/// <summary>
/// 查找指定偏移所在的块，若块不存在则返回无效块
/// </summary>
/// <param name="position"></param>
/// <returns></returns>
public Block GetBlockAtPosition(UInt32 position, Boolean allocate = false)
{
UInt32 blockSize = vfs.GetSuperBlock().data.blockSize;
UInt32 IndexPerBlock = blockSize / sizeof(UInt32);
if (position < BoundLv0)
{
// 直接索引
UInt32 lv0_index = position / blockSize;
return(new Block(vfs, data.dataBlockId[lv0_index]));
}
else if (position < BoundLv1)
{
// 一级间接索引
position -= BoundLv0;
UInt32 lv0_index = 12;
UInt32 lv1_index = position / blockSize;
Block lv0_block = new Block(vfs, data.dataBlockId[lv0_index]);
if (lv0_block.index == UInt32.MaxValue)
{
return(lv0_block);
}
return(new Block(vfs, lv0_block.Read <UInt32>(lv1_index * sizeof(UInt32))));
}
else
{
// 二级间接索引
position -= BoundLv1;
UInt32 lv0_index = 13;
UInt32 lv1_index = (position / blockSize) / IndexPerBlock;
UInt32 lv2_index = (position / blockSize) % IndexPerBlock;
Block lv0_block = new Block(vfs, data.dataBlockId[lv0_index]);
if (lv0_block.index == UInt32.MaxValue)
{
return(lv0_block);
}
Block lv1_block = new Block(vfs, lv0_block.Read <UInt32>(lv1_index * sizeof(UInt32)));
if (lv1_block.index == UInt32.MaxValue)
{
return(lv1_block);
}
return(new Block(vfs, lv1_block.Read <UInt32>(lv2_index * sizeof(UInt32))));
}
}
/// <summary>
/// 从存储介质中获取 inode
/// </summary>
/// <param name="vfs"></param>
/// <param name="index"></param>
/// <returns></returns>
public static INode Load(VFSCore vfs, UInt32 index)
{
if (index >= vfs.GetSuperBlock().data.inodeCapacity)
{
throw new Exception("无效 inode 编号");
}
INode inode = null;
if (inodeInstances.ContainsKey(index))
{
inode = inodeInstances[index];
return(inode);
}
else
{
_INode data = vfs.GetDevice().Read <_INode>(GetPosition(vfs, index));
inode = new INode(vfs, data, index);
inodeInstances[index] = inode;
}
inode.data.accessTime = (UInt64)DateTime.Now.Ticks;
inode.Save();
return(inode);
}
public INode(VFSCore vfs, _INode data, UInt32 index = UInt32.MaxValue)
{
this.vfs = vfs;
this.data = data;
this.index = index;
UInt32 blockSize = vfs.GetSuperBlock().data.blockSize;
UInt32 IndexPerBlock = blockSize / sizeof(UInt32);
BoundLv0 = 12 * blockSize;
BoundLv1 = BoundLv0 + IndexPerBlock * blockSize;
}
/// <summary>
/// 创建一个新的 inode
/// </summary>
/// <param name="vfs"></param>
/// <param name="index"></param>
/// <returns></returns>
public static INode Create(VFSCore vfs, UInt32 index, UInt32 flags, UInt32 owner)
{
if (index >= vfs.GetSuperBlock().data.inodeCapacity)
{
throw new Exception("无效 inode 编号");
}
_INode data = new _INode(flags, owner);
INode inode = new INode(vfs, data, index);
inode.Save();
inodeInstances[index] = inode;
return(inode);
}
public static UInt32 GetPosition(VFSCore vfs, UInt32 index)
{
return(vfs.GetSuperBlock().pInodeData + index * (uint)Utils.GetStructSize <_INode>());
}
public _SuperBlock GetSuperBlock()
{
return(vfs.GetSuperBlock().data);
}
/// <summary>
/// 从存储介质中获取 inode
/// </summary>
/// <param name="vfs"></param>
/// <param name="index"></param>
/// <returns></returns>
public static INode Load(VFSCore vfs, UInt32 index)
{
if (index >= vfs.GetSuperBlock().data.inodeCapacity)
{
throw new Exception("无效 inode 编号");
}
INode inode = null;
if (inodeInstances.ContainsKey(index))
{
inode = inodeInstances[index];
return inode;
}
else
{
_INode data = vfs.GetDevice().Read<_INode>(GetPosition(vfs, index));
inode = new INode(vfs, data, index);
inodeInstances[index] = inode;
}
inode.data.accessTime = (UInt64)DateTime.Now.Ticks;
inode.Save();
return inode;
}
public static UInt32 GetPosition(VFSCore vfs, UInt32 index)
{
return vfs.GetSuperBlock().pInodeData + index * (uint)Utils.GetStructSize<_INode>();
}
/// <summary>
/// 创建一个新的 inode
/// </summary>
/// <param name="vfs"></param>
/// <param name="index"></param>
/// <returns></returns>
public static INode Create(VFSCore vfs, UInt32 index, UInt32 flags, UInt32 owner)
{
if (index >= vfs.GetSuperBlock().data.inodeCapacity)
{
throw new Exception("无效 inode 编号");
}
_INode data = new _INode(flags, owner);
INode inode = new INode(vfs, data, index);
inode.Save();
inodeInstances[index] = inode;
return inode;
}
public INode(VFSCore vfs, _INode data, UInt32 index = UInt32.MaxValue)
{
this.vfs = vfs;
this.data = data;
this.index = index;
UInt32 blockSize = vfs.GetSuperBlock().data.blockSize;
UInt32 IndexPerBlock = blockSize / sizeof(UInt32);
BoundLv0 = 12 * blockSize;
BoundLv1 = BoundLv0 + IndexPerBlock * blockSize;
}