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Int+extension.swift (1289B)

      1 /*
      2  * Copyright 2023 Google Inc. All rights reserved.
      3  *
      4  * Licensed under the Apache License, Version 2.0 (the "License");
      5  * you may not use this file except in compliance with the License.
      6  * You may obtain a copy of the License at
      7  *
      8  *     http://www.apache.org/licenses/LICENSE-2.0
      9  *
     10  * Unless required by applicable law or agreed to in writing, software
     11  * distributed under the License is distributed on an "AS IS" BASIS,
     12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
     13  * See the License for the specific language governing permissions and
     14  * limitations under the License.
     15  */
     16 
     17 #if !os(WASI)
     18 import Foundation
     19 #else
     20 import SwiftOverlayShims
     21 #endif
     22 
     23 extension Int {
     24 
     25   /// Moves the current int into the nearest power of two
     26   ///
     27   /// This is used since the UnsafeMutableRawPointer will face issues when writing/reading
     28   /// if the buffer alignment exceeds that actual size of the buffer
     29   var convertToPowerofTwo: Int {
     30     guard self > 0 else { return 1 }
     31     var n = UOffset(self)
     32 
     33     #if arch(arm) || arch(i386)
     34     let max = UInt32(Int.max)
     35     #else
     36     let max = UInt32.max
     37     #endif
     38 
     39     n -= 1
     40     n |= n >> 1
     41     n |= n >> 2
     42     n |= n >> 4
     43     n |= n >> 8
     44     n |= n >> 16
     45     if n != max {
     46       n += 1
     47     }
     48 
     49     return Int(n)
     50   }
     51 }