/// <summary>实例化一个内存集合</summary>
/// <param name="mf">内存文件</param>
/// <param name="offset">内存偏移</param>
/// <param name="size">内存大小。为0时自动增长</param>
public MemoryCollection(MemoryFile mf, Int64 offset, Int64 size)
{
if (offset == 0 && size == 0)
{
View = mf.CreateView();
size = View.Capacity;
}
else
{
View = mf.CreateView(offset, size);
}
// 根据视图大小计算出可存储对象个数
var n = size - _HeadSize;
Capacity = (Int32)(n / _ItemSize);
}
/// <summary>实例化数据堆</summary>
/// <param name="mf"></param>
/// <param name="offset"></param>
/// <param name="size"></param>
/// <param name="init">自动初始化</param>
public Heap(MemoryFile mf, Int64 offset = 0, Int64 size = 0, Boolean init = true)
{
if (mf == null)
{
throw new ArgumentNullException(nameof(mf));
}
// 内存映射未初始化时 mf.Capacity=0
//if (offset < 0 || offset >= mf.Capacity && mf.Capacity > 0) throw new ArgumentOutOfRangeException(nameof(offset));
//if (size < 0) size = mf.Capacity - offset;
Position = offset;
Size = size;
View = mf.CreateView(offset, size);
if (init)
{
Init();
}
}
/// <summary>实例化数据库</summary>
/// <param name="file">文件</param>
/// <param name="readOnly">只读</param>
/// <param name="init">自动初始化</param>
public ListDb(String file, Boolean readOnly, Boolean init = true)
{
File = new MemoryFile(file, readOnly);
ReadOnly = readOnly;
if (readOnly)
{
View = File.CreateView(HEADER_SIZE, MAX_SIZE);
}
else
{
Heap = new Heap(File, HEADER_SIZE, MAX_SIZE, false);
View = Heap.View;
}
// 加大步进增长率，减少映射次数，提升性能
//View.StepRate = 100;
// 加载
if (init)
{
Init();
}
}