 | | if (partitionSize <= InsertionSortThreshold) |
| | | 48 | | { |
| | 393 | 49 | | InsertionSort(array, lo, hi, comparer); |
| | 393 | 50 | | return; |
| | | 51 | | } |
| | | 52 | | |
| | 720 | 53 | | if (depthLimit == 0) |
| | | 54 | | { |
| | 0 | 55 | | HeapSort(array, lo, hi, comparer); |
| | 0 | 56 | | return; |
| | | 57 | | } |
| | | 58 | | |
| | 720 | 59 | | depthLimit--; |
| | 720 | 60 | | int partition = PickPivotAndPartition(array, lo, hi, comparer); |
| | | 61 | | |
| | 720 | 62 | | if (partition - lo < hi - partition) |
| | | 63 | | { |
| | 492 | 64 | | IntroSort(array, lo, partition - 1, depthLimit, comparer); |
| | 492 | 65 | | lo = partition + 1; |
| | | 66 | | } |
| | | 67 | | else |
| | | 68 | | { |
| | 228 | 69 | | IntroSort(array, partition + 1, hi, depthLimit, comparer); |
| | 228 | 70 | | hi = partition - 1; |
| | | 71 | | } |
| | | 72 | | } |
| | 342 | 73 | | } |
| | | 74 | | |
| | | 75 | | private static int PickPivotAndPartition<T>(T[] array, int lo, int hi, IComparer<T> comparer) |
| | | 76 | | { |
| | 720 | 77 | | int middle = lo + ((hi - lo) >> 1); |
| | | 78 | | |
| | 720 | 79 | | SwapIfGreater(array, comparer, lo, middle); |
| | 720 | 80 | | SwapIfGreater(array, comparer, lo, hi); |
| | 720 | 81 | | SwapIfGreater(array, comparer, middle, hi); |
| | | 82 | | |
| | 720 | 83 | | T pivot = array[middle]; |
| | 720 | 84 | | Swap(array, middle, hi - 1); |
| | | 85 | | |
| | 720 | 86 | | int left = lo; |
| | 720 | 87 | | int right = hi - 1; |
| | | 88 | | |
| | 3402 | 89 | | while (true) |
| | | 90 | | { |
| | 17766 | 91 | | while (comparer.Compare(array[++left], pivot) < 0) |
| | | 92 | | { |
| | | 93 | | } |
| | | 94 | | |
| | 40824 | 95 | | while (comparer.Compare(pivot, array[--right]) < 0) |
| | | 96 | | { |
| | | 97 | | } |
| | | 98 | | |
| | 4122 | 99 | | if (left >= right) |
| | | 100 | | break; |
| | | 101 | | |
| | 3402 | 102 | | Swap(array, left, right); |
| | | 103 | | } |
| | | 104 | | |
| | 720 | 105 | | Swap(array, left, hi - 1); |
| | 720 | 106 | | return left; |
| | | 107 | | } |
| | | 108 | | |
| | | 109 | | private static void HeapSort<T>(T[] array, int lo, int hi, IComparer<T> comparer) |
| | | 110 | | { |
| | 0 | 111 | | int count = hi - lo + 1; |
| | 0 | 112 | | for (int i = count >> 1; i >= 1; i--) |
| | 0 | 113 | | DownHeap(array, i, count, lo, comparer); |
| | | 114 | | |
| | 0 | 115 | | for (int i = count; i > 1; i--) |
| | | 116 | | { |
| | 0 | 117 | | Swap(array, lo, lo + i - 1); |
| | 0 | 118 | | DownHeap(array, 1, i - 1, lo, comparer); |
| | | 119 | | } |
| | 0 | 120 | | } |
| | | 121 | | |
| | | 122 | | private static void DownHeap<T>(T[] array, int index, int count, int lo, IComparer<T> comparer) |
| | | 123 | | { |
| | 0 | 124 | | T value = array[lo + index - 1]; |
| | | 125 | | |
| | 0 | 126 | | while (index <= (count >> 1)) |
| | | 127 | | { |
| | 0 | 128 | | int child = index << 1; |
| | 0 | 129 | | if (child < count && comparer.Compare(array[lo + child - 1], array[lo + child]) < 0) |
| | 0 | 130 | | child++; |
| | | 131 | | |
| | 0 | 132 | | if (comparer.Compare(value, array[lo + child - 1]) >= 0) |
| | | 133 | | break; |
| | | 134 | | |
| | 0 | 135 | | array[lo + index - 1] = array[lo + child - 1]; |
| | 0 | 136 | | index = child; |
| | | 137 | | } |
| | | 138 | | |
| | 0 | 139 | | array[lo + index - 1] = value; |
| | 0 | 140 | | } |
| | | 141 | | |
| | | 142 | | private static void InsertionSort<T>(T[] array, int lo, int hi, IComparer<T> comparer) |
| | | 143 | | { |
| | 10246 | 144 | | for (int i = lo + 1; i <= hi; i++) |
| | | 145 | | { |
| | 4730 | 146 | | T value = array[i]; |
| | 4730 | 147 | | int j = i - 1; |
| | 9472 | 148 | | while (j >= lo && comparer.Compare(value, array[j]) < 0) |
| | | 149 | | { |
| | 4742 | 150 | | array[j + 1] = array[j]; |
| | 4742 | 151 | | j--; |
| | | 152 | | } |
| | | 153 | | |
| | 4730 | 154 | | array[j + 1] = value; |
| | | 155 | | } |
| | 393 | 156 | | } |
| | | 157 | | |
| | | 158 | | [MethodImpl(MethodImplOptions.AggressiveInlining)] |
| | | 159 | | private static void SwapIfGreater<T>(T[] array, IComparer<T> comparer, int left, int right) |
| | | 160 | | { |
| | 2160 | 161 | | if (left != right && comparer.Compare(array[left], array[right]) > 0) |
| | 1038 | 162 | | Swap(array, left, right); |
| | 2160 | 163 | | } |
| | | 164 | | |
| | | 165 | | private static void IntroSort<T, TComparer>(T[] array, int lo, int hi, int depthLimit, TComparer comparer) |
| | | 166 | | where TComparer : struct, IComparer<T> |
| | | 167 | | { |
| | 489 | 168 | | while (hi > lo) |
| | | 169 | | { |
| | 375 | 170 | | int partitionSize = hi - lo + 1; |
| | 375 | 171 | | if (partitionSize <= InsertionSortThreshold) |
| | | 172 | | { |
| | 135 | 173 | | InsertionSort(array, lo, hi, comparer); |
| | 135 | 174 | | return; |
| | | 175 | | } |
| | | 176 | | |
| | 240 | 177 | | if (depthLimit == 0) |
| | | 178 | | { |
| | 0 | 179 | | HeapSort(array, lo, hi, comparer); |
| | 0 | 180 | | return; |
| | | 181 | | } |
| | | 182 | | |
| | 240 | 183 | | depthLimit--; |
| | 240 | 184 | | int partition = PickPivotAndPartition(array, lo, hi, comparer); |
| | | 185 | | |
| | 240 | 186 | | if (partition - lo < hi - partition) |
| | | 187 | | { |
| | 164 | 188 | | IntroSort(array, lo, partition - 1, depthLimit, comparer); |
| | 164 | 189 | | lo = partition + 1; |
| | | 190 | | } |
| | | 191 | | else |
| | | 192 | | { |
| | 76 | 193 | | IntroSort(array, partition + 1, hi, depthLimit, comparer); |
| | 76 | 194 | | hi = partition - 1; |
| | | 195 | | } |
| | | 196 | | } |
| | 114 | 197 | | } |
| | | 198 | | |
| | | 199 | | private static int PickPivotAndPartition<T, TComparer>(T[] array, int lo, int hi, TComparer comparer) |
| | | 200 | | where TComparer : struct, IComparer<T> |
| | | 201 | | { |
| | 240 | 202 | | int middle = lo + ((hi - lo) >> 1); |
| | | 203 | | |
| | 240 | 204 | | SwapIfGreater(array, comparer, lo, middle); |
| | 240 | 205 | | SwapIfGreater(array, comparer, lo, hi); |
| | 240 | 206 | | SwapIfGreater(array, comparer, middle, hi); |
| | | 207 | | |
| | 240 | 208 | | T pivot = array[middle]; |
| | 240 | 209 | | Swap(array, middle, hi - 1); |
| | | 210 | | |
| | 240 | 211 | | int left = lo; |
| | 240 | 212 | | int right = hi - 1; |
| | | 213 | | |
| | 1134 | 214 | | while (true) |
| | | 215 | | { |
| | 5922 | 216 | | while (comparer.Compare(array[++left], pivot) < 0) |
| | | 217 | | { |
| | | 218 | | } |
| | | 219 | | |
| | 13608 | 220 | | while (comparer.Compare(pivot, array[--right]) < 0) |
| | | 221 | | { |
| | | 222 | | } |
| | | 223 | | |
| | 1374 | 224 | | if (left >= right) |
| | | 225 | | break; |
| | | 226 | | |
| | 1134 | 227 | | Swap(array, left, right); |
| | | 228 | | } |
| | | 229 | | |
| | 240 | 230 | | Swap(array, left, hi - 1); |
| | 240 | 231 | | return left; |
| | | 232 | | } |
| | | 233 | | |
| | | 234 | | private static void HeapSort<T, TComparer>(T[] array, int lo, int hi, TComparer comparer) |
| | | 235 | | where TComparer : struct, IComparer<T> |
| | | 236 | | { |
| | 0 | 237 | | int count = hi - lo + 1; |
| | 0 | 238 | | for (int i = count >> 1; i >= 1; i--) |
| | 0 | 239 | | DownHeap(array, i, count, lo, comparer); |
| | | 240 | | |
| | 0 | 241 | | for (int i = count; i > 1; i--) |
| | | 242 | | { |
| | 0 | 243 | | Swap(array, lo, lo + i - 1); |
| | 0 | 244 | | DownHeap(array, 1, i - 1, lo, comparer); |
| | | 245 | | } |
| | 0 | 246 | | } |
| | | 247 | | |
| | | 248 | | private static void DownHeap<T, TComparer>(T[] array, int index, int count, int lo, TComparer comparer) |
| | | 249 | | where TComparer : struct, IComparer<T> |
| | | 250 | | { |
| | 0 | 251 | | T value = array[lo + index - 1]; |
| | | 252 | | |
| | 0 | 253 | | while (index <= (count >> 1)) |
| | | 254 | | { |
| | 0 | 255 | | int child = index << 1; |
| | 0 | 256 | | if (child < count && comparer.Compare(array[lo + child - 1], array[lo + child]) < 0) |
| | 0 | 257 | | child++; |
| | | 258 | | |
| | 0 | 259 | | if (comparer.Compare(value, array[lo + child - 1]) >= 0) |
| | | 260 | | break; |
| | | 261 | | |
| | 0 | 262 | | array[lo + index - 1] = array[lo + child - 1]; |
| | 0 | 263 | | index = child; |
| | | 264 | | } |
| | | 265 | | |
| | 0 | 266 | | array[lo + index - 1] = value; |
| | 0 | 267 | | } |
| | | 268 | | |
| | | 269 | | private static void InsertionSort<T, TComparer>(T[] array, int lo, int hi, TComparer comparer) |
| | | 270 | | where TComparer : struct, IComparer<T> |
| | | 271 | | { |
| | 3440 | 272 | | for (int i = lo + 1; i <= hi; i++) |
| | | 273 | | { |
| | 1585 | 274 | | T value = array[i]; |
| | 1585 | 275 | | int j = i - 1; |
| | 3178 | 276 | | while (j >= lo && comparer.Compare(value, array[j]) < 0) |
| | | 277 | | { |
| | 1593 | 278 | | array[j + 1] = array[j]; |
| | 1593 | 279 | | j--; |
| | | 280 | | } |
| | | 281 | | |
| | 1585 | 282 | | array[j + 1] = value; |
| | | 283 | | } |
| | 135 | 284 | | } |
| | | 285 | | |
| | | 286 | | [MethodImpl(MethodImplOptions.AggressiveInlining)] |
| | | 287 | | private static void SwapIfGreater<T, TComparer>(T[] array, TComparer comparer, int left, int right) |
| | | 288 | | where TComparer : struct, IComparer<T> |
| | | 289 | | { |
| | 720 | 290 | | if (left != right && comparer.Compare(array[left], array[right]) > 0) |
| | 346 | 291 | | Swap(array, left, right); |
| | 720 | 292 | | } |
| | | 293 | | |
| | | 294 | | [MethodImpl(MethodImplOptions.AggressiveInlining)] |
| | | 295 | | private static void Swap<T>(T[] array, int left, int right) |
| | | 296 | | { |
| | 7840 | 297 | | if (left == right) |
| | 0 | 298 | | return; |
| | | 299 | | |
| | 7840 | 300 | | T value = array[left]; |
| | 7840 | 301 | | array[left] = array[right]; |
| | 7840 | 302 | | array[right] = value; |
| | 7840 | 303 | | } |
| | | 304 | | |
| | | 305 | | private static int FloorLog2(int value) |
| | | 306 | | { |
| | 24 | 307 | | int result = 0; |
| | 130 | 308 | | while (value >= 2) |
| | | 309 | | { |
| | 106 | 310 | | result++; |
| | 106 | 311 | | value >>= 1; |
| | | 312 | | } |
| | | 313 | | |
| | 24 | 314 | | return result; |
| | | 315 | | } |
| | | 316 | | } |
| | | 317 | | |
| | | 318 | | internal readonly struct SwiftIntAscendingComparer : IComparer<int> |
| | | 319 | | { |
| | | 320 | | [MethodImpl(MethodImplOptions.AggressiveInlining)] |
| | | 321 | | public int Compare(int x, int y) |
| | | 322 | | { |
| | | 323 | | return x.CompareTo(y); |
| | | 324 | | } |
| | | 325 | | } |