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/*++
Copyright (c) 1989 Microsoft Corporation
Module Name:
FilObSup.c
Abstract:
This module implements the Cdfs File object support routines.
Author:
Brian Andrew [BrianAn] 01-July-1995
Revision History:
--*/
#include "CdProcs.h"
//
// The Bug check file id for this module
//
#define BugCheckFileId (CDFS_BUG_CHECK_FILOBSUP)
//
// Local constants.
//
#define TYPE_OF_OPEN_MASK (0x00000007)
#ifdef ALLOC_PRAGMA
#pragma alloc_text(PAGE, CdDecodeFileObject)
#pragma alloc_text(PAGE, CdFastDecodeFileObject)
#pragma alloc_text(PAGE, CdSetFileObject)
#endif
VOID
CdSetFileObject (
IN PIRP_CONTEXT IrpContext,
IN PFILE_OBJECT FileObject,
IN TYPE_OF_OPEN TypeOfOpen,
IN PFCB Fcb OPTIONAL,
IN PCCB Ccb OPTIONAL
)
/*++
Routine Description:
This routine will initialize the FileObject context fields based on the
input type and data structures.
Arguments:
FileObject - Supplies the file object pointer being initialized.
TypeOfOpen - Sets the type of open.
Fcb - Fcb for this file object. Ignored for UnopenedFileObject.
Ccb - Ccb for the handle corresponding to this file object. Will not
be present for stream file objects.
Return Value:
None.
--*/
{
PAGED_CODE();
//
// We only have values 0 to 7 available so make sure we didn't
// inadvertantly add a new type.
//
ASSERTMSG( "FileObject types exceed available bits\n", BeyondValidType <= 8 );
//
// Setting a file object to type UnopenedFileObject means just
// clearing all of the context fields. All the other input
//
if (TypeOfOpen == UnopenedFileObject) {
FileObject->FsContext =
FileObject->FsContext2 = NULL;
return;
}
//
// Check that the 3 low-order bits of the Ccb are clear.
//
ASSERTMSG( "Ccb is not quad-aligned\n", !FlagOn( ((ULONG) Ccb), TYPE_OF_OPEN_MASK ));
//
// We will or the type of open into the low order bits of FsContext2
// along with the Ccb value.
// The Fcb is stored into the FsContext field.
//
FileObject->FsContext = Fcb;
FileObject->FsContext2 = Ccb;
SetFlag( ((ULONG) FileObject->FsContext2), TypeOfOpen );
//
// Set the Vpb field in the file object.
//
FileObject->Vpb = Fcb->Vcb->Vpb;
return;
}
TYPE_OF_OPEN
CdDecodeFileObject (
IN PIRP_CONTEXT IrpContext,
IN PFILE_OBJECT FileObject,
OUT PFCB *Fcb,
OUT PCCB *Ccb
)
/*++
Routine Description:
This routine takes a file object and extracts the Fcb and Ccb (possibly NULL)
and returns the type of open.
Arguments:
FileObject - Supplies the file object pointer being initialized.
Fcb - Address to store the Fcb contained in the file object.
Ccb - Address to store the Ccb contained in the file object.
Return Value:
TYPE_OF_OPEN - Indicates the type of file object.
--*/
{
TYPE_OF_OPEN TypeOfOpen;
PAGED_CODE();
//
// If this is an unopened file object then return NULL for the
// Fcb/Ccb. Don't trust any other values in the file object.
//
TypeOfOpen = FlagOn( (ULONG) FileObject->FsContext2,
TYPE_OF_OPEN_MASK );
if (TypeOfOpen == UnopenedFileObject) {
*Fcb = NULL;
*Ccb = NULL;
} else {
//
// The Fcb is pointed to by the FsContext field. The Ccb is in
// FsContext2 (after clearing the low three bits). The low three
// bits are the file object type.
//
*Fcb = FileObject->FsContext;
*Ccb = FileObject->FsContext2;
ClearFlag( (ULONG) *Ccb, TYPE_OF_OPEN_MASK );
}
//
// Now return the type of open.
//
return TypeOfOpen;
}
TYPE_OF_OPEN
CdFastDecodeFileObject (
IN PFILE_OBJECT FileObject,
OUT PFCB *Fcb
)
/*++
Routine Description:
This procedure takes a pointer to a file object, that has already been
opened by Cdfs and does a quick decode operation. It will only return
a non null value if the file object is a user file open
Arguments:
FileObject - Supplies the file object pointer being interrogated
Fcb - Address to store Fcb if this is a user file object. NULL
otherwise.
Return Value:
TYPE_OF_OPEN - type of open of this file object.
--*/
{
TYPE_OF_OPEN TypeOfOpen;
PAGED_CODE();
ASSERT_FILE_OBJECT( FileObject );
//
// The Fcb is in the FsContext field. The type of open is in the low
// bits of the Ccb.
//
*Fcb = FileObject->FsContext;
return FlagOn( (ULONG) FileObject->FsContext2, TYPE_OF_OPEN_MASK );
}
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