diff options
Diffstat (limited to 'absl/container/internal/raw_hash_set.h')
| -rw-r--r-- | absl/container/internal/raw_hash_set.h | 14 |
1 files changed, 11 insertions, 3 deletions
diff --git a/absl/container/internal/raw_hash_set.h b/absl/container/internal/raw_hash_set.h index 74b2ef4c..80fc2cba 100644 --- a/absl/container/internal/raw_hash_set.h +++ b/absl/container/internal/raw_hash_set.h @@ -468,8 +468,16 @@ inline size_t NormalizeCapacity(size_t n) { return n ? ~size_t{} >> countl_zero(n) : 1; } -// We use 7/8th as maximum load factor. -// For 16-wide groups, that gives an average of two empty slots per group. +// General notes on capacity/growth methods below: +// - We use 7/8th as maximum load factor. For 16-wide groups, that gives an +// average of two empty slots per group. +// - For (capacity+1) >= Group::kWidth, growth is 7/8*capacity. +// - For (capacity+1) < Group::kWidth, growth == capacity. In this case, we +// never need to probe (the whole table fits in one group) so we don't need a +// load factor less than 1. + +// Given `capacity` of the table, returns the size (i.e. number of full slots) +// at which we should grow the capacity. inline size_t CapacityToGrowth(size_t capacity) { assert(IsValidCapacity(capacity)); // `capacity*7/8` @@ -480,7 +488,7 @@ inline size_t CapacityToGrowth(size_t capacity) { return capacity - capacity / 8; } // From desired "growth" to a lowerbound of the necessary capacity. -// Might not be a valid one and required NormalizeCapacity(). +// Might not be a valid one and requires NormalizeCapacity(). inline size_t GrowthToLowerboundCapacity(size_t growth) { // `growth*8/7` if (Group::kWidth == 8 && growth == 7) { |