internal/cache: add (and move clock to internal/cache/clock)

1 files changed, 0 insertions, 86 deletions

diff --git a/internal/clock/cache.go b/internal/clock/cache.go
deleted file mode 100644
index 31d97082..00000000
--- a/internal/clock/cache.go
+++ /dev/null
@@ -1,86 +0,0 @@
-package clock
-
-import (
-	"hash/maphash"
-	"runtime"
-
-	"lindenii.org/go/lgo/intconv"
-)
-
-// maxShards bounds the shard count.
-//
-// Keep it relatively modest
-// so the per-shard budget
-// stays large enough to admit sizable values.
-const maxShards = 16
-
-// WeightFunc reports one entry's weight, used for eviction budgeting.
-type WeightFunc[K comparable, V any] func(key K, value V) uint64
-
-// Cache is a concurrent, weight-bounded cache
-// with CLOCK eviction.
-//
-// Reads are lock-free;
-// writes lock only the shard that owns the key.
-//
-// Labels: MT-Safe.
-type Cache[K comparable, V any] struct {
-	shards   []*shard[K, V]
-	seed     maphash.Seed
-	mask     uint64
-	weightFn WeightFunc[K, V]
-}
-
-// New returns a cache bounded to maxWeight total weight,
-// weighing entries with weightFn.
-//
-// New panics if weightFn is nil.
-func New[K comparable, V any](maxWeight uint64, weightFn WeightFunc[K, V]) *Cache[K, V] {
-	if weightFn == nil {
-		panic("internal/clock: nil weight function")
-	}
-
-	count, mask := shardLayout(maxWeight)
-	perShard := maxWeight / (mask + 1)
-
-	shards := make([]*shard[K, V], count)
-	for i := range shards {
-		shards[i] = newShard[K, V](perShard)
-	}
-
-	return &Cache[K, V]{
-		shards:   shards,
-		seed:     maphash.MakeSeed(),
-		mask:     mask,
-		weightFn: weightFn,
-	}
-}
-
-// shardLayout picks a power-of-two shard count and its address mask.
-//
-// Tracks GOMAXPROCS, capped at maxShards,
-// and is shrunk so the per-shard budget
-// stays at least one while maxWeight is nonzero.
-func shardLayout(maxWeight uint64) (int, uint64) {
-	count := 1
-	for count < runtime.GOMAXPROCS(0) && count < maxShards {
-		count *= 2
-	}
-
-	countU, err := intconv.IntToUint64(count)
-	if err != nil {
-		return 1, 0
-	}
-
-	for countU > maxWeight && countU > 1 {
-		count /= 2
-		countU /= 2
-	}
-
-	return count, countU - 1
-}
-
-// shardFor returns the shard that owns key.
-func (cache *Cache[K, V]) shardFor(key K) *shard[K, V] {
-	return cache.shards[maphash.Comparable(cache.seed, key)&cache.mask]
-}