content: /*
   * Copyright (C) 2016-2023 ActionTech.
   * License: http://www.gnu.org/licenses/gpl.html GPL version 2 or higher.
   */
  
  package com.actiontech.dble.statistic.sql.analyzer;
  
  import java.util.concurrent.atomic.AtomicLongArray;
  
  public class Histogram {
  
      private final long[] ranges;
      private final AtomicLongArray rangeCounters;
  
      public Histogram(long... ranges) {
          this.ranges = ranges;
          this.rangeCounters = new AtomicLongArray(ranges.length);
      }
  
      public void reset() {
          for (int i = 0; i < rangeCounters.length(); i++) {
              rangeCounters.set(i, 0);
          }
      }
  
      public void record(long range) {
          int index = rangeCounters.length();
          for (int i = 0; i < ranges.length; i++) {
              if (range == ranges[i]) {
                  index = i;
                  break;
              }
          }
  
          rangeCounters.incrementAndGet(index);
      }
  
      public long get(int index) {
          return rangeCounters.get(index);
      }
  
      public long[] toArray() {
          long[] array = new long[rangeCounters.length()];
          for (int i = 0; i < rangeCounters.length(); i++) {
              array[i] = rangeCounters.get(i);
          }
          return array;
      }
  
      public long[] toArrayAndReset() {
          long[] array = new long[rangeCounters.length()];
          for (int i = 0; i < rangeCounters.length(); i++) {
              array[i] = rangeCounters.getAndSet(i, 0);
          }
  
          return array;
      }
  
      public long[] getRanges() {
          return ranges;
      }
  
      public long getValue(int index) {
          return rangeCounters.get(index);
      }
  
      public long getSum() {
          long sum = 0;
          for (int i = 0; i < rangeCounters.length(); ++i) {
              sum += rangeCounters.get(i);
          }
          return sum;
      }
  
      public String toString() {
          StringBuilder buf = new StringBuilder();
          buf.append('[');
          for (int i = 0; i < rangeCounters.length(); i++) {
              if (i != 0) {
                  buf.append(", ");
              }
              buf.append(rangeCounters.get(i));
          }
          buf.append(']');
          return buf.toString();
      }
  }
  