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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
}
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