/*
    * Copyright 2020-2022 The OSHI Project Contributors
    * SPDX-License-Identifier: MIT
    */
   package oshi.driver.unix.aix.perfstat;
   
   import com.sun.jna.platform.unix.aix.Perfstat;
   import com.sun.jna.platform.unix.aix.Perfstat.perfstat_id_t;
   import com.sun.jna.platform.unix.aix.Perfstat.perfstat_protocol_t;
  
  import oshi.annotation.concurrent.ThreadSafe;
  
  /**
   * Utility to query performance stats for network interfaces
   */
  @ThreadSafe
  public final class PerfstatProtocol {
  
      private static final Perfstat PERF = Perfstat.INSTANCE;
  
      private PerfstatProtocol() {
      }
  
      /**
       * Queries perfstat_protocol for per-protocol usage statistics
       *
       * @return an array of usage statistics
       */
      public static perfstat_protocol_t[] queryProtocols() {
          perfstat_protocol_t protocol = new perfstat_protocol_t();
          // With null, null, ..., 0, returns total # of elements
          int total = PERF.perfstat_protocol(null, null, protocol.size(), 0);
          if (total > 0) {
              perfstat_protocol_t[] statp = (perfstat_protocol_t[]) protocol.toArray(total);
              perfstat_id_t firstprotocol = new perfstat_id_t(); // name is ""
              int ret = PERF.perfstat_protocol(firstprotocol, statp, protocol.size(), total);
              if (ret > 0) {
                  return statp;
              }
          }
          return new perfstat_protocol_t[0];
      }
  }