1 files changed, 102 insertions, 0 deletions
diff --git a/core/vm/contracts.go b/core/vm/contracts.go
new file mode 100644
index 000000000..90e356b1d
--- /dev/null
+++ b/core/vm/contracts.go
@@ -0,0 +1,102 @@
+package vm
+
+import (
+	"math/big"
+
+	"github.com/ethereum/go-ethereum/common"
+	"github.com/ethereum/go-ethereum/crypto"
+	"github.com/ethereum/go-ethereum/logger"
+	"github.com/ethereum/go-ethereum/logger/glog"
+	"github.com/ethereum/go-ethereum/params"
+)
+
+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(common.LeftPadBytes([]byte{1}, 20)): &PrecompiledAccount{func(l int) *big.Int {
+			return params.EcrecoverGas
+		}, ecrecoverFunc},
+
+		// SHA256
+		string(common.LeftPadBytes([]byte{2}, 20)): &PrecompiledAccount{func(l int) *big.Int {
+			n := big.NewInt(int64(l+31) / 32)
+			n.Mul(n, params.Sha256WordGas)
+			return n.Add(n, params.Sha256Gas)
+		}, sha256Func},
+
+		// RIPEMD160
+		string(common.LeftPadBytes([]byte{3}, 20)): &PrecompiledAccount{func(l int) *big.Int {
+			n := big.NewInt(int64(l+31) / 32)
+			n.Mul(n, params.Ripemd160WordGas)
+			return n.Add(n, params.Ripemd160Gas)
+		}, ripemd160Func},
+
+		string(common.LeftPadBytes([]byte{4}, 20)): &PrecompiledAccount{func(l int) *big.Int {
+			n := big.NewInt(int64(l+31) / 32)
+			n.Mul(n, params.IdentityWordGas)
+
+			return n.Add(n, params.IdentityGas)
+		}, memCpy},
+	}
+}
+
+func sha256Func(in []byte) []byte {
+	return crypto.Sha256(in)
+}
+
+func ripemd160Func(in []byte) []byte {
+	return common.LeftPadBytes(crypto.Ripemd160(in), 32)
+}
+
+const ecRecoverInputLength = 128
+
+func ecrecoverFunc(in []byte) []byte {
+	in = common.RightPadBytes(in, 128)
+	// "in" is (hash, v, r, s), each 32 bytes
+	// but for ecrecover we want (r, s, v)
+
+	r := common.BytesToBig(in[64:96])
+	s := common.BytesToBig(in[96:128])
+	// Treat V as a 256bit integer
+	vbig := common.Bytes2Big(in[32:64])
+	v := byte(vbig.Uint64())
+
+	if !crypto.ValidateSignatureValues(v, r, s) {
+		glog.V(logger.Error).Infof("EC RECOVER FAIL: v, r or s value invalid")
+		return nil
+	}
+
+	// v needs to be at the end and normalized for libsecp256k1
+	vbignormal := new(big.Int).Sub(vbig, big.NewInt(27))
+	vnormal := byte(vbignormal.Uint64())
+	rsv := append(in[64:128], vnormal)
+	pubKey, err := crypto.Ecrecover(in[:32], rsv)
+	// make sure the public key is a valid one
+	if err != nil {
+		glog.V(logger.Error).Infof("EC RECOVER FAIL: ", err)
+		return nil
+	}
+
+	// the first byte of pubkey is bitcoin heritage
+	return common.LeftPadBytes(crypto.Sha3(pubKey[1:])[12:], 32)
+}
+
+func memCpy(in []byte) []byte {
+	return in
+}