add hmap.Iterate()

README.md

@@ -79,13 +79,13 @@ The default bucket size is 24 if a BucketSizeOption is not set.
 ### for k, v := range
 Since this is a concurrent hashmap, you'll need to call `Lock()` before doing a
 range operation. And remember to call `Unlock()` afterwards.
-```
+```go
 func rangeMap(m HashMap) error {
-    f := func(interface{}, interface{}) error {
-        // define what to do for each entry in the map
-        return
-    }
-    
+	f := func(interface{}, interface{}) error {
+		// define what to do for each entry in the map
+		return
+	}
+
 	m.Lock()
 	for k, v, ok := m.Next(); ok; k, v, ok = m.Next() {
 	    if err := f(k, v); err != nil {
@@ -98,6 +98,16 @@ func rangeMap(m HashMap) error {
 	return nil
 }
 ```
+A shortcut:
+```go
+m.Iterate(func(_k interface{}, _v interface{}) error {
+	k := _k.(string)
+	v := _v.(int64)
+	// do something
+	return nil
+})
+```
+
 ## Queue
 - FIFO list that can be concurrently accessed
 - can put different data types into the queue

hashmap/hmap.go

@@ -147,6 +147,17 @@ func (h *hmap) Next() (interface{}, interface{}, bool) {
 
 }
 
+func (h *hmap) Iterate(f func(_k interface{}, _v interface{}) error) error {
+	h.Lock()
+	defer h.Unlock() // unlock even panic
+	for k, v, ok := h.Next(); ok; k, v, ok = h.Next() {
+		if err := f(k, v); err != nil {
+			return err
+		}
+	}
+	return nil
+}
+
 func (h *hmap) getBucket(hash uint64) *bucket {
 	h.mutex.RLock()
 	b := h.buckets[hash>>(64-h.B)]

hashmap/hmap_test.go

@@ -97,4 +97,28 @@ func TestHmap(t *testing.T) {
 	req.Equal(len(tests)-1, match)
 	req.Equal(10000+len(tests)-1, total)
 	m.info()
+
+	// test Iterate()
+	total = 0
+	match = 0
+	err := m.Iterate(func(k interface{}, v interface{}) error {
+		for i := range tests {
+			if k == tests[i].k {
+				req.Equal(tests[i].v, v)
+				match++
+			}
+		}
+		total++
+		return nil
+	})
+	req.Nil(err)
+
+	k, v, ok = m.Next()
+	req.False(ok)
+	req.Nil(k)
+	req.Nil(v)
+	m.Unlock()
+	req.Equal(len(tests)-1, match)
+	req.Equal(10000+len(tests)-1, total)
+	m.info()
 }

map.go

@@ -41,6 +41,9 @@ type (
 
 		// returns next <k, v> in the map
 		Next() (interface{}, interface{}, bool)
+
+		// iterate over all element
+		Iterate(func(_k interface{}, _v interface{}) error) error
 	}
 )