/*
    * Copyright 2024 The Netty Project
    *
    * The Netty Project 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:
    *
    *   https://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.netty.channel.uring;
  
  import java.util.Arrays;
  
  final class MsgHdrMemoryArray {
      static final long NO_ID = 0;
  
      private final MsgHdrMemory[] hdrs;
      private final int capacity;
      private final long[] ids;
      private boolean released;
      private int idx;
  
      MsgHdrMemoryArray(short capacity) {
          assert capacity >= 0;
          this.capacity = capacity;
          hdrs = new MsgHdrMemory[capacity];
          ids = new long[capacity];
          for (int i = 0; i < hdrs.length; i++) {
              hdrs[i] = new MsgHdrMemory((short) i);
              ids[i] = NO_ID;
          }
      }
  
      MsgHdrMemory nextHdr() {
          if (idx == hdrs.length) {
              return null;
          }
          return hdrs[idx++];
      }
  
      void restoreNextHdr(MsgHdrMemory hdr) {
          assert hdr.idx() == idx - 1;
          idx--;
      }
  
      MsgHdrMemory hdr(int idx) {
          return hdrs[idx];
      }
  
      long id(int idx) {
          return ids[idx];
      }
  
      void setId(int idx, long id) {
          ids[idx] = id;
      }
  
      void clear() {
          Arrays.fill(ids, 0, idx, NO_ID);
          idx = 0;
      }
  
      int length() {
          return idx;
      }
  
      void release() {
          assert !released;
          released = true;
          for (MsgHdrMemory hdr: hdrs) {
              hdr.release();
          }
      }
  
      int capacity() {
          return capacity;
      }
  }