/*
 *  ReactOS kernel
 *  Copyright (C) 2002 ReactOS Team
 *
 *  This program is free software; you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License as published by
 *  the Free Software Foundation; either version 2 of the License, or
 *  (at your option) any later version.
 *
 *  This program is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *  GNU General Public License for more details.
 *
 *  You should have received a copy of the GNU General Public License
 *  along with this program; if not, write to the Free Software
 *  Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301, USA.
 *
 * COPYRIGHT:        See COPYING in the top level directory
 * PROJECT:          ReactOS kernel
 * FILE:             drivers/filesystem/ntfs/rw.c
 * PURPOSE:          NTFS filesystem driver
 * PROGRAMMER:       Art Yerkes
 * UPDATE HISTORY:
 */

/* INCLUDES *****************************************************************/

#include <ntddk.h>
#include "ntfs.h"

#define NDEBUG
#include <debug.h>

/* GLOBALS *******************************************************************/

#define ROUND_UP(N, S) ((((N) + (S) - 1) / (S)) * (S))
#define ROUND_DOWN(N, S) ((N) - ((N) % (S)))

/* FUNCTIONS ****************************************************************/

/*
 * FUNCTION: Reads data from a file
 */
static
NTSTATUS
NtfsReadFile(PDEVICE_EXTENSION DeviceExt,
             PFILE_OBJECT FileObject,
             PUCHAR Buffer,
             ULONG Length,
             ULONG ReadOffset,
             ULONG IrpFlags,
             PULONG LengthRead)
{
#if 0
  NTSTATUS Status = STATUS_SUCCESS;
  PUCHAR TempBuffer;
  ULONG TempLength;
  PCCB Ccb;
  PFCB Fcb;

  DPRINT("CdfsReadFile(ReadOffset %lu  Length %lu)\n", ReadOffset, Length);

  *LengthRead = 0;

  if (Length == 0)
    return(STATUS_SUCCESS);

  Ccb = (PCCB)FileObject->FsContext2;
  Fcb = (PFCB)FileObject->FsContext;

  if (ReadOffset >= Fcb->Entry.DataLengthL)
    return(STATUS_END_OF_FILE);

  DPRINT("Reading %d bytes at %d\n", Length, ReadOffset);

  if (!(IrpFlags & (IRP_NOCACHE|IRP_PAGING_IO)))
    {
      LARGE_INTEGER FileOffset;
      IO_STATUS_BLOCK IoStatus;

      if (ReadOffset + Length > Fcb->Entry.DataLengthL)
         Length = Fcb->Entry.DataLengthL - ReadOffset;
      if (FileObject->PrivateCacheMap == NULL)
      {
	  CcRosInitializeFileCache(FileObject, PAGE_SIZE);
      }

      FileOffset.QuadPart = (LONGLONG)ReadOffset;
      CcCopyRead(FileObject,
		 &FileOffset,
		 Length,
		 TRUE,
		 Buffer,
		 &IoStatus);
      *LengthRead = IoStatus.Information;

      return(IoStatus.Status);
    }

  if ((ReadOffset % BLOCKSIZE) != 0 || (Length % BLOCKSIZE) != 0)
    {
      return STATUS_INVALID_PARAMETER;
    }
  if (ReadOffset + Length > ROUND_UP(Fcb->Entry.DataLengthL, BLOCKSIZE))
    Length = ROUND_UP(Fcb->Entry.DataLengthL, BLOCKSIZE) - ReadOffset;

  Status = CdfsReadSectors(DeviceExt->StorageDevice,
			   Fcb->Entry.ExtentLocationL + (ReadOffset / BLOCKSIZE),
			   Length / BLOCKSIZE,
			   Buffer);
  if (NT_SUCCESS(Status))
    {
      *LengthRead = Length;
      if (Length + ReadOffset > Fcb->Entry.DataLengthL)
      {
	memset(Buffer + Fcb->Entry.DataLengthL - ReadOffset,
	       0, Length + ReadOffset - Fcb->Entry.DataLengthL);
      }
    }

  return(Status);
#else
    UNREFERENCED_PARAMETER(DeviceExt);
    UNREFERENCED_PARAMETER(FileObject);
    UNREFERENCED_PARAMETER(Buffer);
    UNREFERENCED_PARAMETER(Length);
    UNREFERENCED_PARAMETER(ReadOffset);
    UNREFERENCED_PARAMETER(IrpFlags);
    *LengthRead = 0;
    return STATUS_END_OF_FILE;
#endif
}


NTSTATUS
NTAPI
NtfsFsdRead(PDEVICE_OBJECT DeviceObject,
            PIRP Irp)
{
    PDEVICE_EXTENSION DeviceExt;
    PIO_STACK_LOCATION Stack;
    PFILE_OBJECT FileObject;
    PVOID Buffer;
    ULONG ReadLength;
    LARGE_INTEGER ReadOffset;
    ULONG ReturnedReadLength = 0;
    NTSTATUS Status = STATUS_SUCCESS;

    DPRINT("NtfsRead(DeviceObject %x, Irp %x)\n",DeviceObject,Irp);

    DeviceExt = DeviceObject->DeviceExtension;
    Stack = IoGetCurrentIrpStackLocation(Irp);
    FileObject = Stack->FileObject;

    ReadLength = Stack->Parameters.Read.Length;
    ReadOffset = Stack->Parameters.Read.ByteOffset;
    Buffer = MmGetSystemAddressForMdl(Irp->MdlAddress);

    Status = NtfsReadFile(DeviceExt,
                          FileObject,
                          Buffer,
                          ReadLength,
                          ReadOffset.u.LowPart,
                          Irp->Flags,
                          &ReturnedReadLength);
    if (NT_SUCCESS(Status))
    {
        if (FileObject->Flags & FO_SYNCHRONOUS_IO)
        {
            FileObject->CurrentByteOffset.QuadPart =
                ReadOffset.QuadPart + ReturnedReadLength;
        }

        Irp->IoStatus.Information = ReturnedReadLength;
    }
    else
    {
        Irp->IoStatus.Information = 0;
    }

    Irp->IoStatus.Status = Status;
    IoCompleteRequest(Irp,IO_NO_INCREMENT);

    return Status;
}


NTSTATUS
NTAPI
NtfsFsdWrite(PDEVICE_OBJECT DeviceObject,
             PIRP Irp)
{
    DPRINT("NtfwWrite(DeviceObject %x Irp %x)\n",DeviceObject,Irp);

    Irp->IoStatus.Status = STATUS_NOT_SUPPORTED;
    Irp->IoStatus.Information = 0;
    return STATUS_NOT_SUPPORTED;
}

/* EOF */