improve hashing and avoid dedicated MapString type

Makefile

@@ -23,11 +23,3 @@ test-coverage-web: test-coverage ## run unit tests and show test coverage in bro
 
 install-linters: ## install all used linters
 	curl -sSfL https://raw.githubusercontent.com/golangci/golangci-lint/master/install.sh | sh -s -- -b $$(go env GOPATH)/bin v1.49.0
-
-alternatives: ## generate alternative non numeric hashmap versions
-	cp hashmap.go hashmap_string.go
-	sed -i 's,Map,MapString,' hashmap_string.go
-	sed -i 's,New\[,NewString\[,' hashmap_string.go
-	sed -i 's,// New,// NewString,' hashmap_string.go
-	sed -i 's,NewSized,NewStringSized,' hashmap_string.go
-	sed -i 's,numeric,string,' hashmap_string.go

README.md

@@ -15,8 +15,6 @@ The minimal supported Golang version is 1.19 as it makes use of Generics and the
 
 ## Usage
 
-For `New()` only Go numeric types are supported. For string keyed maps `NewString` has to be used.
-
 Example uint8 key map uses:
 
 ```
@@ -28,14 +26,14 @@ value, ok := m.Get(1)
 Example string key map uses:
 
 ```
-m := NewString[string, int]()
+m := New[string, int]()
 m.Set("amount", 123)
 value, ok := m.Get("amount")
 ```
 
 Using the map to count URL requests:
 ```
-m := NewString[string, *int64]()
+m := New[string, *int64]()
 var i int64
 counter, _ := m.GetOrInsert("api/123", &i)
 atomic.AddInt64(counter, 1) // increase counter
@@ -49,18 +47,18 @@ Reading from the hash map for numeric key types in a thread-safe way is faster t
 in an unsafe way and four times faster than Golang's `sync.Map`:
 
 ```
-BenchmarkReadHashMapUint-8                	 1788601	       668.4 ns/op
-BenchmarkReadHaxMapUint-8                 	 1691654	       709.6 ns/op
-BenchmarkReadGoMapUintUnsafe-8            	 1516452	       784.4 ns/op
-BenchmarkReadGoMapUintMutex-8             	   39429	     27978 ns/op
-BenchmarkReadGoSyncMapUint-8              	  446930	      2544 ns/op
+BenchmarkReadHashMapUint-8                	 1774460	       677.3 ns/op
+BenchmarkReadHaxMapUint-8                 	 1758708	       679.0 ns/op
+BenchmarkReadGoMapUintUnsafe-8            	 1497732	       790.9 ns/op
+BenchmarkReadGoMapUintMutex-8             	   41562	     28672 ns/op
+BenchmarkReadGoSyncMapUint-8              	  454401	      2646 ns/op
 ```
 
 Reading from the map while writes are happening:
 ```
-BenchmarkReadHashMapWithWritesUint-8      	 1418299	       856.4 ns/op
-BenchmarkReadHaxMapWithWritesUint-8       	 1262414	       948.5 ns/op
-BenchmarkReadGoSyncMapWithWritesUint-8    	  382785	      3240 ns/op
+BenchmarkReadHashMapWithWritesUint-8      	 1388560	       859.1 ns/op
+BenchmarkReadHaxMapWithWritesUint-8       	 1306671	       914.5 ns/op
+BenchmarkReadGoSyncMapWithWritesUint-8    	  335732	      3113 ns/op
 ```
 
 Write performance without any concurrent reads:
@@ -88,5 +86,3 @@ The benchmarks were run with Golang 1.19.0 on Linux and AMD64 using `make benchm
   When the slice reaches a defined fill rate, a bigger slice is allocated and all keys are recalculated and transferred into the new slice.
 
 * For hashing, specialized xxhash implementations are used that match the size of the key type where available
-
-* A specialized String version of the map exists due to a limitation of type switches of parametric types - see https://github.com/golang/go/issues/45380 for more info.

benchmarks/benchmark_test.go

@@ -32,10 +32,10 @@ func setupHaxMap(b *testing.B) *haxmap.HashMap[uintptr, uintptr] {
 	return m
 }
 
-func setupHashMapString(b *testing.B) (*hashmap.MapString[string, string], []string) {
+func setupHashMapString(b *testing.B) (*hashmap.Map[string, string], []string) {
 	b.Helper()
 
-	m := hashmap.NewString[string, string]()
+	m := hashmap.New[string, string]()
 	keys := make([]string, benchmarkItemCount)
 	for i := 0; i < benchmarkItemCount; i++ {
 		s := strconv.Itoa(i)

benchmarks/go.mod

@@ -5,6 +5,6 @@ go 1.19
 replace github.com/cornelk/hashmap => ../
 
 require (
-	github.com/alphadose/haxmap v0.3.1-0.20220831135524-f7fd3700af2e
+	github.com/alphadose/haxmap v0.3.1
 	github.com/cornelk/hashmap v1.0.7-0.20220831150614-2c244e4098a0
 )

benchmarks/go.sum

@@ -2,3 +2,5 @@ github.com/alphadose/haxmap v0.3.1-0.20220831034947-0d601bb44159 h1:Vy5DvT2YgH2N
 github.com/alphadose/haxmap v0.3.1-0.20220831034947-0d601bb44159/go.mod h1:Fu37Wlmj7cR++vSLgRTu3fGy8wpjHGmMypM2aclkc1A=
 github.com/alphadose/haxmap v0.3.1-0.20220831135524-f7fd3700af2e h1:wNcWJlc0StruM5i6yPyrDYQDO3pxrxm1b/U2boezeVI=
 github.com/alphadose/haxmap v0.3.1-0.20220831135524-f7fd3700af2e/go.mod h1:Fu37Wlmj7cR++vSLgRTu3fGy8wpjHGmMypM2aclkc1A=
+github.com/alphadose/haxmap v0.3.1 h1:P02INS0xIwY0R3E+KRJTPtrlwTvRPYoU2GgoeRk2KbU=
+github.com/alphadose/haxmap v0.3.1/go.mod h1:Fu37Wlmj7cR++vSLgRTu3fGy8wpjHGmMypM2aclkc1A=

defines.go

@@ -6,7 +6,7 @@ const defaultSize = 8
 // maxFillRate is the maximum fill rate for the slice before a resize will happen.
 const maxFillRate = 50
 
-// support all numeric types and types whose underlying type is also numeric.
-type numeric interface {
-	~int | ~int8 | ~int16 | ~int32 | ~int64 | ~uint | ~uint8 | ~uint16 | ~uint32 | ~uint64 | ~uintptr | ~float32 | ~float64
+// support all numeric and string types and aliases of those.
+type hashable interface {
+	~int | ~int8 | ~int16 | ~int32 | ~int64 | ~uint | ~uint8 | ~uint16 | ~uint32 | ~uint64 | ~uintptr | ~float32 | ~float64 | ~string
 }

example_test.go

@@ -11,7 +11,7 @@ import (
 // TestAPICounter shows how to use the hashmap to count REST server API calls.
 func TestAPICounter(t *testing.T) {
 	t.Parallel()
-	m := NewString[string, *int64]()
+	m := New[string, *int64]()
 
 	for i := 0; i < 100; i++ {
 		s := fmt.Sprintf("/api%d/", i%4)
@@ -28,7 +28,7 @@ func TestAPICounter(t *testing.T) {
 }
 
 func TestExample(t *testing.T) {
-	m := NewString[string, int]()
+	m := New[string, int]()
 	m.Set("amount", 123)
 	value, ok := m.Get("amount")
 	assert.True(t, ok)

hashmap.go

@@ -11,7 +11,7 @@ import (
 )
 
 // Map implements a read optimized hash map.
-type Map[Key numeric, Value any] struct {
+type Map[Key hashable, Value any] struct {
 	hasher     func(Key) uintptr
 	store      atomic.Pointer[store[Key, Value]] // pointer to a map instance that gets replaced if the map resizes
 	linkedList *List[Key, Value]                 // key sorted linked list of elements
@@ -21,12 +21,12 @@ type Map[Key numeric, Value any] struct {
 }
 
 // New returns a new map instance.
-func New[Key numeric, Value any]() *Map[Key, Value] {
+func New[Key hashable, Value any]() *Map[Key, Value] {
 	return NewSized[Key, Value](defaultSize)
 }
 
 // NewSized returns a new map instance with a specific initialization size.
-func NewSized[Key numeric, Value any](size uintptr) *Map[Key, Value] {
+func NewSized[Key hashable, Value any](size uintptr) *Map[Key, Value] {
 	m := &Map[Key, Value]{}
 	m.allocate(size)
 	m.setDefaultHasher()