private void Save(MemoryMappedFile mmf, Block block)
{
if (block.Size < 256)
{
throw new ArgumentOutOfRangeException(nameof(block));
}
//// 最小数
//var min = MinSize;
//if (block.Size < min) block.Size = min;
// 索引区结构：头部 + 哈希桶 + 链表数据
// 前面256字节为头部
var buf = new Byte[256];
var ms = new MemoryStream(buf);
// 头部
var bk1 = new Block(8 * 5, 256 - 8 * 5);
var bk2 = new Block(bk1.Position + bk1.Size, 31 * 16);
var bk3 = new Block(bk2.Position + bk2.Size, 1024 * 1024);
var writer = new BinaryWriter(ms);
writer.Write((Int32)bk2.Position);
writer.Write((Int32)bk2.Size);
writer.Write((Int32)bk3.Position);
writer.Write((Int32)bk3.Size);
// 校验
var crc = buf.ReadBytes(0, (Int32)ms.Position).Crc();
writer.Write(crc);
// 写回去
using (var ac = mmf.CreateAccessor(block))
{
ac.WriteArray(block.Position, buf, 0, buf.Length);
}
// 头部
_head = mmf.CreateAccessor(bk1 + block.Position);
// 哈希桶
_buckets = mmf.CreateAccessor(bk2 + block.Position);
// 链表数据
_data = mmf.CreateAccessor(bk3 + block.Position);
}
//private MemoryMappedViewAccessor GetAccessor()
//{
// var accessor = _mmf.CreateAccessor(_block);
// return accessor;
//}
private Boolean Load(MemoryMappedFile mmf, Block block)
{
if (block.Size < 256)
{
return(false);
}
// 索引区结构：头部 + 哈希桶 + 链表数据
var ac = mmf.CreateAccessor(block);
// 前面256字节为头部
var buf = ac.ReadArray(0, 256);
var ms = new MemoryStream(buf);
var reader = new BinaryReader(ms);
// 头部
var bk2 = new Block(reader.ReadInt32(), reader.ReadInt32());
var bk3 = new Block(reader.ReadInt32(), reader.ReadInt32());
var len = (Int32)ms.Position;
var crc = reader.ReadUInt32();
// 校验数据
if (crc != buf.ReadBytes(0, len).Crc())
{
return(false);
}
// 头部
_head = mmf.CreateViewAccessor(block.Position + ms.Position, ms.Length - ms.Position);
// 哈希桶
_buckets = mmf.CreateAccessor(bk2 + block.Position);
// 链表数据
_data = mmf.CreateAccessor(bk3 + block.Position);
return(true);
}
