public VFSCore(AbstractDevice device)
{
this.device = device;
this.deviceSize = device.Size();
// 初始化超级块
this.superBlock = SuperBlock.Load(this);
if (IsFormated())
{
loadBitmaps();
Console.WriteLine("载入镜像成功。");
Console.WriteLine("SuperBlock: {0}", superBlock.ToString());
}
}
/// <summary>
/// 格式化存储介质
/// </summary>
/// <param name="inodeCapacity">inode 数量</param>
/// <param name="blockSizeKByte">block 大小（KB），必须为 1，2，4，8 中的一个</param>
public void Format(UInt32 inodeCapacity, UInt16 blockSizeKByte = 4)
{
if (inodeCapacity < 32)
{
throw new Exception("inode 至少为 32 个");
}
if (!new int[] { 1, 2, 4, 8 }.Contains(blockSizeKByte))
{
throw new Exception("block 大小只能为 1KB, 2KB, 4KB 或 8KB");
}
uint offset = 0;
offset += (uint)Utils.GetStructSize<_SuperBlock>();
offset += (inodeCapacity / 32 + 1) * 4;
offset += (uint)Utils.GetStructSize<_INode>() * inodeCapacity;
if (offset > deviceSize)
{
throw new Exception("inode 数量过大，结构超出存储介质最大空间");
}
// 可留给数据块位图和数据块区的大小
uint sizeRemain = deviceSize - offset;
// 全部留给数据块，可以有多少个数据块
uint blockCapacity = sizeRemain / blockSizeKByte >> 10;
if (blockCapacity < 128)
{
throw new Exception("磁盘空间太小，至少要可以容纳 128 个块");
}
// 删除 (blockCapacity / 32 + 1) * 4 大小的数据块，留作数据块位图使用
blockCapacity -= ((blockCapacity / 32 + 1) * 4 / blockSizeKByte) + 1;
// 初始化 superBlock
superBlock = SuperBlock.Create(this, inodeCapacity, (UInt16)(blockSizeKByte << 10), blockCapacity);
// 单个 inode BitVector 可容纳 32 位
inodeBitmaps = new UInt32[inodeCapacity / 32 + 1];
device.WriteArray(superBlock.pInodeBitVectors, inodeBitmaps, 0, inodeBitmaps.Length);
// 单个 block BitVector 可容纳 32 位
blockBitmaps = new UInt32[blockCapacity / 32 + 1];
device.WriteArray(superBlock.pBlockBitVectors, blockBitmaps, 0, blockBitmaps.Length);
// 写入根目录
INodeDirectory.Create(this);
Console.WriteLine("格式化成功。");
Console.WriteLine("SuperBlock: {0}", superBlock.ToString());
}
/// <summary>
/// 创建一个全新的 SuperBlock
/// </summary>
/// <param name="vfs"></param>
/// <param name="inodeCapacity"></param>
/// <param name="blockSize"></param>
/// <param name="blockCapacity"></param>
/// <returns></returns>
public static SuperBlock Create(VFSCore vfs, UInt32 inodeCapacity, UInt16 blockSize, UInt32 blockCapacity)
{
var _superBlock = new _SuperBlock(inodeCapacity, blockSize, blockCapacity);
var superBlock = new SuperBlock(vfs, _superBlock);
superBlock.Save();
return superBlock;
}