fix: Table.Drop() was not a pointer receiver

- Generalized Table.resize() to accept a capacity size for each bucket.

.gremlins.yaml

@@ -5,5 +5,3 @@ unleash:
   
   workers: 4
   dry-run: false
-  threshold:
-    efficacy: 1.0

Makefile

@@ -16,12 +16,10 @@ test-unit: ## Run unit tests with coverage
 test-mutation: ## Run mutation tests with gremlins
 	gremlins unleash
 
-FUZZ_TIME ?= 30
-
 test-fuzz: ## Run all fuzz tests for 30s each
 	@for func in $$(grep -r --include='*_test.go' -oh 'func Fuzz\w*' . | sed 's/func //'); do \
 		echo "Fuzzing $$func..."; \
-		go test ./... -fuzz="^$$func$$" -fuzztime=$(FUZZ_TIME)s; \
+		go test ./... -fuzz="^$$func$$" -fuzztime=30s; \
 	done
 
 test: test-unit test-mutation test-fuzz ## Run all tests

bucket.go

@@ -17,26 +17,16 @@ type bucket[K, V any] struct {
 	compare        EqualFunc[K]
 }
 
-// location determines where in the bucket a certain key would be placed. If the
-// capacity is 0, this will panic.
 func (b bucket[K, V]) location(key K) uint64 {
 	return b.hash(key) % b.capacity
 }
 
 func (b bucket[K, V]) get(key K) (value V, found bool) {
-	if b.capacity == 0 {
-		return
-	}
-
 	slot := b.slots[b.location(key)]
 	return slot.value, slot.occupied && b.compare(slot.key, key)
 }
 
 func (b *bucket[K, V]) drop(key K) (occupied bool) {
-	if b.capacity == 0 {
-		return
-	}
-
 	slot := &b.slots[b.location(key)]
 
 	if slot.occupied && b.compare(slot.key, key) {
@@ -55,10 +45,6 @@ func (b *bucket[K, V]) resize(capacity uint64) {
 }
 
 func (b bucket[K, V]) update(key K, value V) (updated bool) {
-	if b.capacity == 0 {
-		return
-	}
-
 	slot := &b.slots[b.location(key)]
 
 	if slot.occupied && b.compare(slot.key, key) {
@@ -70,10 +56,6 @@ func (b bucket[K, V]) update(key K, value V) (updated bool) {
 }
 
 func (b *bucket[K, V]) evict(insertion entry[K, V]) (evicted entry[K, V], eviction bool) {
-	if b.capacity == 0 {
-		return insertion, true
-	}
-
 	slot := &b.slots[b.location(insertion.key)]
 
 	if !slot.occupied {

cuckoo_fuzz_test.go

@@ -1,11 +1,11 @@
 package cuckoo_test
 
 import (
-	"maps"
+	"bytes"
+	"encoding/binary"
 	"testing"
 
 	"github.com/stretchr/testify/assert"
-	go_fuzz_utils "github.com/trailofbits/go-fuzz-utils"
 
 	"git.maximhutz.com/tools/go-cuckoo"
 )
@@ -19,60 +19,31 @@ func offsetHash(seed uint32) cuckoo.Hash[uint32] {
 	}
 }
 
-type fuzzStep struct {
-	drop       bool
-	key, value uint32
-}
-
-type fuzzScenario struct {
-	seedA, seedB uint32
-	steps        []fuzzStep
-}
-
 func FuzzInsertLookup(f *testing.F) {
-	f.Fuzz(func(t *testing.T, data []byte) {
+	f.Fuzz(func(t *testing.T, data []byte, seedA, seedB uint32) {
-		var scenario fuzzScenario
 		assert := assert.New(t)
 
-		if tp, err := go_fuzz_utils.NewTypeProvider(data); err != nil {
+		table := cuckoo.NewCustomTable[uint32, uint32](
-			return
+			offsetHash(seedA),
-		} else if err := tp.Fill(&scenario); err != nil {
+			offsetHash(seedB),
-			return
-		}
-
-		if scenario.seedA == scenario.seedB {
-			return
-		}
-
-		actual := cuckoo.NewCustomTable[uint32, uint32](
-			offsetHash(scenario.seedA),
-			offsetHash(scenario.seedB),
 			func(a, b uint32) bool { return a == b },
 		)
 
-		expected := map[uint32]uint32{}
+		if seedA == seedB {
-
+			return
-		for _, step := range scenario.steps {
-			if step.drop {
-				err := actual.Drop(step.key)
-				assert.NoError(err)
-
-				delete(expected, step.key)
-
-				_, err = actual.Get(step.key)
-				assert.Error(err)
-			} else {
-				err := actual.Put(step.key, step.value)
-				assert.NoError(err)
-
-				expected[step.key] = step.value
-
-				found, err := actual.Get(step.key)
-				assert.NoError(err)
-				assert.Equal(step.value, found)
 		}
 
-			assert.Equal(expected, maps.Collect(actual.Entries()))
+		r := bytes.NewReader(data)
+		var key, value uint32
+		for binary.Read(r, binary.LittleEndian, &key) == nil &&
+			binary.Read(r, binary.LittleEndian, &value) == nil {
+
+			err := table.Put(key, value)
+			assert.NoError(err)
+
+			found, err := table.Get(key)
+			assert.NoError(err)
+			assert.Equal(value, found)
 		}
 	})
 }

cuckoo_test.go

@@ -1,7 +1,6 @@
 package cuckoo_test
 
 import (
-	"errors"
 	"maps"
 	"math/rand/v2"
 	"testing"
@@ -130,7 +129,7 @@ func TestRemove(t *testing.T) {
 	assert.True(table.Has(0))
 }
 
-func TestDropExistingItem(t *testing.T) {
+func TestDropItem(t *testing.T) {
 	assert := assert.New(t)
 	key, value := 0, true
 	table := cuckoo.NewTable[int, bool]()
@@ -142,100 +141,3 @@ func TestDropExistingItem(t *testing.T) {
 	assert.Equal(0, table.Size())
 	assert.False(table.Has(key))
 }
-
-func TestDropNoItem(t *testing.T) {
-	assert := assert.New(t)
-	key := 0
-	table := cuckoo.NewTable[int, bool]()
-
-	err := table.Drop(key)
-
-	assert.NoError(err)
-	assert.Equal(0, table.Size())
-	assert.False(table.Has(key))
-}
-
-func TestDropItemCapacity(t *testing.T) {
-	assert := assert.New(t)
-	key := 0
-	table := cuckoo.NewTable[int, bool](
-		cuckoo.Capacity(64),
-		cuckoo.GrowthFactor(2),
-	)
-
-	startingCapacity := table.TotalCapacity()
-	err := table.Drop(key)
-	endingCapacity := table.TotalCapacity()
-
-	assert.NoError(err)
-	assert.Equal(0, table.Size())
-	assert.Equal(uint64(128), startingCapacity)
-	assert.Equal(uint64(64), endingCapacity)
-}
-
-func TestPutNoCapacity(t *testing.T) {
-	assert := assert.New(t)
-	key, value := 0, true
-	table := cuckoo.NewTable[int, bool](
-		cuckoo.Capacity(0),
-	)
-
-	err := table.Put(key, value)
-
-	assert.NoError(err)
-	assert.Equal(1, table.Size())
-	assert.True(table.Has(key))
-}
-
-func TestBadHashCapacity(t *testing.T) {
-	assert := assert.New(t)
-	table := cuckoo.NewCustomTable[int, bool](
-		func(int) uint64 { return 0 },
-		func(int) uint64 { return 0 },
-		func(a, b int) bool { return a == b },
-		cuckoo.Capacity(20),
-	)
-
-	err1 := table.Put(0, true)
-	err2 := table.Put(1, true)
-	err3 := table.Put(2, true)
-
-	assert.NoError(err1)
-	assert.NoError(err2)
-	assert.Error(err3)
-
-	assert.Equal(uint64(80), table.TotalCapacity())
-}
-
-func TestDropResizeCapacity(t *testing.T) {
-	assert := assert.New(t)
-	table := cuckoo.NewTable[int, bool](
-		cuckoo.Capacity(10),
-	)
-
-	err1 := table.Put(0, true)
-	err2 := table.Put(1, true)
-	err3 := table.Drop(1)
-
-	assert.NoError(errors.Join(err1, err2, err3))
-	assert.Equal(uint64(20), table.TotalCapacity())
-}
-
-func TestNewTableBy(t *testing.T) {
-	type User struct {
-		_    func()
-		id   string
-		name string
-	}
-
-	assert := assert.New(t)
-	table := cuckoo.NewTableBy[User, bool](
-		func(u User) string { return u.id },
-	)
-
-	err := table.Put(User{nil, "1", "Robert"}, true)
-
-	assert.NoError(err)
-	assert.Equal(1, table.Size())
-	assert.True(table.Has(User{nil, "1", "Robbie"}))
-}

go.mod

@@ -4,11 +4,8 @@ go 1.25.6
 
 require github.com/stretchr/testify v1.11.1
 
-require github.com/kr/pretty v0.3.1 // indirect
-
 require (
 	github.com/davecgh/go-spew v1.1.1 // indirect
 	github.com/pmezard/go-difflib v1.0.0 // indirect
-	github.com/trailofbits/go-fuzz-utils v0.0.0-20260318143407-0907cafe7589
 	gopkg.in/yaml.v3 v3.0.1 // indirect
 )

go.sum

@@ -1,21 +1,10 @@
-github.com/creack/pty v1.1.9/go.mod h1:oKZEueFk5CKHvIhNR5MUki03XCEU+Q6VDXinZuGJ33E=
 github.com/davecgh/go-spew v1.1.1 h1:vj9j/u1bqnvCEfJOwUhtlOARqs3+rkHYY13jYWTU97c=
 github.com/davecgh/go-spew v1.1.1/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
-github.com/kr/pretty v0.3.1 h1:flRD4NNwYAUpkphVc1HcthR4KEIFJ65n8Mw5qdRn3LE=
-github.com/kr/pretty v0.3.1/go.mod h1:hoEshYVHaxMs3cyo3Yncou5ZscifuDolrwPKZanG3xk=
-github.com/kr/text v0.2.0 h1:5Nx0Ya0ZqY2ygV366QzturHI13Jq95ApcVaJBhpS+AY=
-github.com/kr/text v0.2.0/go.mod h1:eLer722TekiGuMkidMxC/pM04lWEeraHUUmBw8l2grE=
-github.com/pkg/diff v0.0.0-20210226163009-20ebb0f2a09e/go.mod h1:pJLUxLENpZxwdsKMEsNbx1VGcRFpLqf3715MtcvvzbA=
 github.com/pmezard/go-difflib v1.0.0 h1:4DBwDE0NGyQoBHbLQYPwSUPoCMWR5BEzIk/f1lZbAQM=
 github.com/pmezard/go-difflib v1.0.0/go.mod h1:iKH77koFhYxTK1pcRnkKkqfTogsbg7gZNVY4sRDYZ/4=
-github.com/rogpeppe/go-internal v1.9.0 h1:73kH8U+JUqXU8lRuOHeVHaa/SZPifC7BkcraZVejAe8=
-github.com/rogpeppe/go-internal v1.9.0/go.mod h1:WtVeX8xhTBvf0smdhujwtBcq4Qrzq/fJaraNFVN+nFs=
 github.com/stretchr/testify v1.11.1 h1:7s2iGBzp5EwR7/aIZr8ao5+dra3wiQyKjjFuvgVKu7U=
 github.com/stretchr/testify v1.11.1/go.mod h1:wZwfW3scLgRK+23gO65QZefKpKQRnfz6sD981Nm4B6U=
-github.com/trailofbits/go-fuzz-utils v0.0.0-20260318143407-0907cafe7589 h1:UmBZCTPdDYore2IEHN+U4eIqEaRq6METh9pKiPumkqc=
+gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405 h1:yhCVgyC4o1eVCa2tZl7eS0r+SDo693bJlVdllGtEeKM=
-github.com/trailofbits/go-fuzz-utils v0.0.0-20260318143407-0907cafe7589/go.mod h1:zh+T+w9XT/3o4E0WLEGCdmLJ8Yqx/zY3o538tQY3OjY=
 gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0=
-gopkg.in/check.v1 v1.0.0-20201130134442-10cb98267c6c h1:Hei/4ADfdWqJk1ZMxUNpqntNwaWcugrBjAiHlqqRiVk=
-gopkg.in/check.v1 v1.0.0-20201130134442-10cb98267c6c/go.mod h1:JHkPIbrfpd72SG/EVd6muEfDQjcINNoR0C8j2r3qZ4Q=
 gopkg.in/yaml.v3 v3.0.1 h1:fxVm/GzAzEWqLHuvctI91KS9hhNmmWOoWu0XTYJS7CA=
 gopkg.in/yaml.v3 v3.0.1/go.mod h1:K4uyk7z7BCEPqu6E+C64Yfv1cQ7kz7rIZviUmN+EgEM=

table.go

@@ -28,7 +28,7 @@ func (t Table[K, V]) Size() int {
 }
 
 func log2(n uint64) (m int) {
-	return max(0, bits.Len64(n)-1)
+	return bits.Len64(n) - 1
 }
 
 func (t Table[K, V]) maxEvictions() int {
@@ -36,18 +36,9 @@ func (t Table[K, V]) maxEvictions() int {
 }
 
 func (t Table[K, V]) load() float64 {
-	// When there are no slots in the table, we still treat the load as 100%.
-	// Every slot in the table is full.
-	if t.TotalCapacity() == 0 {
-		return 1.0
-	}
-
 	return float64(t.Size()) / float64(t.TotalCapacity())
 }
 
-// resize clears all buckets, changes the sizes of them to a specific capacity,
-// and fills them back up again. It is a helper function for [Table.grow] and
-// [Table.shrink]; use them instead.
 func (t *Table[K, V]) resize(capacity uint64) error {
 	entries := make([]entry[K, V], 0, t.Size())
 	for k, v := range t.Entries() {
@@ -66,26 +57,6 @@ func (t *Table[K, V]) resize(capacity uint64) error {
 	return nil
 }
 
-// grow increases the table's capacity by the [Table.growthFactor]. If the
-// capacity is 0, it increases it to 1.
-func (t *Table[K, V]) grow() error {
-	var newCapacity uint64
-
-	if t.TotalCapacity() == 0 {
-		newCapacity = 1
-	} else {
-		newCapacity = t.bucketA.capacity * t.growthFactor
-	}
-
-	return t.resize(newCapacity)
-}
-
-// shrink reduces the table's capacity by the [Table.growthFactor]. It may
-// reduce it down to 0.
-func (t *Table[K, V]) shrink() error {
-	return t.resize(t.bucketA.capacity / t.growthFactor)
-}
-
 // Get fetches the value for a key in the [Table]. Returns an error if no value
 // is found.
 func (t Table[K, V]) Get(key K) (value V, err error) {
@@ -131,7 +102,7 @@ func (t *Table[K, V]) Put(key K, value V) (err error) {
 		return fmt.Errorf("bad hash: resize on load %d/%d = %f", t.Size(), t.TotalCapacity(), t.load())
 	}
 
-	if err := t.grow(); err != nil {
+	if err := t.resize(t.growthFactor * t.bucketA.capacity); err != nil {
 		return err
 	}
 
@@ -145,7 +116,7 @@ func (t *Table[K, V]) Drop(key K) (err error) {
 	t.bucketB.drop(key)
 
 	if t.load() < t.minLoadFactor {
-		return t.shrink()
+		return t.resize(t.bucketA.capacity / t.growthFactor)
 	}
 
 	return nil