content: /*
   * Licensed to the Apache Software Foundation (ASF) under one
   * or more contributor license agreements.  See the NOTICE file
   * distributed with this work for additional information
   * regarding copyright ownership.  The ASF licenses this file
   * 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
   *
   * Unless required by applicable law or agreed to in writing, software
   * distributed under the License is distributed on an "AS IS" BASIS,
   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
   * See the License for the specific language governing permissions and
   * limitations under the License.
   */
  
  package org.apache.cassandra.index.sai.disk.v1.vector;
  
  
  import java.util.function.Function;
  
  public class DiskBinarySearch
  {
      /**
       * Search for the target int between positions low and high, using the provided function
       * to retrieve the int value at the given ordinal.
       *
       * Returns the position at which target is found.  Raises an exception if it is not found.
       *
       * This will not call f() after the target is found, so if f is performing disk seeks,
       * it will leave the underlying reader at the position right after reading the target.
       *
       * @return index if target is found; otherwise return -1 if targer is not found
       */
      public static long searchInt(long low, long high, int target, Function<Long, Integer> f)
      {
          assert high < Long.MAX_VALUE >> 2 : "high is too large to avoid potential overflow: " + high;
          assert low < high : "low must be less than high: " + low + " >= " + high;
  
          while (low < high)
          {
              long i = low + (high - low) / 2;
              int value = f.apply(i);
              if (target == value)
                  return i;
              else if (target > value)
                  low = i + 1;
              else
                  high = i;
          }
          return -1;
      }
  }
  