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| 1 | // SPDX-License-Identifier: MIT |
| 2 | // Copyright (c) 2021 Zig Contributors |
| 3 | // This file is part of [zig](https://ziglang.org/), which is MIT licensed. |
| 4 | // The MIT license requires this copyright notice to be included in all copies |
| 5 | // and substantial portions of the software. |
| 6 | |
| 7 | const std = @import("std"); |
| 8 | const assert = std.debug.assert; |
| 9 | const Allocator = std.mem.Allocator; |
| 10 | |
| 11 | //! This file defines several variants of bit sets. A bit set |
| 12 | //! is a densely stored set of integers with a known maximum, |
| 13 | //! in which each integer gets a single bit. Bit sets have very |
| 14 | //! fast presence checks, update operations, and union and intersection |
| 15 | //! operations. However, if the number of possible items is very |
| 16 | //! large and the number of actual items in a given set is usually |
| 17 | //! small, they may be less memory efficient than an array set. |
| 18 | //! |
| 19 | //! There are five variants defined here: |
| 20 | //! |
| 21 | //! IntegerBitSet: |
| 22 | //! A bit set with static size, which is backed by a single integer. |
| 23 | //! This set is good for sets with a small size, but may generate |
| 24 | //! inefficient code for larger sets, especially in debug mode. |
| 25 | //! |
| 26 | //! ArrayBitSet: |
| 27 | //! A bit set with static size, which is backed by an array of usize. |
| 28 | //! This set is good for sets with a larger size, but may use |
| 29 | //! more bytes than necessary if your set is small. |
| 30 | //! |
| 31 | //! StaticBitSet: |
| 32 | //! Picks either IntegerBitSet or ArrayBitSet depending on the requested |
| 33 | //! size. The interfaces of these two types match exactly, except for fields. |
| 34 | //! |
| 35 | //! DynamicBitSet: |
| 36 | //! A bit set with runtime known size, backed by an allocated slice |
| 37 | //! of usize. |
| 38 | //! |
| 39 | //! DynamicBitSetUnmanaged: |
| 40 | //! A variant of DynamicBitSet which does not store a pointer to its |
| 41 | //! allocator, in order to save space. |
| 42 | |
| 43 | /// Returns the optimal static bit set type for the specified number |
| 44 | /// of elements. The returned type will perform no allocations, |
| 45 | /// can be copied by value, and does not require deinitialization. |
| 46 | /// Both possible implementations fulfill the same interface. |
| 47 | pub fn StaticBitSet(comptime size: usize) type { |
| 48 | if (size <= @bitSizeOf(usize)) { |
| 49 | return IntegerBitSet(size); |
| 50 | } else { |
| 51 | return ArrayBitSet(usize, size); |
| 52 | } |
| 53 | } |
| 54 | |
| 55 | /// A bit set with static size, which is backed by a single integer. |
| 56 | /// This set is good for sets with a small size, but may generate |
| 57 | /// inefficient code for larger sets, especially in debug mode. |
| 58 | pub fn IntegerBitSet(comptime size: u16) type { |
| 59 | return struct { |
| 60 | const Self = @This(); |
| 61 | |
| 62 | // TODO: Make this a comptime field once those are fixed |
| 63 | /// The number of items in this bit set |
| 64 | pub const bit_length: usize = size; |
| 65 | |
| 66 | /// The integer type used to represent a mask in this bit set |
| 67 | pub const MaskInt = std.meta.Int(.unsigned, size); |
| 68 | |
| 69 | /// The integer type used to shift a mask in this bit set |
| 70 | pub const ShiftInt = std.math.Log2Int(MaskInt); |
| 71 | |
| 72 | /// The bit mask, as a single integer |
| 73 | mask: MaskInt, |
| 74 | |
| 75 | /// Creates a bit set with no elements present. |
| 76 | pub fn initEmpty() Self { |
| 77 | return .{ .mask = 0 }; |
| 78 | } |
| 79 | |
| 80 | /// Creates a bit set with all elements present. |
| 81 | pub fn initFull() Self { |
| 82 | return .{ .mask = ~@as(MaskInt, 0) }; |
| 83 | } |
| 84 | |
| 85 | /// Returns the number of bits in this bit set |
| 86 | pub inline fn capacity(self: Self) usize { |
| 87 | return bit_length; |
| 88 | } |
| 89 | |
| 90 | /// Returns true if the bit at the specified index |
| 91 | /// is present in the set, false otherwise. |
| 92 | pub fn isSet(self: Self, index: usize) bool { |
| 93 | assert(index < bit_length); |
| 94 | return (self.mask & maskBit(index)) != 0; |
| 95 | } |
| 96 | |
| 97 | /// Returns the total number of set bits in this bit set. |
| 98 | pub fn count(self: Self) usize { |
| 99 | return @popCount(MaskInt, self.mask); |
| 100 | } |
| 101 | |
| 102 | /// Changes the value of the specified bit of the bit |
| 103 | /// set to match the passed boolean. |
| 104 | pub fn setValue(self: *Self, index: usize, value: bool) void { |
| 105 | assert(index < bit_length); |
| 106 | if (MaskInt == u0) return; |
| 107 | const bit = maskBit(index); |
| 108 | const new_bit = bit & std.math.boolMask(MaskInt, value); |
| 109 | self.mask = (self.mask & ~bit) | new_bit; |
| 110 | } |
| 111 | |
| 112 | /// Adds a specific bit to the bit set |
| 113 | pub fn set(self: *Self, index: usize) void { |
| 114 | assert(index < bit_length); |
| 115 | self.mask |= maskBit(index); |
| 116 | } |
| 117 | |
| 118 | /// Removes a specific bit from the bit set |
| 119 | pub fn unset(self: *Self, index: usize) void { |
| 120 | assert(index < bit_length); |
| 121 | // Workaround for #7953 |
| 122 | if (MaskInt == u0) return; |
| 123 | self.mask &= ~maskBit(index); |
| 124 | } |
| 125 | |
| 126 | /// Flips a specific bit in the bit set |
| 127 | pub fn toggle(self: *Self, index: usize) void { |
| 128 | assert(index < bit_length); |
| 129 | self.mask ^= maskBit(index); |
| 130 | } |
| 131 | |
| 132 | /// Flips all bits in this bit set which are present |
| 133 | /// in the toggles bit set. |
| 134 | pub fn toggleSet(self: *Self, toggles: Self) void { |
| 135 | self.mask ^= toggles.mask; |
| 136 | } |
| 137 | |
| 138 | /// Flips every bit in the bit set. |
| 139 | pub fn toggleAll(self: *Self) void { |
| 140 | self.mask = ~self.mask; |
| 141 | } |
| 142 | |
| 143 | /// Performs a union of two bit sets, and stores the |
| 144 | /// result in the first one. Bits in the result are |
| 145 | /// set if the corresponding bits were set in either input. |
| 146 | pub fn setUnion(self: *Self, other: Self) void { |
| 147 | self.mask |= other.mask; |
| 148 | } |
| 149 | |
| 150 | /// Performs an intersection of two bit sets, and stores |
| 151 | /// the result in the first one. Bits in the result are |
| 152 | /// set if the corresponding bits were set in both inputs. |
| 153 | pub fn setIntersection(self: *Self, other: Self) void { |
| 154 | self.mask &= other.mask; |
| 155 | } |
| 156 | |
| 157 | /// Finds the index of the first set bit. |
| 158 | /// If no bits are set, returns null. |
| 159 | pub fn findFirstSet(self: Self) ?usize { |
| 160 | const mask = self.mask; |
| 161 | if (mask == 0) return null; |
| 162 | return @ctz(MaskInt, mask); |
| 163 | } |
| 164 | |
| 165 | /// Finds the index of the first set bit, and unsets it. |
| 166 | /// If no bits are set, returns null. |
| 167 | pub fn toggleFirstSet(self: *Self) ?usize { |
| 168 | const mask = self.mask; |
| 169 | if (mask == 0) return null; |
| 170 | const index = @ctz(MaskInt, mask); |
| 171 | self.mask = mask & (mask-1); |
| 172 | return index; |
| 173 | } |
| 174 | |
| 175 | /// Iterates through the items in the set, according to the options. |
| 176 | /// The default options (.{}) will iterate indices of set bits in |
| 177 | /// ascending order. Modifications to the underlying bit set may |
| 178 | /// or may not be observed by the iterator. |
| 179 | pub fn iterator(self: *const Self, comptime options: IteratorOptions) Iterator(options.direction) { |
| 180 | return .{ |
| 181 | .bits_remain = switch (options.kind) { |
| 182 | .set => self.mask, |
| 183 | .unset => ~self.mask, |
| 184 | }, |
| 185 | }; |
| 186 | } |
| 187 | |
| 188 | fn Iterator(comptime direction: IteratorOptions.Direction) type { |
| 189 | return struct { |
| 190 | const IterSelf = @This(); |
| 191 | // all bits which have not yet been iterated over |
| 192 | bits_remain: MaskInt, |
| 193 | |
| 194 | /// Returns the index of the next unvisited set bit |
| 195 | /// in the bit set, in ascending order. |
| 196 | pub fn next(self: *IterSelf) ?usize { |
| 197 | if (self.bits_remain == 0) return null; |
| 198 | |
| 199 | switch (direction) { |
| 200 | .forward => { |
| 201 | const next_index = @ctz(MaskInt, self.bits_remain); |
| 202 | self.bits_remain &= self.bits_remain - 1; |
| 203 | return next_index; |
| 204 | }, |
| 205 | .reverse => { |
| 206 | const leading_zeroes = @clz(MaskInt, self.bits_remain); |
| 207 | const top_bit = (@bitSizeOf(MaskInt) - 1) - leading_zeroes; |
| 208 | self.bits_remain &= (@as(MaskInt, 1) << @intCast(ShiftInt, top_bit)) - 1; |
| 209 | return top_bit; |
| 210 | }, |
| 211 | } |
| 212 | } |
| 213 | }; |
| 214 | } |
| 215 | |
| 216 | fn maskBit(index: usize) MaskInt { |
| 217 | if (MaskInt == u0) return 0; |
| 218 | return @as(MaskInt, 1) << @intCast(ShiftInt, index); |
| 219 | } |
| 220 | fn boolMaskBit(index: usize, value: bool) MaskInt { |
| 221 | if (MaskInt == u0) return 0; |
| 222 | return @as(MaskInt, @boolToInt(value)) << @intCast(ShiftInt, index); |
| 223 | } |
| 224 | }; |
| 225 | } |
| 226 | |
| 227 | /// A bit set with static size, which is backed by an array of usize. |
| 228 | /// This set is good for sets with a larger size, but may use |
| 229 | /// more bytes than necessary if your set is small. |
| 230 | pub fn ArrayBitSet(comptime MaskIntType: type, comptime size: usize) type { |
| 231 | const mask_info: std.builtin.TypeInfo = @typeInfo(MaskIntType); |
| 232 | |
| 233 | // Make sure the mask int is indeed an int |
| 234 | if (mask_info != .Int) @compileError("ArrayBitSet can only operate on integer masks, but was passed " ++ @typeName(MaskIntType)); |
| 235 | |
| 236 | // It must also be unsigned. |
| 237 | if (mask_info.Int.signedness != .unsigned) @compileError("ArrayBitSet requires an unsigned integer mask type, but was passed " ++ @typeName(MaskIntType)); |
| 238 | |
| 239 | // And it must not be empty. |
| 240 | if (MaskIntType == u0) |
| 241 | @compileError("ArrayBitSet requires a sized integer for its mask int. u0 does not work."); |
| 242 | |
| 243 | const byte_size = std.mem.byte_size_in_bits; |
| 244 | |
| 245 | // We use shift and truncate to decompose indices into mask indices and bit indices. |
| 246 | // This operation requires that the mask has an exact power of two number of bits. |
| 247 | if (!std.math.isPowerOfTwo(@bitSizeOf(MaskIntType))) { |
| 248 | var desired_bits = std.math.ceilPowerOfTwoAssert(usize, @bitSizeOf(MaskIntType)); |
| 249 | if (desired_bits < byte_size) desired_bits = byte_size; |
| 250 | const FixedMaskType = std.meta.Int(.unsigned, desired_bits); |
| 251 | @compileError("ArrayBitSet was passed integer type " ++ @typeName(MaskIntType) ++ |
| 252 | ", which is not a power of two. Please round this up to a power of two integer size (i.e. " ++ @typeName(FixedMaskType) ++ ")."); |
| 253 | } |
| 254 | |
| 255 | // Make sure the integer has no padding bits. |
| 256 | // Those would be wasteful here and are probably a mistake by the user. |
| 257 | // This case may be hit with small powers of two, like u4. |
| 258 | if (@bitSizeOf(MaskIntType) != @sizeOf(MaskIntType) * byte_size) { |
| 259 | var desired_bits = @sizeOf(MaskIntType) * byte_size; |
| 260 | desired_bits = std.math.ceilPowerOfTwoAssert(usize, desired_bits); |
| 261 | const FixedMaskType = std.meta.Int(.unsigned, desired_bits); |
| 262 | @compileError("ArrayBitSet was passed integer type " ++ @typeName(MaskIntType) ++ |
| 263 | ", which contains padding bits. Please round this up to an unpadded integer size (i.e. " ++ @typeName(FixedMaskType) ++ ")."); |
| 264 | } |
| 265 | |
| 266 | return struct { |
| 267 | const Self = @This(); |
| 268 | |
| 269 | // TODO: Make this a comptime field once those are fixed |
| 270 | /// The number of items in this bit set |
| 271 | pub const bit_length: usize = size; |
| 272 | |
| 273 | /// The integer type used to represent a mask in this bit set |
| 274 | pub const MaskInt = MaskIntType; |
| 275 | |
| 276 | /// The integer type used to shift a mask in this bit set |
| 277 | pub const ShiftInt = std.math.Log2Int(MaskInt); |
| 278 | |
| 279 | // bits in one mask |
| 280 | const mask_len = @bitSizeOf(MaskInt); |
| 281 | // total number of masks |
| 282 | const num_masks = (size + mask_len - 1) / mask_len; |
| 283 | // padding bits in the last mask (may be 0) |
| 284 | const last_pad_bits = mask_len * num_masks - size; |
| 285 | // Mask of valid bits in the last mask. |
| 286 | // All functions will ensure that the invalid |
| 287 | // bits in the last mask are zero. |
| 288 | pub const last_item_mask = ~@as(MaskInt, 0) >> last_pad_bits; |
| 289 | |
| 290 | /// The bit masks, ordered with lower indices first. |
| 291 | /// Padding bits at the end are undefined. |
| 292 | masks: [num_masks]MaskInt, |
| 293 | |
| 294 | /// Creates a bit set with no elements present. |
| 295 | pub fn initEmpty() Self { |
| 296 | return .{ .masks = [_]MaskInt{0} ** num_masks }; |
| 297 | } |
| 298 | |
| 299 | /// Creates a bit set with all elements present. |
| 300 | pub fn initFull() Self { |
| 301 | if (num_masks == 0) { |
| 302 | return .{ .masks = .{} }; |
| 303 | } else { |
| 304 | return .{ .masks = [_]MaskInt{~@as(MaskInt, 0)} ** (num_masks - 1) ++ [_]MaskInt{last_item_mask} }; |
| 305 | } |
| 306 | } |
| 307 | |
| 308 | /// Returns the number of bits in this bit set |
| 309 | pub inline fn capacity(self: Self) usize { |
| 310 | return bit_length; |
| 311 | } |
| 312 | |
| 313 | /// Returns true if the bit at the specified index |
| 314 | /// is present in the set, false otherwise. |
| 315 | pub fn isSet(self: Self, index: usize) bool { |
| 316 | assert(index < bit_length); |
| 317 | if (num_masks == 0) return false; // doesn't compile in this case |
| 318 | return (self.masks[maskIndex(index)] & maskBit(index)) != 0; |
| 319 | } |
| 320 | |
| 321 | /// Returns the total number of set bits in this bit set. |
| 322 | pub fn count(self: Self) usize { |
| 323 | var total: usize = 0; |
| 324 | for (self.masks) |mask| { |
| 325 | total += @popCount(MaskInt, mask); |
| 326 | } |
| 327 | return total; |
| 328 | } |
| 329 | |
| 330 | /// Changes the value of the specified bit of the bit |
| 331 | /// set to match the passed boolean. |
| 332 | pub fn setValue(self: *Self, index: usize, value: bool) void { |
| 333 | assert(index < bit_length); |
| 334 | if (num_masks == 0) return; // doesn't compile in this case |
| 335 | const bit = maskBit(index); |
| 336 | const mask_index = maskIndex(index); |
| 337 | const new_bit = bit & std.math.boolMask(MaskInt, value); |
| 338 | self.masks[mask_index] = (self.masks[mask_index] & ~bit) | new_bit; |
| 339 | } |
| 340 | |
| 341 | /// Adds a specific bit to the bit set |
| 342 | pub fn set(self: *Self, index: usize) void { |
| 343 | assert(index < bit_length); |
| 344 | if (num_masks == 0) return; // doesn't compile in this case |
| 345 | self.masks[maskIndex(index)] |= maskBit(index); |
| 346 | } |
| 347 | |
| 348 | /// Removes a specific bit from the bit set |
| 349 | pub fn unset(self: *Self, index: usize) void { |
| 350 | assert(index < bit_length); |
| 351 | if (num_masks == 0) return; // doesn't compile in this case |
| 352 | self.masks[maskIndex(index)] &= ~maskBit(index); |
| 353 | } |
| 354 | |
| 355 | /// Flips a specific bit in the bit set |
| 356 | pub fn toggle(self: *Self, index: usize) void { |
| 357 | assert(index < bit_length); |
| 358 | if (num_masks == 0) return; // doesn't compile in this case |
| 359 | self.masks[maskIndex(index)] ^= maskBit(index); |
| 360 | } |
| 361 | |
| 362 | /// Flips all bits in this bit set which are present |
| 363 | /// in the toggles bit set. |
| 364 | pub fn toggleSet(self: *Self, toggles: Self) void { |
| 365 | for (self.masks) |*mask, i| { |
| 366 | mask.* ^= toggles.masks[i]; |
| 367 | } |
| 368 | } |
| 369 | |
| 370 | /// Flips every bit in the bit set. |
| 371 | pub fn toggleAll(self: *Self) void { |
| 372 | for (self.masks) |*mask, i| { |
| 373 | mask.* = ~mask.*; |
| 374 | } |
| 375 | |
| 376 | // Zero the padding bits |
| 377 | if (num_masks > 0) { |
| 378 | self.masks[num_masks - 1] &= last_item_mask; |
| 379 | } |
| 380 | } |
| 381 | |
| 382 | /// Performs a union of two bit sets, and stores the |
| 383 | /// result in the first one. Bits in the result are |
| 384 | /// set if the corresponding bits were set in either input. |
| 385 | pub fn setUnion(self: *Self, other: Self) void { |
| 386 | for (self.masks) |*mask, i| { |
| 387 | mask.* |= other.masks[i]; |
| 388 | } |
| 389 | } |
| 390 | |
| 391 | /// Performs an intersection of two bit sets, and stores |
| 392 | /// the result in the first one. Bits in the result are |
| 393 | /// set if the corresponding bits were set in both inputs. |
| 394 | pub fn setIntersection(self: *Self, other: Self) void { |
| 395 | for (self.masks) |*mask, i| { |
| 396 | mask.* &= other.masks[i]; |
| 397 | } |
| 398 | } |
| 399 | |
| 400 | /// Finds the index of the first set bit. |
| 401 | /// If no bits are set, returns null. |
| 402 | pub fn findFirstSet(self: Self) ?usize { |
| 403 | var offset: usize = 0; |
| 404 | const mask = for (self.masks) |mask| { |
| 405 | if (mask != 0) break mask; |
| 406 | offset += @bitSizeOf(MaskInt); |
| 407 | } else return null; |
| 408 | return offset + @ctz(MaskInt, mask); |
| 409 | } |
| 410 | |
| 411 | /// Finds the index of the first set bit, and unsets it. |
| 412 | /// If no bits are set, returns null. |
| 413 | pub fn toggleFirstSet(self: *Self) ?usize { |
| 414 | var offset: usize = 0; |
| 415 | const mask = for (self.masks) |*mask| { |
| 416 | if (mask.* != 0) break mask; |
| 417 | offset += @bitSizeOf(MaskInt); |
| 418 | } else return null; |
| 419 | const index = @ctz(MaskInt, mask.*); |
| 420 | mask.* &= (mask.* - 1); |
| 421 | return offset + index; |
| 422 | } |
| 423 | |
| 424 | /// Iterates through the items in the set, according to the options. |
| 425 | /// The default options (.{}) will iterate indices of set bits in |
| 426 | /// ascending order. Modifications to the underlying bit set may |
| 427 | /// or may not be observed by the iterator. |
| 428 | pub fn iterator(self: *const Self, comptime options: IteratorOptions) BitSetIterator(MaskInt, options) { |
| 429 | return BitSetIterator(MaskInt, options).init(&self.masks, last_item_mask); |
| 430 | } |
| 431 | |
| 432 | fn maskBit(index: usize) MaskInt { |
| 433 | return @as(MaskInt, 1) << @truncate(ShiftInt, index); |
| 434 | } |
| 435 | fn maskIndex(index: usize) usize { |
| 436 | return index >> @bitSizeOf(ShiftInt); |
| 437 | } |
| 438 | fn boolMaskBit(index: usize, value: bool) MaskInt { |
| 439 | return @as(MaskInt, @boolToInt(value)) << @intCast(ShiftInt, index); |
| 440 | } |
| 441 | }; |
| 442 | } |
| 443 | |
| 444 | /// A bit set with runtime known size, backed by an allocated slice |
| 445 | /// of usize. The allocator must be tracked externally by the user. |
| 446 | pub const DynamicBitSetUnmanaged = struct { |
| 447 | const Self = @This(); |
| 448 | |
| 449 | /// The integer type used to represent a mask in this bit set |
| 450 | pub const MaskInt = usize; |
| 451 | |
| 452 | /// The integer type used to shift a mask in this bit set |
| 453 | pub const ShiftInt = std.math.Log2Int(MaskInt); |
| 454 | |
| 455 | /// The number of valid items in this bit set |
| 456 | bit_length: usize = 0, |
| 457 | |
| 458 | /// The bit masks, ordered with lower indices first. |
| 459 | /// Padding bits at the end must be zeroed. |
| 460 | masks: [*]MaskInt = empty_masks_ptr, |
| 461 | // This pointer is one usize after the actual allocation. |
| 462 | // That slot holds the size of the true allocation, which |
| 463 | // is needed by Zig's allocator interface in case a shrink |
| 464 | // fails. |
| 465 | |
| 466 | // Don't modify this value. Ideally it would go in const data so |
| 467 | // modifications would cause a bus error, but the only way |
| 468 | // to discard a const qualifier is through ptrToInt, which |
| 469 | // cannot currently round trip at comptime. |
| 470 | var empty_masks_data = [_]MaskInt{ 0, undefined }; |
| 471 | const empty_masks_ptr = empty_masks_data[1..2]; |
| 472 | |
| 473 | /// Creates a bit set with no elements present. |
| 474 | /// If bit_length is not zero, deinit must eventually be called. |
| 475 | pub fn initEmpty(bit_length: usize, allocator: *Allocator) !Self { |
| 476 | var self = Self{}; |
| 477 | try self.resize(bit_length, false, allocator); |
| 478 | return self; |
| 479 | } |
| 480 | |
| 481 | /// Creates a bit set with all elements present. |
| 482 | /// If bit_length is not zero, deinit must eventually be called. |
| 483 | pub fn initFull(bit_length: usize, allocator: *Allocator) !Self { |
| 484 | var self = Self{}; |
| 485 | try self.resize(bit_length, true, allocator); |
| 486 | return self; |
| 487 | } |
| 488 | |
| 489 | /// Resizes to a new bit_length. If the new length is larger |
| 490 | /// than the old length, fills any added bits with `fill`. |
| 491 | /// If new_len is not zero, deinit must eventually be called. |
| 492 | pub fn resize(self: *@This(), new_len: usize, fill: bool, allocator: *Allocator) !void { |
| 493 | const old_len = self.bit_length; |
| 494 | |
| 495 | const old_masks = numMasks(old_len); |
| 496 | const new_masks = numMasks(new_len); |
| 497 | |
| 498 | const old_allocation = (self.masks - 1)[0..(self.masks - 1)[0]]; |
| 499 | |
| 500 | if (new_masks == 0) { |
| 501 | assert(new_len == 0); |
| 502 | allocator.free(old_allocation); |
| 503 | self.masks = empty_masks_ptr; |
| 504 | self.bit_length = 0; |
| 505 | return; |
| 506 | } |
| 507 | |
| 508 | if (old_allocation.len != new_masks + 1) realloc: { |
| 509 | // If realloc fails, it may mean one of two things. |
| 510 | // If we are growing, it means we are out of memory. |
| 511 | // If we are shrinking, it means the allocator doesn't |
| 512 | // want to move the allocation. This means we need to |
| 513 | // hold on to the extra 8 bytes required to be able to free |
| 514 | // this allocation properly. |
| 515 | const new_allocation = allocator.realloc(old_allocation, new_masks + 1) catch |err| { |
| 516 | if (new_masks + 1 > old_allocation.len) return err; |
| 517 | break :realloc; |
| 518 | }; |
| 519 | |
| 520 | new_allocation[0] = new_allocation.len; |
| 521 | self.masks = new_allocation.ptr + 1; |
| 522 | } |
| 523 | |
| 524 | // If we increased in size, we need to set any new bits |
| 525 | // to the fill value. |
| 526 | if (new_len > old_len) { |
| 527 | // set the padding bits in the old last item to 1 |
| 528 | if (fill and old_masks > 0) { |
| 529 | const old_padding_bits = old_masks * @bitSizeOf(MaskInt) - old_len; |
| 530 | const old_mask = (~@as(MaskInt, 0)) >> @intCast(ShiftInt, old_padding_bits); |
| 531 | self.masks[old_masks - 1] |= ~old_mask; |
| 532 | } |
| 533 | |
| 534 | // fill in any new masks |
| 535 | if (new_masks > old_masks) { |
| 536 | const fill_value = std.math.boolMask(MaskInt, fill); |
| 537 | std.mem.set(MaskInt, self.masks[old_masks..new_masks], fill_value); |
| 538 | } |
| 539 | } |
| 540 | |
| 541 | // Zero out the padding bits |
| 542 | if (new_len > 0) { |
| 543 | const padding_bits = new_masks * @bitSizeOf(MaskInt) - new_len; |
| 544 | const last_item_mask = (~@as(MaskInt, 0)) >> @intCast(ShiftInt, padding_bits); |
| 545 | self.masks[new_masks - 1] &= last_item_mask; |
| 546 | } |
| 547 | |
| 548 | // And finally, save the new length. |
| 549 | self.bit_length = new_len; |
| 550 | } |
| 551 | |
| 552 | /// deinitializes the array and releases its memory. |
| 553 | /// The passed allocator must be the same one used for |
| 554 | /// init* or resize in the past. |
| 555 | pub fn deinit(self: *Self, allocator: *Allocator) void { |
| 556 | self.resize(0, false, allocator) catch unreachable; |
| 557 | } |
| 558 | |
| 559 | /// Creates a duplicate of this bit set, using the new allocator. |
| 560 | pub fn clone(self: *const Self, new_allocator: *Allocator) !Self { |
| 561 | const num_masks = numMasks(self.bit_length); |
| 562 | var copy = Self{}; |
| 563 | try copy.resize(self.bit_length, false, new_allocator); |
| 564 | std.mem.copy(MaskInt, copy.masks[0..num_masks], self.masks[0..num_masks]); |
| 565 | return copy; |
| 566 | } |
| 567 | |
| 568 | /// Returns the number of bits in this bit set |
| 569 | pub inline fn capacity(self: Self) usize { |
| 570 | return self.bit_length; |
| 571 | } |
| 572 | |
| 573 | /// Returns true if the bit at the specified index |
| 574 | /// is present in the set, false otherwise. |
| 575 | pub fn isSet(self: Self, index: usize) bool { |
| 576 | assert(index < self.bit_length); |
| 577 | return (self.masks[maskIndex(index)] & maskBit(index)) != 0; |
| 578 | } |
| 579 | |
| 580 | /// Returns the total number of set bits in this bit set. |
| 581 | pub fn count(self: Self) usize { |
| 582 | const num_masks = (self.bit_length + (@bitSizeOf(MaskInt) - 1)) / @bitSizeOf(MaskInt); |
| 583 | var total: usize = 0; |
| 584 | for (self.masks[0..num_masks]) |mask| { |
| 585 | // Note: This is where we depend on padding bits being zero |
| 586 | total += @popCount(MaskInt, mask); |
| 587 | } |
| 588 | return total; |
| 589 | } |
| 590 | |
| 591 | /// Changes the value of the specified bit of the bit |
| 592 | /// set to match the passed boolean. |
| 593 | pub fn setValue(self: *Self, index: usize, value: bool) void { |
| 594 | assert(index < self.bit_length); |
| 595 | const bit = maskBit(index); |
| 596 | const mask_index = maskIndex(index); |
| 597 | const new_bit = bit & std.math.boolMask(MaskInt, value); |
| 598 | self.masks[mask_index] = (self.masks[mask_index] & ~bit) | new_bit; |
| 599 | } |
| 600 | |
| 601 | /// Adds a specific bit to the bit set |
| 602 | pub fn set(self: *Self, index: usize) void { |
| 603 | assert(index < self.bit_length); |
| 604 | self.masks[maskIndex(index)] |= maskBit(index); |
| 605 | } |
| 606 | |
| 607 | /// Removes a specific bit from the bit set |
| 608 | pub fn unset(self: *Self, index: usize) void { |
| 609 | assert(index < self.bit_length); |
| 610 | self.masks[maskIndex(index)] &= ~maskBit(index); |
| 611 | } |
| 612 | |
| 613 | /// Flips a specific bit in the bit set |
| 614 | pub fn toggle(self: *Self, index: usize) void { |
| 615 | assert(index < self.bit_length); |
| 616 | self.masks[maskIndex(index)] ^= maskBit(index); |
| 617 | } |
| 618 | |
| 619 | /// Flips all bits in this bit set which are present |
| 620 | /// in the toggles bit set. Both sets must have the |
| 621 | /// same bit_length. |
| 622 | pub fn toggleSet(self: *Self, toggles: Self) void { |
| 623 | assert(toggles.bit_length == self.bit_length); |
| 624 | const num_masks = numMasks(self.bit_length); |
| 625 | for (self.masks[0..num_masks]) |*mask, i| { |
| 626 | mask.* ^= toggles.masks[i]; |
| 627 | } |
| 628 | } |
| 629 | |
| 630 | /// Flips every bit in the bit set. |
| 631 | pub fn toggleAll(self: *Self) void { |
| 632 | const bit_length = self.bit_length; |
| 633 | // avoid underflow if bit_length is zero |
| 634 | if (bit_length == 0) return; |
| 635 | |
| 636 | const num_masks = numMasks(self.bit_length); |
| 637 | for (self.masks[0..num_masks]) |*mask, i| { |
| 638 | mask.* = ~mask.*; |
| 639 | } |
| 640 | |
| 641 | const padding_bits = num_masks * @bitSizeOf(MaskInt) - bit_length; |
| 642 | const last_item_mask = (~@as(MaskInt, 0)) >> @intCast(ShiftInt, padding_bits); |
| 643 | self.masks[num_masks - 1] &= last_item_mask; |
| 644 | } |
| 645 | |
| 646 | /// Performs a union of two bit sets, and stores the |
| 647 | /// result in the first one. Bits in the result are |
| 648 | /// set if the corresponding bits were set in either input. |
| 649 | /// The two sets must both be the same bit_length. |
| 650 | pub fn setUnion(self: *Self, other: Self) void { |
| 651 | assert(other.bit_length == self.bit_length); |
| 652 | const num_masks = numMasks(self.bit_length); |
| 653 | for (self.masks[0..num_masks]) |*mask, i| { |
| 654 | mask.* |= other.masks[i]; |
| 655 | } |
| 656 | } |
| 657 | |
| 658 | /// Performs an intersection of two bit sets, and stores |
| 659 | /// the result in the first one. Bits in the result are |
| 660 | /// set if the corresponding bits were set in both inputs. |
| 661 | /// The two sets must both be the same bit_length. |
| 662 | pub fn setIntersection(self: *Self, other: Self) void { |
| 663 | assert(other.bit_length == self.bit_length); |
| 664 | const num_masks = numMasks(self.bit_length); |
| 665 | for (self.masks[0..num_masks]) |*mask, i| { |
| 666 | mask.* &= other.masks[i]; |
| 667 | } |
| 668 | } |
| 669 | |
| 670 | /// Finds the index of the first set bit. |
| 671 | /// If no bits are set, returns null. |
| 672 | pub fn findFirstSet(self: Self) ?usize { |
| 673 | var offset: usize = 0; |
| 674 | var mask = self.masks; |
| 675 | while (offset < self.bit_length) { |
| 676 | if (mask[0] != 0) break; |
| 677 | mask += 1; |
| 678 | offset += @bitSizeOf(MaskInt); |
| 679 | } else return null; |
| 680 | return offset + @ctz(MaskInt, mask[0]); |
| 681 | } |
| 682 | |
| 683 | /// Finds the index of the first set bit, and unsets it. |
| 684 | /// If no bits are set, returns null. |
| 685 | pub fn toggleFirstSet(self: *Self) ?usize { |
| 686 | var offset: usize = 0; |
| 687 | var mask = self.masks; |
| 688 | while (offset < self.bit_length) { |
| 689 | if (mask[0] != 0) break; |
| 690 | mask += 1; |
| 691 | offset += @bitSizeOf(MaskInt); |
| 692 | } else return null; |
| 693 | const index = @ctz(MaskInt, mask[0]); |
| 694 | mask[0] &= (mask[0]-1); |
| 695 | return offset + index; |
| 696 | } |
| 697 | |
| 698 | /// Iterates through the items in the set, according to the options. |
| 699 | /// The default options (.{}) will iterate indices of set bits in |
| 700 | /// ascending order. Modifications to the underlying bit set may |
| 701 | /// or may not be observed by the iterator. Resizing the underlying |
| 702 | /// bit set invalidates the iterator. |
| 703 | pub fn iterator(self: *const Self, comptime options: IteratorOptions) BitSetIterator(MaskInt, options) { |
| 704 | const num_masks = numMasks(self.bit_length); |
| 705 | const padding_bits = num_masks * @bitSizeOf(MaskInt) - self.bit_length; |
| 706 | const last_item_mask = (~@as(MaskInt, 0)) >> @intCast(ShiftInt, padding_bits); |
| 707 | return BitSetIterator(MaskInt, options).init(self.masks[0..num_masks], last_item_mask); |
| 708 | } |
| 709 | |
| 710 | fn maskBit(index: usize) MaskInt { |
| 711 | return @as(MaskInt, 1) << @truncate(ShiftInt, index); |
| 712 | } |
| 713 | fn maskIndex(index: usize) usize { |
| 714 | return index >> @bitSizeOf(ShiftInt); |
| 715 | } |
| 716 | fn boolMaskBit(index: usize, value: bool) MaskInt { |
| 717 | return @as(MaskInt, @boolToInt(value)) << @intCast(ShiftInt, index); |
| 718 | } |
| 719 | fn numMasks(bit_length: usize) usize { |
| 720 | return (bit_length + (@bitSizeOf(MaskInt) - 1)) / @bitSizeOf(MaskInt); |
| 721 | } |
| 722 | }; |
| 723 | |
| 724 | /// A bit set with runtime known size, backed by an allocated slice |
| 725 | /// of usize. Thin wrapper around DynamicBitSetUnmanaged which keeps |
| 726 | /// track of the allocator instance. |
| 727 | pub const DynamicBitSet = struct { |
| 728 | const Self = @This(); |
| 729 | |
| 730 | /// The integer type used to represent a mask in this bit set |
| 731 | pub const MaskInt = usize; |
| 732 | |
| 733 | /// The integer type used to shift a mask in this bit set |
| 734 | pub const ShiftInt = std.math.Log2Int(MaskInt); |
| 735 | |
| 736 | /// The allocator used by this bit set |
| 737 | allocator: *Allocator, |
| 738 | |
| 739 | /// The number of valid items in this bit set |
| 740 | unmanaged: DynamicBitSetUnmanaged = .{}, |
| 741 | |
| 742 | /// Creates a bit set with no elements present. |
| 743 | pub fn initEmpty(bit_length: usize, allocator: *Allocator) !Self { |
| 744 | return Self{ |
| 745 | .unmanaged = try DynamicBitSetUnmanaged.initEmpty(bit_length, allocator), |
| 746 | .allocator = allocator, |
| 747 | }; |
| 748 | } |
| 749 | |
| 750 | /// Creates a bit set with all elements present. |
| 751 | pub fn initFull(bit_length: usize, allocator: *Allocator) !Self { |
| 752 | return Self{ |
| 753 | .unmanaged = try DynamicBitSetUnmanaged.initFull(bit_length, allocator), |
| 754 | .allocator = allocator, |
| 755 | }; |
| 756 | } |
| 757 | |
| 758 | /// Resizes to a new length. If the new length is larger |
| 759 | /// than the old length, fills any added bits with `fill`. |
| 760 | pub fn resize(self: *@This(), new_len: usize, fill: bool) !void { |
| 761 | try self.unmanaged.resize(new_len, fill, self.allocator); |
| 762 | } |
| 763 | |
| 764 | /// deinitializes the array and releases its memory. |
| 765 | /// The passed allocator must be the same one used for |
| 766 | /// init* or resize in the past. |
| 767 | pub fn deinit(self: *Self) void { |
| 768 | self.unmanaged.deinit(self.allocator); |
| 769 | } |
| 770 | |
| 771 | /// Creates a duplicate of this bit set, using the new allocator. |
| 772 | pub fn clone(self: *const Self, new_allocator: *Allocator) !Self { |
| 773 | return Self{ |
| 774 | .unmanaged = try self.unmanaged.clone(new_allocator), |
| 775 | .allocator = new_allocator, |
| 776 | }; |
| 777 | } |
| 778 | |
| 779 | /// Returns the number of bits in this bit set |
| 780 | pub inline fn capacity(self: Self) usize { |
| 781 | return self.unmanaged.capacity(); |
| 782 | } |
| 783 | |
| 784 | /// Returns true if the bit at the specified index |
| 785 | /// is present in the set, false otherwise. |
| 786 | pub fn isSet(self: Self, index: usize) bool { |
| 787 | return self.unmanaged.isSet(index); |
| 788 | } |
| 789 | |
| 790 | /// Returns the total number of set bits in this bit set. |
| 791 | pub fn count(self: Self) usize { |
| 792 | return self.unmanaged.count(); |
| 793 | } |
| 794 | |
| 795 | /// Changes the value of the specified bit of the bit |
| 796 | /// set to match the passed boolean. |
| 797 | pub fn setValue(self: *Self, index: usize, value: bool) void { |
| 798 | self.unmanaged.setValue(index, value); |
| 799 | } |
| 800 | |
| 801 | /// Adds a specific bit to the bit set |
| 802 | pub fn set(self: *Self, index: usize) void { |
| 803 | self.unmanaged.set(index); |
| 804 | } |
| 805 | |
| 806 | /// Removes a specific bit from the bit set |
| 807 | pub fn unset(self: *Self, index: usize) void { |
| 808 | self.unmanaged.unset(index); |
| 809 | } |
| 810 | |
| 811 | /// Flips a specific bit in the bit set |
| 812 | pub fn toggle(self: *Self, index: usize) void { |
| 813 | self.unmanaged.toggle(index); |
| 814 | } |
| 815 | |
| 816 | /// Flips all bits in this bit set which are present |
| 817 | /// in the toggles bit set. Both sets must have the |
| 818 | /// same bit_length. |
| 819 | pub fn toggleSet(self: *Self, toggles: Self) void { |
| 820 | self.unmanaged.toggleSet(toggles.unmanaged); |
| 821 | } |
| 822 | |
| 823 | /// Flips every bit in the bit set. |
| 824 | pub fn toggleAll(self: *Self) void { |
| 825 | self.unmanaged.toggleAll(); |
| 826 | } |
| 827 | |
| 828 | /// Performs a union of two bit sets, and stores the |
| 829 | /// result in the first one. Bits in the result are |
| 830 | /// set if the corresponding bits were set in either input. |
| 831 | /// The two sets must both be the same bit_length. |
| 832 | pub fn setUnion(self: *Self, other: Self) void { |
| 833 | self.unmanaged.setUnion(other.unmanaged); |
| 834 | } |
| 835 | |
| 836 | /// Performs an intersection of two bit sets, and stores |
| 837 | /// the result in the first one. Bits in the result are |
| 838 | /// set if the corresponding bits were set in both inputs. |
| 839 | /// The two sets must both be the same bit_length. |
| 840 | pub fn setIntersection(self: *Self, other: Self) void { |
| 841 | self.unmanaged.setIntersection(other.unmanaged); |
| 842 | } |
| 843 | |
| 844 | /// Finds the index of the first set bit. |
| 845 | /// If no bits are set, returns null. |
| 846 | pub fn findFirstSet(self: Self) ?usize { |
| 847 | return self.unmanaged.findFirstSet(); |
| 848 | } |
| 849 | |
| 850 | /// Finds the index of the first set bit, and unsets it. |
| 851 | /// If no bits are set, returns null. |
| 852 | pub fn toggleFirstSet(self: *Self) ?usize { |
| 853 | return self.unmanaged.toggleFirstSet(); |
| 854 | } |
| 855 | |
| 856 | /// Iterates through the items in the set, according to the options. |
| 857 | /// The default options (.{}) will iterate indices of set bits in |
| 858 | /// ascending order. Modifications to the underlying bit set may |
| 859 | /// or may not be observed by the iterator. Resizing the underlying |
| 860 | /// bit set invalidates the iterator. |
| 861 | pub fn iterator(self: *Self, comptime options: IteratorOptions) BitSetIterator(MaskInt, options) { |
| 862 | return self.unmanaged.iterator(options); |
| 863 | } |
| 864 | }; |
| 865 | |
| 866 | /// Options for configuring an iterator over a bit set |
| 867 | pub const IteratorOptions = struct { |
| 868 | /// determines which bits should be visited |
| 869 | kind: Type = .set, |
| 870 | /// determines the order in which bit indices should be visited |
| 871 | direction: Direction = .forward, |
| 872 | |
| 873 | pub const Type = enum { |
| 874 | /// visit indexes of set bits |
| 875 | set, |
| 876 | /// visit indexes of unset bits |
| 877 | unset, |
| 878 | }; |
| 879 | |
| 880 | pub const Direction = enum { |
| 881 | /// visit indices in ascending order |
| 882 | forward, |
| 883 | /// visit indices in descending order. |
| 884 | /// Note that this may be slightly more expensive than forward iteration. |
| 885 | reverse, |
| 886 | }; |
| 887 | }; |
| 888 | |
| 889 | // The iterator is reusable between several bit set types |
| 890 | fn BitSetIterator(comptime MaskInt: type, comptime options: IteratorOptions) type { |
| 891 | const ShiftInt = std.math.Log2Int(MaskInt); |
| 892 | const kind = options.kind; |
| 893 | const direction = options.direction; |
| 894 | return struct { |
| 895 | const Self = @This(); |
| 896 | |
| 897 | // all bits which have not yet been iterated over |
| 898 | bits_remain: MaskInt, |
| 899 | // all words which have not yet been iterated over |
| 900 | words_remain: []const MaskInt, |
| 901 | // the offset of the current word |
| 902 | bit_offset: usize, |
| 903 | // the mask of the last word |
| 904 | last_word_mask: MaskInt, |
| 905 | |
| 906 | fn init(masks: []const MaskInt, last_word_mask: MaskInt) Self { |
| 907 | if (masks.len == 0) { |
| 908 | return Self{ |
| 909 | .bits_remain = 0, |
| 910 | .words_remain = &[_]MaskInt{}, |
| 911 | .last_word_mask = last_word_mask, |
| 912 | .bit_offset = 0, |
| 913 | }; |
| 914 | } else { |
| 915 | var result = Self{ |
| 916 | .bits_remain = 0, |
| 917 | .words_remain = masks, |
| 918 | .last_word_mask = last_word_mask, |
| 919 | .bit_offset = if (direction == .forward) 0 else (masks.len - 1) * @bitSizeOf(MaskInt), |
| 920 | }; |
| 921 | result.nextWord(true); |
| 922 | return result; |
| 923 | } |
| 924 | } |
| 925 | |
| 926 | /// Returns the index of the next unvisited set bit |
| 927 | /// in the bit set, in ascending order. |
| 928 | pub fn next(self: *Self) ?usize { |
| 929 | while (self.bits_remain == 0) { |
| 930 | if (self.words_remain.len == 0) return null; |
| 931 | self.nextWord(false); |
| 932 | switch (direction) { |
| 933 | .forward => self.bit_offset += @bitSizeOf(MaskInt), |
| 934 | .reverse => self.bit_offset -= @bitSizeOf(MaskInt), |
| 935 | } |
| 936 | } |
| 937 | |
| 938 | switch (direction) { |
| 939 | .forward => { |
| 940 | const next_index = @ctz(MaskInt, self.bits_remain) + self.bit_offset; |
| 941 | self.bits_remain &= self.bits_remain - 1; |
| 942 | return next_index; |
| 943 | }, |
| 944 | .reverse => { |
| 945 | const leading_zeroes = @clz(MaskInt, self.bits_remain); |
| 946 | const top_bit = (@bitSizeOf(MaskInt) - 1) - leading_zeroes; |
| 947 | const no_top_bit_mask = (@as(MaskInt, 1) << @intCast(ShiftInt, top_bit)) - 1; |
| 948 | self.bits_remain &= no_top_bit_mask; |
| 949 | return top_bit + self.bit_offset; |
| 950 | }, |
| 951 | } |
| 952 | } |
| 953 | |
| 954 | // Load the next word. Don't call this if there |
| 955 | // isn't a next word. If the next word is the |
| 956 | // last word, mask off the padding bits so we |
| 957 | // don't visit them. |
| 958 | inline fn nextWord(self: *Self, comptime is_first_word: bool) void { |
| 959 | var word = switch (direction) { |
| 960 | .forward => self.words_remain[0], |
| 961 | .reverse => self.words_remain[self.words_remain.len - 1], |
| 962 | }; |
| 963 | switch (kind) { |
| 964 | .set => {}, |
| 965 | .unset => { |
| 966 | word = ~word; |
| 967 | if ((direction == .reverse and is_first_word) or |
| 968 | (direction == .forward and self.words_remain.len == 1)) |
| 969 | { |
| 970 | word &= self.last_word_mask; |
| 971 | } |
| 972 | }, |
| 973 | } |
| 974 | switch (direction) { |
| 975 | .forward => self.words_remain = self.words_remain[1..], |
| 976 | .reverse => self.words_remain.len -= 1, |
| 977 | } |
| 978 | self.bits_remain = word; |
| 979 | } |
| 980 | }; |
| 981 | } |
| 982 | |
| 983 | // ---------------- Tests ----------------- |
| 984 | |
| 985 | const testing = std.testing; |
| 986 | |
| 987 | fn testBitSet(a: anytype, b: anytype, len: usize) void { |
| 988 | testing.expectEqual(len, a.capacity()); |
| 989 | testing.expectEqual(len, b.capacity()); |
| 990 | |
| 991 | { |
| 992 | var i: usize = 0; |
| 993 | while (i < len) : (i += 1) { |
| 994 | a.setValue(i, i & 1 == 0); |
| 995 | b.setValue(i, i & 2 == 0); |
| 996 | } |
| 997 | } |
| 998 | |
| 999 | testing.expectEqual((len + 1) / 2, a.count()); |
| 1000 | testing.expectEqual((len + 3) / 4 + (len + 2) / 4, b.count()); |
| 1001 | |
| 1002 | { |
| 1003 | var iter = a.iterator(.{}); |
| 1004 | var i: usize = 0; |
| 1005 | while (i < len) : (i += 2) { |
| 1006 | testing.expectEqual(@as(?usize, i), iter.next()); |
| 1007 | } |
| 1008 | testing.expectEqual(@as(?usize, null), iter.next()); |
| 1009 | testing.expectEqual(@as(?usize, null), iter.next()); |
| 1010 | testing.expectEqual(@as(?usize, null), iter.next()); |
| 1011 | } |
| 1012 | a.toggleAll(); |
| 1013 | { |
| 1014 | var iter = a.iterator(.{}); |
| 1015 | var i: usize = 1; |
| 1016 | while (i < len) : (i += 2) { |
| 1017 | testing.expectEqual(@as(?usize, i), iter.next()); |
| 1018 | } |
| 1019 | testing.expectEqual(@as(?usize, null), iter.next()); |
| 1020 | testing.expectEqual(@as(?usize, null), iter.next()); |
| 1021 | testing.expectEqual(@as(?usize, null), iter.next()); |
| 1022 | } |
| 1023 | |
| 1024 | { |
| 1025 | var iter = b.iterator(.{ .kind = .unset }); |
| 1026 | var i: usize = 2; |
| 1027 | while (i < len) : (i += 4) { |
| 1028 | testing.expectEqual(@as(?usize, i), iter.next()); |
| 1029 | if (i + 1 < len) { |
| 1030 | testing.expectEqual(@as(?usize, i + 1), iter.next()); |
| 1031 | } |
| 1032 | } |
| 1033 | testing.expectEqual(@as(?usize, null), iter.next()); |
| 1034 | testing.expectEqual(@as(?usize, null), iter.next()); |
| 1035 | testing.expectEqual(@as(?usize, null), iter.next()); |
| 1036 | } |
| 1037 | |
| 1038 | { |
| 1039 | var i: usize = 0; |
| 1040 | while (i < len) : (i += 1) { |
| 1041 | testing.expectEqual(i & 1 != 0, a.isSet(i)); |
| 1042 | testing.expectEqual(i & 2 == 0, b.isSet(i)); |
| 1043 | } |
| 1044 | } |
| 1045 | |
| 1046 | a.setUnion(b.*); |
| 1047 | { |
| 1048 | var i: usize = 0; |
| 1049 | while (i < len) : (i += 1) { |
| 1050 | testing.expectEqual(i & 1 != 0 or i & 2 == 0, a.isSet(i)); |
| 1051 | testing.expectEqual(i & 2 == 0, b.isSet(i)); |
| 1052 | } |
| 1053 | |
| 1054 | i = len; |
| 1055 | var set = a.iterator(.{ .direction = .reverse }); |
| 1056 | var unset = a.iterator(.{ .kind = .unset, .direction = .reverse }); |
| 1057 | while (i > 0) { |
| 1058 | i -= 1; |
| 1059 | if (i & 1 != 0 or i & 2 == 0) { |
| 1060 | testing.expectEqual(@as(?usize, i), set.next()); |
| 1061 | } else { |
| 1062 | testing.expectEqual(@as(?usize, i), unset.next()); |
| 1063 | } |
| 1064 | } |
| 1065 | testing.expectEqual(@as(?usize, null), set.next()); |
| 1066 | testing.expectEqual(@as(?usize, null), set.next()); |
| 1067 | testing.expectEqual(@as(?usize, null), set.next()); |
| 1068 | testing.expectEqual(@as(?usize, null), unset.next()); |
| 1069 | testing.expectEqual(@as(?usize, null), unset.next()); |
| 1070 | testing.expectEqual(@as(?usize, null), unset.next()); |
| 1071 | } |
| 1072 | |
| 1073 | a.toggleSet(b.*); |
| 1074 | { |
| 1075 | testing.expectEqual(len / 4, a.count()); |
| 1076 | |
| 1077 | var i: usize = 0; |
| 1078 | while (i < len) : (i += 1) { |
| 1079 | testing.expectEqual(i & 1 != 0 and i & 2 != 0, a.isSet(i)); |
| 1080 | testing.expectEqual(i & 2 == 0, b.isSet(i)); |
| 1081 | if (i & 1 == 0) { |
| 1082 | a.set(i); |
| 1083 | } else { |
| 1084 | a.unset(i); |
| 1085 | } |
| 1086 | } |
| 1087 | } |
| 1088 | |
| 1089 | a.setIntersection(b.*); |
| 1090 | { |
| 1091 | testing.expectEqual((len + 3) / 4, a.count()); |
| 1092 | |
| 1093 | var i: usize = 0; |
| 1094 | while (i < len) : (i += 1) { |
| 1095 | testing.expectEqual(i & 1 == 0 and i & 2 == 0, a.isSet(i)); |
| 1096 | testing.expectEqual(i & 2 == 0, b.isSet(i)); |
| 1097 | } |
| 1098 | } |
| 1099 | |
| 1100 | a.toggleSet(a.*); |
| 1101 | { |
| 1102 | var iter = a.iterator(.{}); |
| 1103 | testing.expectEqual(@as(?usize, null), iter.next()); |
| 1104 | testing.expectEqual(@as(?usize, null), iter.next()); |
| 1105 | testing.expectEqual(@as(?usize, null), iter.next()); |
| 1106 | testing.expectEqual(@as(usize, 0), a.count()); |
| 1107 | } |
| 1108 | { |
| 1109 | var iter = a.iterator(.{ .direction = .reverse }); |
| 1110 | testing.expectEqual(@as(?usize, null), iter.next()); |
| 1111 | testing.expectEqual(@as(?usize, null), iter.next()); |
| 1112 | testing.expectEqual(@as(?usize, null), iter.next()); |
| 1113 | testing.expectEqual(@as(usize, 0), a.count()); |
| 1114 | } |
| 1115 | |
| 1116 | const test_bits = [_]usize{ |
| 1117 | 0, 1, 2, 3, 4, 5, 6, 7, 9, 10, 11, 22, 31, 32, 63, 64, |
| 1118 | 66, 95, 127, 160, 192, 1000 }; |
| 1119 | for (test_bits) |i| { |
| 1120 | if (i < a.capacity()) { |
| 1121 | a.set(i); |
| 1122 | } |
| 1123 | } |
| 1124 | |
| 1125 | for (test_bits) |i| { |
| 1126 | if (i < a.capacity()) { |
| 1127 | testing.expectEqual(@as(?usize, i), a.findFirstSet()); |
| 1128 | testing.expectEqual(@as(?usize, i), a.toggleFirstSet()); |
| 1129 | } |
| 1130 | } |
| 1131 | testing.expectEqual(@as(?usize, null), a.findFirstSet()); |
| 1132 | testing.expectEqual(@as(?usize, null), a.toggleFirstSet()); |
| 1133 | testing.expectEqual(@as(?usize, null), a.findFirstSet()); |
| 1134 | testing.expectEqual(@as(?usize, null), a.toggleFirstSet()); |
| 1135 | testing.expectEqual(@as(usize, 0), a.count()); |
| 1136 | } |
| 1137 | |
| 1138 | fn testStaticBitSet(comptime Set: type) void { |
| 1139 | var a = Set.initEmpty(); |
| 1140 | var b = Set.initFull(); |
| 1141 | testing.expectEqual(@as(usize, 0), a.count()); |
| 1142 | testing.expectEqual(@as(usize, Set.bit_length), b.count()); |
| 1143 | |
| 1144 | testBitSet(&a, &b, Set.bit_length); |
| 1145 | } |
| 1146 | |
| 1147 | test "IntegerBitSet" { |
| 1148 | testStaticBitSet(IntegerBitSet(0)); |
| 1149 | testStaticBitSet(IntegerBitSet(1)); |
| 1150 | testStaticBitSet(IntegerBitSet(2)); |
| 1151 | testStaticBitSet(IntegerBitSet(5)); |
| 1152 | testStaticBitSet(IntegerBitSet(8)); |
| 1153 | testStaticBitSet(IntegerBitSet(32)); |
| 1154 | testStaticBitSet(IntegerBitSet(64)); |
| 1155 | testStaticBitSet(IntegerBitSet(127)); |
| 1156 | } |
| 1157 | |
| 1158 | test "ArrayBitSet" { |
| 1159 | inline for (.{ 0, 1, 2, 31, 32, 33, 63, 64, 65, 254, 500, 3000 }) |size| { |
| 1160 | testStaticBitSet(ArrayBitSet(u8, size)); |
| 1161 | testStaticBitSet(ArrayBitSet(u16, size)); |
| 1162 | testStaticBitSet(ArrayBitSet(u32, size)); |
| 1163 | testStaticBitSet(ArrayBitSet(u64, size)); |
| 1164 | testStaticBitSet(ArrayBitSet(u128, size)); |
| 1165 | } |
| 1166 | } |
| 1167 | |
| 1168 | test "DynamicBitSetUnmanaged" { |
| 1169 | const allocator = std.testing.allocator; |
| 1170 | var a = try DynamicBitSetUnmanaged.initEmpty(300, allocator); |
| 1171 | testing.expectEqual(@as(usize, 0), a.count()); |
| 1172 | a.deinit(allocator); |
| 1173 | |
| 1174 | a = try DynamicBitSetUnmanaged.initEmpty(0, allocator); |
| 1175 | defer a.deinit(allocator); |
| 1176 | for ([_]usize{ 1, 2, 31, 32, 33, 0, 65, 64, 63, 500, 254, 3000 }) |size| { |
| 1177 | const old_len = a.capacity(); |
| 1178 | |
| 1179 | var tmp = try a.clone(allocator); |
| 1180 | defer tmp.deinit(allocator); |
| 1181 | testing.expectEqual(old_len, tmp.capacity()); |
| 1182 | var i: usize = 0; |
| 1183 | while (i < old_len) : (i += 1) { |
| 1184 | testing.expectEqual(a.isSet(i), tmp.isSet(i)); |
| 1185 | } |
| 1186 | |
| 1187 | a.toggleSet(a); // zero a |
| 1188 | tmp.toggleSet(tmp); |
| 1189 | |
| 1190 | try a.resize(size, true, allocator); |
| 1191 | try tmp.resize(size, false, allocator); |
| 1192 | |
| 1193 | if (size > old_len) { |
| 1194 | testing.expectEqual(size - old_len, a.count()); |
| 1195 | } else { |
| 1196 | testing.expectEqual(@as(usize, 0), a.count()); |
| 1197 | } |
| 1198 | testing.expectEqual(@as(usize, 0), tmp.count()); |
| 1199 | |
| 1200 | var b = try DynamicBitSetUnmanaged.initFull(size, allocator); |
| 1201 | defer b.deinit(allocator); |
| 1202 | testing.expectEqual(@as(usize, size), b.count()); |
| 1203 | |
| 1204 | testBitSet(&a, &b, size); |
| 1205 | } |
| 1206 | } |
| 1207 | |
| 1208 | test "DynamicBitSet" { |
| 1209 | const allocator = std.testing.allocator; |
| 1210 | var a = try DynamicBitSet.initEmpty(300, allocator); |
| 1211 | testing.expectEqual(@as(usize, 0), a.count()); |
| 1212 | a.deinit(); |
| 1213 | |
| 1214 | a = try DynamicBitSet.initEmpty(0, allocator); |
| 1215 | defer a.deinit(); |
| 1216 | for ([_]usize{ 1, 2, 31, 32, 33, 0, 65, 64, 63, 500, 254, 3000 }) |size| { |
| 1217 | const old_len = a.capacity(); |
| 1218 | |
| 1219 | var tmp = try a.clone(allocator); |
| 1220 | defer tmp.deinit(); |
| 1221 | testing.expectEqual(old_len, tmp.capacity()); |
| 1222 | var i: usize = 0; |
| 1223 | while (i < old_len) : (i += 1) { |
| 1224 | testing.expectEqual(a.isSet(i), tmp.isSet(i)); |
| 1225 | } |
| 1226 | |
| 1227 | a.toggleSet(a); // zero a |
| 1228 | tmp.toggleSet(tmp); // zero tmp |
| 1229 | |
| 1230 | try a.resize(size, true); |
| 1231 | try tmp.resize(size, false); |
| 1232 | |
| 1233 | if (size > old_len) { |
| 1234 | testing.expectEqual(size - old_len, a.count()); |
| 1235 | } else { |
| 1236 | testing.expectEqual(@as(usize, 0), a.count()); |
| 1237 | } |
| 1238 | testing.expectEqual(@as(usize, 0), tmp.count()); |
| 1239 | |
| 1240 | var b = try DynamicBitSet.initFull(size, allocator); |
| 1241 | defer b.deinit(); |
| 1242 | testing.expectEqual(@as(usize, size), b.count()); |
| 1243 | |
| 1244 | testBitSet(&a, &b, size); |
| 1245 | } |
| 1246 | } |
| 1247 | |
| 1248 | test "StaticBitSet" { |
| 1249 | testing.expectEqual(IntegerBitSet(0), StaticBitSet(0)); |
| 1250 | testing.expectEqual(IntegerBitSet(5), StaticBitSet(5)); |
| 1251 | testing.expectEqual(IntegerBitSet(@bitSizeOf(usize)), StaticBitSet(@bitSizeOf(usize))); |
| 1252 | testing.expectEqual(ArrayBitSet(usize, @bitSizeOf(usize) + 1), StaticBitSet(@bitSizeOf(usize) + 1)); |
| 1253 | testing.expectEqual(ArrayBitSet(usize, 500), StaticBitSet(500)); |
| 1254 | } |
Martin Wickham <spexguy070@gmail.com> 2021-02-04 23:04:49-06:00
Andrew Kelley <andrew@ziglang.org> 2021-03-01 18:52:15-08:00