package vm import ( "math/big" "github.com/ethereum/go-ethereum/crypto" "github.com/ethereum/go-ethereum/common" ) 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 GasEcrecover }, ecrecoverFunc}, // SHA256 string(common.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(common.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(common.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 common.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 := common.BigD(in[32:64]).Bytes()[0] - 27 sig := append(in[64:], v) return common.LeftPadBytes(crypto.Sha3(crypto.Ecrecover(append(hash, sig...))[1:])[12:], 32) } func memCpy(in []byte) []byte { return in }