Add msgpack wire protocol with halfsiphash checksums

lib/msgpack/decode_typgen.go

@@ -0,0 +1,46 @@
+package msgpack
+
+import (
+	"reflect"
+	"sync"
+)
+
+var cachedValues struct {
+	m map[reflect.Type]chan reflect.Value
+	sync.RWMutex
+}
+
+func cachedValue(t reflect.Type) reflect.Value {
+	cachedValues.RLock()
+	ch := cachedValues.m[t]
+	cachedValues.RUnlock()
+	if ch != nil {
+		return <-ch
+	}
+
+	cachedValues.Lock()
+	defer cachedValues.Unlock()
+	if ch = cachedValues.m[t]; ch != nil {
+		return <-ch
+	}
+
+	ch = make(chan reflect.Value, 256)
+	go func() {
+		for {
+			ch <- reflect.New(t)
+		}
+	}()
+	if cachedValues.m == nil {
+		cachedValues.m = make(map[reflect.Type]chan reflect.Value, 8)
+	}
+	cachedValues.m[t] = ch
+	return <-ch
+}
+
+func (d *Decoder) newValue(t reflect.Type) reflect.Value {
+	if d.flags&usePreallocateValues == 0 {
+		return reflect.New(t)
+	}
+
+	return cachedValue(t)
+}