/// <summary>
/// Create safe file stream
/// </summary>
/// <param name="drive">Driver name</param>
/// <param name="type">Fila access type</param>
/// <returns></returns>
public static unsafe SafeStreamManager CreateStream(string drive, FileAccess type)
{
SafeStreamManager retVal = new SafeStreamManager();
Microsoft.Win32.SafeHandles.SafeFileHandle h;
int n_attempts = 1;
while (n_attempts < MAX_ATTEMPTS_NUMBER)
{
h = CreateFile(drive, type, FileShare.None, 0, FileMode.Open, 0, 0);
if (!h.IsInvalid)
{
Stream inPutFile = new FileStream(h, type);
retVal.SH = h;
retVal.STR = inPutFile;
retVal.f_error = false;
return(retVal);
}
else
{
n_attempts++;
}
}
// Number of attempts over the MAX, CreateFileError
retVal.f_error = true;
return(retVal);
}
/// <summary>
/// Read bytes from DISK
/// </summary>
/// <param name="startingbyte">Byte offset from begin</param>
/// <param name="numberOfBytes"></param>
/// <param name="safeStreamManager"></param>
/// <returns>Read data array</returns>
/// <remarks>
/// You can read a maximum of 2GB block (2.147.483.648 bytes)
/// </remarks>
public static unsafe byte[] ReadBytes(long startingbyte, int numberOfBytes, SafeStreamManager safeStreamManager)
{
byte[] data = new byte[numberOfBytes];
if (!safeStreamManager.SH.IsInvalid)
{
if (safeStreamManager.STR.CanRead)
{
safeStreamManager.STR.Seek(startingbyte, SeekOrigin.Begin);
safeStreamManager.STR.Read(data, 0, numberOfBytes);
return(data);
}
}
return(null);
}
/// <summary>
/// Drop the stream
/// </summary>
/// <param name="safeStreamManager"></param>
/// <returns>true=OK false=error</returns>
public static unsafe bool DropStream(SafeStreamManager safeStreamManager)
{
try
{
safeStreamManager.STR.Close();
safeStreamManager.SH.Close();
return(true);
}
catch (Exception)
{
return(false);
throw;
}
}
/// <summary>
/// Write blocks to DISK
/// </summary>
/// <param name="startingBlock"></param>
/// <param name="numberOfBlocks"></param>
/// <param name="blockSize"></param>
/// <param name="data"></param>
/// <param name="safeStreamManager"></param>
/// <returns>0 ok -1 error</returns>
/// <remarks>
/// You can write a maximum of 2GB block (4.194.304 blocks)
/// </remarks>
public static unsafe int WriteBlocks(long startingBlock, int numberOfBlocks, int blockSize, byte[] data, SafeStreamManager safeStreamManager)
{
if (!safeStreamManager.SH.IsInvalid)
{
if (safeStreamManager.STR.CanRead)
{
safeStreamManager.STR.Seek(startingBlock * blockSize, SeekOrigin.Begin);
safeStreamManager.STR.Write(data, 0, numberOfBlocks * blockSize);
safeStreamManager.STR.Flush();
return(0);
}
}
return(-1);
}
/// <summary>
/// Read block from DISK
/// </summary>
/// <param name="startingBlock"></param>
/// <param name="numberOfBlocks"></param>
/// <param name="blockSize"></param>
/// <param name="safeStreamManager"></param>
/// <returns>Read data array</returns>
/// <remarks>
/// You can read a maximum of 2GB block (4.194.304 blocks)
/// </remarks>
public static unsafe byte[] ReadBlocks(long startingBlock, int numberOfBlocks, int blockSize, SafeStreamManager safeStreamManager)
{
byte[] data = new byte[numberOfBlocks * blockSize];
if (!safeStreamManager.SH.IsInvalid)
{
if (safeStreamManager.STR.CanRead)
{
safeStreamManager.STR.Seek(startingBlock * blockSize, SeekOrigin.Begin);
safeStreamManager.STR.Read(data, 0, numberOfBlocks * blockSize);
return(data);
}
}
return(null);
}
