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util.go
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util.go
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/*
* Copyright (C) 2018 The DNA Authors
* This file is part of The DNA library.
*
* The DNA is free software: you can redistribute it and/or modify
* it under the terms of the GNU Lesser General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* The DNA is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public License
* along with The DNA. If not, see <http://www.gnu.org/licenses/>.
*/
package merkle
// return the number of 1 bit
func countBit(num uint32) uint {
var count uint
for num != 0 {
num &= (num - 1)
count += 1
}
return count
}
func isPower2(num uint32) bool {
return countBit(num) == 1
}
// return the position of the heightest 1 bit
// 1-based index
func highBit(num uint32) uint {
var hiBit uint
for num != 0 {
num >>= 1
hiBit += 1
}
return hiBit
}
// return the position of the lowest 1 bit
// 1-based index
func lowBit(num uint32) uint {
return highBit(num & -num)
}