content: /*
   * Licensed 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 io.airlift.compress.v3.zstd;
  
  import java.util.Arrays;
  
  import static io.airlift.compress.v3.zstd.UnsafeUtil.UNSAFE;
  import static sun.misc.Unsafe.ARRAY_BYTE_BASE_OFFSET;
  
  final class Histogram
  {
      private Histogram()
      {
      }
  
      // TODO: count parallel heuristic for large inputs
      private static void count(Object inputBase, long inputAddress, int inputSize, int[] counts)
      {
          long input = inputAddress;
  
          Arrays.fill(counts, 0);
  
          for (int i = 0; i < inputSize; i++) {
              int symbol = UNSAFE.getByte(inputBase, input) & 0xFF;
              input++;
              counts[symbol]++;
          }
      }
  
      public static int findLargestCount(int[] counts, int maxSymbol)
      {
          int max = 0;
          for (int i = 0; i <= maxSymbol; i++) {
              if (counts[i] > max) {
                  max = counts[i];
              }
          }
  
          return max;
      }
  
      public static int findMaxSymbol(int[] counts, int maxSymbol)
      {
          while (counts[maxSymbol] == 0) {
              maxSymbol--;
          }
          return maxSymbol;
      }
  
      public static void count(byte[] input, int length, int[] counts)
      {
          count(input, ARRAY_BYTE_BASE_OFFSET, length, counts);
      }
  }
  