plugeth/ethutil/big.go

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package ethutil
import (
"math/big"
)
// Big pow
//
// Returns the power of two big integers
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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)
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func Big(num string) *big.Int {
n := new(big.Int)
n.SetString(num, 0)
return n
}
// BigD
//
// Shortcut for new(big.Int).SetBytes(...)
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func BigD(data []byte) *big.Int {
n := new(big.Int)
n.SetBytes(data)
return n
}
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// To256
//
// "cast" the big int to a 256 big int (i.e., limit to)
var tt256 = new(big.Int).Sub(new(big.Int).Lsh(big.NewInt(1), 256), big.NewInt(1))
func To256(x *big.Int) *big.Int {
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x.And(x, tt256)
if x.Cmp(new(big.Int)) < 0 {
x.SetInt64(0)
}
return x
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}
// Big to bytes
//
// Returns the bytes of a big integer with the size specified by **base**
// Attempts to pad the byte array with zeros.
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func BigToBytes(num *big.Int, base int) []byte {
ret := make([]byte, base/8)
if len(num.Bytes()) > base/8 {
return num.Bytes()
}
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return append(ret[:len(ret)-len(num.Bytes())], num.Bytes()...)
}
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// Big copy
//
// Creates a copy of the given big integer
func BigCopy(src *big.Int) *big.Int {
return new(big.Int).Set(src)
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}
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// Big max
//
// Returns the maximum size big integer
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func BigMax(x, y *big.Int) *big.Int {
if x.Cmp(y) <= 0 {
return y
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}
return x
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}
// 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
}