105 lines
1.9 KiB
Go
105 lines
1.9 KiB
Go
package ethutil
|
|
|
|
import "math/big"
|
|
|
|
var MaxInt256 *big.Int = BigD(Hex2Bytes("ffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff"))
|
|
|
|
// Big pow
|
|
//
|
|
// Returns the power of two big integers
|
|
func BigPow(a, b int) *big.Int {
|
|
c := new(big.Int)
|
|
c.Exp(big.NewInt(int64(a)), big.NewInt(int64(b)), big.NewInt(0))
|
|
|
|
return c
|
|
}
|
|
|
|
// Big
|
|
//
|
|
// Shortcut for new(big.Int).SetString(..., 0)
|
|
func Big(num string) *big.Int {
|
|
n := new(big.Int)
|
|
n.SetString(num, 0)
|
|
|
|
return n
|
|
}
|
|
|
|
// BigD
|
|
//
|
|
// Shortcut for new(big.Int).SetBytes(...)
|
|
func BigD(data []byte) *big.Int {
|
|
n := new(big.Int)
|
|
n.SetBytes(data)
|
|
|
|
return n
|
|
}
|
|
|
|
// To256
|
|
//
|
|
// "cast" the big int to a 256 big int (i.e., limit to)
|
|
var tt256 = new(big.Int).Lsh(big.NewInt(1), 256)
|
|
var tt256m1 = new(big.Int).Sub(new(big.Int).Lsh(big.NewInt(1), 256), big.NewInt(1))
|
|
var tt255 = new(big.Int).Lsh(big.NewInt(1), 255)
|
|
|
|
func U256(x *big.Int) *big.Int {
|
|
//if x.Cmp(Big0) < 0 {
|
|
// return new(big.Int).Add(tt256, x)
|
|
// }
|
|
|
|
x.And(x, tt256m1)
|
|
|
|
return x
|
|
}
|
|
|
|
func S256(x *big.Int) *big.Int {
|
|
if x.Cmp(tt255) < 0 {
|
|
return x
|
|
} else {
|
|
// We don't want to modify x, ever
|
|
return new(big.Int).Sub(x, tt256)
|
|
}
|
|
}
|
|
|
|
// Big to bytes
|
|
//
|
|
// Returns the bytes of a big integer with the size specified by **base**
|
|
// Attempts to pad the byte array with zeros.
|
|
func BigToBytes(num *big.Int, base int) []byte {
|
|
ret := make([]byte, base/8)
|
|
|
|
if len(num.Bytes()) > base/8 {
|
|
return num.Bytes()
|
|
}
|
|
|
|
return append(ret[:len(ret)-len(num.Bytes())], num.Bytes()...)
|
|
}
|
|
|
|
// Big copy
|
|
//
|
|
// Creates a copy of the given big integer
|
|
func BigCopy(src *big.Int) *big.Int {
|
|
return new(big.Int).Set(src)
|
|
}
|
|
|
|
// Big max
|
|
//
|
|
// Returns the maximum size big integer
|
|
func BigMax(x, y *big.Int) *big.Int {
|
|
if x.Cmp(y) <= 0 {
|
|
return y
|
|
}
|
|
|
|
return x
|
|
}
|
|
|
|
// Big min
|
|
//
|
|
// Returns the minimum size big integer
|
|
func BigMin(x, y *big.Int) *big.Int {
|
|
if x.Cmp(y) >= 0 {
|
|
return y
|
|
}
|
|
|
|
return x
|
|
}
|