poanetwork
/
quorum
mirror of https://github.com/poanetwork/quorum.git
1
0
Fork 0
Code Issues Projects Releases Wiki Activity

common/math: "optimised" SafeMul and added comment on Exp (#3675)

This commit is contained in:
Jeffrey Wilcke 2017-02-17 18:39:43 +01:00 committed by GitHub
parent 6f74fb962e
commit bf21549faa
2 changed files with 5 additions and 2 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

3
common/math/exp.go
View File

@ -27,6 +27,9 @@ const wordSize = 32 << (uint64(^big.Word(0)) >> 63)
// Exp implement exponentiation by squaring algorithm.
//
// Exp return a new variable; base and exponent must
// not be changed under any circumstance.
//
// Courtesy @karalabe and @chfast
func Exp(base, exponent *big.Int) *big.Int {
result := big.NewInt(1)

4
common/math/integer.go
View File

@ -18,8 +18,8 @@ func SafeAdd(x, y uint64) (uint64, bool) {
// SafeMul returns multiplication result and whether overflow occurred.
func SafeMul(x, y uint64) (uint64, bool) {
if x == 0 {
if x == 0 || y == 0 {
return 0, false
}
return x * y, x != 0 && y != 0 && y > gmath.MaxUint64/x
return x * y, y > gmath.MaxUint64/x
}