35 // - Enums are stored in buckets (64 contiguous values max per bucket)
42 //      - bucket 0, storing values in the range [ 0;  64[
43 //      - bucket 1, storing values in the range [64; 128[
45 // - Buckets are stored in a sorted vector (sorted by bucket range).
46 // - Retrieval is done by computing the theoretical bucket index using the enum
49 // - Insertion is done by retrieving the bucket and either:
50 //   - inserting a new bucket in the sorted vector when no buckets has a
52 //   - setting the corresponding bit in the bucket.
54 //   bucket is available. In our case, this happens at most 23 times for the
65   // Each bucket can hold up to `kBucketSize` distinct, contiguous enum values.
66   // The first value a bucket can hold must be aligned on `kBucketSize`.
67   struct Bucket {  struct
70     // 1st enum this bucket can represent.
73     friend bool operator==(const Bucket& lhs, const Bucket& rhs) {  argument
78   // How many distinct values can a bucket hold? 1 bit per value.
150     // Index of the bucket in the vector.
152     // Offset in bits in the current bucket.
242     auto& bucket = buckets_[index];  in insert()  local
244     if (bucket.data & mask) {  in insert()
249     bucket.data |= ComputeMaskForValue(value);  in insert()
286     auto& bucket = buckets_[index];  in erase()  local
288     if (!(bucket.data & mask)) {  in erase()
293     bucket.data &= ~mask;  in erase()
294     if (bucket.data == 0) {  in erase()
307     auto& bucket = buckets_[index];  in contains()  local
308     return bucket.data & ComputeMaskForValue(value);  in contains()
342       // LHS bucket is smaller than the current RHS bucket. Catching up on RHS.  in HasAnyOf()
356   // Returns the index of the last bucket in which `value` could be stored.
361   // Returns the smallest enum value that could be contained in the same bucket
368   //  Returns the index of the bit that corresponds to `value` in the bucket.
373   // Returns the bitmask used to represent the enum `value` in its bucket.
378   // Returns the `enum` stored in `bucket` at `offset`.
379   // `offset` is the bit-offset in the bucket storage.
380   static constexpr inline T GetValueFromBucket(const Bucket& bucket,  in GetValueFromBucket()  argument
382     return static_cast<T>(static_cast<ElementType>(bucket.start) + offset);  in GetValueFromBucket()
385   // For a given enum `value`, finds the bucket index that could contain this
386   // value. If no such bucket is found, the index at which the new bucket should
402     //  - The bucket matches  in FindBucketForValue()
403     //    => returns the bucket index.  in FindBucketForValue()
404     //  - The found bucket is larger  in FindBucketForValue()
405     //    => scans left until it finds the correct bucket, or insertion point.  in FindBucketForValue()
406     //  - The found bucket is smaller  in FindBucketForValue()
417   // Creates a new bucket to store `value` and inserts it at `index`.
418   // If the `index` is past the end, the bucket is inserted at the end of the
422     Bucket bucket = {1ULL << ComputeBucketOffset(value), bucket_start};  in InsertBucketFor()  local
423     auto it = buckets_.emplace(buckets_.begin() + index, std::move(bucket));  in InsertBucketFor()
433   // Returns true if the bucket at `bucketIndex/ stores the enum at
459   std::vector<Bucket> buckets_;