/// <summary>
/// 写回空闲表
/// </summary>
/// <param name="drivename"></param>
/// <param name="volumeInfo"></param>
/// <param name="freetable"></param>
/// <returns></returns>
public static ErrorCode SetFreeBlock(string drivename, ref VolumeInfo volumeInfo, byte[] freetable)
{
var res = DiskRW.write(drivename, volumeInfo.FreeTableStart, freetable);
if (res)
{
return(ErrorCode.Success);
}
return(ErrorCode.Fail);
}
/// <summary>
/// 写入某个簇内容
/// </summary>
/// <param name="drivename">驱动器</param>
/// <param name="volumeinfo">卷信息结构体</param>
/// <param name="cluster">要写入的簇号</param>
/// <param name="content">写入内容</param>
/// <returns></returns>
public static ErrorCode WriteIn(string drivename, VolumeInfo volumeinfo, UInt32 cluster, byte[] content)
{
if (content.Length != volumeinfo.Cluster)
{
return(ErrorCode.ErrorClusterLength);
}
var res = DiskRW.write(drivename, transfer(volumeinfo.SectorStart, cluster, volumeinfo.Cluster), content);
if (res)
{
return(ErrorCode.Success);
}
return(ErrorCode.Fail);
}
public static ErrorCode SetFileInfo(string drivename, FileInfo fat)
{
byte[] buffer = DiskRW.read(drivename, fat.Location);
//name
for (int i = 0; i < 63; i++)
{
buffer[i] = 0;
}
byte[] name = Encoding.Unicode.GetBytes(fat.Name);
name.CopyTo(buffer, 0);
name = Encoding.Unicode.GetBytes(fat.Extension);
name.CopyTo(buffer, 64);
//文件号 权限号 权限标记
buffer[77] = fat.Type;
buffer[78] = fat.AccessCode;
buffer[79] = fat.AccessMode;
//作者
name = Encoding.Unicode.GetBytes(fat.Author);
name.CopyTo(buffer, 80);
//最后修改人
name = Encoding.Unicode.GetBytes(fat.LastEditor);
name.CopyTo(buffer, 112);
//创建日期
buffer[144] = (byte)(fat.CreateTime);
buffer[145] = (byte)(fat.CreateTime >> 8);
buffer[146] = (byte)(fat.CreateTime >> 16);
buffer[147] = (byte)(fat.CreateTime >> 24);
//修改日期
buffer[148] = (byte)(fat.LastEditTime);
buffer[149] = (byte)(fat.LastEditTime >> 8);
buffer[150] = (byte)(fat.LastEditTime >> 16);
buffer[151] = (byte)(fat.LastEditTime >> 24);
//尾字节长
buffer[152] = (byte)fat.Rest;
buffer[153] = (byte)(fat.Rest >> 8);
bool res = DiskRW.write(drivename, fat.Location, buffer);
if (!res)
{
return(ErrorCode.Fail);
}
return(ErrorCode.Success);
}
/// <summary>
/// 写回卷信息
/// </summary>
/// <param name="drivename">驱动器名</param>
/// <param name="volumeInfo">卷信息结构体</param>
/// <returns>错误代码</returns>
static public ErrorCode SetVolumeInfo(string drivename, VolumeInfo volumeInfo)
{
var header = new byte[512];
byte[] name = Encoding.Unicode.GetBytes("新加卷");
name.CopyTo(header, 0);
//起始簇扇区
header[32] = (byte)volumeInfo.SectorStart;
header[33] = (byte)(volumeInfo.SectorStart >> 8);
header[34] = (byte)(volumeInfo.SectorStart >> 16);
header[35] = (byte)(volumeInfo.SectorStart >> 24);
//分区长度
header[36] = (byte)(volumeInfo.SectorCount);
header[37] = (byte)(volumeInfo.SectorCount >> 8);
header[38] = (byte)(volumeInfo.SectorCount >> 16);
header[39] = (byte)(volumeInfo.SectorCount >> 24);
//分配单元大小 512B 的倍数
header[40] = (byte)(volumeInfo.Cluster >> 9);
//卷标 预留为空 ascii编码
header[41] = volumeInfo.VolumeLabel;
//空闲闲表头
header[42] = (byte)(volumeInfo.FreeTableStart);
header[43] = (byte)(volumeInfo.FreeTableStart >> 8);
header[44] = (byte)(volumeInfo.FreeTableStart >> 16);
header[45] = (byte)(volumeInfo.FreeTableStart >> 24);
//加密方式 0 不加密
header[48] = volumeInfo.EncryptionType;
bool res = DiskRW.write(drivename, volumeInfo.SectorStart, header);
if (!res)
{
return(ErrorCode.Fail);
}
return(ErrorCode.Success);
}
/// <summary>
/// 获取空闲块 位示图
/// </summary>
/// <param name="drivename"></param>
/// <param name="volumeInfo">卷信息的引用</param>
/// <param name="count">所需空闲块个数</param>
/// <returns>空闲簇列表</returns>
public static List <UInt32> GetFreeBlock(string drivename, ref VolumeInfo volumeInfo, UInt32 count)
{
UInt32 clustercount = (UInt32)((volumeInfo.SectorCount - 1) / (volumeInfo.Cluster >> 9)); //簇总数
UInt32 UseBytes = (clustercount >> 3) + 1; //用多少个字节存储
UInt32 UseCluster = UseBytes / volumeInfo.Cluster + 1; //表大小(簇)
//读取空闲表内容
byte[] content = DiskRW.ReadA(drivename, volumeInfo.FreeTableStart, UseCluster * (UInt32)(volumeInfo.Cluster >> 9));
//返回的空闲块号
List <UInt32> ls = new List <uint>();
//i为计数,j为簇索引值
UInt32 i = 0;
for (UInt32 j = 0; j < clustercount; j++)
{
if (!Test(j, content))
{
ls.Add(j);
i++;
}
if (i == count)
{
break;
}
}
//磁盘已满或没有空间返回null;
if (ls.Count < i)
{
return(null);
}
//写空闲表
foreach (UInt32 item in ls)
{
Set(item, true, content);
}
//写回磁盘
DiskRW.write(drivename, volumeInfo.FreeTableStart, content);
return(ls);
}
/// <summary>
/// 添加文件fat，文件为空
/// </summary>
/// <param name="current">当前目录信息</param>
/// <param name="drivename">驱动器名</param>
/// <param name="volumeinfo">当前卷信息</param>
/// <returns>新文件簇号</returns>
public static UInt32 AddDir(DirectInfo current, string drivename, VolumeInfo volumeinfo)
{
byte[] buffer = new byte[volumeinfo.Cluster];
var ls = GetFreeBlock(drivename, ref volumeinfo, 1);//获取存放fat的簇
//向现在目录加项
var currentDir = DiskRW.ReadA(drivename, current.Location, (UInt16)(volumeinfo.Cluster >> 9));
//检索当前的fat表
for (int i = 164; i < volumeinfo.Cluster; i += 4)
{
if (mergeByte(currentDir[i], currentDir[i + 1], currentDir[i + 2], currentDir[i + 3]) == 0)
{
currentDir[i] = (byte)ls[0];
currentDir[i + 1] = (byte)(ls[0] >> 8);
currentDir[i + 2] = (byte)(ls[0] >> 16);
currentDir[i + 3] = (byte)(ls[0] >> 24);
//写回磁盘
DiskRW.write(drivename, current.Location, currentDir);
return(ls[0]);
}
}
//fat满并且没有下个簇存放
if (mergeByte(currentDir[160], currentDir[161], currentDir[162], currentDir[163]) == 0)
{
//添加下一索引块
byte[] buffer2 = new byte[volumeinfo.Cluster];//写入内容缓存
var l2 = GetFreeBlock(drivename, ref volumeinfo, 1);
//写入上个的索引表
currentDir[160] = (byte)l2[0];
currentDir[161] = (byte)(l2[0] >> 8);
currentDir[162] = (byte)(l2[0] >> 16);
currentDir[163] = (byte)(l2[0] >> 24);
//下个
buffer2[4] = (byte)ls[0];
buffer2[5] = (byte)(ls[0] >> 8);
buffer2[6] = (byte)(ls[0] >> 16);
buffer2[7] = (byte)(ls[0] >> 24);
//写入磁盘
WriteIn(drivename, volumeinfo, l2[0], buffer2);
DiskRW.write(drivename, current.Location, currentDir);
return(ls[0]);
}
//寻找下一个索引表
currentDir = ReadOut(drivename, volumeinfo, mergeByte(currentDir[160], currentDir[161], currentDir[162], currentDir[163]));
while (true)
{
for (int i = 4; i < volumeinfo.Cluster; i += 4)
{
if (mergeByte(currentDir[i], currentDir[i + 1], currentDir[i + 2], currentDir[i + 3]) == 0)
{
currentDir[i] = (byte)ls[0];
currentDir[i + 1] = (byte)(ls[0] >> 8);
currentDir[i + 2] = (byte)(ls[0] >> 16);
currentDir[i + 3] = (byte)(ls[0] >> 24);
//写回磁盘
DiskRW.write(drivename, current.Location, currentDir);
return(ls[0]);
}
continue;
}
//索引表满并且没有下个簇存放
if (mergeByte(currentDir[0], currentDir[1], currentDir[2], currentDir[3]) == 0)
{
//添加下一索引块
byte[] buffer2 = new byte[volumeinfo.Cluster];//写入内容缓存
var l2 = GetFreeBlock(drivename, ref volumeinfo, 1);
//写入上个的索引表
currentDir[0] = (byte)l2[0];
currentDir[1] = (byte)(l2[0] >> 8);
currentDir[2] = (byte)(l2[0] >> 16);
currentDir[3] = (byte)(l2[0] >> 24);
//下个
buffer2[4] = (byte)ls[0];
buffer2[5] = (byte)(ls[0] >> 8);
buffer2[6] = (byte)(ls[0] >> 16);
buffer2[7] = (byte)(ls[0] >> 24);
//写入磁盘
WriteIn(drivename, volumeinfo, l2[0], buffer2);
DiskRW.write(drivename, current.Location, currentDir);
return(ls[0]);
}
currentDir = ReadOut(drivename, volumeinfo, mergeByte(currentDir[0], currentDir[1], currentDir[2], currentDir[3]));
}
}
/// <summary>
/// 向某个空文件添加内容块列表
/// </summary>
/// <param name="drivename">驱动器</param>
/// <param name="fat">实体文件FAT</param>
/// <param name="blocks">内容块</param>
/// <returns></returns>
private static ErrorCode AppendBlock(string drivename, VolumeInfo volumeinfo, FileInfo fat, List <UInt32> blocks)
{
var content = new byte[volumeinfo.Cluster];
UInt16 i1 = (ushort)(volumeinfo.Cluster - 163);//fat簇内可存放多少簇索引
///<summary>
///总共两种情况
///1.fat表即可放入所有索引
///2.fat表和额外的索引表放入
///</summary>
//第一种情况 已测试
if (blocks.Count <= i1)
{
//下一索引表为0
content[160] = 0;
content[161] = 0;
content[162] = 0;
content[163] = 0;
//i是list的索引,j是content的索引
for (int i = 0, j = 164; j < volumeinfo.Cluster; j += 4)
{
content[j] = (byte)blocks[i];
content[j + 1] = (byte)(blocks[i] >> 8);
content[j + 2] = (byte)(blocks[i] >> 16);
content[j + 3] = (byte)(blocks[i] >> 24);
i++;
if (i == blocks.Count)
{
break; //写完
}
}
var res = DiskRW.write(drivename, fat.Location, content);
if (res == false)
{
return(ErrorCode.Fail);
}
return(ErrorCode.Success);
}
//第二种情况
int i2 = 0;//list索引
for (int j = 164; j < volumeinfo.Cluster; i2++, j += 4)
{
content[j] = (byte)blocks[i2];
content[j + 1] = (byte)(blocks[i2] >> 8);
content[j + 2] = (byte)(blocks[i2] >> 16);
content[j + 3] = (byte)(blocks[i2] >> 24);
}
//获取的空闲块列表
var blocklist = GetFreeBlock(drivename, ref volumeinfo, 1);
content[160] = (byte)blocklist[0];
content[161] = (byte)(blocklist[0] >> 8);
content[162] = (byte)(blocklist[0] >> 16);
content[163] = (byte)(blocklist[0] >> 24);
DiskRW.write(drivename, fat.Location, content);
//var blocklist = GetFreeBlock(drivename, ref volumeinfo, 1);
while (true)
{
content = new byte[volumeinfo.Cluster];
for (int j = 4; j < volumeinfo.Cluster; j += 4)
{
content[j] = (byte)blocks[i2];
content[j + 1] = (byte)(blocks[i2] >> 8);
content[j + 2] = (byte)(blocks[i2] >> 16);
content[j + 3] = (byte)(blocks[i2] >> 24);
i2++;
if (i2 == blocks.Count)
{
break;
}
}
if (i2 == blocks.Count)
{
break;
}
var tmp = blocklist[0];//暂存目前块地址
blocklist = GetFreeBlock(drivename, ref volumeinfo, 1);
content[0] = (byte)blocklist[0];
content[1] = (byte)(blocklist[0] >> 8);
content[2] = (byte)(blocklist[0] >> 16);
content[3] = (byte)(blocklist[0] >> 24);
WriteIn(drivename, volumeinfo, tmp, content);
}
WriteIn(drivename, volumeinfo, blocklist[0], content);
return(ErrorCode.Success);
}