5 Commits

Author SHA1 Message Date
2fc74169d5 Merge remote-tracking branch 'origin' into fix/infinite-put-glitch
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2026-03-24 21:24:48 -04:00
a815b49b66 docs: information about recommended minimum load
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2026-03-24 20:59:04 -04:00
b499fa9c05 fix: reduce minimum load in tests to <20% 2026-03-24 20:26:20 -04:00
9e936ebadb fix: prevent users from settings a growthfactor=1
- This always causes errors, it should not be possible.
2026-03-21 13:13:51 -04:00
d07f76207b feat: add options to fuzz testing
- Added the options to `fuzzScenario`.
- They are clamped to non-panic values, so it only tests viable combinations.
2026-03-21 13:07:11 -04:00
2 changed files with 48 additions and 7 deletions

View File

@@ -1,7 +1,10 @@
package cuckoo_test
import (
"fmt"
"maps"
"math"
"os"
"testing"
"github.com/stretchr/testify/assert"
@@ -26,6 +29,8 @@ type fuzzStep struct {
type fuzzScenario struct {
seedA, seedB uint32
capacity, growthFactor uint8
load float64
steps []fuzzStep
}
@@ -40,14 +45,33 @@ func FuzzInsertLookup(f *testing.F) {
return
}
if scenario.seedA == scenario.seedB {
return
seedA, seedB := scenario.seedA, scenario.seedB
growthFactor := max(2, int(scenario.growthFactor))
capacity := int(scenario.capacity)
minimumLoad := math.Abs(math.Mod(scenario.load, 1.0))
// If they are the same number, the hashes will clash, always causing an
// error.
if seedA == seedB {
t.Skip()
}
// If the load is too high, the hashs will not be able to allocate
// properly.
if minimumLoad > 0.20 {
t.Skip()
}
fmt.Fprintf(os.Stderr, "seedA=%d seedB=%d capacity=%d growthFactor=%d minimumLoad=%f\n",
seedA, seedB, capacity, growthFactor, minimumLoad)
actual := cuckoo.NewCustomTable[uint32, uint32](
offsetHash(scenario.seedA),
offsetHash(scenario.seedB),
offsetHash(seedA),
offsetHash(seedB),
func(a, b uint32) bool { return a == b },
cuckoo.Capacity(capacity),
cuckoo.GrowthFactor(growthFactor),
cuckoo.MinimumLoad(minimumLoad),
)
expected := map[uint32]uint32{}

View File

@@ -1,5 +1,7 @@
package cuckoo
import "fmt"
// DefaultCapacity is the initial capacity of a [Table]. It is inspired from
// Java's [HashMap] implementation, which also uses 16.
//
@@ -27,19 +29,34 @@ type settings struct {
type Option func(*settings)
// Capacity modifies the starting capacity of each bucket of the [Table]. The
// value must be greater than 0.
// value must be non-negative.
func Capacity(value int) Option {
if value < 0 {
panic(fmt.Sprintf("go-cuckoo: Capacity must be non-negative, got %d", value))
}
return func(s *settings) { s.bucketSize = uint64(value) }
}
// MinimumLoad modifies the [DefaultMinimumLoad] of the [Table]. The value must
// be between 0.00 and 1.00.
//
// The higher the minimum load, the more likely that a [Table.Put] will not
// succeed. Minimum loads above 20% are not tested.
func MinimumLoad(value float64) Option {
if value < 0.00 || value > 1.00 {
panic(fmt.Sprintf("go-cuckoo: MinimumLoad must be between 0.00 and 1.00, got %f", value))
}
return func(s *settings) { s.minLoadFactor = value }
}
// GrowthFactor controls how much the capacity of the [Table] multiplies when
// it must resize. The value must be greater than 1.
func GrowthFactor(value int) Option {
if value < 2 {
panic(fmt.Sprintf("go-cuckoo: GrowthFactor must be greater than 1, got %d", value))
}
return func(s *settings) { s.growthFactor = uint64(value) }
}