Merge eth-go repository into go-ethereum

mist, etheruem have been moved to cmd/

vm/environment.go

@@ -0,0 +1,46 @@
+package vm
+
+import (
+	"errors"
+	"math/big"
+
+	"github.com/ethereum/go-ethereum/ethstate"
+	"github.com/ethereum/go-ethereum/ethutil"
+)
+
+type Environment interface {
+	State() *ethstate.State
+
+	Origin() []byte
+	BlockNumber() *big.Int
+	PrevHash() []byte
+	Coinbase() []byte
+	Time() int64
+	Difficulty() *big.Int
+	BlockHash() []byte
+	GasLimit() *big.Int
+	Transfer(from, to Account, amount *big.Int) error
+}
+
+type Object interface {
+	GetStorage(key *big.Int) *ethutil.Value
+	SetStorage(key *big.Int, value *ethutil.Value)
+}
+
+type Account interface {
+	SubBalance(amount *big.Int)
+	AddBalance(amount *big.Int)
+	Balance() *big.Int
+}
+
+// generic transfer method
+func Transfer(from, to Account, amount *big.Int) error {
+	if from.Balance().Cmp(amount) < 0 {
+		return errors.New("Insufficient balance in account")
+	}
+
+	from.SubBalance(amount)
+	to.AddBalance(amount)
+
+	return nil
+}