fix #91

@@ -8,6 +8,8 @@ type Cache interface {
 	Get(key string) interface{}
 	Put(key string, val interface{}, timeout int64) error
 	Delete(key string) error
+	Incr(key string) error
+	Decr(key string) error
 	IsExist(key string) bool
 	ClearAll() error
 	StartAndGC(config string) error

@@ -31,6 +31,21 @@ func Test_cache(t *testing.T) {
 		t.Error("set Error", err)
 	}
 
+	if err = bm.Incr("astaxie"); err != nil {
+		t.Error("Incr Error", err)
+	}
+
+	if v := bm.Get("astaxie"); v.(int) != 2 {
+		t.Error("get err")
+	}
+
+	if err = bm.Decr("astaxie"); err != nil {
+		t.Error("Incr Error", err)
+	}
+
+	if v := bm.Get("astaxie"); v.(int) != 1 {
+		t.Error("get err")
+	}
 	bm.Delete("astaxie")
 	if bm.IsExist("astaxie") {
 		t.Error("delete err")

@@ -51,6 +51,14 @@ func (rc *MemcacheCache) Delete(key string) error {
 	return err
 }
 
+func (rc *MemcacheCache) Incr(key string) error {
+	return errors.New("not support in memcache")
+}
+
+func (rc *MemcacheCache) Decr(key string) error {
+	return errors.New("not support in memcache")
+}
+
 func (rc *MemcacheCache) IsExist(key string) bool {
 	if rc.c == nil {
 		rc.c = rc.connectInit()

@@ -75,6 +75,70 @@ func (bc *MemoryCache) Delete(name string) error {
 	return nil
 }
 
+func (bc *MemoryCache) Incr(key string) error {
+	bc.lock.RLock()
+	defer bc.lock.RUnlock()
+	itm, ok := bc.items[key]
+	if !ok {
+		return errors.New("key not exist")
+	}
+	switch itm.val.(type) {
+	case int:
+		itm.val = itm.val.(int) + 1
+	case int64:
+		itm.val = itm.val.(int64) + 1
+	case int32:
+		itm.val = itm.val.(int32) + 1
+	case uint:
+		itm.val = itm.val.(uint) + 1
+	case uint32:
+		itm.val = itm.val.(uint32) + 1
+	case uint64:
+		itm.val = itm.val.(uint64) + 1
+	default:
+		return errors.New("item val is not int int64 int32")
+	}
+	return nil
+}
+
+func (bc *MemoryCache) Decr(key string) error {
+	bc.lock.RLock()
+	defer bc.lock.RUnlock()
+	itm, ok := bc.items[key]
+	if !ok {
+		return errors.New("key not exist")
+	}
+	switch itm.val.(type) {
+	case int:
+		itm.val = itm.val.(int) - 1
+	case int64:
+		itm.val = itm.val.(int64) - 1
+	case int32:
+		itm.val = itm.val.(int32) - 1
+	case uint:
+		if itm.val.(uint) > 0 {
+			itm.val = itm.val.(uint) - 1
+		} else {
+			return errors.New("item val is less than 0")
+		}
+	case uint32:
+		if itm.val.(uint32) > 0 {
+			itm.val = itm.val.(uint32) - 1
+		} else {
+			return errors.New("item val is less than 0")
+		}
+	case uint64:
+		if itm.val.(uint64) > 0 {
+			itm.val = itm.val.(uint64) - 1
+		} else {
+			return errors.New("item val is less than 0")
+		}
+	default:
+		return errors.New("item val is not int int64 int32")
+	}
+	return nil
+}
+
 func (bc *MemoryCache) IsExist(name string) bool {
 	bc.lock.RLock()
 	defer bc.lock.RUnlock()

@@ -58,6 +58,28 @@ func (rc *RedisCache) IsExist(key string) bool {
 	return v
 }
 
+func (rc *RedisCache) Incr(key string) error {
+	if rc.c == nil {
+		rc.c = rc.connectInit()
+	}
+	_, err := redis.Bool(rc.c.Do("HINCRBY", rc.key, key, 1))
+	if err != nil {
+		return err
+	}
+	return nil
+}
+
+func (rc *RedisCache) Decr(key string) error {
+	if rc.c == nil {
+		rc.c = rc.connectInit()
+	}
+	_, err := redis.Bool(rc.c.Do("HINCRBY", rc.key, key, -1))
+	if err != nil {
+		return err
+	}
+	return nil
+}
+
 func (rc *RedisCache) ClearAll() error {
 	if rc.c == nil {
 		rc.c = rc.connectInit()