fe/src/main/java/org/apache/impala/util/BitUtil.java

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// to you under the Apache License, Version 2.0 (the
// "License"); you may not use this file except in compliance
// with the License.  You may obtain a copy of the License at
//
//   http://www.apache.org/licenses/LICENSE-2.0
//
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package org.apache.impala.util;

public class BitUtil {

  // Returns the log2 of 'val'. 'val' must be > 0.
  public static int log2Ceiling(long val) {
    // Formula is based on the Long.numberOfLeadingZeros() javadoc comment.
    return 64 - Long.numberOfLeadingZeros(val - 1);
  }

  // Round up 'val' to the nearest power of two. 'val' must be > 0.
  public static long roundUpToPowerOf2(long val) {
    return 1L << log2Ceiling(val);
  }

  // Round up 'val' to the nearest multiple of a power-of-two 'factor'.
  // 'val' must be > 0.
  public static long roundUpToPowerOf2Factor(long val, long factor) {
    return (val + (factor - 1)) & ~(factor - 1);
  }
}