github.com/maypok86/otter@v1.2.1/internal/xmath/power.go (about)

     1  // Copyright (c) 2023 Alexey Mayshev. All rights reserved.
     2  //
     3  // Licensed under the Apache License, Version 2.0 (the "License");
     4  // you may not use this file except in compliance with the License.
     5  // You may obtain a copy of the License at
     6  //
     7  //     http://www.apache.org/licenses/LICENSE-2.0
     8  //
     9  // Unless required by applicable law or agreed to in writing, software
    10  // distributed under the License is distributed on an "AS IS" BASIS,
    11  // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    12  // See the License for the specific language governing permissions and
    13  // limitations under the License.
    14  
    15  package xmath
    16  
    17  // RoundUpPowerOf2 is based on https://graphics.stanford.edu/~seander/bithacks.html#RoundUpPowerOf2.
    18  func RoundUpPowerOf2(v uint32) uint32 {
    19  	if v == 0 {
    20  		return 1
    21  	}
    22  	v--
    23  	v |= v >> 1
    24  	v |= v >> 2
    25  	v |= v >> 4
    26  	v |= v >> 8
    27  	v |= v >> 16
    28  	v++
    29  	return v
    30  }