-
Notifications
You must be signed in to change notification settings - Fork 0
/
index.js
535 lines (463 loc) · 18.1 KB
/
index.js
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
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
/* @flow */
import Backing from "backing";
import {TypedObject} from "../";
import {alignTo} from "../../util";
import type {Realm} from "../../";
import {
$Backing,
$Address,
$CanBeEmbedded,
$CanBeReferenced,
$CanContainReferences,
$ElementType,
$GetElement,
$SetElement
} from "../../symbols";
export type ForEachVisitor = (element: any, index: uint32, context: HashSet) => void;
export type MapVisitor = (element: any, index: uint32, context: HashSet) => any;
export type FilterVisitor = (element: any, index: uint32, context: HashSet) => boolean;
export class HashSet<E> extends TypedObject {
/**
* Return the size of the hash set.
*/
get size (): uint32 {
// @flowIssue 252
return this[$Backing].getUint32(this[$Address] + CARDINALITY_OFFSET);
}
/**
* Add the given entry to the set if it does not already exist.
*/
add (entry: E): HashSet<E> {
return this;
}
/**
* Determine whether the hash set contains the given entry or not.
*/
has (entry: E): boolean {
return false;
}
/**
* Deletes an entry from the hash set.
* Returns `true` if the given entry was deleted, otherwise `false`.
*/
delete (entry: E): boolean {
return false;
}
}
const HEADER_SIZE = 16;
const ARRAY_POINTER_OFFSET = 0;
const ARRAY_LENGTH_OFFSET = 8;
const CARDINALITY_OFFSET = 12;
const INITIAL_BUCKET_COUNT = 16;
/**
* Makes a HashSetType type class for the given realm.
*/
export function make (realm: Realm): TypeClass<HashSetType<Type, Type>> {
const {TypeClass, StructType, ReferenceType, T, backing, registry} = realm;
const idRange = registry.range('HashSetType');
return new TypeClass('HashSetType', (EntryType: Type, config: Object = {}): Function => {
return (Partial: Function) => {
const name = typeof config.name === 'string' ? config.name : `HashSet<${EntryType.name}>`;
if (realm.T[name]) {
return realm.T[name];
}
const id = typeof config.id === 'number' ? config.id : idRange.next();
type AcceptableInput = Set|TypedHashSet<EntryType>|EntryType|Object;
Partial[$CanBeEmbedded] = false;
Partial[$CanBeReferenced] = true;
Partial[$CanContainReferences] = true;
Object.defineProperties(Partial, {
id: {
value: id,
},
name: {
value: name
}
});
Partial.ref = new ReferenceType(Partial);
function getArrayAddress (backing: Backing, address: float64): float64 {
return backing.getFloat64(address);
}
function setArrayAddress (backing: Backing, address: float64, value: float64): void {
backing.setFloat64(address, value);
}
function getArrayLength (backing: Backing, address: float64): float64 {
return backing.getUint32(address + ARRAY_LENGTH_OFFSET);
}
function setArrayLength (backing: Backing, address: float64, value: float64): void {
backing.setUint32(address + ARRAY_LENGTH_OFFSET, value);
}
function getCardinality (backing: Backing, address: float64): uint32 {
return backing.getUint32(address + CARDINALITY_OFFSET);
}
function setCardinality (backing: Backing, address: float64, value: uint32): void {
backing.setUint32(address + CARDINALITY_OFFSET, value);
}
const Bucket = new StructType([
['hash', T.Uint32],
['entry', EntryType]
]);
const ENTRY_OFFSET = Bucket.fieldOffsets.entry;
const BUCKET_SIZE = alignTo(Bucket.byteLength, Bucket.byteAlignment);
function getBucketHash (backing: Backing, bucketAddress: float64): uint32 {
return backing.getUint32(bucketAddress);
}
function setBucketHash (backing: Backing, bucketAddress: float64, value: uint32): void {
backing.setUint32(bucketAddress, value);
}
function getBucketEntry (backing: Backing, bucketAddress: float64): any {
return EntryType.load(backing, bucketAddress + ENTRY_OFFSET);
}
function setBucketEntry (backing: Backing, bucketAddress: float64, value: any) {
return EntryType.store(backing, bucketAddress + ENTRY_OFFSET, value);
}
/**
* The constructor for this kind of hash set.
*/
function constructor (backingOrInput: ?Backing|AcceptableInput, address?: float64) {
if (backingOrInput instanceof Backing) {
this[$Backing] = backingOrInput;
this[$Address] = address;
}
else {
this[$Backing] = backing;
this[$Address] = createHashSetAt(backing, backing.gc.calloc(HEADER_SIZE, id), backingOrInput);
}
this[$CanBeReferenced] = true;
}
/**
* Create a new hash set from the given input and return its address.
*/
function createHashSetAt (backing: Backing, address: float64, input: ?AcceptableInput): float64 {
if (input == null) {
createEmptyHashSet(backing, address);
}
else if (Array.isArray(input)) {
createHashSetFromArray(backing, address, input);
}
// @flowIssue 252
else if (typeof input[Symbol.iterator] === 'function') {
createHashSetFromIterable(backing, address, input);
}
else {
throw new TypeError(`Cannot create a ${name} from invalid input.`);
}
return address;
}
/**
* Create an empty hashset with a bucket array.
* Use `initialCardinalityHint` to pre-allocate a bucket array which can
* handle at least the given number of entries. Note that specifying this
* argument does not actually write the cardinality value.
*/
function createEmptyHashSet (backing: Backing, header: float64, initialCardinalityHint: uint32 = 0): float64 {
let initialSize;
if ((initialCardinalityHint * 2) < INITIAL_BUCKET_COUNT) {
initialSize = INITIAL_BUCKET_COUNT;
}
else {
initialSize = initialCardinalityHint * 2;
}
const body = backing.calloc(initialSize * BUCKET_SIZE);
setArrayAddress(backing, header, body);
setArrayLength(backing, header, initialSize);
return header;
}
/**
* Create a hashset from an array of entries.
*/
function createHashSetFromArray (backing: Backing, header: float64, input: Array<EntryType>): void {
const length = input.length;
createEmptyHashSet(backing, header, length);
for (let i = 0; i < length; i++) {
const entry = input[i];
const hash: uint32 = EntryType.hashValue((entry: any));
lookupOrInsert(backing, header, entry, hash);
}
}
/**
* Create a hashset from an iterable.
*/
function createHashSetFromIterable (backing: Backing, header: float64, input: $Fixme<Iterable<EntryType>>): void {
createEmptyHashSet(backing, header);
for (const entry of input) {
const hash: uint32 = EntryType.hashValue((entry: any));
lookupOrInsert(backing, header, entry, hash);
}
}
/**
* Return the appropriate bucket for the given entry + hash.
*/
function probe (backing: Backing, header: float64, entry: any, hash: uint32): float64 {
const bucketArrayLength = getArrayLength(backing, header);
const bucketArrayAddress = getArrayAddress(backing, header);
let index = (hash & (bucketArrayLength - 1));
let address: float64 = bucketArrayAddress + (index * BUCKET_SIZE);
let bucketHash = getBucketHash(backing, address);
while (bucketHash !== 0 && (bucketHash !== hash || !EntryType.equal(entry, getBucketEntry(backing, address)))) {
index++;
if (index >= bucketArrayLength) {
index = 0;
}
address = bucketArrayAddress + (index * BUCKET_SIZE);
bucketHash = getBucketHash(backing, address);
}
return address;
}
/**
* Find the address of the bucket for the given entry + hash, or 0 if it does not exist.
*/
function lookup (backing: Backing, header: float64, entry: any, hash: uint32): float64 {
const address: float64 = probe(backing, header, entry, hash);
return getBucketHash(backing, address) === 0 ? 0 : address;
}
/**
* Find the address of the bucket for the given entry + hash, or create it if it does not exist.
*/
function lookupOrInsert (backing: Backing, header: float64, entry: any, hash: uint32): float64 {
const bucketArrayLength = getArrayLength(backing, header);
const address: float64 = probe(backing, header, entry, hash);
if (getBucketHash(backing, address) !== 0) {
return address;
}
trace: `No entry found for entry ${entry}, inserting one.`;
setBucketEntry(backing, address, entry);
setBucketHash(backing, address, hash);
const cardinality = getCardinality(backing, header) + 1;
setCardinality(backing, header, cardinality);
if (cardinality + (cardinality >> 2) >= bucketArrayLength) {
trace: `Growing the hash set because we reached >= 80% occupancy.`;
grow(backing, header);
return probe(backing, header, entry, hash);
}
else {
return address;
}
}
/**
* Remove the given entry + hash from the hash set.
*/
function remove (backing: Backing, header: float64, entry: any, hash: uint32): boolean {
let p: float64 = probe(backing, header, entry, hash);
if (getBucketHash(backing, p) === 0) {
return false;
}
const bucketArrayLength = getArrayLength(backing, header);
const bucketArrayAddress = getArrayAddress(backing, header);
const end = bucketArrayAddress + (bucketArrayLength * BUCKET_SIZE);
// @fixme free the bucket value?
let q: float64 = p;
while (true) {
// Move q to the next entry
q = q + BUCKET_SIZE;
if (q === end) {
q = bucketArrayAddress;
}
const qHash = getBucketHash(backing, q);
// All entries between p and q have their initial position between p and q
// and the entry p can be cleared without breaking the search for these
// entries.
if (qHash === 0) {
break;
}
// Find the initial position for the entry at position q.
const r: float64 = bucketArrayAddress + ((qHash & (bucketArrayLength - 1)) * BUCKET_SIZE);
// If the entry at position q has its initial position outside the range
// between p and q it can be moved forward to position p and will still be
// found. There is now a new candidate entry for clearing.
if ((q > p && (r <= p || r > q)) ||
(q < p && (r <= p && r > q))) {
backing.copy(p, q, BUCKET_SIZE);
p = q;
}
}
setBucketHash(backing, p, 0);
const cardinality = getCardinality(backing, header);
assert: cardinality > 0;
setCardinality(backing, header, cardinality - 1);
return true;
}
/**
* Grow the backing array to twice its current capacity.
*/
function grow (backing: Backing, header: float64): void {
const bucketArrayLength = getArrayLength(backing, header);
const bucketArrayAddress = getArrayAddress(backing, header);
const cardinality = getCardinality(backing, header);
const newBuckets = backing.calloc(bucketArrayLength * 2 * BUCKET_SIZE);
setArrayAddress(backing, header, newBuckets);
setArrayLength(backing, header, bucketArrayLength * 2);
setCardinality(backing, header, 1);
for (let index = 0; index < bucketArrayLength; index++) {
const oldAddress = bucketArrayAddress + (index * BUCKET_SIZE);
const bucketHash = getBucketHash(backing, oldAddress);
if (bucketHash !== 0) {
trace: `Copying entry ${getBucketEntry(backing, oldAddress)} ${bucketHash}`;
lookupOrInsert(backing, header, getBucketEntry(backing, oldAddress), bucketHash);
}
}
setCardinality(backing, header, cardinality);
backing.free(bucketArrayAddress);
}
/**
* Destroy the hashset at the given address, along with all its contents.
*/
function destructor (backing: Backing, header: float64): void {
const bucketArrayAddress = getArrayAddress(backing, header);
if (bucketArrayAddress !== 0) {
const bucketArrayLength = getArrayLength(backing, header);
let current = bucketArrayAddress;
for (let index = 0; index < bucketArrayLength; index++) {
Bucket.destructor(backing, current);
current += BUCKET_SIZE;
}
setArrayAddress(backing, header, 0);
setArrayLength(backing, header, 0);
backing.free(bucketArrayAddress);
}
}
const prototype = Object.create(HashSet.prototype, {
/**
* Add the given entry to the hash set.
*/
add: {
value (entry: EntryType): HashSet<EntryType> {
const hash: uint32 = EntryType.hashValue((entry: any));
lookupOrInsert(this[$Backing], this[$Address], entry, hash);
return this;
}
},
/**
* Determine whether the hash set contains the given entry or not.
*/
has: {
value (entry: EntryType): boolean {
const hash: uint32 = EntryType.hashValue((entry: any));
return lookup(this[$Backing], this[$Address], entry, hash) !== 0;
}
},
/**
* Deletes an entry from the hash set.
* Returns `true` if the given entry was deleted, otherwise `false`.
*/
delete: {
value (entry: EntryType): boolean {
const hash: uint32 = EntryType.hashValue((entry: any));
return remove(this[$Backing], this[$Address], entry, hash);
}
},
/**
* Return a representation of the hash set which can be encoded as JSON.
*/
toJSON: {
value (): EntryType[] {
const backing = this[$Backing];
const address = this[$Address];
const size = getCardinality(backing, address);
const bucketArrayLength = getArrayLength(backing, address);
const arr = new Array(size);
let current: float64 = getArrayAddress(backing, address);
let index: uint32 = 0;
for (let i = 0; i < bucketArrayLength; i++) {
if (getBucketHash(backing, current) !== 0) {
arr[index++] = getBucketEntry(backing, current);
}
current += BUCKET_SIZE;
}
return arr;
}
},
/**
* Iterate the key / values in the set.
* IMPORTANT: The iteration order is not stable and should not be relied on!
* It is guaranteed that every entry will be yielded exactly once, but the order
* depends on the hashed value and the size of the backing array.
* If you need ordered iteration, use a SkipListSet.
*/
[Symbol.iterator]: {
*value () {
let backing = this[$Backing];
let address = this[$Address];
let bucketArrayLength = getArrayLength(backing, address);
let current: float64 = getArrayAddress(backing, address);
for (let index = 0; index < bucketArrayLength; index++) {
if (getBucketHash(backing, current) !== 0) {
yield getBucketEntry(backing, current);
}
current += BUCKET_SIZE;
}
}
}
});
return {
id,
name,
byteLength: 8,
byteAlignment: 8,
constructor,
prototype,
accepts (input: any): boolean {
return input !== null && typeof input === 'object';
},
initialize (backing: Backing, pointerAddress: float64, initialValue?: AcceptableInput): void {
const address = backing.gc.alloc(HEADER_SIZE, Partial.id, 1);
createHashSetAt(backing, address, initialValue);
backing.setFloat64(pointerAddress, address);
},
store (backing: Backing, pointerAddress: float64, input?: AcceptableInput): void {
const existing = backing.getFloat64(pointerAddress);
if (existing !== 0) {
backing.setFloat64(pointerAddress, 0);
backing.gc.unref(existing);
}
const address = backing.gc.alloc(HEADER_SIZE, Partial.id, 1);
createHashSetAt(backing, address, input);
backing.setFloat64(pointerAddress, address);
},
load (backing: Backing, pointerAddress: float64): ?Partial {
const address = backing.getFloat64(pointerAddress);
return address === 0 ? null : new Partial(backing, address);
},
clear (backing: Backing, pointerAddress: float64) {
const address = backing.getFloat64(pointerAddress);
if (address !== 0) {
backing.setFloat64(pointerAddress, 0);
backing.gc.unref(address);
}
},
destructor: destructor,
equal (setA: TypedHashSet<EntryType>, setB: TypedHashSet<EntryType>): boolean {
if (setA[$Backing] === setB[$Backing] && setA[$Address] === setB[$Address]) {
return true;
}
else if (setA.size !== setB.size) {
return false;
}
for (const key of setA) {
if (!setB.has(key)) {
return false;
}
}
return true;
},
randomValue (): TypedHashSet<EntryType> {
const set = new Partial();
const size = Math.ceil(Math.random() * 32);
for (let i = 0; i < size; i++) {
set.add(EntryType.randomValue());
}
return set;
},
emptyValue (): Partial {
return new Partial();
},
flowType () {
return `HashSet<${EntryType.flowType()}>`;
},
hashValue (input: TypedHashSet<EntryType>): uint32 {
return input[$Address];
}
};
};
});
}