1 files changed, 20 insertions, 22 deletions
diff --git a/core/vm/errors.go b/core/vm/errors.go
index 799eb6797..d0c332068 100644
--- a/core/vm/errors.go
+++ b/core/vm/errors.go
@@ -1,21 +1,30 @@
+// Copyright 2014 The go-ethereum Authors
+// This file is part of go-ethereum.
+//
+// go-ethereum is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Lesser General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// go-ethereum is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU Lesser General Public License for more details.
+//
+// You should have received a copy of the GNU Lesser General Public License
+// along with go-ethereum.  If not, see <http://www.gnu.org/licenses/>.
+
 package vm
 
 import (
+	"errors"
 	"fmt"
 
 	"github.com/ethereum/go-ethereum/params"
 )
 
-type OutOfGasError struct{}
-
-func (self OutOfGasError) Error() string {
-	return "Out Of Gas"
-}
-
-func IsOOGErr(err error) bool {
-	_, ok := err.(OutOfGasError)
-	return ok
-}
+var OutOfGasError = errors.New("Out of gas")
+var DepthError = fmt.Errorf("Max call depth exceeded (%d)", params.CallCreateDepth)
 
 type StackError struct {
 	req, has int
@@ -29,18 +38,7 @@ func (self StackError) Error() string {
 	return fmt.Sprintf("stack error! require %v, have %v", self.req, self.has)
 }
 
-func IsStack(err error) bool {
+func IsStackErr(err error) bool {
 	_, ok := err.(StackError)
 	return ok
 }
-
-type DepthError struct{}
-
-func (self DepthError) Error() string {
-	return fmt.Sprintf("Max call depth exceeded (%d)", params.CallCreateDepth)
-}
-
-func IsDepthErr(err error) bool {
-	_, ok := err.(DepthError)
-	return ok
-}