added

vendor/github.com/glycerine/zygomys/zygo/ptrcheck.go

@@ -0,0 +1,59 @@
+package zygo
+
+import (
+	"reflect"
+)
+
+// true if target is type *T where T
+// is a struct/string/int/other-non-pointer type.
+func IsExactlySinglePointer(target interface{}) bool {
+	//	va, isVa := target.(reflect.Value)
+	//	if isVa {
+	//		return IsExactlySinglePointerType(va.Type())
+	//	}
+	typ := reflect.ValueOf(target).Type()
+	return IsExactlySinglePointerType(typ)
+}
+func IsExactlySinglePointerType(typ reflect.Type) bool {
+	kind := typ.Kind()
+	if kind != reflect.Ptr {
+		return false
+	}
+	typ2 := typ.Elem()
+	kind2 := typ2.Kind()
+	if kind2 == reflect.Ptr {
+		return false // two level pointer
+	}
+	return true
+}
+
+// true if target is of type **T where T is
+// a struct/string/int/other-non-pointer type.
+func IsExactlyDoublePointer(target interface{}) bool {
+	typ := reflect.ValueOf(target).Type()
+	kind := typ.Kind()
+	if kind != reflect.Ptr {
+		return false
+	}
+	typ2 := typ.Elem()
+	kind2 := typ2.Kind()
+	if kind2 != reflect.Ptr {
+		return false
+	}
+	if typ2.Elem().Kind() == reflect.Ptr {
+		return false // triple level pointer, not double.
+	}
+	return true
+}
+
+func PointerDepth(typ reflect.Type) int {
+	return pointerDepthHelper(typ, 0)
+}
+
+func pointerDepthHelper(typ reflect.Type, accum int) int {
+	kind := typ.Kind()
+	if kind != reflect.Ptr {
+		return accum
+	}
+	return pointerDepthHelper(typ.Elem(), accum+1)
+}