1  using System;
  2  using System.Collections.Generic;
  3  
  4  namespace Ryujinx.Graphics.Vulkan
  5  {
  6      class IdList<T> where T : class
  7      {
  8          private readonly List<T> _list;
  9          private int _freeMin;
 10  
 11          public IdList()
 12          {
 13              _list = new List<T>();
 14              _freeMin = 0;
 15          }
 16  
 17          public int Add(T value)
 18          {
 19              int id;
 20              int count = _list.Count;
 21              id = _list.IndexOf(null, _freeMin);
 22  
 23              if ((uint)id < (uint)count)
 24              {
 25                  _list[id] = value;
 26              }
 27              else
 28              {
 29                  id = count;
 30                  _freeMin = id + 1;
 31  
 32                  _list.Add(value);
 33              }
 34  
 35              return id + 1;
 36          }
 37  
 38          public void Remove(int id)
 39          {
 40              id--;
 41  
 42              int count = _list.Count;
 43  
 44              if ((uint)id >= (uint)count)
 45              {
 46                  return;
 47              }
 48  
 49              if (id + 1 == count)
 50              {
 51                  // Trim unused items.
 52                  int removeIndex = id;
 53  
 54                  while (removeIndex > 0 && _list[removeIndex - 1] == null)
 55                  {
 56                      removeIndex--;
 57                  }
 58  
 59                  _list.RemoveRange(removeIndex, count - removeIndex);
 60  
 61                  if (_freeMin > removeIndex)
 62                  {
 63                      _freeMin = removeIndex;
 64                  }
 65              }
 66              else
 67              {
 68                  _list[id] = null;
 69  
 70                  if (_freeMin > id)
 71                  {
 72                      _freeMin = id;
 73                  }
 74              }
 75          }
 76  
 77          public bool TryGetValue(int id, out T value)
 78          {
 79              id--;
 80  
 81              try
 82              {
 83                  if ((uint)id < (uint)_list.Count)
 84                  {
 85                      value = _list[id];
 86                      return value != null;
 87                  }
 88  
 89                  value = null;
 90                  return false;
 91              }
 92              catch (ArgumentOutOfRangeException)
 93              {
 94                  value = null;
 95                  return false;
 96              }
 97              catch (IndexOutOfRangeException)
 98              {
 99                  value = null;
100                  return false;
101              }
102          }
103  
104          public void Clear()
105          {
106              _list.Clear();
107              _freeMin = 0;
108          }
109  
110          public IEnumerator<T> GetEnumerator()
111          {
112              for (int i = 0; i < _list.Count; i++)
113              {
114                  if (_list[i] != null)
115                  {
116                      yield return _list[i];
117                  }
118              }
119          }
120      }
121  }