1 files changed, 77 insertions, 0 deletions
diff --git a/vm/address.go b/vm/address.go
new file mode 100644
index 000000000..b1345da8f
--- /dev/null
+++ b/vm/address.go
@@ -0,0 +1,77 @@
+package vm
+
+import (
+	"math/big"
+
+	"github.com/ethereum/go-ethereum/crypto"
+	"github.com/ethereum/go-ethereum/ethutil"
+)
+
+type Address interface {
+	Call(in []byte) []byte
+}
+
+type PrecompiledAccount struct {
+	Gas func(l int) *big.Int
+	fn  func(in []byte) []byte
+}
+
+func (self PrecompiledAccount) Call(in []byte) []byte {
+	return self.fn(in)
+}
+
+var Precompiled = PrecompiledContracts()
+
+// XXX Could set directly. Testing requires resetting and setting of pre compiled contracts.
+func PrecompiledContracts() map[string]*PrecompiledAccount {
+	return map[string]*PrecompiledAccount{
+		// ECRECOVER
+		string(ethutil.LeftPadBytes([]byte{1}, 20)): &PrecompiledAccount{func(l int) *big.Int {
+			return GasEcrecover
+		}, ecrecoverFunc},
+
+		// SHA256
+		string(ethutil.LeftPadBytes([]byte{2}, 20)): &PrecompiledAccount{func(l int) *big.Int {
+			n := big.NewInt(int64(l+31) / 32)
+			n.Mul(n, GasSha256Word)
+			return n.Add(n, GasSha256Base)
+		}, sha256Func},
+
+		// RIPEMD160
+		string(ethutil.LeftPadBytes([]byte{3}, 20)): &PrecompiledAccount{func(l int) *big.Int {
+			n := big.NewInt(int64(l+31) / 32)
+			n.Mul(n, GasRipemdWord)
+			return n.Add(n, GasRipemdBase)
+		}, ripemd160Func},
+
+		string(ethutil.LeftPadBytes([]byte{4}, 20)): &PrecompiledAccount{func(l int) *big.Int {
+			n := big.NewInt(int64(l+31) / 32)
+			n.Mul(n, GasIdentityWord)
+
+			return n.Add(n, GasIdentityBase)
+		}, memCpy},
+	}
+}
+
+func sha256Func(in []byte) []byte {
+	return crypto.Sha256(in)
+}
+
+func ripemd160Func(in []byte) []byte {
+	return ethutil.LeftPadBytes(crypto.Ripemd160(in), 32)
+}
+
+func ecrecoverFunc(in []byte) []byte {
+	// In case of an invalid sig. Defaults to return nil
+	defer func() { recover() }()
+
+	hash := in[:32]
+	v := ethutil.BigD(in[32:64]).Bytes()[0] - 27
+	sig := append(in[64:], v)
+
+	return ethutil.LeftPadBytes(crypto.Sha3(crypto.Ecrecover(append(hash, sig...))[1:])[12:], 32)
+}
+
+func memCpy(in []byte) []byte {
+	return in
+}